| '\" |
| '\" Copyright (c) 1992-1994 The Regents of the University of California. |
| '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. |
| '\" Copyright (c) 1997-1999 Scriptics Corporation. |
| '\" |
| '\" See the file "license.terms" for information on usage and redistribution |
| '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| '\" |
| '\" RCS: @(#) $Id: canvas.n,v 1.13 2002/08/08 04:54:01 hobbs Exp $ |
| '\" |
| '\" The definitions below are for supplemental macros used in Tcl/Tk |
| '\" manual entries. |
| '\" |
| '\" .AP type name in/out ?indent? |
| '\" Start paragraph describing an argument to a library procedure. |
| '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| '\" or "in/out" to describe whether procedure reads or modifies arg, |
| '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| '\" needed; use .AS below instead) |
| '\" |
| '\" .AS ?type? ?name? |
| '\" Give maximum sizes of arguments for setting tab stops. Type and |
| '\" name are examples of largest possible arguments that will be passed |
| '\" to .AP later. If args are omitted, default tab stops are used. |
| '\" |
| '\" .BS |
| '\" Start box enclosure. From here until next .BE, everything will be |
| '\" enclosed in one large box. |
| '\" |
| '\" .BE |
| '\" End of box enclosure. |
| '\" |
| '\" .CS |
| '\" Begin code excerpt. |
| '\" |
| '\" .CE |
| '\" End code excerpt. |
| '\" |
| '\" .VS ?version? ?br? |
| '\" Begin vertical sidebar, for use in marking newly-changed parts |
| '\" of man pages. The first argument is ignored and used for recording |
| '\" the version when the .VS was added, so that the sidebars can be |
| '\" found and removed when they reach a certain age. If another argument |
| '\" is present, then a line break is forced before starting the sidebar. |
| '\" |
| '\" .VE |
| '\" End of vertical sidebar. |
| '\" |
| '\" .DS |
| '\" Begin an indented unfilled display. |
| '\" |
| '\" .DE |
| '\" End of indented unfilled display. |
| '\" |
| '\" .SO |
| '\" Start of list of standard options for a Tk widget. The |
| '\" options follow on successive lines, in four columns separated |
| '\" by tabs. |
| '\" |
| '\" .SE |
| '\" End of list of standard options for a Tk widget. |
| '\" |
| '\" .OP cmdName dbName dbClass |
| '\" Start of description of a specific option. cmdName gives the |
| '\" option's name as specified in the class command, dbName gives |
| '\" the option's name in the option database, and dbClass gives |
| '\" the option's class in the option database. |
| '\" |
| '\" .UL arg1 arg2 |
| '\" Print arg1 underlined, then print arg2 normally. |
| '\" |
| '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| '\" |
| '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| .if t .wh -1.3i ^B |
| .nr ^l \n(.l |
| .ad b |
| '\" # Start an argument description |
| .de AP |
| .ie !"\\$4"" .TP \\$4 |
| .el \{\ |
| . ie !"\\$2"" .TP \\n()Cu |
| . el .TP 15 |
| .\} |
| .ta \\n()Au \\n()Bu |
| .ie !"\\$3"" \{\ |
| \&\\$1 \\fI\\$2\\fP (\\$3) |
| .\".b |
| .\} |
| .el \{\ |
| .br |
| .ie !"\\$2"" \{\ |
| \&\\$1 \\fI\\$2\\fP |
| .\} |
| .el \{\ |
| \&\\fI\\$1\\fP |
| .\} |
| .\} |
| .. |
| '\" # define tabbing values for .AP |
| .de AS |
| .nr )A 10n |
| .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
| .nr )B \\n()Au+15n |
| .\" |
| .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n |
| .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| .. |
| .AS Tcl_Interp Tcl_CreateInterp in/out |
| '\" # BS - start boxed text |
| '\" # ^y = starting y location |
| '\" # ^b = 1 |
| .de BS |
| .br |
| .mk ^y |
| .nr ^b 1u |
| .if n .nf |
| .if n .ti 0 |
| .if n \l'\\n(.lu\(ul' |
| .if n .fi |
| .. |
| '\" # BE - end boxed text (draw box now) |
| .de BE |
| .nf |
| .ti 0 |
| .mk ^t |
| .ie n \l'\\n(^lu\(ul' |
| .el \{\ |
| .\" Draw four-sided box normally, but don't draw top of |
| .\" box if the box started on an earlier page. |
| .ie !\\n(^b-1 \{\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .el \}\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .\} |
| .fi |
| .br |
| .nr ^b 0 |
| .. |
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| '\" # ^Y = starting y location |
| '\" # ^v = 1 (for troff; for nroff this doesn't matter) |
| .de VS |
| .if !"\\$2"" .br |
| .mk ^Y |
| .ie n 'mc \s12\(br\s0 |
| .el .nr ^v 1u |
| .. |
| '\" # VE - end of vertical sidebar |
| .de VE |
| .ie n 'mc |
| .el \{\ |
| .ev 2 |
| .nf |
| .ti 0 |
| .mk ^t |
| \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| .sp -1 |
| .fi |
| .ev |
| .\} |
| .nr ^v 0 |
| .. |
| '\" # Special macro to handle page bottom: finish off current |
| '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| '\" # page bottom macro. |
| .de ^B |
| .ev 2 |
| 'ti 0 |
| 'nf |
| .mk ^t |
| .if \\n(^b \{\ |
| .\" Draw three-sided box if this is the box's first page, |
| .\" draw two sides but no top otherwise. |
| .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .\} |
| .if \\n(^v \{\ |
| .nr ^x \\n(^tu+1v-\\n(^Yu |
| \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
| .\} |
| .bp |
| 'fi |
| .ev |
| .if \\n(^b \{\ |
| .mk ^y |
| .nr ^b 2 |
| .\} |
| .if \\n(^v \{\ |
| .mk ^Y |
| .\} |
| .. |
| '\" # DS - begin display |
| .de DS |
| .RS |
| .nf |
| .sp |
| .. |
| '\" # DE - end display |
| .de DE |
| .fi |
| .RE |
| .sp |
| .. |
| '\" # SO - start of list of standard options |
| .de SO |
| .SH "STANDARD OPTIONS" |
| .LP |
| .nf |
| .ta 5.5c 11c |
| .ft B |
| .. |
| '\" # SE - end of list of standard options |
| .de SE |
| .fi |
| .ft R |
| .LP |
| See the \\fBoptions\\fR manual entry for details on the standard options. |
| .. |
| '\" # OP - start of full description for a single option |
| .de OP |
| .LP |
| .nf |
| .ta 4c |
| Command-Line Name: \\fB\\$1\\fR |
| Database Name: \\fB\\$2\\fR |
| Database Class: \\fB\\$3\\fR |
| .fi |
| .IP |
| .. |
| '\" # CS - begin code excerpt |
| .de CS |
| .RS |
| .nf |
