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diff --git a/doc/BLT.n b/doc/BLT.n
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+'\"
+'\" Copyright 1991-1997 by Bell Labs Innovations for Lucent Technologies.
+'\"
+'\" Permission to use, copy, modify, and distribute this software and its
+'\" documentation for any purpose and without fee is hereby granted, provided
+'\" that the above copyright notice appear in all copies and that both that the
+'\" copyright notice and warranty disclaimer appear in supporting documentation,
+'\" and that the names of Lucent Technologies any of their entities not be used
+'\" in advertising or publicity pertaining to distribution of the software
+'\" without specific, written prior permission.
+'\"
+'\" Lucent Technologies disclaims all warranties with regard to this software,
+'\" including all implied warranties of merchantability and fitness.  In no event
+'\" shall Lucent Technologies be liable for any special, indirect or
+'\" consequential damages or any damages whatsoever resulting from loss of use,
+'\" data or profits, whether in an action of contract, negligence or other
+'\" tortuous action, arising out of or in connection with the use or performance
+'\" of this software.  
+'\"
+.so man.macros
+.TH intro n BLT_VERSION BLT "BLT Built-In Commands"
+.BS
+'\" Note:  do not modify the .SH NAME line immediately below!
+.SH NAME
+BLT \- Introduction to the BLT library
+.BE
+.SH DESCRIPTION
+BLT is a library of extensions to the Tk library.  It adds new
+commands and variables to the application's interpreter.
+.LP
+.SH COMMANDS
+The following commands are added to the interpreter from the BLT library:
+.TP 15
+\fBtable\fR 
+A table geometry manager for Tk.  You specify window placements as table 
+row,column positions and windows can also span multiple rows or columns. 
+It also has many options for setting and/or bounding window sizes.
+.TP 15
+\fBgraph\fR 
+A 2D plotting widget.  Plots two variable data in a window with an optional 
+legend and annotations.   It has of several components; coordinate axes, 
+crosshairs, a legend, and a collection of elements and tags.
+.TP 15
+\fBbarchart\fR 
+A barchart widget.  Plots two-variable data as rectangular bars in a 
+window.  The x-coordinate values designate the position of the bar along 
+the x-axis, while the y-coordinate values designate the magnitude.
+The \fBbarchart\fR widget has of several components; coordinate axes, 
+crosshairs, a legend, and a collection of elements and tags.
+.TP 15
+\fBvector\fR 
+Creates a vector of floating point values.  The vector's components
+can be manipulated in three ways: through a Tcl array variable, a Tcl
+command, or the C API.
+.TP
+\fBspline\fR
+Computes a spline fitting a set of data points (x and y vectors) and
+produces a vector of the interpolated images (y-coordinates) at a
+given set of x-coordinates.
+.TP 15
+\fBbgexec\fR 
+Like Tcl's \fBexec\fR command, \fBbgexec\fR runs a pipeline of Unix 
+commands in the background.  Unlike \fBexec\fR, the output of the last
+process is collected and a global Tcl variable is set upon its completion.
+\fBbgexec\fR can be used with \fBtkwait\fR to wait for Unix commands
+to finish while still handling expose events.  Intermediate output is
+also available while the pipeline is active.
+.TP 15
+\fBbusy\fR 
+Creates a "busy window" which prevents user-interaction when an
+application is busy.  The busy window also provides an easy way 
+to have temporary busy cursors (such as a watch or hourglass).
+.TP 15
+\fBbitmap\fR 
+Reads and writes bitmaps from Tcl.  New X bitmaps can be defined
+on-the-fly from Tcl, obviating the need to copy around bitmap files.  
+Other options query loaded X bitmap's dimensions and data.
+.TP 15
+\fBdrag&drop\fR 
+Provides a drag-and-drop facility for Tk.  Information (represented
+by a token window) can be dragged to and from any Tk window, including
+those of another Tk application.  \fBdrag&drop\fR acts as a 
+coordinator, directing Tk \fBsend\fR commands between (or within) TCL/Tk 
+applications. 
+.TP 15
+\fBhtext\fR 
+A simple hypertext widget.  Combines text and Tk widgets into a single
+scroll-able window.  Tcl commands can be embedded into text, which are
+invoked as the text is parsed.  In addition, Tk widgets can be
+appended to the window at the current point in the text.  \fBHtext\fR
+can be also used to create scrolled windows of Tk widgets.
+.TP 15
+\fBwinop\fR 
+Raise, lower, map, or, unmap any window.  The raise and lower functions
+are useful for stacking windows above or below "busy windows".
+.TP 15
+\fBwatch\fR 
+Arranges for Tcl procedures to be called before and/or after the execution
+of every Tcl command. This command
+may be used in the logging, profiling, or tracing of Tcl code.
+.TP 15
+\fBbltdebug\fR 
+A simple Tcl command tracing facility useful for debugging Tcl code.  
+Displays each Tcl command before and after substitution along its level 
+in the interpreter on standard error.
+.SH VARIABLES
+.PP
+The following Tcl variables are either set or used by BLT at various times
+in its execution:
+.TP 15
+\fBblt_library\fR
+This variable contains the name of a directory containing a library
+of Tcl scripts and other files related to BLT.  Currently, this 
+directory contains the \fBdrag&drop\fR protocol scripts and the 
+PostScript prolog
+used by \fBgraph\fR and \fBbarchart\fR.
+The value of this variable is taken from the BLT_LIBRARY environment
+variable, if one exists, or else from a default value compiled into
+the \fBBLT\fR library.
+.TP 15
+\fBblt_versions\fR 
+This variable is set in the interpreter for each application. It is an 
+array of the current version numbers for each 
+of the BLT commands in the form \fImajor\fR.\fIminor\fR.  \fIMajor\fR and
+\fIminor\fR are integers.  The major version number increases in
+any command that includes changes that are not backward compatible
+(i.e. whenever existing applications and scripts may have to change to
+work with the new release).  The minor version number increases with
+each new release of a command, except that it resets to zero whenever the
+major version number changes.  The array is indexed by the individual 
+command name.
+.SH ADDING BLT TO YOUR APPLICATIONS
+It's easy to add BLT to an existing Tk application.  BLT requires no 
+patches or edits to the Tcl or Tk libraries.  To add BLT, simply add the 
+following code snippet to your application's tkAppInit.c file.  
+.CS
+if (Blt_Init(interp) != TCL_OK) {
+    return TCL_ERROR;
+}
+.CE
+Recompile and link with the BLT library (libBLT.a) and that's it.
+.PP
+Alternately, you can dynamically load BLT, simply by invoking the
+command
+.CS
+package require BLT
+.CE
+from your Tcl script.
+.SH BUGS
+Send bug reports, requests, suggestions, etc. to 
+gah@siliconmetrics.com or ghowlett@grandecom.net
+.SH KEYWORDS
+BLT
diff --git a/doc/barchart.n b/doc/barchart.n
new file mode 100644
index 0000000..ec2b5f4
--- /dev/null
+++ b/doc/barchart.n
@@ -0,0 +1,2236 @@
+'\"
+'\" Copyright 1991-1998 by Bell Labs Innovations for Lucent Technologies.
+'\"
+'\" Permission to use, copy, modify, and distribute this software and its
+'\" documentation for any purpose and without fee is hereby granted, provided
+'\" that the above copyright notice appear in all copies and that both that the
+'\" copyright notice and warranty disclaimer appear in supporting documentation,
+'\" and that the names of Lucent Technologies any of their entities not be used
+'\" in advertising or publicity pertaining to distribution of the software
+'\" without specific, written prior permission.
+'\"
+'\" Lucent Technologies disclaims all warranties with regard to this software,
+'\" including all implied warranties of merchantability and fitness.  In no event
+'\" shall Lucent Technologies be liable for any special, indirect or
+'\" consequential damages or any damages whatsoever resulting from loss of use,
+'\" data or profits, whether in an action of contract, negligence or other
+'\" tortuous action, arising out of or in connection with the use or performance
+'\" of this software.  
+'\"
+'\" Barchart widget created by Sani Nassif and George Howlett.
+'\"
+.so man.macros
+.TH barchart n BLT_VERSION BLT "BLT Built-In Commands"
+.BS
+'\" Note:  do not modify the .SH NAME line immediately below!
+.SH NAME
+barchart \-  Bar chart for plotting X-Y coordinate data.
+.SH SYNOPSIS
+\fBbarchart\fI \fIpathName \fR?\fIoption value\fR?...
+.BE
+.SH DESCRIPTION
+The \fBbarchart\fR command creates a bar chart for plotting
+two-dimensional data (X-Y coordinates). A bar chart is a graphic means
+of comparing numbers by displaying bars of lengths proportional to the
+y-coordinates of the points they represented.  The bar chart has many
+configurable components: coordinate axes, elements, legend, grid
+lines, cross hairs, etc.  They allow you to customize the look and
+feel of the graph.
+.SH INTRODUCTION
+The \fBbarchart\fR command creates a new window for plotting
+two-dimensional data (X-Y coordinates), using bars of
+various lengths to represent the data points.  The bars are drawn in a
+rectangular area displayed in the center of the new window.  This is the
+\fIplotting area\fR.  The coordinate axes are drawn in
+the margins surrounding the plotting area.  By default, the legend is
+drawn in the right margin.  The title is displayed in top margin.
+.PP
+A \fBbarchart\fR widget has several configurable components:
+coordinate axes, data elements, legend, grid, cross hairs, pens,
+postscript, and annotation markers.  Each component can be queried or
+modified.
+.TP 1i
+\f(CWaxis\fR 
+
+Up to four coordinate axes (two X\-coordinate and two Y\-coordinate
+axes) can be displayed, but you can create and use any number of
+axes. Axes control what region of data is displayed and how the data
+is scaled. Each axis consists of the axis line, title, major and minor
+ticks, and tick labels. Tick labels display the value at each major
+tick.
+.TP 1i
+\f(CWcrosshairs\fR 
+Cross hairs are used to position the mouse pointer relative to the X
+and Y coordinate axes. Two perpendicular lines, intersecting at the
+current location of the mouse, extend across the plotting area to the
+coordinate axes.
+.TP 1i
+\f(CWelement\fR 
+An element represents a set of data to be plotted.  It contains an x
+and y vector of values representing the data points.  Each
+data point is displayed as a bar where the length of the bar is
+proportional to the ordinate (Y-coordinate) of the data point.
+The appearance of the bar, such as its color, stipple, or relief
+is configurable.
+.sp
+A special case exists when two or more data points have the same
+abscissa (X-coordinate).  By default, the bars are overlayed, one on
+top of the other.  The bars are drawn in the order of the element
+display list.  But you can also configure the bars to be displayed in
+two other ways.  They may be displayed as a stack, where each bar
+(with the same abscissa) is stacked on the previous.  Or they can be
+drawn side-by-side as thin bars.  The width of each bar is a function
+of the number of data points with the same abscissa.
+.TP 1i
+\f(CWgrid\fR
+Extends the major and minor ticks of the X\-axis and/or Y\-axis across the 
+plotting area. 
+.TP 1i
+\f(CWlegend\fR 
+The legend displays the name and symbol of each data element. 
+The legend can be drawn in any margin or in the plotting area.
+.TP 1i
+\f(CWmarker\fR
+Markers are used annotate or highlight areas of the graph. For
+example, you could use a text marker to label a particular data
+point. Markers come in various forms: text strings, bitmaps, connected
+line segments, images, polygons, or embedded widgets.
+.TP 1i
+\f(CWpen\fR 
+Pens define attributes for elements.  Data elements use pens to
+specify how they should be drawn.  A data element may use many pens at
+once.  Here the particular pen used for a data point is determined
+from each element's weight vector (see the element's \fB\-weight\fR
+and \fB\-style\fR options).
+.TP 1i
+\f(CWpostscript\fR
+The widget can generate encapsulated PostScript output. This component
+has several options to configure how the PostScript is generated.
+.SH SYNTAX
+.DS
+\fBbarchart \fIpathName \fR?\fIoption value\fR?...
+.DE
+The \fBbarchart\fR command creates a new window \fIpathName\fR and makes
+it into a \fBbarchart\fR widget.  At the time this command is invoked, there
+must not exist a window named \fIpathName\fR, but \fIpathName\fR's
+parent must exist.  Additional options may be specified on the
+command line or in the option database to configure aspects of the
+graph such as its colors and font.  See the \fBconfigure\fR operation
+below for the exact details about what \fIoption\fR and \fIvalue\fR
+pairs are valid.
+.PP
+If successful, \fBbarchart\fR returns the path name of the widget.  It
+also creates a new Tcl command by the same name.  You can use this
+command to invoke various operations that query or modify the graph.
+The general form is:
+.DS
+\fIpathName \fIoperation\fR \fR?\fIarg\fR?...
+.DE
+Both \fIoperation\fR and its arguments determine the exact behavior of
+the command.  The operations available for the graph are described in 
+the 
+.SB "BARCHART OPERATIONS"
+section.
+.PP
+The command can also be used to access components of the graph.
+.DS
+\fIpathName component operation\fR ?\fIarg\fR?...
+.DE
+The operation, now located after the name of the component, is the
+function to be performed on that component. Each component has its own
+set of operations that manipulate that component.  They will be
+described below in their own sections.
+.SH EXAMPLE
+The \fBbarchart\fR command creates a new bar chart.  
+.CS
+# Create a new bar chart.  Plotting area is black.
+barchart .b -plotbackground black
+.CE
+A new Tcl command \f(CW.b\fR is created.  This command can be used
+to query and modify the bar chart.  For
+example, to change the title of the graph to "My Plot", you use the
+new command and the \fBconfigure\fR operation.
+.CS
+# Change the title.
+\&.b configure -title "My Plot"
+.CE
+To add data elements, you use the command and the \fBelement\fR component.
+.CS
+# Create a new element named "e1"
+\&.b element create e1 \\
+	-xdata { 1 2 3 4 5 6 7 8 9 10 } \\
+	-ydata { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 
+		155.85 166.60 175.38 }
+.CE
+The element's X-Y coordinates are specified using lists of
+numbers.  Alternately, BLT vectors could be used to hold the X-Y
+coordinates.
+.CS
+# Create two vectors and add them to the barchart.
+vector xVector yVector
+xVector set { 1 2 3 4 5 6 7 8 9 10 }
+yVector set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85 
+	166.60 175.38 }
+\&n.b element create e1 -xdata xVector -ydata yVector
+.CE
+The advantage of using vectors is that when you modify one, the graph
+is automatically redrawn to reflect the new values.
+.CS
+# Change the y coordinate of the first point.
+set yVector(0) 25.18
+.CE
+An element named \f(CWe1\fR is now created in \f(CW.b\fR.  It 
+is automatically added to the display list of elements.  You can
+use this list to control in what order elements are displayed.
+To query or reset the element display list, you use the element's 
+\fBshow\fR operation.
+.CS
+# Get the current display list 
+set elemList [.b element show]
+# Remove the first element so it won't be displayed.
+\&.b element show [lrange $elemList 0 end]
+.CE
+The element will be displayed by as many bars as there are data points
+(in this case there are ten).  The bars will be drawn centered at the
+x-coordinate of the data point.  All the bars will have the same
+attributes (colors, stipple, etc).  The width of each bar is by
+default one unit.  You can change this with using the \fB\-barwidth\fR
+option.
+.CS
+# Change the scale of the x-coordinate data 
+xVector set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }
+# Make sure we change the bar width too.
+\&.b configure -barwidth 0.2
+.CE
+The height of each bar is proportional to the ordinate (Y-coordinate)
+of the data point.
+.PP
+If two or more data points have the same abscissa (X-coordinate
+value), the bars representing those data points may be drawn in 
+various ways.
+The default is to overlay the bars, one on top of the other.
+The ordering is determined from the of element display list.  If
+the stacked mode is selected (using the \fB\-barmode\fR configuration
+option), the bars are stacked, each bar above the previous.
+.CS
+# Display the elements as stacked.
+\&.b configure -barmode stacked
+.CE
+If the aligned mode is selected, the bars having the same
+x-coordinates are displayed side by side.  The width of each bar is a
+fraction of its normal width, based upon the number of bars with the
+same x-coordinate.
+.CS
+# Display the elements side-by-side.
+\&.b configure -barmode aligned
+.CE
+By default, the element's label in the legend will be also
+\f(CWe1\fR.  You can change the label, or specify no legend entry,
+again using the element's \fBconfigure\fR operation.
+.CS
+# Don't display "e1" in the legend.
+\&.b element configure e1 -label ""
+.CE
+You can configure more than just the element's label.  An element has
+many attributes such as stipple, foreground and background colors,
+relief, etc.
+.CS
+\&.b element configure e1 -fg red -bg pink \\
+	-stipple gray50
+.CE
+Four coordinate axes are automatically created: \f(CWx\fR, \f(CWx2\fR,
+\f(CWy\fR, and \f(CWy2\fR.  And by default, elements are mapped onto the
+axes \f(CWx\fR and \f(CWy\fR.  This can be changed with the \fB\-mapx\fR
+and \fB\-mapy\fR options.
+.CS
+# Map "e1" on the alternate y axis "y2".
+\&.b element configure e1 -mapy y2
+.CE
+Axes can be configured in many ways too.  For example, you change the
+scale of the Y\-axis from linear to log using the \fBaxis\fR component.
+.CS
+# Y-axis is log scale.
+\&.b axis configure y -logscale yes
+.CE
+One important way axes are used is to zoom in on a particular data
+region.  Zooming is done by simply specifying new axis limits using
+the \fB\-min\fR and \fB\-max\fR configuration options.
+.CS
+\&.b axis configure x \-min 1.0 \-max 1.5
+\&.b axis configure y \-min 12.0 \-max 55.15
+.CE
+To zoom interactively, you link the\fBaxis configure\fR operations with
+some user interaction (such as pressing the mouse button), using the
+\fBbind\fR command.  To convert between screen and graph coordinates,
+use the \fBinvtransform\fR operation.
+.CS
+# Click the button to set a new minimum 
+bind .b <ButtonPress-1> { 
+    %W axis configure x \-min [%W axis invtransform x %x]
+    %W axis configure x \-min [%W axis invtransform x %y]
+}
+.CE
+By default, the limits of the axis are determined from data values.
+To reset back to the default limits, set the \fB\-min\fR and
+\fB\-max\fR options to the empty value.
+.CS
+# Reset the axes to autoscale again.
+\&.b axis configure x \-min {} \-max {}
+\&.b axis configure y \-min {} \-max {}
+.CE
+By default, the legend is drawn in the right margin.  You can
+change this or any legend configuration options using the
+\fBlegend\fR component.
+.CS
+# Configure the legend font, color, and relief
+\&.b legend configure -position left -relief raised \\
+	-font fixed -fg blue
+.CE
+To prevent the legend from being displayed, turn on the \fB\-hide\fR
+option.
+.CS
+# Don't display the legend.
+\&.b legend configure \-hide yes\fR
+.CE
+The \fBbarchart\fR has simple drawing procedures called markers.  They can be
+used to highlight or annotate data in the graph. The types of markers
+available are bitmaps, polygons, lines, or windows.  Markers can be
+used, for example, to mark or brush points.  For example there may be
+a line marker which indicates some low-water value.  Markers are created
+using the \fBmarker\fR operation.
+.CS
+# Create a line represent the low water mark at 10.0
+\&.b marker create line -name "low_water" \\
+	-coords { -Inf 10.0 Inf 10.0 } \\
+	-dashes { 2 4 2 } -fg red -bg blue 
+.CE
+This creates a line marker named \f(CWlow_water\fR.  It will display a
+horizontal line stretching across the plotting area at the
+y-coordinate 10.0.  The coordinates "-Inf" and "Inf" indicate the
+relative minimum and maximum of the axis (in this case the x-axis).  By
+default, markers are drawn last, on top of the bars.  You can change this
+with the \fB\-under\fR option.
+.CS
+# Draw the marker before elements are drawn.
+\&.b marker configure low_water -under yes
+.CE
+You can add cross hairs or grid lines using the \fBcrosshairs\fR and
+\fBgrid\fR components.
+.CS
+# Display both cross hairs and grid lines.
+\&.b crosshairs configure -hide no -color red
+\&.b grid configure -hide no -dashes { 2 2 }
+.CE
+Finally, to get hardcopy of the graph, use the \fBpostscript\fR
+component.
+.CS
+# Print the bar chart into file "file.ps"
+\&.b postscript output file.ps -maxpect yes -decorations no
+.CE
+This generates a file \f(CWfile.ps\fR containing the encapsulated
+PostScript of the graph.  The option \fB\-maxpect\fR says to scale the
+plot to the size of the page.  Turning off the \fB\-decorations\fR
+option denotes that no borders or color backgrounds should be
+drawn (i.e. the background of the margins, legend, and plotting
+area will be white).
+.SH SYNTAX
+.DS
+\fBbarchart \fIpathName \fR?\fIoption value\fR?...
+.DE
+The \fBbarchart\fR command creates a new window \fIpathName\fR and makes
+it into a barchart widget.  At the time this command is invoked, there
+must not exist a window named \fIpathName\fR, but \fIpathName\fR's
+parent must exist.  Additional options may may be specified on the
+command line or in the option database to configure aspects of the
+bar chart such as its colors and font.  See the \fBconfigure\fR operation
+below for the exact details as to what \fIoption\fR and \fIvalue\fR
+pairs are valid.
+.PP
+If successful, \fBbarchart\fR returns \fIpathName\fR. It also creates a
+new Tcl command \fIpathName\fR.  This command may be used to invoke
+various operations to query or modify the bar chart.  It has the general
+form:
+.DS
+\fIpathName \fIoperation\fR \fR?\fIarg\fR?...
+.DE
+Both \fIoperation\fR and its arguments determine the exact behavior of
+the command.  The operations available for the bar chart are described in
+the following section.
+.SH "BARCHART OPERATIONS"
+.TP
+\fIpathName \fBbar \fIelemName \fR?\fIoption value\fR?...
+Creates a new barchart element \fIelemName\fR.  It's an
+error if an element \fIelemName\fR already exists.  
+See the manual for \fBbarchart\fR for details about
+what \fIoption\fR and \fIvalue\fR pairs are valid.
+.TP
+\fIpathName \fBcget\fR \fIoption\fR
+Returns the current value of the configuration option given by
+\fIoption\fR.  \fIOption\fR may be any option described
+below for the \fBconfigure\fR operation.
+.TP
+\fIpathName \fBconfigure \fR?\fIoption value\fR?...
+Queries or modifies the configuration options of the graph.  If
+\fIoption\fR isn't specified, a list describing the current
+options for \fIpathName\fR is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is returned.
+If one or more \fIoption\fR and \fIvalue\fR pairs are specified, then
+for each pair, the option \fIoption\fR is set to \fIvalue\fR.
+The following options are valid.
+.RS
+.TP
+\fB\-background \fIcolor\fR
+Sets the background color. This includes the margins and
+legend, but not the plotting area.
+.TP
+\fB\-barmode \fImode\fR 
+Indicates how related bar elements will be drawn.  Related elements
+have data points with the same abscissas (X-coordinates). \fIMode\fR
+indicates how those segments should be drawn. \fIMode\fR can be
+\f(CWinfront\fR, \f(CWaligned\fR, \f(CWoverlap\fR, or \f(CWstacked\fR.
+The default mode is \f(CWinfront\fR.
+.RS
+.TP 1i
+\f(CWinfront\fR
+Each successive segment is drawn in front of the previous. 
+.TP 1i
+\f(CWstacked\fR
+Each successive segment is stacked vertically on top of the previous.  
+.TP 1i
+\f(CWaligned\fR
+Segments is displayed aligned from right-to-left.  
+.TP 1i
+\f(CWoverlap\fR
+Like \f(CWaligned\fR but segments slightly overlap each other.  
+.RE
+.TP
+\fB\-barwidth \fIvalue\fR 
+Specifies the width of the bars.  This value can be overrided by the
+individual elements using their \fB\-barwidth\fR configuration option.
+\fIValue\fR is the width in terms of graph-coordinates.  The
+default width is \f(CW1.0\fR.
+.TP
+\fB\-borderwidth \fIpixels\fR
+Sets the width of the 3\-D border around the outside edge of the widget.  The
+\fB\-relief\fR option determines if the border is to be drawn.  The
+default is \f(CW2\fR.
+.TP
+\fB\-bottommargin \fIpixels\fR
+Specifies the size of the margin below the X\-coordinate axis.  If
+\fIpixels\fR is \f(CW0\fR, the size of the margin is selected automatically.
+The default is \f(CW0\fR.
+.TP
+\fB\-bufferelements \fIboolean\fR
+Indicates whether an internal pixmap to buffer the display of data
+elements should be used.  If \fIboolean\fR is true, data elements are
+drawn to an internal pixmap.  This option is especially useful when
+the graph is redrawn frequently while the remains data unchanged (for
+example, moving a marker across the plot).  See the
+.SB "SPEED TIPS"
+section.
+The default is \f(CW1\fR.
+.TP
+\fB\-cursor \fIcursor\fR
+Specifies the widget's cursor.  The default cursor is \f(CWcrosshair\fR.
+.TP
+\fB\-font \fIfontName\fR 
+Specifies the font of the graph title. The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-18-180-*\fR.
+.TP
+\fB\-halo \fIpixels\fR 
+Specifies a maximum distance to consider when searching for the
+closest data point (see the element's \fBclosest\fR operation below).
+Data points further than \fIpixels\fR away are ignored.  The default is
+\f(CW0.5i\fR.
+.TP
+\fB\-height \fIpixels\fR
+Specifies the requested height of widget.  The default is
+\f(CW4i\fR.
+.TP
+\fB\-invertxy \fIboolean\fR
+Indicates whether the placement X\-axis and Y\-axis should be inverted.  If
+\fIboolean\fR is true, the X and Y axes are swapped.  The default is
+\f(CW0\fR.
+.TP
+\fB\-justify \fIjustify\fR
+Specifies how the title should be justified.  This matters only when
+the title contains more than one line of text. \fIJustify\fR must be
+\f(CWleft\fR, \f(CWright\fR, or \f(CWcenter\fR.  The default is
+\f(CWcenter\fR.
+.TP
+\fB\-leftmargin \fIpixels\fR
+Sets the size of the margin from the left edge of the window to 
+the Y\-coordinate axis.  If \fIpixels\fR is \f(CW0\fR, the size is
+calculated automatically.  The default is \f(CW0\fR.
+.TP
+\fB\-plotbackground \fIcolor\fR
+Specifies the background color of the plotting area.  The default is
+\f(CWwhite\fR.
+.TP
+\fB\-plotborderwidth \fIpixels\fR
+Sets the width of the 3-D border around the plotting area.  The
+\fB\-plotrelief\fR option determines if a border is drawn.  The
+default is \f(CW2\fR.
+.TP
+\fB\-plotpadx \fIpad\fR
+Sets the amount of padding to be added to the left and right sides of
+the plotting area.  \fIPad\fR can be a list of one or two screen
+distances.  If \fIpad\fR has two elements, the left side of the
+plotting area entry is padded by the first distance and the right side
+by the second.  If \fIpad\fR is just one distance, both the left and
+right sides are padded evenly.  The default is \f(CW8\fR.
+.TP
+\fB\-plotpady \fIpad\fR
+Sets the amount of padding to be added to the top and bottom of the
+plotting area.  \fIPad\fR can be a list of one or two screen
+distances.  If \fIpad\fR has two elements, the top of the plotting
+area is padded by the first distance and the bottom by the second.  If
+\fIpad\fR is just one distance, both the top and bottom are padded
+evenly.  The default is \f(CW8\fR.
+.TP
+\fB\-plotrelief \fIrelief\fR
+Specifies the 3-D effect for the plotting area.  \fIRelief\fR
+specifies how the interior of the plotting area should appear relative
+to rest of the graph; for example, \f(CWraised\fR means the plot should
+appear to protrude from the graph, relative to the surface of the
+graph.  The default is \f(CWsunken\fR.
+.TP
+\fB\-relief \fIrelief\fR
+Specifies the 3-D effect for the barchart widget.  \fIRelief\fR
+specifies how the graph should appear relative to widget it is packed
+into; for example, \f(CWraised\fR means the graph should
+appear to protrude.  The default is \f(CWflat\fR.
+.TP
+\fB\-rightmargin \fIpixels\fR
+Sets the size of margin from the plotting area to the right edge of
+the window.  By default, the legend is drawn in this margin.  If
+\fIpixels\fR is than 1, the margin size is selected automatically.
+.TP
+\fB\-takefocus\fR \fIfocus\fR 
+Provides information used when moving the focus from window to window
+via keyboard traversal (e.g., Tab and Shift-Tab).  If \fIfocus\fR is
+\f(CW0\fR, this means that this window should be skipped entirely during
+keyboard traversal.  \f(CW1\fR means that the this window should always
+receive the input focus.  An empty value means that the traversal
+scripts make the decision whether to focus on the window.
+The default is \f(CW""\fR.
+.TP
+\fB\-tile \fIimage\fR 
+Specifies a tiled background for the widget.  If \fIimage\fR isn't
+\f(CW""\fR, the background is tiled using \fIimage\fR.
+Otherwise, the normal background color is drawn (see the
+\fB\-background\fR option).  \fIImage\fR must be an image created
+using the Tk \fBimage\fR command.  The default is \f(CW""\fR.
+.TP
+\fB\-title \fItext\fR 
+Sets the title to \fItext\fR. If \fItext\fR is \f(CW""\fR,
+no title will be displayed.
+.TP
+\fB\-topmargin \fIpixels\fR
+Specifies the size of the margin above the x2 axis.  If \fIpixels\fR
+is \f(CW0\fR, the margin size is calculated automatically.
+.TP
+\fB\-width \fIpixels\fR
+Specifies the requested width of the widget.  The default is
+\f(CW5i\fR.
+.RE
+.TP
+\fIpathName \fBcrosshairs \fIoperation \fR?\fIarg\fR?
+See the 
+.SB "CROSSHAIRS COMPONENT"
+section.
+.TP
+\fIpathName \fBelement \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "ELEMENT COMPONENTS"
+section.
+.TP
+\fIpathName \fBextents \fIitem\fR 
+Returns the size of a particular item in the graph.  \fIItem\fR must
+be either \f(CWleftmargin\fR, \f(CWrightmargin\fR, \f(CWtopmargin\fR,
+\f(CWbottommargin\fR, \f(CWplotwidth\fR, or \f(CWplotheight\fR.
+.TP
+\fIpathName \fBgrid \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "GRID COMPONENT"
+section.
+.TP
+\fIpathName \fBinvtransform \fIwinX winY\fR 
+Performs an inverse coordinate transformation, mapping window
+coordinates back to graph-coordinates, using the standard X\-axis and Y\-axis.
+Returns a list of containing the X-Y graph-coordinates.
+.TP
+\fIpathName \fBinside \fIx y\fR
+Returns \f(CW1\fR is the designated screen-coordinate (\fIx\fR and \fIy\fR)
+is inside the plotting area and \f(CW0\fR otherwise.
+.TP
+\fIpathName \fBlegend \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "LEGEND COMPONENT"
+section.
+.TP
+\fIpathName \fBline\fB operation arg\fR...
+The operation is the same as \fBelement\fR.
+.TP
+\fIpathName \fBmarker \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "MARKER COMPONENTS"
+section.
+.TP
+\fIpathName\fR \fBmetafile\fR ?\fIfileName\fR?
+\fIThis operation is for Window platforms only\fR.  
+Creates a Windows enhanced metafile of the barchart.
+If present, \fIfileName\fR is the file name of the new metafile.
+Otherwise, the metafile is automatically added to the clipboard.
+.TP
+\fIpathName \fBpostscript \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "POSTSCRIPT COMPONENT"
+section.
+.TP
+\fIpathName \fBsnap \fIphotoName\fR
+Takes a snapshot of the graph and stores the contents in the photo
+image \fIphotoName\fR.  \fIPhotoName\fR is the name of a Tk photo
+image that must already exist.
+.TP
+\fIpathName \fBtransform \fIx y\fR 
+Performs a coordinate transformation, mapping graph-coordinates to
+window coordinates, using the standard X\-axis and Y\-axis.
+Returns a list containing the X\-Y screen-coordinates.
+.TP
+\fIpathName \fBxaxis \fIoperation\fR ?\fIarg\fR?...
