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<H2>SYNOPSIS</H2><PRE>
<B>barchart</B> <I>pathName</I> ?<I>option</I> <I>value</I>?...
</PRE>
<H2>DESCRIPTION</H2><PRE>
The <B>barchart</B> 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.
</PRE>
<H2>INTRODUCTION</H2><PRE>
The <B>barchart</B> 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 <I>plotting</I> <I>area</I>. 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 dis-
played in top margin.
A <B>barchart</B> widget has several configurable components: coordinate axes,
data elements, legend, grid, cross hairs, pens, postscript, and annota-
tion markers. Each component can be queried or modified.
axis Up to four coordinate axes (two X-coordinate and two Y-coor-
dinate 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.
crosshairs
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.
element An element represents a set of data to be plotted. It con-
tains 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-coordi-
nate) of the data point. The appearance of the bar, such as
its color, stipple, or relief is configurable.
A special case exists when two or more data points have the
same abscissa (X-coordinate). By default, the bars are over-
layed, one on top of the other. The bars are drawn in the
order of the element display list. But you can also config-
ure 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
pen 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 <B>-weight</B> and <B>-style</B> options).
postscript
The widget can generate encapsulated PostScript output. This
component has several options to configure how the PostScript
is generated.
</PRE>
<H2>SYNTAX</H2><PRE>
<B>barchart</B> <I>pathName</I> ?<I>option</I> <I>value</I>?... The <B>barchart</B> command creates a new
window <I>pathName</I> and makes it into a <B>barchart</B> widget. At the time this
command is invoked, there must not exist a window named <I>pathName</I>, but
<I>pathName</I>'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 <B>configure</B> operation below
for the exact details about what <I>option</I> and <I>value</I> pairs are valid.
If successful, <B>barchart</B> 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 gen-
eral form is: <I>pathName</I> <I>operation</I> ?<I>arg</I>?... Both <I>operation</I> and its argu-
ments determine the exact behavior of the command. The operations
available for the graph are described in the <B>BARCHART</B> <B>OPERATIONS</B> sec-
tion.
The command can also be used to access components of the graph. <I>path-</I>
<I>Name</I> <I>component</I> <I>operation</I> ?<I>arg</I>?... The operation, now located after the
name of the component, is the function to be performed on that compo-
nent. Each component has its own set of operations that manipulate that
component. They will be described below in their own sections.
</PRE>
<H2>EXAMPLE</H2><PRE>
The <B>barchart</B> command creates a new bar chart. # Create a new bar
chart. Plotting area is black. barchart .b -plotbackground black A
new Tcl command .b 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 <B>configure</B> operation. #
Change the title. .b configure -title "My Plot" To add data elements,
you use the command and the <B>element</B> component. # 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 } The element's X-Y coordinates are
specified using lists of numbers. Alternately, BLT vectors could be
used to hold the X-Y coordinates. # 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 yVec-
tor The advantage of using vectors is that when you modify one, the
sure we change the bar width too. .b configure -barwidth 0.2 The
height of each bar is proportional to the ordinate (Y-coordinate) of
the data point.
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 <B>-barmode</B> configuration option), the
bars are stacked, each bar above the previous. # Display the elements
as stacked. .b configure -barmode stacked 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. # Display the ele-
ments side-by-side. .b configure -barmode aligned By default, the ele-
ment's label in the legend will be also e1. You can change the label,
or specify no legend entry, again using the element's <B>configure</B> opera-
tion. # Don't display "e1" in the legend. .b element configure e1
-label "" You can configure more than just the element's label. An
element has many attributes such as stipple, foreground and background
colors, relief, etc. .b element configure e1 -fg red -bg pink \
-stipple gray50 Four coordinate axes are automatically created: x,
x2, y, and y2. And by default, elements are mapped onto the axes x and
y. This can be changed with the <B>-mapx</B> and <B>-mapy</B> options. # Map "e1"
on the alternate y axis "y2". .b element configure e1 -mapy y2 Axes
can be configured in many ways too. For example, you change the scale
of the Y-axis from linear to log using the <B>axis</B> component. # Y-axis is
log scale. .b axis configure y -logscale yes 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 <B>-min</B> and <B>-max</B> configuration
options. .b axis configure x -min 1.0 -max 1.5 .b axis configure y
-min 12.0 -max 55.15 To zoom interactively, you link the<B>axis</B> <B>configure</B>
operations with some user interaction (such as pressing the mouse but-
ton), using the <B>bind</B> command. To convert between screen and graph
coordinates, use the <B>invtransform</B> operation. # 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] } By default,
the limits of the axis are determined from data values. To reset back
to the default limits, set the <B>-min</B> and <B>-max</B> options to the empty
value. # Reset the axes to autoscale again. .b axis configure x -min
{} -max {} .b axis configure y -min {} -max {} By default, the legend
is drawn in the right margin. You can change this or any legend con-
figuration options using the <B>legend</B> component. # Configure the legend
font, color, and relief .b legend configure -position left -relief
raised \ -font fixed -fg blue To prevent the legend from being
displayed, turn on the <B>-hide</B> option. # Don't display the legend. .b
legend configure -hide yes The <B>barchart</B> 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
chart into file "file.ps" .b postscript output file.ps -maxpect yes
-decorations no This generates a file file.ps containing the encapsu-
lated PostScript of the graph. The option <B>-maxpect</B> says to scale the
plot to the size of the page. Turning off the <B>-decorations</B> 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).
</PRE>
<H2>SYNTAX</H2><PRE>
<B>barchart</B> <I>pathName</I> ?<I>option</I> <I>value</I>?... The <B>barchart</B> command creates a new
window <I>pathName</I> and makes it into a barchart widget. At the time this
command is invoked, there must not exist a window named <I>pathName</I>, but
<I>pathName</I>'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 <B>configure</B> operation
below for the exact details as to what <I>option</I> and <I>value</I> pairs are
valid.
If successful, <B>barchart</B> returns <I>pathName</I>. It also creates a new Tcl
command <I>pathName</I>. This command may be used to invoke various opera-
tions to query or modify the bar chart. It has the general form: <I>path-</I>
<I>Name</I> <I>operation</I> ?<I>arg</I>?... Both <I>operation</I> and its arguments determine the
exact behavior of the command. The operations available for the bar
chart are described in the following section.
</PRE>
<H2>BARCHART OPERATIONS</H2><PRE>
<I>pathName</I> <B>bar</B> <I>elemName</I> ?<I>option</I> <I>value</I>?...
Creates a new barchart element <I>elemName</I>. It's an error if an
element <I>elemName</I> already exists. See the manual for <B>barchart</B>
for details about what <I>option</I> and <I>value</I> pairs are valid.
<I>pathName</I> <B>cget</B> <I>option</I>
Returns the current value of the configuration option given by
<I>option</I>. <I>Option</I> may be any option described below for the <B>con-</B>
<B>figure</B> operation.
<I>pathName</I> <B>configure</B> ?<I>option</I> <I>value</I>?...
Queries or modifies the configuration options of the graph. If
<I>option</I> isn't specified, a list describing the current options
for <I>pathName</I> is returned. If <I>option</I> is specified, but not
<I>value</I>, then a list describing <I>option</I> is returned. If one or
more <I>option</I> and <I>value</I> pairs are specified, then for each pair,
the option <I>option</I> is set to <I>value</I>. The following options are
valid.
