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Diffstat (limited to 'doc/canvas.n')
| -rw-r--r-- | doc/canvas.n | 372 |
1 files changed, 239 insertions, 133 deletions
diff --git a/doc/canvas.n b/doc/canvas.n index 5ea3035..9338b8d 100644 --- a/doc/canvas.n +++ b/doc/canvas.n @@ -15,19 +15,19 @@ canvas \- Create and manipulate canvas widgets .SH SYNOPSIS \fBcanvas\fR \fIpathName \fR?\fIoptions\fR? .SO -\-background \-insertborderwidth \-selectborderwidth -\-borderwidth \-insertofftime \-selectforeground -\-cursor \-insertontime \-takefocus -\-highlightbackground \-insertwidth \-xscrollcommand -\-highlightcolor \-relief \-yscrollcommand -\-highlightthickness \-state -\-insertbackground \-selectbackground +\-background \-borderwidth \-cursor +\-highlightbackground \-highlightcolor \-highlightthickness +\-insertbackground \-insertborderwidth \-insertofftime +\-insertontime \-insertwidth \-relief +\-selectbackground \-selectborderwidth \-selectforeground +\-takefocus \-xscrollcommand \-yscrollcommand .SE .SH "WIDGET-SPECIFIC OPTIONS" .OP \-closeenough closeEnough CloseEnough Specifies a floating-point value indicating how close the mouse cursor -must be to an item before it is considered to be ``inside'' the item. -Defaults to 1.0. +must be to an item before it is considered to be +.QW inside +the item. Defaults to 1.0. .OP \-confine confine Confine Specifies a boolean value that indicates whether or not it should be allowable to set the canvas's view outside the region defined by the @@ -80,7 +80,6 @@ are selected) will also be \fByScrollIncrement\fR. If the value of this option is less than or equal to zero, then vertical scrolling is unconstrained. .BE - .SH INTRODUCTION .PP The \fBcanvas\fR command creates a new window (given @@ -110,8 +109,9 @@ The items in a canvas are ordered for purposes of display, with the first item in the display list being displayed first, followed by the next item in the list, and so on. Items later in the display list obscure those that are -earlier in the display list and are sometimes referred to -as being ``on top'' of earlier items. +earlier in the display list and are sometimes referred to as being +.QW "on top" +of earlier items. When a new item is created it is placed at the end of the display list, on top of everything else. Widget commands may be used to re-arrange the order of the @@ -134,11 +134,15 @@ canvas widget. Each item may also have any number of \fItags\fR associated with it. A tag is just a string of characters, and it may take any form except that of an integer. -For example, ``x123'' is OK but ``123'' isn't. +For example, +.QW x123 +is OK but +.QW 123 +is not. The same tag may be associated with many different items. This is commonly done to group items in various interesting -ways; for example, all selected items might be given the -tag ``selected''. +ways; for example, all selected items might be given the tag +.QW selected . .PP The tag \fBall\fR is implicitly associated with every item in the canvas; it may be used to invoke operations on @@ -147,7 +151,8 @@ all the items in the canvas. The tag \fBcurrent\fR is managed automatically by Tk; it applies to the \fIcurrent item\fR, which is the topmost item whose drawn area covers the position of -the mouse cursor. +the mouse cursor (different item types interpret this in varying ways; see the +individual item type documentation for details). If the mouse is not in the canvas widget or is not over an item, then no item has the \fBcurrent\fR tag. .PP @@ -162,8 +167,12 @@ an argument specifies either an id that selects a single item or a tag that selects zero or more items. .PP \fItagOrId\fR may contain a logical expressions of -tags by using operators: '&&', '||', '^' '!', and parenthesized -subexpressions. For example: +tags by using operators: +.QW \fB&&\fR , +.QW \fB||\fR , +.QW \fB^\fR , +.QW \fB!\fR , +and parenthesized subexpressions. For example: .CS .c find withtag {(a&&!b)||(!a&&b)} .CE @@ -171,7 +180,11 @@ or equivalently: .CS .c find withtag {a^b} .CE -will find only those items with either "a" or "b" tags, but not both. +will find only those items with either +.QW a +or +.QW b +tags, but not both. .PP Some widget commands only operate on a single item at a time; if \fItagOrId\fR is specified in a way that @@ -193,12 +206,10 @@ the screen; if it is \fBc\fR then the distance is in centimeters; \fBi\fR means inches, and \fBp\fR means printers points (1/72 inch). Larger y-coordinates refer to points lower on the screen; larger x-coordinates refer to points farther to the right. -.VS Coordinates can be specified either as an even number of parameters, or as a single list parameter containing an even number of x and y coordinate values. -.VE -.SH TRANSFORMATIONS +.SS TRANSFORMATIONS .PP Normally the origin of the canvas coordinate system is at the upper-left corner of the window containing the canvas. @@ -238,7 +249,7 @@ support as many of these forms as practical. Note that it is possible to refer to the character just after the last one in the text item; this is necessary for such tasks as inserting new text at the end of the item. -Lines and