+.TP
+\fIpathName \fBx2axis \fIoperation\fR ?\fIarg\fR?... 
+.TP
+\fIpathName \fByaxis \fIoperation\fR ?\fIarg\fR?... 
+.TP
+\fIpathName \fBy2axis \fIoperation\fR ?\fIarg\fR?... 
+See the 
+.SB "AXIS COMPONENTS"
+section.
+.SH "BARCHART COMPONENTS"
+A graph is composed of several components: coordinate axes, data
+elements, legend, grid, cross hairs, postscript, and annotation
+markers. Instead of one big set of configuration options and
+operations, the graph is partitioned, where each component has its own
+configuration options and operations that specifically control that
+aspect or part of the graph. 
+.SS "AXIS COMPONENTS"
+Four coordinate axes are automatically created: two X\-coordinate axes
+(\f(CWx\fR and \f(CWx2\fR) and two Y\-coordinate axes (\f(CWy\fR, and
+\f(CWy2\fR).  By default, the axis \f(CWx\fR is located in the bottom
+margin, \f(CWy\fR in the left margin, \f(CWx2\fR in the top margin, and
+\f(CWy2\fR in the right margin.
+.PP
+An axis consists of the axis line, title, major and minor ticks, and
+tick labels.  Major ticks are drawn at uniform intervals along the
+axis.  Each tick is labeled with its coordinate value.  Minor ticks
+are drawn at uniform intervals within major ticks.  
+.PP
+The range of the axis controls what region of data is plotted.
+Data points outside the minimum and maximum limits of the axis are
+not plotted.  By default, the minimum and maximum limits are
+determined from the data, but you can reset either limit.
+.PP
+You can create and use several axes. To create an axis, invoke
+the axis component and its create operation.
+.CS
+# Create a new axis called "temperature"
+\&.b axis create temperature
+.CE
+You map data elements to an axis using the element's \-mapy and \-mapx
+configuration options. They specify the coordinate axes an element
+is mapped onto.
+.CS
+# Now map the temperature data to this axis.
+\&.b element create "temp" \-xdata $x \-ydata $tempData \\
+    \-mapy temperature
+.CE
+While you can have many axes, only four axes can be displayed
+simultaneously.  They are drawn in each of the margins surrounding
+the plotting area.  The axes \f(CWx\fR and \f(CWy\fR are drawn in the
+bottom and left margins. The axes \f(CWx2\fR and \f(CWy2\fR are drawn in
+top and right margins.  Only \f(CWx\fR and \f(CWy\fR are shown by
+default. Note that the axes can have different scales.
+.PP
+To display a different axis, you invoke one of the following
+components: \fBxaxis\fR, \fByaxis\fR, \fBx2axis\fR, and \fBy2axis\fR.
+The \fBuse\fR operation designates the axis to be drawn in the
+corresponding margin: \fBxaxis\fR in the bottom, \fByaxis\fR in the left, 
+\fBx2axis\fR in the top, and \fBy2axis\fR in the right.
+.CS
+# Display the axis temperature in the left margin.
+\&.b yaxis use temperature
+.CE
+.PP
+You can configure axes in many ways. The axis scale can be linear or
+logarithmic.  The values along the axis can either monotonically
+increase or decrease.  If you need custom tick labels, you can specify
+a Tcl procedure to format the label any way you wish.  You can
+control how ticks are drawn, by changing the major tick interval
+or the number of minor ticks.  You can define non-uniform tick intervals,
+such as for time-series plots.
+.PP
+.TP
+\fIpathName \fBaxis \fBcget \fIaxisName \fIoption\fR
+Returns the current value of the option given by \fIoption\fR for
+\fIaxisName\fR.  \fIOption\fR may be any option described below
+for the axis \fBconfigure\fR operation.
+.TP
+\fIpathName \fBaxis \fBconfigure \fIaxisName \fR?\fIaxisName\fR?... ?\fIoption value\fR?...
+Queries or modifies the configuration options of \fIaxisName\fR.
+Several axes can be changed.  If \fIoption\fR isn't specified, a list
+describing all the current options for \fIaxisName\fR is returned.  If
+\fIoption\fR is specified, but not \fIvalue\fR, then a list describing
+\fIoption\fR is returned.  If one or more \fIoption\fR and \fIvalue\fR
+pairs are specified, then for each pair, the axis option \fIoption\fR
+is set to \fIvalue\fR.  The following options are valid for axes.
+.RS
+.TP
+\fB\-autorange \fIrange\fR 
+Sets the range of values for the axis to \fIrange\fR.  The axis limits
+are automatically reset to display the most recent data points in this range.  
+If \fIrange\fR is 0.0, the range is
+determined from the limits of the data.  If \fB\-min\fR or \fB-max\fR
+are specified, they override this option.  The default is \f(CW0.0\fR.
+.TP
+\fB\-color \fIcolor\fR
+Sets the color of the axis and tick labels.
+The default is \f(CWblack\fR.
+.TP
+\fB\-command \fIprefix\fR
+Specifies a Tcl command to be invoked when formatting the axis tick
+labels. \fIPrefix\fR is a string containing the name of a Tcl proc and
+any extra arguments for the procedure.  This command is invoked for each
+major tick on the axis.  Two additional arguments are passed to the
+procedure: the pathname of the widget and the current the numeric
+value of the tick.  The procedure returns the formatted tick label.  If
+\f(CW""\fR is returned, no label will appear next to the tick.  You can
+get the standard tick labels again by setting \fIprefix\fR to
+\f(CW""\fR.  The default is \f(CW""\fR.
+.sp 1
+Please note that this procedure is invoked while the bar chart is redrawn.
+You may query the widget's configuration options.  But do not reset
+options, because this can have unexpected results.
+.TP
+\fB\-descending \fIboolean\fR 
+Indicates whether the values along the axis are monotonically increasing or
+decreasing.  If \fIboolean\fR is true, the axis values will be
+decreasing.  The default is \f(CW0\fR.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether the axis is displayed. 
+.TP
+\fB\-justify \fIjustify\fR
+Specifies how the axis title should be justified.  This matters only
+when the axis title contains more than one line of text. \fIJustify\fR
+must be \f(CWleft\fR, \f(CWright\fR, or \f(CWcenter\fR.  The default is
+\f(CWcenter\fR.
+.TP
+\fB\-limits \fIformatStr\fR
+Specifies a printf-like description to format the minimum and maximum
+limits of the axis.  The limits are displayed at the top/bottom or
+left/right sides of the plotting area.  \fIFormatStr\fR is a list of
+one or two format descriptions.  If one description is supplied, both
+the minimum and maximum limits are formatted in the same way.  If two,
+the first designates the format for the minimum limit, the second for
+the maximum.  If \f(CW""\fR is given as either description, then 
+the that limit will not be displayed.  The default is \f(CW""\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of the axis and tick lines.  The default is \f(CW1\fR
+pixel.
+.TP
+\fB\-logscale \fIboolean\fR
+Indicates whether the scale of the axis is logarithmic or linear.  If
+\fIboolean\fR is true, the axis is logarithmic.  The default scale is
+linear.
+.TP
+\fB\-loose \fIboolean\fR
+Indicates whether the limits of the axis should fit the data points tightly,
+at the outermost data points, or loosely, at the outer tick intervals.
+This is relevant only when the axis limit is automatically calculated.
+If \fIboolean\fR is true, the axis range is "loose".
+The default is \f(CW0\fR.
+.TP
+\fB\-majorticks \fImajorList\fR
+Specifies where to display major axis ticks.  You can use this option
+to display ticks at non-uniform intervals.  \fIMajorList\fR is a list
+of axis coordinates designating the location of major ticks.  No
+minor ticks are drawn.  If \fImajorList\fR is \f(CW""\fR, 
+major ticks will be automatically computed. The default is \f(CW""\fR.
+.TP
+\fB\-max \fIvalue\fR
+Sets the maximum limit of \fIaxisName\fR.  Any data point greater 
+than \fIvalue\fR is not displayed.  If \fIvalue\fR is \f(CW""\fR, 
+the maximum limit is calculated using the largest data value.
+The default is \f(CW""\fR.
+.TP
+\fB\-min \fIvalue\fR
+Sets the minimum limit of \fIaxisName\fR. Any data point less than 
+\fIvalue\fR is not displayed.  If \fIvalue\fR is \f(CW""\fR,
+the minimum limit is calculated using the smallest data value.
+The default is \f(CW""\fR.
+.TP
+\fB\-minorticks \fIminorList\fR
+Specifies where to display minor axis ticks.  You can use this option
+to display minor ticks at non-uniform intervals. \fIMinorList\fR is a
+list of real values, ranging from 0.0 to 1.0, designating the placement of
+a minor tick.  No minor ticks are drawn if the \fB\-majortick\fR
+option is also set.  If \fIminorList\fR is \f(CW""\fR, minor ticks will
+be automatically computed. The default is \f(CW""\fR.
+.TP
+\fB\-rotate \fItheta\fR
+Specifies the how many degrees to rotate the axis tick labels.
+\fITheta\fR is a real value representing the number of degrees
+to rotate the tick labels.  The default is \f(CW0.0\fR degrees.
+.TP
+\fB\-shiftby \fIvalue\fR
+Specifies how much to automatically shift the range of the axis.
+When the new data exceeds the current axis maximum, the maximum
+is increased in increments of \fIvalue\fR.  You can use this
+option to prevent the axis limits from being recomputed
+at each new time point. If \fIvalue\fR is 0.0, then no automatic
+shifting is down. The default is \f(CW0.0\fR.
+.TP
+\fB\-showticks \fIboolean\fR
+Indicates whether axis ticks should be drawn. If \fIboolean\fR is
+true, ticks are drawn.  If false, only the
+axis line is drawn. The default is \f(CW1\fR.
+.TP
+\fB\-stepsize \fIvalue\fR
+Specifies the interval between major axis ticks.  If \fIvalue\fR isn't
+a valid interval (must be less than the axis range), 
+the request is ignored and the step size is automatically calculated.
+.TP
+\fB\-subdivisions \fInumber\fR 
+Indicates how many minor axis ticks are
+to be drawn.  For example, if \fInumber\fR is two, only one minor
+tick is drawn.  If \fInumber\fR is one, no minor ticks are
+displayed.  The default is \f(CW2\fR.
+.TP
+\fB\-tickfont \fIfontName\fR 
+Specifies the font for axis tick labels. The default is
+\f(CW*-Courier-Bold-R-Normal-*-100-*\fR.
+.TP
+\fB\-ticklength \fIpixels\fR
+Sets the length of major and minor ticks (minor ticks are half the
+length of major ticks). If \fIpixels\fR is less than zero, the axis
+will be inverted with ticks drawn pointing towards the plot.  The
+default is \f(CW0.1i\fR.
+.TP
+\fB\-title \fItext\fR
+Sets the title of the axis. If \fItext\fR is 
+\f(CW""\fR, no axis title will be displayed.  
+.TP
+\fB\-titlecolor \fIcolor\fR
+Sets the color of the axis title. The default is \f(CWblack\fR.
+.TP
+\fB\-titlefont \fIfontName\fR 
+Specifies the font for axis title. The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-14-140-*\fR.
+.PP
+Axis configuration options may be also be set by the \fBoption\fR
+command.  The resource class is \f(CWAxis\fR.  The resource names
+are the names of the axes (such as \f(CWx\fR or \f(CWx2\fR).
+.CS
+option add *Barchart.Axis.Color  blue
+option add *Barchart.x.LogScale  true
+option add *Barchart.x2.LogScale false
+.CE
+.RE
+.TP
+\fIpathName \fBaxis \fBcreate \fIaxisName \fR?\fIoption value\fR?...
+Creates a new axis by the name \fIaxisName\fR.  No axis by the same
+name can already exist. \fIOption\fR and \fIvalue\fR are described 
+in above in the axis \fBconfigure\fR operation.
+.TP
+\fIpathName \fBaxis \fBdelete \fR?\fIaxisName\fR?...
+Deletes the named axes. An axis is not really
+deleted until it is not longer in use, so it's safe to delete
+axes mapped to elements.
+.TP
+\fIpathName \fBaxis invtransform \fIaxisName value\fR
+Performs the inverse transformation, changing the screen-coordinate
+\fIvalue\fR to a graph-coordinate, mapping the value mapped to
+\fIaxisName\fR.  Returns the graph-coordinate.
+.TP
+\fIpathName \fBaxis limits \fIaxisName\fR
+Returns a list of the minimum and maximum limits for \fIaxisName\fR.  The order
+of the list is \f(CWmin max\fR.
+.TP
+\fIpathName \fBaxis names \fR?\fIpattern\fR?...
+Returns a list of axes matching zero or more patterns.  If no
+\fIpattern\fR argument is give, the names of all axes are returned.
+.TP
+\fIpathName \fBaxis transform \fIaxisName value\fR
+Transforms the coordinate \fIvalue\fR to a screen-coordinate by mapping
+the it to \fIaxisName\fR.  Returns the transformed screen-coordinate.
+.PP
+Only four axes can be displayed simultaneously.  By default, they are
+\f(CWx\fR, \f(CWy\fR, \f(CWx2\fR, and \f(CWy2\fR.  You can swap in a different
+axis with \fBuse\fR operation of the special axis components:
+\fBxaxis\fR, \fBx2axis\fR, \fByaxis\fR, and \fBy2axis\fR.
+.CS
+\&.g create axis temp
+\&.g create axis time
+\&...
+\&.g xaxis use temp
+\&.g yaxis use time
+.CE
+Only the axes specified for use are displayed on the screen.
+.PP
+The \fBxaxis\fR, \fBx2axis\fR, \fByaxis\fR, and \fBy2axis\fR
+components operate on an axis location rather than a specific axis
+like the more general \fBaxis\fR component does.  The \fBxaxis\fR
+component manages the X-axis located in the bottom margin (whatever
+axis that happens to be).  Likewise, \fByaxis\fR uses the Y-axis in
+the left margin, \fBx2axis\fR the top X-axis, and \fBy2axis\fR the
+right Y-axis.
+.PP
+They implicitly control the axis that is currently using to that
+location.  By default, \fBxaxis\fR uses the \f(CWx\fR axis, \fByaxis\fR
+uses \f(CWy\fR, \fBx2axis\fR uses \f(CWx2\fR, and \fBy2axis\fR uses
+\f(CWy2\fR.  These components can be more convenient to use than always
+determining what axes are current being displayed by the graph.
+.PP
+The following operations are available for axes. They mirror exactly
+the operations of the \fBaxis\fR component.  The \fIaxis\fR argument
+must be \fBxaxis\fR, \fBx2axis\fR, \fByaxis\fR, or \fBy2axis\fR.
+.TP
+\fIpathName \fIaxis \fBcget \fIoption\fR
+.TP
+\fIpathName \fIaxis \fBconfigure \fR?\fIoption value\fR?...
+.TP
+\fIpathName \fIaxis\fB invtransform \fIvalue\fR
+.TP
+\fIpathName \fIaxis \fBlimits\fR
+.TP
+\fIpathName \fIaxis\fB transform \fIvalue\fR
+.TP
+\fIpathName \fIaxis\fB use \fR?\fIaxisName\fR?  
+Designates the axis \fIaxisName\fR is to be displayed at this
+location.  \fIAxisName\fR can not be already in use at another location.  
+This command returns the name of the axis currently using this location.
+.SS "CROSSHAIRS COMPONENT"
+Cross hairs consist of two intersecting lines (one vertical and one horizontal)
+drawn completely across the plotting area.  They are used to position
+the mouse in relation to the coordinate axes.  Cross hairs differ from line
+markers in that they are implemented using XOR drawing primitives.
+This means that they can be quickly drawn and erased without redrawing
+the entire widget.
+.PP
+The following operations are available for cross hairs:
+.TP
+\fIpathName \fBcrosshairs cget \fIoption\fR
+Returns the current value of the cross hairs configuration option
+given by \fIoption\fR.  \fIOption\fR may be any option
+described below for the cross hairs \fBconfigure\fR operation.
+.TP
+\fIpathName \fBcrosshairs configure \fR?\fIoption value\fR?...  
+Queries or modifies the configuration options of the cross hairs.  If
+\fIoption\fR isn't specified, a list describing all the current
+options for the cross hairs is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is returned.
+If one or more \fIoption\fR and \fIvalue\fR pairs are specified, then
+for each pair, the cross hairs option \fIoption\fR is set to
+\fIvalue\fR.
+The following options are available for cross hairs.
+.RS
+.TP
+\fB\-color \fIcolor\fR 
+Sets the color of the cross hairs.  The default is \f(CWblack\fR.
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the cross hairs. \fIDashList\fR is a list of up
+to 11 numbers that alternately represent the lengths of the dashes
+and gaps on the cross hair lines.  Each number must be between 1 and
+255.  If \fIdashList\fR is \f(CW""\fR, the cross hairs will be solid
+lines.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether cross hairs are drawn. If \fIboolean\fR is true,
+cross hairs are not drawn.  The default is \f(CWyes\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Set the width of the cross hair lines.  The default is \f(CW1\fR.
+.TP
+\fB\-position \fIpos\fR 
+Specifies the screen position where the cross hairs intersect.
+\fIPos\fR must be in the form "\fI@x,y\fR", where \fIx\fR and \fIy\fR
+are the window coordinates of the intersection.
+.PP
+Cross hairs configuration options may be also be set by the
+\fBoption\fR command.  The resource name and class are
+\f(CWcrosshairs\fR and \f(CWCrosshairs\fR respectively.
+.CS
+option add *Barchart.Crosshairs.LineWidth 2
+option add *Barchart.Crosshairs.Color     red
+.CE
+.RE
+.TP
+\fIpathName \fBcrosshairs off\fR
+Turns off the cross hairs. 
+.TP
+\fIpathName \fBcrosshairs on\fR
+Turns on the display of the cross hairs.
+.TP
+\fIpathName \fBcrosshairs toggle\fR 
+Toggles the current state of the cross hairs, alternately mapping and
+unmapping the cross hairs.
+.SH "ELEMENTS"
+A data element represents a set of data.  It contains x and y vectors
+which are the coordinates of the data points.  Elements are displayed
+as bars where the length of the bar is proportional to the ordinate of
+the data point.  Elements also control the appearance of the data,
+such as the color, stipple, relief, etc.
+.PP
+When new data elements are created, they are automatically added to a
+list of displayed elements.   The display list controls what elements
+are drawn and in what order.  
+.PP
+The following operations are available for elements.
+.TP
+\fIpathName \fBelement activate \fIelemName \fR?\fIindex\fR?...
+Specifies the data points of element \fIelemName\fR to be drawn
+using active foreground and background colors.  \fIElemName\fR is the
+name of the element and \fIindex\fR is a number representing the index
+of the data point. If no indices are present then all data points
+become active.
+.TP
+\fIpathName \fBelement bind \fItagName\fR ?\fIsequence\fR?  ?\fIcommand\fR? 
+Associates \fIcommand\fR with \fItagName\fR such that whenever the
+event sequence given by \fIsequence\fR occurs for an element with this
+tag, \fIcommand\fR will be invoked.  The syntax is similar to the 
+\fBbind\fR command except that it operates on graph elements, rather 
+than widgets. See the \fBbind\fR manual entry for
+complete details on \fIsequence\fR and the substitutions performed on 
+\fIcommand\fR before invoking it.  
+.sp
+If all arguments are specified then a new binding is created, replacing 
+any existing binding for the same \fIsequence\fR and \fItagName\fR.
+If the first character of \fIcommand\fR is \f(CW+\fR then \fIcommand\fR 
+augments an existing binding rather than replacing it. 
+If no \fIcommand\fR argument is provided then the command currently
+associated with \fItagName\fR and \fIsequence\fR (it's an error occurs 
+if there's no such binding) is returned.  If both \fIcommand\fR and 
+\fIsequence\fR are missing then a list of all the event sequences for 
+which bindings have been defined for \fItagName\fR. 
+.TP
+\fIpathName \fBelement cget \fIelemName \fIoption\fR
+Returns the current value of the element configuration option given by 
+\fIoption\fR.  \fIOption\fR may be any of the options described below
+for the element \fBconfigure\fR operation.
+.TP
+\fIpathName \fBelement closest \fIx y\fR ?\fIoption value\fR?... ?\fIelemName\fR?...
+Finds the data point representing the bar closest to the window
+coordinates \fIx\fR and \fIy\fR in the element \fIelemName\fR.
+\fIElemName\fR is the name of an element, which must be currently displayed.  
+If no elements are specified, then all displayed elements are searched.  It
+returns a key-value list containing the name of the closest element, 
+the index of its closest point, and the graph-coordinates of the
+point. If no data point within the threshold distance can be found,
+\f(CW""\fR is returned.  The following \fIoption\fR-\fIvalue\fR pairs
+are available.
+.RS
+.TP
+\fB\-halo \fIpixels\fR
+Specifies a threshold distance where selected data points are ignored.
+\fIPixels\fR is a valid screen distance, such as \f(CW2\fR or \f(CW1.2i\fR.
+If this option isn't specified, then it defaults to the value of the
+\fBbarchart\fR's \fB\-halo\fR option.
+.RE
+.TP
+\fIpathName \fBelement configure \fIelemName \fR?\fIelemName\fR... ?\fIoption value\fR?...
+Queries or modifies the configuration options for elements.  Several
+elements can be modified at the same time. If \fIoption\fR isn't
+specified, a list describing all the current options for
+\fIelemName\fR is returned.  If \fIoption\fR is specified, but not
+\fIvalue\fR, then a list describing the option \fIoption\fR is
+returned.  If one or more \fIoption\fR and \fIvalue\fR pairs are
+specified, then for each pair, the element option \fIoption\fR is set
+to \fIvalue\fR.  The following options are valid for elements.
+.RS
+.TP
+\fB\-activepen \fIpenName\fR
+Specifies pen to use to draw active element.  If \fIpenName\fR is
+\f(CW""\fR, no active elements will be drawn.  The default is 
+\f(CWactiveLine\fR.
+.TP
+\fB\-bindtags \fItagList\fR
+Specifies the binding tags for the element.  \fITagList\fR is a list
+of binding tag names.  The tags and their order will determine how
+events for elements.  Each tag in the list matching the current event
+sequence will have its Tcl command executed.  Implicitly the name of
+the element is always the first tag in the list.  The default value is
+\f(CWall\fR.
+.TP
+\fB\-background \fIcolor\fR
+Sets the the color of the border around each bar.  The default is
+\f(CWwhite\fR.
+.TP
+\fB\-barwidth \fIvalue\fR 
+Specifies the width the bars drawn for the element.  \fIValue\fR is
+the width in X-coordinates.  If this option isn't
+specified, the width of each bar is the value of the widget's
+\fB\-barwidth\fR option.
+.TP
+\fB\-baseline \fIvalue\fR 
+Specifies the baseline of the bar segments.  This affects how bars are 
+drawn since bars are drawn from their respective y-coordinate the 
+baseline. By default the baseline is \f(CW0.0\fR.  
+.TP
+\fB\-borderwidth \fIpixels\fR
+Sets the border width of the 3-D border drawn around the outside of
+each bar.  The \fB\-relief\fR option determines if such a border is
+drawn.  \fIPixels\fR must be a valid screen distance like \f(CW2\fR or
+\f(CW0.25i\fR. The default is \f(CW2\fR.
+.TP
+\fB\-data \fIcoordList\fR
+Specifies the X\-Y coordinates of the data.  \fICoordList\fR is a
+list of numeric expressions representing the X\-Y coordinate pairs
+of each data point.
+.TP
+\fB\-foreground \fIcolor\fR 
+Sets the color of the interior of the bars.  
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether the element is displayed.  The default is \f(CWno\fR.
+.TP
+\fB\-label \fItext\fR
+Sets the element's label in the legend.  If \fItext\fR
+is \f(CW""\fR, the element will have no entry in the legend.
+The default label is the element's name.
+.TP
+\fB\-mapx \fIxAxis\fR
+Selects the X\-axis to map the element's X\-coordinates onto.
+\fIXAxis\fR must be the name of an axis.  The default is \f(CWx\fR.
+.TP
+\fB\-mapy \fIyAxis\fR
+Selects the Y\-axis to map the element's Y\-coordinates onto.
+\fIYAxis\fR must be the name of an axis. The default is \f(CWy\fR.
+.TP
+\fB\-relief \fIstring\fR
+Specifies the 3-D effect desired for bars.  \fIRelief\fR indicates how
+the interior of the bar should appear relative to the surface of the
+chart; for example, \f(CWraised\fR means the bar should appear to
+protrude from the surface of the plotting area.  The default is
+\f(CWraised\fR.
+.TP
+\fB\-stipple \fIbitmap\fR
+Specifies a stipple pattern with which to draw the bars.  If
+\fIbitmap\fR is \f(CW""\fR, then the bar is drawn in a solid fashion.
+.TP
+\fB\-xdata \fIxVector\fR 
+Specifies the x-coordinate vector of the data.
+\fIXVector\fR is the name of a BLT vector or a
+list of numeric expressions.  
+.TP
+\fB\-ydata \fIyVector\fR 
+Specifies the y-coordinate vector of the data.
+\fIYVector\fR is the name of a BLT vector or a list of
+numeric expressions.  
+.PP
+Element configuration options may also be set by the 
+\fBoption\fR command.  The resource names  in the option database 
+are prefixed by \f(CWelem\fR.
+.CS
+option add *Barchart.Element.background blue
+.CE
+.RE
+.TP
+\fIpathName \fBelement create \fIelemName\fR ?\fIoption value\fR?...
+Creates a new element \fIelemName\fR.  Element
+names must be unique, so an element \fIelemName\fR may not already
+exist.  If additional arguments are present, they specify any of the
+element options valid for element \fBconfigure\fR operation.
+.TP
+\fIpathName \fBelement deactivate \fIpattern\fR...
+Deactivates all the elements matching \fIpattern\fR for the graph.  
+Elements whose names match any of the patterns given are redrawn 
+using their normal colors.  
+.TP
+\fIpathName \fBelement delete\fR ?\fIpattern\fR?...
+Deletes all the elements matching \fIpattern\fR for the graph.  
+Elements whose names match any of the patterns given are deleted. 
+The graph will be redrawn without the deleted elements.  
+.TP
+\fIpathName \fBelement exists \fIelemName\fR
+Returns \f(CW1\fR if an element \fIelemName\fR currently exists and
+\f(CW0\fR otherwise.
+.TP
+\fIpathName \fBelement names \fR?\fIpattern\fR?...  
+Returns the elements matching one or more pattern.  If no
+\fIpattern\fR is given, the names of all elements is returned.
+.TP
+\fIpathName \fBelement show\fR ?\fInameList\fR?  
+Queries or modifies the element display list.  The element display
+list designates the elements drawn and in what
+order. \fINameList\fR is a list of elements to be displayed in the
+order they are named.  If there is no \fInameList\fR argument,
+the current display list is returned.
+.TP
+\fIpathName \fBelement type\fR \fIelemName\fR
+Returns the type of \fIelemName\fR. 
+If the element is a bar element, the commands returns the string
+\f(CW"bar"\fR, otherwise it returns \f(CW"line"\fR.
+.CE
+.SS "GRID COMPONENT"
+Grid lines extend from the major and minor ticks of each axis
+horizontally or vertically across the plotting area.  The following
+operations are available for grid lines.
+.TP
+\fIpathName \fBgrid cget \fIoption\fR
+Returns the current value of the grid line configuration option given by 
+\fIoption\fR.  \fIOption\fR may be any option described below
+for the grid \fBconfigure\fR operation.
+.TP
+\fIpathName \fBgrid configure\fR ?\fIoption value\fR?...
+Queries or modifies the configuration options for grid lines.  If
+\fIoption\fR isn't specified, a list describing all the current
+grid options for \fIpathName\fR is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is
+returned.  If one or more \fIoption\fR and \fIvalue\fR pairs are
+specified, then for each pair, the grid line option \fIoption\fR is set to
+\fIvalue\fR.  The following options are valid for grid lines.
+.RS
+.TP
+\fB\-color \fIcolor\fR 
+Sets the color of the grid lines.  The default is \f(CWblack\fR.
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the grid lines. \fIDashList\fR is a list of up
+to 11 numbers that alternately represent the lengths of the dashes
+and gaps on the grid lines.  Each number must be between 1 and 255.
+If \fIdashList\fR is \f(CW""\fR, the grid will be solid lines.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether the grid should be drawn. If \fIboolean\fR
+is true, grid lines are not shown. The default is \f(CWyes\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of grid lines.  The default width is \f(CW1\fR.
+.TP
+\fB\-mapx \fIxAxis\fR
+Specifies the X\-axis to display grid lines.  \fIXAxis\fR
+must be the name of an axis or \f(CW""\fR for no grid lines.  
+The default is \f(CW""\fR.
+.TP
+\fB\-mapy \fIyAxis\fR
+Specifies the Y\-axis to display grid lines.  \fIYAxis\fR
+must be the name of an axis or \f(CW""\fR for no grid lines. 
+The default is \f(CWy\fR.
+.TP
+\fB\-minor \fIboolean\fR
+Indicates whether the grid lines should be drawn for minor ticks. 
+If \fIboolean\fR is true, the lines will appear at
+minor tick intervals.  The default is \f(CW1\fR.
+.PP
+Grid configuration options may also be set by the 
+\fBoption\fR command.  The resource name and class are \f(CWgrid\fR and 
+\f(CWGrid\fR respectively. 
+.CS
+option add *Barchart.grid.LineWidth 2
+option add *Barchart.Grid.Color     black
+.CE
+.RE
+.TP
+\fIpathName \fBgrid off\fR
+Turns off the display the grid lines.
+.TP
+\fIpathName \fBgrid on\fR
+Turns on the display the grid lines.
+.TP
+\fIpathName \fBgrid toggle\fR
+Toggles the display of the grid.  
+.SS "LEGEND COMPONENT"
+The legend displays a list of the data elements.  Each entry consists
+of the element's symbol and label.  The legend can appear in any
+margin (the default location is in the right margin).  It
+can also be positioned anywhere within the plotting area.
+.PP
+The following operations are valid for the legend.
+.TP
+\fIpathName \fBlegend activate \fIpattern\fR...
+Selects legend entries to be drawn using the active legend colors and relief.
+All entries whose element names match \fIpattern\fR  are selected.  To
+be selected, the element name must match only one \fIpattern\fR. 
+.TP
+\fIpathName \fBlegend bind \fItagName\fR ?\fIsequence\fR?  ?\fIcommand\fR? 
+Associates \fIcommand\fR with \fItagName\fR such that whenever the
+event sequence given by \fIsequence\fR occurs for a legend entry with this
+tag, \fIcommand\fR will be invoked.  Implicitly the element names
+in the entry are tags.  The syntax is similar to the 
+\fBbind\fR command except that it operates on legend entries, rather 
+than widgets. See the \fBbind\fR manual entry for
+complete details on \fIsequence\fR and the substitutions performed on 
+\fIcommand\fR before invoking it.  
+.sp
+If all arguments are specified then a new binding is created, replacing 
+any existing binding for the same \fIsequence\fR and \fItagName\fR.
+If the first character of \fIcommand\fR is \f(CW+\fR then \fIcommand\fR 
+augments an existing binding rather than replacing it. 
+If no \fIcommand\fR argument is provided then the command currently
+associated with \fItagName\fR and \fIsequence\fR (it's an error occurs 
+if there's no such binding) is returned.  If both \fIcommand\fR and 
+\fIsequence\fR are missing then a list of all the event sequences for 
+which bindings have been defined for \fItagName\fR. 
+.TP
+\fIpathName \fBlegend cget \fIoption\fR
+Returns the current value of a legend configuration option.
+\fIOption\fR may be any option described below in the
+legend \fBconfigure\fR operation.
+.TP
+\fIpathName \fBlegend configure \fR?\fIoption value\fR?...
+Queries or modifies the configuration options for the legend.  If
+\fIoption\fR isn't specified, a list describing the current
+legend options for \fIpathName\fR is returned.  If \fIoption\fR is
+specified, but not \fIvalue\fR, then a list describing \fIoption\fR is
+returned.  If one or more \fIoption\fR and \fIvalue\fR pairs are
+specified, then for each pair, the legend option \fIoption\fR is set
+to \fIvalue\fR.  The following options are valid for the legend.