<B>-background</B> <I>color</I>
Sets the background color. This includes the margins and
legend, but not the plotting area.
<B>-barmode</B> <I>mode</I>
Indicates how related bar elements will be drawn.
Related elements have data points with the same abscissas
(X-coordinates). <I>Mode</I> indicates how those segments should
<B>-barwidth</B> <I>value</I>
Specifies the width of the bars. This value can be over-
rided by the individual elements using their <B>-barwidth</B>
configuration option. <I>Value</I> is the width in terms of
graph-coordinates. The default width is 1.0.
<B>-borderwidth</B> <I>pixels</I>
Sets the width of the 3-D border around the outside edge
of the widget. The <B>-relief</B> option determines if the bor-
der is to be drawn. The default is 2.
<B>-bottommargin</B> <I>pixels</I>
Specifies the size of the margin below the X-coordinate
axis. If <I>pixels</I> is 0, the size of the margin is selected
automatically. The default is 0.
<B>-bufferelements</B> <I>boolean</I>
Indicates whether an internal pixmap to buffer the dis-
play of data elements should be used. If <I>boolean</I> 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 <B>SPEED</B>
<B>TIPS</B> section. The default is 1.
<B>-cursor</B> <I>cursor</I>
Specifies the widget's cursor. The default cursor is
crosshair.
<B>-font</B> <I>fontName</I>
Specifies the font of the graph title. The default is
*-Helvetica-Bold-R-Normal-*-18-180-*.
<B>-halo</B> <I>pixels</I>
Specifies a maximum distance to consider when searching
for the closest data point (see the element's <B>closest</B>
operation below). Data points further than <I>pixels</I> away
are ignored. The default is 0.5i.
<B>-height</B> <I>pixels</I>
Specifies the requested height of widget. The default is
4i.
<B>-invertxy</B> <I>boolean</I>
Indicates whether the placement X-axis and Y-axis should
be inverted. If <I>boolean</I> is true, the X and Y axes are
swapped. The default is 0.
<B>-justify</B> <I>justify</I>
Specifies how the title should be justified. This mat-
ters only when the title contains more than one line of
area. The <B>-plotrelief</B> option determines if a border is
drawn. The default is 2.
<B>-plotpadx</B> <I>pad</I>
Sets the amount of padding to be added to the left and
right sides of the plotting area. <I>Pad</I> can be a list of
one or two screen distances. If <I>pad</I> 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 <I>pad</I>
is just one distance, both the left and right sides are
padded evenly. The default is 8.
<B>-plotpady</B> <I>pad</I>
Sets the amount of padding to be added to the top and
bottom of the plotting area. <I>Pad</I> can be a list of one or
two screen distances. If <I>pad</I> has two elements, the top
of the plotting area is padded by the first distance and
the bottom by the second. If <I>pad</I> is just one distance,
both the top and bottom are padded evenly. The default
is 8.
<B>-plotrelief</B> <I>relief</I>
Specifies the 3-D effect for the plotting area. <I>Relief</I>
specifies how the interior of the plotting area should
appear relative to rest of the graph; for example, raised
means the plot should appear to protrude from the graph,
relative to the surface of the graph. The default is
sunken.
<B>-relief</B> <I>relief</I>
Specifies the 3-D effect for the barchart widget. <I>Relief</I>
specifies how the graph should appear relative to widget
it is packed into; for example, raised means the graph
should appear to protrude. The default is flat.
<B>-rightmargin</B> <I>pixels</I>
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 <I>pixels</I> is than 1, the margin
size is selected automatically.
<B>-takefocus</B> <I>focus</I>
Provides information used when moving the focus from win-
dow to window via keyboard traversal (e.g., Tab and
Shift-Tab). If <I>focus</I> is 0, this means that this window
should be skipped entirely during keyboard traversal. 1
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 "".
<B>-tile</B> <I>image</I>
<B>-width</B> <I>pixels</I>
Specifies the requested width of the widget. The default
is 5i.
<I>pathName</I> <B>crosshairs</B> <I>operation</I> ?<I>arg</I>?
See the <B>CROSSHAIRS</B> <B>COMPONENT</B> section.
<I>pathName</I> <B>element</B> <I>operation</I> ?<I>arg</I>?...
See the <B>ELEMENT</B> <B>COMPONENTS</B> section.
<I>pathName</I> <B>extents</B> <I>item</I>
Returns the size of a particular item in the graph. <I>Item</I> must
be either leftmargin, rightmargin, topmargin, bottommargin,
plotwidth, or plotheight.
<I>pathName</I> <B>grid</B> <I>operation</I> ?<I>arg</I>?...
See the <B>GRID</B> <B>COMPONENT</B> section.
<I>pathName</I> <B>invtransform</B> <I>winX</I> <I>winY</I>
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-coordi-
nates.
<I>pathName</I> <B>inside</B> <I>x</I> <I>y</I>
Returns 1 is the designated screen-coordinate (<I>x</I> and <I>y</I>) is
inside the plotting area and 0 otherwise.
<I>pathName</I> <B>legend</B> <I>operation</I> ?<I>arg</I>?...
See the <B>LEGEND</B> <B>COMPONENT</B> section.
<I>pathName</I> <B>line</B> <B>operation</B> <B>arg</B>...
The operation is the same as <B>element</B>.
<I>pathName</I> <B>marker</B> <I>operation</I> ?<I>arg</I>?...
See the <B>MARKER</B> <B>COMPONENTS</B> section.
<I>pathName</I> <B>metafile</B> ?<I>fileName</I>?
<I>This</I> <I>operation</I> <I>is</I> <I>for</I> <I>Window</I> <I>platforms</I> <I>only</I>. Creates a Windows
enhanced metafile of the barchart. If present, <I>fileName</I> is the
file name of the new metafile. Otherwise, the metafile is auto-
matically added to the clipboard.
<I>pathName</I> <B>postscript</B> <I>operation</I> ?<I>arg</I>?...
See the <B>POSTSCRIPT</B> <B>COMPONENT</B> section.
<I>pathName</I> <B>snap</B> <I>photoName</I>
Takes a snapshot of the graph and stores the contents in the
photo image <I>photoName</I>. <I>PhotoName</I> is the name of a Tk photo
image that must already exist.
<I>pathName</I> <B>transform</B> <I>x</I> <I>y</I>
A graph is composed of several components: coordinate axes, data ele-
ments, 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.
<B>AXIS</B> <B>COMPONENTS</B>
Four coordinate axes are automatically created: two X-coordinate axes
(x and x2) and two Y-coordinate axes (y, and y2). By default, the axis
x is located in the bottom margin, y in the left margin, x2 in the top
margin, and y2 in the right margin.
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.
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 plot-
ted. By default, the minimum and maximum limits are determined from
the data, but you can reset either limit.
You can create and use several axes. To create an axis, invoke the axis
component and its create operation. # Create a new axis called "tem-
perature" .b axis create temperature 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. # Now map the tempera-
ture data to this axis. .b element create "temp" -xdata $x -ydata
$tempData \
-mapy temperature 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 x and y are drawn in the bot-
tom and left margins. The axes x2 and y2 are drawn in top and right
margins. Only x and y are shown by default. Note that the axes can
have different scales.