Polygons don't support the insertion cursor +Lines and Polygons do not support the insertion cursor and the selection. Their indices are supposed to be even always, because coordinates always appear in pairs. .TP 10 @@ -267,11 +278,11 @@ is drawn in this item. Not valid for lines and polygons. .TP 10 \fBsel.first\fR Refers to the first selected character in the item. -If the selection isn't in this item then this form is illegal. +If the selection is not in this item then this form is illegal. .TP 10 \fBsel.last\fR Refers to the last selected character in the item. -If the selection isn't in this item then this form is illegal. +If the selection is not in this item then this form is illegal. .TP 10 \fB@\fIx,y\fR Refers to the character or coordinate at the point given by \fIx\fR and @@ -286,24 +297,32 @@ Many items support the notion of a dash pattern for outlines. .PP The first possible syntax is a list of integers. Each element represents the number of pixels of a line segment. Only the odd -segments are drawn using the "outline" color. The other segments -are drawn transparent. +segments are drawn using the +.QW outline +color. The other segments are drawn transparent. .PP The second possible syntax is a character list containing only -5 possible characters \fB[.,-_ ]\fR. The space can be used -to enlarge the space between other line elements, and can not +5 possible characters +.QW "\fB.,\-_ \fR" . +The space can be used +to enlarge the space between other line elements, and cannot occur as the first position in the string. Some examples: - -dash . = -dash {2 4} - -dash - = -dash {6 4} - -dash -. = -dash {6 4 2 4} - -dash -.. = -dash {6 4 2 4 2 4} - -dash {. } = -dash {2 8} - -dash , = -dash {4 4} +.CS +\-dash . \(-> \-dash {2 4} +\-dash \- \(-> \-dash {6 4} +\-dash \-. \(-> \-dash {6 4 2 4} +\-dash \-.. \(-> \-dash {6 4 2 4 2 4} +\-dash {. } \(-> \-dash {2 8} +\-dash , \(-> \-dash {4 4} +.CE .PP The main difference of this syntax with the previous is that it is shape-conserving. This means that all values in the dash list will be multiplied by the line width before display. This -assures that "." will always be displayed as a dot and "-" +assures that +.QW . +will always be displayed as a dot and +.QW \- always as a dash regardless of the line width. .PP On systems which support only a limited set of dash patterns, the dash @@ -328,7 +347,7 @@ The following widget commands are possible for canvas widgets: For each item that meets the constraints specified by \fIsearchSpec\fR and the \fIarg\fRs, add \fItag\fR to the list of tags associated with the item if it -isn't already present on that list. +is not already present on that list. It is possible that no items will satisfy the constraints given by \fIsearchSpec\fR and \fIarg\fRs, in which case the command has no effect. @@ -391,7 +410,9 @@ Selects all the items given by \fItagOrId\fR. \fIpathName \fBbbox \fItagOrId\fR ?\fItagOrId tagOrId ...\fR? Returns a list with four elements giving an approximate bounding box for all the items named by the \fItagOrId\fR arguments. -The list has the form ``\fIx1 y1 x2 y2\fR'' such that the drawn +The list has the form +.QW "\fIx1 y1 x2 y2\fR" +such that the drawn areas of all the named elements are within the region bounded by \fIx1\fR on the left, \fIx2\fR on the right, \fIy1\fR on the top, and \fIy2\fR on the bottom. @@ -414,8 +435,9 @@ on the syntax of \fIsequence\fR and the substitutions performed on \fIcommand\fR before invoking it. If all arguments are specified then a new binding is created, replacing any existing binding for the same \fIsequence\fR and \fItagOrId\fR -(if the first character of \fIcommand\fR is ``+'' then \fIcommand\fR -augments an existing binding rather than replacing it). +(if the first character of \fIcommand\fR is +.QW + +then \fIcommand\fR augments an existing binding rather than replacing it). In this case the return value is an empty string. If \fIcommand\fR is omitted then the command returns the \fIcommand\fR associated with \fItagOrId\fR and \fIsequence\fR (an error occurs @@ -428,8 +450,9 @@ defined for \fItagOrId\fR. The only events for which bindings may be specified are those related to the mouse and keyboard (such as \fBEnter\fR, \fBLeave\fR, \fBButtonPress\fR, \fBMotion\fR, and \fBKeyPress\fR) or virtual events. -The handling of events in canvases uses the current item defined in ITEM -IDS AND TAGS above. \fBEnter\fR and \fBLeave\fR events trigger for an +The handling of events in canvases uses the current item defined in +\fBITEM IDS AND TAGS\fR above. \fBEnter\fR and \fBLeave\fR events +trigger for an item when it becomes the current item or ceases to be the current item; note that these events are different than \fBEnter\fR and \fBLeave\fR events for windows. Mouse-related events are directed to the current @@ -519,11 +542,11 @@ This command returns the id for the new item. \fIpathName \fBdchars \fItagOrId first \fR?