Provided by: tk8.6-doc_8.6.8-4_all 
NAME
fontchooser - control font selection dialog
SYNOPSIS
tk fontchooser configure ?-option value -option value ...?
tk fontchooser show
tk fontchooser hide
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DESCRIPTION
The tk fontchooser command controls the Tk font selection dialog. It uses the native platform font
selection dialog where available, or a dialog implemented in Tcl otherwise.
Unlike most of the other Tk dialog commands, tk fontchooser does not return an immediate result, as on
some platforms (Mac OS X) the standard font dialog is modeless while on others (Windows) it is modal. To
accommodate this difference, all user interaction with the dialog will be communicated to the caller via
callbacks or virtual events.
The tk fontchooser command can have one of the following forms:
tk fontchooser configure ?-option value -option value ...?
Set or query one or more of the configurations options below (analogous to Tk widget
configuration).
tk fontchooser show
Show the font selection dialog. Depending on the platform, may return immediately or only once the
dialog has been withdrawn.
tk fontchooser hide
Hide the font selection dialog if it is visible and cause any pending tk fontchooser show command
to return.
CONFIGURATION OPTIONS
-parent
Specifies/returns the logical parent window of the font selection dialog (similar to the -parent
option to other dialogs). The font selection dialog is hidden if it is visible when the parent
window is destroyed.
-title Specifies/returns the title of the dialog. Has no effect on platforms where the font selection
dialog does not support titles.
-font Specifies/returns the font that is currently selected in the dialog if it is visible, or that will
be initially selected when the dialog is shown (if supported by the platform). Can be set to the
empty string to indicate that no font should be selected. Fonts can be specified in any form given
by the "FONT DESCRIPTION" section in the font manual page.
-command
Specifies/returns the command prefix to be called when a font selection has been made by the user.
The command prefix is evaluated at the global level after having the specification of the selected
font appended. On platforms where the font selection dialog offers the user control of further
font attributes (such as color), additional key/value pairs may be appended before evaluation. Can
be set to the empty string to indicate that no callback should be invoked. Fonts are specified by
a list of form [3] of the "FONT DESCRIPTION" section in the font manual page (i.e. a list of the
form {family size style ?style ...?}).
-visible
Read-only option that returns a boolean indicating whether the font selection dialog is currently
visible. Attempting to set this option results in an error.
VIRTUAL EVENTS
<<TkFontchooserVisibility>>
Sent to the dialog parent whenever the visibility of the font selection dialog changes, both as a
result of user action (e.g. disposing of the dialog via OK/Cancel button or close box) and of the
tk fontchooser show/hide commands being called. Binding scripts can determine the current
visibility of the dialog by querying the -visible configuration option.
<<TkFontchooserFontChanged>>
Sent to the dialog parent whenever the font selection dialog is visible and the selected font
changes, both as a result of user action and of the -font configuration option being set. Binding
scripts can determine the currently selected font by querying the -font configuration option.
NOTES
Callers should not expect a result from tk fontchooser show and may not assume that the dialog has been
withdrawn or closed when the command returns. All user interaction with the dialog is communicated to the
caller via the -command callback and the <<TkFontchooser*>> virtual events. It is implementation
dependent which exact user actions result in the callback being called resp. the virtual events being
sent. Where an Apply or OK button is present in the dialog, that button will trigger the -command
callback and <<TkFontchooserFontChanged>> virtual event. On some implementations other user actions may
also have that effect; on Mac OS X for instance, the standard font selection dialog immediately reflects
all user choices to the caller.
In the presence of multiple widgets intended to be influenced by the font selection dialog, care needs to
be taken to correctly handle focus changes: the font selected in the dialog should always match the
current font of the widget with the focus, and the -command callback should only act on the widget with
the focus. The recommended practice is to set font dialog -font and -command configuration options in
per-widget <FocusIn> handlers (and if necessary to unset them - i.e. set to the empty string - in
corresponding <FocusOut> handlers). This is particularly important for implementers of library code using
the font selection dialog, to avoid conflicting with application code that may also want to use the
dialog.
Because the font selection dialog is application-global, in the presence of multiple interpreters calling
tk fontchooser, only the -command callback set by the interpreter that most recently called tk
fontchooser configure or tk fontchooser show will be invoked in response to user action and only the
-parent set by that interpreter will receive <<TkFontchooser*>> virtual events.
The font dialog implementation may only store (and return) font actual data as the value of the -font
configuration option. This can be an issue when -font is set to a named font, if that font is
subsequently changed, the font dialog -font option needs to be set again to ensure its selected font
matches the new value of the named font.
EXAMPLE
proc fontchooserDemo {} {
wm title . "Font Chooser Demo"
tk fontchooser configure -parent .
button .b -command fontchooserToggle -takefocus 0
fontchooserVisibility .b
bind . <<TkFontchooserVisibility>> \
[list fontchooserVisibility .b]
foreach w {.t1 .t2} {
text $w -width 20 -height 4 -borderwidth 1 -relief solid
bind $w <FocusIn> [list fontchooserFocus $w]
$w insert end "Text Widget $w"
}
.t1 configure -font {Courier 14}
.t2 configure -font {Times 16}
pack .b .t1 .t2; focus .t1
}
proc fontchooserToggle {} {
tk fontchooser [expr {
[tk fontchooser configure -visible] ?
"hide" : "show"}]
}
proc fontchooserVisibility {w} {
$w configure -text [expr {
[tk fontchooser configure -visible] ?
"Hide Font Dialog" : "Show Font Dialog"}]
}
proc fontchooserFocus {w} {
tk fontchooser configure -font [$w cget -font] \
-command [list fontchooserFontSelection $w]
}
proc fontchooserFontSelection {w font args} {
$w configure -font [font actual $font]
}
fontchooserDemo
SEE ALSO
font(3tk), tk(3tk)
KEYWORDS
dialog, font, font selection, font chooser, font panel