ref: e81c54ba2ecc673a4d5f8aed0e9b52841fe07b0d
dir: /man/9/canvas/
.TH CANVAS 9 .SH NAME canvas \- Create and manipulate canvas widgets .SH SYNOPSIS \f5canvas\fI \fIpathName \fR?\fIoptions\fR? .SH STANDARD OPTIONS .EX -background -selectbackground -takefocus -borderwidth -selectborderwidth -xscrollcommand -relief -selectforeground -yscrollcommand .EE .SH "WIDGET-SPECIFIC OPTIONS" .TP .B -closeenough \fIdist\fP 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. .TP .B -confine \fIboolean\fP 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 \f5scrollregion\fR option. Defaults to true, which means that the view will be constrained within the scroll region. .TP .B -height \fIdist\fP Specifies a desired window height that the canvas widget should request from its geometry manager. The value may be specified in any of the forms described in the COORDINATES section below. .TP .B -scrollregion \fIlist\fP Specifies a list with four \fIdist\fP coordinates describing the left, top, right, and bottom coordinates of a rectangular region. This region is used for scrolling purposes and is considered to be the boundary of the information in the canvas. Each of the coordinates may be specified in any of the forms given in the COORDINATES section below. .TP .B -width \fIdist\fP Specifies a desired window width that the canvas widget should request from its geometry manager. The value may be specified in any of the forms described in the COORDINATES section below. .br .TP .B -xscrollincrement \fIdist\fP Specifies an increment for horizontal scrolling, in any of the usual forms permitted for screen distances. If the value of this option is greater than zero, the horizontal view in the window will be constrained so that the canvas x coordinate at the left edge of the window is always an even multiple of \f5xscrollicrement\fR; furthermore, the units for scrolling (e.g., the change in view when the left and right arrows of a scrollbar are selected) will also be \f5xscrollicrement\fR. If the value of this option is less than or equal to zero, then horizontal scrolling is unconstrained. .TP .B -yscrollincrement \fIdist\fP Specifies an increment for vertical scrolling, in any of the usual forms permitted for screen distances. If the value of this option is greater than zero, the vertical view in the window will be constrained so that the canvas y coordinate at the top edge of the window is always an even multiple of \f5yscrollicrement\fR; furthermore, the units for scrolling (e.g., the change in view when the top and bottom arrows of a scrollbar are selected) will also be \f5yscrollicrement\fR. If the value of this option is less than or equal to zero, then vertical scrolling is unconstrained. .TP .B -buffer \fIwhat\fP Specifies how much of the canvas region will be backed by an offscreen bitmap buffer. \fIWhat\fP can be one of \f5all\fP (the entire scroll region will be buffered), \f5visible\fP (only the visible area), \f5none\fP (no buffering) or \f5auto\fP (equivalent to either \f5none\fP or \f5visible\fP depending on whether the canvas is packed inside another canvas or not). .SH INTRODUCTION The \f5canvas\fR command creates a new window (given by the \fIpathName\fR argument) and makes it into a canvas widget. Additional options, described above, may be specified on the command line to configure aspects of the canvas such as its colours and 3-D relief. The \f5canvas\fR command returns its \fIpathName\fR argument. At the time this command is invoked, there must not exist a window named \fIpathName\fR. .PP Canvas widgets implement structured graphics. A canvas displays any number of \fIitems\fR, which may be things like rectangles, circles, lines, and text. Items may be manipulated (e.g. moved or re-coloured) and commands may be associated with items in much the same way that the \f5bind\fR command allows commands to be bound to widgets. For example, a particular command may be associated with the <Button-1> event so that the command is invoked whenever button 1 is pressed with the mouse cursor over an item. This means that items in a canvas can have behaviours defined by the Tk scripts bound to them. .SH "DISPLAY LIST" 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. 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 display list. .SH "ITEM IDS AND TAGS" Items in a canvas widget may be named in either of two ways: by id or by tag. Each item has a unique identifying number which is assigned to that item when it is created. The id of an item never changes and id numbers are never re-used within the lifetime of a canvas widget. .PP 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. 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''. .PP The tag \f5all\fR is implicitly associated with every item in the canvas; it may be used to invoke operations on all the items in the canvas. .PP The tag \f5current\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. If the mouse is not in the canvas widget or is not over an item, then no item has the \f5current\fR tag. .PP When specifying items in canvas widget commands, if the specifier is an integer then it is assumed to refer to the single item with that id. If the specifier is not an integer, then it is assumed to refer to all of the items in the canvas that have a tag matching the specifier. The symbol \fItagOrId\fR is used below to indicate that an argument specifies either an id that selects a single item or a tag that selects zero or more items. Some widget commands only operate on a single item at a time; if \fItagOrId\fR is specified in a way that names multiple items, then the normal behaviour is for the command to use the first (lowest) of these items in the display list that is suitable for the command. Exceptions are noted in the widget command descriptions below. .SH COORDINATES All coordinates related to canvases are stored as fixed-point numbers. Coordinates and distances are specified as documented in the .I dist section of .IR types (9). .SH