+.RS
+.TP
+\fB\-activebackground \fIcolor\fR
+Sets the background color for active legend entries.  All legend
+entries marked active (see the legend \fBactivate\fR operation) are
+drawn using this background color.
+.TP
+\fB\-activeborderwidth \fIpixels\fR
+Sets the width of the 3-D border around the outside edge of the active legend
+entries.  The default is \f(CW2\fR.
+.TP
+\fB\-activeforeground \fIcolor\fR
+Sets the foreground color for active legend entries.  All legend
+entries marked as active (see the legend \fBactivate\fR operation) are
+drawn using this foreground color.
+.TP
+\fB\-activerelief \fIrelief\fR 
+Specifies the 3-D effect desired for active legend entries.
+\fIRelief\fR denotes how the interior of the entry should appear
+relative to the legend; for example, \f(CWraised\fR means the entry
+should appear to protrude from the legend, relative to the surface of
+the legend.  The default is \f(CWflat\fR.
+.TP
+\fB\-anchor \fIanchor\fR
+Tells how to position the legend relative to the positioning point for
+the legend.  This is dependent on the value of the \fB\-position\fR
+option.  The default is \f(CWcenter\fR.
+.RS
+.TP 1.25i
+\f(CWleft\fR or \f(CWright\fR
+The anchor describes how to position the legend vertically.  
+.TP
+\f(CWtop\fR or \f(CWbottom\fR
+The anchor describes how to position the legend horizontally.  
+.TP
+\f(CW@x,y\fR
+The anchor specifies how to position the legend relative to the
+positioning point. For example, if \fIanchor\fR is \f(CWcenter\fR then
+the legend is centered on the point; if \fIanchor\fR is \f(CWn\fR then
+the legend will be drawn such that the top center point of the
+rectangular region occupied by the legend will be at the positioning
+point.
+.TP
+\f(CWplotarea\fR
+The anchor specifies how to position the legend relative to the
+plotting area. For example, if \fIanchor\fR is \f(CWcenter\fR then the
+legend is centered in the plotting area; if \fIanchor\fR is \f(CWne\fR
+then the legend will be drawn such that occupies the upper right
+corner of the plotting area.
+.RE
+.TP
+\fB\-background \fIcolor\fR
+Sets the background color of the legend. If \fIcolor\fR is \f(CW""\fR,
+the legend background with be transparent.
+.TP
+\fB\-bindtags \fItagList\fR
+Specifies the binding tags for legend entries.  \fITagList\fR is a list
+of binding tag names.  The tags and their order will determine how
+events for legend entries.  Each tag in the list matching the current 
+event sequence will have its Tcl command executed. The default value 
+is \f(CWall\fR.
+.TP
+\fB\-borderwidth \fIpixels\fR
+Sets the width of the 3-D border around the outside edge of the legend (if
+such border is being drawn; the \fBrelief\fR option determines this).
+The default is \f(CW2\fR pixels.
+.TP
+\fB\-font \fIfontName\fR 
+\fIFontName\fR specifies a font to use when drawing the labels of each
+element into the legend.  The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-12-120-*\fR.
+.TP
+\fB\-foreground \fIcolor\fR 
+Sets the foreground color of the text drawn for the element's label.
+The default is \f(CWblack\fR.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether the legend should be displayed. If \fIboolean\fR is
+true, the legend will not be draw.  The default is \f(CWno\fR.
+.TP
+\fB\-ipadx \fIpad\fR 
+Sets the amount of internal padding to be added to the width of each
+legend entry.  \fIPad\fR can be a list of one or two screen distances.  If
+\fIpad\fR has two elements, the left side of the legend entry is
+padded by the first distance and the right side by the second.  If
+\fIpad\fR is just one distance, both the left and right sides are padded
+evenly.  The default is \f(CW2\fR.
+.TP
+\fB\-ipady \fIpad\fR
+Sets an amount of internal padding to be added to the height of each
+legend entry.  \fIPad\fR can be a list of one or two screen distances.  If
+\fIpad\fR has two elements, the top of the entry is padded by the
+first distance and the bottom by the second.  If \fIpad\fR is just
+one distance, both the top and bottom of the entry are padded evenly.
+The default is \f(CW2\fR.
+.TP
+\fB\-padx \fIpad\fR
+Sets the padding to the left and right exteriors of the legend.
+\fIPad\fR can be a list of one or two screen distances.  If \fIpad\fR
+has two elements, the left side of the legend is padded by the first
+distance and the right side by the second.  If \fIpad\fR has just one
+distance, both the left and right sides are padded evenly.  The
+default is \f(CW4\fR.
+.TP
+\fB\-pady \fIpad\fR
+Sets the padding above and below the legend.  \fIPad\fR can be a list
+of one or two screen distances.  If \fIpad\fR has two elements, the area above
+the legend is padded by the first distance and the area below by the
+second.  If \fIpad\fR is just one distance, both the top and
+bottom areas are padded evenly.  The default is \f(CW0\fR.
+.TP
+\fB\-position \fIpos\fR
+Specifies where the legend is drawn. The
+\fB\-anchor\fR option also affects where the legend is positioned.  If
+\fIpos\fR is \f(CWleft\fR, \f(CWleft\fR, \f(CWtop\fR, or \f(CWbottom\fR, the
+legend is drawn in the specified margin.  If \fIpos\fR is
+\f(CWplotarea\fR, then the legend is drawn inside the plotting area at a
+particular anchor.  If \fIpos\fR is in the form "\fI@x,y\fR", where
+\fIx\fR and \fIy\fR are the window coordinates, the legend is drawn in
+the plotting area at the specified coordinates.  The default is
+\f(CWright\fR.
+.TP
+\fB\-raised \fIboolean\fR
+Indicates whether the legend is above or below the data elements.  This
+matters only if the legend is in the plotting area.  If \fIboolean\fR
+is true, the legend will be drawn on top of any elements that may
+overlap it. The default is \f(CWno\fR.
+.TP
+\fB\-relief \fIrelief\fR
+Specifies the 3-D effect for the border around the legend.
+\fIRelief\fR specifies how the interior of the legend should appear
+relative to the bar chart; for example, \f(CWraised\fR means the legend
+should appear to protrude from the bar chart, relative to the surface of
+the bar chart.  The default is \f(CWsunken\fR.
+.PP
+Legend configuration options may also be set by the \fBoption\fR
+command.  The resource name and class are \f(CWlegend\fR and
+\f(CWLegend\fR respectively.
+.CS
+option add *Barchart.legend.Foreground blue
+option add *Barchart.Legend.Relief     raised
+.CE
+.RE
+.TP
+\fIpathName \fBlegend deactivate \fIpattern\fR...
+Selects legend entries to be drawn using the normal legend colors and
+relief.  All entries whose element names match \fIpattern\fR are
+selected.  To be selected, the element name must match only one
+\fIpattern\fR.
+.TP
+\fIpathName \fBlegend get \fIpos\fR
+Returns the name of the element whose entry is at the screen position
+\fIpos\fR in the legend.  \fIPos\fR must be in the form "\fI@x,y\fR",
+where \fIx\fR and \fIy\fR are window coordinates.  If the given
+coordinates do not lie over a legend entry, \f(CW""\fR is returned.
+.SS "PEN COMPONENTS"
+Pens define attributes for elements.
+Pens mirror the configuration options of data elements that pertain to
+how symbols and lines are drawn.  Data elements use pens to determine
+how they are drawn.  A data element may use several pens at once.  In
+this case, the pen used for a particular data point is determined from
+each element's weight vector (see the element's \fB\-weight\fR and
+\fB\-style\fR options).
+.PP
+One pen, called \f(CWactiveBar\fR, is automatically created.
+It's used as the default active pen for elements. So you can change
+the active attributes for all elements by simply reconfiguring this
+pen.
+.CS
+\&.g pen configure "activeBar" -fg green -bg green4
+.CE
+You can create and use several pens. To create a pen, invoke
+the pen component and its create operation.
+.CS
+\&.g pen create myPen
+.CE
+You map pens to a data element using either the element's 
+\fB\-pen\fR or \fB\-activepen\fR options.
+.CS
+\&.g element create "e1" -xdata $x -ydata $tempData \\
+    -pen myPen
+.CE
+An element can use several pens at once. This is done by specifying
+the name of the pen in the element's style list (see the
+\fB\-styles\fR option).
+.CS
+\&.g element configure "e1" -styles { myPen 2.0 3.0 }
+.CE
+This says that any data point with a weight between 2.0 and 3.0
+is to be drawn using the pen \f(CWmyPen\fR.  All other points
+are drawn with the element's default attributes.
+.PP
+The following operations are available for pen components.
+.PP
+.TP
+\fIpathName \fBpen \fBcget \fIpenName \fIoption\fR
+Returns the current value of the option given by \fIoption\fR for
+\fIpenName\fR.  \fIOption\fR may be any option described below
+for the pen \fBconfigure\fR operation.
+.TP
+\fIpathName \fBpen \fBconfigure \fIpenName \fR?\fIpenName\fR... ?\fIoption value\fR?...
+Queries or modifies the configuration options of
+\fIpenName\fR. Several pens can be modified at once.  If \fIoption\fR
+isn't specified, a list describing the current options for
+\fIpenName\fR is returned.  If \fIoption\fR is specified, but not
+\fIvalue\fR, then a list describing \fIoption\fR is returned.  If one
+or more \fIoption\fR and \fIvalue\fR pairs are specified, then for
+each pair, the pen option \fIoption\fR is set to \fIvalue\fR.  The
+following options are valid for pens.
+.RS
+.TP
+\fB\-background \fIcolor\fR
+Sets the the color of the border around each bar.  The default is
+\f(CWwhite\fR.
+.TP
+\fB\-borderwidth \fIpixels\fR
+Sets the border width of the 3-D border drawn around the outside of
+each bar.  The \fB\-relief\fR option determines if such a border is
+drawn.  \fIPixels\fR must be a valid screen distance like \f(CW2\fR or
+\f(CW0.25i\fR. The default is \f(CW2\fR.
+.TP
+\fB\-foreground \fIcolor\fR 
+Sets the color of the interior of the bars.  
+.TP
+\fB\-relief \fIstring\fR
+Specifies the 3-D effect desired for bars.  \fIRelief\fR indicates how
+the interior of the bar should appear relative to the surface of the
+chart; for example, \f(CWraised\fR means the bar should appear to
+protrude from the bar chart, relative to the surface of the plotting
+area.  The default is \f(CWraised\fR.
+.TP
+\fB\-stipple \fIbitmap\fR
+Specifies a stipple pattern with which to draw the bars.  If
+\fIbitmap\fR is \f(CW""\fR, then the bar is drawn in a solid fashion.
+.TP
+\fB\-type \fIelemType\fR 
+Specifies the type of element the pen is to be used with.
+This option should only be employed when creating the pen.  This
+is for those that wish to mix different types of elements (bars and
+lines) on the same graph.  The default type is "bar".
+.PP
+Pen configuration options may be also be set by the \fBoption\fR
+command.  The resource class is \f(CWPen\fR.  The resource names
+are the names of the pens.
+.CS
+option add *Barchart.Pen.Foreground	   blue
+option add *Barchart.activeBar.foreground  green
+.CE
+.RE
+.TP
+\fIpathName \fBpen \fBcreate \fIpenName \fR?\fIoption value\fR?...
+Creates a new pen by the name \fIpenName\fR.  No pen by the same
+name can already exist. \fIOption\fR and \fIvalue\fR are described 
+in above in the pen \fBconfigure\fR operation.
+.TP
+\fIpathName \fBpen \fBdelete \fR?\fIpenName\fR?...
+Deletes the named pens. A pen is not really
+deleted until it is not longer in use, so it's safe to delete
+pens mapped to elements.
+.TP
+\fIpathName \fBpen names \fR?\fIpattern\fR?...
+Returns a list of pens matching zero or more patterns.  If no
+\fIpattern\fR argument is give, the names of all pens are returned.
+.SS "POSTSCRIPT COMPONENT"
+The barchart can generate encapsulated PostScript output.  There
+are several configuration options you can specify to control how the
+plot will be generated.  You can change the page dimensions and
+borders.  The plot itself can be scaled, centered, or rotated to
+landscape.  The PostScript output can be written directly to a file or
+returned through the interpreter.
+.PP
+The following postscript operations are available.
+.TP
+\fIpathName \fBpostscript cget \fIoption\fR 
+Returns the current value of the postscript option given by
+\fIoption\fR.  \fIOption\fR may be any option described
+below for the postscript \fBconfigure\fR operation.
+.TP
+\fIpathName \fBpostscript configure \fR?\fIoption value\fR?...
+Queries or modifies the configuration options for PostScript
+generation.  If \fIoption\fR isn't specified, a list describing 
+the current postscript options for \fIpathName\fR is returned.  If
+\fIoption\fR is specified, but not \fIvalue\fR, then a list describing
+\fIoption\fR is returned.  If one or more \fIoption\fR and \fIvalue\fR
+pairs are specified, then for each pair, the postscript option
+\fIoption\fR is set to \fIvalue\fR.  The following postscript options
+are available.
+.RS
+.TP
+\fB\-center \fIboolean\fR
+Indicates whether the plot should be centered on the PostScript page.  If
+\fIboolean\fR is false, the plot will be placed in the upper left
+corner of the page.  The default is \f(CW1\fR.
+.TP
+\fB\-colormap \fIvarName\fR
+\fIVarName\fR must be the name of a global array variable that
+specifies a color mapping from the X color name to PostScript.  Each
+element of \fIvarName\fR must consist of PostScript code to set a
+particular color value (e.g. ``\f(CW1.0 1.0 0.0 setrgbcolor\fR'').  When
+generating color information in PostScript, the array variable \fIvarName\fR
+is checked if an element of the name as the color exists. If so, it uses 
+its value as the PostScript
+command to set the color.  If this option hasn't been specified, or if
+there isn't an entry in \fIvarName\fR for a given color, then it uses
+the red, green, and blue intensities from the X color.
+.TP
+\fB\-colormode \fImode\fR
+Specifies how to output color information.  \fIMode\fR must be either
+\f(CWcolor\fR (for full color output), \f(CWgray\fR (convert all colors to
+their gray-scale equivalents) or \f(CWmono\fR (convert foreground colors
+to black and background colors to white).  The default mode is
+\f(CWcolor\fR. 
+.TP
+\fB\-fontmap \fIvarName\fR
+\fIVarName\fR must be the name of a global array variable that
+specifies a font mapping from the X font name to PostScript.  Each
+element of \fIvarName\fR must consist of a Tcl list with one or two
+elements; the name and point size of a PostScript font.
+When outputting PostScript commands for a particular font, the array
+variable \fIvarName\fR is checked to see if an element by the 
+specified font exists.  If there is such an element, then the font
+information contained in that element is used in the PostScript
+output.  (If the point size is omitted from the list, the point size
+of the X font is used).  Otherwise the X font is examined in an
+attempt to guess what PostScript font to use.  This works only for
+fonts whose foundry property is \fIAdobe\fR (such as Times, Helvetica,
+Courier, etc.).  If all of this fails then the font defaults to
+\f(CWHelvetica-Bold\fR.
+.TP
+\fB\-decorations \fIboolean\fR
+Indicates whether PostScript commands to generate color backgrounds and 3-D
+borders will be output.  If \fIboolean\fR is false, the graph will
+background will be white and no 3-D borders will be generated. The
+default is \f(CW1\fR.
+.TP
+\fB\-height \fIpixels\fR
+Sets the height of the plot.  This lets you print the bar chart with a
+height different from the one drawn on the screen.  If
+\fIpixels\fR is 0, the height is the same as the widget's height.
+The default is \f(CW0\fR.
+.TP
+\fB\-landscape \fIboolean\fR
+If \fIboolean\fR is true, this specifies the printed area is to be
+rotated 90 degrees.  In non-rotated output the X\-axis of the printed
+area runs along the short dimension of the page (``portrait''
+orientation); in rotated output the X\-axis runs along the long
+dimension of the page (``landscape'' orientation).  Defaults to
+\f(CW0\fR.
+.TP
+\fB\-maxpect \fIboolean\fR
+Indicates to scale the plot so that it fills the PostScript page.
+The aspect ratio of the barchart is still retained.  The default is
+\f(CW0\fR.
+.TP
+\fB\-padx \fIpad\fR
+Sets the horizontal padding for the left and right page borders.  The
+borders are exterior to the plot.  \fIPad\fR can be a list of one or
+two screen distances.  If \fIpad\fR has two elements, the left border is padded
+by the first distance and the right border by the second.  If
+\fIpad\fR has just one distance, both the left and right borders are
+padded evenly.  The default is \f(CW1i\fR.
+.TP
+\fB\-pady \fIpad\fR 
+Sets the vertical padding for the top and bottom page borders. The
+borders are exterior to the plot.  \fIPad\fR can be a list of one or
+two screen distances.  If \fIpad\fR has two elements, the top border is padded
+by the first distance and the bottom border by the second.  If
+\fIpad\fR has just one distance, both the top and bottom borders are
+padded evenly.  The default is \f(CW1i\fR.
+.TP
+\fB\-paperheight \fIpixels\fR
+Sets the height of the postscript page.  This can be used to select
+between different page sizes (letter, A4, etc).  The default height is
+\f(CW11.0i\fR.
+.TP
+\fB\-paperwidth \fIpixels\fR
+Sets the width of the postscript page.  This can be used to select
+between different page sizes (letter, A4, etc).  The default width is
+\f(CW8.5i\fR.
+.TP
+\fB\-width \fIpixels\fR
+Sets the width of the plot.  This lets you generate a plot
+of a width different from that of the widget.  If \fIpixels\fR
+is 0, the width is the same as the widget's width.  The default is
+\f(CW0\fR.
+.PP
+Postscript configuration options may be also be set by the
+\fBoption\fR command.  The resource name and class are
+\f(CWpostscript\fR and \f(CWPostscript\fR respectively.
+.CS
+option add *Barchart.postscript.Decorations false
+option add *Barchart.Postscript.Landscape   true
+.CE
+.RE
+.TP
+\fIpathName \fBpostscript output \fR?\fIfileName\fR? ?\fIoption value\fR?...
+Outputs a file of encapsulated PostScript.  If a
+\fIfileName\fR argument isn't present, the command returns the
+PostScript. If any \fIoption-value\fR pairs are present, they set
+configuration options controlling how the PostScript is generated.
+\fIOption\fR and \fIvalue\fR can be anything accepted by the
+postscript \fBconfigure\fR operation above.
+.SS "MARKER COMPONENTS"
+Markers are simple drawing procedures used to annotate or highlight
+areas of the graph.  Markers have various types: text strings,
+bitmaps, images, connected lines, windows, or polygons.  They can be
+associated with a particular element, so that when the element is
+hidden or un-hidden, so is the marker.  By default, markers are the
+last items drawn, so that data elements will appear in
+behind them.  You can change this by configuring the \fB\-under\fR
+option.
+.PP
+Markers, in contrast to elements, don't affect the scaling of the
+coordinate axes.  They can also have \fIelastic\fR coordinates
+(specified by \f(CW-Inf\fR and \f(CWInf\fR respectively) that translate
+into the minimum or maximum limit of the axis.  For example, you can
+place a marker so it always remains in the lower left corner of the
+plotting area, by using the coordinates \f(CW-Inf\fR,\f(CW-Inf\fR.
+.PP
+The following operations are available for markers.
+.TP
+\fIpathName \fBmarker after \fImarkerId\fR ?\fIafterId\fR?
+Changes the order of the markers, drawing the first
+marker after the second.  If no second \fIafterId\fR argument is
+specified, the marker is placed at the end of the display list.  This
+command can be used to control how markers are displayed since markers
+are drawn in the order of this display list.
+.TP
+\fIpathName \fBmarker before \fImarkerId\fR ?\fIbeforeId\fR?
+Changes the order of the markers, drawing the first
+marker before the second.  If no second \fIbeforeId\fR argument is
+specified, the marker is placed at the beginning of the display list.
+This command can be used to control how markers are displayed since
+markers are drawn in the order of this display list.
+.TP
+\fIpathName \fBmarker bind \fItagName\fR ?\fIsequence\fR?  ?\fIcommand\fR? 
+Associates \fIcommand\fR with \fItagName\fR such that whenever the
+event sequence given by \fIsequence\fR occurs for a marker with this
+tag, \fIcommand\fR will be invoked.  The syntax is similar to the 
+\fBbind\fR command except that it operates on graph markers, rather 
+than widgets. See the \fBbind\fR manual entry for
+complete details on \fIsequence\fR and the substitutions performed on 
+\fIcommand\fR before invoking it.  
+.sp
+If all arguments are specified then a new binding is created, replacing 
+any existing binding for the same \fIsequence\fR and \fItagName\fR.
+If the first character of \fIcommand\fR is \f(CW+\fR then \fIcommand\fR 
+augments an existing binding rather than replacing it. 
+If no \fIcommand\fR argument is provided then the command currently
+associated with \fItagName\fR and \fIsequence\fR (it's an error occurs 
+if there's no such binding) is returned.  If both \fIcommand\fR and 
+\fIsequence\fR are missing then a list of all the event sequences for 
+which bindings have been defined for \fItagName\fR. 
+.TP
+\fIpathName \fBmarker cget \fIoption\fR
+Returns the current value of the marker configuration option given by
+\fIoption\fR.  \fIOption\fR may be any option described
+below in the \fBconfigure\fR operation.
+.TP
+\fIpathName \fBmarker configure \fImarkerId\fR ?\fIoption value\fR?...
+Queries or modifies the configuration options for markers.  If
+\fIoption\fR isn't specified, a list describing the current
+options for \fImarkerId\fR is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is returned.
+If one or more \fIoption\fR and \fIvalue\fR pairs are specified, then
+for each pair, the marker option \fIoption\fR is set to \fIvalue\fR.
+.sp
+The following options are valid for all markers.
+Each type of marker also has its own type-specific options.  
+They are described in the sections below.
+.RS
+.TP
+\fB\-bindtags \fItagList\fR
+Specifies the binding tags for the marker.  \fITagList\fR is a list
+of binding tag names.  The tags and their order will determine how
+events for markers are handled.  Each tag in the list matching the 
+current event sequence will have its Tcl command executed.  Implicitly 
+the name of the marker is always the first tag in the list.
+The default value is \f(CWall\fR.
+.TP
+\fB\-coords \fIcoordList\fR
+Specifies the coordinates of the marker.  \fICoordList\fR is 
+a list of graph-coordinates.  The number of coordinates required
+is dependent on the type of marker.  Text, image, and window markers
+need only two coordinates (an X\-Y coordinate).   Bitmap markers
+can take either two or four coordinates (if four, they represent the
+corners of the bitmap). Line markers
+need at least four coordinates, polygons at least six.
+If \fIcoordList\fR is \f(CW""\fR, the marker will not be displayed.
+The default is \f(CW""\fR.
+.TP
+\fB\-element \fIelemName\fR
+Links the marker with the element \fIelemName\fR.  The marker is
+drawn only if the element is also currently displayed (see the
+element's \fBshow\fR operation).  If \fIelemName\fR is \f(CW""\fR, the
+marker is always drawn.  The default is \f(CW""\fR.
+.TP
+\fB\-hide \fIboolean\fR 
+Indicates whether the marker is drawn. If \fIboolean\fR is true,
+the marker is not drawn.  The default is \f(CWno\fR.
+.TP
+\fB\-mapx \fIxAxis\fR 
+Specifies the X\-axis to map the marker's X\-coordinates onto.
+\fIXAxis\fR must the name of an axis.  The default is \f(CWx\fR.
+.TP
+\fB\-mapy \fIyAxis\fR
+Specifies the Y\-axis to map the marker's Y\-coordinates onto.
+\fIYAxis\fR must the name of an axis.  The default is \f(CWy\fR.
+.TP
+\fB\-name \fImarkerId\fR
+Changes the identifier for the marker.  The identifier \fImarkerId\fR 
+can not already be used by another marker.  If this option
+isn't specified, the marker's name is uniquely generated.
+.TP
+\fB\-under \fIboolean\fR
+Indicates whether the marker is drawn below/above data
+elements.  If \fIboolean\fR is true, the marker is be drawn
+underneath the data elements.  Otherwise, the marker is
+drawn on top of the element.  The default is \f(CW0\fR.
+.TP
+\fB\-xoffset \fIpixels\fR
+Specifies a screen distance to offset the marker horizontally. 
+\fIPixels\fR is a valid screen distance, such as \f(CW2\fR or \f(CW1.2i\fR.
+The default is \f(CW0\fR.
+.TP
+\fB\-yoffset \fIpixels\fR
+Specifies a screen distance to offset the markers vertically.
+\fIPixels\fR is a valid screen distance, such as \f(CW2\fR or \f(CW1.2i\fR.
+The default is \f(CW0\fR.
+.PP
+Marker configuration options may also be set by the \fBoption\fR command.
+The resource class is either \f(CWBitmapMarker\fR,  \f(CWImageMarker\fR, 
+\f(CWLineMarker\fR, \f(CWPolygonMarker\fR, \f(CWTextMarker\fR, or \f(CWWindowMarker\fR,
+depending on the type of marker.  The resource name is the name of the
+marker.
+.CS
+option add *Barchart.TextMarker.Foreground white
+option add *Barchart.BitmapMarker.Foreground white
+option add *Barchart.m1.Background     blue
+.CE
+.RE
+.TP
+\fIpathName \fBmarker create \fItype\fR ?\fIoption value\fR?...
+Creates a marker of the selected type. \fIType\fR may be either
+\f(CWtext\fR, \f(CWline\fR, \f(CWbitmap\fR, \f(CWimage\fR, \f(CWpolygon\fR, or
+\f(CWwindow\fR.  This command returns the marker identifier, 
+used as the \fImarkerId\fR argument in the other marker-related
+commands.  If the \fB\-name\fR option is used, this overrides the
+normal marker identifier.  If the name provided is already used for
+another marker, the new marker will replace the old.
+.TP
+\fIpathName \fBmarker delete\fR ?\fIname\fR?...
+Removes one of more markers.  The graph will automatically be redrawn
+without the marker.\fR.  
+.TP
+\fIpathName \fBmarker exists \fImarkerId\fR 
+Returns \f(CW1\fR if the marker \fImarkerId\fR exists and \f(CW0\fR
+otherwise.
+.TP
+\fIpathName \fBmarker names\fR ?\fIpattern\fR?  
+Returns the names of all the markers that currently exist.  If
+\fIpattern\fR is supplied, only those markers whose names match it
+will be returned.
+.TP
+\fIpathName \fBmarker type \fImarkerId\fR 
+Returns the type of the marker given by \fImarkerId\fR, such as
+\f(CWline\fR or \f(CWtext\fR.  If \fImarkerId\fR is not a valid a marker
+identifier, \f(CW""\fR is returned.
+.SS "BITMAP MARKERS"
+A bitmap marker displays a bitmap.  The size of the
+bitmap is controlled by the number of coordinates specified.  If two
+coordinates, they specify the position of the top-left corner of the
+bitmap.  The bitmap retains its normal width and height.  If four
+coordinates, the first and second pairs of coordinates represent the
+corners of the bitmap.  The bitmap will be stretched or reduced as
+necessary to fit into the bounding rectangle.
+.PP
+Bitmap markers are created with the marker's \fBcreate\fR operation in
+the form:
+.DS
+\fIpathName \fBmarker create bitmap \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR pairs, each 
+sets a configuration options for the marker.  These
+same \fIoption\fR\-\fIvalue\fR pairs may be used with the marker's
+\fBconfigure\fR operation.
+.PP
+The following options are specific to bitmap markers:
+.TP
+\fB\-background \fIcolor\fR
+Same as the \fB\-fill\fR option.
+.TP
+\fB\-bitmap \fIbitmap\fR
+Specifies the bitmap to be displayed.  If \fIbitmap\fR is \f(CW""\fR,
+the marker will not be displayed.  The default is \f(CW""\fR.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the background color of the bitmap.  If \fIcolor\fR is the empty
+string, no background will be transparent.  The default background color is
+\f(CW""\fR.
+.TP
+\fB\-foreground \fIcolor\fR 
+Same as the \fB\-outline\fR option.
+.TP
+\fB\-mask \fImask\fR
+Specifies a mask for the bitmap to be displayed. This mask is a bitmap
+itself, denoting the pixels that are transparent.  If \fImask\fR is
+\f(CW""\fR, all pixels of the bitmap will be drawn.  The default is
+\f(CW""\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the foreground color of the bitmap. The default value is \f(CWblack\fR.
+.TP
+\fB\-rotate \fItheta\fR
+Sets the rotation of the bitmap.  \fITheta\fR is a real number
+representing the angle of rotation in degrees.  The marker is first
+rotated and then placed according to its anchor position.  The default
+rotation is \f(CW0.0\fR.
+.SS "IMAGE MARKERS"
+A image marker displays an image.  Image markers are
+created with the marker's \fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create image \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR\-\fIvalue\fR pairs may be
+used with the marker's \fBconfigure\fR operation.
+.PP
+The following options are specific to image markers:
+.TP
+\fB\-anchor \fIanchor\fR
+\fIAnchor\fR tells how to position the image relative to the
+positioning point for the image. For example, if \fIanchor\fR
+is \f(CWcenter\fR then the image is centered on the point;  if
+\fIanchor\fR is \f(CWn\fR then the image will be drawn such that
+the top center point of the rectangular region occupied by the
+image will be at the positioning point.
+This option defaults to \f(CWcenter\fR.
+.TP
+\fB\-image \fIimage\fR
+Specifies the image to be drawn.
+If \fIimage\fR is \f(CW""\fR, the marker will not be
+drawn.  The default is \f(CW""\fR.
+.SS "LINE MARKERS"
+A line marker displays one or more connected line segments.
+Line markers are created with marker's \fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create line \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR-\fIvalue\fR pairs may be
+used with the marker's \fBconfigure\fR operation.
+.PP
+The following options are specific to line markers:
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the line. \fIDashList\fR is a list of up to 11
+numbers that alternately represent the lengths of the dashes and gaps
+on the line.  Each number must be between 1 and 255.  If
+\fIdashList\fR is \f(CW""\fR, the marker line will be solid.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the background color of the line.  This color is used with
+striped lines (see the \fB\-fdashes\R option). If \fIcolor\fR is
+the empty string, no background color is drawn (the line will be
+dashed, not striped).  The default background color is \f(CW""\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of the lines.
+The default width is \f(CW0\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the foreground color of the line. The default value is \f(CWblack\fR.
+.TP
+\fB\-stipple \fIbitmap\fR
+Specifies a stipple pattern used to draw the line, rather than
+a solid line.
+\fIBitmap\fR specifies a bitmap to use as the stipple
+pattern.  If \fIbitmap\fR is \f(CW""\fR, then the
+line is drawn in a solid fashion. The default is \f(CW""\fR.
+.SS "POLYGON MARKERS"
+A polygon marker displays a closed region described as two or more
+connected line segments.  It is assumed the first and
+last points are connected.  Polygon markers are created using the
+marker \fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create polygon \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR\-\fIvalue\fR pairs may be
+used with the \fBmarker configure\fR command to change the marker's
+configuration.
+The following options are supported for polygon markers:
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the outline of the polygon. \fIDashList\fR is a
+list of up to 11 numbers that alternately represent the lengths of
+the dashes and gaps on the outline.  Each number must be between 1 and
+255. If \fIdashList\fR is \f(CW""\fR, the outline will be a solid line.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the fill color of the polygon.  If \fIcolor\fR is \f(CW""\fR, then
+the interior of the polygon is transparent.
+The default is \f(CWwhite\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of the outline of the polygon. If \fIpixels\fR is zero, 
+no outline is drawn. The default is \f(CW0\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the color of the outline of the polygon.  If the polygon is
+stippled (see the \fB\-stipple\fR option), then this represents the
+foreground color of the stipple.  The default is \f(CWblack\fR.
+.TP
+\fB\-stipple \fIbitmap\fR
+Specifies that the polygon should be drawn with a stippled pattern
+rather than a solid color. \fIBitmap\fR specifies a bitmap to use as
+the stipple pattern.  If \fIbitmap\fR is \f(CW""\fR, then the polygon is
+filled with a solid color (if the \fB\-fill\fR option is set).  The
+default is \f(CW""\fR.
