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fontchooser(3tk) Tk Built-In Commands fontchooser(3tk) 





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:



  

  
Set or query one or more of the configurations options below (analogous to
      Tk widget configuration).

  

  
Show the font selection dialog. Depending on the platform, may return
      immediately or only once the dialog has been withdrawn.

  

  
Hide the font selection dialog if it is visible and cause any pending
      tk fontchooser show command to return.








CONFIGURATION OPTIONS



  

  
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.

  

  
Specifies/returns the title of the dialog. Has no effect on platforms
      where the font selection dialog does not support titles.

  

  
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.

  

  
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
    ...?}).

  

  
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(3tk), tk(3tk)






KEYWORDS


dialog, font, font selection, font chooser, font panel







  

    
    Tk