TRANSFORMATIONS Normally the origin of the canvas coordinate system is at the upper-left corner of the window containing the canvas. It is possible to adjust the origin of the canvas coordinate system relative to the origin of the window using the \f5xview\fR and \f5yview\fR widget commands; this is typically used for scrolling. Canvases do not support scaling or rotation of the canvas coordinate system relative to the window coordinate system. .PP Individual items may be moved or scaled using widget commands described below, but they may not be rotated. .SH INDICES Text items support the notion of an \fIindex\fR for identifying particular positions within the item. Indices are used for commands such as inserting text, deleting a range of characters, and setting the insertion cursor position. An index may be specified in any of a number of ways, and different types of items may support different forms for specifying indices. Text items support the following forms for an index. 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. .TP 10 \fInumber\fR A decimal number giving the position of the desired character within the text item. 0 refers to the first character, 1 to the next character, and so on. A number less than 0 is treated as if it were zero, and a number greater than the length of the text item is treated as if it were equal to the length of the text item. .TP 10 \f5end\fR Refers to the character just after the last one in the item (same as the number of characters in the item). .TP 10 \f5insert\fR Refers to the character just before which the insertion cursor is drawn in this item. .TP 10 \f5sel.first\fR Refers to the first selected character in the item. If the selection isn't in this item then this form is illegal. .TP 10 \f5sel.last\fR Refers to the last selected character in the item. If the selection isn't in this item then this form is illegal. .TP 10 \f5@\fIx,y\fR Refers to the character at the point given by \fIx\fR and \fIy\fR, where \fIx\fR and \fIy\fR are specified in the coordinate system of the canvas. If \fIx\fR and \fIy\fR lie outside the coordinates covered by the text item, then they refer to the first or last character in the line that is closest to the given point. .SH "WIDGET COMMAND" The \f5canvas\fR command creates a new Tk command whose name is \fIpathName\fR. This command may be used to invoke various operations on the widget. It has the following general form: .RS .EX \fIpathName option \fR?\fIarg arg ...\fR? .EE .RE \fIOption\fR and the \fIarg\fRs determine the exact behaviour of the command. The following widget commands are possible for canvas widgets: .TP \fIpathName \f5addtag \fItag searchSpec \fR?\fIarg arg ...\fR? 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. It is possible that no items will satisfy the constraints given by \fIsearchSpec and \fIarg\fRs, in which case the command has no effect. This command returns an empty string as result. \fISearchSpec\fR and \fIarg\fR's may take any of the following forms: .RS .TP \f5above \fItagOrId\fR Selects the item just after (above) the one given by \fItagOrId\fR in the display list. If \fItagOrId\fR denotes more than one item, then the last (topmost) of these items in the display list is used. .TP \f5all\fR Selects all the items in the canvas. .TP \f5below \fItagOrId\fR Selects the item just before (below) the one given by \fItagOrId\fR in the display list. If \fItagOrId\fR denotes more than one item, then the first (lowest) of these items in the display list is used. .TP \f5closest \fIx y \fR?\fIhalo\fR? ?\fIstart\fR? Selects the item closest to the point given by \fIx\fR and \fIy\fR. If more than one item is at the same closest distance (e.g. two items overlap the point), then the top-most of these items (the last one in the display list) is used. If \fIhalo\fR is specified, then it must be a non-negative value. Any item closer than \fIhalo\fR to the point is considered to overlap it. The \fIstart\fR argument may be used to step circularly through all the closest items. If \fIstart\fR is specified, it names an item using a tag or id (if by tag, it selects the first item in the display list with the given tag). Instead of selecting the topmost closest item, this form will select the topmost closest item that is below \fIstart\fR in the display list; if no such item exists, then the selection behaves as if the \fIstart\fR argument had not been specified. .TP \f5enclosed\fR \fIx1\fR \fIy1\fR \fIx2\fR \fIy2\fR Selects all the items completely enclosed within the rectangular region given by \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR. \fIX1\fR must be no greater then \fIx2\fR and \fIy1\fR must be no greater than \fIy2\fR. .TP \f5overlapping\fR \fIx1\fR \fIy1\fR \fIx2\fR \fIy2\fR Selects all the items that overlap or are enclosed within the rectangular region given by \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR. \fIX1\fR must be no greater then \fIx2\fR and \fIy1\fR must be no greater than \fIy2\fR. .TP \f5withtag \fItagOrId\fR Selects all the items given by \fItagOrId\fR. .RE .TP \fIpathName \f5bbox \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 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. The return value may overestimate the actual bounding box by a few pixels. If no items match any of the \fItagOrId\fR arguments or if the matching items have empty bounding boxes (i.e. they have nothing to display) then an empty string is returned. .TP \fIpathName \f5bind \fItagOrId\fR ?\fIsequence\fR? ?\fIcommand\fR? This command associates \fIcommand\fR with all the items given by \fItagOrId\fR such that whenever the event sequence given by \fIsequence\fR occurs for one of the items the command will be invoked. This widget command is similar to the \f5bind\fR command except that it operates on items in a canvas rather than entire widgets. See the \f5bind\fR manual entry for complete details 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). 