+.SS "TEXT MARKERS"
+A text marker displays a string of characters on one or more lines of
+text.  Embedded newlines cause line breaks.  They may be used to
+annotate regions of the graph.  Text markers are created with the
+\fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create text \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR pairs, 
+each sets a configuration option for the text marker.  
+These same \fIoption\fR\-\fIvalue\fR pairs may be used with the 
+marker's \fBconfigure\fR operation.  
+.PP
+The following options are specific to text markers:
+.TP
+\fB\-anchor \fIanchor\fR
+\fIAnchor\fR tells how to position the text relative to the
+positioning point for the text. For example, if \fIanchor\fR is
+\f(CWcenter\fR then the text is centered on the point; if
+\fIanchor\fR is \f(CWn\fR then the text will be drawn such that the
+top center point of the rectangular region occupied by the text will
+be at the positioning point.  This default is \f(CWcenter\fR.
+.TP
+\fB\-background \fIcolor\fR
+Same as the \fB\-fill\fR option.
+.TP
+\fB\-font \fIfontName\fR
+Specifies the font of the text.  The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-120-*\fR.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the background color of the text.  If \fIcolor\fR is the empty
+string, no background will be transparent.  The default background color is
+\f(CW""\fR.
+.TP
+\fB\-foreground \fIcolor\fR
+Same as the \fB\-outline\fR option.
+.TP
+\fB\-justify \fIjustify\fR
+Specifies how the text should be justified.  This matters only when
+the marker contains more than one line of text. \fIJustify\fR must be
+\f(CWleft\fR, \f(CWright\fR, or \f(CWcenter\fR.  The default is
+\f(CWcenter\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the color of the text. The default value is \f(CWblack\fR.
+.TP
+\fB\-padx \fIpad\fR
+Sets the padding to the left and right exteriors of the text.
+\fIPad\fR can be a list of one or two screen distances.  If \fIpad\fR
+has two elements, the left side of the text is padded by the first
+distance and the right side by the second.  If \fIpad\fR has just one
+distance, both the left and right sides are padded evenly.  The
+default is \f(CW4\fR.
+.TP
+\fB\-pady \fIpad\fR
+Sets the padding above and below the text.  \fIPad\fR can be a list of
+one or two screen distances.  If \fIpad\fR has two elements, the area above the
+text is padded by the first distance and the area below by the second.
+If \fIpad\fR is just one distance, both the top and bottom areas
+are padded evenly.  The default is \f(CW4\fR.
+.TP
+\fB\-rotate \fItheta\fR
+Specifies the number of degrees to rotate the text.  \fITheta\fR is a
+real number representing the angle of rotation.  The marker is first
+rotated along its center and is then drawn according to its anchor
+position. The default is \f(CW0.0\fR.
+.TP
+\fB\-text \fItext\fR
+Specifies the text of the marker.  The exact way the text is
+displayed may be affected by other options such as \fB\-anchor\fR or
+\fB\-rotate\fR.
+.SS "WINDOW MARKERS"
+A window marker displays a widget at a given position.
+Window markers are created with the marker's \fBcreate\fR operation in
+the form:
+.DS
+\fIpathName \fBmarker create window \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR\-\fIvalue\fR pairs may be
+used with the marker's \fBconfigure\fR command.
+.PP
+The following options are specific to window markers:
+.TP
+\fB\-anchor \fIanchor\fR
+\fIAnchor\fR tells how to position the widget relative to the
+positioning point for the widget. For example, if \fIanchor\fR is
+\f(CWcenter\fR then the widget is centered on the point; if \fIanchor\fR
+is \f(CWn\fR then the widget will be displayed such that the top center
+point of the rectangular region occupied by the widget will be at the
+positioning point.  This option defaults to \f(CWcenter\fR.
+.TP
+\fB\-height \fIpixels\fR
+Specifies the height to assign to the marker's window.  If this option
+isn't specified, or if it is specified as \f(CW""\fR, then the window is
+given whatever height the widget requests internally.
+.TP
+\fB\-width \fIpixels\fR
+Specifies the width to assign to the marker's window.  If this option
+isn't specified, or if it is specified as \f(CW""\fR, then the window is
+given whatever width the widget requests internally.
+.TP
+\fB\-window \fIpathName\fR
+Specifies the widget to be managed by the barchart.  \fIPathName\fR must
+be a child of the \fBbarchart\fR widget.
+.SH "GRAPH COMPONENT BINDINGS"
+Specific barchart components, such as elements, markers and legend
+entries, can have a command trigger when event occurs in them, much
+like canvas items in Tk's canvas widget.  Not all event sequences are
+valid.  The only binding events that may be specified are those
+related to the mouse and keyboard (such as \fBEnter\fR, \fBLeave\fR,
+\fBButtonPress\fR, \fBMotion\fR, and \fBKeyPress\fR).
+.PP
+Only one element or marker can be picked during an event.  This means,
+that if the mouse is directly over both an element and a marker, only
+the uppermost component is selected.  This isn't true for legend entries.  
+Both a legend entry and an element (or marker) binding commands 
+will be invoked if both items are picked.
+.PP
+It is possible for multiple bindings to match a particular event.
+This could occur, for example, if one binding is associated with the
+element name and another is associated with one of the element's tags
+(see the \fB\-bindtags\fR option).  When this occurs, all of the 
+matching bindings are invoked.  A binding associated with the element
+name is invoked first, followed by one binding for each of the element's 
+bindtags.  If there are multiple matching bindings for a single tag, 
+then only the most specific binding is invoked.  A continue command 
+in a binding script terminates that script, and a break command 
+terminates that script and skips any remaining scripts for the event, 
+just as for the bind command.
+.PP
+The \fB\-bindtags\fR option for these components controls addition
+tag names which can be matched.  Implicitly elements and markers
+always have tags matching their names.  Setting the value of
+the \fB\-bindtags\fR option doesn't change this.
+.SH "C LANGUAGE API"
+You can manipulate data elements from the C language.  There
+may be situations where it is too expensive to translate the data
+values from ASCII strings.  Or you might want to read data in a
+special file format.
+.PP
+Data can manipulated from the C language using BLT vectors.
+You specify the X-Y data coordinates of an element as vectors and
+manipulate the vector from C.  The barchart will be redrawn automatically
+after the vectors are updated.
+.PP
+From Tcl, create the vectors and configure the element to use them.
+.CS
+vector X Y
+\&.g element configure line1 -xdata X -ydata Y
+.CE
+To set data points from C, you pass the values as arrays of doubles
+using the \fBBlt_ResetVector\fR call.  The vector is reset with the
+new data and at the next idle point (when Tk re-enters its event
+loop), the graph will be redrawn automatically.
+.CS
+#include <tcl.h>
+#include <blt.h>
+
+register int i;
+Blt_Vector *xVec, *yVec;
+double x[50], y[50];
+
+/* Get the BLT vectors "X" and "Y" (created above from Tcl) */
+if ((Blt_GetVector(interp, "X", 50, &xVec) != TCL_OK) ||
+    (Blt_GetVector(interp, "Y", 50, &yVec) != TCL_OK)) {
+    return TCL_ERROR;
+}
+
+for (i = 0; i < 50; i++) {
+    x[i] = i * 0.02;
+    y[i] = sin(x[i]);
+}	
+
+/* Put the data into BLT vectors */
+if ((Blt_ResetVector(xVec, x, 50, 50, TCL_VOLATILE) != TCL_OK) ||
+    (Blt_ResetVector(yVec, y, 50, 50, TCL_VOLATILE) != TCL_OK)) {
+   return TCL_ERROR;
+}
+.CE
+See the \fBvector\fR manual page for more details.
+.SH SPEED TIPS
+There may be cases where the bar chart needs to be drawn and updated as
+quickly as possible.  If drawing speed becomes a big
+problem, here are a few tips to speed up displays.
+.TP 2
+\(bu 
+Try to minimize the number of data points.  The more data points 
+looked at, the more work the bar chart must do.  
+.TP 2
+\(bu 
+If your data is generated as floating point values, the time required
+to convert the data values to and from ASCII strings can be
+significant, especially when there any many data points.  You can
+avoid the redundant string-to-decimal conversions using the C API to
+BLT vectors.
+.TP 2
+\(bu
+Don't stipple or dash the element.  Solid bars are much faster.
+.TP 2
+\(bu 
+If you update data elements frequently, try turning off the
+widget's \fB\-bufferelements\fR option.  When the bar chart is first
+displayed, it draws data elements into an internal pixmap.  The pixmap
+acts as a cache, so that when the bar chart needs to be redrawn again, and
+the data elements or coordinate axes haven't changed, the pixmap is
+simply copied to the screen.  This is especially useful when you are
+using markers to highlight points and regions on the bar chart.  But if
+the bar chart is updated frequently, changing either the element data or
+coordinate axes, the buffering becomes redundant.
+.SH LIMITATIONS
+Auto-scale routines do not use requested min/max limits
+as boundaries when the axis is logarithmically scaled.  
+.PP
+The PostScript output generated for polygons with more than 1500
+points may exceed the limits of some printers (See PostScript Language
+Reference Manual, page 568).  The work-around is to break the polygon
+into separate pieces.
+.SH KEYWORDS
+bar chart, widget
diff --git a/doc/graph.n b/doc/graph.n
new file mode 100644
index 0000000..c631975
--- /dev/null
+++ b/doc/graph.n
@@ -0,0 +1,2397 @@
+'\"
+'\" Copyright 1991-1998 by Bell Labs Innovations for Lucent Technologies.
+'\"
+'\" Permission to use, copy, modify, and distribute this software and its
+'\" documentation for any purpose and without fee is hereby granted, provided
+'\" that the above copyright notice appear in all copies and that both that the
+'\" copyright notice and warranty disclaimer appear in supporting documentation,
+'\" and that the names of Lucent Technologies any of their entities not be used
+'\" in advertising or publicity pertaining to distribution of the software
+'\" without specific, written prior permission.
+'\"
+'\" Lucent Technologies disclaims all warranties with regard to this software,
+'\" including all implied warranties of merchantability and fitness.  In no event
+'\" shall Lucent Technologies be liable for any special, indirect or
+'\" consequential damages or any damages whatsoever resulting from loss of use,
+'\" data or profits, whether in an action of contract, negligence or other
+'\" tortuous action, arising out of or in connection with the use or performance
+'\" of this software.  
+'\"
+'\" Graph widget created by Sani Nassif and George Howlett.
+'\"
+.so man.macros
+.TH graph n BLT_VERSION BLT "BLT Built-In Commands"
+.BS
+'\" Note:  do not modify the .SH NAME line immediately below!
+.SH NAME
+graph \-  2D graph for plotting X\-Y coordinate data.
+.SH SYNOPSIS
+\fBgraph\fI \fIpathName \fR?\fIoption value\fR?...
+.BE
+.SH DESCRIPTION
+The \fBgraph\fR command creates a graph for plotting
+two-dimensional data (X\-Y coordinates). It has many configurable
+components: coordinate axes, elements, legend, grid lines, cross
+hairs, etc.  They allow you to customize the look and feel of the
+graph.
+.SH INTRODUCTION
+The \fBgraph\fR command creates a new window for plotting
+two-dimensional data (X\-Y coordinates).  Data points are plotted in a
+rectangular area displayed in the center of the new window.  This is the
+\fIplotting area\fR.  The coordinate axes are drawn in the
+margins around the plotting area.  By default, the legend is displayed
+in the right margin.  The title is displayed in top margin.
+.PP
+The \fBgraph\fR widget is composed of several components: coordinate
+axes, data elements, legend, grid, cross hairs, pens, postscript, and
+annotation markers.
+.TP 1i
+\f(CWaxis\fR 
+The graph has four standard axes (\f(CWx\fR, \f(CWx2\fR,
+\f(CWy\fR, and \f(CWy2\fR), but you can create and display any number 
+of axes.  Axes control what region of data is
+displayed and how the data is scaled. Each axis consists of the axis
+line, title, major and minor ticks, and tick labels.  Tick labels
+display the value at each major tick.
+.TP 1i
+\f(CWcrosshairs\fR 
+Cross hairs are used to position the mouse pointer relative to the X
+and Y coordinate axes. Two perpendicular lines, intersecting at the
+current location of the mouse, extend across the plotting area to the
+coordinate axes.
+.TP 1i
+\f(CWelement\fR 
+An element represents a set of data points. Elements can be plotted 
+with a symbol at each data point and lines connecting the points. 
+The appearance of the element, such as its symbol, line width, and 
+color is configurable.
+.TP 1i
+\f(CWgrid\fR
+Extends the major and minor ticks of the X\-axis and/or Y\-axis across the 
+plotting area. 
+.TP 1i
+\f(CWlegend\fR 
+The legend displays the name and symbol of each data element. 
+The legend can be drawn in any margin or in the plotting area.
+.TP 1i
+\f(CWmarker\fR
+Markers are used annotate or highlight areas of the graph. For 
+example, you could use a polygon marker to fill an area under a 
+curve, or a text marker to label a particular data point. Markers 
+come in various forms: text strings, bitmaps, connected line 
+segments, images, polygons, or embedded widgets.
+.TP 1i
+\f(CWpen\fR 
+Pens define attributes (both symbol and line style) for elements. 
+Data elements use pens to specify how they should be drawn.  A data 
+element may use many pens at once.  Here, the particular pen 
+used for a data point is determined from each element's weight 
+vector (see the element's \fB\-weight\fR and \fB\-style\fR options).  
+.TP 1i
+\f(CWpostscript\fR
+The widget can generate encapsulated PostScript output. This component
+has several options to configure how the PostScript is generated.
+.SH SYNTAX
+.DS
+\fBgraph \fIpathName \fR?\fIoption value\fR?...
+.DE
+The \fBgraph\fR command creates a new window \fIpathName\fR and makes
+it into a \fBgraph\fR widget.  At the time this command is invoked, there
+must not exist a window named \fIpathName\fR, but \fIpathName\fR's
+parent must exist.  Additional options may be specified on the
+command line or in the option database to configure aspects of the
+graph such as its colors and font.  See the \fBconfigure\fR operation
+below for the exact details about what \fIoption\fR and \fIvalue\fR
+pairs are valid.
+.PP
+If successful, \fBgraph\fR returns the path name of the widget.  It
+also creates a new Tcl command by the same name.  You can use this
+command to invoke various operations that query or modify the graph.
+The general form is:
+.DS
+\fIpathName \fIoperation\fR \fR?\fIarg\fR?...
+.DE
+Both \fIoperation\fR and its arguments determine the exact behavior of
+the command.  The operations available for the graph are described in 
+the 
+.SB "GRAPH OPERATIONS"
+section.
+.PP
+The command can also be used to access components of the graph.
+.DS
+\fIpathName component operation\fR ?\fIarg\fR?...
+.DE
+The operation, now located after the name of the component, is the
+function to be performed on that component. Each component has its own
+set of operations that manipulate that component.  They will be
+described below in their own sections.
+.SH EXAMPLE
+The \fBgraph\fR command creates a new graph.  
+.CS
+# Create a new graph.  Plotting area is black.
+graph .g \-plotbackground black
+.CE
+A new Tcl command \f(CW.g\fR is also created.  This command can be used
+to query and modify the graph.  For example, to change the title of
+the graph to "My Plot", you use the new command and the graph's
+\fBconfigure\fR operation.
+.CS
+# Change the title.
+\&.g configure \-title "My Plot"
+.CE
+A graph has several components. To access a particular component you
+use the component's name. For example, to add data elements, you use
+the new command and the \fBelement\fR component.
+.CS
+# Create a new element named "line1"
+\&.g element create line1 \\
+	\-xdata { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 } \\
+	\-ydata { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 
+		155.85 166.60 175.38 }
+.CE
+The element's X-Y coordinates are specified using lists of
+numbers.  Alternately, BLT vectors could be used to hold the X\-Y
+coordinates.
+.CS
+# Create two vectors and add them to the graph.
+vector xVec yVec
+xVec set { 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 }
+yVec set { 26.18 50.46 72.85 93.31 111.86 128.47 143.14 155.85 
+	166.60 175.38 }
+\&.g element create line1 \-xdata xVec \-ydata yVec
+.CE
+The advantage of using vectors is that when you modify one, the graph
+is automatically redrawn to reflect the new values.
+.CS
+# Change the y coordinate of the first point.
+set yVector(0) 25.18
+.CE
+An element named \f(CWe1\fR is now created in \f(CW.b\fR.  It 
+is automatically added to the display list of elements.  You can
+use this list to control in what order elements are displayed.
+To query or reset the element display list, you use the element's 
+\fBshow\fR operation.
+.CS
+# Get the current display list 
+set elemList [.b element show]
+# Remove the first element so it won't be displayed.
+\&.b element show [lrange $elemList 0 end]
+.CE
+The element will be displayed by as many bars as there are data points
+(in this case there are ten).  The bars will be drawn centered at the
+x-coordinate of the data point.  All the bars will have the same
+attributes (colors, stipple, etc).  The width of each bar is by
+default one unit.  You can change this with using the \fB\-barwidth\fR
+option.
+.CS
+# Change the X\-Y coordinates of the first point.
+set xVec(0) 0.18
+set yVec(0) 25.18
+.CE
+An element named \f(CWline1\fR is now created in \f(CW.g\fR.  By
+default, the element's label in the legend will be also \f(CWline1\fR.
+You can change the label, or specify no legend entry, again using the
+element's \fBconfigure\fR operation.
+.CS
+# Don't display "line1" in the legend.
+\&.g element configure line1 \-label ""
+.CE
+You can configure more than just the element's label.  An element has
+many attributes such as symbol type and size, dashed or solid lines,
+colors, line width, etc.
+.CS
+\&.g element configure line1 \-symbol square \-color red \\
+	\-dashes { 2 4 2 } \-linewidth 2 \-pixels 2c
+.CE
+Four coordinate axes are automatically created: \f(CWx\fR, \f(CWx2\fR,
+\f(CWy\fR, and \f(CWy2\fR.  And by default, elements are mapped onto the
+axes \f(CWx\fR and \f(CWy\fR.  This can be changed with the \fB\-mapx\fR
+and \fB\-mapy\fR options.
+.CS
+# Map "line1" on the alternate Y\-axis "y2".
+\&.g element configure line1 \-mapy y2
+.CE
+Axes can be configured in many ways too.  For example, you change the
+scale of the Y\-axis from linear to log using the \fBaxis\fR component.
+.CS
+# Y\-axis is log scale.
+\&.g axis configure y \-logscale yes
+.CE
+One important way axes are used is to zoom in on a particular data
+region.  Zooming is done by simply specifying new axis limits using
+the \fB\-min\fR and \fB\-max\fR configuration options.
+.CS
+\&.g axis configure x \-min 1.0 \-max 1.5
+\&.g axis configure y \-min 12.0 \-max 55.15
+.CE
+To zoom interactively, you link the \fBaxis configure\fR operations with
+some user interaction (such as pressing the mouse button), using the
+\fBbind\fR command.  To convert between screen and graph coordinates,
+use the \fBinvtransform\fR operation.
+.CS
+# Click the button to set a new minimum 
+bind .g <ButtonPress-1> { 
+    %W axis configure x \-min [%W axis invtransform x %x]
+    %W axis configure x \-min [%W axis invtransform x %y]
+}
+.CE
+By default, the limits of the axis are determined from data values.
+To reset back to the default limits, set the \fB\-min\fR and
+\fB\-max\fR options to the empty value.
+.CS
+# Reset the axes to autoscale again.
+\&.g axis configure x \-min {} \-max {}
+\&.g axis configure y \-min {} \-max {}
+.CE
+By default, the legend is drawn in the right margin.  You can
+change this or any legend configuration options using the
+\fBlegend\fR component.
+.CS
+# Configure the legend font, color, and relief
+\&.g legend configure \-position left \-relief raised \\
+	\-font fixed \-fg blue
+.CE
+To prevent the legend from being displayed, turn on the \fB\-hide\fR
+option.
+.CS
+# Don't display the legend.
+\&.g legend configure \-hide yes\fR
+.CE
+The \fBgraph\fR widget has simple drawing procedures called markers.
+They can be used to highlight or annotate data in the graph. The types
+of markers available are bitmaps, images, polygons, lines, or windows.
+Markers can be used, for example, to mark or brush points.  In this
+example, is a text marker that labels the data first point.  Markers
+are created using the \fBmarker\fR component.
+.CS
+# Create a label for the first data point of "line1".
+\&.g marker create text \-name first_marker \-coords { 0.2 26.18 } \\
+	\-text "start" \-anchor se \-xoffset -10 \-yoffset -10
+.CE
+This creates a text marker named \f(CWfirst_marker\fR.  It will display
+the text "start" near the coordinates of the first data point.  The
+\fB\-anchor\fR, \fB\-xoffset\fR, and \fB\-yoffset\fR options are used
+to display the marker above and to the left of the data point, so that
+the data point isn't covered by the marker.  By default,
+markers are drawn last, on top of data.  You can change this with the
+\fB\-under\fR option.
+.CS
+# Draw the label before elements are drawn.
+\&.g marker configure first_marker \-under yes
+.CE
+You can add cross hairs or grid lines using the \fBcrosshairs\fR and
+\fBgrid\fR components.
+.CS
+# Display both cross hairs and grid lines.
+\&.g crosshairs configure \-hide no \-color red
+\&.g grid configure \-hide no \-dashes { 2 2 }
+# Set up a binding to reposition the crosshairs.
+bind .g <Motion> {
+    .g crosshairs configure -position @%x,%y
+}
+.CE
+The crosshairs are repositioned as the mouse pointer is moved
+in the graph.  The pointer X-Y coordinates define the center
+of the crosshairs.
+.PP
+Finally, to get hardcopy of the graph, use the \fBpostscript\fR
+component.
+.CS
+# Print the graph into file "file.ps"
+\&.g postscript output file.ps \-maxpect yes \-decorations no
+.CE
+This generates a file \f(CWfile.ps\fR containing the encapsulated
+PostScript of the graph.  The option \fB\-maxpect\fR says to scale the
+plot to the size of the page.  Turning off the \fB\-decorations\fR
+option denotes that no borders or color backgrounds should be
+drawn (i.e. the background of the margins, legend, and plotting
+area will be white).
+.SH "GRAPH OPERATIONS"
+.TP
+\fIpathName \fBaxis \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "AXIS COMPONENTS"
+section.
+.TP
+\fIpathName \fBbar \fIelemName \fR?\fIoption value\fR?...
+Creates a new barchart element \fIelemName\fR.  It's an
+error if an element \fIelemName\fR already exists.  
+See the manual for \fBbarchart\fR for details about
+what \fIoption\fR and \fIvalue\fR pairs are valid.
+.TP
+\fIpathName \fBcget\fR \fIoption\fR
+Returns the current value of the configuration option given by
+\fIoption\fR.  \fIOption\fR may be any option described
+below for the \fBconfigure\fR operation.
+.TP
+\fIpathName \fBconfigure \fR?\fIoption value\fR?...
+Queries or modifies the configuration options of the graph.  If
+\fIoption\fR isn't specified, a list describing the current
+options for \fIpathName\fR is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is returned.
+If one or more \fIoption\fR and \fIvalue\fR pairs are specified, then
+for each pair, the option \fIoption\fR is set to \fIvalue\fR.
+The following options are valid.
+.RS
+.TP
+\fB\-aspect \fIwidth/height\fR
+Force a fixed aspect ratio of \fIwidth/height\fR, a floating point number.
+.TP
+\fB\-background \fIcolor\fR
+Sets the background color. This includes the margins and
+legend, but not the plotting area.
+.TP
+\fB\-borderwidth \fIpixels\fR
+Sets the width of the 3\-D border around the outside edge of the widget.  The
+\fB\-relief\fR option determines if the border is to be drawn.  The
+default is \f(CW2\fR.
+.TP
+\fB\-bottommargin \fIpixels\fR
+If non-zero, overrides the computed size of the margin extending 
+below the X\-coordinate axis.
+If \fIpixels\fR is \f(CW0\fR, the automatically computed size is used.  
+The default is \f(CW0\fR.
+.TP
+\fB\-bufferelements \fIboolean\fR
+Indicates whether an internal pixmap to buffer the display of data
+elements should be used.  If \fIboolean\fR is true, data elements are
+drawn to an internal pixmap.  This option is especially useful when
+the graph is redrawn frequently while the remains data unchanged (for
+example, moving a marker across the plot).  See the
+.SB "SPEED TIPS"
+section.
+The default is \f(CW1\fR.
+.TP
+\fB\-cursor \fIcursor\fR
+Specifies the widget's cursor.  The default cursor is \f(CWcrosshair\fR.
+.TP
+\fB\-font \fIfontName\fR 
+Specifies the font of the graph title. The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-18-180-*\fR.
+.TP
+\fB\-halo \fIpixels\fR 
+Specifies a maximum distance to consider when searching for the
+closest data point (see the element's \fBclosest\fR operation below).
+Data points further than \fIpixels\fR away are ignored.  The default is
+\f(CW0.5i\fR.
+.TP
+\fB\-height \fIpixels\fR
+Specifies the requested height of widget.  The default is
+\f(CW4i\fR.
+.TP
+\fB\-invertxy \fIboolean\fR
+Indicates whether the placement X\-axis and Y\-axis should be inverted.  If
+\fIboolean\fR is true, the X and Y axes are swapped.  The default is
+\f(CW0\fR.
+.TP
+\fB\-justify \fIjustify\fR
+Specifies how the title should be justified.  This matters only when
+the title contains more than one line of text. \fIJustify\fR must be
+\f(CWleft\fR, \f(CWright\fR, or \f(CWcenter\fR.  The default is
+\f(CWcenter\fR.
+.TP
+\fB\-leftmargin \fIpixels\fR
+If non-zero, overrides the computed size of the margin extending 
+from the left edge of the window to the Y\-coordinate axis.  
+If \fIpixels\fR is \f(CW0\fR, the automatically computed size is used.  
+The default is \f(CW0\fR.
+.TP
+\fB\-plotbackground \fIcolor\fR
+Specifies the background color of the plotting area.  The default is
+\f(CWwhite\fR.
+.TP
+\fB\-plotborderwidth \fIpixels\fR
+Sets the width of the 3-D border around the plotting area.  The
+\fB\-plotrelief\fR option determines if a border is drawn.  The
+default is \f(CW2\fR.
+.TP
+\fB\-plotpadx \fIpad\fR
+Sets the amount of padding to be added to the left and right sides of
+the plotting area.  \fIPad\fR can be a list of one or two screen
+distances.  If \fIpad\fR has two elements, the left side of the
+plotting area entry is padded by the first distance and the right side
+by the second.  If \fIpad\fR is just one distance, both the left and
+right sides are padded evenly.  The default is \f(CW8\fR.
+.TP
+\fB\-plotpady \fIpad\fR
+Sets the amount of padding to be added to the top and bottom of the
+plotting area.  \fIPad\fR can be a list of one or two screen
+distances.  If \fIpad\fR has two elements, the top of the plotting
+area is padded by the first distance and the bottom by the second.  If
+\fIpad\fR is just one distance, both the top and bottom are padded
+evenly.  The default is \f(CW8\fR.
+.TP
+\fB\-plotrelief \fIrelief\fR
+Specifies the 3-D effect for the plotting area.  \fIRelief\fR
+specifies how the interior of the plotting area should appear relative
+to rest of the graph; for example, \f(CWraised\fR means the plot should
+appear to protrude from the graph, relative to the surface of the
+graph.  The default is \f(CWsunken\fR.
+.TP
+\fB\-relief \fIrelief\fR
+Specifies the 3-D effect for the graph widget.  \fIRelief\fR
+specifies how the graph should appear relative to widget it is packed
+into; for example, \f(CWraised\fR means the graph should
+appear to protrude.  The default is \f(CWflat\fR.
+.TP
+\fB\-rightmargin \fIpixels\fR
+If non-zero, overrides the computed size of the margin extending 
+from the plotting area to the right edge of
+the window. By default, the legend is drawn in this margin. 
+If \fIpixels\fR is \f(CW0\fR, the automatically computed size is used.  
+The default is \f(CW0\fR.
+.TP
+\fB\-takefocus\fR \fIfocus\fR 
+Provides information used when moving the focus from window to window
+via keyboard traversal (e.g., Tab and Shift-Tab).  If \fIfocus\fR is
+\f(CW0\fR, this means that this window should be skipped entirely during
+keyboard traversal.  \f(CW1\fR means that the this window should always
+receive the input focus.  An empty value means that the traversal
+scripts make the decision whether to focus on the window.
+The default is \f(CW""\fR.
+.TP
+\fB\-tile \fIimage\fR 
+Specifies a tiled background for the widget.  If \fIimage\fR isn't
+\f(CW""\fR, the background is tiled using \fIimage\fR.
+Otherwise, the normal background color is drawn (see the
+\fB\-background\fR option).  \fIImage\fR must be an image created
+using the Tk \fBimage\fR command.  The default is \f(CW""\fR.
+.TP
+\fB\-title \fItext\fR 
+Sets the title to \fItext\fR. If \fItext\fR is \f(CW""\fR,
+no title will be displayed.
+.TP
+\fB\-topmargin \fIpixels\fR 
+If non-zero, overrides the computed size of the margin above the x2
+axis.  If \fIpixels\fR is \f(CW0\fR, the automatically computed size
+is used.  The default is \f(CW0\fR.
+.TP
+\fB\-width \fIpixels\fR
+Specifies the requested width of the widget.  The default is
+\f(CW5i\fR.
+.RE
+.TP
+\fIpathName \fBcrosshairs \fIoperation \fR?\fIarg\fR?
+See the 
+.SB "CROSSHAIRS COMPONENT"
+section.
+.TP
+\fIpathName \fBelement \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "ELEMENT COMPONENTS"
+section.
+.TP
+\fIpathName \fBextents \fIitem\fR 
+Returns the size of a particular item in the graph.  \fIItem\fR must
+be either \f(CWleftmargin\fR, \f(CWrightmargin\fR, \f(CWtopmargin\fR,
+\f(CWbottommargin\fR, \f(CWplotwidth\fR, or \f(CWplotheight\fR.
+.TP
+\fIpathName \fBgrid \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "GRID COMPONENT"
+section.
+.TP
+\fIpathName \fBinvtransform \fIwinX winY\fR 
+Performs an inverse coordinate transformation, mapping window
+coordinates back to graph coordinates, using the standard X\-axis and Y\-axis.
+Returns a list of containing the X-Y graph coordinates.
+.TP
+\fIpathName \fBinside \fIx y\fR
+Returns \f(CW1\fR is the designated screen coordinate (\fIx\fR and \fIy\fR)
+is inside the plotting area and \f(CW0\fR otherwise.
+.TP
+\fIpathName \fBlegend \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "LEGEND COMPONENT"
+section.
+.TP
+\fIpathName \fBline\fB operation arg\fR...
+The operation is the same as \fBelement\fR.
+.TP
+\fIpathName \fBmarker \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "MARKER COMPONENTS"
+section.
+.TP
+\fIpathName \fBpostscript \fIoperation \fR?\fIarg\fR?...
+See the 
+.SB "POSTSCRIPT COMPONENT"
+section.
+.TP
+\fIpathName \fBsnap \fR?\fIswitches\fR? \fIoutputName\fR
+Takes a snapshot of the graph, saving the output in \fIoutputName\fR.
+The following switches are available.
+.RS
+.TP 1i
+\fB\-format\fR \fIformat\fR
+Specifies how the snapshot is output. \fIFormat\fR may be one of 
+the following listed below.  The default is \f(CWphoto\fR. 
+.RS
+.TP 
+\f(CWphoto\fR
+Saves a Tk photo image. \fIOutputName\fR represents the name of a 
+Tk photo image that must already have been created.  
+.TP 
+\f(CWwmf\fR
+Saves an Aldus Placeable Metafile.  \fIOutputName\fR represents the
+filename where the metafile is written.  If \fIoutputName\fR is
+\f(CWCLIPBOARD\fR, then output is written directly to the Windows
+clipboard.  This format is available only under Microsoft Windows.
