wm(3tk) Tk Built-In Commands wm(3tk)
______________________________________________________________________________
NAME
wm - Communicate with window manager
SYNOPSIS
wm option window ?args?
______________________________________________________________________________
DESCRIPTION
The wm command is used to interact with window managers in order to
control such things as the title for a window, its geometry, or the in-
crements in terms of which it may be resized. The wm command can take
any of a number of different forms, depending on the option argument.
All of the forms expect at least one additional argument, window, which
must be the path name of a top-level window.
The legal forms for the wm command are:
wm aspect window ?minNumer minDenom maxNumer maxDenom?
If minNumer, minDenom, maxNumer, and maxDenom are all specified,
then they will be passed to the window manager and the window
manager should use them to enforce a range of acceptable aspect
ratios for window. The aspect ratio of window (width/length)
will be constrained to lie between minNumer/minDenom and maxNu-
mer/maxDenom. If minNumer etc. are all specified as empty
strings, then any existing aspect ratio restrictions are re-
moved. If minNumer etc. are specified, then the command returns
an empty string. Otherwise, it returns a Tcl list containing
four elements, which are the current values of minNumer, minDe-
nom, maxNumer, and maxDenom (if no aspect restrictions are in
effect, then an empty string is returned).
wm attributes window
wm attributes window ?option?
wm attributes window ?option value option value...?
This subcommand returns or sets platform specific attributes as-
sociated with a window. The first form returns a list of the
platform specific flags and their values. The second form re-
turns the value for the specific option. The third form sets one
or more of the values. The values are as follows:
All platforms support the following attributes (though X11 users
should see the notes below):
-alpha Specifies the alpha transparency level of the toplevel.
It accepts a value from 0.0 (fully transparent) to 1.0
(opaque). Values outside that range will be constrained.
Where not supported, the -alpha value remains at 1.0.
-fullscreen
Places the window in a mode that takes up the entire
screen, has no borders, and covers the general use area
(i.e. Start menu and taskbar on Windows, dock and menubar
on OSX, general window decorations on X11).
-topmost
Specifies whether this is a topmost window (displays
above all other windows).
On Windows, the following attributes may be set.
-disabled
Specifies whether the window is in a disabled state.
-toolwindow
Specifies a toolwindow style window (as defined in the
MSDN).
-transparentcolor
Specifies the transparent color index of the toplevel.
It takes any color value accepted by Tk_GetColor. If the
empty string is specified (default), no transparent color
is used. This is supported on Windows 2000/XP+. Where
not supported, the -transparentcolor value remains at {}.
On Mac OS X, the following attributes may be set.
-modified
Specifies the modification state of the window (deter-
mines whether the window close widget contains the modi-
fication indicator and whether the proxy icon is drag-
gable).
-notify
Specifies process notification state (bouncing of the ap-
plication dock icon).
-titlepath
Specifies the path of the file referenced as the window
proxy icon (which can be dragged and dropped in lieu of
the file's finder icon).
-transparent
Makes the window content area transparent and turns off
the window shadow. For the transparency to be effective,
the toplevel background needs to be set to a color with
some alpha, e.g. “systemTransparent”.
On X11, the following attributes may be set. These are not sup-
ported by all window managers, and will have no effect under
older WMs.