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 if there is no such binding). If both \fIcommand\fR and \fIsequence\fR are omitted then the command returns a list of all the sequences for which bindings have been defined for \fItagOrId\fR. .RS .PP The only events for which bindings may be specified are those related to the mouse and keyboard, such as \f5Enter\fR, \f5Leave\fR, \f5ButtonPress\fR, \f5Motion\fR, and \f5KeyPress\fR. The handling of events in canvases uses the current item defined in ITEM IDS AND TAGS above. \f5Enter\fR and \f5Leave\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 \f5Enter\fR and \f5Leave\fR events for windows. Mouse-related events are directed to the current item, if any. Keyboard-related events are directed to the focus item, if any (see the \f5focus\fR widget command below for more on this). .PP It is possible for multiple bindings to match a particular event. This could occur, for example, if one binding is associated with the item's id and another is associated with one of the item's tags. When this occurs, all of the matching bindings are invoked. A binding associated with the \f5all\fR tag is invoked first, followed by one binding for each of the item's tags (in order), followed by a binding associated with the item's id. If there are multiple matching bindings for a single tag, then only the most specific binding is invoked. A \f5continue\fR command in a binding script terminates that script, and a \f5break\fR command terminates that script and skips any remaining scripts for the event, just as for the \f5bind\fR command. .PP If bindings have been created for a canvas window using the \f5bind\fR command, then they are invoked in addition to bindings created for the canvas's items using the \f5bind\fR widget command. The bindings for items will be invoked before any of the bindings for the window as a whole. .RE .TP \fIpathName \f5canvasx \fIscreenx\fR ?\fIgridspacing\fR? Given a window x-coordinate in the canvas \fIscreenx\fR, this command returns the canvas x-coordinate that is displayed at that location. If \fIgridspacing\fR is specified, then the canvas coordinate is rounded to the nearest multiple of \fIgridspacing\fR units. .TP \fIpathName \f5canvasy \fIscreeny\fR ?\fIgridspacing\fR? Given a window y-coordinate in the canvas \fIscreeny\fR this command returns the canvas y-coordinate that is displayed at that location. If \fIgridspacing\fR is specified, then the canvas coordinate is rounded to the nearest multiple of \fIgridspacing\fR units. .TP \fIpathName \f5cget\fR \fIoption\fR Returns the current value of the configuration option given by \fIoption\fR. \fIOption\fR may have any of the values accepted by the \f5canvas\fR command. .TP \fIpathName \f5configure ?\fIoption\fR? ?\fIvalue\fR? ?\fIoption value ...\fR? Query or modify the configuration options of the widget. If no \fIoption\fR is specified, returns a list of all of the available options for \fIpathName\fR. If one or more \fIoption-value\fR pairs are specified, then the command modifies the given widget option(s) to have the given value(s); in this case the command returns an empty string. \fIOption\fR may have any of the values accepted by the \f5canvas\fR command. .TP \fIpathName\fR \f5coords \fItagOrId \fR?\fIx0 y0 ...\fR? Query or modify the coordinates that define an item. If no coordinates are specified, this command returns a list whose elements are the coordinates of the item named by \fItagOrId\fR. If coordinates are specified, then they replace the current coordinates for the named item. If \fItagOrId\fR refers to multiple items, then the first one in the display list is used. .TP \fIpathName \f5create \fItype x y \fR?\fIx y ...\fR? ?\fIoption value ...\fR? Create a new item in \fIpathName\fR of type \fItype\fR. The exact format of the arguments after \f5type\fR depends on \f5type\fR, but usually they consist of the coordinates for one or more points, followed by specifications for zero or more item options. See the subsections on individual item types below for more on the syntax of this command. This command returns the id for the new item. .TP \fIpathName \f5dchars \fItagOrId first \fR?\fIlast\fR? For each item given by \fItagOrId\fR, delete the characters in the range given by \fIfirst\fR and \fIlast\fR, inclusive. If some of the items given by \fItagOrId\fR don't support text operations, then they are ignored. \fIFirst\fR and \fIlast\fR are indices of characters within the item(s) as described in INDICES above. If \fIlast\fR is omitted, it defaults to \fIfirst\fR. This command returns an empty string. .TP \fIpathName \f5delete \fR?\fItagOrId tagOrId ...\fR? Delete each of the items given by each \fItagOrId\fR, and return an empty string. .TP \fIpathName \f5dtag \fItagOrId \fR?\fItagToDelete\fR? 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 the item is unaffected by the command. If \fItagToDelete\fR is omitted then it defaults to \fItagOrId\fR. This command returns an empty string. .TP \fIpathName \f5find \fIsearchCommand \fR?\fIarg arg ...\fR? This command returns a list consisting of all the items that meet the constraints specified by \fIsearchCommand\fR and \fIarg\fR's. \fISearchCommand\fR and \fIargs\fR have any of the forms accepted by the \f5addtag\fR command. If \fIsearchCommand\fR is \f5enclosed\fR, \f5overlapping\fR, or \f5all\fR, the items are returned in display-list order, i.e. bottommost first. .TP \fIpathName \f5focus \fR?\fItagOrId\fR? Set the keyboard focus for the canvas widget to the item given by \fItagOrId\fR. 