1Widget(3) User Contributed Perl Documentation Widget(3)
2
6 Tk::Widget - Base class of all widgets
7
9 package Tk::Whatever;
10 require Tk::Widget;
11 @ISA = qw(Tk::Widget);
12 Construct Tk::Widget 'Whatever';
13 sub Tk_cmd { \&Tk::whatever }
15 $widget->method(?arg, arg, ...?)
17
19 The Tk::Widget is an abstract base class for all Tk widgets.
20 Generic methods available to all widgets include the methods based on
22 core "winfo" mechanism and are used to retrieve information about win‐
23 dows managed by Tk. They can take any of a number of different forms,
24 depending on the method. The legal forms are:
25 $widget->appname?(newName)?
27 If newName isn't specified, this method returns the name of the
28 application (the name that may be used in send commands to communi‐
29 cate with the application). If newName is specified, then the name
30 of the application is changed to newName. If the given name is
31 already in use, then a suffix of the form `` #2'' or `` #3'' is
32 appended in order to make the name unique. The method's result is
33 the name actually chosen. newName should not start with a capital
34 letter. This will interfere with option processing, since names
35 starting with capitals are assumed to be classes; as a result, Tk
36 may not be able to find some options for the application. If sends
37 have been disabled by deleting the send command, this command will
38 reenable them and recreate the send command.
39 $widget->atom(name)
41 Returns a decimal string giving the integer identifier for the atom
42 whose name is name. If no atom exists with the name name then a
43 new one is created.
44 $widget->atomname(id)
46 Returns the textual name for the atom whose integer identifier is
47 id. This command is the inverse of the $widget->atom command. It
48 generates an error if no such atom exists.
49 $widget->bell( ?-nice? );
51 This command rings the bell on the display for $widget and returns
52 an empty string. The command uses the current bell-related set‐
53 tings for the display, which may be modified with programs such as
54 xset.
55 If -nice is not specified, this command also resets the screen
57 saver for the screen. Some screen savers will ignore this, but
58 others will reset so that the screen becomes visible again.
59 $widget->bindDump
61 This command returns a list of strings suitable for printing
62 detailing binding information for a widget. It prints a widget's
63 bindtags. For each binding tag it prints all the bindings, com‐
64 prised of the event descriptor and the callback. Callback argu‐
65 ments are printed, and Tk::Ev objects are expanded.
66 $widget->Busy?(?-recurse => 1?,-option => value?)?
68 This method configures a -cursor option for $widget and (if
69 -recurse = 1> is specified) all its descendants. The cursor to be
70 set may be passed as -cursor = cursor> or defaults to 'watch'.
71 Additional configure options are applied to $widget only. It also
72 adds a special tag 'Busy' to the bindtags of the widgets so config‐
73 ured so that KeyPress, KeyRelease, ButtonPress and ButtonRelease
74 events are ignored (with press events generating a call to bell).
75 It then acquires a local grab for $widget. The state of the wid‐
76 gets and the grab is restored by a call to $widget->Unbusy.
77 $widget->caret( ?-x => x?, ?-y => y?, ?-height => height? );
79 Sets and queries the caret location for the display of the speci‐
80 fied Tk window window. The caret is the per-display cursor loca‐
81 tion used for indicating global focus (e.g. to comply with Micro‐
82 soft Accessibility guidelines), as well as for location of the
83 over-the-spot XIM (X Input Methods) or Windows IME windows. If no
84 options are specified, the last values used for setting the caret
85 are return in option-value pair format. -x and -y represent win‐
86 dow-relative coordinates, and -height is the height of the current
87 cursor location, or the height of the specified window if none is
88 given.
89 $widget->cells
91 Returns a decimal string giving the number of cells in the color
92 map for $widget.
93 $widget->children
95 $widget->children Returns a list containing all the children of
96 $widget. The list is in stacking order, with the lowest window
97 first. Top-level windows are returned as children of their logical
98 parents.
99 $widget->class
101 Returns the class name for $widget.
102 $widget->colormapfull
104 Returns 1 if the colormap for $widget is known to be full, 0 other‐
105 wise. The colormap for a window is ``known'' to be full if the
106 last attempt to allocate a new color on that window failed and this
107 application hasn't freed any colors in the colormap since the
108 failed allocation.