-type Requests that the window should be interpreted by the │
window manager as being of the specified type(s). This │
may cause the window to be decorated in a different way │
or otherwise managed differently, though exactly what │
happens is entirely up to the window manager. A list of │
types may be used, in order of preference. The following │
values are mapped to constants defined in the EWMH speci- │
fication (using others is possible, but not advised): │
desktop │
indicates a desktop feature, │
dock │
indicates a dock/panel feature, │
toolbar │
indicates a toolbar window that should be acting │
on behalf of another window, as indicated with wm │
transient, │
menu │
indicates a torn-off menu that should be acting on │
behalf of another window, as indicated with wm │
transient, │
utility │
indicates a utility window (e.g., palette or tool- │
box) that should be acting on behalf of another │
window, as indicated with wm transient, │
splash │
indicates a splash screen, displayed during appli- │
cation start up, │
dialog │
indicates a general dialog window, that should be │
acting on behalf of another window, as indicated │
with wm transient, │
dropdown_menu │
indicates a menu summoned from a menu bar, which │
should usually also be set to be override-redi- │
rected (with wm overrideredirect), │
popup_menu │
indicates a popup menu, which should usually also │
be set to be override-redirected (with wm overrid- │
eredirect), │
tooltip │
indicates a tooltip window, which should usually │
also be set to be override-redirected (with wm │
overrideredirect), │
notification │
indicates a window that provides a background no- │
tification of some event, which should usually │
also be set to be override-redirected (with wm │
overrideredirect), │
combo │
indicates the drop-down list of a combobox widget, │
which should usually also be set to be override- │
redirected (with wm overrideredirect), │
dnd │
indicates a window that represents something being │
dragged, which should usually also be set to be │
override-redirected (with wm overrideredirect), │
normal │
indicates a window that has no special interpreta- │
tion. │
-zoomed
Requests that the window should be maximized. This is the
same as wm state zoomed on Windows and Mac OS X.
On X11, changes to window attributes are performed asyn-
chronously. Querying the value of an attribute returns the cur-
rent state, which will not be the same as the value most re-
cently set if the window manager has not yet processed the re-
quest or if it does not support the attribute.
wm client window ?name?
If name is specified, this command stores name (which should be
the name of the host on which the application is executing) in
window's WM_CLIENT_MACHINE property for use by the window man-
ager or session manager. The command returns an empty string in
this case. If name is not specified, the command returns the
last name set in a wm client command for window. If name is
specified as an empty string, the command deletes the
WM_CLIENT_MACHINE property from window.
wm colormapwindows window ?windowList?
This command is used to manipulate the WM_COLORMAP_WINDOWS prop-
erty, which provides information to the window managers about
windows that have private colormaps.
If windowList is not specified, the command returns a list whose
elements are the names of the windows in the WM_COLORMAP_WINDOWS
property. If windowList is specified, it consists of a list of
window path names; the command overwrites the WM_COLORMAP_WIN-
DOWS property with the given windows and returns an empty
string. The WM_COLORMAP_WINDOWS property should normally con-
tain a list of the internal windows within window whose col-
ormaps differ from their parents.
The order of the windows in the property indicates a priority
order: the window manager will attempt to install as many col-
ormaps as possible from the head of this list when window gets
the colormap focus. If window is not included among the windows
in windowList, Tk implicitly adds it at the end of the WM_COL-
ORMAP_WINDOWS property, so that its colormap is lowest in prior-
ity. If wm colormapwindows is not invoked, Tk will automati-
cally set the property for each top-level window to all the in-
ternal windows whose colormaps differ from their parents, fol-
lowed by the top-level itself; the order of the internal win-
dows is undefined. See the ICCCM documentation for more infor-
mation on the WM_COLORMAP_WINDOWS property.
wm command window ?value?
If value is specified, this command stores value in window's
WM_COMMAND property for use by the window manager or session
manager and returns an empty string. Value must have proper
list structure; the elements should contain the words of the
command used to invoke the application. If value is not speci-
fied then the command returns the last value set in a wm command
command for window. If value is specified as an empty string,
the command deletes the WM_COMMAND property from window.
wm deiconify window
Arrange for window to be displayed in normal (non-iconified)
form. This is done by mapping the window. If the window has
never been mapped then this command will not map the window, but
it will ensure that when the window is first mapped it will be
displayed in de-iconified form. On Windows, a deiconified win-
dow will also be raised and be given the focus (made the active
window). Returns an empty string.
wm focusmodel window ?active|passive?
If active or passive is supplied as an optional argument to the
command, then it specifies the focus model for window. In this
case the command returns an empty string. If no additional ar-
gument is supplied, then the command returns the current focus
model for window.
