ColourChooser - Perl/Tk module providing a Colour selection dialogue

        use Tk::ColourChooser ; 

        my $col_dialog = $Window->ColourChooser ;
        my $colour     = $col_dialog->Show ;
        if( $colour ) {
            # They pressed OK and the colour chosen is in $colour - could be
            # transparent which is 'None' unless -transparent is set.
        else {
            # They cancelled.

        # May optionally have the colour initialised.
        my $col_dialog = $Window->ColourChooser( -colour => 'green' ) ;
        my $col_dialog = $Window->ColourChooser( -colour => '#0A057C' ) ;

        # The title may also be overridden; and we can insist that only hex values
        # are returned rather than colour names. We can disallow transparent.
        my $col_dialog = $Window->ColourChooser( 
                            -language    => 'en', # Or 'de' or 'fr'.
                            -title       => 'Select a colour',
                            -colour      => '0A057C',
                            -transparent => 0,
                            -hexonly     => 1,
                            -showhex     => 1,
                            ) ;

    ColourChooser is a dialogue box which allows the user to pick a colour
    from the list in rgb.txt (supplied with X Windows), or to create a
    colour by setting RGB (red, green, blue) values with slider controls.

    You can scroll through all the named colours by using the <Down> and
    <Up> arrow keys on the keyboard or by clicking the mouse on the
    scrollbar and then clicking the colour list.

    "-language" This is optional. Default is `en'. This option allows you to
    set the language for the title and labels. Valid values are "en"
    (english), "de" (german), "fr" (french) and "english" (for backward
    compatibility) which is also the default. Translations are by Babelfish.
    Other languages will be added if people provide translations.
    "-title" This is optional and allows you to set the title. Default is
    'Colour Chooser' in the "-language" specified.
    "-colour" This is optional and allows you to specify the colour that is
    shown when the dialogue is invoked. It may be specified as a colour name
    from rgb.txt or as a six digit hex number with an optional leading hash,
    i.e. as 'HHHHHH' or '#HHHHHH'. Default is 'black'.
    "-hexonly" This is optional. If set to 1 it forces the ColourChooser to
    only return colours as hex numbers in Tk format ('#HHHHHH'); if set to 0
    it returns colours as names if they are named in rgb.txt, and as hex
    numbers if they have no name. Transparent is always returned as 'None'
    however. Default is 0.
    "-transparent" This is optional. If set to 0 it stops ColourChooser
    offering the Transparent button so that only valid colours may be chosen
    - or cancel. Default is 1.
    "-showhex" This is optional. If set to 1 it shows the hex value of the
    colour in the title bar. Default is 0.

    The user has three options:

    Pressing OK will return the selected colour, as a name if it has one or
    as an RGB value if it doesn't. (Colours which do not have names are
    listed as 'Unnamed' in the colour list box.) If the "-hexonly" option
    has been specified the colour is always returned as a Tk colour hex
    value, i.e. in the form '#HHHHHH' except if Transparent is chosen in
    which case 'None' is returned.

    OK is pressed by a mouse click or <Return> or <o> or <Control-o> or

    Pressing Transparent will return the string 'None' which is xpm's name
    for transparent.

    Transparent is pressed by a mouse click or <t> or <Control-t> or

    Pressing Cancel will return an empty string.

    Cancel is pressed by a mouse click or <Escape> or <c> or <Control-c> or
    <Alt-c>. (Note that if the language is not english then the letter to
    press will be the first letter of the translation of the word 'Cancel'.

INSTALLATION should be placed in any Tk directory in any lib
    directory in Perl's %INC path, for example, '/usr/lib/perl5/Tk'.

    ColourChooser looks for the file rgb.txt on your system - if it can't
    find it you will only be able to specify colours by RGB value. Or you
    can set the environment variable RGB_TEXT to the filename.

        Inherited from Tk::Toplevel

        Inherited from Tk::Toplevel

    Does almost no error checking.

    Can be slow to load because rgb.txt is large; however we now load a
    single instance of the colour names when the module is first used and
    these names are then shared.

    If you scroll the list by keyboard or use the mouse to move the colour
    sliders the colour updates as you go; but if you use the mouse on the
    scrollbar you must click the colour name box for the colour to update. I
    don't know why this is and any advice on how to fix it would be welcome.

    Tina Mueller

    This module was developed by Mark Summerfield <>
    until version 1.50.

    The code draws from Stephen O. Lidie's work.

    Copyright (c) Mark Summerfield 1999-2000. All Rights Reserved.

    This module may be used/distributed/modified under the LGPL.