To display a different axis, you invoke one of the following compo-
nents: <B>xaxis</B>, <B>yaxis</B>, <B>x2axis</B>, and <B>y2axis</B>. The <B>use</B> operation designates
the axis to be drawn in the corresponding margin: <B>xaxis</B> in the bottom,
<B>yaxis</B> in the left, <B>x2axis</B> in the top, and <B>y2axis</B> in the right. # Dis-
play the axis temperature in the left margin. .b yaxis use temperature
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.
<B>-autorange</B> <I>range</I>
Sets the range of values for the axis to <I>range</I>. The axis
limits are automatically reset to display the most recent
data points in this range. If <I>range</I> is 0.0, the range is
determined from the limits of the data. If <B>-min</B> or <B>-max</B>
are specified, they override this option. The default is
0.0.
<B>-color</B> <I>color</I>
Sets the color of the axis and tick labels. The default
is black.
<B>-command</B> <I>prefix</I>
Specifies a Tcl command to be invoked when formatting the
axis tick labels. <I>Prefix</I> 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 "" is returned, no label will appear next to
the tick. You can get the standard tick labels again by
setting <I>prefix</I> to "". The default is "".
Please note that this procedure is invoked while the bar
chart is redrawn. You may query the widget's configura-
tion options. But do not reset options, because this can
have unexpected results.
<B>-descending</B> <I>boolean</I>
Indicates whether the values along the axis are monotoni-
cally increasing or decreasing. If <I>boolean</I> is true, the
axis values will be decreasing. The default is 0.
<B>-hide</B> <I>boolean</I>
Indicates whether the axis is displayed.
<B>-justify</B> <I>justify</I>
Specifies how the axis title should be justified. This
matters only when the axis title contains more than one
line of text. <I>Justify</I> must be left, right, or center.
The default is center.
<B>-limits</B> <I>formatStr</I>
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. <I>FormatStr</I> is a list of one or two format descrip-
tions. 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 "" is given as
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
<I>boolean</I> is true, the axis range is "loose". The default
is 0.
<B>-majorticks</B> <I>majorList</I>
Specifies where to display major axis ticks. You can use
this option to display ticks at non-uniform intervals.
<I>MajorList</I> is a list of axis coordinates designating the
location of major ticks. No minor ticks are drawn. If
<I>majorList</I> is "", major ticks will be automatically com-
puted. The default is "".
<B>-max</B> <I>value</I>
Sets the maximum limit of <I>axisName</I>. Any data point
greater than <I>value</I> is not displayed. If <I>value</I> is "", the
maximum limit is calculated using the largest data value.
The default is "".
<B>-min</B> <I>value</I>
Sets the minimum limit of <I>axisName</I>. Any data point less
than <I>value</I> is not displayed. If <I>value</I> is "", the minimum
limit is calculated using the smallest data value. The
default is "".
<B>-minorticks</B> <I>minorList</I>
Specifies where to display minor axis ticks. You can use
this option to display minor ticks at non-uniform inter-
vals. <I>MinorList</I> 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 <B>-majortick</B> option is also
set. If <I>minorList</I> is "", minor ticks will be automati-
cally computed. The default is "".
<B>-rotate</B> <I>theta</I>
Specifies the how many degrees to rotate the axis tick
labels. <I>Theta</I> is a real value representing the number of
degrees to rotate the tick labels. The default is 0.0
degrees.
<B>-shiftby</B> <I>value</I>
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 <I>value</I>.
You can use this option to prevent the axis limits from
being recomputed at each new time point. If <I>value</I> is 0.0,
then no automatic shifting is down. The default is 0.0.
<B>-showticks</B> <I>boolean</I>
Indicates whether axis ticks should be drawn. If <I>boolean</I>
is true, ticks are drawn. If false, only the axis line
<B>-tickfont</B> <I>fontName</I>
Specifies the font for axis tick labels. The default is
*-Courier-Bold-R-Normal-*-100-*.
<B>-ticklength</B> <I>pixels</I>
Sets the length of major and minor ticks (minor ticks are
half the length of major ticks). If <I>pixels</I> is less than
zero, the axis will be inverted with ticks drawn pointing
towards the plot. The default is 0.1i.
<B>-title</B> <I>text</I>
Sets the title of the axis. If <I>text</I> is "", no axis title
will be displayed.
<B>-titlecolor</B> <I>color</I>
Sets the color of the axis title. The default is black.
<B>-titlefont</B> <I>fontName</I>
Specifies the font for axis title. The default is *-Hel-
vetica-Bold-R-Normal-*-14-140-*.
Axis configuration options may be also be set by the <B>option</B> com-
mand. The resource class is Axis. The resource names are the
names of the axes (such as x or x2). option add *Bar-
chart.Axis.Color blue option add *Barchart.x.LogScale true
option add *Barchart.x2.LogScale false
<I>pathName</I> <B>axis</B> <B>create</B> <I>axisName</I> ?<I>option</I> <I>value</I>?...
Creates a new axis by the name <I>axisName</I>. No axis by the same
name can already exist. <I>Option</I> and <I>value</I> are described in above
in the axis <B>configure</B> operation.
<I>pathName</I> <B>axis</B> <B>delete</B> ?<I>axisName</I>?...
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 ele-
ments.
<I>pathName</I> <B>axis</B> <B>invtransform</B> <I>axisName</I> <I>value</I>
Performs the inverse transformation, changing the screen-coordi-
nate <I>value</I> to a graph-coordinate, mapping the value mapped to
<I>axisName</I>. Returns the graph-coordinate.
<I>pathName</I> <B>axis</B> <B>limits</B> <I>axisName</I>
Returns a list of the minimum and maximum limits for <I>axisName</I>.
The order of the list is min max.
<I>pathName</I> <B>axis</B> <B>names</B> ?<I>pattern</I>?...
Returns a list of axes matching zero or more patterns. If no
<I>pattern</I> argument is give, the names of all axes are returned.
<I>pathName</I> <B>axis</B> <B>transform</B> <I>axisName</I> <I>value</I>
Transforms the coordinate <I>value</I> to a screen-coordinate by map-
right Y-axis.
They implicitly control the axis that is currently using to that loca-
tion. By default, <B>xaxis</B> uses the x axis, <B>yaxis</B> uses y, <B>x2axis</B> uses x2,
and <B>y2axis</B> uses y2. These components can be more convenient to use
than always determining what axes are current being displayed by the
graph.
The following operations are available for axes. They mirror exactly
the operations of the <B>axis</B> component. The <I>axis</I> argument must be <B>xaxis</B>,
<B>x2axis</B>, <B>yaxis</B>, or <B>y2axis</B>.
<I>pathName</I> <I>axis</I> <B>cget</B> <I>option</I>
<I>pathName</I> <I>axis</I> <B>configure</B> ?<I>option</I> <I>value</I>?...
<I>pathName</I> <I>axis</I> <B>invtransform</B> <I>value</I>
<I>pathName</I> <I>axis</I> <B>limits</B>
<I>pathName</I> <I>axis</I> <B>transform</B> <I>value</I>
<I>pathName</I> <I>axis</I> <B>use</B> ?<I>axisName</I>?
Designates the axis <I>axisName</I> is to be displayed at this loca-
tion. <I>AxisName</I> can not be already in use at another location.