An active focus model means that window will claim the input fo-
cus for itself or its descendants, even at times when the focus
is currently in some other application. Passive means that win-
dow will never claim the focus for itself: the window manager
should give the focus to window at appropriate times. However,
once the focus has been given to window or one of its descen-
dants, the application may re-assign the focus among window's
descendants. The focus model defaults to passive, and Tk's fo-
cus command assumes a passive model of focusing.
wm forget window
The window will be unmapped from the screen and will no longer
be managed by wm. Windows created with the toplevel command
will be treated like frame windows once they are no longer man-
aged by wm, however, the -menu configuration will be remembered
and the menus will return once the widget is managed again.
wm frame window
If window has been reparented by the window manager into a deco-
rative frame, the command returns the platform specific window
identifier for the outermost frame that contains window (the
window whose parent is the root or virtual root). If window has
not been reparented by the window manager then the command re-
turns the platform specific window identifier for window.
wm geometry window ?newGeometry?
If newGeometry is specified, then the geometry of window is
changed and an empty string is returned. Otherwise the current
geometry for window is returned (this is the most recent geome-
try specified either by manual resizing or in a wm geometry com-
mand). NewGeometry has the form =widthxheight±x±y, where any of
=, widthxheight, or ±x±y may be omitted. Width and height are
positive integers specifying the desired dimensions of window.
If window is gridded (see GRIDDED GEOMETRY MANAGEMENT below)
then the dimensions are specified in grid units; otherwise they
are specified in pixel units.
X and y specify the desired location of window on the screen, in
pixels. If x is preceded by +, it specifies the number of pix-
els between the left edge of the screen and the left edge of
window's border; if preceded by - then x specifies the number
of pixels between the right edge of the screen and the right
edge of window's border. If y is preceded by + then it speci-
fies the number of pixels between the top of the screen and the
top of window's border; if y is preceded by - then it specifies
the number of pixels between the bottom of window's border and
the bottom of the screen.
If newGeometry is specified as an empty string then any existing
user-specified geometry for window is cancelled, and the window
will revert to the size requested internally by its widgets.
Note that this is related to winfo geometry, but not the same.
That can only query the geometry, and always reflects Tk's cur-
rent understanding of the actual size and location of window,
whereas wm geometry allows both setting and querying of the win-
dow manager's understanding of the size and location of the win-
dow. This can vary significantly, for example to reflect the ad-
dition of decorative elements to window such as title bars, and
window managers are not required to precisely follow the re-
quests made through this command.
wm grid window ?baseWidth baseHeight widthInc heightInc?
This command indicates that window is to be managed as a gridded
window. It also specifies the relationship between grid units
and pixel units. BaseWidth and baseHeight specify the number of
grid units corresponding to the pixel dimensions requested in-
ternally by window using Tk_GeometryRequest. WidthInc and
heightInc specify the number of pixels in each horizontal and
vertical grid unit. These four values determine a range of ac-
ceptable sizes for window, corresponding to grid-based widths
and heights that are non-negative integers. Tk will pass this
information to the window manager; during manual resizing, the
window manager will restrict the window's size to one of these
acceptable sizes.
Furthermore, during manual resizing the window manager will dis-
play the window's current size in terms of grid units rather
than pixels. If baseWidth etc. are all specified as empty
strings, then window will no longer be managed as a gridded win-
dow. If baseWidth etc. are specified then the return value is
an empty string.
Otherwise the return value is a Tcl list containing four ele-
ments corresponding to the current baseWidth, baseHeight,
widthInc, and heightInc; if window is not currently gridded,
then an empty string is returned.
Note: this command should not be needed very often, since the
Tk_SetGrid library procedure and the setGrid option provide eas-
ier access to the same functionality.
wm group window ?pathName?
If pathName is specified, it gives the path name for the leader
of a group of related windows. The window manager may use this
information, for example, to unmap all of the windows in a group
when the group's leader is iconified. PathName may be specified
as an empty string to remove window from any group association.
If pathName is specified then the command returns an empty
string; otherwise it returns the path name of window's current
group leader, or an empty string if window is not part of any
group.
wm iconbitmap window ?bitmap?
