Provided by: tk9.0-doc_9.0.1-1_all 
NAME
tk - Manipulate Tk internal state
SYNOPSIS
tk option ?arg ...?
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DESCRIPTION
The tk command provides access to miscellaneous elements of Tk's internal state. Most of the information
manipulated by this command pertains 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 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 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 busy subcommand ...
This command controls the marking of window hierarchies as “busy”, rendering them non-interactive
while some other operation is proceeding. For more details see the busy manual page.
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 cursor location, or the height of the specified window if none is
given.
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 window.
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
an error if tried.
tk fontchooser subcommand ...
Controls the Tk font selection dialog. For more details see the fontchooser manual page.
tk print window
The tk print command posts a dialog that allows users to print output from the canvas and text
widgets. The printing will be done using platform-native APIs and dialogs where available. For
more details see the print manual page.
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 millimeters) 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 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, 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.
tk sysnotify title? message?
The tk sysnotify command creates a platform-specific system notification alert. Its intent is to
provide a brief, unobtrusive notification to the user by popping up a window that briefly appears
in a corner of the screen. For more details see the sysnotify manual page.
tk systray create subcommand...
The tk systray command creates an icon in the platform-specific tray. For more details see the
systray manual page.
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.
tk windowingsystem
Returns the current Tk windowing system, one of x11 (X11-based), win32 (MS Windows), or aqua
(macOS Aqua).
SEE ALSO
busy(3tk), fontchooser(3tk), print(3tk), send(3tk), sysnotify(3tk), systray(3tk), winfo(3tk)
KEYWORDS
application name, print, send, sysnotify, systray
Tk 8.4 tk(3tk)