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 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 id for the item that currently has the focus, or an empty string if no item has the focus. .RS .PP Once the focus has been set to an item, the item will display 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 \f5focus\fR command) are totally independent: a given item doesn't 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 \f5focus\fR widget command with the \f5focus\fR command to set the focus window to the canvas (if it wasn't there already). .RE .TP \fIpathName \f5gettags\fR \fItagOrId\fR 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, then an error is returned. If the item contains no tags, then an empty string is returned. .TP \fIpathName \f5grab\fR \fIwhat\fR \fItagOrId\fR Does for canvas widgets what \fIgrab\fR(9) does for normal tk widgets: mouse events will only be delivered to \fItagOrId\fR. If \fItagOrId\fR refers to more than one item, then the first such item in the display list is grabbed. \fIWhat\fR is as described in .IR grab (9). .PP Note that the canvas grab item, as set by this command, and the tk grab item, as set by .IR grab (9) are totally independent; a canvas item doesn't actually grab the mouse unless a) the canvas itself has grabbed the mouse or b) the mouse events are being delivered to the canvas as a matter of course. .TP \fIpathName \f5icursor \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 an insertion cursor then this command has no effect on them. See INDICES 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 \f5focus\fR, below), but the cursor position may be set even when the item doesn't have the focus. This command returns an empty string. .TP \fIpathName \f5index \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. The return value is guaranteed to lie between 0 and the number of characters within the item, inclusive. If \fItagOrId\fR refers to multiple items, then the index is processed in the first of these items that supports indexing operations (in display list order). .TP \fIpathName \f5insert \fItagOrId beforeThis string\fR For each of the items given by \fItagOrId\fR, if the item supports text insertion then \fIstring\fR is inserted into the item's text just before the character whose index is \fIbeforeThis\fR. See INDICES above for information about the forms allowed for \fIbeforeThis\fR. This command returns an empty string. .TP \fIpathName \f5itemcget\fR \fItagOrId\fR \fIoption\fR Returns the current value of the configuration option for the item given by \fItagOrId\fR whose name is \fIoption\fR. This command is similar to the \f5cget\fR widget command except that it applies to a particular item rather than the widget as a whole. \fIOption\fR may have any of the values accepted by the \f5create\fR widget command when the item was created. If \fItagOrId\fR is a tag that refers to more than one item, the first (lowest) such item is used. .TP \fIpathName \f5itemconfigure \fItagOrId\fR ?\fIoption\fR? ?\fIvalue\fR? ?\fIoption value ...\fR? This command is similar to the \f5configure\fR widget command except that it modifies item-specific options for the items given by \fItagOrId\fR instead of modifying options for the overall canvas widget. If one or more \fIoption-value\fR pairs are specified, then the command modifies the given widget option(s) to have the given value(s) in each of the items given by \fItagOrId\fR; in this case the command returns an empty string. The \fIoption\fRs and \fIvalue\fRs are the same as those permissible in the \f5create\fR widget command when the item(s) were created; see the sections describing individual item types below for details on the legal options. .TP \fIpathName \f5lower \fItagOrId \fR?\fIbelowThis\fR? Move all of the items given by \fItagOrId\fR to a new position in the display list just before the item given by \fIbelowThis\fR. If \fItagOrId\fR refers to more than one item then all are moved but the relative order of the moved items will not be changed. \fIBelowThis\fR is a tag or id; if it refers to more than one item then the first (lowest) of these items in the display list is used as the destination location for the moved items. This command returns an empty string. .TP \fIpathName \f5move \fItagOrId xAmount yAmount\fR Move each of the items given by \fItagOrId\fR in the canvas coordinate space by adding \fIxAmount\fR to the x-coordinate of each point associated with the item and \fIyAmount\fR to the y-coordinate of each point associated with the item. This command returns an empty string. .TP \fIpathName \f5raise \fItagOrId \fR?\fIaboveThis\fR? Move all of the items given by \fItagOrId\fR to a new position in the display list just after the item given by \fIaboveThis\fR. If \fItagOrId\fR refers to more than one item then all are moved but the relative order of the moved items will not be changed. \fIAboveThis\fR is a tag or id; if it refers to more than one item then the last (topmost) of these items in the display list is used as the destination location for the moved items. This command returns an empty string. .TP \fIpathName \f5scale \fItagOrId xOrigin yOrigin xScale yScale\fR Rescale all of the items given by \fItagOrId\fR in canvas coordinate space. \fIXOrigin\fR and \fIyOrigin\fR identify the origin for the scaling operation and \fIxScale\fR and \fIyScale\fR identify the scale factors for x- and y-coordinates, respectively (a scale factor of 1.0 implies no change to that coordinate). For each of the points defining each item, the x-coordinate is adjusted to change the distance from \fIxOrigin\fR by a factor of \fIxScale\fR. Similarly, each y-coordinate is adjusted to change the distance from \fIyOrigin\fR by a factor of \fIyScale\fR. This command returns an empty string. .TP \fIpathName \f5screenx \fIcanvasx\fR Given an x-coordinate \fIcanvasx\fR in the canvas, this command returns the equivalent screen x-coordinate. .TP \fIpathName \f5screeny \fIcanvasy\fR Given an x-coordinate \fIcanvasy\fR in the canvas, this command returns the equivalent screen y-coordinate. .TP \fIpathName \f5see \fIx1 y1\fR ?\fIx2 y2\fR? Adjusts the view in the window such that, if possible the point [\fIx1\fR, \fIy1\fR] (and, if given, the point [\fIx2\fR, \fIy2\fR]) are made visible. .TP \fIpathName \f5select \fIoption\fR ?