Tk::Widget - Base class of all widgets
package Tk::Whatever; require Tk::Widget; @ISA = qw(Tk::Widget); Construct Tk::Widget Whatever; sub Tk_cmd { \&Tk::whatever }
$widget->method(?arg, arg,
...?)
The Tk::Widget is an abstract base class for all Tk widgets.
Generic methods available to all widgets include the methods based on
core winfo mechanism and are used to retrieve information
about windows managed by Tk. They can take any of a number of different
forms, depending on the method. The legal forms are:
If newName isn't specified, this method returns the name of the application (the name that may be used in send commands to communicate with the application). If newName is specified, then the name of the application is changed to newName. If the given name is already in use, then a suffix of the form `` #2'' or `` #3'' is appended in order to make the name unique. The method's result is the name actually chosen. newName should not start with a capital letter. This will interfere with option processing, since names starting with capitals are assumed to be classes; as a result, Tk may not be able to find some options for the application. If sends have been disabled by deleting the send command, this command will re-enable them and recreate the send command.
Returns a decimal string giving the integer identifier for the atom whose name is name. If no atom exists with the name name then a new one is created.
Returns the textual name for the atom whose integer identifier is
id. This command is the inverse of the
$widget->atom command. It
generates an error if no such atom exists.
This command rings the bell on the display for
$widget and returns an empty string. The command
uses the current bell-related settings for the display, which may be
modified with programs such as xset. If -nice
is not specified, this command also resets the screen saver for the
screen. Some screen savers will ignore this, but others will reset so
that the screen becomes visible again.
This command returns a list of strings suitable for printing detailing binding information for a widget. It prints a widget's bindtags. For each binding tag it prints all the bindings, comprised of the event descriptor and the callback. Callback arguments are printed, and Tk::Ev objects are expanded.
This method configures a -cursor
option for $widget and (if -recurse
= 1> is specified) all its descendants. The cursor to be set
may be passed as -cursor = cursor> or
defaults to 'watch'. Additional configure options are
applied to $widget only. It also adds a special
tag 'Busy' to the bindtags of the
widgets so configured so that KeyPress,
KeyRelease, ButtonPress and
ButtonRelease events are ignored (with press events
generating a call to bell). It then acquires a local
grab for $widget. The state of
the widgets and the grab is restored by a call to
$widget->Unbusy.
Sets and queries the caret location for the display of the specified Tk window window. The caret is the per-display cursor location used for indicating global focus (e.g. to comply with Microsoft Accessibility guidelines), as well as for location of the over-the-spot XIM (X Input Methods) or Windows IME windows. If no options are specified, the last values used for setting the caret are return in option-value pair format. -x and -y represent window-relative coordinates, and -height is the height of the current cursor location, or the height of the specified window if none is given.
Returns a decimal string giving the number of cells in the color map
for $widget.
$widget->children Returns a
list containing all the children of $widget. The list is in
stacking order, with the lowest window first. Top-level windows are
returned as children of their logical parents.
Returns the class name for $widget.
Returns 1 if the colormap for $widget is known
to be full, 0 otherwise. The colormap for a window is ``known'' to be
full if the last attempt to allocate a new color on that window failed
and this application hasn't freed any colors in the colormap since the
failed allocation.
Used to perform delegated option configuration for a mega-widget.
Returns, in Tk::Derived::ConfigSpecs notation (see Tk::ConfigSpecs), all
possible options for a widget. For example, $s = $self->Scale;
$self->ConfigSpecs( $s->ConfigSpecs, .... more ConfigSpecs
specifications ); returns a hash of all Tk::Scale options, delegated to
$s - e.g. some representative examples: -bigincrement =>
[$s, bigIncrement, BigIncrement, 0, 0] -digits => [$s, digits,
Digits, 0, 0] -sliderlength => [$s, sliderLength, SliderLength, 10m,
30] -troughcolor => [$s, troughColor, Background, #c3c3c3, #c3c3c3]
This provides an easy means of populating a mega-widget's ConfigSpecs
with initializers.
Returns the window containing the point given by rootX and rootY. RootX and rootY are specified in screen units (i.e. any form acceptable to Tk_GetPixels) in the coordinate system of the root window (if a virtual-root window manager is in use then the coordinate system of the virtual root window is used). If no window in this application contains the point then an empty string is returned. In selecting the containing window, children are given higher priority than parents and among siblings the highest one in the stacking order is chosen.