\fIlast\fR? For each item given by \fItagOrId\fR, delete the characters, or coordinates, in the range given by \fIfirst\fR and \fIlast\fR, inclusive. -If some of the items given by \fItagOrId\fR don't support +If some of the items given by \fItagOrId\fR do not support indexing operations then they ignore dchars. Text items interpret \fIfirst\fR and \fIlast\fR as indices to a character, line and polygon items interpret them indices to a coordinate (an x,y pair). -Indices are described in INDICES above. +Indices are described in \fBINDICES\fR above. If \fIlast\fR is omitted, it defaults to \fIfirst\fR. This command returns an empty string. .TP @@ -535,7 +558,7 @@ an empty string. For each of the items given by \fItagOrId\fR, delete the tag given by \fItagToDelete\fR from the list of those associated with the item. -If an item doesn't have the tag \fItagToDelete\fR then +If an item does not have the tag \fItagToDelete\fR then the item is unaffected by the command. If \fItagToDelete\fR is omitted then it defaults to \fItagOrId\fR. This command returns an empty string. @@ -554,8 +577,8 @@ Set the keyboard focus for the canvas widget to the item given by If \fItagOrId\fR refers to several items, then the focus is set to the first such item in the display list that supports the insertion cursor. -If \fItagOrId\fR doesn't refer to any items, or if none of them -support the insertion cursor, then the focus isn't changed. +If \fItagOrId\fR does not refer to any items, or if none of them +support the insertion cursor, then the focus is not changed. If \fItagOrId\fR is an empty string, then the focus item is reset so that no item has the focus. If \fItagOrId\fR is not specified then the command returns the @@ -568,12 +591,12 @@ the insertion cursor and all keyboard events will be directed to that item. The focus item within a canvas and the focus window on the screen (set with the \fBfocus\fR command) are totally independent: -a given item doesn't actually have the input focus unless (a) +a given item does not actually have the input focus unless (a) its canvas is the focus window and (b) the item is the focus item within the canvas. In most cases it is advisable to follow the \fBfocus\fR widget command with the \fBfocus\fR command to set the focus window to -the canvas (if it wasn't there already). +the canvas (if it was not there already). .RE .TP \fIpathName \fBgettags\fR \fItagOrId\fR @@ -581,27 +604,27 @@ Return a list whose elements are the tags associated with the item given by \fItagOrId\fR. If \fItagOrId\fR refers to more than one item, then the tags are returned from the first such item in the display list. -If \fItagOrId\fR doesn't refer to any items, or if the item +If \fItagOrId\fR does not refer to any items, or if the item contains no tags, then an empty string is returned. .TP \fIpathName \fBicursor \fItagOrId index\fR Set the position of the insertion cursor for the item(s) given by \fItagOrId\fR to just before the character whose position is given by \fIindex\fR. -If some or all of the items given by \fItagOrId\fR don't support +If some or all of the items given by \fItagOrId\fR do not support an insertion cursor then this command has no effect on them. -See INDICES above for a description of the +See \fBINDICES\fR above for a description of the legal forms for \fIindex\fR. Note: the insertion cursor is only displayed in an item if that item currently has the keyboard focus (see the widget command \fBfocus\fR, below), but the cursor position may -be set even when the item doesn't have the focus. +be set even when the item does not have the focus. This command returns an empty string. .TP \fIpathName \fBindex \fItagOrId index\fR This command returns a decimal string giving the numerical index within \fItagOrId\fR corresponding to \fIindex\fR. \fIIndex\fR gives a textual description of the desired position -as described in INDICES above. +as described in \fBINDICES\fR above. Text items interpret \fIindex\fR as an index to a character, line and polygon items interpret it as an index to a coordinate (an x,y pair). The return value is guaranteed to lie between 0 and the number @@ -618,7 +641,7 @@ Text items interpret \fIbeforeThis\fR as an index to a character, line and polygon items interpret it as an index to a coordinate (an x,y pair). For lines and polygons the \fIstring\fR must be a valid coordinate sequence. -See INDICES above for information about the forms allowed +See \fBINDICES\fR above for information about the forms allowed for \fIbeforeThis\fR. This command returns an empty string. .TP @@ -691,7 +714,7 @@ Note: by default Postscript is only generated for information that appears in the canvas's window on the screen. If the canvas is freshly created it may still have its initial size of 1x1 pixel so nothing will appear in the Postscript. To get around this problem -either invoke the "update" command to wait for the canvas window +either invoke the \fBupdate\fR command to wait for the canvas window to reach its final size, or else use the \fB\-width\fR and \fB\-height\fR options to specify the area of the canvas to print. The \fIoption\fR\-\fIvalue\fR argument pairs provide additional @@ -703,13 +726,14 @@ options are supported: \fIVarName\fR must be the name of an array variable that specifies a color mapping to use in the Postscript. Each