\fItagOrId arg\fR? Manipulates the selection in one of several ways, depending on \fIoption\fR. The command may take any of the forms described below. In all of the descriptions below, \fItagOrId\fR must refer to 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. .RS .TP \fIpathName \f5select adjust \fItagOrId index\fR Locate the end of the selection in \fItagOrId\fR nearest to the character given by \fIindex\fR, and adjust that 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 \f5select to\fR commands. If the selection isn't currently in \fItagOrId\fR then this command behaves the same as the \f5select to\fR widget command. Returns an empty string. .TP \fIpathName \f5select clear\fR Clear the selection if it is in this widget. If the selection isn't in this widget then the command has no effect. Returns an empty string. .TP \fIpathName \f5select from \fItagOrId index\fR 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 the fixed end of the selection for future \f5select to\fR commands. Returns an empty string. .TP \fIpathName \f5select item\fR Returns the id of the selected item, if the selection is in an item in this canvas. If the selection is not in this canvas then an empty string is returned. .TP \fIpathName \f5select to \fItagOrId index\fR Set the selection to consist of those characters of \fItagOrId\fR between the selection anchor point and \fIindex\fR. The new selection will include the character given by \fIindex\fR; 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 \f5select adjust\fR or \f5select from\fR command for this widget. If the selection anchor point for the widget isn't currently in \fItagOrId\fR, then it is set to the same character given by \fIindex\fR. Returns an empty string. .RE .TP \fIpathName \f5type\fI tagOrId\fR Returns the type of the item given by \fItagOrId\fR, such as \f5rectangle\fR or \f5text\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 an empty string is returned. .TP \fIpathName \f5xview \fR?\fIargs\fR? This command is used to query and change the horizontal position of the information displayed in the canvas's window. It can take any of the following forms: .RS .TP \fIpathName \f5xview\fR Returns a list containing two elements. Each element is a real fraction between 0 and 1; together they describe the horizontal span that is visible in the window. For example, if the first element is .2 and the second element is .6, 20% of the canvas's area (as defined by the \f5-scrollregion\fR option) is off-screen to the left, the middle 40% is visible in the window, and 40% of the canvas is off-screen to the right. These are the same values passed to scrollbars via the \f5-xscrollcommand\fR option. .TP \fIpathName \f5xview moveto\fI fraction\fR Adjusts the view in the window so that \fIfraction\fR of the total width of the canvas is off-screen to the left. \fIFraction\fR must be a fraction between 0 and 1. .TP \fIpathName \f5xview scroll \fInumber what\fR This command shifts the view in the window left or right according to \fInumber\fR and \fIwhat\fR. \fINumber\fR must be an integer. \fIWhat\fR must be either \f5units\fR or \f5pages\fR. If \fIwhat\fR is \f5units\fR, the view adjusts left or right in units of the \f5xscrollicrement\fR option, if it is greater than zero, or in units of one-tenth the window's width otherwise. If \fIwhat is \f5pages\fR then the view adjusts in units of nine-tenths the window's width. If \fInumber\fR is negative then information farther to the left becomes visible; if it is positive then information farther to the right becomes visible. .RE .TP \fIpathName \f5yview \fI?args\fR? This command is used to query and change the vertical position of the information displayed in the canvas's window. It can take any of the following forms: .RS .TP \fIpathName \f5yview\fR Returns a list containing two elements. Each element is a real fraction between 0 and 1; together they describe the vertical span that is visible in the window. For example, if the first element is .6 and the second element is 1.0, the lowest 40% of the canvas's area (as defined by the \f5-scrollregion\fR option) is visible in the window. These are the same values passed to scrollbars via the \f5-yscrollcommand\fR option. .TP \fIpathName \f5yview moveto\fI fraction\fR Adjusts the view in the window so that \fIfraction\fR of the canvas's area is off-screen to the top. \fIFraction\fR is a fraction between 0 and 1. .TP \fIpathName \f5yview scroll \fInumber what\fR This command adjusts the view in the window up or down according to \fInumber\fR and \fIwhat\fR. \fINumber\fR must be an integer. \fIWhat\fR must be either \f5units\fR or \f5pages\fR. If \fIwhat\fR is \f5units\fR, the view adjusts up or down in units of the \f5yscrollicrement\fR option, if it is greater than zero, or in units of one-tenth the window's height otherwise. If \fIwhat\fR is \f5pages\fR then the view adjusts in units of nine-tenths the window's height. If \fInumber\fR is negative then higher information becomes visible; if it is positive then lower information becomes visible. .RE .SH "OVERVIEW OF ITEM TYPES" The sections below describe the various types of items supported by canvas widgets. Each item type is characterized by two things: first, the form of the \f5create\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 \f5create\fR and \f5itemconfigure\fR widget commands. Most items don't support indexing or selection or the commands related to them, such as \f5index\fR and \f5insert\fR. Where items do support these facilities, it is noted explicitly in the descriptions below (at present, only text items provide this support). .SH "ARC ITEMS" Items of type \f5arc\fR appear on the display as arc-shaped regions. An arc is a section of an oval delimited by two angles (specified by the \f5-start\fR and \f5-extent\fR options) and displayed in one of several ways (specified by the \f5-style\fR option). Arcs are created with widget commands of the following form: .RS .EX \fIpathName \f5create arc \fIx1 y1 x2 y2 \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR give the coordinates of two diagonally opposite corners of a rectangular region enclosing the oval that defines the arc. 