• NAME
• SYNOPSIS
• DESCRIPTION
• STANDARD OPTIONS
• WIDGET-SPECIFIC METHODS
  • disabled_gradientcolor
  • enabled_gradientcolor
  • get_gradientcolor
  • set_gradientcolor
  • rgb_to_hex
  • hex_to_rgb
• EXAMPLES
• AUTHOR
• BUGS
• SEE ALSO
• SUPPORT
• ACKNOWLEDGEMENTS
• COPYRIGHT & LICENSE

Tk::Canvas::GradientColor - To create a Canvas widget with background gradient color.

 #!/usr/bin/perl
 use strict;
 use warnings;
 
 use Tk;
 use Tk::Canvas::GradientColor;
 
 my $mw = MainWindow->new(
   -title      => 'Tk::Canvas::GradientColor',
   -background => 'white',
 );
 
 my $canvas = $mw->GradientColor(
   -width  => 400,
   -height => 400,
 )->pack(qw/ -fill both -expand 1 /);
 
 $mw->update;
 sleep 3;
 
 # Change color
 $canvas->set_gradientcolor(
   -start_color => '#000000',
   -end_color   => '#00CDFF',
 );
 
 $mw->update;
 sleep 3;
 
 # Change type
 $canvas->set_gradientcolor(
   -start       => 50,
   -end         => 100,
   -type        => 'mirror_vertical'
 );
 
 MainLoop();

Tk::Canvas::GradientColor is an extension of the Canvas widget. It is an easy way to build a canvas widget with gradient background color.

-background -borderwidth -closeenough -confine -cursor -height -highlightbackground -highlightcolor -highlightthickness -insertbackground -insertborderwidth -insertofftime -insertontime -insertwidth -relief -scrollregion -selectbackground -selectborderwidth -selectforeground -takefocus -width -xscrollcommand -xscrollincrement -yscrollcommand -yscrollincrement

The Canvas method creates a widget object. This object supports the configure and cget methods described in Tk::options which can be used to enquire and modify the options described above.

disabled_gradientcolor

$canvas_bg->disabled_gradientcolor

Disabled background gradient color. The canvas widget will have the background color set by -background option.

$canvas_bg->disabled_gradientcolor;  

enabled_gradientcolor

$canvas_bg->enabled_gradientcolor

Enabled background gradient color. Background gradient color is activated by default. Use this method if disabled_gradientcolor method is called.

$canvas_bg->enabled_gradientcolor;  

get_gradientcolor

$canvas_bg->get_gradientcolor

Return a hash reference which contains the options to create the background gradient color.

my $ref_gradient_options = $canvas_bg->get_gradientcolor;  

set_gradientcolor

$canvas_bg->set_gradientcolor(?options)

• -type

  8 types are available : linear_horizontal, linear_vertical, mirror_horizontal, mirror_vertical, radial, losange, corner_right and corner_left.

  -type => 'corner_left',

  Default : linear_horizontal

• -start_color

  First color of gradient color.

  -start_color => 'red',

  Default : #8BC2F5

• -end_color

  Last color of gradient color.

  -end_color => '#FFCD9F',

  Default : white

• -start

  -start => 50, # Must be >= 0, <= 100 and start < end

  Use it for linear_horizontal and linear_vertical type. The first color starts at 'start' percent width of canvas. The easy way to understand is to test the example in this documentation.

  Ex : width canvas = 1000px, start = 50 : the first part of canvas has the background color of start_color and the gradient color start at 500px.

  Default : 0

  Use it for mirror_horizontal and mirror_vertical type. The first color starts at 'start' percent width of canvas. The easy way to understand is to test the example in this documentation.

  Ex : width canvas = 1000px, start = 50 : the background gradient color begins at 50 percent in two directions.

  Default : 50

• -end

  -end => 80,  # Must be >= 0, <= 100 and end > start

  Use it for linear_horizontal and linear_vertical type. The last color finishes at 'end' percent width of canvas. The easy way to understand is to test the example in this documentation.

  Default : 100

  Use it for mirror_horizontal and mirror_vertical type. The last color finishes at 'end' percent width of canvas and opposite. The easy way to understand is to test the example in this documentation.

  Default : 100

• -number_color

  Number of colors between first and last color to create the gradient.