If bitmap is specified, then it names a bitmap in the standard
forms accepted by Tk (see the Tk_GetBitmap manual entry for de-
tails). This bitmap is passed to the window manager to be dis-
played in window's icon, and the command returns an empty
string. If an empty string is specified for bitmap, then any
current icon bitmap is cancelled for window. If bitmap is spec-
ified then the command returns an empty string. Otherwise it
returns the name of the current icon bitmap associated with win-
dow, or an empty string if window has no icon bitmap. On the
Windows operating system, an additional flag is supported:
wm iconbitmap window ?-default? ?image?
If the -default flag is given, the icon is applied to all
toplevel windows (existing and future) to which no other
specific icon has yet been applied. In addition to bit-
map image types, a full path specification to any file
which contains a valid Windows icon is also accepted
(usually .ico or .icr files), or any file for which the
shell has assigned an icon. Tcl will first test if the
file contains an icon, then if it has an assigned icon,
and finally, if that fails, test for a bitmap.
wm iconify window
Arrange for window to be iconified. It window has not yet been
mapped for the first time, this command will arrange for it to
appear in the iconified state when it is eventually mapped.
wm iconmask window ?bitmap?
If bitmap is specified, then it names a bitmap in the standard
forms accepted by Tk (see the Tk_GetBitmap manual entry for de-
tails). This bitmap is passed to the window manager to be used
as a mask in conjunction with the iconbitmap option: where the
mask has zeroes no icon will be displayed; where it has ones,
the bits from the icon bitmap will be displayed. If an empty
string is specified for bitmap then any current icon mask is
cancelled for window (this is equivalent to specifying a bitmap
of all ones). If bitmap is specified then the command returns
an empty string. Otherwise it returns the name of the current
icon mask associated with window, or an empty string if no mask
is in effect.
wm iconname window ?newName?
If newName is specified, then it is passed to the window man-
ager; the window manager should display newName inside the icon
associated with window. In this case an empty string is re-
turned as result. If newName is not specified then the command
returns the current icon name for window, or an empty string if
no icon name has been specified (in this case the window manager
will normally display the window's title, as specified with the
wm title command).
wm iconphoto window ?-default? image1 ?image2 ...?
Sets the titlebar icon for window based on the named photo im-
ages. If -default is specified, this is applied to all future
created toplevels as well. The data in the images is taken as a
snapshot at the time of invocation. If the images are later
changed, this is not reflected to the titlebar icons. Multiple
images are accepted to allow different images sizes (e.g., 16x16
and 32x32) to be provided. The window manager may scale provided
icons to an appropriate size.
On Windows, the images are packed into a Windows icon structure.
This will override an ico specified to wm iconbitmap, and vice
versa.
On X, the images are arranged into the _NET_WM_ICON X property,
which most modern window managers support. A wm iconbitmap may
exist simultaneously. It is recommended to use not more than 2
icons, placing the larger icon first.
On Macintosh, the first image called is loaded into an OSX-na-
tive icon format, and becomes the application icon in dialogs,
the Dock, and other contexts. At the script level the command
will accept only the first image passed in the parameters as
support for multiple sizes/resolutions on macOS is outside Tk's
scope. Developers should use the largest icon they can support
(preferably 512 pixels) to ensure smooth rendering on the Mac.
wm iconposition window ?x y?
If x and y are specified, they are passed to the window manager
as a hint about where to position the icon for window. In this
case an empty string is returned. If x and y are specified as
empty strings then any existing icon position hint is cancelled.
If neither x nor y is specified, then the command returns a Tcl
list containing two values, which are the current icon position
hints (if no hints are in effect then an empty string is re-
turned).
wm iconwindow window ?pathName?
If pathName is specified, it is the path name for a window to
use as icon for window: when window is iconified then pathName
will be mapped to serve as icon, and when window is de-iconified
then pathName will be unmapped again. If pathName is specified
as an empty string then any existing icon window association for
window will be cancelled. If the pathName argument is specified
then an empty string is returned. Otherwise the command returns
the path name of the current icon window for window, or an empty
string if there is no icon window currently specified for win-
dow. Button press events are disabled for window as long as it
is an icon window; this is needed in order to allow window man-
agers to “own” those events. Note: not all window managers sup-
port the notion of an icon window.
wm manage widget
The widget specified will become a stand alone top-level window.