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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for arcs: .TP \f5-extent \fIdegrees\fR 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 \f5-start\fR option. \fIDegrees\fR may be negative. If it is greater than 360 or less than -360, then \fIdegrees\fR modulo 360 is used as the extent. .TP \f5-fill \fIcolour\fR Fill the region of the arc with \fIcolour\fR. If \fIcolour\fR is an empty string (the default), then the arc will not be filled. .TP \f5-outline \fIcolour\fR \fIColour\fR specifies a colour to use for drawing the arc's outline. This option defaults to \f5black\fR. If \fIcolour\fR is specified as an empty string then no outline is drawn for the arc. .TP \f5-start \fIdegrees\fR Specifies the beginning of the angular range occupied by the arc. \fIDegrees\fR is given in units of degrees measured counter-clockwise from the 3-o'clock position; it may be either positive or negative. .TP \f5-stipple \fIbitmap\fR Indicates that the arc should be filled in a stipple pattern; \fIbitmap\fR specifies the stipple pattern to use. If the \f5-fill\fR option hasn't 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. The results are undefined if \fIbitmap\fR is not a 1-bit image. .TP \f5-style \fItype\fR Specifies how to draw the arc. If \fItype\fR is \f5pieslice\fR (the default) then the arc's region is defined by a section of the oval's perimeter plus two line segments, one between the center of the oval and each end of the perimeter section. If \fItype\fR is \f5chord\fR then the arc's region is defined by a section of the oval's perimeter plus a single line segment connecting the two end points of the perimeter section. This type is not implemented at the moment. It behaves as \f5arc\fR. If \fItype\fR is \f5arc\fR then the arc's region consists of a section of the perimeter alone. In this last case the \f5-fill\fR option is ignored. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .TP \f5-width \fIoutlineWidth\fR Specifies the width of the outline to be drawn around the arc's region, in any of the forms described in the COORDINATES section above. If the \f5-outline\fR option has been specified as an empty string then this option has no effect. Wide outlines will be drawn centered on the edges of the arc's region. This option defaults to 1.0. .SH "BITMAP ITEMS" Items of type \f5bitmap\fR appear on the display as images with two colours, foreground and background. Bitmaps are created with widget commands of the following form: .RS .EX \fIpathName \f5create bitmap \fIx y \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx\fR and \fIy\fR specify the coordinates of a point used to position the bitmap on the display (see the \f5-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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for bitmaps: .TP \f5-anchor \fIanchorPos\fR \fIAnchorPos\fR tells how to position the bitmap relative to the positioning point for the item. For example, if \fIanchorPos\fR is \f5center\fR then the bitmap is centered on the point; if \fIanchorPos\fR is \f5n\fR then the bitmap will be drawn so that its top center point is at the positioning point. This option defaults to \f5center\fR. .TP \f5-bitmap \fIbitmap\fR Specifies the bitmap to display in the item. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .SH "IMAGE ITEMS" Items of type \f5image\fR are used to display images on a canvas. Images are created with widget commands of the following form: .RS .EX \fIpathName \f5create image \fIx y \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx\fR and \fIy\fR specify the coordinates of a point used to position the image on the display (see the \f5-anchor\fR option below for more information). 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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for images: .TP \f5-anchor \fIanchorPos\fR \fIAnchorPos\fR tells how to position the image relative to the positioning point for the item. For example, if \fIanchorPos\fR is \f5center\fR then the image is centered on the point; if \fIanchorPos\fR is \f5n\fR then the image will be drawn so that its top center point is at the positioning point. This option defaults to \f5center\fR. .TP \f5-image \fIname\fR Specifies the name of the image to display in the item. This image must have been created previously with the \f5image create\fR command. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item; it may be an empty list. .SH "LINE ITEMS" Items of type \f5line\fR appear on the display as one or more connected line segments or curves. Lines are created with widget commands of the following form: .RS .EX \fIpathName \f5create line \fIx1 y1... xn yn \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx1\fR through \fIyn\fR give the coordinates for a series of two or more points that describe a series of connected line segments. 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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for lines: .TP \f5-arrow \fIwhere\fR Indicates whether or not arrowheads are to be drawn at one or both ends of the line. \fIWhere\fR must have one of the values \f5none\fR (for no arrowheads), \f5first\fR (for an arrowhead at the first point of the line), \f5last\fR (for an arrowhead at the last point of the line), or \f5both\fR (for arrowheads at both ends). This option defaults to \f5none\fR. .TP \f5-arrowshape \fIshape\fR This option indicates how to draw arrowheads. The \fIshape\fR argument must be a list with three elements, each specifying a distance in any of the forms described in the COORDINATES section above. The first element of the list gives the distance along the line from the neck of the arrowhead to its tip. 