This command returns the name of the axis currently using this
location.
<B>CROSSHAIRS</B> <B>COMPONENT</B>
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 with-
out redrawing the entire widget.
The following operations are available for cross hairs:
<I>pathName</I> <B>crosshairs</B> <B>cget</B> <I>option</I>
Returns the current value of the cross hairs configuration
option given by <I>option</I>. <I>Option</I> may be any option described
below for the cross hairs <B>configure</B> operation.
<I>pathName</I> <B>crosshairs</B> <B>configure</B> ?<I>option</I> <I>value</I>?...
Queries or modifies the configuration options of the cross
hairs. If <I>option</I> isn't specified, a list describing all the
current options for the cross hairs is returned. If <I>option</I> is
specified, but not <I>value</I>, then a list describing <I>option</I> is
returned. If one or more <I>option</I> and <I>value</I> pairs are specified,
then for each pair, the cross hairs option <I>option</I> is set to
<I>value</I>. The following options are available for cross hairs.
<B>-linewidth</B> <I>pixels</I>
Set the width of the cross hair lines. The default is 1.
<B>-position</B> <I>pos</I>
Specifies the screen position where the cross hairs
intersect. <I>Pos</I> must be in the form "<I>@x,y</I>", where <I>x</I> and <I>y</I>
are the window coordinates of the intersection.
Cross hairs configuration options may be also be set by the
<B>option</B> command. The resource name and class are crosshairs and
Crosshairs respectively. option add *Bar-
chart.Crosshairs.LineWidth 2 option add *Bar-
chart.Crosshairs.Color red
<I>pathName</I> <B>crosshairs</B> <B>off</B>
Turns off the cross hairs.
<I>pathName</I> <B>crosshairs</B> <B>on</B>
Turns on the display of the cross hairs.
<I>pathName</I> <B>crosshairs</B> <B>toggle</B>
Toggles the current state of the cross hairs, alternately map-
ping and unmapping the cross hairs.
</PRE>
<H2>ELEMENTS</H2><PRE>
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.
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.
The following operations are available for elements.
<I>pathName</I> <B>element</B> <B>activate</B> <I>elemName</I> ?<I>index</I>?...
Specifies the data points of element <I>elemName</I> to be drawn using
active foreground and background colors. <I>ElemName</I> is the name
of the element and <I>index</I> is a number representing the index of
the data point. If no indices are present then all data points
become active.
<I>pathName</I> <B>element</B> <B>bind</B> <I>tagName</I> ?<I>sequence</I>? ?<I>command</I>?
Associates <I>command</I> with <I>tagName</I> such that whenever the event
sequence given by <I>sequence</I> occurs for an element with this tag,
<I>command</I> will be invoked. The syntax is similar to the <B>bind</B> com-
mand except that it operates on graph elements, rather than wid-
gets. See the <B>bind</B> manual entry for complete details on <I>sequence</I>
and the substitutions performed on <I>command</I> before invoking it.
<I>pathName</I> <B>element</B> <B>closest</B> <I>x</I> <I>y</I> ?<I>option</I> <I>value</I>?... ?<I>elemName</I>?...
Finds the data point representing the bar closest to the window
coordinates <I>x</I> and <I>y</I> in the element <I>elemName</I>. <I>ElemName</I> 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, "" is returned. The following
<I>option</I>-<I>value</I> pairs are available.
<B>-halo</B> <I>pixels</I>
Specifies a threshold distance where selected data points
are ignored. <I>Pixels</I> is a valid screen distance, such as
2 or 1.2i. If this option isn't specified, then it
defaults to the value of the <B>barchart</B>'s <B>-halo</B> option.
<I>pathName</I> <B>element</B> <B>configure</B> <I>elemName</I> ?<I>elemName</I>... ?<I>option</I> <I>value</I>?...
Queries or modifies the configuration options for elements.
Several elements can be modified at the same time. If <I>option</I>
isn't specified, a list describing all the current options for
<I>elemName</I> is returned. If <I>option</I> is specified, but not <I>value</I>,
then a list describing the option <I>option</I> is returned. If one or
more <I>option</I> and <I>value</I> pairs are specified, then for each pair,
the element option <I>option</I> is set to <I>value</I>. The following
options are valid for elements.
<B>-activepen</B> <I>penName</I>
Specifies pen to use to draw active element. If <I>penName</I>
is "", no active elements will be drawn. The default is
activeLine.
<B>-bindtags</B> <I>tagList</I>
Specifies the binding tags for the element. <I>TagList</I> 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
all.
<B>-background</B> <I>color</I>
Sets the the color of the border around each bar. The
default is white.
<B>-barwidth</B> <I>value</I>
Specifies the width the bars drawn for the element.
<I>Value</I> is the width in X-coordinates. If this option
isn't specified, the width of each bar is the value of
the widget's <B>-barwidth</B> option.
a list of numeric expressions representing the X-Y coor-
dinate pairs of each data point.
<B>-foreground</B> <I>color</I>
Sets the color of the interior of the bars.
<B>-hide</B> <I>boolean</I>
Indicates whether the element is displayed. The default
is no.
<B>-label</B> <I>text</I>
Sets the element's label in the legend. If <I>text</I> is "",
the element will have no entry in the legend. The
default label is the element's name.
<B>-mapx</B> <I>xAxis</I>
Selects the X-axis to map the element's X-coordinates
onto. <I>XAxis</I> must be the name of an axis. The default is
x.
<B>-mapy</B> <I>yAxis</I>
Selects the Y-axis to map the element's Y-coordinates
onto. <I>YAxis</I> must be the name of an axis. The default is
y.
<B>-relief</B> <I>string</I>
Specifies the 3-D effect desired for bars. <I>Relief</I> indi-
cates how the interior of the bar should appear relative
to the surface of the chart; for example, raised means
the bar should appear to protrude from the surface of the
plotting area. The default is raised.
<B>-stipple</B> <I>bitmap</I>
Specifies a stipple pattern with which to draw the bars.
If <I>bitmap</I> is "", then the bar is drawn in a solid fash-
ion.
<B>-xdata</B> <I>xVector</I>
Specifies the x-coordinate vector of the data. <I>XVector</I>
is the name of a BLT vector or a list of numeric expres-
sions.
<B>-ydata</B> <I>yVector</I>
Specifies the y-coordinate vector of the data. <I>YVector</I>
is the name of a BLT vector or a list of numeric expres-
sions.
Element configuration options may also be set by the <B>option</B> com-
mand. The resource names in the option database are prefixed
by elem. option add *Barchart.Element.background blue
<I>pathName</I> <B>element</B> <B>create</B> <I>elemName</I> ?<I>option</I> <I>value</I>?...
<I>pathName</I> <B>element</B> <B>exists</B> <I>elemName</I>
Returns 1 if an element <I>elemName</I> currently exists and 0 other-
wise.
<I>pathName</I> <B>element</B> <B>names</B> ?<I>pattern</I>?...
Returns the elements matching one or more pattern. If no <I>pat-</I>
<I>tern</I> is given, the names of all elements is returned.
<I>pathName</I> <B>element</B> <B>show</B> ?<I>nameList</I>?
Queries or modifies the element display list. The element dis-
play list designates the elements drawn and in what order.
