### 3.25 wm ¶

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 increments 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 maxNumer/maxDenom. If minNumer etc. are all specified as empty strings, then any existing aspect ratio restrictions are removed. 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, minDenom, maxNumer, and maxDenom (if no aspect restrictions are in effect, then an empty string is returned).

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 manager or session manager. The command returns an empty string in this case. If name isn’t 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 :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 isn’t specified 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. 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 argument is supplied, then the command returns the current focus model for window. An active focus model means that window will claim the input focus for itself or its descendants, even at times when the focus is currently in some other application. Passive means that window 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 descendants, the application may re-assign the focus among window’s descendants. The focus model defaults to passive, and Tk’s focus command assumes a passive model of focussing.

wm :frame window

  If window has been reparented by the window manager into a decorative frame, the command returns the X window identifier for the outermost frame that contains window (the window whose parent is the root or virtual root). If window hasn’t been reparented by the window manager then the command returns the X 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 geometry specified either by manual resizing or in a wm :geometry command). NewGeometry has the form =width x height\(+-x\(+-y, where any of =, width x height, 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 pixels 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 specifies 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.

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 internally 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 acceptable 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 display 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 window. If baseWidth etc. are specified then the return value is an empty string. Otherwise the return value is a Tcl list containing four elements 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 easier 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 isn’t 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 details). This bitmap is passed to the window manager to be displayed 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 specified then the command returns an empty string. Otherwise it returns the name of the current icon bitmap associated with window, or an empty string if window has no icon bitmap.

wm :iconify window

  Arrange for window to be iconified. It window hasn’t 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 details). 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 manager; the window manager should display newName inside the icon associated with window. In this case an empty string is returned as result. If newName isn’t 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 :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 returned).

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 should 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 window. Note: not all window managers support the notion of an icon window.

wm :maxsize window ?width height?

  If width and height are specified, then window becomes resizable and width and height give its maximum permissible dimensions. For gridded windows the dimensions are specified in grid units; otherwise they are specified in pixel units. During manual sizing, the window manager should restrict the window’s dimensions to be less than or equal to width and height. If width and height are specified as empty strings, then the maximum size option is cancelled for window. 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; if no maximum dimensions are in effect for window then an empty string is returned. See the sections on geometry management below for more information.

wm :minsize window ?width height?

  If width and height are specified, then window becomes resizable and width and height give its minimum permissible dimensions. For gridded windows the dimensions are specified in grid units; otherwise they are specified in pixel units. During manual sizing, the window manager should restrict the window’s dimensions to be greater than or equal to width and height. If width and height are specified as empty strings, then the minimum size option is cancelled for window. 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 minimum width and height currently in effect; if no minimum dimensions are in effect for window then an empty string is returned. See the sections on geometry management below for more information.

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 mechanisms.

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 returns an empty string. Otherwise it returns user or window 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 :geometry command is invoked, unless the source has been set explicitly 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 specified by name. Name will be added to window’s WM_PROTOCOLS property to tell the window manager that the application has a protocol handler for name, and command will be invoked in the future 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 isn’t, then the current 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 haven’t asked for one with wm :protocol. If a WM_DELETE_WINDOW message arrives when you haven’t defined a handler, then Tk handles the message by destroying the window for which it was received. .RE

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 window 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 :state window

  Returns the current state of window: either normal, iconic, or withdrawn.

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 isn’t specified then the command returns the current title for the window. The title for a window defaults to its name.

wm :transient window ?master?

  If master is specified, then the window manager is informed that window is a transient window (e.g. pull-down menu) working on behalf of master (where master is the path name for a top-level window). Some window managers will use this information to manage window specially. If master is specified as an empty string then window is marked as not being a transient window any more. If master is specified, then the command returns an empty string. Otherwise the command returns the path name of window’s current master, or an empty string if window isn’t currently a transient window.

wm :withdraw window

  Arranges for window to be withdrawn from the screen. This causes the window to be unmapped and forgotten about by the window 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 attention to changes in window attributes such as group.

#### "Sources Of Geometry Information" ¶

Size-related information for top-level windows can come from three sources. First, geometry requests come from the widgets that are descendants of a top-level window. Each widget requests a particular size for itself by calling Tk_GeometryRequest. This information is passed to geometry managers, which then request large enough sizes for parent windows so that they can layout the children properly. Geometry information passes upwards through the window hierarchy until eventually a particular size is requested for each top-level window. These requests are called internal requests in the discussion below. The second source of width and height information is through the wm :geometry command. Third, the user can request a particular size for a window using the interactive facilities of the window manager. The second and third types of geometry requests are called external requests in the discussion below; Tk treats these two kinds of requests identically.

#### "Ungridded Geometry Management" ¶

Tk allows the geometry of a top-level window to be managed in either of two general ways: ungridded or gridded. The ungridded form occurs if no wm :grid command has been issued for a top-level window. Ungridded management has several variants. In the simplest variant of ungridded windows, no wm :geometry, wm :minsize, or wm :maxsize commands have been invoked either. In this case, the window’s size is determined totally by the internal requests emanating from the widgets inside the window: Tk will ask the window manager not to permit the user to resize the window interactively.

If a wm :geometry command is invoked on an ungridded window, then the size in that command overrides any size requested by the window’s widgets; from now on, the window’s size will be determined entirely by the most recent information from wm :geometry commands. To go back to using the size requested by the window’s widgets, issue a wm :geometry command with an empty geometry string.

To enable interactive resizing of an ungridded window, one or both of the wm :maxsize and wm :minsize commands must be issued. The information from these commands will be passed to the window manager, and size changes within the specified range will be permitted. For ungridded windows the limits refer to the top-level window’s dimensions in pixels. If only a wm :maxsize command is issued then the minimum dimensions default to 1; if only a wm :minsize command is issued then the maximum dimensions default to the size of the display. If the size of a window is changed interactively, it has the same effect as if wm :geometry had been invoked: from now on, internal geometry requests will be ignored. To return to internal control over the window’s size, issue a wm :geometry command with an empty geometry argument. If a window has been manually resized or moved, the wm :geometry command will return the geometry that was requested interactively.

#### "Gridded Geometry Management" ¶

The second style of geometry management is called gridded. This approach occurs when one of the widgets of an application 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 application. 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 automatically enabled, and it will be carried out in even numbers of grid units rather than pixels. By default there are no limits on the minimum or maximum dimensions of a gridded window. As with ungridded windows, interactive resizing has exactly the same effect as invoking the wm :geometry command. For gridded windows, internally- and externally-requested dimensions work together: the externally-specified width and height determine the size of the window in grid units, and the information from the last wm :grid command maps from grid units to pixel units.

#### Bugs ¶

The window manager interactions seem too complicated, especially for managing geometry. Suggestions on how to simplify this would be greatly appreciated.

Most existing window managers appear to have bugs that affect the operation of the wm command. For example, some changes won’t take effect if the window is already active: the window will have to be withdrawn and de-iconified in order to make the change happen.

#### Keywords ¶

aspect ratio, deiconify, focus model, geometry, grid, group, icon, iconify, increments, position, size, title, top-level window, units, window manager