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. .TP \f5-capstyle \fIstyle\fR Specifies the ways in which caps are to be drawn at the endpoints of the line. \fIStyle\fR may one of \f5butt\fR, \f5projecting\fR, or \f5round\fR. If this option isn't specified then it defaults to \f5butt\fR. Where arrowheads are drawn the cap style is ignored. Note that the first two options currently have the same effect. .TP \f5-fill \fIcolour\fR \fIColour\fR specifies a colour to use for drawing the line. It may also be an empty string, in which case the line will be transparent. This option defaults to \f5black\fR. .TP \f5-smooth \fIboolean\fR \fIBoolean\fR indicates whether or not the line should be drawn as a curve. If so, the line is rendered as a set of Bezier 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. .TP \f5-stipple \fIbitmap\fR Indicates that the line should be filled in a stipple pattern; \fIbitmap\fR specifies the stipple pattern to use. If \fIbitmap\fR is an empty string (the default), then filling is done in a solid fashion. The results are undefined if \fIbitmap\fR is not a 1-bit image. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .TP \f5-width \fIlineWidth\fR \fILineWidth\fR specifies the width of the line, in any of the forms described in the COORDINATES section above. Wide lines will be drawn centered on the path specified by the points. If this option isn't specified then it defaults to 1.0. .SH "OVAL ITEMS" Items of type \f5oval\fR appear as circular or oval regions on the display. Each oval may have an outline, a fill, or both. Ovals are created with widget commands of the following form: .RS .EX \fIpathName \f5create oval \fIx1 y1 x2 y2 \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR give the coordinates of two diagonally opposite corners of a rectangular region enclosing the oval. The oval will include the top and left edges of the rectangle not the lower or right edges. If the region is square then the resulting oval is circular; otherwise it is elongated in shape. 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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for ovals: .TP \f5-fill \fIcolour\fR Fill the area of the oval with \fIcolour\fR. If \fIcolour\fR is an empty string (the default), then then the oval will not be filled. .TP \f5-outline \fIcolour\fR \fIColour\fR specifies a colour to use for drawing the oval's outline. This option defaults to \f5black\fR. If \fIcolour\fR is an empty string then no outline will be drawn for the oval. .TP \f5-stipple \fIbitmap\fR Indicates that the oval should be filled in a stipple pattern; \fIbitmap\fR specifies the stipple pattern to use. If the \f5-fill\fR option hasn't 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. The results are undefined if \fIbitmap\fR is not a 1-bit image. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .TP \f5-width \fIoutlineWidth\fR \fIoutlineWidth\fR specifies the width of the outline to be drawn around the oval, in any of the forms described in the COORDINATES section above. If the \f5-outline\fR option hasn't been specified then this option has no effect. Wide outlines are drawn centered on the oval path defined by \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR. This option defaults to 1.0. .SH "POLYGON ITEMS" Items of type \f5polygon\fR appear as polygonal or curved filled regions on the display. Polygons are created with widget commands of the following form: .RS .EX \fIpathName \f5create polygon \fIx1 y1 ... xn yn \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx1\fR through \fIyn\fR specify the coordinates for three or more points that define a closed polygon. The first and last points may be the same; whether they are or not, Tk will draw the polygon as a closed polygon. 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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for polygons: .TP \f5-fill \fIcolour\fR \fIColour\fR specifies a colour to use for filling the area of the polygon. If \fIcolour\fR is an empty string then the polygon will be transparent. This option defaults to the empty string (transparent). .TP \f5-outline \fIcolour\fR \fIColour\fR specifies a colour to use for drawing the polygon's outline. If \fIcolour\fR is an empty string then no outline will be drawn for the polygon. This option defaults to black. .TP \f5-smooth \fIboolean\fR \fIBoolean\fP indicates whether or not the polygon should be drawn with a curved perimeter. If so, the outline of the polygon becomes a set of Bezier 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. .TP \f5-stipple \fIbitmap\fR Indicates that the polygon should be filled in a stipple pattern; \fIbitmap\fR specifies the stipple pattern to use. If \fIbitmap\fR is an empty string (the default), then filling is done in a solid fashion. The results are undefined if \fIbitmap\fR is not a 1-bit image. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .TP \f5-winding \fItype\fR Specifies the winding rule to use when filling the polygon. \fIType\fR can be either \f5nonzero\fR (the default) or \f5odd\fR See \f5fillpoly\fR in .IR draw-image(2) for an explanation. .TP \f5-width \fIoutlineWidth\fR \fIOutlineWidth\fR specifies the width of the outline to be drawn around the polygon, in any of the forms described in the COORDINATES section above. If the \f5-outline\fR option hasn't been specified then this option has no effect. This option defaults to 1.0. .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 \f5find closest\fR and \f5find 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 is filled or if it has neither a fill nor an outline. If you would like an unfilled polygon whose interior points are not considered to be inside the polygon, use a line item instead. .SH "RECTANGLE ITEMS" Items of type \f5rectangle\fR appear as rectangular regions on the display. Each rectangle may have an outline, a fill, or both. Rectangles are created with widget commands of the following form: .RS .EX \fIpathName \f5create rectangle \fIx1 y1 x2 y2 \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR 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). 