Returns a decimal string giving the depth of
$widget (number of bits per pixel).
This command deletes the window related to
$widget, plus all its descendants. If all the
MainWindows are deleted then the entire application
will be destroyed. The perl object $widget
continues to exist while references to it still exist, e.g. until
variable goes out of scope. However any attempt to use Tk methods on the
object will fail. Exists($widget)
will return false on such objects. Note however that while a window
exists for $widget the perl object is maintained
(due to references in perl/Tk internals) even though original variables
may have gone out of scope. (Normally this is intuitive.)
Returns 1 if there exists a window for $widget,
0 if no such window exists.
Create and inspect fonts. See Tk::Font for further details.
Returns a floating-point value giving the number of pixels in
$widget corresponding to the distance given by
number. Number may be specified in any of the forms
acceptable to Tk_GetScreenMM, such as ``2.0c'' or
``1i''. The return value may be fractional; for an integer value, use
$widget->pixels.
Given name, look for an image file with that base name and return a Tk::Image. File extensions are tried in this order: xpm, gif, ppm, xbm until a valid iamge is found. If no image is found, try a builtin image with that name.
Returns the geometry for $widget, in the form
widthxheight+x+y.
All dimensions are in pixels.
Returns a decimal string giving $widget's
height in pixels. When a window is first created its height will be 1
pixel; the height will eventually be changed by a geometry manager to
fulfill the window's needs. If you need the true height immediately
after creating a widget, invoke update to force the
geometry manager to arrange it, or use
$widget->reqheight to get the
window's requested height instead of its actual height.
Returns a hexadecimal string giving a low-level platform-specific
identifier for $widget. On Unix platforms, this is the X
window identifier. Under Windows, this is the Windows HWND. On the
Macintosh the value has no meaning outside Tk.
One of two methods which are used to bring the application ``up to date'' by entering the event loop repeated until all pending events (including idle callbacks) have been processed. If the idletasks method is specified, then no new events or errors are processed; only idle callbacks are invoked. This causes operations that are normally deferred, such as display updates and window layout calculations, to be performed immediately. The idletasks command is useful in scripts where changes have been made to the application's state and you want those changes to appear on the display immediately, rather than waiting for the script to complete. Most display updates are performed as idle callbacks, so idletasks will cause them to run. However, there are some kinds of updates that only happen in response to events, such as those triggered by window size changes; these updates will not occur in idletasks.
Returns a list whose members are the names of all Tcl interpreters
(e.g. all Tk-based applications) currently registered for a particular
display. The return value refers to the display of
$widget.
Returns 1 if $widget is
currently mapped, 0 otherwise.
If the belowThis argument is omitted then the command lowers
$widget so that it is below all of its siblings in the
stacking order (it will be obscured by any siblings that overlap it and
will not obscure any siblings). If belowThis is specified then
it must be the path name of a window that is either a sibling of
$widget or the descendant of a sibling of
$widget. In this case the lower command
will insert $widget into the stacking order just below
belowThis (or the ancestor of belowThis that is a
sibling of $widget); this could end up either raising or
lowering $widget.
Cause $widget to be mapped i.e. made visible on
the display. May confuse the geometry manager (pack, grid, place, ...)
that thinks it is managing the widget.
Returns the name of the geometry manager currently responsible for
$widget, or an empty string if
$widget isn't managed by any geometry manager. The
name is usually the name of the method for the geometry manager, such as
pack or place. If the geometry manager
is a widget, such as canvases or text, the name is the widget's class
command, such as canvas.
Returns $widget's name (i.e. its name within
its parent, as opposed to its full path name). The command
$mainwin->name will return the
name of the application.
OnDestroy accepts a standard perl/Tk callback. When the
window associated with $widget is destroyed then
the callback is invoked. Unlike
$widget->bind('<Destroy>',...) the
widgets methods are still available when callback is executed,
so (for example) a Text widget can save its contents to
a file. OnDestroy was required for new after
mechanism.
Returns $widget's parent, or an empty string if
$widget is the main window of the application.
Returns the Tk path name of $widget. This is
the inverse of the Widget method. (This is an import from the C
interface.)
Returns an object whose X identifier is id. The identifier
is looked up on the display of $widget.
Id must be a decimal, hexadecimal, or octal integer and must
correspond to a window in the invoking application, or an error occurs
which can be trapped with eval { } or
Tk::catch { }. If the window belongs to the application,
but is not an object (for example wrapper windows, HList header, etc.)
then undef is returned.