| .ta .25i .5i .75i 1i |
| .. |
| '\" # CE - end code excerpt |
| .de CE |
| .fi |
| .RE |
| .. |
| .de UL |
| \\$1\l'|0\(ul'\\$2 |
| .. |
| .TH canvas n 8.3 Tk "Tk Built-In Commands" |
| .BS |
| '\" Note: do not modify the .SH NAME line immediately below! |
| .SH NAME |
| 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 |
| .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. |
| .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 |
| \fBscrollRegion\fR argument. |
| Defaults to true, which means that the view will |
| be constrained within the scroll region. |
| .OP \-height height Height |
| 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. |
| .OP \-scrollregion scrollRegion ScrollRegion |
| Specifies a list with four 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. |
| .OP \-state state State |
| Modifies the default state of the canvas where \fIstate\fR may be set to |
| one of: \fBnormal\fR, \fBdisabled\fR, or \fBhidden\fR. Individual canvas |
| objects all have their own state option which may override the default |
| state. Many options can take separate specifications such that the |
| appearance of the item can be different in different situations. The |
| options that start with \fBactive\fR control the appearence when the mouse |
| pointer is over it, while the option starting with \fBdisabled\fR controls |
| the appearence when the state is disabled. Canvas items which are |
| \fBdisabled\fR will not react to canvas bindings. |
| .OP \-width width width |
| 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. |
| .OP \-xscrollincrement xScrollIncrement ScrollIncrement |
| 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 \fBxScrollIncrement\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 \fBxScrollIncrement\fR. If the value of |
| this option is less than or equal to zero, then horizontal scrolling |
| is unconstrained. |
| .OP \-yscrollincrement yScrollIncrement ScrollIncrement |
| 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 \fByScrollIncrement\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 \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 |
| by the \fIpathName\fR argument) and makes it into a canvas widget. |
| Additional options, described above, may be specified on the |
| command line or in the option database |
| to configure aspects of the canvas such as its colors and 3-D relief. |
| The \fBcanvas\fR command returns its |
| \fIpathName\fR argument. At the time this command is invoked, |
| there must not exist a window named \fIpathName\fR, but |
| \fIpathName\fR's parent must exist. |
| .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-colored) and commands may |
| be associated with items in much the same way that the \fBbind\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 behaviors defined by |
| the Tcl scripts bound to them. |
| |
| .SH "DISPLAY LIST" |
| .PP |
| 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. |
| .PP |
| Window items are an exception to the above rules. The underlying |
| window systems require them always to be drawn on top of other items. |
| In addition, the stacking order of window items |
| is not affected by any of the canvas widget commands; you must use |
| the \fBraise\fR and \fBlower\fR Tk commands instead. |
| |
| .SH "ITEM IDS AND TAGS" |
| .PP |
| 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 \fBall\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 \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. |
| If the mouse is not in the canvas widget or is not over |
| an item, then no item has the \fBcurrent\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. |
| .PP |
| \fItagOrId\fR may contain a logical expressions of |
| tags by using operators: '&&', '||', '^' '!', and parenthezised |
| subexpressions. For example: |
| .CS |
| .c find withtag {(a&&!b)||(!a&&b)} |
| .CE |
| or equivalently: |
| .CS |
| .c find withtag {a^b} |
| .CE |
| will find only those items with either "a" or "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 |
| names multiple items, then the normal behavior 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" |
| .PP |
| All coordinates related to canvases are stored as floating-point |
| numbers. |
| Coordinates and distances are specified in screen units, |
| which are floating-point numbers optionally followed |
| by one of several letters. |
| If no letter is supplied then the distance is in pixels. |
| If the letter is \fBm\fR then the distance is in millimeters on |
| 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 |
| .PP |
| 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 |
| \fBxview\fR and \fByview\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" |
| .PP |
| Text items support the notion of an \fIindex\fR for identifying |
| particular positions within the item. |
| In a similar fashion, line and polygon items support \fIindex\fR for |
| identifying, inserting and deleting subsets of their coordinates. |
| Indices are used for commands such as inserting or deleting |
| a range of characters or coordinates, 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; if you |
| define new types of text-like items, it would be advisable to |
| 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 |
| and the selection. Their indixes are supposed to be even |
| always, because coordinates always appear in pairs. |
| .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. If indexes are odd for lines and polygons, they will be |
| automatically decremented by one. |
| 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. For |
| polygons, numbers less than 0 or greater then the length |
| of the coordinate list will be adjusted by adding or substracting |
| the length until the result is between zero and the length, |
| inclusive. |
| .TP 10 |
| \fBend\fR |
| Refers to the character or coordinate just after the last one |