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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for rectangles: .TP \f5-fill \fIcolour\fR Fill the area of the rectangle with \fIcolour\fR. If \fIcolour\fR is an empty string (the default), then the rectangle will not be filled. .TP \f5-outline \fIcolour\fR Draw an outline around the edge of the rectangle in \fIcolour\fR. This option defaults to \f5black\fR. If \fIcolour\fR is an empty string then no outline will be drawn for the rectangle. .TP \f5-stipple \fIbitmap\fR Indicates that the rectangle should be filled in a stipple pattern; \fIbitmap\fR specifies the stipple pattern to use. If the \f5-fill\fR option hasn't 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. The results are undefined if \fIbitmap\fR is not a 1-bit image. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .TP \f5-width \fIoutlineWidth\fR \fIOutlineWidth\fR specifies the width of the outline to be drawn around the rectangle, in any of the forms described in the COORDINATES section above. If the \f5-outline\fR option hasn't been specified then this option has no effect. Wide outlines are drawn centered on the rectangular path defined by \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR. This option defaults to 1.0. .SH "TEXT ITEMS" A text item displays a string of characters on the screen in one or more lines. Text items support indexing and selection, along with the following text-related canvas widget commands: \f5dchars\fR, \f5focus\fR, \f5icursor\fR, \f5index\fR, \f5insert\fR, \f5select\fR. Text items are created with widget commands of the following form: .RS .EX \fIpathName \f5create text \fIx y \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx\fR and \fIy\fR 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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for text items: .TP \f5-anchor \fIanchorPos\fR \fIAnchorPos\fR tells how to position the text relative to the positioning point for the text. For example, if \fIanchorPos\fR is \f5center\fR then the text is centered on the point; if \fIanchorPos\fR is \f5n\fR then the text will be drawn such that the top center point of the rectangular region occupied by the text will be at the positioning point. This option defaults to \f5center\fR. .TP \f5-fill \fIcolour\fR \fIColour\fR specifies a colour to use for filling the text characters. If this option isn't specified then it defaults to \f5black\fR. .TP \f5-font \fIfont\fR Specifies the font to use for the text item. If this option isn't specified, it defaults to a system-dependent font. .TP \f5-justify \fIhow\fR Specifies how to justify the text within its bounding region. \fIHow\fR must be one of the values \f5left\fR, \f5right\fR, or \f5center\fR. This option will only matter if the text is displayed as multiple lines. If the option is omitted, it defaults to \f5left\fR. .TP \f5-stipple \fIbitmap\fR Indicates that the text should be drawn in a stippled pattern rather than solid; \fIbitmap\fR specifies the stipple pattern to use. If \fIbitmap\fR is an empty string (the default) then the text is drawn in a solid fashion. The results are undefined if \fIbitmap\fR is not a 1-bit image. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .TP \f5-text \fIstring\fR \fIString\fR specifies the characters to be displayed in the text item. Newline characters cause line breaks. The characters in the item may also be changed with the \f5insert\fR and \f5delete\fR widget commands. This option defaults to an empty string. .TP \f5-width \fIlineLength\fR Specifies a maximum line length for the text, in any of the forms described in the COORDINATES section above. If this option is zero (the default) the text is broken into lines only at newline characters. However, if this option is non-zero then any line that would be longer than \fIlineLength\fR is broken just before a space character to make the line shorter than \fIlineLength\fR; the space character is treated as if it were a newline character. .SH "WINDOW ITEMS" Items of type \f5window\fR cause a particular window to be displayed at a given position on the canvas. Window items are created with widget commands of the following form: .RS .EX \fIpathName \f5create window \fIx y \fR?\fIoption value option value ...\fR? .EE .RE The arguments \fIx\fR and \fIy\fR specify the coordinates of a point used to position the window on the display (see the \f5-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 \f5itemconfigure\fR widget commands to change the item's configuration. The following options are supported for window items: .TP \f5-anchor \fIanchorPos\fR \fIAnchorPos\fR tells how to position the window relative to the positioning point for the item. For example, if \fIanchorPos\fR is \f5center\fR then the window is centered on the point; if \fIanchorPos\fR is \f5n\fR then the window will be drawn so that its top center point is at the positioning point. This option defaults to \f5center\fR. .TP \f5-height \fIdist\fR Specifies the height to assign to the item's window. \fIDist\fR may have any of the forms described in the COORDINATES 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. .TP \f5-tags \fItagList\fR Specifies a set of tags to apply to the item. \fITagList\fR consists of a list of tag names, which replace any existing tags for the item. \fITagList\fR may be an empty list. .TP \f5-width \fIdist\fR Specifies the width to assign to the item's window. \fIDist\fR may have any of the forms described in the COORDINATES 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. .TP \f5-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. \fIPathName\fR may not refer to a top-level window. .SH BINDINGS New canvases are not given any default behaviour. Use .IR bind (2) commands to give the canvas its behaviour. .SH CREDITS Tk's canvas widget is a blatant ripoff of ideas from Joel Bartlett's \fIezd\fR program. \fIEzd\fR provides structured graphics in a Scheme 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 .IR options (9), .IR types (9)