element of \fIvarName\fR must consist of Postscript -code to set a particular color value (e.g. ``\fB1.0 1.0 0.0 setrgbcolor\fR''). +code to set a particular color value (e.g. +.QW "\fB1.0 1.0 0.0 setrgbcolor\fR" ). When outputting color information in the Postscript, Tk checks to see if there is an element of \fIvarName\fR with the same name as the color. If so, Tk uses the value of the element as the Postscript command to set the color. -If this option hasn't been specified, or if there isn't an entry +If this option has not been specified, or if there is no entry in \fIvarName\fR for a given color, then Tk uses the red, green, and blue intensities from the X color. .TP @@ -721,7 +745,7 @@ to black or white). .TP \fB\-file \fIfileName\fR Specifies the name of the file in which to write the Postscript. -If this option isn't specified then the Postscript is returned as the +If this option is not specified then the Postscript is returned as the result of the command instead of being written to a file. .TP \fB\-fontmap \fIvarName\fR @@ -792,9 +816,10 @@ Defaults to the center of the page. \fIBoolean\fR specifies whether 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). +the short dimension of the page +.PQ portrait orientation ; +in rotated output the x-axis runs along the long dimension of the page +.PQ landscape orientation . Defaults to non-rotated. .TP \fB\-width \fIsize\fR @@ -875,7 +900,7 @@ an item that supports indexing and selection; if it refers to multiple items then the first of these that supports indexing and the selection is used. \fIIndex\fR gives a textual description of a position -within \fItagOrId\fR, as described in INDICES above. +within \fItagOrId\fR, as described in \fBINDICES\fR above. .RS .TP \fIpathName \fBselect adjust \fItagOrId index\fR @@ -885,14 +910,14 @@ end of the selection to be at \fIindex\fR (i.e. including but not going beyond \fIindex\fR). The other end of the selection is made the anchor point for future \fBselect to\fR commands. -If the selection isn't currently in \fItagOrId\fR then +If the selection is not currently in \fItagOrId\fR then this command behaves the same as the \fBselect to\fR widget command. Returns an empty string. .TP \fIpathName \fBselect clear\fR Clear the selection if it is in this widget. -If the selection isn't in this widget then the command +If the selection is not in this widget then the command has no effect. Returns an empty string. .TP @@ -900,7 +925,7 @@ Returns an empty string. Set the selection anchor point for the widget to be just before the character given by \fIindex\fR in the item given by \fItagOrId\fR. -This command doesn't change the selection; it just sets +This command does not change the selection; it just sets the fixed end of the selection for future \fBselect to\fR commands. Returns an empty string. @@ -920,7 +945,7 @@ it will include the character given by the anchor point only if \fIindex\fR is greater than or equal to the anchor point. The anchor point is determined by the most recent \fBselect adjust\fR or \fBselect from\fR command for this widget. -If the selection anchor point for the widget isn't currently in +If the selection anchor point for the widget is not currently in \fItagOrId\fR, then it is set to the same character given by \fIindex\fR. Returns an empty string. @@ -931,7 +956,7 @@ Returns the type of the item given by \fItagOrId\fR, such as \fBrectangle\fR or \fBtext\fR. If \fItagOrId\fR refers to more than one item, then the type of the first item in the display list is returned. -If \fItagOrId\fR doesn't refer to any items at all then +If \fItagOrId\fR does not refer to any items at all then an empty string is returned. .TP \fIpathName \fBxview \fR?\fIargs\fR? @@ -1015,14 +1040,14 @@ first, the form of the \fBcreate\fR command used to create instances of the type; and second, a set of configuration options for items of that type, which may be used in the \fBcreate\fR and \fBitemconfigure\fR widget commands. -Most items don't support indexing or selection or the commands +Most items do not support indexing or selection or the commands related to them, such as \fBindex\fR and \fBinsert\fR. Where items do support these facilities, it is noted explicitly in the descriptions below. At present, text, line and polygon items provide this support. For lines and polygons the indexing facility is used to manipulate the coordinates of the item. -.SH "COMMON ITEM OPTIONS" +.SS "COMMON ITEM OPTIONS" .PP Many items share a common set of options. These options are explained here, and then referred to be each widget type for brevity. @@ -1037,12 +1062,12 @@ This option specifies dash patterns for the normal, active state, and disabled state of an item. \fIpattern\fR may have any of the forms accepted by \fBTk_GetDash\fR. If the dash options are omitted then the default is a solid outline. -See "DASH PATTERNS" for more information. +See \fBDASH PATTERNS\fR for more information. .TP \fB\-dashoffset \fIoffset\fR The starting \fIoffset\fR in pixels into the pattern provided by the \fB\-dash\fR option. \fB\-dashoffset\fR is ignored if there is no -\fB-dash\fR