| in the item (same as the number of characters or coordinates |
| in the item). |
| .TP 10 |
| \fBinsert\fR |
| Refers to the character just before which the insertion cursor |
| 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. |
| .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. |
| .TP 10 |
| \fB@\fIx,y\fR |
| Refers to the character or coordinate 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 "DASH PATTERNS" |
| .PP |
| Many items support the notion of an 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 transparant. |
| .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 |
| 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} |
| .PP |
| The main difference of this syntax with the previous is that it |
| it 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 "-" |
| always as a dash regardless of the line width. |
| .PP |
| On systems which support only a limited set of dash patterns, the dash |
| pattern will be displayed as the closest dash pattern that is available. |
| For example, on Windows only the first 4 of the above examples are |
| available. The last 2 examples will be displayed identically to the first |
| one. |
| |
| .SH "WIDGET COMMAND" |
| .PP |
| The \fBcanvas\fR command creates a new Tcl command whose |
| name is \fIpathName\fR. This |
| command may be used to invoke various |
| operations on the widget. It has the following general form: |
| .CS |
| \fIpathName option \fR?\fIarg arg ...\fR? |
| .CE |
| \fIOption\fR and the \fIarg\fRs |
| determine the exact behavior of the command. |
| The following widget commands are possible for canvas widgets: |
| .TP |
| \fIpathName \fBaddtag \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\fR 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 |
| \fBabove \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 |
| \fBall\fR |
| Selects all the items in the canvas. |
| .TP |
| \fBbelow \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 |
| \fBclosest \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 |
| \fBenclosed\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 |
| \fBoverlapping\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 |
| \fBwithtag \fItagOrId\fR |
| Selects all the items given by \fItagOrId\fR. |
| .RE |
| .TP |
| \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 |
| 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 \fBbind \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 \fBbind\fR command except that |
| it operates on items in a canvas rather than entire widgets. |
| See the \fBbind\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 \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 |
| 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 |
| item, if any. Keyboard-related events are directed to the focus item, if |
| any (see the \fBfocus\fR widget command below for more on this). If a |
| virtual event is used in a binding, that binding can trigger only if the |
| virtual event is defined by an underlying mouse-related or |
| keyboard-related event. |
| .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 \fBall\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 \fBcontinue\fR command in a binding script terminates that |
| script, and a \fBbreak\fR command terminates that script |
| and skips any remaining scripts for the event, just as for the |
| \fBbind\fR command. |
| .PP |
| If bindings have been created for a canvas window using the \fBbind\fR |
| command, then they are invoked in addition to bindings created for |
| the canvas's items using the \fBbind\fR widget command. |
| The bindings for items will be invoked before any of the bindings |
| for the window as a whole. |
| .RE |
| .TP |
| \fIpathName \fBcanvasx \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 \fBcanvasy \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 \fBcget\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 \fBcanvas\fR |
| command. |
| .TP |
| \fIpathName \fBconfigure ?\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 describing all of |
| the available options for \fIpathName\fR (see \fBTk_ConfigureInfo\fR for |
| information on the format of this list). If \fIoption\fR is specified |
| with no \fIvalue\fR, then the command returns a list describing the |
| one named option (this list will be identical to the corresponding |
| sublist of the value returned if no \fIoption\fR is specified). 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 \fBcanvas\fR |
| command. |
| .TP |
| \fIpathName\fR \fBcoords \fItagOrId \fR?\fIx0 y0 ...\fR? |
| .TP |
| \fIpathName\fR \fBcoords \fItagOrId \fR?\fIcoordList\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 \fBcreate \fItype x y \fR?\fIx y ...\fR? ?\fIoption value ...\fR? |
| .TP |
| \fIpathName \fBcreate \fItype coordList \fR?\fIoption value ...\fR? |
| Create a new item in \fIpathName\fR of type \fItype\fR. |
| The exact format of the arguments after \fBtype\fR depends |
| on \fBtype\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 \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 |
| 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. |
| If \fIlast\fR is omitted, it defaults to \fIfirst\fR. |
| This command returns an empty string. |
| .TP |
| \fIpathName \fBdelete \fR?\fItagOrId tagOrId ...\fR? |
| Delete each of the items given by each \fItagOrId\fR, and return |
| an empty string. |
| .TP |
| \fIpathName \fBdtag \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 \fBfind \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 \fBaddtag\fR command. |
| The items are returned in stacking order, with the lowest item first. |
| .TP |
| \fIpathName \fBfocus \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 \fBfocus\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 \fBfocus\fR widget |
| command with the \fBfocus\fR command to set the focus window to |