109 $widget->ConfigSpecs
111 Used to perform delegated option configuration for a mega-widget.
112 Returns, in Tk::Derived::ConfigSpecs notation (see Tk::Con‐
113 figSpecs), all possible options for a widget. For example,
114 $s = $self->Scale;
116 $self->ConfigSpecs(
117 $s->ConfigSpecs,
118 .... more ConfigSpecs specifications
119 );
120 returns a hash of all Tk::Scale options, delegated to $s - e.g.
122 some representative examples:
123 -bigincrement => [$s, bigIncrement, BigIncrement, 0, 0]
125 -digits => [$s, digits, Digits, 0, 0]
126 -sliderlength => [$s, sliderLength, SliderLength, 10m, 30]
127 -troughcolor => [$s, troughColor, Background, #c3c3c3, #c3c3c3]
128 This provides an easy means of populating a mega-widget's Con‐
130 figSpecs with initializers.
131 $widget->containing(rootX,rootY)
133 Returns the window containing the point given by rootX and rootY.
134 RootX and rootY are specified in screen units (i.e. any form
135 acceptable to Tk_GetPixels) in the coordinate system of the root
136 window (if a virtual-root window manager is in use then the coordi‐
137 nate system of the virtual root window is used). If no window in
138 this application contains the point then an empty string is
139 returned. In selecting the containing window, children are given
140 higher priority than parents and among siblings the highest one in
141 the stacking order is chosen.
142 $widget->depth
144 Returns a decimal string giving the depth of $widget (number of
145 bits per pixel).
146 $widget->destroy
148 This command deletes the window related to $widget, plus all its
149 descendants. If all the MainWindows are deleted then the entire
150 application will be destroyed.
151 The perl object $widget continues to exist while references to it
153 still exist, e.g. until variable goes out of scope. However any
154 attempt to use Tk methods on the object will fail. Exists($widget)
155 will return false on such objects.
156 Note however that while a window exists for $widget the perl object
158 is maintained (due to "references" in perl/Tk internals) even
159 though original variables may have gone out of scope. (Normally
160 this is intuitive.)
161 Exists($widget)
163 Returns 1 if there exists a window for $widget, 0 if no such window
164 exists.
165 $widget->font(option?, arg, arg, ...?)
167 Create and inspect fonts. See Tk::Font for further details.
168 $widget->fpixels(number)
170 Returns a floating-point value giving the number of pixels in $wid‐
171 get corresponding to the distance given by number. Number may be
172 specified in any of the forms acceptable to Tk_GetScreenMM, such as
173 ``2.0c'' or ``1i''. The return value may be fractional; for an
174 integer value, use $widget->pixels.
175 $widget->Getimage(name)
177 Given name, look for an image file with that base name and return a
178 Tk::Image. File extensions are tried in this order: xpm, gif, ppm,
179 xbm until a valid iamge is found. If no image is found, try a
180 builtin image with that name.
181 $widget->geometry
183 Returns the geometry for $widget, in the form widthxheight+x+y.
184 All dimensions are in pixels.
185 $widget->height
187 Returns a decimal string giving $widget's height in pixels. When a
188 window is first created its height will be 1 pixel; the height
189 will eventually be changed by a geometry manager to fulfill the
190 window's needs. If you need the true height immediately after cre‐
191 ating a widget, invoke update to force the geometry manager to
192 arrange it, or use $widget->reqheight to get the window's requested
193 height instead of its actual height.
194 $widget->id
196 Returns a hexadecimal string giving a low-level platform-specific
197 identifier for $widget. On Unix platforms, this is the X window
198 identifier. Under Windows, this is the Windows HWND. On the Mac‐
199 intosh the value has no meaning outside Tk.
200 $widget->idletasks
202 One of two methods which are used to bring the application ``up to
203 date'' by entering the event loop repeated until all pending events
204 (including idle callbacks) have been processed.
205 If the idletasks method is specified, then no new events or errors
207 are processed; only idle callbacks are invoked. This causes opera‐
208 tions that are normally deferred, such as display updates and win‐
209 dow layout calculations, to be performed immediately.
210 The idletasks command is useful in scripts where changes have been
212 made to the application's state and you want those changes to
213 appear on the display immediately, rather than waiting for the
214 script to complete. Most display updates are performed as idle
215 callbacks, so idletasks will cause them to run. However, there are
216 some kinds of updates that only happen in response to events, such
217 as those triggered by window size changes; these updates will not
218 occur in idletasks.
219 $widget->interps
221 Returns a list whose members are the names of all Tcl interpreters
222 (e.g. all Tk-based applications) currently registered for a partic‐
223 ular display. The return value refers to the display of $widget.