+.TP 
+\f(CWemf\fR
+Saves an Enhanced Metafile. \fIOutputName\fR represents the filename
+where the metafile is written.  If \fIoutputName\fR is
+\f(CWCLIPBOARD\fR, then output is written directly to the Windows
+clipboard.  This format is available only under Microsoft Windows.
+.RE
+.TP 1i
+\fB\-height\fR \fIsize\fR
+Specifies the height of the graph.  \fISize\fR is a screen distance.
+The graph will be redrawn using this dimension, rather than its
+current window height.
+.TP 1i
+\fB\-width\fR \fIsize\fR
+Specifies the width of the graph.  \fISize\fR is a screen distance.
+The graph will be redrawn using this dimension, rather than its
+current window width.
+.RE
+.TP
+\fIpathName \fBtransform \fIx y\fR 
+Performs a coordinate transformation, mapping graph coordinates to
+window coordinates, using the standard X\-axis and Y\-axis.
+Returns a list containing the X\-Y screen coordinates.
+.TP
+\fIpathName \fBxaxis \fIoperation\fR ?\fIarg\fR?...
+.TP
+\fIpathName \fBx2axis \fIoperation\fR ?\fIarg\fR?... 
+.TP
+\fIpathName \fByaxis \fIoperation\fR ?\fIarg\fR?... 
+.TP
+\fIpathName \fBy2axis \fIoperation\fR ?\fIarg\fR?... 
+See the 
+.SB "AXIS COMPONENTS"
+section.
+.SH "GRAPH COMPONENTS"
+A graph is composed of several components: coordinate axes, data
+elements, legend, grid, cross hairs, postscript, and annotation
+markers. Instead of one big set of configuration options and
+operations, the graph is partitioned, where each component has its own
+configuration options and operations that specifically control that
+aspect or part of the graph. 
+.SS "AXIS COMPONENTS"
+Four coordinate axes are automatically created: two X\-coordinate axes
+(\f(CWx\fR and \f(CWx2\fR) and two Y\-coordinate axes (\f(CWy\fR, and
+\f(CWy2\fR).  By default, the axis \f(CWx\fR is located in the bottom
+margin, \f(CWy\fR in the left margin, \f(CWx2\fR in the top margin, and
+\f(CWy2\fR in the right margin.
+.PP
+An axis consists of the axis line, title, major and minor ticks, and
+tick labels.  Major ticks are drawn at uniform intervals along the
+axis.  Each tick is labeled with its coordinate value.  Minor ticks
+are drawn at uniform intervals within major ticks.  
+.PP
+The range of the axis controls what region of data is plotted.
+Data points outside the minimum and maximum limits of the axis are
+not plotted.  By default, the minimum and maximum limits are
+determined from the data, but you can reset either limit.
+.PP
+You can have several axes. To create an axis, invoke
+the axis component and its create operation.
+.CS
+# Create a new axis called "tempAxis"
+\&.g axis create tempAxis
+.CE
+You map data elements to an axis using the element's \-mapy and \-mapx
+configuration options. They specify the coordinate axes an element
+is mapped onto.
+.CS
+# Now map the tempAxis data to this axis.
+\&.g element create "e1" \-xdata $x \-ydata $y \-mapy tempAxis
+.CE
+Any number of axes can be displayed simultaneously. They are drawn in
+the margins surrounding the plotting area.  The default axes \f(CWx\fR
+and \f(CWy\fR are drawn in the bottom and left margins. The axes
+\f(CWx2\fR and \f(CWy2\fR are drawn in top and right margins.  By
+default, only \f(CWx\fR and \f(CWy\fR are shown. Note that the axes
+can have different scales.
+.PP
+To display a different axis or more than one axis, you invoke one of
+the following components: \fBxaxis\fR, \fByaxis\fR, \fBx2axis\fR, and
+\fBy2axis\fR.  Each component has a \fBuse\fR operation that
+designates the axis (or axes) to be drawn in that corresponding
+margin: \fBxaxis\fR in the bottom, \fByaxis\fR in the left,
+\fBx2axis\fR in the top, and \fBy2axis\fR in the right.
+.CS
+# Display the axis tempAxis in the left margin.
+\&.g yaxis use tempAxis
+.CE
+The \fBuse\fR operation takes a list of axis names as its last
+argument.  This is the list of axes to be drawn in this margin.
+.PP
+You can configure axes in many ways. The axis scale can be linear or
+logarithmic.  The values along the axis can either monotonically
+increase or decrease.  If you need custom tick labels, you can specify
+a Tcl procedure to format the label any way you wish.  You can control
+how ticks are drawn, by changing the major tick interval or the number
+of minor ticks.  You can define non-uniform tick intervals, such as
+for time-series plots.
+.PP
+.TP
+\fIpathName \fBaxis bind \fItagName\fR ?\fIsequence\fR?  ?\fIcommand\fR? 
+Associates \fIcommand\fR with \fItagName\fR such that whenever the
+event sequence given by \fIsequence\fR occurs for an axis with this
+tag, \fIcommand\fR will be invoked.  The syntax is similar to the 
+\fBbind\fR command except that it operates on graph axes, rather 
+than widgets. See the \fBbind\fR manual entry for
+complete details on \fIsequence\fR and the substitutions performed on 
+\fIcommand\fR before invoking it.  
+.sp
+If all arguments are specified then a new binding is created, replacing 
+any existing binding for the same \fIsequence\fR and \fItagName\fR.
+If the first character of \fIcommand\fR is \f(CW+\fR then \fIcommand\fR 
+augments an existing binding rather than replacing it. 
+If no \fIcommand\fR argument is provided then the command currently
+associated with \fItagName\fR and \fIsequence\fR (it's an error occurs 
+if there's no such binding) is returned.  If both \fIcommand\fR and 
+\fIsequence\fR are missing then a list of all the event sequences for 
+which bindings have been defined for \fItagName\fR. 
+.TP
+\fIpathName \fBaxis \fBcget \fIaxisName \fIoption\fR
+Returns the current value of the option given by \fIoption\fR for
+\fIaxisName\fR.  \fIOption\fR may be any option described below
+for the axis \fBconfigure\fR operation.
+.TP
+\fIpathName \fBaxis \fBconfigure \fIaxisName \fR?\fIaxisName\fR?... ?\fIoption value\fR?...
+Queries or modifies the configuration options of \fIaxisName\fR.
+Several axes can be changed.  If \fIoption\fR isn't specified, a list
+describing all the current options for \fIaxisName\fR is returned.  If
+\fIoption\fR is specified, but not \fIvalue\fR, then a list describing
+\fIoption\fR is returned.  If one or more \fIoption\fR and \fIvalue\fR
+pairs are specified, then for each pair, the axis option \fIoption\fR
+is set to \fIvalue\fR.  The following options are valid for axes.
+.RS
+.TP
+\fB\-bindtags \fItagList\fR
+Specifies the binding tags for the axis.  \fITagList\fR is a list
+of binding tag names.  The tags and their order will determine how
+events for axes are handled.  Each tag in the list matching the current event
+sequence will have its Tcl command executed.  Implicitly the name of
+the element is always the first tag in the list.  The default value is
+\f(CWall\fR.
+.TP
+\fB\-color \fIcolor\fR
+Sets the color of the axis and tick labels.
+The default is \f(CWblack\fR.
+.TP
+\fB\-command \fIprefix\fR
+Specifies a Tcl command to be invoked when formatting the axis tick
+labels. \fIPrefix\fR is a string containing the name of a Tcl proc and
+any extra arguments for the procedure.  This command is invoked for each
+major tick on the axis.  Two additional arguments are passed to the
+procedure: the pathname of the widget and the current the numeric
+value of the tick.  The procedure returns the formatted tick label.  If
+\f(CW""\fR is returned, no label will appear next to the tick.  You can
+get the standard tick labels again by setting \fIprefix\fR to
+\f(CW""\fR.  The default is \f(CW""\fR.
+.sp 1
+Please note that this procedure is invoked while the graph is redrawn.
+You may query configuration options.  But do not them, because this
+can have unexpected results.
+.TP
+\fB\-descending \fIboolean\fR 
+Indicates whether the values along the axis are monotonically increasing or
+decreasing.  If \fIboolean\fR is true, the axis values will be
+decreasing.  The default is \f(CW0\fR.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates if the axis is displayed. If \fIboolean\fR is false the axis 
+will be displayed. Any element mapped to the axis is displayed regardless.
+The default value is \f(CW0\fR.
+.TP
+\fB\-justify \fIjustify\fR
+Specifies how the axis title should be justified.  This matters only
+when the axis title contains more than one line of text. \fIJustify\fR
+must be \f(CWleft\fR, \f(CWright\fR, or \f(CWcenter\fR.  The default is
+\f(CWcenter\fR.
+.TP
+\fB\-limits \fIformatStr\fR
+Specifies a printf-like description to format the minimum and maximum
+limits of the axis.  The limits are displayed at the top/bottom or
+left/right sides of the plotting area.  \fIFormatStr\fR is a list of
+one or two format descriptions.  If one description is supplied, both
+the minimum and maximum limits are formatted in the same way.  If two,
+the first designates the format for the minimum limit, the second for
+the maximum.  If \f(CW""\fR is given as either description, then 
+the that limit will not be displayed.  The default is \f(CW""\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of the axis and tick lines.  The default is \f(CW1\fR
+pixel.
+.TP
+\fB\-logscale \fIboolean\fR
+Indicates whether the scale of the axis is logarithmic or linear.  If
+\fIboolean\fR is true, the axis is logarithmic.  The default scale is
+linear.
+.TP
+\fB\-loose \fIboolean\fR
+Indicates whether the limits of the axis should fit the data points tightly,
+at the outermost data points, or loosely, at the outer tick intervals.
+If the axis limit is set with the -min or -max option, the axes are
+displayed tightly.
+If \fIboolean\fR is true, the axis range is "loose".
+The default is \f(CW0\fR.
+.TP
+\fB\-majorticks \fImajorList\fR
+Specifies where to display major axis ticks.  You can use this option
+to display ticks at non-uniform intervals.  \fIMajorList\fR is a list
+of axis coordinates designating the location of major ticks.  No
+minor ticks are drawn.  If \fImajorList\fR is \f(CW""\fR, 
+major ticks will be automatically computed. The default is \f(CW""\fR.
+.TP
+\fB\-max \fIvalue\fR
+Sets the maximum limit of \fIaxisName\fR.  Any data point greater 
+than \fIvalue\fR is not displayed.  If \fIvalue\fR is \f(CW""\fR, 
+the maximum limit is calculated using the largest data value.
+The default is \f(CW""\fR.
+.TP
+\fB\-min \fIvalue\fR
+Sets the minimum limit of \fIaxisName\fR. Any data point less than 
+\fIvalue\fR is not displayed.  If \fIvalue\fR is \f(CW""\fR,
+the minimum limit is calculated using the smallest data value.
+The default is \f(CW""\fR.
+.TP
+\fB\-minorticks \fIminorList\fR
+Specifies where to display minor axis ticks.  You can use this option
+to display minor ticks at non-uniform intervals. \fIMinorList\fR is a
+list of real values, ranging from 0.0 to 1.0, designating the placement of
+a minor tick.  No minor ticks are drawn if the \fB\-majortick\fR
+option is also set.  If \fIminorList\fR is \f(CW""\fR, minor ticks will
+be automatically computed. The default is \f(CW""\fR.
+.TP
+\fB\-rotate \fItheta\fR
+Specifies the how many degrees to rotate the axis tick labels.
+\fITheta\fR is a real value representing the number of degrees
+to rotate the tick labels.  The default is \f(CW0.0\fR degrees.
+.TP
+\fB\-scrollcommand \fIcommand\fR
+Specify the prefix for a command used to communicate with scrollbars
+for this axis, such as \fI.sbar set\fP.
+.TP
+\fB\-scrollmax \fIvalue\fR
+Sets the maximum limit of the axis scroll region.  If \fIvalue\fR is
+\f(CW""\fR, the maximum limit is calculated using the largest data
+value.  The default is \f(CW""\fR.
+.TP
+\fB\-scrollmin \fIvalue\fR 
+Sets the minimum limit of axis scroll region.  If \fIvalue\fR is
+\f(CW""\fR, the minimum limit is calculated using the smallest data
+value.  The default is \f(CW""\fR.
+.TP
+\fB\-showticks \fIboolean\fR
+Indicates whether axis ticks should be drawn. If \fIboolean\fR is
+true, ticks are drawn.  If false, only the
+axis line is drawn. The default is \f(CW1\fR.
+.TP
+\fB\-stepsize \fIvalue\fR
+Specifies the interval between major axis ticks.  If \fIvalue\fR isn't
+a valid interval (must be less than the axis range), 
+the request is ignored and the step size is automatically calculated.
+.TP
+\fB\-subdivisions \fInumber\fR 
+Indicates how many minor axis ticks are
+to be drawn.  For example, if \fInumber\fR is two, only one minor
+tick is drawn.  If \fInumber\fR is one, no minor ticks are
+displayed.  The default is \f(CW2\fR.
+.TP
+\fB\-tickfont \fIfontName\fR 
+Specifies the font for axis tick labels. The default is
+\f(CW*-Courier-Bold-R-Normal-*-100-*\fR.
+.TP
+\fB\-ticklength \fIpixels\fR
+Sets the length of major and minor ticks (minor ticks are half the
+length of major ticks). If \fIpixels\fR is less than zero, the axis
+will be inverted with ticks drawn pointing towards the plot.  The
+default is \f(CW0.1i\fR.
+.TP
+\fB\-title \fItext\fR
+Sets the title of the axis. If \fItext\fR is 
+\f(CW""\fR, no axis title will be displayed.  
+.TP
+\fB\-titlealternate \fIboolean\fR
+Indicates to display the axis title in its alternate location. 
+Normally the axis title is centered along the axis.  This option
+places the axis either to the right (horizontal axes) or above
+(vertical axes) the axis.  The default is \f(CW0\fR.
+.TP
+\fB\-titlecolor \fIcolor\fR
+Sets the color of the axis title. The default is \f(CWblack\fR.
+.TP
+\fB\-titlefont \fIfontName\fR 
+Specifies the font for axis title. The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-14-140-*\fR.
+.PP
+Axis configuration options may be also be set by the \fBoption\fR
+command.  The resource class is \f(CWAxis\fR.  The resource names
+are the names of the axes (such as \f(CWx\fR or \f(CWx2\fR).
+.CS
+option add *Graph.Axis.Color  blue
+option add *Graph.x.LogScale  true
+option add *Graph.x2.LogScale false
+.CE
+.RE
+.TP
+\fIpathName \fBaxis \fBcreate \fIaxisName \fR?\fIoption value\fR?...
+Creates a new axis by the name \fIaxisName\fR.  No axis by the same
+name can already exist. \fIOption\fR and \fIvalue\fR are described 
+in above in the axis \fBconfigure\fR operation.
+.TP
+\fIpathName \fBaxis \fBdelete \fR?\fIaxisName\fR?...
+Deletes the named axes. An axis is not really
+deleted until it is not longer in use, so it's safe to delete
+axes mapped to elements.
+.TP
+\fIpathName \fBaxis invtransform \fIaxisName value\fR
+Performs the inverse transformation, changing the screen coordinate
+\fIvalue\fR to a graph coordinate, mapping the value mapped to
+\fIaxisName\fR.  Returns the graph coordinate.
+.TP
+\fIpathName \fBaxis limits \fIaxisName\fR
+Returns a list of the minimum and maximum limits for \fIaxisName\fR.  The order
+of the list is \f(CWmin max\fR.
+.TP
+\fIpathName \fBaxis names \fR?\fIpattern\fR?...
+Returns a list of axes matching zero or more patterns.  If no
+\fIpattern\fR argument is give, the names of all axes are returned.
+.TP
+\fIpathName \fBaxis transform \fIaxisName value\fR
+Transforms the coordinate \fIvalue\fR to a screen coordinate by mapping
+the it to \fIaxisName\fR.  Returns the transformed screen coordinate.
+.TP
+\fIpathName \fBaxis view \fIaxisName\fR
+Change the viewable area of this axis. Use as an argument to a scrollbar's "\fI\-command\fR".
+.PP
+The default axes are \f(CWx\fR, \f(CWy\fR, \f(CWx2\fR, and \f(CWy2\fR.
+But you can display more than four axes simultaneously.  You can also
+swap in a different axis with \fBuse\fR operation of the special axis
+components: \fBxaxis\fR, \fBx2axis\fR, \fByaxis\fR, and \fBy2axis\fR.
+.CS
+\&.g create axis temp
+\&.g create axis time
+\&...
+\&.g xaxis use temp
+\&.g yaxis use time
+.CE
+Only the axes specified for use are displayed on the screen.
+.PP
+The \fBxaxis\fR, \fBx2axis\fR, \fByaxis\fR, and \fBy2axis\fR
+components operate on an axis location rather than a specific axis
+like the more general \fBaxis\fR component does.  They implicitly
+control the axis that is currently using to that location.  By
+default, \fBxaxis\fR uses the \f(CWx\fR axis, \fByaxis\fR uses
+\f(CWy\fR, \fBx2axis\fR uses \f(CWx2\fR, and \fBy2axis\fR uses
+\f(CWy2\fR.  When more than one axis is displayed in a margin, it
+represents the first axis displayed.
+.PP
+The following operations are available for axes. They mirror exactly
+the operations of the \fBaxis\fR component.  The \fIaxis\fR argument
+must be \fBxaxis\fR, \fBx2axis\fR, \fByaxis\fR, or \fBy2axis\fR.  This
+feature is deprecated since more than one axis can now be used a
+margin.  You should only use the \fBxaxis\fR, \fBx2axis\fR,
+\fByaxis\fR, and \fBy2axis\fR components with the \fBuse\fR operation.
+For all other operations, use the general \fBaxis\fR component
+instead.
+.TP
+\fIpathName \fIaxis \fBcget \fIoption\fR
+.TP
+\fIpathName \fIaxis \fBconfigure \fR?\fIoption value\fR?...
+.TP
+\fIpathName \fIaxis\fB invtransform \fIvalue\fR
+.TP
+\fIpathName \fIaxis \fBlimits\fR
+.TP
+\fIpathName \fIaxis\fB transform \fIvalue\fR
+.TP
+\fIpathName \fIaxis\fB use \fR?\fIaxisName\fR?  
+Designates the axis \fIaxisName\fR is to be displayed at this
+location.  \fIAxisName\fR can not be already in use at another location.  
+This command returns the name of the axis currently using this location.
+.SS "CROSSHAIRS COMPONENT"
+Cross hairs consist of two intersecting lines (one vertical and one horizontal)
+drawn completely across the plotting area.  They are used to position
+the mouse in relation to the coordinate axes.  Cross hairs differ from line
+markers in that they are implemented using XOR drawing primitives.
+This means that they can be quickly drawn and erased without redrawing
+the entire graph.
+.PP
+The following operations are available for cross hairs:
+.TP
+\fIpathName \fBcrosshairs cget \fIoption\fR
+Returns the current value of the cross hairs configuration option
+given by \fIoption\fR.  \fIOption\fR may be any option
+described below for the cross hairs \fBconfigure\fR operation.
+.TP
+\fIpathName \fBcrosshairs configure \fR?\fIoption value\fR?...  
+Queries or modifies the configuration options of the cross hairs.  If
+\fIoption\fR isn't specified, a list describing all the current
+options for the cross hairs is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is returned.
+If one or more \fIoption\fR and \fIvalue\fR pairs are specified, then
+for each pair, the cross hairs option \fIoption\fR is set to
+\fIvalue\fR.
+The following options are available for cross hairs.
+.RS
+.TP
+\fB\-color \fIcolor\fR 
+Sets the color of the cross hairs.  The default is \f(CWblack\fR.
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the cross hairs. \fIDashList\fR is a list of up
+to 11 numbers that alternately represent the lengths of the dashes
+and gaps on the cross hair lines.  Each number must be between 1 and
+255.  If \fIdashList\fR is \f(CW""\fR, the cross hairs will be solid
+lines.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether cross hairs are drawn. If \fIboolean\fR is true,
+cross hairs are not drawn.  The default is \f(CWyes\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Set the width of the cross hair lines.  The default is \f(CW1\fR.
+.TP
+\fB\-position \fIpos\fR 
+Specifies the screen position where the cross hairs intersect.
+\fIPos\fR must be in the form "\fI@x,y\fR", where \fIx\fR and \fIy\fR
+are the window coordinates of the intersection.
+.PP
+Cross hairs configuration options may be also be set by the
+\fBoption\fR command.  The resource name and class are
+\f(CWcrosshairs\fR and \f(CWCrosshairs\fR respectively.
+.CS
+option add *Graph.Crosshairs.LineWidth 2
+option add *Graph.Crosshairs.Color     red
+.CE
+.RE
+.TP
+\fIpathName \fBcrosshairs off\fR
+Turns off the cross hairs. 
+.TP
+\fIpathName \fBcrosshairs on\fR
+Turns on the display of the cross hairs.
+.TP
+\fIpathName \fBcrosshairs toggle\fR 
+Toggles the current state of the cross hairs, alternately mapping and
+unmapping the cross hairs.
+.SS "ELEMENT COMPONENTS"
+A data element represents a set of data.  It contains x and y vectors
+containing the coordinates of the data points.  Elements can be
+displayed with a symbol at each data point and lines connecting the
+points.  Elements also control the appearance of the data, such as the
+symbol type, line width, color etc.
+.PP
+When new data elements are created, they are automatically added to a
+list of displayed elements.   The display list controls what elements
+are drawn and in what order.  
+.PP
+The following operations are available for elements.
+.TP
+\fIpathName \fBelement activate \fIelemName \fR?\fIindex\fR?...
+Specifies the data points of element \fIelemName\fR to be drawn
+using active foreground and background colors.  \fIElemName\fR is the
+name of the element and \fIindex\fR is a number representing the index
+of the data point. If no indices are present then all data points
+become active.
+.TP
+\fIpathName \fBelement bind \fItagName\fR ?\fIsequence\fR?  ?\fIcommand\fR? 
+Associates \fIcommand\fR with \fItagName\fR such that whenever the
+event sequence given by \fIsequence\fR occurs for an element with this
+tag, \fIcommand\fR will be invoked.  The syntax is similar to the 
+\fBbind\fR command except that it operates on graph elements, rather 
+than widgets. See the \fBbind\fR manual entry for
+complete details on \fIsequence\fR and the substitutions performed on 
+\fIcommand\fR before invoking it.  
+.sp
+If all arguments are specified then a new binding is created, replacing 
+any existing binding for the same \fIsequence\fR and \fItagName\fR.
+If the first character of \fIcommand\fR is \f(CW+\fR then \fIcommand\fR 
+augments an existing binding rather than replacing it. 
+If no \fIcommand\fR argument is provided then the command currently
+associated with \fItagName\fR and \fIsequence\fR (it's an error occurs 
+if there's no such binding) is returned.  If both \fIcommand\fR and 
+\fIsequence\fR are missing then a list of all the event sequences for 
+which bindings have been defined for \fItagName\fR. 
+.TP
+\fIpathName \fBelement cget \fIelemName \fIoption\fR
+Returns the current value of the element configuration option given by 
+\fIoption\fR.  \fIOption\fR may be any of the options described below
+for the element \fBconfigure\fR operation.
+.TP
+\fIpathName \fBelement closest \fIx y\fR ?\fIoption value\fR?... ?\fIelemName\fR?...
+Searches for the data point closest to the window coordinates \fIx\fR
+and \fIy\fR.  By default, all elements are searched.  Hidden elements
+(see the \fB\-hide\fR option is false) are ignored.  You can limit the
+search by specifying only the elements you want to be considered. 
+\fIElemName\fR must be the name of an element that can not be hidden.
+It returns a key-value list containing the name of the closest element, 
+the index of the closest data point, and the graph-coordinates of the point. 
+Returns \f(CW""\fR, if no data point within the threshold distance 
+can be found. The following
+\fIoption\fR\-\fIvalue\fR pairs are available.
+.RS
+.TP
+\fB\-along \fIdirection\fR
+Search for the closest element using the following criteria:
+.RS
+.TP
+\f(CWx\fR
+Find closest element vertically from the given X-coordinate. 
+.TP
+\f(CWy\fR
+Find the closest element horizontally from the given Y-coordinate. 
+.TP
+\f(CWboth\fR
+Find the closest element for the given point (using both the X and Y
+coordinates).  
+.RE
+.TP
+\fB\-halo \fIpixels\fR
+Specifies a threshold distance where selected data points are ignored.
+\fIPixels\fR is a valid screen distance, such as \f(CW2\fR or \f(CW1.2i\fR.
+If this option isn't specified, then it defaults to the value of the
+graph's \fB\-halo\fR option.
+.TP
+\fB\-interpolate \fIstring\fR
+Indicates whether to consider projections that lie along the line segments 
+connecting data points when searching for the closest point.
+The default value is \f(CW0\fR. The values for \fIstring\fR are
+described below.
+.RS
+.TP 1.25i
+\f(CWno\fR 
+Search only for the closest data point.
+.TP
+\f(CWyes\fR
+Search includes projections that lie along the
+line segments connecting the data points.  
+.RE
+.RE
+.TP
+\fIpathName \fBelement configure \fIelemName \fR?\fIelemName\fR... ?\fIoption value\fR?...
+Queries or modifies the configuration options for elements.  Several
+elements can be modified at the same time. If \fIoption\fR isn't
+specified, a list describing all the current options for
+\fIelemName\fR is returned.  If \fIoption\fR is specified, but not
+\fIvalue\fR, then a list describing the option \fIoption\fR is
+returned.  If one or more \fIoption\fR and \fIvalue\fR pairs are
+specified, then for each pair, the element option \fIoption\fR is set
+to \fIvalue\fR.  The following options are valid for elements.
+.RS
+.TP
+\fB\-activepen \fIpenName\fR
+Specifies pen to use to draw active element.  If \fIpenName\fR is
+\f(CW""\fR, no active elements will be drawn.  The default is 
+\f(CWactiveLine\fR.
+.TP
+\fB\-areabackground \fIcolor\fR 
+Specifies the background color of the area under the curve. The
+background area color is drawn only for bitmaps (see the
+\fB\-areapattern\fR option).  If \fIcolor\fR is \f(CW""\fR, the
+background is transparent.  The default is \f(CWblack\fR.
+.TP
+\fB\-areaforeground \fIcolor\fR 
+Specifies the foreground color of the area under the curve. 
+The default is \f(CWblack\fR.
+.TP
+\fB\-areapattern \fIpattern\fR 
+Specifies how to fill the area under the curve.  \fIPattern\fR may be
+the name of a Tk bitmap, \f(CWsolid\fR, or \f(CW""\fR.  If "solid",
+then the area under the curve is drawn with the color designated by
+the \fB\-areaforeground\fR option.  If a bitmap, then the bitmap is
+stippled across the area.  Here the bitmap colors are controlled by the
+\fB\-areaforeground\fR and \fB\-areabackground\fR options.  If
+\fIpattern\fR is \f(CW""\fR, no filled area is drawn.  The default is
+\f(CW""\fR.
+.TP
+\fB\-areatile \fIimage\fR 
+Specifies the name of a Tk image to be used to tile the area under the
+curve.  This option supersedes the \fB\-areapattern\fR option.
+\fIImage\fR must be a photo image.  If \fIimage\fR is \f(CW""\fR, no
+tiling is performed.  The default is \f(CW""\fR.
+.TP
+\fB\-bindtags \fItagList\fR
+Specifies the binding tags for the element.  \fITagList\fR is a list
+of binding tag names.  The tags and their order will determine how
+events are handled for elements.  Each tag in the list matching the 
+current event
+sequence will have its Tcl command executed.  Implicitly the name of
+the element is always the first tag in the list.  The default value is
+\f(CWall\fR.
+.TP
+\fB\-color \fIcolor\fR 
+Sets the color of the traces connecting the data points.  
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of element line. \fIDashList\fR is a list of up to
+11 numbers that alternately represent the lengths of the dashes and
+gaps on the element line.  Each number must be between 1 and 255.  If
+\fIdashList\fR is \f(CW""\fR, the lines will be solid.
+.TP
+\fB\-data \fIcoordList\fR
+Specifies the X\-Y coordinates of the data.  \fICoordList\fR is a
+list of numeric expressions representing the X\-Y coordinate pairs
+of each data point.
+.TP
+\fB\-fill \fIcolor\fR 
+Sets the interior color of symbols.  If \fIcolor\fR is \f(CW""\fR, then
+the interior of the symbol is transparent.  If \fIcolor\fR is
+\f(CWdefcolor\fR, then the color will be the same as the \fB\-color\fR
+option.  The default is \f(CWdefcolor\fR.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether the element is displayed.  
+The default is \f(CWno\fR.
+.TP
+\fB\-label \fItext\fR
+Sets the element's label in the legend.  If \fItext\fR
+is \f(CW""\fR, the element will have no entry in the legend.
+The default label is the element's name. 
+.TP
+\fB\-linewidth \fIpixels\fR 
+Sets the width of the connecting lines between data points.  If
+\fIpixels\fR is \f(CW0\fR, no connecting lines will be drawn between
+symbols.  The default is \f(CW0\fR.
+.TP
+\fB\-mapx \fIxAxis\fR
+Selects the X\-axis to map the element's X\-coordinates onto.
+\fIXAxis\fR must be the name of an axis.  The default is \f(CWx\fR.
+.TP
+\fB\-mapy \fIyAxis\fR
+Selects the Y\-axis to map the element's Y\-coordinates onto.
+\fIYAxis\fR must be the name of an axis. The default is \f(CWy\fR.
+.TP
+\fB\-offdash \fIcolor\fR
+Sets the color of the stripes when traces are dashed (see the
+\fB\-dashes\fR option).  If \fIcolor\fR is \f(CW""\fR, then the "off"
+pixels will represent gaps instead of stripes.  If \fIcolor\fR is
+\f(CWdefcolor\fR, then the color will be the same as the \fB\-color\fR
+option.  The default is \f(CWdefcolor\fR.
+.TP
+\fB\-outline \fIcolor\fR 
+Sets the color or the outline around each symbol.  If \fIcolor\fR is
+\f(CW""\fR, then no outline is drawn. If \fIcolor\fR is \f(CWdefcolor\fR,
+then the color will be the same as the \fB\-color\fR option.  The
+default is \f(CWdefcolor\fR.
+.TP
+\fB\-pen \fIpenname\fR
+Set the pen to use for this element.
+.TP
+\fB\-outlinewidth \fIpixels\fR 
+Sets the width of the outline bordering each symbol.  If \fIpixels\fR
+is \f(CW0\fR, no outline will be drawn. The default is \f(CW1\fR.
+.TP
+\fB\-pixels \fIpixels\fR
+Sets the size of symbols.  If \fIpixels\fR is \f(CW0\fR, no symbols will
+be drawn.  The default is \f(CW0.125i\fR.
+.TP
+\fB\-scalesymbols \fIboolean\fR 
+If \fIboolean\fR is true, the size of the symbols
+drawn for \fIelemName\fR will change with scale of the X\-axis and Y\-axis.
+At the time this option is set, the current ranges of the axes are
+saved as the normalized scales (i.e scale factor is 1.0) and the
+element is drawn at its designated size (see the \fB\-pixels\fR
+option).  As the scale of the axes change, the symbol will be scaled
+according to the smaller of the X\-axis and Y\-axis scales.  If \fIboolean\fR
+is false, the element's symbols are drawn at the designated size,
+regardless of axis scales.  The default is \f(CW0\fR.
+.TP
+\fB\-smooth \fIsmooth\fR 
+Specifies how connecting line segments are drawn between data points.
+\fISmooth\fR can be either \f(CWlinear\fR, \f(CWstep\fR, \f(CWnatural\fR, or
+\f(CWquadratic\fR.  If \fIsmooth\fR is \f(CWlinear\fR, a single line
+segment is drawn, connecting both data points. When \fIsmooth\fR is
+\f(CWstep\fR, two line segments are drawn. The first is a horizontal
+line segment that steps the next X\-coordinate.  The second is a
+vertical line, moving to the next Y\-coordinate.  Both \fInatural\fR and
+\fIquadratic\fR generate multiple segments between data points.  If
+\fInatural\fR, the segments are generated using a cubic spline.  If
+\fIquadratic\fR, a quadratic spline is used.  The default is
+\fIlinear\fR.