| the canvas (if it wasn't there already). |
| .RE |
| .TP |
| \fIpathName \fBgettags\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, 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 |
| 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 \fBfocus\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 \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. |
| 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 |
| of characters, or coordinates, 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 \fBinsert \fItagOrId beforeThis string\fR |
| For each of the items given by \fItagOrId\fR, if the item supports |
| text or coordinate, insertion then \fIstring\fR is inserted into the item's |
| text just before the character, or coordinate, whose index is \fIbeforeThis\fR. |
| 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 |
| for \fIbeforeThis\fR. |
| This command returns an empty string. |
| .TP |
| \fIpathName \fBitemcget\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 \fBcget\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 \fBcreate\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 \fBitemconfigure \fItagOrId\fR ?\fIoption\fR? ?\fIvalue\fR? ?\fIoption value ...\fR? |
| This command is similar to the \fBconfigure\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 no \fIoption\fR is specified, returns a list describing all of |
| the available options for the first item given by \fItagOrId\fR |
| (see \fBTk_ConfigureInfo\fR for |
| information on the format of this list). If \fIoption\fR is specified |
| with no \fIvalue\fR, then the command returns a list describing the |
| one named option (this list will be identical to the corresponding |
| sublist of the value returned if no \fIoption\fR is specified). 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 \fBcreate\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 \fBlower \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. |
| Note: this command has no effect on window items. Window items always |
| obscure other item types, and the stacking order of window items is |
| determined by the \fBraise\fR and \fBlower\fR commands, not the |
| \fBraise\fR and \fBlower\fR widget commands for canvases. |
| This command returns an empty string. |
| .TP |
| \fIpathName \fBmove \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 \fBpostscript \fR?\fIoption value option value ...\fR? |
| Generate a Postscript representation for part or all of the canvas. |
| If the \fB\-file\fR option is specified then the Postscript is written |
| to a file and an empty string is returned; otherwise the Postscript |
| is returned as the result of the command. |
| If the interpreter that owns the canvas is marked as safe, the operation |
| will fail because safe interpreters are not allowed to write files. |
| If the \fB\-channel\fR option is specified, the argument denotes the name |
| of a channel already opened for writing. The Postscript is written to |
| that channel, and the channel is left open for further writing at the end |
| of the operation. |
| The Postscript is created in Encapsulated Postscript form using |
| version 3.0 of the Document Structuring Conventions. |
| 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 |
| 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 |
| information to control the generation of Postscript. The following |
| options are supported: |
| .RS |
| .TP |
| \fB\-colormap \fIvarName\fR |
| \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''). |
| 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 |
| in \fIvarName\fR for a given color, then Tk uses the red, green, |
| and blue intensities from the X color. |
| .TP |
| \fB\-colormode \fImode\fR |
| Specifies how to output color information. \fIMode\fR must be either |
| \fBcolor\fR (for full color output), \fBgray\fR (convert all colors |
| to their gray-scale equivalents) or \fBmono\fR (convert all colors |
| 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 |
| result of the command instead of being written to a file. |
| .TP |
| \fB\-fontmap \fIvarName\fR |
| \fIVarName\fR must be the name of an array variable |
| that specifies a font mapping to use in the Postscript. |
| Each element of \fIvarName\fR must consist of a Tcl list with |
| two elements, which are the name and point size of a Postscript font. |
| When outputting Postscript commands for a particular font, Tk |
| checks to see if \fIvarName\fR contains an element with the same |
| name as the font. |
| If there is such an element, then the font information contained in |
| that element is used in the Postscript. |
| Otherwise Tk attempts to guess what Postscript font to use. |
| Tk's guesses generally only work for well-known fonts such as |
| Times and Helvetica and Courier, and only if the X font name does not |
| omit any dashes up through the point size. |
| For example, \fB\-*\-Courier\-Bold\-R\-Normal\-\-*\-120\-*\fR will work but |
| \fB*Courier\-Bold\-R\-Normal*120*\fR will not; Tk needs the dashes to |
| parse the font name). |
| .TP |
| \fB\-height \fIsize\fR |
| Specifies the height of the area of the canvas to print. |
| Defaults to the height of the canvas window. |
| .TP |
| \fB\-pageanchor \fIanchor\fR |
| Specifies which point of the printed area of the canvas should appear over |
| the positioning point on the page (which is given by the \fB\-pagex\fR |
| and \fB\-pagey\fR options). |
| For example, \fB\-pageanchor n\fR means that the top center of the |
| area of the canvas being printed (as it appears in the canvas window) |
| should be over the positioning point. Defaults to \fBcenter\fR. |
| .TP |
| \fB\-pageheight \fIsize\fR |
| Specifies that the Postscript should be scaled in both x and y so |
| that the printed area is \fIsize\fR high on the Postscript page. |
| \fISize\fR consists of a floating-point number followed by |