The window will be decorated with the window managers title bar,
etc. Only frame, labelframe and toplevel widgets can be used
with this command. Attempting to pass any other widget type will
raise an error. Attempting to manage a toplevel widget is benign
and achieves nothing. See also GEOMETRY MANAGEMENT.
wm maxsize window ?width height?
If width and height are specified, they give the maximum permis-
sible dimensions for window. For gridded windows the dimensions
are specified in grid units; otherwise they are specified in
pixel units. The window manager will restrict the window's di-
mensions to be less than or equal to width and height. If width
and height are specified, then the command returns an empty
string. Otherwise it returns a Tcl list with two elements,
which are the maximum width and height currently in effect. The
maximum size defaults to the size of the screen. See the sec-
tions on geometry management below for more information.
wm minsize window ?width height?
If width and height are specified, they give the minimum permis-
sible dimensions for window. For gridded windows the dimensions
are specified in grid units; otherwise they are specified in
pixel units. The window manager will restrict the window's di-
mensions to be greater than or equal to width and height. If
width and height are specified, then the command returns an
empty string. Otherwise it returns a Tcl list with two ele-
ments, which are the minimum width and height currently in ef-
fect. The minimum size defaults to one pixel in each dimension.
See the sections on geometry management below for more informa-
tion.
wm overrideredirect window ?boolean?
If boolean is specified, it must have a proper boolean form and
the override-redirect flag for window is set to that value. If
boolean is not specified then 1 or 0 is returned to indicate
whether or not the override-redirect flag is currently set for
window. Setting the override-redirect flag for a window causes
it to be ignored by the window manager; among other things,
this means that the window will not be reparented from the root
window into a decorative frame and the user will not be able to
manipulate the window using the normal window manager mecha-
nisms.
Note that the override-redirect flag is only guaranteed to be
taken notice of when the window is first mapped or when mapped
after the state is changed from withdrawn to normal. Some, but
not all, platforms will take notice at additional times.
wm positionfrom window ?who?
If who is specified, it must be either program or user, or an
abbreviation of one of these two. It indicates whether window's
current position was requested by the program or by the user.
Many window managers ignore program-requested initial positions
and ask the user to manually position the window; if user is
specified then the window manager should position the window at
the given place without asking the user for assistance. If who
is specified as an empty string, then the current position
source is cancelled. If who is specified, then the command re-
turns an empty string. Otherwise it returns user or program to
indicate the source of the window's current position, or an
empty string if no source has been specified yet. Most window
managers interpret “no source” as equivalent to program. Tk
will automatically set the position source to user when a wm ge-
ometry command is invoked, unless the source has been set ex-
plicitly to program.
wm protocol window ?name? ?command?
This command is used to manage window manager protocols such as
WM_DELETE_WINDOW. Name is the name of an atom corresponding to
a window manager protocol, such as WM_DELETE_WINDOW or
WM_SAVE_YOURSELF or WM_TAKE_FOCUS. If both name and command are
specified, then command is associated with the protocol speci-
fied by name. Name will be added to window's WM_PROTOCOLS prop-
erty to tell the window manager that the application has a pro-
tocol handler for name, and command will be invoked in the fu-
ture whenever the window manager sends a message to the client
for that protocol. In this case the command returns an empty
string. If name is specified but command is not, then the cur-
rent command for name is returned, or an empty string if there
is no handler defined for name. If command is specified as an
empty string then the current handler for name is deleted and it
is removed from the WM_PROTOCOLS property on window; an empty
string is returned. Lastly, if neither name nor command is
specified, the command returns a list of all the protocols for
which handlers are currently defined for window.
Tk always defines a protocol handler for WM_DELETE_WINDOW, even
if you have not asked for one with wm protocol. If a
WM_DELETE_WINDOW message arrives when you have not defined a
handler, then Tk handles the message by destroying the window
for which it was received.
wm resizable window ?width height?