pattern. The \fIoffset\fR may have any of the forms described +\fB\-dash\fR pattern. The \fIoffset\fR may have any of the forms described in the \fBCOORDINATES\fR section above. .TP \fB\-fill \fIcolor\fR @@ -1076,7 +1101,7 @@ Specifies the offset of stipples. The offset value can be of the form first case the origin is the origin of the toplevel of the current window. For the canvas itself and canvas objects the origin is the canvas origin, but putting \fB#\fR in front of the coordinate pair indicates using the -toplevel origin instead. For canvas objects, the \fB-offset\fR option is +toplevel origin instead. For canvas objects, the \fB\-offset\fR option is used for stippling as well. For the line and polygon canvas items you can also specify an index as argument, which connects the stipple origin to one of the coordinate points of the line/polygon. @@ -1091,13 +1116,24 @@ outline of the item in its normal, active and disabled states. Indicates that the outline for the item should be drawn with a stipple pattern; \fIbitmap\fR specifies the stipple pattern to use, in any of the forms accepted by \fBTk_GetBitmap\fR. -If the \fB\-outline\fR option hasn't been specified then this option +If the \fB\-outline\fR option has not been specified then this option has no effect. If \fIbitmap\fR is an empty string (the default), then the outline is drawn in a solid fashion. \fINote that stipples are not well supported on platforms that do not use X11 as their drawing API.\fR .TP +\fB\-outlineoffset \fIoffset\fR +. +Specifies the offset of the stipple pattern used for outlines. The +offset value can be of the form +.QW \fIx\fB,\fIy\fR +or the description of a side (one of \fBn\fR, \fBne\fR, \fBe\fR, +\fBse\fR, \fBs\fR, \fBsw\fR, \fBw\fR, \fBnw\fR, or \fBcenter\fR). This +option only has an effect when the outline is drawn as a stipple +pattern, and is only supported under X11. +.\" TODO: What does this actually do? What do the acceptable forms mean?! +.TP \fB\-stipple \fIbitmap\fR .TP \fB\-activestipple \fIbitmap\fR @@ -1107,7 +1143,7 @@ This option specifies stipple patterns that should be used to fill the item in its normal, active and disabled states. \fIbitmap\fR specifies the stipple pattern to use, in any of the forms accepted by \fBTk_GetBitmap\fR. -If the \fB\-fill\fR option hasn't been specified then this option +If the \fB\-fill\fR option has not been specified then this option has no effect. If \fIbitmap\fR is an empty string (the default), then filling is done in a solid fashion. @@ -1156,8 +1192,10 @@ After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. An arc item becomes the current item when the mouse pointer is +over any part that is painted or (when fully transparent) that would be +painted if both the \fB\-fill\fR and \fB\-outline\fR options were non-empty. +.PP The following standard options are supported by arcs: .CS \-dash @@ -1171,6 +1209,7 @@ The following standard options are supported by arcs: \-outline \-activeoutline \-disabledoutline +\-outlineoffset \-outlinestipple \-activeoutlinestipple \-disabledoutlinestipple @@ -1190,7 +1229,7 @@ Specifies the size of the angular range occupied by the arc. The arc's range extends for \fIdegrees\fR degrees counter-clockwise from the starting angle given by the \fB\-start\fR option. \fIDegrees\fR may be negative. -If it is greater than 360 or less than -360, then \fIdegrees\fR +If it is greater than 360 or less than \-360, then \fIdegrees\fR modulo 360 is used as the extent. .TP \fB\-start \fIdegrees\fR @@ -1219,15 +1258,17 @@ Bitmaps are created with widget commands of the following form: \fIpathName \fBcreate bitmap \fIx y \fR?\fIoption value option value ...\fR? \fIpathName \fBcreate bitmap \fIcoordList\fR ?\fIoption value option value ...\fR? .CE -The arguments \fIx\fR and \fIy\fR or \fIcoordList\fR specify the coordinates of a +The arguments \fIx\fR and \fIy\fR or \fIcoordList\fR (which must have two +elements) specify the coordinates of a point used to position the bitmap on the display (see the \fB\-anchor\fR option below for more information on how bitmaps are displayed). After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. A bitmap item becomes the current item when the mouse pointer +is over any part of its bounding box. +.PP The following standard options are supported by bitmaps: .CS \-state @@ -1249,10 +1290,11 @@ This option defaults to \fBcenter\fR. \fB\-activebackground \fIcolor\fR .TP \fB\-disabledbackground \fIcolor\fR -Specifies the color to use for each of the bitmap's '0' valued pixels -in its normal, active and disabled states. +Specifies the color to use for each of the bitmap's +.QW 0 +valued pixels in its normal, active and disabled states. \fIColor\fR may have any of the forms accepted by \fBTk_GetColor\fR. -If this option isn't specified, or if it is specified as an empty +If this option is not specified, or if it is specified as an empty string, then nothing is displayed where the bitmap pixels are 0; this produces a transparent effect. .TP @@ -1270,8 +1312,9 @@ disabled states. \fB\-activeforeground \fIcolor\fR .TP \fB\-disabledforeground \fIcolor\fR -Specifies the