| \fBc\fR for centimeters, \fBi\fR for inches, \fBm\fR for millimeters, |
| or \fBp\fR or nothing for printer's points (1/72 inch). |
| Defaults to the height of the printed area on the screen. |
| If both \fB\-pageheight\fR and \fB\-pagewidth\fR are specified then |
| the scale factor from \fB\-pagewidth\fR is used (non-uniform scaling |
| is not implemented). |
| .TP |
| \fB\-pagewidth \fIsize\fR |
| Specifies that the Postscript should be scaled in both x and y so |
| that the printed area is \fIsize\fR wide on the Postscript page. |
| \fISize\fR has the same form as for \fB\-pageheight\fR. |
| Defaults to the width of the printed area on the screen. |
| If both \fB\-pageheight\fR and \fB\-pagewidth\fR are specified then |
| the scale factor from \fB\-pagewidth\fR is used (non-uniform scaling |
| is not implemented). |
| .TP |
| \fB\-pagex \fIposition\fR |
| \fIPosition\fR gives the x-coordinate of the positioning point on |
| the Postscript page, using any of the forms allowed for \fB\-pageheight\fR. |
| Used in conjunction with the \fB\-pagey\fR and \fB\-pageanchor\fR options |
| to determine where the printed area appears on the Postscript page. |
| Defaults to the center of the page. |
| .TP |
| \fB\-pagey \fIposition\fR |
| \fIPosition\fR gives the y-coordinate of the positioning point on |
| the Postscript page, using any of the forms allowed for \fB\-pageheight\fR. |
| Used in conjunction with the \fB\-pagex\fR and \fB\-pageanchor\fR options |
| to determine where the printed area appears on the Postscript page. |
| Defaults to the center of the page. |
| .TP |
| \fB\-rotate \fIboolean\fR |
| \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). |
| Defaults to non-rotated. |
| .TP |
| \fB\-width \fIsize\fR |
| Specifies the width of the area of the canvas to print. |
| Defaults to the width of the canvas window. |
| .TP |
| \fB\-x \fIposition\fR |
| Specifies the x-coordinate of the left edge of the area of the |
| canvas that is to be printed, in canvas coordinates, not window |
| coordinates. |
| Defaults to the coordinate of the left edge of the window. |
| .TP |
| \fB\-y \fIposition\fR |
| Specifies the y-coordinate of the top edge of the area of the |
| canvas that is to be printed, in canvas coordinates, not window |
| coordinates. |
| Defaults to the coordinate of the top edge of the window. |
| .RE |
| .TP |
| \fIpathName \fBraise \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. |
| Note: this command has no effect on window items. Window items always |
| obscure other item types, and the stacking order of window items is |
| determined by the \fBraise\fR and \fBlower\fR commands, not the |
| \fBraise\fR and \fBlower\fR widget commands for canvases. |
| This command returns an empty string. |
| .TP |
| \fIpathName \fBscale \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 \fBscan\fR \fIoption args\fR |
| This command is used to implement scanning on canvases. It has |
| two forms, depending on \fIoption\fR: |
| .RS |
| .TP |
| \fIpathName \fBscan mark \fIx y\fR |
| Records \fIx\fR and \fIy\fR and the canvas's current view; used |
| in conjunction with later \fBscan dragto\fR commands. |
| Typically this command is associated with a mouse button press in |
| the widget and \fIx\fR and \fIy\fR are the coordinates of the |
| mouse. It returns an empty string. |
| .TP |
| \fIpathName \fBscan dragto \fIx y ?gain?\fR. |
| This command computes the difference between its \fIx\fR and \fIy\fR |
| arguments (which are typically mouse coordinates) and the \fIx\fR and |
| \fIy\fR arguments to the last \fBscan mark\fR command for the widget. |
| It then adjusts the view by \fIgain\fR times the |
| difference in coordinates, where \fIgain\fR defaults to 10. |
| This command is typically associated |
| with mouse motion events in the widget, to produce the effect of |
| dragging the canvas at high speed through its window. The return |
| value is an empty string. |
| .RE |
| .TP |
| \fIpathName \fBselect \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 \fBselect 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 \fBselect to\fR commands. |
| If the selection isn't 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 |
| has no effect. |
| Returns an empty string. |
| .TP |
| \fIpathName \fBselect 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 \fBselect to\fR |
| commands. |
| Returns an empty string. |
| .TP |
| \fIpathName \fBselect 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 \fBselect 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 \fBselect adjust\fR |
| or \fBselect 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 \fBtype\fI tagOrId\fR |
| 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 |
| an empty string is returned. |
| .TP |
| \fIpathName \fBxview \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 \fBxview\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 \fB\-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 \fB\-xscrollcommand\fR |
| option. |
| .TP |
| \fIpathName \fBxview 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 \fBxview 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 \fBunits\fR or \fBpages\fR or an abbreviation |
| of one of these. |
| If \fIwhat\fR is \fBunits\fR, the view adjusts left or right in units |
| of the \fBxScrollIncrement\fR option, if it is greater than zero, |
| or in units of one-tenth the window's width otherwise. |
| If \fIwhat is \fBpages\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 \fByview \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 \fByview\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 \fB\-scrollregion\fR |
| option) is visible in the window. |
| These are the same values passed to scrollbars via the \fB\-yscrollcommand\fR |
| option. |
| .TP |
| \fIpathName \fByview 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 \fByview 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 \fBunits\fR or \fBpages\fR. |