+.TP
+\fB\-styles \fIstyleList\fR 
+Specifies what pen to use based on the range of weights given.
+\fIStyleList\fR is a list of style specifications. Each style
+specification, in turn, is a list consisting of a pen name, and
+optionally a minimum and maximum range.  Data points whose weight (see
+the \fB\-weight\fR option) falls in this range, are drawn with this
+pen.  If no range is specified it defaults to the index of the pen in
+the list.  Note that this affects only symbol attributes. Line
+attributes, such as line width, dashes, etc. are ignored.
+.TP
+\fB\-symbol \fIsymbol\fR 
+Specifies the symbol for data points.  \fISymbol\fR can be either
+\f(CWsquare\fR, \f(CWcircle\fR, \f(CWdiamond\fR, \f(CWplus\fR, \f(CWcross\fR,
+\f(CWsplus\fR, \f(CWscross\fR, \f(CWtriangle\fR, \f(CW""\fR (where no symbol
+is drawn), or a bitmap.  Bitmaps are specified as "\fIsource\fR
+?\fImask\fR?", where \fIsource\fR is the name of the bitmap, and
+\fImask\fR is the bitmap's optional mask.  The default is
+\f(CWcircle\fR.
+.TP
+\fB\-trace \fIdirection\fR 
+Indicates whether connecting lines between data points (whose
+X\-coordinate values are either increasing or decreasing) are drawn.  
+\fIDirection\fR
+must be \f(CWincreasing\fR, \f(CWdecreasing\fR, or \f(CWboth\fR.  For
+example, if \fIdirection\fR is \f(CWincreasing\fR, connecting lines will
+be drawn only between those data points where X\-coordinate values are
+monotonically increasing.  If \fIdirection\fR is \f(CWboth\fR,
+connecting lines will be draw between all data points.  The default is
+\f(CWboth\fR.
+.TP
+\fB\-weights \fIwVec\fR 
+Specifies the weights of the individual data points.  This, 
+with the list pen styles (see the \fB\-styles\fR option),
+controls how data points are drawn.  \fIWVec\fR is the name of a BLT
+vector or a list of numeric expressions representing the weights for
+each data point.
+.TP
+\fB\-xdata \fIxVec\fR 
+Specifies the X\-coordinates of the data.  \fIXVec\fR is the name of
+a BLT vector or a list of numeric expressions.
+.TP
+\fB\-ydata \fIyVec\fR 
+Specifies the Y\-coordinates of the data.  \fIYVec\fR is the name of
+a BLT vector or a list of numeric expressions.
+.PP
+Element configuration options may also be set by the \fBoption\fR
+command.  The resource class is \f(CWElement\fR. The resource name is
+the name of the element.
+.CS
+option add *Graph.Element.symbol line
+option add *Graph.e1.symbol line
+.CE
+.RE
+.TP
+\fIpathName \fBelement create \fIelemName\fR ?\fIoption value\fR?...
+Creates a new element \fIelemName\fR.  It's an error is
+an element \fIelemName\fR already exists.  If
+additional arguments are present, they specify options valid for 
+the element \fBconfigure\fR operation.
+.TP
+\fIpathName \fBelement deactivate \fIelemName\fR ?\fIelemName\fR?...
+Deactivates all the elements matching \fIpattern\fR.
+Elements whose names match any of the patterns given are redrawn using
+their normal colors.
+.TP
+\fIpathName \fBelement delete\fR ?\fIelemName\fR?...
+Deletes all the named elements.  The graph is automatically redrawn.
+.TP
+\fIpathName \fBelement exists \fIelemName\fR
+Returns \f(CW1\fR if an element \fIelemName\fR currently exists and
+\f(CW0\fR otherwise.
+.TP
+\fIpathName \fBelement names \fR?\fIpattern\fR?...  
+Returns the elements matching one or more pattern.  If no
+\fIpattern\fR is given, the names of all elements is returned.
+.TP
+\fIpathName \fBelement show\fR ?\fInameList\fR?  
+Queries or modifies the element display list.  The element display
+list designates the elements drawn and in what
+order. \fINameList\fR is a list of elements to be displayed in the
+order they are named.  If there is no \fInameList\fR argument,
+the current display list is returned.
+.TP
+\fIpathName \fBelement type\fR \fIelemName\fR
+Returns the type of \fIelemName\fR. 
+If the element is a bar element, the commands returns the string
+\f(CW"bar"\fR, otherwise it returns \f(CW"line"\fR.
+.CE
+.SS "GRID COMPONENT"
+Grid lines extend from the major and minor ticks of each axis
+horizontally or vertically across the plotting area.  The following
+operations are available for grid lines.
+.TP
+\fIpathName \fBgrid cget \fIoption\fR
+Returns the current value of the grid line configuration option given by 
+\fIoption\fR.  \fIOption\fR may be any option described below
+for the grid \fBconfigure\fR operation.
+.TP
+\fIpathName \fBgrid configure\fR ?\fIoption value\fR?...
+Queries or modifies the configuration options for grid lines.  If
+\fIoption\fR isn't specified, a list describing all the current
+grid options for \fIpathName\fR is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is
+returned.  If one or more \fIoption\fR and \fIvalue\fR pairs are
+specified, then for each pair, the grid line option \fIoption\fR is set to
+\fIvalue\fR.  The following options are valid for grid lines.
+.RS
+.TP
+\fB\-color \fIcolor\fR 
+Sets the color of the grid lines.  The default is \f(CWblack\fR.
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the grid lines. \fIDashList\fR is a list of up
+to 11 numbers that alternately represent the lengths of the dashes
+and gaps on the grid lines.  Each number must be between 1 and 255.
+If \fIdashList\fR is \f(CW""\fR, the grid will be solid lines.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether the grid should be drawn. If \fIboolean\fR
+is true, grid lines are not shown. The default is \f(CWyes\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of grid lines.  The default width is \f(CW1\fR.
+.TP
+\fB\-mapx \fIxAxis\fR
+Specifies the X\-axis to display grid lines.  \fIXAxis\fR
+must be the name of an axis or \f(CW""\fR for no grid lines.  
+The default is \f(CW""\fR.
+.TP
+\fB\-mapy \fIyAxis\fR
+Specifies the Y\-axis to display grid lines.  \fIYAxis\fR
+must be the name of an axis or \f(CW""\fR for no grid lines. 
+The default is \f(CWy\fR.
+.TP
+\fB\-minor \fIboolean\fR
+Indicates whether the grid lines should be drawn for minor ticks. 
+If \fIboolean\fR is true, the lines will appear at
+minor tick intervals.  The default is \f(CW1\fR.
+.PP
+Grid configuration options may also be set by the 
+\fBoption\fR command.  The resource name and class are \f(CWgrid\fR and 
+\f(CWGrid\fR respectively. 
+.CS
+option add *Graph.grid.LineWidth 2
+option add *Graph.Grid.Color     black
+.CE
+.RE
+.TP
+\fIpathName \fBgrid off\fR
+Turns off the display the grid lines.
+.TP
+\fIpathName \fBgrid on\fR
+Turns on the display the grid lines.
+.TP
+\fIpathName \fBgrid toggle\fR
+Toggles the display of the grid.  
+.SS "LEGEND COMPONENT"
+The legend displays a list of the data elements.  Each entry consists
+of the element's symbol and label.  The legend can appear in any
+margin (the default location is in the right margin).  It
+can also be positioned anywhere within the plotting area.
+.PP
+The following operations are valid for the legend.
+.TP
+\fIpathName \fBlegend activate \fIpattern\fR...
+Selects legend entries to be drawn using the active legend colors and relief.
+All entries whose element names match \fIpattern\fR  are selected.  To
+be selected, the element name must match only one \fIpattern\fR. 
+.TP
+\fIpathName \fBlegend bind \fItagName\fR ?\fIsequence\fR?  ?\fIcommand\fR? 
+Associates \fIcommand\fR with \fItagName\fR such that whenever the
+event sequence given by \fIsequence\fR occurs for a legend entry with this
+tag, \fIcommand\fR will be invoked.  Implicitly the element names
+in the entry are tags.  The syntax is similar to the 
+\fBbind\fR command except that it operates on legend entries, rather 
+than widgets. See the \fBbind\fR manual entry for
+complete details on \fIsequence\fR and the substitutions performed on 
+\fIcommand\fR before invoking it.  
+.sp
+If all arguments are specified then a new binding is created, replacing 
+any existing binding for the same \fIsequence\fR and \fItagName\fR.
+If the first character of \fIcommand\fR is \f(CW+\fR then \fIcommand\fR 
+augments an existing binding rather than replacing it. 
+If no \fIcommand\fR argument is provided then the command currently
+associated with \fItagName\fR and \fIsequence\fR (it's an error occurs 
+if there's no such binding) is returned.  If both \fIcommand\fR and 
+\fIsequence\fR are missing then a list of all the event sequences for 
+which bindings have been defined for \fItagName\fR. 
+.TP
+\fIpathName \fBlegend cget \fIoption\fR
+Returns the current value of a legend configuration option.
+\fIOption\fR may be any option described below in the
+legend \fBconfigure\fR operation.
+.TP
+\fIpathName \fBlegend configure \fR?\fIoption value\fR?...
+Queries or modifies the configuration options for the legend.  If
+\fIoption\fR isn't specified, a list describing the current
+legend options for \fIpathName\fR is returned.  If \fIoption\fR is
+specified, but not \fIvalue\fR, then a list describing \fIoption\fR is
+returned.  If one or more \fIoption\fR and \fIvalue\fR pairs are
+specified, then for each pair, the legend option \fIoption\fR is set
+to \fIvalue\fR.  The following options are valid for the legend.
+.RS
+.TP
+\fB\-activebackground \fIcolor\fR
+Sets the background color for active legend entries.  All legend
+entries marked active (see the legend \fBactivate\fR operation) are
+drawn using this background color.
+.TP
+\fB\-activeborderwidth \fIpixels\fR
+Sets the width of the 3-D border around the outside edge of the active legend
+entries.  The default is \f(CW2\fR.
+.TP
+\fB\-activeforeground \fIcolor\fR
+Sets the foreground color for active legend entries.  All legend
+entries marked as active (see the legend \fBactivate\fR operation) are
+drawn using this foreground color.
+.TP
+\fB\-activerelief \fIrelief\fR 
+Specifies the 3-D effect desired for active legend entries.
+\fIRelief\fR denotes how the interior of the entry should appear
+relative to the legend; for example, \f(CWraised\fR means the entry
+should appear to protrude from the legend, relative to the surface of
+the legend.  The default is \f(CWflat\fR.
+.TP
+\fB\-anchor \fIanchor\fR
+Tells how to position the legend relative to the positioning point for
+the legend.  This is dependent on the value of the \fB\-position\fR
+option.  The default is \f(CWcenter\fR.
+.RS
+.TP 1.25i
+\f(CWleft\fR or \f(CWright\fR
+The anchor describes how to position the legend vertically.  
+.TP
+\f(CWtop\fR or \f(CWbottom\fR
+The anchor describes how to position the legend horizontally.  
+.TP
+\f(CW@x,y\fR
+The anchor specifies how to position the legend relative to the
+positioning point. For example, if \fIanchor\fR is \f(CWcenter\fR then
+the legend is centered on the point; if \fIanchor\fR is \f(CWn\fR then
+the legend will be drawn such that the top center point of the
+rectangular region occupied by the legend will be at the positioning
+point.
+.TP
+\f(CWplotarea\fR
+The anchor specifies how to position the legend relative to the
+plotting area. For example, if \fIanchor\fR is \f(CWcenter\fR then the
+legend is centered in the plotting area; if \fIanchor\fR is \f(CWne\fR
+then the legend will be drawn such that occupies the upper right
+corner of the plotting area.
+.RE
+.TP
+\fB\-background \fIcolor\fR
+Sets the background color of the legend. If \fIcolor\fR is \f(CW""\fR,
+the legend background with be transparent.
+.TP
+\fB\-bindtags \fItagList\fR
+Specifies the binding tags for legend entries.  \fITagList\fR is a list
+of binding tag names.  The tags and their order will determine how
+events are handled for legend entries.  Each tag in the list matching 
+the current event sequence will have its Tcl command executed. The 
+default value is \f(CWall\fR.
+.TP
+\fB\-borderwidth \fIpixels\fR
+Sets the width of the 3-D border around the outside edge of the legend (if
+such border is being drawn; the \fBrelief\fR option determines this).
+The default is \f(CW2\fR pixels.
+.TP
+\fB\-font \fIfontName\fR 
+\fIFontName\fR specifies a font to use when drawing the labels of each
+element into the legend.  The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-12-120-*\fR.
+.TP
+\fB\-foreground \fIcolor\fR 
+Sets the foreground color of the text drawn for the element's label.
+The default is \f(CWblack\fR.
+.TP
+\fB\-hide \fIboolean\fR
+Indicates whether the legend should be displayed. If \fIboolean\fR is
+true, the legend will not be draw.  The default is \f(CWno\fR.
+.TP
+\fB\-ipadx \fIpad\fR 
+Sets the amount of internal padding to be added to the width of each
+legend entry.  \fIPad\fR can be a list of one or two screen distances.  If
+\fIpad\fR has two elements, the left side of the legend entry is
+padded by the first distance and the right side by the second.  If
+\fIpad\fR is just one distance, both the left and right sides are padded
+evenly.  The default is \f(CW2\fR.
+.TP
+\fB\-ipady \fIpad\fR
+Sets an amount of internal padding to be added to the height of each
+legend entry.  \fIPad\fR can be a list of one or two screen distances.  If
+\fIpad\fR has two elements, the top of the entry is padded by the
+first distance and the bottom by the second.  If \fIpad\fR is just
+one distance, both the top and bottom of the entry are padded evenly.
+The default is \f(CW2\fR.
+.TP
+\fB\-padx \fIpad\fR
+Sets the padding to the left and right exteriors of the legend.
+\fIPad\fR can be a list of one or two screen distances.  If \fIpad\fR
+has two elements, the left side of the legend is padded by the first
+distance and the right side by the second.  If \fIpad\fR has just one
+distance, both the left and right sides are padded evenly.  The
+default is \f(CW4\fR.
+.TP
+\fB\-pady \fIpad\fR
+Sets the padding above and below the legend.  \fIPad\fR can be a list
+of one or two screen distances.  If \fIpad\fR has two elements, the area above
+the legend is padded by the first distance and the area below by the
+second.  If \fIpad\fR is just one distance, both the top and
+bottom areas are padded evenly.  The default is \f(CW0\fR.
+.TP
+\fB\-position \fIpos\fR
+Specifies where the legend is drawn. The
+\fB\-anchor\fR option also affects where the legend is positioned.  If
+\fIpos\fR is \f(CWleft\fR, \f(CWleft\fR, \f(CWtop\fR, or \f(CWbottom\fR, the
+legend is drawn in the specified margin.  If \fIpos\fR is
+\f(CWplotarea\fR, then the legend is drawn inside the plotting area at a
+particular anchor.  If \fIpos\fR is in the form "\fI@x,y\fR", where
+\fIx\fR and \fIy\fR are the window coordinates, the legend is drawn in
+the plotting area at the specified coordinates.  The default is
+\f(CWright\fR.
+.TP
+\fB\-raised \fIboolean\fR
+Indicates whether the legend is above or below the data elements.  This
+matters only if the legend is in the plotting area.  If \fIboolean\fR
+is true, the legend will be drawn on top of any elements that may
+overlap it. The default is \f(CWno\fR.
+.TP
+\fB\-relief \fIrelief\fR
+Specifies the 3-D effect for the border around the legend.
+\fIRelief\fR specifies how the interior of the legend should appear
+relative to the graph; for example, \f(CWraised\fR means the legend
+should appear to protrude from the graph, relative to the surface of
+the graph.  The default is \f(CWsunken\fR.
+.PP
+Legend configuration options may also be set by the \fBoption\fR
+command.  The resource name and class are \f(CWlegend\fR and
+\f(CWLegend\fR respectively.
+.CS
+option add *Graph.legend.Foreground blue
+option add *Graph.Legend.Relief     raised
+.CE
+.RE
+.TP
+\fIpathName \fBlegend deactivate \fIpattern\fR...
+Selects legend entries to be drawn using the normal legend colors and
+relief.  All entries whose element names match \fIpattern\fR are
+selected.  To be selected, the element name must match only one
+\fIpattern\fR.
+.TP
+\fIpathName \fBlegend get \fIpos\fR
+Returns the name of the element whose entry is at the screen position
+\fIpos\fR in the legend.  \fIPos\fR must be in the form "\fI@x,y\fR",
+where \fIx\fR and \fIy\fR are window coordinates.  If the given
+coordinates do not lie over a legend entry, \f(CW""\fR is returned.
+.SS "PEN COMPONENTS"
+Pens define attributes (both symbol and line style) for elements.
+Pens mirror the configuration options of data elements that pertain to
+how symbols and lines are drawn.  Data elements use pens to determine
+how they are drawn.  A data element may use several pens at once.  In
+this case, the pen used for a particular data point is determined from
+each element's weight vector (see the element's \fB\-weight\fR and
+\fB\-style\fR options).
+.PP
+One pen, called \f(CWactiveLine\fR, is automatically created.
+It's used as the default active pen for elements. So you can change
+the active attributes for all elements by simply reconfiguring this
+pen.
+.CS
+\&.g pen configure "activeLine" -color green
+.CE
+You can create and use several pens. To create a pen, invoke
+the pen component and its create operation.
+.CS
+\&.g pen create myPen
+.CE
+You map pens to a data element using either the element's 
+\fB\-pen\fR or \fB\-activepen\fR options.
+.CS
+\&.g element create "line1" -xdata $x -ydata $tempData \\
+    -pen myPen
+.CE
+An element can use several pens at once. This is done by specifying
+the name of the pen in the element's style list (see the
+\fB\-styles\fR option).
+.CS
+\&.g element configure "line1" -styles { myPen 2.0 3.0 }
+.CE
+This says that any data point with a weight between 2.0 and 3.0
+is to be drawn using the pen \f(CWmyPen\fR.  All other points
+are drawn with the element's default attributes.
+.PP
+The following operations are available for pen components.
+.PP
+.TP
+\fIpathName \fBpen \fBcget \fIpenName \fIoption\fR
+Returns the current value of the option given by \fIoption\fR for
+\fIpenName\fR.  \fIOption\fR may be any option described below
+for the pen \fBconfigure\fR operation.
+.TP
+\fIpathName \fBpen \fBconfigure \fIpenName \fR?\fIpenName\fR... ?\fIoption value\fR?...
+Queries or modifies the configuration options of
+\fIpenName\fR. Several pens can be modified at once.  If \fIoption\fR
+isn't specified, a list describing the current options for
+\fIpenName\fR is returned.  If \fIoption\fR is specified, but not
+\fIvalue\fR, then a list describing \fIoption\fR is returned.  If one
+or more \fIoption\fR and \fIvalue\fR pairs are specified, then for
+each pair, the pen option \fIoption\fR is set to \fIvalue\fR.  The
+following options are valid for pens.
+.RS
+.TP
+\fB\-color \fIcolor\fR 
+Sets the color of the traces connecting the data points.  
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of element line. \fIDashList\fR is a list of up to
+11 numbers that alternately represent the lengths of the dashes and
+gaps on the element line.  Each number must be between 1 and 255.  If
+\fIdashList\fR is \f(CW""\fR, the lines will be solid.
+.TP
+\fB\-fill \fIcolor\fR 
+Sets the interior color of symbols.  If \fIcolor\fR is \f(CW""\fR, then
+the interior of the symbol is transparent.  If \fIcolor\fR is
+\f(CWdefcolor\fR, then the color will be the same as the \fB\-color\fR
+option.  The default is \f(CWdefcolor\fR.
+.TP
+\fB\-linewidth \fIpixels\fR 
+Sets the width of the connecting lines between data points.  If
+\fIpixels\fR is \f(CW0\fR, no connecting lines will be drawn between
+symbols.  The default is \f(CW0\fR.
+.TP
+\fB\-offdash \fIcolor\fR
+Sets the color of the stripes when traces are dashed (see the
+\fB\-dashes\fR option).  If \fIcolor\fR is \f(CW""\fR, then the "off"
+pixels will represent gaps instead of stripes.  If \fIcolor\fR is
+\f(CWdefcolor\fR, then the color will be the same as the \fB\-color\fR
+option.  The default is \f(CWdefcolor\fR.
+.TP
+\fB\-outline \fIcolor\fR 
+Sets the color or the outline around each symbol.  If \fIcolor\fR is
+\f(CW""\fR, then no outline is drawn. If \fIcolor\fR is \f(CWdefcolor\fR,
+then the color will be the same as the \fB\-color\fR option.  The
+default is \f(CWdefcolor\fR.
+.TP
+\fB\-outlinewidth \fIpixels\fR 
+Sets the width of the outline bordering each symbol.  If \fIpixels\fR
+is \f(CW0\fR, no outline will be drawn. The default is \f(CW1\fR.
+.TP
+\fB\-pixels \fIpixels\fR
+Sets the size of symbols.  If \fIpixels\fR is \f(CW0\fR, no symbols will
+be drawn.  The default is \f(CW0.125i\fR.
+.TP
+\fB\-symbol \fIsymbol\fR 
+Specifies the symbol for data points.  \fISymbol\fR can be either
+\f(CWsquare\fR, \f(CWcircle\fR, \f(CWdiamond\fR, \f(CWplus\fR, \f(CWcross\fR,
+\f(CWsplus\fR, \f(CWscross\fR, \f(CWtriangle\fR, \f(CW""\fR (where no symbol
+is drawn), or a bitmap.  Bitmaps are specified as "\fIsource\fR
+?\fImask\fR?", where \fIsource\fR is the name of the bitmap, and
+\fImask\fR is the bitmap's optional mask.  The default is
+\f(CWcircle\fR.
+.TP
+\fB\-type \fIelemType\fR 
+Specifies the type of element the pen is to be used with.
+This option should only be employed when creating the pen.  This
+is for those that wish to mix different types of elements (bars and
+lines) on the same graph.  The default type is "line".
+.PP
+Pen configuration options may be also be set by the \fBoption\fR
+command.  The resource class is \f(CWPen\fR.  The resource names
+are the names of the pens.
+.CS
+option add *Graph.Pen.Color  blue
+option add *Graph.activeLine.color  green
+.CE
+.RE
+.TP
+\fIpathName \fBpen \fBcreate \fIpenName \fR?\fIoption value\fR?...
+Creates a new pen by the name \fIpenName\fR.  No pen by the same
+name can already exist. \fIOption\fR and \fIvalue\fR are described 
+in above in the pen \fBconfigure\fR operation.
+.TP
+\fIpathName \fBpen \fBdelete \fR?\fIpenName\fR?...
+Deletes the named pens. A pen is not really
+deleted until it is not longer in use, so it's safe to delete
+pens mapped to elements.
+.TP
+\fIpathName \fBpen names \fR?\fIpattern\fR?...
+Returns a list of pens matching zero or more patterns.  If no
+\fIpattern\fR argument is give, the names of all pens are returned.
+.SS "POSTSCRIPT COMPONENT"
+The graph can generate encapsulated PostScript output.  There
+are several configuration options you can specify to control how the
+plot will be generated.  You can change the page dimensions and
+borders.  The plot itself can be scaled, centered, or rotated to
+landscape.  The PostScript output can be written directly to a file or
+returned through the interpreter.
+.PP
+The following postscript operations are available.
+.TP
+\fIpathName \fBpostscript cget \fIoption\fR 
+Returns the current value of the postscript option given by
+\fIoption\fR.  \fIOption\fR may be any option described
+below for the postscript \fBconfigure\fR operation.
+.TP
+\fIpathName \fBpostscript configure \fR?\fIoption value\fR?...
+Queries or modifies the configuration options for PostScript
+generation.  If \fIoption\fR isn't specified, a list describing 
+the current postscript options for \fIpathName\fR is returned.  If
+\fIoption\fR is specified, but not \fIvalue\fR, then a list describing
+\fIoption\fR is returned.  If one or more \fIoption\fR and \fIvalue\fR
+pairs are specified, then for each pair, the postscript option
+\fIoption\fR is set to \fIvalue\fR.  The following postscript options
+are available.
+.RS
+.TP
+\fB\-center \fIboolean\fR
+Indicates whether the plot should be centered on the PostScript page.  If
+\fIboolean\fR is false, the plot will be placed in the upper left
+corner of the page.  The default is \f(CW1\fR.
+.TP
+\fB\-colormap \fIvarName\fR
+\fIVarName\fR must be the name of a global array variable that
+specifies a color mapping from the X color name to PostScript.  Each
+element of \fIvarName\fR must consist of PostScript code to set a
+particular color value (e.g. ``\f(CW1.0 1.0 0.0 setrgbcolor\fR'').  When
+generating color information in PostScript, the array variable \fIvarName\fR
+is checked if an element of the name as the color exists. If so, it uses 
+its value as the PostScript
+command to set the color.  If this option hasn't been specified, or if
+there isn't an entry in \fIvarName\fR for a given color, then it uses
+the red, green, and blue intensities from the X color.
+.TP
+\fB\-colormode \fImode\fR
+Specifies how to output color information.  \fIMode\fR must be either
+\f(CWcolor\fR (for full color output), \f(CWgray\fR (convert all colors to
+their gray-scale equivalents) or \f(CWmono\fR (convert foreground colors
+to black and background colors to white).  The default mode is
+\f(CWcolor\fR. 
+.TP
+\fB\-fontmap \fIvarName\fR
+\fIVarName\fR must be the name of a global array variable that
+specifies a font mapping from the X font name to PostScript.  Each
+element of \fIvarName\fR must consist of a Tcl list with one or two
+elements; the name and point size of a PostScript font.
+When outputting PostScript commands for a particular font, the array
+variable \fIvarName\fR is checked to see if an element by the 
+specified font exists.  If there is such an element, then the font
+information contained in that element is used in the PostScript
+output.  (If the point size is omitted from the list, the point size
+of the X font is used).  Otherwise the X font is examined in an
+attempt to guess what PostScript font to use.  This works only for
+fonts whose foundry property is \fIAdobe\fR (such as Times, Helvetica,
+Courier, etc.).  If all of this fails then the font defaults to
+\f(CWHelvetica-Bold\fR.
+.TP
+\fB\-decorations \fIboolean\fR
+Indicates whether PostScript commands to generate color backgrounds and 3-D
+borders will be output.  If \fIboolean\fR is false, the background will be 
+white and no 3-D borders will be generated. The
+default is \f(CW1\fR.
+.TP
+\fB\-height \fIpixels\fR
+Sets the height of the plot.  This lets you print the graph with a
+height different from the one drawn on the screen.  If
+\fIpixels\fR is 0, the height is the same as the widget's height.
+The default is \f(CW0\fR.
+.TP
+\fB\-landscape \fIboolean\fR
+If \fIboolean\fR is true, this specifies the printed area is to be
+rotated 90 degrees.  In non-rotated output the X\-axis of the printed
+area runs along the short dimension of the page (``portrait''
+orientation); in rotated output the X\-axis runs along the long
+dimension of the page (``landscape'' orientation).  Defaults to
+\f(CW0\fR.
+.TP
+\fB\-maxpect \fIboolean\fR
+Indicates to scale the plot so that it fills the PostScript page.
+The aspect ratio of the graph is still retained.  The default is
+\f(CW0\fR.
+.TP
+\fB\-padx \fIpad\fR
+Sets the horizontal padding for the left and right page borders.  The
+borders are exterior to the plot.  \fIPad\fR can be a list of one or
+two screen distances.  If \fIpad\fR has two elements, the left border is padded
+by the first distance and the right border by the second.  If
+\fIpad\fR has just one distance, both the left and right borders are
+padded evenly.  The default is \f(CW1i\fR.
+.TP
+\fB\-pady \fIpad\fR 
+Sets the vertical padding for the top and bottom page borders. The
+borders are exterior to the plot.  \fIPad\fR can be a list of one or
+two screen distances.  If \fIpad\fR has two elements, the top border is padded
+by the first distance and the bottom border by the second.  If
+\fIpad\fR has just one distance, both the top and bottom borders are
+padded evenly.  The default is \f(CW1i\fR.
+.TP
+\fB\-paperheight \fIpixels\fR
+Sets the height of the postscript page.  This can be used to select
+between different page sizes (letter, A4, etc).  The default height is
+\f(CW11.0i\fR.
+.TP
+\fB\-paperwidth \fIpixels\fR
+Sets the width of the postscript page.  This can be used to select
+between different page sizes (letter, A4, etc).  The default width is
+\f(CW8.5i\fR.
+.TP
+\fB\-width \fIpixels\fR
+Sets the width of the plot.  This lets you generate a plot
+of a width different from that of the widget.  If \fIpixels\fR
+is 0, the width is the same as the widget's width.  The default is
+\f(CW0\fR.
+.PP
+Postscript configuration options may be also be set by the
+\fBoption\fR command.  The resource name and class are
+\f(CWpostscript\fR and \f(CWPostscript\fR respectively.
+.CS
+option add *Graph.postscript.Decorations false
+option add *Graph.Postscript.Landscape   true
+.CE
+.RE
+.TP
+\fIpathName \fBpostscript output \fR?\fIfileName\fR? ?\fIoption value\fR?...
+Outputs a file of encapsulated PostScript.  If a
+\fIfileName\fR argument isn't present, the command returns the
+PostScript. If any \fIoption-value\fR pairs are present, they set
+configuration options controlling how the PostScript is generated.
+\fIOption\fR and \fIvalue\fR can be anything accepted by the
+postscript \fBconfigure\fR operation above.
+.SS "MARKER COMPONENTS"
+Markers are simple drawing procedures used to annotate or highlight
+areas of the graph.  Markers have various types: text strings,
+bitmaps, images, connected lines, windows, or polygons.  They can be
+associated with a particular element, so that when the element is
+hidden or un-hidden, so is the marker.  By default, markers are the
+last items drawn, so that data elements will appear in
+behind them.  You can change this by configuring the \fB\-under\fR
+option.
+.PP
+Markers, in contrast to elements, don't affect the scaling of the
+coordinate axes.  They can also have \fIelastic\fR coordinates
+(specified by \f(CW-Inf\fR and \f(CWInf\fR respectively) that translate
+into the minimum or maximum limit of the axis.  For example, you can
+place a marker so it always remains in the lower left corner of the
+plotting area, by using the coordinates \f(CW-Inf\fR,\f(CW-Inf\fR.
+.PP
+The following operations are available for markers.
+.TP
+\fIpathName \fBmarker after \fImarkerId\fR ?\fIafterId\fR?
+Changes the order of the markers, drawing the first
+marker after the second.  If no second \fIafterId\fR argument is
+specified, the marker is placed at the end of the display list.  This
+command can be used to control how markers are displayed since markers
+are drawn in the order of this display list.
+.TP
+\fIpathName \fBmarker before \fImarkerId\fR ?\fIbeforeId\fR?
+Changes the order of the markers, drawing the first
+marker before the second.  If no second \fIbeforeId\fR argument is
+specified, the marker is placed at the beginning of the display list.
+This command can be used to control how markers are displayed since
+markers are drawn in the order of this display list.
+.TP
+\fIpathName \fBmarker bind \fItagName\fR ?\fIsequence\fR?  ?\fIcommand\fR? 
+Associates \fIcommand\fR with \fItagName\fR such that whenever the
+event sequence given by \fIsequence\fR occurs for a marker with this
+tag, \fIcommand\fR will be invoked.  The syntax is similar to the 
+\fBbind\fR command except that it operates on graph markers, rather 
+than widgets. See the \fBbind\fR manual entry for
+complete details on \fIsequence\fR and the substitutions performed on 
+\fIcommand\fR before invoking it.  
+.sp
+If all arguments are specified then a new binding is created, replacing 
+any existing binding for the same \fIsequence\fR and \fItagName\fR.
+If the first character of \fIcommand\fR is \f(CW+\fR then \fIcommand\fR 
+augments an existing binding rather than replacing it. 
+If no \fIcommand\fR argument is provided then the command currently
+associated with \fItagName\fR and \fIsequence\fR (it's an error occurs 
+if there's no such binding) is returned.  If both \fIcommand\fR and 
+\fIsequence\fR are missing then a list of all the event sequences for 
+which bindings have been defined for \fItagName\fR. 