<I>NameList</I> is a list of elements to be displayed in the order they
are named. If there is no <I>nameList</I> argument, the current dis-
play list is returned.
<I>pathName</I> <B>element</B> <B>type</B> <I>elemName</I>
Returns the type of <I>elemName</I>. If the element is a bar element,
the commands returns the string "bar", otherwise it returns
"line".
<B>GRID</B> <B>COMPONENT</B>
Grid lines extend from the major and minor ticks of each axis horizon-
tally or vertically across the plotting area. The following operations
are available for grid lines.
<I>pathName</I> <B>grid</B> <B>cget</B> <I>option</I>
Returns the current value of the grid line configuration option
given by <I>option</I>. <I>Option</I> may be any option described below for
the grid <B>configure</B> operation.
<I>pathName</I> <B>grid</B> <B>configure</B> ?<I>option</I> <I>value</I>?...
Queries or modifies the configuration options for grid lines.
If <I>option</I> isn't specified, a list describing all the current
grid options for <I>pathName</I> is returned. If <I>option</I> is specified,
but not <I>value</I>, then a list describing <I>option</I> is returned. If
one or more <I>option</I> and <I>value</I> pairs are specified, then for each
pair, the grid line option <I>option</I> is set to <I>value</I>. The follow-
ing options are valid for grid lines.
<B>-color</B> <I>color</I>
Sets the color of the grid lines. The default is black.
<B>-dashes</B> <I>dashList</I>
Sets the dash style of the grid lines. <I>DashList</I> 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 <I>dashList</I> is "", the
grid will be solid lines.
<B>-hide</B> <I>boolean</I>
Indicates whether the grid should be drawn. If <I>boolean</I> is
<B>-minor</B> <I>boolean</I>
Indicates whether the grid lines should be drawn for
minor ticks. If <I>boolean</I> is true, the lines will appear
at minor tick intervals. The default is 1.
Grid configuration options may also be set by the <B>option</B> com-
mand. The resource name and class are grid and Grid respec-
tively. option add *Barchart.grid.LineWidth 2 option add *Bar-
chart.Grid.Color black
<I>pathName</I> <B>grid</B> <B>off</B>
Turns off the display the grid lines.
<I>pathName</I> <B>grid</B> <B>on</B>
Turns on the display the grid lines.
<I>pathName</I> <B>grid</B> <B>toggle</B>
Toggles the display of the grid.
<B>LEGEND</B> <B>COMPONENT</B>
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 posi-
tioned anywhere within the plotting area.
The following operations are valid for the legend.
<I>pathName</I> <B>legend</B> <B>activate</B> <I>pattern</I>...
Selects legend entries to be drawn using the active legend col-
ors and relief. All entries whose element names match <I>pattern</I>
are selected. To be selected, the element name must match only
one <I>pattern</I>.
<I>pathName</I> <B>legend</B> <B>bind</B> <I>tagName</I> ?<I>sequence</I>? ?<I>command</I>?
Associates <I>command</I> with <I>tagName</I> such that whenever the event
sequence given by <I>sequence</I> occurs for a legend entry with this
tag, <I>command</I> will be invoked. Implicitly the element names in
the entry are tags. The syntax is similar to the <B>bind</B> command
except that it operates on legend entries, rather than widgets.
See the <B>bind</B> manual entry for complete details on <I>sequence</I> and
the substitutions performed on <I>command</I> before invoking it.
If all arguments are specified then a new binding is created,
replacing any existing binding for the same <I>sequence</I> and <I>tag-</I>
<I>Name</I>. If the first character of <I>command</I> is + then <I>command</I> aug-
ments an existing binding rather than replacing it. If no <I>com-</I>
<I>mand</I> argument is provided then the command currently associated
with <I>tagName</I> and <I>sequence</I> (it's an error occurs if there's no
such binding) is returned. If both <I>command</I> and <I>sequence</I> are
missing then a list of all the event sequences for which bind-
ings have been defined for <I>tagName</I>.
<B>-activebackground</B> <I>color</I>
Sets the background color for active legend entries. All
legend entries marked active (see the legend <B>activate</B>
operation) are drawn using this background color.
<B>-activeborderwidth</B> <I>pixels</I>
Sets the width of the 3-D border around the outside edge
of the active legend entries. The default is 2.
<B>-activeforeground</B> <I>color</I>
Sets the foreground color for active legend entries. All
legend entries marked as active (see the legend <B>activate</B>
operation) are drawn using this foreground color.
<B>-activerelief</B> <I>relief</I>
Specifies the 3-D effect desired for active legend
entries. <I>Relief</I> denotes how the interior of the entry
should appear relative to the legend; for example, raised
means the entry should appear to protrude from the leg-
end, relative to the surface of the legend. The default
is flat.
<B>-anchor</B> <I>anchor</I>
Tells how to position the legend relative to the posi-
tioning point for the legend. This is dependent on the
value of the <B>-position</B> option. The default is center.
left or right
The anchor describes how to position the leg-
end vertically.
top or bottom
The anchor describes how to position the leg-
end horizontally.
@x,y The anchor specifies how to position the leg-
end relative to the positioning point. For
example, if <I>anchor</I> is center then the legend
is centered on the point; if <I>anchor</I> is n then
the legend will be drawn such that the top
center point of the rectangular region occu-
pied by the legend will be at the positioning
point.
plotarea The anchor specifies how to position the leg-
end relative to the plotting area. For exam-
ple, if <I>anchor</I> is center then the legend is
centered in the plotting area; if <I>anchor</I> is
ne then the legend will be drawn such that
occupies the upper right corner of the plot-
ting area.
of the legend (if such border is being drawn; the <B>relief</B>
option determines this). The default is 2 pixels.
<B>-font</B> <I>fontName</I>
<I>FontName</I> specifies a font to use when drawing the labels
of each element into the legend. The default is *-Hel-
vetica-Bold-R-Normal-*-12-120-*.
<B>-foreground</B> <I>color</I>
Sets the foreground color of the text drawn for the ele-
ment's label. The default is black.
<B>-hide</B> <I>boolean</I>
Indicates whether the legend should be displayed. If
<I>boolean</I> is true, the legend will not be draw. The
default is no.
<B>-ipadx</B> <I>pad</I>
Sets the amount of internal padding to be added to the
width of each legend entry. <I>Pad</I> can be a list of one or
two screen distances. If <I>pad</I> has two elements, the left
side of the legend entry is padded by the first distance
and the right side by the second. If <I>pad</I> is just one
distance, both the left and right sides are padded
evenly. The default is 2.
<B>-ipady</B> <I>pad</I>
Sets an amount of internal padding to be added to the
height of each legend entry. <I>Pad</I> can be a list of one or
two screen distances. If <I>pad</I> has two elements, the top
of the entry is padded by the first distance and the bot-
tom by the second. If <I>pad</I> is just one distance, both the
top and bottom of the entry are padded evenly. The
default is 2.
<B>-padx</B> <I>pad</I>
Sets the padding to the left and right exteriors of the
legend. <I>Pad</I> can be a list of one or two screen dis-
tances. If <I>pad</I> has two elements, the left side of the
legend is padded by the first distance and the right side
by the second. If <I>pad</I> has just one distance, both the
left and right sides are padded evenly. The default is
4.