| If \fIwhat\fR is \fBunits\fR, the view adjusts up or down in units |
| of the \fByScrollIncrement\fR option, if it is greater than zero, |
| or in units of one-tenth the window's height otherwise. |
| If \fIwhat\fR is \fBpages\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" |
| .PP |
| 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 \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 |
| 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" |
| .PP |
| Many items share a common set of options. These options are |
| explained here, and then referred to be each widget type for brevity. |
| .PP |
| .TP |
| \fB\-dash \fIpattern\fR |
| .TP |
| \fB\-activedash \fIpattern\fR |
| .TP |
| \fB\-disableddash \fIpattern\fR |
| 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. |
| .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 |
| in the COORDINATES section above. |
| .TP |
| \fB\-fill \fIcolor\fR |
| .TP |
| \fB\-activefill \fIcolor\fR |
| .TP |
| \fB\-disabledfill \fIcolor\fR |
| Specifies the color to be used to fill item's area. |
| in its normal, active, and disabled states, |
| \fIColor\fR may have any of the forms accepted by \fBTk_GetColor\fR. |
| If \fIcolor\fR is an empty string (the default), then |
| then the item will not be filled. |
| For the line item, it specifies the color of the line drawn. |
| For the text item, it specifies the foreground color of the text. |
| .TP |
| \fB\-outline \fIcolor\fR |
| .TP |
| \fB\-activeoutline \fIcolor\fR |
| .TP |
| \fB\-disabledoutline \fIcolor\fR |
| This option specifies the color that should be used to draw the |
| outline of the item in its normal, active and disabled states. |
| \fIColor\fR may have any of the forms accepted by \fBTk_GetColor\fR. |
| This option defaults to \fBblack\fR. If \fIcolor\fR is specified |
| as an empty string then no outline is drawn for the item. |
| .TP |
| \fB\-offset \fIoffset\fR |
| Specifies the offset of stipples. The offset value can be of the form |
| \fBx,y\fR or \fBside\fR, where side can be \fBn\fR, \fBne\fR, \fBe\fR, |
| \fBse\fR, \fBs\fR, \fBsw\fR, \fBw\fR, \fBnw\fR, or \fBcenter\fR. In the |
| 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 |
| 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. |
| .TP |
| \fB\-outlinestipple \fIbitmap\fR |
| .TP |
| \fB\-activeoutlinestipple \fIbitmap\fR |
| .TP |
| \fB\-disabledoutlinestipple \fIbitmap\fR |
| This option specifies stipple patterns that should be used to draw the |
| 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 |
| has no effect. |
| If \fIbitmap\fR is an empty string (the default), then the outline is drawn |
| in a solid fashion. |
| .TP |
| \fB\-stipple \fIbitmap\fR |
| .TP |
| \fB\-activestipple \fIbitmap\fR |
| .TP |
| \fB\-disabledstipple \fIbitmap\fR |
| This option specifies stipple patterns that should be used to fill the |
| 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 |
| has no effect. |
| If \fIbitmap\fR is an empty string (the default), then filling is done |
| in a solid fashion. |
| For the text item, it affects the actual text. |
| .TP |
| \fB\-state \fIstate\fR |
| This allows an item to override the canvas widget's global \fIstate\fR |
| option. It takes the same values: |
| \fInormal\fR, \fIdisabled\fR or \fIhidden\fR. |
| .TP |
| \fB\-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 |
| \fB\-width \fIoutlineWidth\fR |
| .TP |
| \fB\-activewidth \fIoutlineWidth\fR |
| .TP |
| \fB\-disabledwidth \fIoutlineWidth\fR |
| Specifies the width of the outline to be drawn around |
| the item's region, in its normal, active and disabled states. |
| \fIoutlineWidth\fR may be in any of the forms described in the COORDINATES |
| section above. |
| If the \fB\-outline\fR option has been specified as an empty string then |
| this option has no effect. This option defaults to 1.0. |
| For arcs, wide outlines will be drawn centered on the edges of the |
| arc's region. |
| |
| .SH "ARC ITEMS" |
| .PP |
| Items of type \fBarc\fR appear on the display as arc-shaped regions. |
| An arc is a section of an oval delimited by two angles (specified |
| by the \fB\-start\fR and \fB\-extent\fR options) and displayed in |
| one of several ways (specified by the \fB\-style\fR option). |
| Arcs are created with widget commands of the following form: |
| .CS |
| \fIpathName \fBcreate arc \fIx1 y1 x2 y2 \fR?\fIoption value option value ...\fR? |
| \fIpathName \fBcreate arc \fIcoordList\fR ?\fIoption value option value ...\fR? |
| .CE |
| The arguments \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR or \fIcoordList\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 \fBitemconfigure\fR widget commands to change the item's |
| configuration. |
| .br |
| The following standard options are supported by arcs: |
| .CS |
| \-dash |
| \-activedash |
| \-disableddash |
| \-dashoffset |
| \-fill |
| \-activefill |
| \-disabledfill |
| \-offset |
| \-outline |
| \-activeoutline |
| \-disabledoutline |
| \-outlinestipple |
| \-activeoutlinestipple |
| \-disabledoutlinestipple |
| \-stipple |
| \-activestipple |
| \-disabledstipple |
| \-state |
| \-tags |
| \-width |
| \-activewidth |
| \-disabledwidth |
| .CE |
| The following extra options are supported for arcs: |
| .TP |
| \fB\-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 \fB\-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 |
| \fB\-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 |
| \fB\-style \fItype\fR |
| Specifies how to draw the arc. If \fItype\fR is \fBpieslice\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 \fBchord\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. |
| If \fItype\fR is \fBarc\fR then the arc's region consists of |
| a section of the perimeter alone. |
| In this last case the \fB\-fill\fR option is ignored. |
| |
| .SH "BITMAP ITEMS" |