This command controls whether or not the user may interactively
resize a top-level window. If width and height are specified,
they are boolean values that determine whether the width and
height of window may be modified by the user. In this case the
command returns an empty string. If width and height are omit-
ted then the command returns a list with two 0/1 elements that
indicate whether the width and height of window are currently
resizable. By default, windows are resizable in both dimen-
sions. If resizing is disabled, then the window's size will be
the size from the most recent interactive resize or wm geometry
command. If there has been no such operation then the window's
natural size will be used.
wm sizefrom window ?who?
If who is specified, it must be either program or user, or an
abbreviation of one of these two. It indicates whether window's
current size was requested by the program or by the user. Some
window managers ignore program-requested sizes and ask the user
to manually size the window; if user is specified then the win-
dow manager should give the window its specified size without
asking the user for assistance. If who is specified as an empty
string, then the current size source is cancelled. If who is
specified, then the command returns an empty string. Otherwise
it returns user or window to indicate the source of the window's
current size, or an empty string if no source has been specified
yet. Most window managers interpret “no source” as equivalent
to program.
wm stackorder window ?isabove|isbelow window?
The stackorder command returns a list of toplevel windows in
stacking order, from lowest to highest. When a single toplevel
window is passed, the returned list recursively includes all of
the window's children that are toplevels. Only those toplevels
that are currently mapped to the screen are returned. The
stackorder command can also be used to determine if one toplevel
is positioned above or below a second toplevel. When two window
arguments separated by either isabove or isbelow are passed, a
boolean result indicates whether or not the first window is cur-
rently above or below the second window in the stacking order.
wm state window ?newstate?
If newstate is specified, the window will be set to the new
state, otherwise it returns the current state of window: either
normal, iconic, withdrawn, icon, or (Windows and Mac OS X only)
zoomed. The difference between iconic and icon is that iconic
refers to a window that has been iconified (e.g., with the wm
iconify command) while icon refers to a window whose only pur-
pose is to serve as the icon for some other window (via the wm
iconwindow command). The icon state cannot be set.
wm title window ?string?
If string is specified, then it will be passed to the window
manager for use as the title for window (the window manager
should display this string in window's title bar). In this case
the command returns an empty string. If string is not specified
then the command returns the current title for the window. The
title for a window defaults to its name.
wm transient window ?container?
If container is specified, then the window manager is informed
that window is a transient window (e.g. pull-down menu) working
on behalf of container (where container is the path name for a
top-level window). If container is specified as an empty string
then window is marked as not being a transient window any more.
Otherwise the command returns the path name of window's current
container, or an empty string if window is not currently a tran-
sient window. A transient window will mirror state changes in
the container and inherit the state of the container when ini-
tially mapped. The directed graph with an edge from each tran-
sient to its container must be acyclic. In particular, it is an
error to attempt to make a window a transient of itself. The
window manager may also decorate a transient window differently,
removing some features normally present (e.g., minimize and max-
imize buttons) though this is entirely at the discretion of the
window manager.
wm withdraw window
Arranges for window to be withdrawn from the screen. This
causes the window to be unmapped and forgotten about by the win-
dow manager. If the window has never been mapped, then this
command causes the window to be mapped in the withdrawn state.
Not all window managers appear to know how to handle windows
that are mapped in the withdrawn state. Note: it sometimes
seems to be necessary to withdraw a window and then re-map it
(e.g. with wm deiconify) to get some window managers to pay at-
tention to changes in window attributes such as group.
GEOMETRY MANAGEMENT
By default a top-level window appears on the screen in its natural
size, which is the one determined internally by its widgets and geome-
try managers. If the natural size of a top-level window changes, then
the window's size changes to match. A top-level window can be given a
size other than its natural size in two ways. First, the user can re-
size the window manually using the facilities of the window manager,
such as resize handles. Second, the application can request a particu-
lar size for a top-level window using the wm geometry command. These
two cases are handled identically by Tk; in either case, the requested
size overrides the natural size. You can return the window to its nat-
ural by invoking wm geometry with an empty geometry string.
