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or only once the dialog has been withdrawn.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