fontchooser(n) Tk Built-In Commands fontchooser(n) ______________________________________________________________________________
NAME
fontchooser - control font selection dialog
SYNOPSIS
tk fontchooser configure ?-option value ...?
tk fontchooser show
tk fontchooser hide
______________________________________________________________________________
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 (macOS) 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 ...?
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return immediately or only once the dialog has been withdrawn.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 macOS 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(n), tk(n)
KEYWORDS
dialog, font, font selection, font chooser, font panel
Tk fontchooser(n)
tk 8.6.15 - Generated Wed Dec 4 15:59:14 CST 2024