<B>-pady</B> <I>pad</I>
Sets the padding above and below the legend. <I>Pad</I> can be
a list of one or two screen distances. If <I>pad</I> has two
elements, the area above the legend is padded by the
first distance and the area below by the second. If <I>pad</I>
is just one distance, both the top and bottom areas are
padded evenly. The default is 0.
drawn on top of any elements that may overlap it. The
default is no.
<B>-relief</B> <I>relief</I>
Specifies the 3-D effect for the border around the leg-
end. <I>Relief</I> specifies how the interior of the legend
should appear relative to the bar chart; for example,
raised means the legend should appear to protrude from
the bar chart, relative to the surface of the bar chart.
The default is sunken.
Legend configuration options may also be set by the <B>option</B> com-
mand. The resource name and class are legend and Legend respec-
tively. option add *Barchart.legend.Foreground blue option add
*Barchart.Legend.Relief raised
<I>pathName</I> <B>legend</B> <B>deactivate</B> <I>pattern</I>...
Selects legend entries to be drawn using the normal legend col-
ors and relief. All entries whose element names match <I>pattern</I>
are selected. To be selected, the element name must match only
one <I>pattern</I>.
<I>pathName</I> <B>legend</B> <B>get</B> <I>pos</I>
Returns the name of the element whose entry is at the screen
position <I>pos</I> in the legend. <I>Pos</I> must be in the form "<I>@x,y</I>",
where <I>x</I> and <I>y</I> are window coordinates. If the given coordinates
do not lie over a legend entry, "" is returned.
<B>PEN</B> <B>COMPONENTS</B>
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 <B>-weight</B> and <B>-style</B> options).
One pen, called activeBar, 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. .g pen
configure "activeBar" -fg green -bg green4 You can create and use sev-
eral pens. To create a pen, invoke the pen component and its create
operation. .g pen create myPen You map pens to a data element using
either the element's <B>-pen</B> or <B>-activepen</B> options. .g element create
"e1" -xdata $x -ydata $tempData \
-pen myPen 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
<B>-styles</B> option). .g element configure "e1" -styles { myPen 2.0 3.0 }
This says that any data point with a weight between 2.0 and 3.0 is to
be drawn using the pen myPen. All other points are drawn with the ele-
ment's default attributes.
The following operations are available for pen components.
<I>value</I>. The following options are valid for pens.
<B>-background</B> <I>color</I>
Sets the the color of the border around each bar. The
default is white.
<B>-borderwidth</B> <I>pixels</I>
Sets the border width of the 3-D border drawn around the
outside of each bar. The <B>-relief</B> option determines if
such a border is drawn. <I>Pixels</I> must be a valid screen
distance like 2 or 0.25i. The default is 2.
<B>-foreground</B> <I>color</I>
Sets the color of the interior of the bars.
<B>-relief</B> <I>string</I>
Specifies the 3-D effect desired for bars. <I>Relief</I> indi-
cates how the interior of the bar should appear relative
to the surface of the chart; for example, raised means
the bar should appear to protrude from the bar chart,
relative to the surface of the plotting area. The
default is raised.
<B>-stipple</B> <I>bitmap</I>
Specifies a stipple pattern with which to draw the bars.
If <I>bitmap</I> is "", then the bar is drawn in a solid fash-
ion.
<B>-type</B> <I>elemType</I>
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".
Pen configuration options may be also be set by the <B>option</B> com-
mand. The resource class is Pen. The resource names are the
names of the pens. option add *Barchart.Pen.Foreground
blue option add *Barchart.activeBar.foreground green
<I>pathName</I> <B>pen</B> <B>create</B> <I>penName</I> ?<I>option</I> <I>value</I>?...
Creates a new pen by the name <I>penName</I>. No pen by the same name
can already exist. <I>Option</I> and <I>value</I> are described in above in
the pen <B>configure</B> operation.
<I>pathName</I> <B>pen</B> <B>delete</B> ?<I>penName</I>?...
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 ele-
ments.
<I>pathName</I> <B>pen</B> <B>names</B> ?<I>pattern</I>?...
Returns a list of pens matching zero or more patterns. If no
<I>option</I>. <I>Option</I> may be any option described below for the post-
script <B>configure</B> operation.
<I>pathName</I> <B>postscript</B> <B>configure</B> ?<I>option</I> <I>value</I>?...
Queries or modifies the configuration options for PostScript
generation. If <I>option</I> isn't specified, a list describing the
current postscript options for <I>pathName</I> is returned. If <I>option</I>
is specified, but not <I>value</I>, then a list describing <I>option</I> is
returned. If one or more <I>option</I> and <I>value</I> pairs are specified,
then for each pair, the postscript option <I>option</I> is set to
<I>value</I>. The following postscript options are available.
<B>-center</B> <I>boolean</I>
Indicates whether the plot should be centered on the
PostScript page. If <I>boolean</I> is false, the plot will be
placed in the upper left corner of the page. The default
is 1.
<B>-colormap</B> <I>varName</I>
<I>VarName</I> must be the name of a global array variable that
specifies a color mapping from the X color name to Post-
Script. Each element of <I>varName</I> must consist of Post-
Script code to set a particular color value (e.g. ``1.0
1.0 0.0 setrgbcolor''). When generating color informa-
tion in PostScript, the array variable <I>varName</I> 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 <I>varName</I> for a given color, then it uses
the red, green, and blue intensities from the X color.
<B>-colormode</B> <I>mode</I>
Specifies how to output color information. <I>Mode</I> must be
either color (for full color output), gray (convert all
colors to their gray-scale equivalents) or mono (convert
foreground colors to black and background colors to
white). The default mode is color.
<B>-fontmap</B> <I>varName</I>
<I>VarName</I> must be the name of a global array variable that
specifies a font mapping from the X font name to Post-
Script. Each element of <I>varName</I> 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 <I>varName</I> 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). Other-
wise the X font is examined in an attempt to guess what
PostScript font to use. This works only for fonts whose
widget's height. The default is 0.
<B>-landscape</B> <I>boolean</I>
If <I>boolean</I> 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 (``land-
scape'' orientation). Defaults to 0.
<B>-maxpect</B> <I>boolean</I>
Indicates to scale the plot so that it fills the Post-
Script page. The aspect ratio of the barchart is still
retained. The default is 0.
<B>-padx</B> <I>pad</I>
Sets the horizontal padding for the left and right page
borders. The borders are exterior to the plot. <I>Pad</I> can
be a list of one or two screen distances. If <I>pad</I> has two
elements, the left border is padded by the first distance
and the right border by the second. If <I>pad</I> has just one
distance, both the left and right borders are padded
evenly. The default is 1i.
<B>-pady</B> <I>pad</I>
Sets the vertical padding for the top and bottom page
borders. The borders are exterior to the plot. <I>Pad</I> can
be a list of one or two screen distances. If <I>pad</I> has two
elements, the top border is padded by the first distance
and the bottom border by the second. If <I>pad</I> has just one
distance, both the top and bottom borders are padded
evenly. The default is 1i.
<B>-paperheight</B> <I>pixels</I>
Sets the height of the postscript page. This can be used
to select between different page sizes (letter, A4, etc).
The default height is 11.0i.
<B>-paperwidth</B> <I>pixels</I>
Sets the width of the postscript page. This can be used
to select between different page sizes (letter, A4, etc).