| .PP |
| Items of type \fBbitmap\fR appear on the display as images with |
| two colors, foreground and background. |
| Bitmaps are created with widget commands of the following form: |
| .CS |
| \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 |
| 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 |
| The following standard options are supported by bitmaps: |
| .CS |
| \-state |
| \-tags |
| .CE |
| The following extra options are supported for bitmaps: |
| .TP |
| \fB\-anchor \fIanchorPos\fR |
| \fIAnchorPos\fR tells how to position the bitmap 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 |
| is \fBcenter\fR then the bitmap is centered on the point; if |
| \fIanchorPos\fR is \fBn\fR then the bitmap will be drawn so that |
| its top center point is at the positioning point. |
| This option defaults to \fBcenter\fR. |
| .TP |
| \fB\-background \fIcolor\fR |
| .TP |
| \fB\-activebackground \fIbitmap\fR |
| .TP |
| \fB\-disabledbackground \fIbitmap\fR |
| Specifies the color to use for each of the bitmap's '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 |
| string, then nothing is displayed where the bitmap pixels are 0; this |
| produces a transparent effect. |
| .TP |
| \fB\-bitmap \fIbitmap\fR |
| .TP |
| \fB\-activebitmap \fIbitmap\fR |
| .TP |
| \fB\-disabledbitmap \fIbitmap\fR |
| Specifies the bitmaps to display in the item in its normal, active and |
| disabled states. |
| \fIBitmap\fR may have any of the forms accepted by \fBTk_GetBitmap\fR. |
| .TP |
| \fB\-foreground \fIcolor\fR |
| .TP |
| \fB\-activeforeground \fIbitmap\fR |
| .TP |
| \fB\-disabledforeground \fIbitmap\fR |
| Specifies the color to use for each of the bitmap's '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" |
| .PP |
| Items of type \fBimage\fR are used to display images on a |
| canvas. |
| Images are created with widget commands of the following form: |
| .CS |
| \fIpathName \fBcreate image \fIx y \fR?\fIoption value option value ...\fR? |
| \fIpathName \fBcreate image \fIcoordList\fR ?\fIoption value option value ...\fR? |
| .CE |
| The arguments \fIx\fR and \fIy\fR or \fIcoordList\fR specify the coordinates of a |
| point used to position the image on the display (see the \fB\-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 \fBitemconfigure\fR widget commands to change the item's |
| configuration. |
| .br |
| The following standard options are supported by images: |
| .CS |
| \-state |
| \-tags |
| .CE |
| The following extra options are supported for images: |
| .TP |
| \fB\-anchor \fIanchorPos\fR |
| \fIAnchorPos\fR tells how to position the image 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 |
| is \fBcenter\fR then the image is centered on the point; if |
| \fIanchorPos\fR is \fBn\fR then the image will be drawn so that |
| its top center point is at the positioning point. |
| This option defaults to \fBcenter\fR. |
| .TP |
| \fB\-image \fIname\fR |
| .TP |
| \fB\-activeimage \fIname\fR |
| .TP |
| \fB\-disabledimage \fIname\fR |
| Specifies the name of the images to display in the item in is normal, |
| active and disabled states. |
| This image must have been created previously with the |
| \fBimage create\fR command. |
| |
| .SH "LINE ITEMS" |
| .PP |
| Items of type \fBline\fR appear on the display as one or more connected |
| line segments or curves. |
| Line items support coordinate indexing operations using the canvas |
| widget commands: \fBdchars, index, insert.\fR |
| Lines are created with widget commands of the following form: |
| .CS |
| \fIpathName \fBcreate line \fIx1 y1... xn yn \fR?\fIoption value option value ...\fR? |
| \fIpathName \fBcreate line \fIcoordList\fR ?\fIoption value option value ...\fR? |
| .CE |
| The arguments \fIx1\fR through \fIyn\fR or \fIcoordList\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 \fBitemconfigure\fR widget commands to change the item's |
| configuration. |
| .br |
| The following standard options are supported by lines: |
| .CS |
| \-dash |
| \-activedash |
| \-disableddash |
| \-dashoffset |
| \-fill |
| \-activefill |
| \-disabledfill |
| \-stipple |
| \-activestipple |
| \-disabledstipple |
| \-state |
| \-tags |
| \-width |
| \-activewidth |
| \-disabledwidth |
| .CE |
| The following extra options are supported for lines: |
| .TP |
| \fB\-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 \fBnone\fR (for no arrowheads), |
| \fBfirst\fR (for an arrowhead at the first point of the line), |
| \fBlast\fR (for an arrowhead at the last point of the line), or |
| \fBboth\fR (for arrowheads at both ends). |
| This option defaults to \fBnone\fR. |
| .TP |
| \fB\-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 |
| \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. |
| Where arrowheads are drawn the cap style is ignored. |
| .TP |
| \fB\-joinstyle \fIstyle\fR |
| 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 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 |
| \fBTk_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 |
| 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 |
| 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 |
| \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. |
| |
| .SH "OVAL ITEMS" |
| .PP |
| Items of type \fBoval\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: |
| .CS |
| \fIpathName \fBcreate oval \fIx1 y1 x2 y2 \fR?\fIoption value option value ...\fR? |
| \fIpathName \fBcreate oval \fIcoordList\fR ?\fIoption value option value ...\fR? |
| .CE |
| The arguments \fIx1\fR, \fIy1\fR, \fIx2\fR, and \fIy2\fR or \fIcoordList\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 \fBitemconfigure\fR widget commands to change the item's |
| configuration. |
| .br |
| The following standard options are supported by ovals: |
| .CS |
| \-dash |
| \-activedash |
| \-disableddash |
| \-dashoffset |
| \-fill |
| \-activefill |
| \-disabledfill |
| \-offset |