color to use for each of the bitmap's '1' valued pixels -in its normal, active and disabled states. +Specifies the color to use for each of the bitmap's +.QW 1 +valued pixels in its normal, active and disabled states. \fIColor\fR may have any of the forms accepted by \fBTk_GetColor\fR and defaults to \fBblack\fR. .SH "IMAGE ITEMS" @@ -1290,8 +1333,9 @@ After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. An image item becomes the current item when the mouse pointer +is over any part of its bounding box. +.PP The following standard options are supported by images: .CS \-state @@ -1335,8 +1379,10 @@ After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. A line item is the current item whenever the mouse pointer is +over any segment of the line, whether drawn or not and whether or not the line +is smoothed. +.PP The following standard options are supported by lines: .CS \-dash @@ -1377,14 +1423,16 @@ The second element gives the distance along the line from the trailing points of the arrowhead to the tip, and the third element gives the distance from the outside edge of the line to the trailing points. -If this option isn't specified then Tk picks a ``reasonable'' shape. +If this option is not specified then Tk picks a +.QW reasonable +shape. .TP \fB\-capstyle \fIstyle\fR Specifies the ways in which caps are to be drawn at the endpoints of the line. \fIStyle\fR may have any of the forms accepted by \fBTk_GetCapStyle\fR (\fBbutt\fR, \fBprojecting\fR, or \fBround\fR). -If this option isn't specified then it defaults to \fBbutt\fR. +If this option is not specified then it defaults to \fBbutt\fR. Where arrowheads are drawn the cap style is ignored. .TP \fB\-joinstyle \fIstyle\fR @@ -1392,27 +1440,38 @@ Specifies the ways in which joints are to be drawn at the vertices of the line. \fIStyle\fR may have any of the forms accepted by \fBTk_GetCapStyle\fR (\fBbevel\fR, \fBmiter\fR, or \fBround\fR). -If this option isn't specified then it defaults to \fBmiter\fR. +If this option is not specified then it defaults to \fBround\fR. If the line only contains two points then this option is irrelevant. .TP \fB\-smooth \fIsmoothMethod\fR \fIsmoothMethod\fR must have one of the forms accepted by -\fBTcl_GetBoolean\fR or a line smoothing method. Only \fBbezier\fR is -supported in the core, but more can be added at runtime. If a boolean +\fBTcl_GetBoolean\fR or a line smoothing method. +.VS 8.5 +Only \fBtrue\fR and \fBraw\fR are +supported in the core (with \fBbezier\fR being an alias for \fBtrue\fR), but more can be added at runtime. If a boolean false value or empty string is given, no smoothing is applied. A boolean -truth value assume \fBbezier\fR smoothing. -It indicates whether or not the line should be drawn as a curve. -If so, the line is rendered as a set of parabolic splines: one spline +truth value assumes \fBtrue\fR smoothing. +If the smoothing method is \fBtrue\fR, this indicates that the line +should be drawn as a curve, rendered as a set of quadratic splines: one spline is drawn for the first and second line segments, one for the second and third, and so on. Straight-line segments can be generated within a curve by duplicating the end-points of the desired line segment. +If the smoothing method is \fBraw\fR, this indicates that the line +should also be drawn as a curve but where the list of coordinates is +such that the first coordinate pair (and every third coordinate pair +thereafter) is a knot point on a cubic Bezier curve, and the other +coordinates are control points on the cubic Bezier curve. Straight +line segments can be generated within a curve by making control points +equal to their neighbouring knot points. If the last point is a +control point and not a knot point, the point is repeated (one or two +times) so that it also becomes a knot point. +.VE 8.5 .TP \fB\-splinesteps \fInumber\fR Specifies the degree of smoothness desired for curves: each spline will be approximated with \fInumber\fR line segments. This -option is ignored unless the \fB\-smooth\fR option is true. - +option is ignored unless the \fB\-smooth\fR option is true or \fBraw\fR. .SH "OVAL ITEMS" .PP Items of type \fBoval\fR appear as circular or oval regions on @@ -1434,8 +1493,10 @@ After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. An oval item becomes the current item when the mouse pointer is +over any part that is painted or (when fully transparent) that would be +painted if both the \fB\-fill\fR and \fB\-outline\fR options were non-empty. +.PP The following standard options are supported by ovals: .CS \-dash @@ -1449,6 +1510,7 @@ The following standard options are supported by ovals: \-outline \-activeoutline \-disabledoutline +\-outlineoffset \-outlinestipple \-activeoutlinestipple \-disabledoutlinestipple @@ -1481,8 +1543,10 @@ After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. A polygon item is the current item whenever the mouse pointer +is over any part of the polygon, whether drawn or not and whether or not the +outline is smoothed. +.PP The following standard options are supported by polygons: .CS \-dash @@ -1515,25 +1579,41 @@ Specifies the