Returns the number of pixels in $widget
corresponding to the distance given by number. Number
may be specified in any of the forms acceptable to
Tk_GetPixels, such as ``2.0c'' or ``1i''. The result is
rounded to the nearest integer value; for a fractional result, use
$widget->fpixels.
If the mouse pointer is on the same screen as
$widget, returns the pointer's x coordinate,
measured in pixels in the screen's root window. If a virtual root window
is in use on the screen, the position is measured in the virtual root.
If the mouse pointer isn't on the same screen as
$widget then -1 is returned.
If the mouse pointer is on the same screen as
$widget, returns a list with two elements, which
are the pointer's x and y coordinates measured in pixels in the screen's
root window. If a virtual root window is in use on the screen, the
position is computed in the virtual root. If the mouse pointer isn't on
the same screen as $widget then both of the
returned coordinates are -1.
If the mouse pointer is on the same screen as
$widget, returns the pointer's y coordinate,
measured in pixels in the screen's root window. If a virtual root window
is in use on the screen, the position is computed in the virtual root.
If the mouse pointer isn't on the same screen as
$widget then -1 is returned.
If the aboveThis argument is omitted then the command raises
$widget so that it is above all of its siblings in the
stacking order (it will not be obscured by any siblings and will obscure
any siblings that overlap it). If aboveThis is specified then
it must be the path name of a window that is either a sibling of
$widget or the descendant of a sibling of
$widget. In this case the raise command
will insert $widget into the stacking order just above
aboveThis (or the ancestor of aboveThis that is a
sibling of $widget); this could end up either raising or
lowering $widget.
Returns a decimal string giving $widget's
requested height, in pixels. This is the value used by
$widget's geometry manager to compute its
geometry.
Returns a decimal string giving $widget's
requested width, in pixels. This is the value used by
$widget's geometry manager to compute its
geometry.
Returns a list containing three decimal values, which are the red,
green, and blue intensities that correspond to color in the
window given by $widget. Color may be
specified in any of the forms acceptable for a color option.
Returns a decimal string giving the x-coordinate, in the root window
of the screen, of the upper-left corner of
$widget's border (or $widget
if it has no border).
Returns a decimal string giving the y-coordinate, in the root window
of the screen, of the upper-left corner of
$widget's border (or $widget
if it has no border).
Sets and queries the current scaling factor used by Tk to convert
between physical units (for example, points, inches, or millimeters) and
pixels. The number argument is a floating point number that
specifies the number of pixels per point on $widget's
display. If the number argument is omitted, the current value
of the scaling factor is returned. A ``point'' is a unit of measurement
equal to 1/72 inch. A scaling factor of 1.0 corresponds to 1 pixel per
point, which is equivalent to a standard 72 dpi monitor. A scaling
factor of 1.25 would mean 1.25 pixels per point, which is the setting
for a 90 dpi monitor; setting the scaling factor to 1.25 on a 72 dpi
monitor would cause everything in the application to be displayed 1.25
times as large as normal. The initial value for the scaling factor is
set when the application starts, based on properties of the installed
monitor (as reported via the window system), but it can be changed at
any time. Measurements made after the scaling factor is changed will use
the new scaling factor, but it is undefined whether existing widgets
will resize themselves dynamically to accommodate the new scaling
factor.
Returns the name of the screen associated with
$widget, in the form
displayName.screenIndex.
Returns a decimal string giving the number of cells in the default
color map for $widget's screen.
Returns a decimal string giving the depth of the root window of
$widget's screen (number of bits per pixel).
Returns a decimal string giving the height of
$widget's screen, in pixels.
Returns a decimal string giving the height of
$widget's screen, in millimeters.
Returns a decimal string giving the width of
$widget's screen, in millimeters.
Returns one of the following strings to indicate the default visual
class for $widget's screen:
directcolor, grayscale,
pseudocolor, staticcolor,
staticgray, or truecolor.
Returns a decimal string giving the width of
$widget's screen, in pixels.
Returns a string containing information about the server for
$widget's display. The exact format of this string
may vary from platform to platform. For X servers the string has the
form ``XmajorRminor
vendor vendorVersion'' where major and minor are
the version and revision numbers provided by the server (e.g.,
X11R5), vendor is the name of the vendor for
the server, and vendorRelease is an integer release number
provided by the server.