Normally a top-level window can have any size from one pixel in each
dimension up to the size of its screen. However, you can use the wm
minsize and wm maxsize commands to limit the range of allowable sizes.
The range set by wm minsize and wm maxsize applies to all forms of re-
sizing, including the window's natural size as well as manual resizes
and the wm geometry command. You can also use the command wm resizable
to completely disable interactive resizing in one or both dimensions.
The wm manage and wm forget commands may be used to perform undocking
and docking of windows. After a widget is managed by wm manage com-
mand, all other wm subcommands may be used with the widget. Only wid-
gets created using the toplevel command may have an attached menu via
the -menu configure option. A toplevel widget may be used as a frame
and managed with any of the other geometry managers after using the wm
forget command. Any menu associated with a toplevel widget will be
hidden when managed by another geometry managers. The menus will reap-
pear once the window is managed by wm. All custom bindtags for widgets
in a subtree that have their top-level widget changed via a wm manage
or wm forget command, must be redone to adjust any top-level widget
path in the bindtags. Bindtags that have not been customized do not
have to be redone.
GRIDDED GEOMETRY MANAGEMENT
Gridded geometry management occurs when one of the widgets of an appli-
cation supports a range of useful sizes. This occurs, for example, in
a text editor where the scrollbars, menus, and other adornments are
fixed in size but the edit widget can support any number of lines of
text or characters per line. In this case, it is usually desirable to
let the user specify the number of lines or characters-per-line, either
with the wm geometry command or by interactively resizing the window.
In the case of text, and in other interesting cases also, only discrete
sizes of the window make sense, such as integral numbers of lines and
characters-per-line; arbitrary pixel sizes are not useful.
Gridded geometry management provides support for this kind of applica-
tion. Tk (and the window manager) assume that there is a grid of some
sort within the application and that the application should be resized
in terms of grid units rather than pixels. Gridded geometry management
is typically invoked by turning on the setGrid option for a widget; it
can also be invoked with the wm grid command or by calling Tk_SetGrid.
In each of these approaches the particular widget (or sometimes code in
the application as a whole) specifies the relationship between integral
grid sizes for the window and pixel sizes. To return to non-gridded
geometry management, invoke wm grid with empty argument strings.
When gridded geometry management is enabled then all the dimensions
specified in wm minsize, wm maxsize, and wm geometry commands are
treated as grid units rather than pixel units. Interactive resizing is
also carried out in even numbers of grid units rather than pixels.
BUGS
Most existing window managers appear to have bugs that affect the oper-
ation of the wm command. For example, some changes will not take ef-
fect if the window is already active: the window will have to be with-
drawn and de-iconified in order to make the change happen.
EXAMPLES
A fixed-size window that says that it is fixed-size too:
toplevel .fixed
wm title .fixed "Fixed-size Window"
wm resizable .fixed 0 0
A simple dialog-like window, centred on the screen:
# Create and arrange the dialog contents.
toplevel .msg
label .msg.l -text "This is a very simple dialog demo."
button .msg.ok -text OK -default active -command {destroy .msg}
pack .msg.ok -side bottom -fill x
pack .msg.l -expand 1 -fill both
# Now set the widget up as a centred dialog.
# But first, we need the geometry managers to finish setting
# up the interior of the dialog, for which we need to run the
# event loop with the widget hidden completely...
wm withdraw .msg
update
set x [expr {([winfo screenwidth .]-[winfo width .msg])/2}]
set y [expr {([winfo screenheight .]-[winfo height .msg])/2}]
wm geometry .msg +$x+$y
wm transient .msg .
wm title .msg "Dialog demo"
wm deiconify .msg
SEE ALSO
toplevel(3tk), winfo(3tk)
KEYWORDS
aspect ratio, deiconify, focus model, geometry, grid, group, icon,
iconify, increments, position, size, title, top-level window, units,
window manager
Tk 8.5 wm(3tk)
Generated by dwww version 1.14 on Fri Mar 28 12:38:46 CET 2025.