224 $widget->ismapped
226 Returns 1 if $widget is currently mapped, 0 otherwise.
227 $widget->lower(?belowThis?)
229 If the belowThis argument is omitted then the command lowers $wid‐
230 get so that it is below all of its siblings in the stacking order
231 (it will be obscured by any siblings that overlap it and will not
232 obscure any siblings). If belowThis is specified then it must be
233 the path name of a window that is either a sibling of $widget or
234 the descendant of a sibling of $widget. In this case the lower
235 command will insert $widget into the stacking order just below
236 belowThis (or the ancestor of belowThis that is a sibling of $wid‐
237 get); this could end up either raising or lowering $widget.
238 $widget->MapWindow
240 Cause $widget to be "mapped" i.e. made visible on the display. May
241 confuse the geometry manager (pack, grid, place, ...) that thinks
242 it is managing the widget.
243 $widget->manager
245 Returns the name of the geometry manager currently responsible for
246 $widget, or an empty string if $widget isn't managed by any geome‐
247 try manager. The name is usually the name of the method for the
248 geometry manager, such as pack or place. If the geometry manager
249 is a widget, such as canvases or text, the name is the widget's
250 class command, such as canvas.
251 $widget->name
253 Returns $widget's name (i.e. its name within its parent, as opposed
254 to its full path name). The command $mainwin->name will return the
255 name of the application.
256 $widget->OnDestroy(callback);
258 OnDestroy accepts a standard perl/Tk callback. When the window
259 associated with $widget is destroyed then the callback is invoked.
260 Unlike $widget->bind('<Destroy>',...) the widgets methods are
261 still available when callback is executed, so (for example) a Text
262 widget can save its contents to a file.
263 OnDestroy was required for new after mechanism.
265 $widget->parent
267 Returns $widget's parent, or an empty string if $widget is the main
268 window of the application.
269 $widget->PathName
271 Returns the Tk path name of $widget. This is the inverse of the
272 "Widget" method. (This is an import from the C interface.)
273 $widget->pathname(id)
275 Returns an object whose X identifier is id. The identifier is
276 looked up on the display of $widget. Id must be a decimal, hexa‐
277 decimal, or octal integer and must correspond to a window in the
278 invoking application, or an error occurs which can be trapped with
279 "eval { }" or "Tk::catch { }". If the window belongs to the appli‐
280 cation, but is not an object (for example wrapper windows, HList
281 header, etc.) then "undef" is returned.
282 $widget->pixels(number)
284 Returns the number of pixels in $widget corresponding to the dis‐
285 tance given by number. Number may be specified in any of the forms
286 acceptable to Tk_GetPixels, such as ``2.0c'' or ``1i''. The result
287 is rounded to the nearest integer value; for a fractional result,
288 use $widget->fpixels.
289 $widget->pointerx
291 If the mouse pointer is on the same screen as $widget, returns the
292 pointer's x coordinate, measured in pixels in the screen's root
293 window. If a virtual root window is in use on the screen, the
294 position is measured in the virtual root. If the mouse pointer
295 isn't on the same screen as $widget then -1 is returned.
296 $widget->pointerxy
298 If the mouse pointer is on the same screen as $widget, returns a
299 list with two elements, which are the pointer's x and y coordinates
300 measured in pixels in the screen's root window. If a virtual root
301 window is in use on the screen, the position is computed in the
302 virtual root. If the mouse pointer isn't on the same screen as
303 $widget then both of the returned coordinates are -1.
304 $widget->pointery
306 If the mouse pointer is on the same screen as $widget, returns the
307 pointer's y coordinate, measured in pixels in the screen's root
308 window. If a virtual root window is in use on the screen, the
309 position is computed in the virtual root. If the mouse pointer
310 isn't on the same screen as $widget then -1 is returned.
311 $widget->raise(?aboveThis?)
313 If the aboveThis argument is omitted then the command raises $wid‐
314 get so that it is above all of its siblings in the stacking order
315 (it will not be obscured by any siblings and will obscure any sib‐
316 lings that overlap it). If aboveThis is specified then it must be
317 the path name of a window that is either a sibling of $widget or
318 the descendant of a sibling of $widget. In this case the raise
319 command will insert $widget into the stacking order just above
320 aboveThis (or the ancestor of aboveThis that is a sibling of $wid‐
321 get); this could end up either raising or lowering $widget.
322 $widget->reqheight
324 Returns a decimal string giving $widget's requested height, in pix‐
325 els. This is the value used by $widget's geometry manager to com‐
326 pute its geometry.