The default width is 8.5i.
<B>-width</B> <I>pixels</I>
Sets the width of the plot. This lets you generate a
plot of a width different from that of the widget. If
<I>pixels</I> is 0, the width is the same as the widget's width.
The default is 0.
Postscript configuration options may be also be set by the
<B>option</B> command. The resource name and class are postscript and
Postscript respectively. option add *Barchart.postscript.Deco-
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 <B>-under</B> option.
Markers, in contrast to elements, don't affect the scaling of the coor-
dinate axes. They can also have <I>elastic</I> coordinates (specified by -Inf
and Inf 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
-Inf,-Inf.
The following operations are available for markers.
<I>pathName</I> <B>marker</B> <B>after</B> <I>markerId</I> ?<I>afterId</I>?
Changes the order of the markers, drawing the first marker after
the second. If no second <I>afterId</I> 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.
<I>pathName</I> <B>marker</B> <B>before</B> <I>markerId</I> ?<I>beforeId</I>?
Changes the order of the markers, drawing the first marker
before the second. If no second <I>beforeId</I> 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.
<I>pathName</I> <B>marker</B> <B>bind</B> <I>tagName</I> ?<I>sequence</I>? ?<I>command</I>?
Associates <I>command</I> with <I>tagName</I> such that whenever the event
sequence given by <I>sequence</I> occurs for a marker with this tag,
<I>command</I> will be invoked. The syntax is similar to the <B>bind</B> com-
mand except that it operates on graph markers, rather than wid-
gets. See the <B>bind</B> manual entry for complete details on <I>sequence</I>
and the substitutions performed on <I>command</I> before invoking it.
If all arguments are specified then a new binding is created,
replacing any existing binding for the same <I>sequence</I> and <I>tag-</I>
<I>Name</I>. If the first character of <I>command</I> is + then <I>command</I> aug-
ments an existing binding rather than replacing it. If no <I>com-</I>
<I>mand</I> argument is provided then the command currently associated
with <I>tagName</I> and <I>sequence</I> (it's an error occurs if there's no
such binding) is returned. If both <I>command</I> and <I>sequence</I> are
missing then a list of all the event sequences for which bind-
ings have been defined for <I>tagName</I>.
<I>pathName</I> <B>marker</B> <B>cget</B> <I>option</I>
Returns the current value of the marker configuration option
given by <I>option</I>. <I>Option</I> may be any option described below in
the <B>configure</B> operation.
<I>pathName</I> <B>marker</B> <B>configure</B> <I>markerId</I> ?<I>option</I> <I>value</I>?...
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 all.
<B>-coords</B> <I>coordList</I>
Specifies the coordinates of the marker. <I>CoordList</I> 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 <I>coordList</I> is "", the marker
will not be displayed. The default is "".
<B>-element</B> <I>elemName</I>
Links the marker with the element <I>elemName</I>. The marker
is drawn only if the element is also currently displayed
(see the element's <B>show</B> operation). If <I>elemName</I> is "",
the marker is always drawn. The default is "".
<B>-hide</B> <I>boolean</I>
Indicates whether the marker is drawn. If <I>boolean</I> is
true, the marker is not drawn. The default is no.
<B>-mapx</B> <I>xAxis</I>
Specifies the X-axis to map the marker's X-coordinates
onto. <I>XAxis</I> must the name of an axis. The default is x.
<B>-mapy</B> <I>yAxis</I>
Specifies the Y-axis to map the marker's Y-coordinates
onto. <I>YAxis</I> must the name of an axis. The default is y.
<B>-name</B> <I>markerId</I>
Changes the identifier for the marker. The identifier
<I>markerId</I> can not already be used by another marker. If
this option isn't specified, the marker's name is
uniquely generated.
<B>-under</B> <I>boolean</I>
Indicates whether the marker is drawn below/above data
elements. If <I>boolean</I> is true, the marker is be drawn
underneath the data elements. Otherwise, the marker is
drawn on top of the element. The default is 0.
<B>-xoffset</B> <I>pixels</I>
Specifies a screen distance to offset the marker horizon-
tally. <I>Pixels</I> is a valid screen distance, such as 2 or
1.2i. The default is 0.
Creates a marker of the selected type. <I>Type</I> may be either text,
line, bitmap, image, polygon, or window. This command returns
the marker identifier, used as the <I>markerId</I> argument in the
other marker-related commands. If the <B>-name</B> option is used,
this overrides the normal marker identifier. If the name pro-
vided is already used for another marker, the new marker will
replace the old.
<I>pathName</I> <B>marker</B> <B>delete</B> ?<I>name</I>?...
Removes one of more markers. The graph will automatically be
redrawn without the marker..
<I>pathName</I> <B>marker</B> <B>exists</B> <I>markerId</I>
Returns 1 if the marker <I>markerId</I> exists and 0 otherwise.
<I>pathName</I> <B>marker</B> <B>names</B> ?<I>pattern</I>?
Returns the names of all the markers that currently exist. If
<I>pattern</I> is supplied, only those markers whose names match it
will be returned.
<I>pathName</I> <B>marker</B> <B>type</B> <I>markerId</I>
Returns the type of the marker given by <I>markerId</I>, such as line
or text. If <I>markerId</I> is not a valid a marker identifier, "" is
returned.
<B>BITMAP</B> <B>MARKERS</B>
A bitmap marker displays a bitmap. The size of the bitmap is con-
trolled 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 bit-
map. The bitmap will be stretched or reduced as necessary to fit into
the bounding rectangle.
Bitmap markers are created with the marker's <B>create</B> operation in the
form: <I>pathName</I> <B>marker</B> <B>create</B> <B>bitmap</B> ?<I>option</I> <I>value</I>?... There may be
many <I>option</I>-<I>value</I> pairs, each sets a configuration options for the
marker. These same <I>option</I>-<I>value</I> pairs may be used with the marker's
<B>configure</B> operation.
The following options are specific to bitmap markers:
<B>-background</B> <I>color</I>
Same as the <B>-fill</B> option.
<B>-bitmap</B> <I>bitmap</I>
Specifies the bitmap to be displayed. If <I>bitmap</I> is "", the
marker will not be displayed. The default is "".
<B>-fill</B> <I>color</I>
Sets the background color of the bitmap. If <I>color</I> is the empty
string, no background will be transparent. The default back-
<B>-rotate</B> <I>theta</I>
Sets the rotation of the bitmap. <I>Theta</I> is a real number repre-
senting the angle of rotation in degrees. The marker is first
rotated and then placed according to its anchor position. The
default rotation is 0.0.
<B>IMAGE</B> <B>MARKERS</B>
A image marker displays an image. Image markers are created with the
marker's <B>create</B> operation in the form: <I>pathName</I> <B>marker</B> <B>create</B> <B>image</B>
?<I>option</I> <I>value</I>?... There may be many <I>option</I>-<I>value</I> pairs, each sets a
configuration option for the marker. These same <I>option</I>-<I>value</I> pairs may
be used with the marker's <B>configure</B> operation.
The following options are specific to image markers:
<B>-anchor</B> <I>anchor</I>
<I>Anchor</I> tells how to position the image relative to the position-
ing point for the image. For example, if <I>anchor</I> is center then
the image is centered on the point; if <I>anchor</I> is n then the
image will be drawn such that the top center point of the rect-
angular region occupied by the image will be at the positioning
point. This option defaults to center.