ways in which joints are to be drawn at the vertices of the outline. \fIStyle\fR may have any of the forms accepted by \fBTk_GetCapStyle\fR (\fBbevel\fR, \fBmiter\fR, or \fBround\fR). -If this option isn't specified then it defaults to \fBmiter\fR. +If this option is not specified then it defaults to \fBround\fR. .TP \fB\-smooth \fIboolean\fR -\fIBoolean\fR must have one of the forms accepted by \fBTcl_GetBoolean\fR. -It indicates whether or not the polygon should be drawn with a -curved perimeter. -If so, the outline of the polygon becomes a set of parabolic splines, -one spline for the first and second line segments, one for the second -and third, and so on. Straight-line segments can be generated in a -smoothed polygon by duplicating the end-points of the desired line segment. +\fIBoolean\fR must have one of the forms accepted by \fBTcl_GetBoolean\fR +.VS 8.5 +or a line smoothing method. Only \fBtrue\fR and \fBraw\fR are +supported in the core (with \fBbezier\fR being an alias for \fBtrue\fR), but more can be added at runtime. If a boolean +false value or empty string is given, no smoothing is applied. A boolean +truth value assumes \fBtrue\fR smoothing. +If the smoothing method is \fBtrue\fR, this indicates that the polygon +should be drawn as a curve, rendered as a set of quadratic splines: one spline +is drawn for the first and second line segments, one for the second +and third, and so on. Straight-line segments can be generated within +a curve by duplicating the end-points of the desired line segment. +If the smoothing method is \fBraw\fR, this indicates that the polygon +should also be drawn as a curve but where the list of coordinates is +such that the first coordinate pair (and every third coordinate pair +thereafter) is a knot point on a cubic Bezier curve, and the other +coordinates are control points on the cubic Bezier curve. Straight +line segments can be venerated within a curve by making control points +equal to their neighbouring knot points. If the last point is not the +second point of a pair of control points, the point is repeated (one or two +times) so that it also becomes the second point of a pair of control +points (the associated knot point will be the first control point). +.VE 8.5 .TP \fB\-splinesteps \fInumber\fR Specifies the degree of smoothness desired for curves: each spline will be approximated with \fInumber\fR line segments. This -option is ignored unless the \fB\-smooth\fR option is true. +option is ignored unless the \fB\-smooth\fR option is true or \fBraw\fR. .PP Polygon items are different from other items such as rectangles, ovals -and arcs in that interior points are considered to be ``inside'' a -polygon (e.g. for purposes of the \fBfind closest\fR and +and arcs in that interior points are considered to be +.QW inside +a polygon (e.g. for purposes of the \fBfind closest\fR and \fBfind overlapping\fR widget commands) even if it is not filled. For most other item types, an interior point is considered to be inside the item only if the item @@ -1550,7 +1630,8 @@ following form: \fIpathName \fBcreate rectangle \fIx1 y1 x2 y2 \fR?\fIoption value option value ...\fR? \fIpathName \fBcreate rectangle \fIcoordList\fR ?\fIoption value option value ...\fR? .CE -The arguments \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR or \fIcoordList\fR give +The arguments \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR or \fIcoordList\fR +(which must have four elements) give the coordinates of two diagonally opposite corners of the rectangle (the rectangle will include its upper and left edges but not its lower or right edges). @@ -1558,8 +1639,11 @@ After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. A rectangle item becomes the current item when the mouse +pointer is over any part that is painted or (when fully transparent) that +would be painted if both the \fB\-fill\fR and \fB\-outline\fR options were +non-empty. +.PP The following standard options are supported by rectangles: .CS \-dash @@ -1573,6 +1657,7 @@ The following standard options are supported by rectangles: \-outline \-activeoutline \-disabledoutline +\-outlineoffset \-outlinestipple \-activeoutlinestipple \-disabledoutlinestipple @@ -1599,15 +1684,17 @@ form: \fIpathName \fBcreate text \fIx y \fR?\fIoption value option value ...\fR? \fIpathName \fBcreate text \fIcoordList\fR ?\fIoption value option value ...\fR? .CE -The arguments \fIx\fR and \fIy\fR or \fIcoordList\fR specify the coordinates of a +The arguments \fIx\fR and \fIy\fR or \fIcoordList\fR (which must have two +elements) specify the coordinates of a point used to position the text on the display (see the options below for more information on how text is displayed). After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. A text item becomes the current item when the mouse pointer +is over any part of its bounding box. +.PP The following standard options are supported by text items: .CS \-fill @@ -1634,7 +1721,7 @@ This option defaults to \fBcenter\fR. \fB\-font \fIfontName\fR Specifies the font to use for the text item. \fIFontName\fR may be any string acceptable to \fBTk_GetFont\fR. -If this option isn't specified, it defaults to a system-dependent +If this option is not specified, it defaults to a system-dependent font. .TP \fB\-justify \fIhow\fR @@ -1651,6 +1738,15 @@ Newline characters cause line breaks. The characters in the item may also be changed with the \fBinsert\fR and \fBdelete\fR widget commands. This option defaults to an empty string. +.VS 8.5 +.TP +\fB\-underline \fI\fR +Specifies the integer index of a character within the text to be +underlined. 