327 $widget->reqwidth
329 Returns a decimal string giving $widget's requested width, in pix‐
330 els. This is the value used by $widget's geometry manager to com‐
331 pute its geometry.
332 $widget->rgb(color)
334 Returns a list containing three decimal values, which are the red,
335 green, and blue intensities that correspond to color in the window
336 given by $widget. Color may be specified in any of the forms
337 acceptable for a color option.
338 $widget->rootx
340 Returns a decimal string giving the x-coordinate, in the root win‐
341 dow of the screen, of the upper-left corner of $widget's border (or
342 $widget if it has no border).
343 $widget->rooty
345 Returns a decimal string giving the y-coordinate, in the root win‐
346 dow of the screen, of the upper-left corner of $widget's border (or
347 $widget if it has no border).
348 $widget->scaling?(number)?
350 Sets and queries the current scaling factor used by Tk to convert
351 between physical units (for example, points, inches, or millime‐
352 ters) and pixels. The number argument is a floating point number
353 that specifies the number of pixels per point on $widget's display.
354 If the number argument is omitted, the current value of the scaling
355 factor is returned.
356 A ``point'' is a unit of measurement equal to 1/72 inch. A scaling
358 factor of 1.0 corresponds to 1 pixel per point, which is equivalent
359 to a standard 72 dpi monitor. A scaling factor of 1.25 would mean
360 1.25 pixels per point, which is the setting for a 90 dpi monitor;
361 setting the scaling factor to 1.25 on a 72 dpi monitor would cause
362 everything in the application to be displayed 1.25 times as large
363 as normal. The initial value for the scaling factor is set when
364 the application starts, based on properties of the installed moni‐
365 tor (as reported via the window system), but it can be changed at
366 any time. Measurements made after the scaling factor is changed
367 will use the new scaling factor, but it is undefined whether exist‐
368 ing widgets will resize themselves dynamically to accomodate the
369 new scaling factor.
370 $widget->screen
372 Returns the name of the screen associated with $widget, in the form
373 displayName.screenIndex.
374 $widget->screencells
376 Returns a decimal string giving the number of cells in the default
377 color map for $widget's screen.
378 $widget->screendepth
380 Returns a decimal string giving the depth of the root window of
381 $widget's screen (number of bits per pixel).
382 $widget->screenheight
384 Returns a decimal string giving the height of $widget's screen, in
385 pixels.
386 $widget->screenmmheight
388 Returns a decimal string giving the height of $widget's screen, in
389 millimeters.
390 $widget->screenmmwidth
392 Returns a decimal string giving the width of $widget's screen, in
393 millimeters.
394 $widget->screenvisual
396 Returns one of the following strings to indicate the default visual
397 class for $widget's screen: directcolor, grayscale, pseudocolor,
398 staticcolor, staticgray, or truecolor.
399 $widget->screenwidth
401 Returns a decimal string giving the width of $widget's screen, in
402 pixels.
403 $widget->server
405 Returns a string containing information about the server for $wid‐
406 get's display. The exact format of this string may vary from plat‐
407 form to platform. For X servers the string has the form ``Xmajor‐
408 Rminor vendor vendorVersion'' where major and minor are the version
409 and revision numbers provided by the server (e.g., X11R5), vendor
410 is the name of the vendor for the server, and vendorRelease is an
411 integer release number provided by the server.
412 $widget->toplevel
414 Returns the reference of the top-level window containing $widget.
415 $widget->Unbusy
417 Restores widget state after a call to $widget->Busy.
418 $widget->UnmapWindow
420 Cause $widget to be "unmapped" i.e. removed from the display. This
421 does for any widget what $widget->withdraw does for toplevel wid‐
422 gets. May confuse the geometry manager (pack, grid, place, ...)
423 that thinks it is managing the widget.
424 $widget->update
426 One of two methods which are used to bring the application ``up to
427 date'' by entering the event loop repeated until all pending events
428 (including idle callbacks) have been processed.
429 The update method is useful in scripts where you are performing a
431 long-running computation but you still want the application to
432 respond to events such as user interactions; if you occasionally
433 call update then user input will be processed during the next call
434 to update.
435 $widget->useinputmethods( ?boolean? )
437 Sets and queries the state of whether Tk should use XIM (X Input
438 Methods) for filtering events. The resulting state is returned.
439 XIM is used in some locales (ie: Japanese, Korean), to handle
440 special input devices. This feature is only significant on X.
441 If XIM support is not available, this will always return 0. If
442 the boolean argument is omitted, the current state is
443 returned. This is turned on by default for the main display.
