tk(n) Tk Built-In Commands tk(n)
tk - Manipulate Tk internal state
tk option ?arg arg ...?
The tk command provides access to miscellaneous elements of Tk's internal state. Most of the information manipulated by this command per-
tains to the application as a whole, or to a screen or display, rather than to a particular window. The command can take any of a number
of different forms depending on the option argument. The legal forms are:
tk appname ?newName?
If newName is not specified, this command returns the name of the application (the name that may be used in send commands to commu-
nicate 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 command'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 reenable them and recreate the send command.
tk caret window ?-x x? ?-y y? ?-height height?
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 cur-
sor location, or the height of the specified window if none is given.
tk scaling ?-displayof window? ?number?
Sets and queries the current scaling factor used by Tk to convert between physical units (for example, points, inches, or millime-
ters) and pixels. The number argument is a floating point number that specifies the number of pixels per point on window's display.
If the window argument is omitted, it defaults to the main window. 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 equiva-
lent 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, but it can be changed at any time. Measurements made after the scaling factor is changed will use the new scal-
ing factor, but it is undefined whether existing widgets will resize themselves dynamically to accommodate the new scaling factor.
tk inactive ?-displayof window? ?reset?
Returns a positive integer, the number of milliseconds since the last time the user interacted with the system. If the -displayof
option is given then the return value refers to the display of window; otherwise it refers to the display of the application's main
tk inactive will return -1, if querying the user inactive time is not supported by the system, and in safe interpreters.
If the literal string reset is given as an additional argument, the timer is reset and an empty string is returned. Resetting the
inactivity time is forbidden in safe interpreters and will throw and error if tried.
tk useinputmethods ?-displayof window? ?boolean?
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 (i.e., 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 window argument is omitted, it defaults to the main window. If the
boolean argument is omitted, the current state is returned. This is turned on by default for the main display.
Returns the current Tk windowing system, one of x11 (X11-based), win32 (MS Windows), or aqua (Mac OS X Aqua).
application name, send
Tk 8.4 tk(n)