0 corresponds to the first character of the text +displayed, 1 to the next character, and so on. \-1 means that no +underline should be drawn (if the whole text item is to be underlined, +the appropriate font should be used instead). +.VE 8.5 .TP \fB\-width \fIlineLength\fR Specifies a maximum line length for the text, in any of the forms @@ -1671,15 +1767,19 @@ Window items are created with widget commands of the following form: \fIpathName \fBcreate window \fIx y \fR?\fIoption value option value ...\fR? \fIpathName \fBcreate window \fIcoordList\fR ?\fIoption value option value ...\fR? .CE -The arguments \fIx\fR and \fIy\fR or \fIcoordList\fR specify the coordinates of a +The arguments \fIx\fR and \fIy\fR or \fIcoordList\fR (which must have two +elements) specify the coordinates of a point used to position the window on the display (see the \fB\-anchor\fR option below for more information on how bitmaps are displayed). After the coordinates there may be any number of \fIoption\fR\-\fIvalue\fR pairs, each of which sets one of the configuration options for the item. These same \fIoption\fR\-\fIvalue\fR pairs may be used in \fBitemconfigure\fR widget commands to change the item's -configuration. -.br +configuration. Theoretically, a window item becomes the current item when the +mouse pointer is over any part of its bounding box, but in practice this +typically does not happen because the mouse pointer ceases to be over the +canvas at that point. +.PP The following standard options are supported by window items: .CS \-state @@ -1688,6 +1788,7 @@ The following standard options are supported by window items: The following extra options are supported for window items: .TP \fB\-anchor \fIanchorPos\fR +. \fIAnchorPos\fR tells how to position the window relative to the positioning point for the item; it may have any of the forms accepted by \fBTk_GetAnchor\fR. For example, if \fIanchorPos\fR @@ -1697,20 +1798,23 @@ its top center point is at the positioning point. This option defaults to \fBcenter\fR. .TP \fB\-height \fIpixels\fR +. Specifies the height to assign to the item's window. \fIPixels\fR may have any of the forms described in the \fBCOORDINATES\fR section above. -If this option isn't specified, or if it is specified as an empty -string, then the window is given whatever height it requests internally. +If this option is not specified, or if it is specified as zero, +then the window is given whatever height it requests internally. .TP \fB\-width \fIpixels\fR +. Specifies the width to assign to the item's window. \fIPixels\fR may have any of the forms described in the \fBCOORDINATES\fR section above. -If this option isn't specified, or if it is specified as an empty -string, then the window is given whatever width it requests internally. +If this option is not specified, or if it is specified as zero, +then the window is given whatever width it requests internally. .TP \fB\-window \fIpathName\fR +. Specifies the window to associate with this item. The window specified by \fIpathName\fR must either be a child of the canvas widget or a child of some ancestor of the canvas widget. @@ -1719,7 +1823,11 @@ the canvas widget or a child of some ancestor of the canvas widget. Note: due to restrictions in the ways that windows are managed, it is not possible to draw other graphical items (such as lines and images) on top of window items. A window item always obscures any graphics that -overlap it, regardless of their order in the display list. +overlap it, regardless of their order in the display list. Also note that +window items, unlike other canvas items, are not clipped for display by their +containing canvas's border, and are instead clipped by the parent widget of +the window specified by the \fB\-window\fR option; when the parent widget is +the canvas, this means that the window item can overlap the canvas's border. .SH "APPLICATION-DEFINED ITEM TYPES" .PP It is possible for individual applications to define new item @@ -1728,7 +1836,7 @@ See the documentation for \fBTk_CreateItemType\fR. .SH BINDINGS .PP In the current implementation, new canvases are not given any -default behavior: you'll have to execute explicit Tcl commands +default behavior: you will have to execute explicit Tcl commands to give the canvas its behavior. .SH CREDITS .PP @@ -1737,9 +1845,7 @@ Tk's canvas widget is a blatant ripoff of ideas from Joel Bartlett's environment and preceded canvases by a year or two. Its simple mechanisms for placing and animating graphical objects inspired the functions of canvases. - .SH "SEE ALSO" bind(n), font(n), image(n), scrollbar(n) - .SH KEYWORDS canvas, widget |