| \-outline |
| \-activeoutline |
| \-disabledoutline |
| \-outlinestipple |
| \-activeoutlinestipple |
| \-disabledoutlinestipple |
| \-stipple |
| \-activestipple |
| \-disabledstipple |
| \-state |
| \-tags |
| \-width |
| \-activewidth |
| \-disabledwidth |
| .CE |
| |
| .SH "POLYGON ITEMS" |
| .PP |
| Items of type \fBpolygon\fR appear as polygonal or curved filled regions |
| on the display. |
| Polygon items support coordinate indexing operations using the canvas |
| widget commands: \fBdchars, index, insert.\fR |
| Polygons are created with widget commands of the following form: |
| .CS |
| \fIpathName \fBcreate polygon \fIx1 y1 ... xn yn \fR?\fIoption value option value ...\fR? |
| \fIpathName \fBcreate polygon \fIcoordList\fR ?\fIoption value option value ...\fR? |
| .CE |
| The arguments \fIx1\fR through \fIyn\fR or \fIcoordList\fR specify the coordinates for |
| three or more points that define a polygon. |
| The first point should not be repeated as the last to |
| close the shape; Tk will automatically close the periphery between |
| the first and last points. |
| 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 |
| The following standard options are supported by polygons: |
| .CS |
| \-dash |
| \-activedash |
| \-disableddash |
| \-dashoffset |
| \-fill |
| \-activefill |
| \-disabledfill |
| \-offset |
| \-outline |
| \-activeoutline |
| \-disabledoutline |
| \-outlinestipple |
| \-activeoutlinestipple |
| \-disabledoutlinestipple |
| \-stipple |
| \-activestipple |
| \-disabledstipple |
| \-state |
| \-tags |
| \-width |
| \-activewidth |
| \-disabledwidth |
| .CE |
| The following extra options are supported for polygons: |
| .TP |
| \fB\-joinstyle \fIstyle\fR |
| 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. |
| .TP |
| \fB\-smooth \fIboolean\fR |
| \fIBoolean\fR must have one of the forms accepted by \fBTk_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. |
| .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. |
| .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 |
| \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 |
| 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" |
| .PP |
| Items of type \fBrectangle\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: |
| .CS |
| \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 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 \fBitemconfigure\fR widget commands to change the item's |
| configuration. |
| .br |
| The following standard options are supported by rectangles: |
| .CS |
| \-dash |
| \-activedash |
| \-disableddash |
| \-dashoffset |
| \-fill |
| \-activefill |
| \-disabledfill |
| \-offset |
| \-outline |
| \-activeoutline |
| \-disabledoutline |
| \-outlinestipple |
| \-activeoutlinestipple |
| \-disabledoutlinestipple |
| \-stipple |
| \-activestipple |
| \-disabledstipple |
| \-state |
| \-tags |
| \-width |
| \-activewidth |
| \-disabledwidth |
| .CE |
| |
| .SH "TEXT ITEMS" |
| .PP |
| 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: \fBdchars\fR, |
| \fBfocus\fR, \fBicursor\fR, \fBindex\fR, \fBinsert\fR, |
| \fBselect\fR. |
| Text items are created with widget commands of the following |
| form: |
| .CS |
| \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 |
| 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 |
| The following standard options are supported by text items: |
| .CS |
| \-fill |
| \-activefill |
| \-disabledfill |
| \-stipple |
| \-activestipple |
| \-disabledstipple |
| \-state |
| \-tags |
| .CE |
| The following extra options are supported for text items: |
| .TP |
| \fB\-anchor \fIanchorPos\fR |
| \fIAnchorPos\fR tells how to position the text relative to the |
| positioning point for the text; it may have any of the forms |
| accepted by \fBTk_GetAnchor\fR. For example, if \fIanchorPos\fR |
| is \fBcenter\fR then the text is centered on the point; if |
| \fIanchorPos\fR is \fBn\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 \fBcenter\fR. |
| .TP |
| \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 |
| font. |
| .TP |
| \fB\-justify \fIhow\fR |
| Specifies how to justify the text within its bounding region. |
| \fIHow\fR must be one of the values \fBleft\fR, \fBright\fR, |
| or \fBcenter\fR. |
| This option will only matter if the text is displayed as multiple |
| lines. |
| If the option is omitted, it defaults to \fBleft\fR. |
| .TP |
| \fB\-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 |
| \fBinsert\fR and \fBdelete\fR widget commands. |
| This option defaults to an empty string. |
| .TP |
| \fB\-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" |
| .PP |
| Items of type \fBwindow\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: |
| .CS |
| \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 |
| 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 |
| The following standard options are supported by window items: |
| .CS |
| \-state |
| \-tags |
| .CE |
| 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 |
| is \fBcenter\fR then the window is centered on the point; if |
| \fIanchorPos\fR is \fBn\fR then the window will be drawn so that |
| 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 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 |
| \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 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 |
| \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. |
| \fIPathName\fR may not refer to a top-level window. |
| .PP |
| 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. |
| |
| .SH "APPLICATION-DEFINED ITEM TYPES" |
| .PP |
| It is possible for individual applications to define new item |
| types for canvas widgets using C code. |
| 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 |
| to give the canvas its behavior. |
| |
| .SH CREDITS |
| .PP |
| 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 KEYWORDS |
| canvas, widget |