+.TP
+\fIpathName \fBmarker cget \fIoption\fR
+Returns the current value of the marker configuration option given by
+\fIoption\fR.  \fIOption\fR may be any option described
+below in the \fBconfigure\fR operation.
+.TP
+\fIpathName \fBmarker configure \fImarkerId\fR ?\fIoption value\fR?...
+Queries or modifies the configuration options for markers.  If
+\fIoption\fR isn't specified, a list describing the current
+options for \fImarkerId\fR is returned.  If \fIoption\fR is specified,
+but not \fIvalue\fR, then a list describing \fIoption\fR is returned.
+If one or more \fIoption\fR and \fIvalue\fR pairs are specified, then
+for each pair, the marker option \fIoption\fR is set to \fIvalue\fR.
+.sp
+The following options are valid for all markers.
+Each type of marker also has its own type-specific options.  
+They are described in the sections below.
+.RS
+.TP
+\fB\-bindtags \fItagList\fR
+Specifies the binding tags for the marker.  \fITagList\fR is a list
+of binding tag names.  The tags and their order will determine how
+events for markers are handled.  Each tag in the list matching the 
+current event sequence will have its Tcl command executed.  Implicitly 
+the name of the marker is always the first tag in the list.
+The default value is \f(CWall\fR.
+.TP
+\fB\-coords \fIcoordList\fR
+Specifies the coordinates of the marker.  \fICoordList\fR is 
+a list of graph coordinates.  The number of coordinates required
+is dependent on the type of marker.  Text, image, and window markers
+need only two coordinates (an X\-Y coordinate).   Bitmap markers
+can take either two or four coordinates (if four, they represent the
+corners of the bitmap). Line markers
+need at least four coordinates, polygons at least six.
+If \fIcoordList\fR is \f(CW""\fR, the marker will not be displayed.
+The default is \f(CW""\fR.
+.TP
+\fB\-element \fIelemName\fR
+Links the marker with the element \fIelemName\fR.  The marker is
+drawn only if the element is also currently displayed (see the
+element's \fBshow\fR operation).  If \fIelemName\fR is \f(CW""\fR, the
+marker is always drawn.  The default is \f(CW""\fR.
+.TP
+\fB\-hide \fIboolean\fR 
+Indicates whether the marker is drawn. If \fIboolean\fR is true,
+the marker is not drawn.  The default is \f(CWno\fR.
+.TP
+\fB\-mapx \fIxAxis\fR 
+Specifies the X\-axis to map the marker's X\-coordinates onto.
+\fIXAxis\fR must the name of an axis.  The default is \f(CWx\fR.
+.TP
+\fB\-mapy \fIyAxis\fR
+Specifies the Y\-axis to map the marker's Y\-coordinates onto.
+\fIYAxis\fR must the name of an axis.  The default is \f(CWy\fR.
+.TP
+\fB\-name \fImarkerId\fR
+Changes the identifier for the marker.  The identifier \fImarkerId\fR 
+can not already be used by another marker.  If this option
+isn't specified, the marker's name is uniquely generated.
+.TP
+\fB\-under \fIboolean\fR
+Indicates whether the marker is drawn below/above data
+elements.  If \fIboolean\fR is true, the marker is be drawn
+underneath the data element symbols and lines.  Otherwise, the marker is
+drawn on top of the element.  The default is \f(CW0\fR.
+.TP
+\fB\-xoffset \fIpixels\fR
+Specifies a screen distance to offset the marker horizontally. 
+\fIPixels\fR is a valid screen distance, such as \f(CW2\fR or \f(CW1.2i\fR.
+The default is \f(CW0\fR.
+.TP
+\fB\-yoffset \fIpixels\fR
+Specifies a screen distance to offset the markers vertically.
+\fIPixels\fR is a valid screen distance, such as \f(CW2\fR or \f(CW1.2i\fR.
+The default is \f(CW0\fR.
+.PP
+Marker configuration options may also be set by the \fBoption\fR command.
+The resource class is either \f(CWBitmapMarker\fR,  \f(CWImageMarker\fR, 
+\f(CWLineMarker\fR, \f(CWPolygonMarker\fR, \f(CWTextMarker\fR, or \f(CWWindowMarker\fR,
+depending on the type of marker.  The resource name is the name of the
+marker.
+.CS
+option add *Graph.TextMarker.Foreground white
+option add *Graph.BitmapMarker.Foreground white
+option add *Graph.m1.Background     blue
+.CE
+.RE
+.TP
+\fIpathName \fBmarker create \fItype\fR ?\fIoption value\fR?...
+Creates a marker of the selected type. \fIType\fR may be either
+\f(CWtext\fR, \f(CWline\fR, \f(CWbitmap\fR, \f(CWimage\fR, \f(CWpolygon\fR, or
+\f(CWwindow\fR.  This command returns the marker identifier, 
+used as the \fImarkerId\fR argument in the other marker-related
+commands.  If the \fB\-name\fR option is used, this overrides the
+normal marker identifier.  If the name provided is already used for
+another marker, the new marker will replace the old.
+.TP
+\fIpathName \fBmarker delete\fR ?\fIname\fR?...
+Removes one of more markers.  The graph will automatically be redrawn
+without the marker.\fR.  
+.TP
+\fIpathName \fBmarker exists \fImarkerId\fR 
+Returns \f(CW1\fR if the marker \fImarkerId\fR exists and \f(CW0\fR
+otherwise.
+.TP
+\fIpathName \fBmarker names\fR ?\fIpattern\fR?  
+Returns the names of all the markers that currently exist.  If
+\fIpattern\fR is supplied, only those markers whose names match it
+will be returned.
+.TP
+\fIpathName \fBmarker type \fImarkerId\fR 
+Returns the type of the marker given by \fImarkerId\fR, such as
+\f(CWline\fR or \f(CWtext\fR.  If \fImarkerId\fR is not a valid a marker
+identifier, \f(CW""\fR is returned.
+.SS "BITMAP MARKERS"
+A bitmap marker displays a bitmap.  The size of the
+bitmap is controlled by the number of coordinates specified.  If two
+coordinates, they specify the position of the top-left corner of the
+bitmap.  The bitmap retains its normal width and height.  If four
+coordinates, the first and second pairs of coordinates represent the
+corners of the bitmap.  The bitmap will be stretched or reduced as
+necessary to fit into the bounding rectangle.
+.PP
+Bitmap markers are created with the marker's \fBcreate\fR operation in
+the form:
+.DS
+\fIpathName \fBmarker create bitmap \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR pairs, each 
+sets a configuration options for the marker.  These
+same \fIoption\fR\-\fIvalue\fR pairs may be used with the marker's
+\fBconfigure\fR operation.
+.PP
+The following options are specific to bitmap markers:
+.TP
+\fB\-background \fIcolor\fR
+Same as the \fB\-fill\fR option.
+.TP
+\fB\-bitmap \fIbitmap\fR
+Specifies the bitmap to be displayed.  If \fIbitmap\fR is \f(CW""\fR,
+the marker will not be displayed.  The default is \f(CW""\fR.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the background color of the bitmap.  If \fIcolor\fR is the empty
+string, no background will be transparent.  The default background color is
+\f(CW""\fR.
+.TP
+\fB\-foreground \fIcolor\fR 
+Same as the \fB\-outline\fR option.
+.TP
+\fB\-mask \fImask\fR
+Specifies a mask for the bitmap to be displayed. This mask is a bitmap
+itself, denoting the pixels that are transparent.  If \fImask\fR is
+\f(CW""\fR, all pixels of the bitmap will be drawn.  The default is
+\f(CW""\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the foreground color of the bitmap. The default value is \f(CWblack\fR.
+.TP
+\fB\-rotate \fItheta\fR
+Sets the rotation of the bitmap.  \fITheta\fR is a real number
+representing the angle of rotation in degrees.  The marker is first
+rotated and then placed according to its anchor position.  The default
+rotation is \f(CW0.0\fR.
+.SS "IMAGE MARKERS"
+A image marker displays an image.  Image markers are
+created with the marker's \fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create image \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR\-\fIvalue\fR pairs may be
+used with the marker's \fBconfigure\fR operation.
+.PP
+The following options are specific to image markers:
+.TP
+\fB\-anchor \fIanchor\fR
+\fIAnchor\fR tells how to position the image relative to the
+positioning point for the image. For example, if \fIanchor\fR
+is \f(CWcenter\fR then the image is centered on the point;  if
+\fIanchor\fR is \f(CWn\fR then the image will be drawn such that
+the top center point of the rectangular region occupied by the
+image will be at the positioning point.
+This option defaults to \f(CWcenter\fR.
+.TP
+\fB\-image \fIimage\fR
+Specifies the image to be drawn.
+If \fIimage\fR is \f(CW""\fR, the marker will not be
+drawn.  The default is \f(CW""\fR.
+.SS "LINE MARKERS"
+A line marker displays one or more connected line segments.
+Line markers are created with marker's \fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create line \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR-\fIvalue\fR pairs may be
+used with the marker's \fBconfigure\fR operation.
+.PP
+The following options are specific to line markers:
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the line. \fIDashList\fR is a list of up to 11
+numbers that alternately represent the lengths of the dashes and gaps
+on the line.  Each number must be between 1 and 255.  If
+\fIdashList\fR is \f(CW""\fR, the marker line will be solid.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the background color of the line.  This color is used with
+striped lines (see the \fB\-fdashes\fR option). If \fIcolor\fR is
+the empty string, no background color is drawn (the line will be
+dashed, not striped).  The default background color is \f(CW""\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of the lines.
+The default width is \f(CW0\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the foreground color of the line. The default value is \f(CWblack\fR.
+.TP
+\fB\-stipple \fIbitmap\fR
+Specifies a stipple pattern used to draw the line, rather than
+a solid line.
+\fIBitmap\fR specifies a bitmap to use as the stipple
+pattern.  If \fIbitmap\fR is \f(CW""\fR, then the
+line is drawn in a solid fashion. The default is \f(CW""\fR.
+.SS "POLYGON MARKERS"
+A polygon marker displays a closed region described as two or more
+connected line segments.  It is assumed the first and
+last points are connected.  Polygon markers are created using the
+marker \fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create polygon \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR\-\fIvalue\fR pairs may be
+used with the \fBmarker configure\fR command to change the marker's
+configuration.
+The following options are supported for polygon markers:
+.TP
+\fB\-dashes \fIdashList\fR
+Sets the dash style of the outline of the polygon. \fIDashList\fR is a
+list of up to 11 numbers that alternately represent the lengths of
+the dashes and gaps on the outline.  Each number must be between 1 and
+255. If \fIdashList\fR is \f(CW""\fR, the outline will be a solid line.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the fill color of the polygon.  If \fIcolor\fR is \f(CW""\fR, then
+the interior of the polygon is transparent.
+The default is \f(CWwhite\fR.
+.TP
+\fB\-linewidth \fIpixels\fR
+Sets the width of the outline of the polygon. If \fIpixels\fR is zero, 
+no outline is drawn. The default is \f(CW0\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the color of the outline of the polygon.  If the polygon is
+stippled (see the \fB\-stipple\fR option), then this represents the
+foreground color of the stipple.  The default is \f(CWblack\fR.
+.TP
+\fB\-stipple \fIbitmap\fR
+Specifies that the polygon should be drawn with a stippled pattern
+rather than a solid color. \fIBitmap\fR specifies a bitmap to use as
+the stipple pattern.  If \fIbitmap\fR is \f(CW""\fR, then the polygon is
+filled with a solid color (if the \fB\-fill\fR option is set).  The
+default is \f(CW""\fR.
+.SS "TEXT MARKERS"
+A text marker displays a string of characters on one or more lines of
+text.  Embedded newlines cause line breaks.  They may be used to
+annotate regions of the graph.  Text markers are created with the
+\fBcreate\fR operation in the form:
+.DS
+\fIpathName \fBmarker create text \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR pairs, 
+each sets a configuration option for the text marker.  
+These same \fIoption\fR\-\fIvalue\fR pairs may be used with the 
+marker's \fBconfigure\fR operation.  
+.PP
+The following options are specific to text markers:
+.TP
+\fB\-anchor \fIanchor\fR
+\fIAnchor\fR tells how to position the text relative to the
+positioning point for the text. For example, if \fIanchor\fR is
+\f(CWcenter\fR then the text is centered on the point; if
+\fIanchor\fR is \f(CWn\fR then the text will be drawn such that the
+top center point of the rectangular region occupied by the text will
+be at the positioning point.  This default is \f(CWcenter\fR.
+.TP
+\fB\-background \fIcolor\fR
+Same as the \fB\-fill\fR option.
+.TP
+\fB\-font \fIfontName\fR
+Specifies the font of the text.  The default is
+\f(CW*-Helvetica-Bold-R-Normal-*-120-*\fR.
+.TP
+\fB\-fill \fIcolor\fR
+Sets the background color of the text.  If \fIcolor\fR is the empty
+string, no background will be transparent.  The default background color is
+\f(CW""\fR.
+.TP
+\fB\-foreground \fIcolor\fR
+Same as the \fB\-outline\fR option.
+.TP
+\fB\-justify \fIjustify\fR
+Specifies how the text should be justified.  This matters only when
+the marker contains more than one line of text. \fIJustify\fR must be
+\f(CWleft\fR, \f(CWright\fR, or \f(CWcenter\fR.  The default is
+\f(CWcenter\fR.
+.TP
+\fB\-outline \fIcolor\fR
+Sets the color of the text. The default value is \f(CWblack\fR.
+.TP
+\fB\-padx \fIpad\fR
+Sets the padding to the left and right exteriors of the text.
+\fIPad\fR can be a list of one or two screen distances.  If \fIpad\fR
+has two elements, the left side of the text is padded by the first
+distance and the right side by the second.  If \fIpad\fR has just one
+distance, both the left and right sides are padded evenly.  The
+default is \f(CW4\fR.
+.TP
+\fB\-pady \fIpad\fR
+Sets the padding above and below the text.  \fIPad\fR can be a list of
+one or two screen distances.  If \fIpad\fR has two elements, the area above the
+text is padded by the first distance and the area below by the second.
+If \fIpad\fR is just one distance, both the top and bottom areas
+are padded evenly.  The default is \f(CW4\fR.
+.TP
+\fB\-rotate \fItheta\fR
+Specifies the number of degrees to rotate the text.  \fITheta\fR is a
+real number representing the angle of rotation.  The marker is first
+rotated along its center and is then drawn according to its anchor
+position. The default is \f(CW0.0\fR.
+.TP
+\fB\-text \fItext\fR
+Specifies the text of the marker.  The exact way the text is
+displayed may be affected by other options such as \fB\-anchor\fR or
+\fB\-rotate\fR.
+.SS "WINDOW MARKERS"
+A window marker displays a widget at a given position.
+Window markers are created with the marker's \fBcreate\fR operation in
+the form:
+.DS
+\fIpathName \fBmarker create window \fR?\fIoption value\fR?...
+.DE
+There may be many \fIoption\fR-\fIvalue\fR
+pairs, each sets a configuration option
+for the marker.  These same \fIoption\fR\-\fIvalue\fR pairs may be
+used with the marker's \fBconfigure\fR command.
+.PP
+The following options are specific to window markers:
+.TP
+\fB\-anchor \fIanchor\fR
+\fIAnchor\fR tells how to position the widget relative to the
+positioning point for the widget. For example, if \fIanchor\fR is
+\f(CWcenter\fR then the widget is centered on the point; if \fIanchor\fR
+is \f(CWn\fR then the widget will be displayed such that the top center
+point of the rectangular region occupied by the widget will be at the
+positioning point.  This option defaults to \f(CWcenter\fR.
+.TP
+\fB\-height \fIpixels\fR
+Specifies the height to assign to the marker's window.  If this option
+isn't specified, or if it is specified as \f(CW""\fR, then the window is
+given whatever height the widget requests internally.
+.TP
+\fB\-width \fIpixels\fR
+Specifies the width to assign to the marker's window.  If this option
+isn't specified, or if it is specified as \f(CW""\fR, then the window is
+given whatever width the widget requests internally.
+.TP
+\fB\-window \fIpathName\fR
+Specifies the widget to be managed by the graph.  \fIPathName\fR must
+be a child of the \fBgraph\fR widget.
+.SH "GRAPH COMPONENT BINDINGS"
+Specific graph components, such as elements, markers and legend
+entries, can have a command trigger when event occurs in them, much
+like canvas items in Tk's canvas widget.  Not all event sequences are
+valid.  The only binding events that may be specified are those
+related to the mouse and keyboard (such as \fBEnter\fR, \fBLeave\fR,
+\fBButtonPress\fR, \fBMotion\fR, and \fBKeyPress\fR).
+.PP
+Only one element or marker can be picked during an event.  This means,
+that if the mouse is directly over both an element and a marker, only
+the uppermost component is selected.  This isn't true for legend entries.  
+Both a legend entry and an element (or marker) binding commands 
+will be invoked if both items are picked.
+.PP
+It is possible for multiple bindings to match a particular event.
+This could occur, for example, if one binding is associated with the
+element name and another is associated with one of the element's tags
+(see the \fB\-bindtags\fR option).  When this occurs, all of the 
+matching bindings are invoked.  A binding associated with the element
+name is invoked first, followed by one binding for each of the element's 
+bindtags.  If there are multiple matching bindings for a single tag, 
+then only the most specific binding is invoked.  A continue command 
+in a binding script terminates that script, and a break command 
+terminates that script and skips any remaining scripts for the event, 
+just as for the bind command.
+.PP
+The \fB\-bindtags\fR option for these components controls addition
+tag names which can be matched.  Implicitly elements and markers
+always have tags matching their names.  Setting the value of
+the \fB\-bindtags\fR option doesn't change this.
+.SH "C LANGUAGE API"
+You can manipulate data elements from the C language.  There
+may be situations where it is too expensive to translate the data
+values from ASCII strings.  Or you might want to read data in a
+special file format.
+.PP
+Data can manipulated from the C language using BLT vectors.
+You specify the X-Y data coordinates of an element as vectors and
+manipulate the vector from C.  The graph will be redrawn automatically
+after the vectors are updated.
+.PP
+From Tcl, create the vectors and configure the element to use them.
+.CS
+vector X Y
+\&.g element configure line1 -xdata X -ydata Y
+.CE
+To set data points from C, you pass the values as arrays of doubles
+using the \fBBlt_ResetVector\fR call.  The vector is reset with the
+new data and at the next idle point (when Tk re-enters its event
+loop), the graph will be redrawn automatically.
+.CS
+#include <tcl.h>
+#include <blt.h>
+
+register int i;
+Blt_Vector *xVec, *yVec;
+double x[50], y[50];
+
+/* Get the BLT vectors "X" and "Y" (created above from Tcl) */
+if ((Blt_GetVector(interp, "X", &xVec) != TCL_OK) ||
+    (Blt_GetVector(interp, "Y", &yVec) != TCL_OK)) {
+    return TCL_ERROR;
+}
+
+for (i = 0; i < 50; i++) {
+    x[i] = i * 0.02;
+    y[i] = sin(x[i]);
+}	
+
+/* Put the data into BLT vectors */
+if ((Blt_ResetVector(xVec, x, 50, 50, TCL_VOLATILE) != TCL_OK) ||
+    (Blt_ResetVector(yVec, y, 50, 50, TCL_VOLATILE) != TCL_OK)) {
+   return TCL_ERROR;
+}
+.CE
+See the \fBvector\fR manual page for more details.
+.SH SPEED TIPS
+There may be cases where the graph needs to be drawn and updated as
+quickly as possible.  If drawing speed becomes a big
+problem, here are a few tips to speed up displays.
+.TP 2
+\(bu 
+Try to minimize the number of data points.  The more data points
+the looked at, the more work the graph must do.
+.TP 2
+\(bu 
+If your data is generated as floating point values, the time required
+to convert the data values to and from ASCII strings can be
+significant, especially when there any many data points.  You can
+avoid the redundant string-to-decimal conversions using the C API to
+BLT vectors.
+.TP 2
+\(bu
+Data elements without symbols are drawn faster than with symbols.
+Set the data element's \fB\-symbol\fR option to \f(CWnone\fR.  If you need to
+draw symbols, try using the simple symbols such as \f(CWsplus\fR and
+\f(CWscross\fR.
+.TP 2
+\(bu
+Don't stipple or dash the element.  Solid lines are much faster.
+.TP 2
+\(bu 
+If you update data elements frequently, try turning off the
+widget's \fB\-bufferelements\fR option.  When the graph is first
+displayed, it draws data elements into an internal pixmap.  The pixmap
+acts as a cache, so that when the graph needs to be redrawn again, and
+the data elements or coordinate axes haven't changed, the pixmap is
+simply copied to the screen.  This is especially useful when you are
+using markers to highlight points and regions on the graph.  But if
+the graph is updated frequently, changing either the element data or
+coordinate axes, the buffering becomes redundant.
+.SH LIMITATIONS
+Auto-scale routines do not use requested min/max limits as boundaries
+when the axis is logarithmically scaled.
+.PP
+The PostScript output generated for polygons with more than 1500
+points may exceed the limits of some printers (See PostScript Language
+Reference Manual, page 568).  The work-around is to break the polygon
+into separate pieces.
+.SH KEYWORDS
+graph, widget
diff --git a/doc/vector.n b/doc/vector.n
new file mode 100644
index 0000000..da7abf2
--- /dev/null
+++ b/doc/vector.n
@@ -0,0 +1,1130 @@
+'\"
+'\" Copyright 1991-1997 by Lucent Technologies, Inc.
+'\"
+'\" Permission to use, copy, modify, and distribute this software and its
+'\" documentation for any purpose and without fee is hereby granted, provided
+'\" that the above copyright notice appear in all copies and that both that the
+'\" copyright notice and warranty disclaimer appear in supporting documentation,
+'\" and that the names of Lucent Technologies any of their entities not be used
+'\" in advertising or publicity pertaining to distribution of the software
+'\" without specific, written prior permission.
+'\"
+'\" Lucent Technologies disclaims all warranties with regard to this software,
+'\" including all implied warranties of merchantability and fitness.  In no event
+'\" shall Lucent Technologies be liable for any special, indirect or
+'\" consequential damages or any damages whatsoever resulting from loss of use,
+'\" data or profits, whether in an action of contract, negligence or other
+'\" tortuous action, arising out of or in connection with the use or performance
+'\" of this software.  
+'\"
+'\" Vector command created by George Howlett.
+'\"
+.so man.macros
+.TH blt::vector n BLT_VERSION BLT "BLT Built-In Commands"
+.BS
+'\" Note:  do not modify the .SH NAME line immediately below!
+.SH NAME
+\fBvector\fR \-  Vector data type for Tcl
+.SH SYNOPSIS
+\fBblt::vector create \fIvecName \fR?\fIvecName\fR...? ?\fIswitches\fR? 
+.sp
+\fBblt::vector destroy \fIvecName \fR?\fIvecName\fR...?
+.sp
+\fBblt::vector expr \fIexpression\fR
+.sp
+\fBblt::vector names \fR?\fIpattern\fR...?
+.BE
+.SH DESCRIPTION
+The \fBvector\fR command creates an array of floating point
+values.  The vector's components can be manipulated in three ways:
+through a Tcl array variable, a Tcl command, or the C API.
+.SH INTRODUCTION
+A vector is an ordered set of real numbers.  The components of a
+vector are indexed by integers.
+.PP
+Vectors are common data structures for many applications.  For
+example, a graph may use two vectors to represent the X-Y
+coordinates of the data plotted.  The graph will automatically
+be redrawn when the vectors are updated or changed. By using vectors, 
+you can separate
+data analysis from the graph widget.  This makes it easier, for
+example, to add data transformations, such as splines.  It's possible
+to plot the same data to in multiple graphs, where each graph presents
+a different view or scale of the data.
+.PP
+You could try to use Tcl's associative arrays as vectors.  Tcl arrays
+are easy to use.  You can access individual elements randomly by
+specifying the index, or the set the entire array by providing a list
+of index and value pairs for each element.  The disadvantages of 
+associative arrays as vectors lie in the fact they are implemented as
+hash tables.
+.TP 2
+\(bu 
+There's no implied ordering to the associative arrays.  If you used
+vectors for plotting, you would want to insure the second component
+comes after the first, an so on.  This isn't possible since arrays
+are actually hash tables.  For example, you can't get a range of
+values between two indices.  Nor can you sort an array.
+.TP 2
+\(bu
+Arrays consume lots of memory when the number of elements becomes
+large (tens of thousands).  This is because each element's index and
+value are stored as strings in the hash table.
+.TP 2
+\(bu 
+The C programming interface is unwieldy.  Normally with vectors, you
+would like to view the Tcl array as you do a C array, as an array of
+floats or doubles.  But with hash tables, you must convert both the
+index and value to and from decimal strings, just to access
+an element in the array.  This makes it cumbersome to perform operations on
+the array as a whole.
+.PP
+The \fBvector\fR command tries to overcome these disadvantages while
+still retaining the ease of use of Tcl arrays.  The \fBvector\fR
+command creates both a new Tcl command and associate array which are
+linked to the vector components.  You can randomly access vector
+components though the elements of array.  Not have all indices are
+generated for the array, so printing the array (using the \fBparray\fR
+procedure) does not print out all the component values.  You can use
+the Tcl command to access the array as a whole.  You can copy, append,
+or sort vector using its command.  If you need greater performance, or
+customized behavior, you can write your own C code to manage vectors.
+.SH EXAMPLE
+You create vectors using the \fBvector\fR command and its \fBcreate\fR
+operation.
+.CS
+# Create a new vector. 
+blt::vector create y(50)
+.CE
+This creates a new vector named \f(CWy\fR.  It has fifty components, by
+default, initialized to \f(CW0.0\fR.  In addition, both a Tcl command
+and array variable, both named \f(CWy\fR, are created.  You can use
+either the command or variable to query or modify components of the
+vector.
+.CS
+# Set the first value. 
+set y(0) 9.25
+puts "y has [y length] components"
+.CE
+The array \f(CWy\fR can be used to read or set individual components of
+the vector.  Vector components are indexed from zero.  The array index
+must be a number less than the number of components.  For example,
+it's an error if you try to set the 51st element of \f(CWy\fR.
+.CS
+# This is an error. The vector only has 50 components.
+set y(50) 0.02
+.CE
+You can also specify a range of indices using a colon (:) to separate
+the first and last indices of the range.
+.CS
+# Set the first six components of y 
+set y(0:5) 25.2
+.CE
+If you don't include an index, then it will default to the first
+and/or last component of the vector.
+.CS
+# Print out all the components of y 
+puts "y = $y(:)"
+.CE
+There are special non-numeric indices.  The index \f(CWend\fR, specifies
+the last component of the vector.  It's an error to use this index if
+the vector is empty (length is zero).  The index \f(CW++end\fR can be
+used to extend the vector by one component and initialize it to a specific 
+value.  You can't read from the array using this index, though.
+.CS
+# Extend the vector by one component.
+set y(++end) 0.02
+.CE
+The other special indices are \f(CWmin\fR and \f(CWmax\fR.  They return the
+current smallest and largest components of the vector.  
+.CS
+# Print the bounds of the vector
+puts "min=$y(min) max=$y(max)"
+.CE
+To delete components from a vector, simply unset the corresponding
+array element. In the following example, the first component of
+\f(CWy\fR is deleted.  All the remaining components of \f(CWy\fR will be
+moved down by one index as the length of the vector is reduced by
+one.
+.CS
+# Delete the first component
+unset y(0)
+puts "new first element is $y(0)"
+.CE
+The vector's Tcl command can also be used to query or set the vector.
+.CS
+# Create and set the components of a new vector
+blt::vector create x
+x set { 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 }
+.CE
+Here we've created a vector \f(CWx\fR without a initial length specification.
+In this case, the length is zero.  The \fBset\fR operation resets the vector,
+extending it and setting values for each new component.  
+.PP
+There are several operations for vectors.  The \fBrange\fR operation
+lists the components of a vector between two indices.
+.CS
+# List the components 
+puts "x = [x range 0 end]"
+.CE
+You can search for a particular value using the \fBsearch\fR
+operation.  It returns a list of indices of the components with the
+same value.  If no component has the same value, it returns \f(CW""\fR.
+.CS
+# Find the index of the biggest component
+set indices [x search $x(max)]
+.CE
+Other operations copy, append, or sort vectors.  You can append
+vectors or new values onto an existing vector with the \fBappend\fR
+operation.
+.CS
+# Append assorted vectors and values to x
+x append x2 x3 { 2.3 4.5 } x4
+.CE
+The \fBsort\fR operation sorts the vector.  If any additional vectors
+are specified, they are rearranged in the same order as the vector.
+For example, you could use it to sort data points represented by x and
+y vectors.
+.CS
+# Sort the data points
+x sort y
+.CE
+The vector \f(CWx\fR is sorted while the components of \f(CWy\fR are 
+rearranged so that the original x,y coordinate pairs are retained.
+.PP
+The \fBexpr\fR operation lets you perform arithmetic on vectors.  
+The result is stored in the vector.
+.CS
+# Add the two vectors and a scalar
+x expr { x + y }
+x expr { x * 2 }
+.CE
+When a vector is modified, resized, or deleted, it may trigger
+call-backs to notify the clients of the vector.  For example, when a
+vector used in the \fBgraph\fR widget is updated, the vector
+automatically notifies the widget that it has changed.  The graph can
+then redrawn itself at the next idle point.  By default, the
+notification occurs when Tk is next idle.  This way you can modify the
+vector many times without incurring the penalty of the graph redrawing
+itself for each change.  You can change this behavior using the
+\fBnotify\fR operation.
+.CS
+# Make vector x notify after every change
+x notify always
+	...
+# Never notify
+x notify never
+	...
+# Force notification now
+x notify now
+.CE
+To delete a vector, use the \fBvector delete\fR command.  
+Both the vector and its corresponding Tcl command are destroyed.
+.CS
+# Remove vector x
+blt::vector destroy x
+.CE
+.SH SYNTAX
+Vectors are created using the \fBvector create\fR operation.  
+Th \fBcreate\fR operation can be invoked in one of three forms:
+.TP
+\fBblt::vector create \fIvecName\fR
+This creates a new vector \fIvecName\fR which initially has no components.
+.TP
+\fBblt::vector create \fIvecName\fR(\fIsize\fR)
+This second form creates a new vector which will contain \fIsize\fR
+number of components.  The components will be indexed starting from
+zero (0). The default value for the components is \f(CW0.0\fR.
+.TP
+\fBblt::vector create \fIvecName\fR(\fIfirst\fR:\fIlast\fR)
+The last form creates a new vector of indexed \fIfirst\fR through
+\fIlast\fR.  \fIFirst\fR and \fIlast\fR can be any integer value
+so long as \fIfirst\fR is less than \fIlast\fR.
+.PP
+Vector names must start with a letter and consist of letters, digits,
+or underscores.  
+.CS
+# Error: must start with letter
+blt::vector create 1abc
+.CE
+You can automatically generate vector names using the
+"\f(CW#auto\fR" vector name.  The \fBcreate\fR operation will generate a 
+unique vector name.
+.CS
+set vec [blt::vector create #auto]
+puts "$vec has [$vec length] components"
+.CE
+.SS VECTOR INDICES
+Vectors are indexed by integers.  You can access the individual vector
+components via its array variable or Tcl command.  The string
+representing the index can be an integer, a numeric expression, a
+range, or a special keyword.
+.PP
+The index must lie within the current range of the vector, otherwise
+an an error message is returned.  Normally the indices of a vector
+are start from 0.  But you can use the \fBoffset\fR operation to
+change a vector's indices on-the-fly.
+.CS
+puts $vecName(0)
+vecName offset -5
+puts $vecName(-5)
+.CE
+You can also use numeric expressions as indices.  The result
+of the expression must be an integer value.  
+.CS
+set n 21
+set vecName($n+3) 50.2
+.CE
+The following special non-numeric indices are available: \f(CWmin\fR, \f(CWmax\fR, \f(CWend\fR, and
+\f(CW++end\fR.  