Returns the reference of the top-level window containing
$widget.
Restores widget state after a call to
$widget->Busy.
Cause $widget to be unmapped i.e. removed from
the display. This does for any widget what
$widget->withdraw does for toplevel widgets.
May confuse the geometry manager (pack, grid, place, ...) that thinks it
is managing the widget.
One of two methods which are used to bring the application ``up to date'' by entering the event loop repeated until all pending events (including idle callbacks) have been processed. The update method is useful in scripts where you are performing a long-running computation but you still want the application to respond to events such as user interactions; if you occasionally call update then user input will be processed during the next call to update.
Sets and queries the state of whether Tk should use XIM (X Input Methods) for filtering events. The resulting state is returned. XIM is used in some locales (ie: Japanese, Korean), to handle special input devices. This feature is only significant on X. If XIM support is not available, this will always return 0. If the boolean argument is omitted, the current state is returned. This is turned on by default for the main display.
Returns 1 if $widget and all of its ancestors
up through the nearest toplevel window are mapped. Returns 0 if any of
these windows are not mapped.
Returns one of the following strings to indicate the visual class for
$widget: directcolor,
grayscale, pseudocolor,
staticcolor, staticgray, or
truecolor.
Returns the X identifier for the visual for $widget.
Returns a list whose elements describe the visuals available for
$widget's screen. Each element consists of a
visual class followed by an integer depth. The class has the same form
as returned by
$widget->visual. The depth
gives the number of bits per pixel in the visual. In addition, if the
includeids argument is provided, then the depth is
followed by the X identifier for the visual.
Returns the height of the virtual root window associated with
$widget if there is one; otherwise returns the
height of $widget's screen.
Returns the width of the virtual root window associated with
$widget if there is one; otherwise returns the
width of $widget's screen.
Returns the x-offset of the virtual root window associated with
$widget, relative to the root window of its
screen. This is normally either zero or negative. Returns 0 if there is
no virtual root window for $widget.
Returns the y-offset of the virtual root window associated with
$widget, relative to the root window of its
screen. This is normally either zero or negative. Returns 0 if there is
no virtual root window for $widget.
The tk wait methods wait for one of several things
to happen, then it returns without taking any other actions. The return
value is always an empty string. waitVariable expects a
reference to a perl variable and the command waits for that variable to
be modified. This form is typically used to wait for a user to finish
interacting with a dialog which sets the variable as part (possibly
final) part of the interaction. waitVisibility waits
for a change in $widget's visibility state (as
indicated by the arrival of a VisibilityNotify event). This form is
typically used to wait for a newly-created window to appear on the
screen before taking some action. waitWindow waits for
$widget to be destroyed. This form is typically
used to wait for a user to finish interacting with a dialog box before
using the result of that interaction. Note that creating and destroying
the window each time a dialog is required makes code modular but imposes
overhead which can be avoided by withdrawing the window
instead and using waitVisibility. While the tk
wait methods are waiting they processes events in the normal
fashion, so the application will continue to respond to user
interactions. If an event handler invokes tkwait again,
the nested call to tkwait must complete before the
outer call can complete.
Traverse a widget hierarchy starting at $widget
while executing the subroutine proc to every visited widget.
The arguments arg, ... are supplied to the subroutine.
Returns the widget reference for the given Tk path name, or
undef if the path name does not match a Tk widget. This is
the inverse of the PathName method. (This is an import from the C
interface.)
Returns a decimal string giving $widget's width
in pixels. When a window is first created its width will be 1 pixel; the
width will eventually be changed by a geometry manager to fulfill the
window's needs. If you need the true width immediately after creating a
widget, invoke update to force the geometry manager to
arrange it, or use
$widget->reqwidth to get the
window's requested width instead of its actual width.
Returns the current Tk windowing system, one of x11 (X11-based), win32 (MS Windows), classic (Mac OS Classic), or aqua (Mac OS X Aqua).
Returns a decimal string giving the x-coordinate, in
$widget's parent, of the upper-left corner of
$widget's border (or $widget
if it has no border).
Returns a decimal string giving the y-coordinate, in
$widget's parent, of the upper-left corner of
$widget's border (or $widget
if it has no border).
The above documentation on generic methods is incomplete.
atom, children, class, geometry, height, identifier, information, interpreters, mapped, parent, path name, screen, virtual root, width, window