444 $widget->viewable
446 Returns 1 if $widget and all of its ancestors up through the near‐
447 est toplevel window are mapped. Returns 0 if any of these windows
448 are not mapped.
449 $widget->visual
451 Returns one of the following strings to indicate the visual class
452 for $widget: directcolor, grayscale, pseudocolor, staticcolor,
453 staticgray, or truecolor.
454 $widget->visualid
456 Returns the X identifier for the visual for $widget.
457 $widget->visualsavailable(?includeids?)
459 Returns a list whose elements describe the visuals available for
460 $widget's screen. Each element consists of a visual class followed
461 by an integer depth. The class has the same form as returned by
462 $widget->visual. The depth gives the number of bits per pixel in
463 the visual. In addition, if the includeids argument is provided,
464 then the depth is followed by the X identifier for the visual.
465 $widget->vrootheight
467 Returns the height of the virtual root window associated with $wid‐
468 get if there is one; otherwise returns the height of $widget's
469 screen.
470 $widget->vrootwidth
472 Returns the width of the virtual root window associated with $wid‐
473 get if there is one; otherwise returns the width of $widget's
474 screen.
475 $widget->vrootx
477 Returns the x-offset of the virtual root window associated with
478 $widget, relative to the root window of its screen. This is nor‐
479 mally either zero or negative. Returns 0 if there is no virtual
480 root window for $widget.
481 $widget->vrooty
483 Returns the y-offset of the virtual root window associated with
484 $widget, relative to the root window of its screen. This is nor‐
485 mally either zero or negative. Returns 0 if there is no virtual
486 root window for $widget.
487 $widget->waitVariable(\$name)
489 $widget->waitVisibility
490 $widget->waitWindow
491 The tk wait methods wait for one of several things to happen, then
492 it returns without taking any other actions. The return value is
493 always an empty string. waitVariable expects a reference to a perl
494 variable and the command waits for that variable to be modified.
495 This form is typically used to wait for a user to finish interact‐
496 ing with a dialog which sets the variable as part (possibly final)
497 part of the interaction. waitVisibility waits for a change in
498 $widget's visibility state (as indicated by the arrival of a Visi‐
499 bilityNotify event). This form is typically used to wait for a
500 newly-created window to appear on the screen before taking some
501 action. waitWindow waits for $widget to be destroyed. This form
502 is typically used to wait for a user to finish interacting with a
503 dialog box before using the result of that interaction. Note that
504 creating and destroying the window each time a dialog is required
505 makes code modular but imposes overhead which can be avoided by
506 withdrawing the window instead and using waitVisibility.
507 While the tk wait methods are waiting they processes events in the
509 normal fashion, so the application will continue to respond to user
510 interactions. If an event handler invokes tkwait again, the nested
511 call to tkwait must complete before the outer call can complete.
512 $widget->Walk(proc?, arg, ...?)
514 Traverse a widget hierarchy starting at $widget while executing the
515 subroutine proc to every visited widget. The arguments arg, ...
516 are supplied to the subroutine.
517 $widget->Widget(pathname)
519 Returns the widget reference for the given Tk path name, or "undef"
520 if the path name does not match a Tk widget. This is the inverse of
521 the "PathName" method. (This is an import from the C interface.)
522 $widget->width
524 Returns a decimal string giving $widget's width in pixels. When a
525 window is first created its width will be 1 pixel; the width will
526 eventually be changed by a geometry manager to fulfill the window's
527 needs. If you need the true width immediately after creating a
528 widget, invoke update to force the geometry manager to arrange it,
529 or use $widget->reqwidth to get the window's requested width
530 instead of its actual width.
531 $widget->windowingsystem
533 Returns the current Tk windowing system, one of x11 (X11-based),
534 win32 (MS Windows), classic (Mac OS Classic), or aqua (Mac OS X
535 Aqua).
536 $widget->x
538 Returns a decimal string giving the x-coordinate, in $widget's par‐
539 ent, of the upper-left corner of $widget's border (or $widget if it
540 has no border).
541 $widget->y
543 Returns a decimal string giving the y-coordinate, in $widget's par‐
544 ent, of the upper-left corner of $widget's border (or $widget if it
545 has no border).
546
548 The above documentaion on generic methods is incomplete.
549
551 atom, children, class, geometry, height, identifier, information,
552 interpreters, mapped, parent, path name, screen, virtual root, width,
553 window
554perl v5.8.8 2008-02-05 Widget(3)