+.CS
+puts "min = $vecName($min)"
+set vecName(end) -1.2
+.CE
+The indices \f(CWmin\fR and \f(CWmax\fR will return the minimum and maximum
+values of the vector.  The index \f(CWend\fR returns the value of the 
+last component in the vector.  The index \f(CW++end\fR is used to append
+new value onto the vector.  It automatically extends the vector by
+one component and sets its value.
+.CS
+# Append an new component to the end
+set vecName(++end) 3.2
+.CE
+A range of indices can be indicated by a colon (:).  
+.CS
+# Set the first six components to 1.0
+set vecName(0:5) 1.0
+.CE
+If no index is supplied the first or last component is assumed.
+.CS
+# Print the values of all the components
+puts $vecName(:)
+.CE
+.SH VECTOR OPERATIONS
+.TP
+\fBblt::vector create \fIvecName\fR?(\fIsize\fR)?... \fR?\fIswitches\fR? 
+The \fBcreate\fR operation creates a new vector \fIvecName\fR.  Both a
+Tcl command and array variable \fIvecName\fR are also created.  The
+name \fIvecName\fR must be unique, so another Tcl command or array
+variable can not already exist in that scope.  You can access the
+components of the vector using its variable.  If you change a value in
+the array, or unset an array element, the vector is updated to reflect
+the changes.  When the variable \fIvecName\fR is unset, the vector and
+its Tcl command are also destroyed.
+.sp
+The vector has optional switches that affect how the vector is created. They
+are as follows:
+.RS
+.TP
+\fB\-variable \fIvarName\fR
+Specifies the name of a Tcl variable to be mapped to the vector. If
+the variable already exists, it is first deleted, then recreated. 
+If \fIvarName\fR is the empty string, then no variable will be mapped.
+You can always map a variable back to the vector using the vector's 
+\fBvariable\fR operation.
+.TP
+\fB\-command \fIcmdName\fR
+Maps a Tcl command to the vector. The vector can be accessed using 
+\fIcmdName\fR and one of the vector instance operations.  
+A Tcl command by that name cannot already exist.
+If \fIcmdName\fR is the empty string, no command mapping
+will be made.
+.TP
+\fB\-watchunset \fIboolean\fR
+Indicates that the vector should automatically delete itself if
+the variable associated with the vector is unset.  By default,
+the vector will not be deleted.  This is different from previous
+releases.  Set \fIboolean\fR to "true" to get the old behavior.
+.RE
+.TP
+\fBblt::vector destroy \fIvecName\fR \fR?\fIvecName...\fR?
+Deletes one or more vectors.  Both the Tcl command and array variable
+are removed also.
+.TP
+\fBblt::vector expr \fIexpression\fR
+.RS
+All binary operators take vectors as operands (remember that numbers
+are treated as one-component vectors).  The exact action of binary
+operators depends upon the length of the second operand.  If the
+second operand has only one component, then each element of the first
+vector operand is computed by that value.  For example, the expression
+"x * 2" multiples all elements of the vector x by 2.  If the second
+operand has more than one component, both operands must be the same
+length.  Each pair of corresponding elements are computed.  So "x + y"
+adds the the first components of x and y together, the second, and so on.
+.sp
+The valid operators are listed below, grouped in decreasing order
+of precedence:
+.TP 20
+\fB\-\0\0!\fR
+Unary minus and logical NOT.  The unary minus flips the sign of each
+component in the vector.  The logical not operator returns a vector of
+whose values are 0.0 or 1.0.  For each non-zero component 1.0 is returned,
+0.0 otherwise.
+.TP 20
+\fB^\fR
+Exponentiation.  
+.TP 20
+\fB*\0\0/\0\0%\fR
+Multiply, divide, remainder.  
+.TP 20
+\fB+\0\0\-\fR
+Add and subtract.  
+.TP 20
+\fB<<\0\0>>\fR
+Left and right shift.  Circularly shifts the values of the vector 
+(not implemented yet).
+.TP 20
+\fB<\0\0>\0\0<=\0\0>=\fR
+Boolean less, greater, less than or equal, and greater than or equal.
+Each operator returns a vector of ones and zeros.  If the condition is true, 
+1.0 is the component value, 0.0 otherwise.
+.TP 20
+\fB==\0\0!=\fR
+Boolean equal and not equal.
+Each operator returns a vector of ones and zeros.  If the condition is true, 
+1.0 is the component value, 0.0 otherwise.
+.TP 20
+\fB|\fR
+Bit-wise OR.  (Not implemented).
+.TP 20
+\fB&&\fR
+Logical AND.  Produces a 1 result if both operands are non-zero, 0 otherwise.
+.TP 20
+\fB||\fR
+Logical OR.  Produces a 0 result if both operands are zero, 1 otherwise.
+.TP 20
+\fIx\fB?\fIy\fB:\fIz\fR
+If-then-else, as in C.  (Not implemented yet).
+.LP
+See the C manual for more details on the results produced by each
+operator.  All of the binary operators group left-to-right within the
+same precedence level.  
+.sp
+Several mathematical functions are supported for vectors.  Each of
+the following functions invokes the math library function of the same name;
+see the manual entries for the library functions for details on what
+they do.  The operation is applied to all elements of the vector
+returning the results. 
+.CS
+.ta 3c 6c 9c
+\fBacos\fR	\fBcos\fR	\fBhypot\fR	\fBsinh\fR 
+\fBasin\fR	\fBcosh\fR	\fBlog\fR	\fBsqrt\fR 
+\fBatan\fR	\fBexp\fR	\fBlog10\fR	\fBtan\fR  
+\fBceil\fR	\fBfloor\fR	\fBsin\fR	\fBtanh\fR 
+.CE
+Additional functions are:
+.TP 1i
+\fBabs\fR
+Returns the absolute value of each component.
+.TP 1i
+\fBrandom\fR
+Returns a vector of non-negative values uniformly distributed 
+between [0.0, 1.0) using \fIdrand48\fR.
+The seed comes from the internal clock of the machine or may be 
+set manual with the srandom function.
+.TP 1i
+\fBround\fR
+Rounds each component of the vector.
+.TP 1i
+\fBsrandom\fR
+Initializes the random number generator using \fIsrand48\fR.
+The high order 32-bits are set using the integral portion of the first 
+vector component. All other components are ignored.  The low order 16-bits 
+are set to an arbitrary value.
+.PP
+The following functions return a single value.
+.TP 1i
+\fBadev\fR 
+Returns the average deviation (defined as the sum of the absolute values 
+of the differences between component and the mean, divided by the length
+of the vector).
+.TP 1i
+\fBkurtosis\fR
+Returns the degree of peakedness (fourth moment) of the vector.
+.TP 1i
+\fBlength\fR
+Returns the number of components in the vector.
+.TP 1i
+\fBmax\fR
+Returns the vector's maximum value.
+.TP 1i
+\fBmean\fR
+Returns the mean value of the vector.
+.TP 1i
+\fBmedian\fR
+Returns the median of the vector.
+.TP 1i
+\fBmin\fR
+Returns the vector's minimum value.
+.TP 1i
+\fBq1\fR
+Returns the first quartile of the vector.
+.TP 1i
+\fBq3\fR
+Returns the third quartile of the vector.
+.TP 1i
+\fBprod\fR 
+Returns the product of the components.
+.TP 1i
+\fBsdev\fR 
+Returns the standard deviation (defined as the square root of the variance)
+of the vector.
+.TP 1i
+\fBskew\fR 
+Returns the skewness (or third moment) of the vector.  This characterizes
+the degree of asymmetry of the vector about the mean.
+.TP 1i
+\fBsum\fR 
+Returns the sum of the components.
+.TP 1i
+\fBvar\fR
+Returns the variance of the vector. The sum of the squared differences 
+between each component and the mean is computed.  The variance is 
+the sum divided by the length of the vector minus 1.
+.PP
+The last set returns a vector of the same length as the argument.
+.TP 1i
+\fBnorm\fR 
+Scales the values of the vector to lie in the range [0.0..1.0].
+.TP 1i
+\fBsort\fR
+Returns the vector components sorted in ascending order.
+.RE
+.TP
+\fBvector names \fR?\fIpattern\fR?
+.SH INSTANCE OPERATIONS
+You can also use the vector's Tcl command to query or modify it.  The
+general form is
+.DS
+\fIvecName \fIoperation\fR \fR?\fIarg\fR?...
+.DE
+Both \fIoperation\fR and its arguments determine the exact behavior of
+the command.  The operations available for vectors are listed below.
+.TP
+\fIvecName \fBappend\fR \fIitem\fR ?\fIitem\fR?...
+Appends the component values from \fIitem\fR to \fIvecName\fR.
+\fIItem\fR can be either the name of a vector or a list of numeric
+values.
+.TP
+\fIvecName \fBbinread\fR \fIchannel\fR ?\fIlength\fR? ?\fIswitches\fR? 
+Reads binary values from a Tcl channel. Values are either appended
+to the end of the vector or placed at a given index (using the
+\fB\-at\fR option), overwriting existing values.  Data is read until EOF
+is found on the channel or a specified number of values \fIlength\fR 
+are read (note that this is not necessarily the same as the number of 
+bytes). The following switches are supported:
+.RS
+.TP
+\fB\-swap\fR
+Swap bytes and words.  The default endian is the host machine.
+.TP
+\fB\-at \fIindex\fR
+New values will start at vector index \fIindex\fR.  This will
+overwrite any current values.
+.TP
+\fB\-format\fR \fIformat\fR
+Specifies the format of the data.  \fIFormat\fR can be one of the
+following: "i1", "i2", "i4", "i8", "u1, "u2", "u4", "u8", "r4",
+"r8", or "r16".  The number indicates the number of bytes
+required for each value.  The letter indicates the type: "i" for signed,
+"u" for unsigned, "r" or real.  The default format is "r16".
+.RE
+.TP
+\fIvecName \fBclear\fR 
+Clears the element indices from the array variable associated with
+\fIvecName\fR.  This doesn't affect the components of the vector.  By
+default, the number of entries in the Tcl array doesn't match the
+number of components in the vector.  This is because its too expensive
+to maintain decimal strings for both the index and value for each
+component.  Instead, the index and value are saved only when you read
+or write an element with a new index.  This command removes the index
+and value strings from the array.  This is useful when the vector is
+large.
+.TP
+\fIvecName \fBdelete\fR \fIindex\fR ?\fIindex\fR?...
+Deletes the \fIindex\fRth component from the vector \fIvecName\fR.
+\fIIndex\fR is the index of the element to be deleted.  This is the
+same as unsetting the array variable element \fIindex\fR.  The vector
+is compacted after all the indices have been deleted.
+.TP
+\fIvecName \fBdup\fR \fIdestName\fR 
+Copies \fIvecName\fR to \fIdestName\fR. \fIDestName\fR is the name of a
+destination vector.  If a vector \fIdestName\fR already exists, it is
+overwritten with the components of \fIvecName\fR.  Otherwise a 
+new vector is created.
+.TP
+\fIvecName \fBexpr\fR \fIexpression\fR
+Computes the expression and resets the values of the vector accordingly.
+Both scalar and vector math operations are allowed.  All values in
+expressions are either real numbers or names of vectors.  All numbers
+are treated as one component vectors.
+.TP
+\fIvecName \fBlength\fR ?\fInewSize\fR?
+Queries or resets the number of components in \fIvecName\fR.
+\fINewSize\fR is a number specifying the new size of the vector.  If
+\fInewSize\fR is smaller than the current size of \fIvecName\fR,
+\fIvecName\fR is truncated.  If \fInewSize\fR is greater, the vector
+is extended and the new components are initialized to \f(CW0.0\fR.  If
+no \fInewSize\fR argument is present, the current length of the vector
+is returned.
+.TP
+\fIvecName \fBmerge\fR \fIsrcName\fR ?\fIsrcName\fR?...
+Merges the named vectors into a single vector.  The resulting 
+vector is formed by merging the components of each source vector 
+one index at a time.
+.TP
+\fIvecName \fBnotify\fR \fIkeyword\fR
+Controls how vector clients are notified of changes to the vector.  
+The exact behavior is determined by \fIkeyword\fR.
+.RS
+.TP 0.75i
+\f(CWalways\fR 
+Indicates that clients are to be notified immediately whenever the
+vector is updated.
+.TP
+\f(CWnever\fR
+Indicates that no clients are to be notified.
+.TP
+\f(CWwhenidle\fR
+Indicates that clients are to be notified at the next idle point
+whenever the vector is updated.
+.TP
+\f(CWnow\fR
+If any client notifications is currently pending, they are notified
+immediately.
+.TP
+\f(CWcancel\fR
+Cancels pending notifications of clients using the vector.
+.TP
+\f(CWpending\fR
+Returns \f(CW1\fR if a client notification is pending, and \f(CW0\fR otherwise.
+.RE
+.TP
+\fIvecName \fBoffset\fR ?\fIvalue\fR?
+Shifts the indices of the vector by the amount specified by \fIvalue\fR.
+\fIValue\fR is an integer number.  If no \fIvalue\fR argument is 
+given, the current offset is returned.
+.TP
+\fIvecName \fBpopulate\fR \fIdestName\fR ?\fIdensity\fR?
+Creates a vector \fIdestName\fR which is a superset of \fIvecName\fR.
+\fIDestName\fR will include all the components of \fIvecName\fR, in
+addition the interval between each of the original components will
+contain a \fIdensity\fR number of new components, whose values are
+evenly distributed between the original components values.  This is
+useful for generating abscissas to be interpolated along a spline.
+.TP
+\fIvecName \fBrange\fR \fIfirstIndex\fR ?\fIlastIndex\fR?...
+Returns a list of numeric values representing the vector components
+between two indices. Both \fIfirstIndex\fR and \fIlastIndex\fR are 
+indices representing the range of components to be returned. If 
+\fIlastIndex\fR is less than \fIfirstIndex\fR, the components are
+listed in reverse order.
+.TP
+\fIvecName \fBsearch\fR \fIvalue\fR ?\fIvalue\fR?  
+Searches for a value or range of values among the components of
+\fIvecName\fR.  If one \fIvalue\fR argument is given, a list of
+indices of the components which equal \fIvalue\fR is returned.  If a
+second \fIvalue\fR is also provided, then the indices of all
+components which lie within the range of the two values are returned.
+If no components are found, then \f(CW""\fR is returned.
+.TP
+\fIvecName \fBset\fR \fIitem\fR
+Resets the components of the vector to \fIitem\fR. \fIItem\fR can
+be either a list of numeric expressions or another vector.
+.TP
+\fIvecName \fBseq\fR \fIstart\fR ?\fIfinish\fR? ?\fIstep\fR?
+Generates a sequence of values starting with the value \fIstart\fR.
+\fIFinish\fR indicates the terminating value of the sequence.  
+The vector is automatically resized to contain just the sequence.
+If three arguments are present, \fIstep\fR designates the interval.  
+.sp
+With only two arguments (no \fIfinish\fR argument), the sequence will
+continue until the vector is filled.  With one argument, the interval 
+defaults to 1.0.
+.TP
+\fIvecName \fBsort\fR ?\fB-reverse\fR? ?\fIargName\fR?...  
+Sorts the vector \fIvecName\fR in increasing order.  If the
+\fB-reverse\fR flag is present, the vector is sorted in decreasing
+order.  If other arguments \fIargName\fR are present, they are the
+names of vectors which will be rearranged in the same manner as
+\fIvecName\fR.  Each vector must be the same length as \fIvecName\fR.
+You could use this to sort the x vector of a graph, while still
+retaining the same x,y coordinate pairs in a y vector.
+.TP
+\fIvecName \fBvariable\fR \fIvarName\fR
+Maps a Tcl variable to the vector, creating another means for 
+accessing the vector.  The variable \fIvarName\fR can't already 
+exist. This overrides any current variable mapping the vector
+may have.
+.RE
+.SH C LANGUAGE API
+You can create, modify, and destroy vectors from C code, using 
+library routines.  
+You need to include the header file \f(CWblt.h\fR. It contains the
+definition of the structure \fBBlt_Vector\fR, which represents the
+vector.  It appears below.
+.CS
+\fRtypedef struct {
+    double *\fIvalueArr\fR; 
+    int \fInumValues\fR;    
+    int \fIarraySize\fR;    
+    double \fImin\fR, \fImax\fR;  
+} \fBBlt_Vector\fR;
+.CE
+The field \fIvalueArr\fR points to memory holding the vector
+components.  The components are stored in a double precision array,
+whose size size is represented by \fIarraySize\fR.  \fINumValues\fR is
+the length of vector.  The size of the array is always equal to or
+larger than the length of the vector.  \fIMin\fR and \fImax\fR are
+minimum and maximum component values.
+.SH LIBRARY ROUTINES
+The following routines are available from C to manage vectors.
+Vectors are identified by the vector name.
+.PP
+\fBBlt_CreateVector\fR 
+.RS .25i
+.TP 1i
+Synopsis:
+.CS 
+int \fBBlt_CreateVector\fR (\fIinterp\fR, \fIvecName\fR, \fIlength\fR, \fIvecPtrPtr\fR)
+.RS 1.25i
+Tcl_Interp *\fIinterp\fR;
+char *\fIvecName\fR;
+int \fIlength\fR;
+Blt_Vector **\fIvecPtrPtr\fR;
+.RE
+.CE
+.TP
+Description:
+Creates a new vector \fIvecName\fR\fR with a length of \fIlength\fR.
+\fBBlt_CreateVector\fR creates both a new Tcl command and array 
+variable \fIvecName\fR.  Neither a command nor variable named 
+\fIvecName\fR can already exist.  A pointer to the vector is 
+placed into \fIvecPtrPtr\fR.
+.TP
+Results:
+Returns \f(CWTCL_OK\fR if the vector is successfully created.  If
+\fIlength\fR is negative, a Tcl variable or command \fIvecName\fR
+already exists, or memory cannot be allocated for the vector, then
+\f(CWTCL_ERROR\fR is returned and \fIinterp->result\fR will contain an
+error message.
+.RE
+.sp
+.PP
+\fBBlt_DeleteVectorByName\fR 
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+int \fBBlt_DeleteVectorByName\fR (\fIinterp\fR, \fIvecName\fR)
+.RS 1.25i
+Tcl_Interp *\fIinterp\fR;
+char *\fIvecName\fR;
+.RE
+.CE
+.TP 1i
+Description:
+Removes the vector \fIvecName\fR.  \fIVecName\fR is the name of a vector
+which must already exist.  Both the Tcl command and array variable
+\fIvecName\fR are destroyed.  All clients of the vector will be notified
+immediately that the vector has been destroyed.
+.TP
+Results:
+Returns \f(CWTCL_OK\fR if the vector is successfully deleted.  If
+\fIvecName\fR is not the name a vector, then \f(CWTCL_ERROR\fR is returned
+and \fIinterp->result\fR will contain an error message.
+.RE
+.sp
+.PP
+\fBBlt_DeleteVector\fR 
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+int \fBBlt_DeleteVector\fR (\fIvecPtr\fR)
+.RS 1.25i
+Blt_Vector *\fIvecPtr\fR;
+.RE
+.CE
+.TP 1i
+Description:
+Removes the vector pointed to by \fIvecPtr\fR.  \fIVecPtr\fR is a
+pointer to a vector, typically set by \fBBlt_GetVector\fR or
+\fBBlt_CreateVector\fR.  Both the Tcl command and array variable of
+the vector are destroyed.  All clients of the vector will be notified
+immediately that the vector has been destroyed.
+.TP
+Results:
+Returns \f(CWTCL_OK\fR if the vector is successfully deleted.  If
+\fIvecName\fR is not the name a vector, then \f(CWTCL_ERROR\fR is returned
+and \fIinterp->result\fR will contain an error message.
+.RE
+.sp
+.PP
+\fBBlt_GetVector\fR 
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+int \fBBlt_GetVector\fR (\fIinterp\fR, \fIvecName\fR, \fIvecPtrPtr\fR)
+.RS 1.25i
+Tcl_Interp *\fIinterp\fR;
+char *\fIvecName\fR;
+Blt_Vector **\fIvecPtrPtr\fR;
+.RE
+.CE
+.TP 1i
+Description:
+Retrieves the vector \fIvecName\fR.  \fIVecName\fR is the name of a
+vector which must already exist.  \fIVecPtrPtr\fR will point be set to
+the address of the vector.
+.TP
+Results:
+Returns \f(CWTCL_OK\fR if the vector is successfully retrieved.  If
+\fIvecName\fR is not the name of a vector, then \f(CWTCL_ERROR\fR is
+returned and \fIinterp->result\fR will contain an error message.
+.RE
+.sp
+.PP
+\fBBlt_ResetVector\fR 
+.PP
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+int \fBBlt_ResetVector\fR (\fIvecPtr\fR, \fIdataArr\fR, 
+	\fInumValues\fR, \fIarraySize\fR, \fIfreeProc\fR)
+.RS 1.25i
+Blt_Vector *\fIvecPtr\fR;
+double *\fIdataArr\fR;
+int *\fInumValues\fR;
+int *\fIarraySize\fR;
+Tcl_FreeProc *\fIfreeProc\fR;
+.RE
+.CE
+.TP
+Description: 
+Resets the components of the vector pointed to by \fIvecPtr\fR.
+Calling \fBBlt_ResetVector\fR will trigger the vector to dispatch
+notifications to its clients. \fIDataArr\fR is the array of doubles
+which represents the vector data. \fINumValues\fR is the number of
+elements in the array. \fIArraySize\fR is the actual size of the array
+(the array may be bigger than the number of values stored in
+it). \fIFreeProc\fP indicates how the storage for the vector component
+array (\fIdataArr\fR) was allocated.  It is used to determine how to
+reallocate memory when the vector is resized or destroyed.  It must be
+\f(CWTCL_DYNAMIC\fR, \f(CWTCL_STATIC\fR, \f(CWTCL_VOLATILE\fR, or a pointer
+to a function to free the memory allocated for the vector array. If
+\fIfreeProc\fR is \f(CWTCL_VOLATILE\fR, it indicates that \fIdataArr\fR
+must be copied and saved.  If \fIfreeProc\fR is \f(CWTCL_DYNAMIC\fR, it
+indicates that \fIdataArr\fR was dynamically allocated and that Tcl
+should free \fIdataArr\fR if necessary.  \f(CWStatic\fR indicates that
+nothing should be done to release storage for \fIdataArr\fR.
+.TP
+Results:
+Returns \f(CWTCL_OK\fR if the vector is successfully resized.  If
+\fInewSize\fR is negative, a vector \fIvecName\fR does not exist, or
+memory cannot be allocated for the vector, then \f(CWTCL_ERROR\fR is
+returned and \fIinterp->result\fR will contain an error message.
+.RE
+.sp
+.PP
+\fBBlt_ResizeVector\fR 
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+int \fBBlt_ResizeVector\fR (\fIvecPtr\fR, \fInewSize\fR)
+.RS 1.25i
+Blt_Vector *\fIvecPtr\fR;
+int \fInewSize\fR;
+.RE
+.CE
+.TP
+Description:
+Resets the length of the vector pointed to by \fIvecPtr\fR to
+\fInewSize\fR.  If \fInewSize\fR is smaller than the current size of
+the vector, it is truncated.  If \fInewSize\fR is greater, the vector
+is extended and the new components are initialized to \f(CW0.0\fR.
+Calling \fBBlt_ResetVector\fR will trigger the vector to dispatch
+notifications.
+.TP
+Results:
+Returns \f(CWTCL_OK\fR if the vector is successfully resized.  If
+\fInewSize\fR is negative or memory can not be allocated for the vector, 
+then \f(CWTCL_ERROR\fR is returned and \fIinterp->result\fR will contain 
+an error message.
+.sp
+.PP
+\fBBlt_VectorExists\fR 
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+int \fBBlt_VectorExists\fR (\fIinterp\fR, \fIvecName\fR)
+.RS 1.25i
+Tcl_Interp *\fIinterp\fR;
+char *\fIvecName\fR;
+.RE
+.CE
+.TP
+Description:
+Indicates if a vector named \fIvecName\fR exists in \fIinterp\fR.
+.TP
+Results:
+Returns \f(CW1\fR if a vector \fIvecName\fR exists and \f(CW0\fR otherwise.
+.RE
+.sp
+.PP
+If your application needs to be notified when a vector changes, it can
+allocate a unique \fIclient identifier\fR for itself.  Using this
+identifier, you can then register a call-back to be made whenever the
+vector is updated or destroyed.  By default, the call-backs are made at
+the next idle point.  This can be changed to occur at the time the
+vector is modified.  An application can allocate more than one
+identifier for any vector.  When the client application is done with
+the vector, it should free the identifier.
+.PP
+The call-back routine must of the following type.
+.CS
+.RS
+.sp
+typedef void (\fBBlt_VectorChangedProc\fR) (Tcl_Interp *\fIinterp\fR, 
+.RS .25i
+ClientData \fIclientData\fR, Blt_VectorNotify \fInotify\fR);
+.RE
+.sp
+.RE
+.CE
+.fi
+\fIClientData\fR is passed to this routine whenever it is called.  You
+can use this to pass information to the call-back.  The \fInotify\fR 
+argument indicates whether the vector has been updated of destroyed. It
+is an enumerated type.
+.CS
+.RS
+.sp
+typedef enum {
+    \f(CWBLT_VECTOR_NOTIFY_UPDATE\fR=1,
+    \f(CWBLT_VECTOR_NOTIFY_DESTROY\fR=2
+} \fBBlt_VectorNotify\fR;
+.sp
+.RE
+.CE
+.PP
+\fBBlt_AllocVectorId\fR
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+Blt_VectorId \fBBlt_AllocVectorId\fR (\fIinterp\fR, \fIvecName\fR)
+.RS 1.25i
+Tcl_Interp *\fIinterp\fR;
+char *\fIvecName\fR;
+.RE
+.CE
+.TP
+Description:
+Allocates an client identifier for with the vector \fIvecName\fR.
+This identifier can be used to specify a call-back which is triggered
+when the vector is updated or destroyed.
+.TP
+Results:
+Returns a client identifier if successful.  If \fIvecName\fR is not
+the name of a vector, then \f(CWNULL\fR is returned and
+\fIinterp->result\fR will contain an error message.
+.RE
+.sp
+.PP
+\fBBlt_GetVectorById\fR 
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+int \fBBlt_GetVector\fR (\fIinterp\fR, \fIclientId\fR, \fIvecPtrPtr\fR)
+.RS 1.25i
+Tcl_Interp *\fIinterp\fR;
+Blt_VectorId \fIclientId\fR;
+Blt_Vector **\fIvecPtrPtr\fR;
+.RE
+.CE
+.TP 1i
+Description:
+Retrieves the vector used by \fIclientId\fR.  \fIClientId\fR is a valid
+vector client identifier allocated by \fBBlt_AllocVectorId\fR.
+\fIVecPtrPtr\fR will point be set to the address of the vector.
+.TP
+Results:
+Returns \f(CWTCL_OK\fR if the vector is successfully retrieved.  
+.RE
+.sp
+.PP
+\fBBlt_SetVectorChangedProc\fR
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+void \fBBlt_SetVectorChangedProc\fR (\fIclientId\fR, \fIproc\fR, \fIclientData\fR);
+.RS 1.25i
+Blt_VectorId \fIclientId\fR;
+Blt_VectorChangedProc *\fIproc\fR;
+ClientData *\fIclientData\fR;
+.RE
+.CE
+.TP
+Description: 
+Specifies a call-back routine to be called whenever the vector
+associated with \fIclientId\fR is updated or deleted.  \fIProc\fR is a
+pointer to call-back routine and must be of the type
+\fBBlt_VectorChangedProc\fR.  \fIClientData\fR is a one-word value to
+be passed to the routine when it is invoked. If \fIproc\fR is
+\f(CWNULL\fR, then the client is not notified.
+.TP
+Results:
+The designated call-back procedure will be invoked when the vector is 
+updated or destroyed.
+.RE
+.sp
+.PP
+\fBBlt_FreeVectorId\fR
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+void \fBBlt_FreeVectorId\fR (\fIclientId\fR);
+.RS 1.25i
+Blt_VectorId \fIclientId\fR;
+.RE
+.CE
+.TP
+Description: 
+Frees the client identifier.  Memory allocated for the identifier 
+is released.  The client will no longer be notified when the
+vector is modified.
+.TP
+Results:
+The designated call-back procedure will be no longer be invoked when
+the vector is updated or destroyed.
+.RE
+.sp
+.PP
+\fBBlt_NameOfVectorId\fR
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+char *\fBBlt_NameOfVectorId\fR (\fIclientId\fR);
+.RS 1.25i
+Blt_VectorId \fIclientId\fR;
+.RE
+.CE
+.TP
+Description: 
+Retrieves the name of the vector associated with the client identifier
+\fIclientId\fR.  
+.TP
+Results:
+Returns the name of the vector associated with \fIclientId\fR.  If
+\fIclientId\fR is not an identifier or the vector has been destroyed, 
+\f(CWNULL\fR is returned.
+.RE
+.sp
+.PP
+\fBBlt_InstallIndexProc\fR
+.RS .25i
+.TP 1i
+Synopsis:
+.CS
+void \fBBlt_InstallIndexProc\fR (\fIindexName\fR, \fIprocPtr\fR)
+.RS 1.25i
+char *\fIindexName\fR;
+Blt_VectorIndexProc *\fIprocPtr\fR;
+.RE
+.CE
+.TP
+Description: 
+Registers a function to be called to retrieved the index \fIindexName\fR
+from the vector's array variable.  
+.sp
+typedef double Blt_VectorIndexProc(Vector *vecPtr);
+.sp
+The function will be passed a pointer to the vector.  The function must
+return a double representing the value at the index.
+.TP
+Results:
+The new index is installed into the vector.
+.RE
+.RE
+.SH C API EXAMPLE
+The following example opens a file of binary data and stores it in an
+array of doubles. The array size is computed from the size of the
+file. If the vector "data" exists, calling \fBBlt_VectorExists\fR,
+\fBBlt_GetVector\fR is called to get the pointer to the vector.
+Otherwise the routine \fBBlt_CreateVector\fR is called to create a new
+vector and returns a pointer to it. Just like the Tcl interface, both
+a new Tcl command and array variable are created when a new vector is
+created. It doesn't make any difference what the initial size of the
+vector is since it will be reset shortly. The vector is updated when
+\fBlt_ResetVector\fR is called.  Blt_ResetVector makes the changes
+visible to the Tcl interface and other vector clients (such as a graph
+widget).
+.sp
+.CS
+#include <tcl.h>
+#include <blt.h>				
+...
+Blt_Vector *vecPtr;
+double *newArr;
+FILE *f;
+struct stat statBuf;
+int numBytes, numValues;
+
+f = fopen("binary.dat", "r");
+fstat(fileno(f), &statBuf);
+numBytes = (int)statBuf.st_size;
+
+/* Allocate an array big enough to hold all the data */
+newArr = (double *)malloc(numBytes);
+numValues = numBytes / sizeof(double);
+fread((void *)newArr, numValues, sizeof(double), f);
+fclose(f);
+
+if (Blt_VectorExists(interp, "data"))  {
+    if (Blt_GetVector(interp, "data", &vecPtr) != TCL_OK) {
+	return TCL_ERROR;
+    }
+} else {
+   if (Blt_CreateVector(interp, "data", 0, &vecPtr) != TCL_OK) {
+	return TCL_ERROR;
+   }
+}
+/* 
+ * Reset the vector. Clients will be notified when Tk is idle. 
+ * TCL_DYNAMIC tells the vector to free the memory allocated 
+ * if it needs to reallocate or destroy the vector.
+ */
+if (Blt_ResetVector(vecPtr, newArr, numValues, numValues, 
+	TCL_DYNAMIC) != TCL_OK) {
+    return TCL_ERROR;
+}
+.CE
+.SH "INCOMPATIBILITIES"
+In previous versions, if the array variable isn't global 
+(i.e. local to a Tcl procedure), the vector is automatically 
+destroyed when the procedure returns.
+.CS
+proc doit {} {
+    # Temporary vector x
+    vector x(10)
+    set x(9) 2.0
+      ...
+}
+.CE
+.PP
+This has changed.  Variables are not automatically destroyed when
+their variable is unset.  You can restore the old behavior by
+setting the "-watchunset" switch.
+.CE
+.SH KEYWORDS
+vector, graph, widget