<B>-image</B> <I>image</I>
Specifies the image to be drawn. If <I>image</I> is "", the marker
will not be drawn. The default is "".
<B>LINE</B> <B>MARKERS</B>
A line marker displays one or more connected line segments. Line mark-
ers are created with marker's <B>create</B> operation in the form: <I>pathName</I>
<B>marker</B> <B>create</B> <B>line</B> ?<I>option</I> <I>value</I>?... There may be many <I>option</I>-<I>value</I>
pairs, each sets a configuration option for the marker. These same
<I>option</I>-<I>value</I> pairs may be used with the marker's <B>configure</B> operation.
The following options are specific to line markers:
<B>-dashes</B> <I>dashList</I>
Sets the dash style of the line. <I>DashList</I> 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
<I>dashList</I> is "", the marker line will be solid.
<B>-fill</B> <I>color</I>
Sets the background color of the line. This color is used with
striped lines (see the <B>-dashes</B> option). If <I>color</I> is the empty
string, no background color is drawn (the line will be dashed,
not striped). The default background color is "".
<B>-linewidth</B> <I>pixels</I>
Sets the width of the lines. The default width is 0.
in the form: <I>pathName</I> <B>marker</B> <B>create</B> <B>polygon</B> ?<I>option</I> <I>value</I>?... There
may be many <I>option</I>-<I>value</I> pairs, each sets a configuration option for
the marker. These same <I>option</I>-<I>value</I> pairs may be used with the <B>marker</B>
<B>configure</B> command to change the marker's configuration. The following
options are supported for polygon markers:
<B>-dashes</B> <I>dashList</I>
Sets the dash style of the outline of the polygon. <I>DashList</I> 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 <I>dashList</I> is "", the outline will be a
solid line.
<B>-fill</B> <I>color</I>
Sets the fill color of the polygon. If <I>color</I> is "", then the
interior of the polygon is transparent. The default is white.
<B>-linewidth</B> <I>pixels</I>
Sets the width of the outline of the polygon. If <I>pixels</I> is zero,
no outline is drawn. The default is 0.
<B>-outline</B> <I>color</I>
Sets the color of the outline of the polygon. If the polygon is
stippled (see the <B>-stipple</B> option), then this represents the
foreground color of the stipple. The default is black.
<B>-stipple</B> <I>bitmap</I>
Specifies that the polygon should be drawn with a stippled pat-
tern rather than a solid color. <I>Bitmap</I> specifies a bitmap to use
as the stipple pattern. If <I>bitmap</I> is "", then the polygon is
filled with a solid color (if the <B>-fill</B> option is set). The
default is "".
<B>TEXT</B> <B>MARKERS</B>
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 anno-
tate regions of the graph. Text markers are created with the <B>create</B>
operation in the form: <I>pathName</I> <B>marker</B> <B>create</B> <B>text</B> ?<I>option</I> <I>value</I>?...
There may be many <I>option</I>-<I>value</I> pairs, each sets a configuration option
for the text marker. These same <I>option</I>-<I>value</I> pairs may be used with
the marker's <B>configure</B> operation.
The following options are specific to text markers:
<B>-anchor</B> <I>anchor</I>
<I>Anchor</I> tells how to position the text relative to the position-
ing point for the text. For example, if <I>anchor</I> is center then
the text is centered on the point; if <I>anchor</I> is n 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 center.
<B>-justify</B> <I>justify</I>
Specifies how the text should be justified. This matters only
when the marker contains more than one line of text. <I>Justify</I>
must be left, right, or center. The default is center.
<B>-outline</B> <I>color</I>
Sets the color of the text. The default value is black.
<B>-padx</B> <I>pad</I>
Sets the padding to the left and right exteriors of the text.
<I>Pad</I> can be a list of one or two screen distances. If <I>pad</I> has
two elements, the left side of the text is padded by the first
distance and the right side by the second. If <I>pad</I> has just one
distance, both the left and right sides are padded evenly. The
default is 4.
<B>-pady</B> <I>pad</I>
Sets the padding above and below the text. <I>Pad</I> can be a list of
one or two screen distances. If <I>pad</I> has two elements, the area
above the text is padded by the first distance and the area
below by the second. If <I>pad</I> is just one distance, both the top
and bottom areas are padded evenly. The default is 4.
<B>-rotate</B> <I>theta</I>
Specifies the number of degrees to rotate the text. <I>Theta</I> 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 0.0.
<B>-text</B> <I>text</I>
Specifies the text of the marker. The exact way the text is
displayed may be affected by other options such as <B>-anchor</B> or
<B>-rotate</B>.
<B>WINDOW</B> <B>MARKERS</B>
A window marker displays a widget at a given position. Window markers
are created with the marker's <B>create</B> operation in the form: <I>pathName</I>
<B>marker</B> <B>create</B> <B>window</B> ?<I>option</I> <I>value</I>?... There may be many <I>option</I>-<I>value</I>
pairs, each sets a configuration option for the marker. These same
<I>option</I>-<I>value</I> pairs may be used with the marker's <B>configure</B> command.
The following options are specific to window markers:
<B>-anchor</B> <I>anchor</I>
<I>Anchor</I> tells how to position the widget relative to the posi-
tioning point for the widget. For example, if <I>anchor</I> is center
then the widget is centered on the point; if <I>anchor</I> is n 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 center.
</PRE>
<H2>GRAPH COMPONENT BINDINGS</H2><PRE>
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 <B>Enter</B>, <B>Leave</B>, <B>ButtonPress</B>, <B>Motion</B>,
and <B>KeyPress</B>).
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 com-
mands will be invoked if both items are picked.
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
<B>-bindtags</B> 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 com-
mand.
The <B>-bindtags</B> 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 <B>-bindtags</B> option
doesn't change this.
</PRE>
<H2>C LANGUAGE API</H2><PRE>
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 for-
mat.
Data can manipulated from the C language using BLT vectors. You spec-
ify 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.
From Tcl, create the vectors and configure the element to use them.
vector X Y .g element configure line1 -xdata X -ydata Y To set data
points from C, you pass the values as arrays of doubles using the
<B>Blt_ResetVector</B> 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. #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
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.
<B>o</B> Try to minimize the number of data points. The more data points
looked at, the more work the bar chart must do.
<B>o</B> If your data is generated as floating point values, the time required
to convert the data values to and from ASCII strings can be signifi-
cant, especially when there any many data points. You can avoid the
redundant string-to-decimal conversions using the C API to BLT vec-
tors.
<B>o</B> Don't stipple or dash the element. Solid bars are much faster.
<B>o</B> If you update data elements frequently, try turning off the widget's
<B>-bufferelements</B> 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 sim-
ply 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.
</PRE>
<H2>LIMITATIONS</H2><PRE>
Auto-scale routines do not use requested min/max limits as boundaries
when the axis is logarithmically scaled.
The PostScript output generated for polygons with more than 1500 points
may exceed the limits of some printers (See PostScript Language Refer-
ence Manual, page 568). The work-around is to break the polygon into
separate pieces.
</PRE>
<H2>KEYWORDS</H2><PRE>
bar chart, widget
BLT BLT_VERSION barchart(n)
</PRE>
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