  -number_color => 200, 

  Default : 100

rgb_to_hex

$canvas_bg->rgb_to_hex($red, $green, $blue)

Return hexa code of rgb color.

my $color = $canvas_bg->rgb_to_hex(200, 102, 65);  # return #C86641

hex_to_rgb

$canvas_bg->hex_to_rgb(string)

Return an array with red, green an blue code rgb color.

my ( $red, $green, $blue ) = $canvas_bg->hex_to_rgb('#C86641');  # return 200, 102, 65
my ( $red, $green, $blue ) = $canvas_bg->hex_to_rgb('gray');     # return 190, 190, 190

An example to test the configuration of the widget:

 #!/usr/bin/perl
 use strict;
 use warnings;
 
 use Tk;
 use Tk::Canvas::GradientColor;
 use Tk::BrowseEntry;
 
 my $mw = MainWindow->new(
   -title      => 'gradient color with canvas',
   -background => 'snow',
 );
 
 my $canvas = $mw->GradientColor(
   -background => '#005500',
   -width      => 500,
   -height     => 500,
 )->pack(qw/ -fill both -expand 1 /);
 
 my %arg_gradient = (
   -type         => undef,
   -start_color  => '#A780C1',
   -end_color    => 'white',
   -start        => undef,
   -end          => undef,
   -number_color => undef,
 );
 
 # configure start color
 my $bouton_color1 = $canvas->Button(
   -text    => 'select color start',
   -command => sub {
     $arg_gradient{-start_color} = $canvas->chooseColor( -title => 'select color start' );
     $canvas->set_gradientcolor(%arg_gradient);
   },
 );
 
 # configure end color
 my $bouton_color2 = $canvas->Button(
   -text    => 'select color end',
   -command => sub {
     $arg_gradient{-end_color} = $canvas->chooseColor( -title => 'select color end' );
     $canvas->set_gradientcolor(%arg_gradient);
   },
 );
 
 my $type = $canvas->BrowseEntry(
   -label   => 'Type gradient color',
   -choices => [
     qw/ linear_horizontal linear_vertical mirror_horizontal mirror_vertical radial losange corner_right corner_left/
   ],
     -background => 'white',
   -state              => 'readonly',
   -disabledbackground => 'yellow',
   -browsecmd          => sub {
     my ( $widget, $selection ) = @_;
     $arg_gradient{-type} = $selection;
     $canvas->set_gradientcolor(%arg_gradient);
   },
 );
 
 my $start_num = $canvas->Scale(
   -background   => 'white',
   -label        => 'Start',
   -from         => 0,
   -to           => 100,
   -variable     => 0,
   -orient       => 'horizontal',
   -sliderlength => 10,
   -command      => sub {
     my $selection = shift;
     $arg_gradient{-start} = $selection;
     $canvas->set_gradientcolor(%arg_gradient);
   },
 );
 
 my $end_num = $canvas->Scale(
   -background   => 'white',
   -label        => 'End',
   -from         => 0,
   -to           => 100,
   -variable     => '100',
   -orient       => 'horizontal',
   -sliderlength => 10,
   -command      => sub {
     my $selection = shift;
     $arg_gradient{-end} = $selection;
     $canvas->set_gradientcolor(%arg_gradient);
   },
 );
 my $num                = 100;
 my $entry_number_color = $canvas->BrowseEntry(
   -label              => 'Number color',
   -choices            => [qw/ 2 3 4 5 10 50 100 150 200 250 300 400 500 750 1000 1500 2000 2500/],
   -state              => 'readonly',
   -disabledbackground => 'yellow',
   -background => 'white',
   -variable           => \$num,
   -browsecmd          => sub {
     my ( $widget, $selection ) = @_;
     $arg_gradient{-number_color} = $selection;
     $canvas->set_gradientcolor(%arg_gradient);
   },
 );
 
 my $disabled_gradientcolor = $canvas->Button(
   -text    => 'disabled_gradientcolor',
   -command => sub { $canvas->disabled_gradientcolor; },
 );
 my $enabled_gradientcolor = $canvas->Button(
   -text    => 'enabled_gradientcolor',
   -command => sub { $canvas->enabled_gradientcolor; },
 );
 
 $canvas->createWindow( 100, 100, -window => $bouton_color1 );
 $canvas->createWindow( 400, 100, -window => $bouton_color2 );
 $canvas->createWindow( 100, 150, -window => $start_num );
 $canvas->createWindow( 100, 200, -window => $end_num );
 $canvas->createWindow( 350, 150, -window => $entry_number_color );
 $canvas->createWindow( 350, 200, -window => $type );
 $canvas->createWindow( 100, 350, -window => $disabled_gradientcolor );
 $canvas->createWindow( 400, 350, -window => $enabled_gradientcolor );
 
 MainLoop;

Djibril Ousmanou, <djibel at cpan.org>

Please report any bugs or feature requests to bug-Tk-Canvas-GradientColor at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Tk-Canvas-GradientColor. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

See Tk::Canvas for details of the standard options.

You can find documentation for this module with the perldoc command.

perldoc Tk::Canvas::GradientColor

You can also look for information at:

• RT: CPAN's request tracker

  http://rt.cpan.org/NoAuth/Bugs.html?Dist=Tk-Canvas-GradientColor

• AnnoCPAN: Annotated CPAN documentation

  http://annocpan.org/dist/Tk-Canvas-GradientColor

• CPAN Ratings

  http://cpanratings.perl.org/d/Tk-Canvas-GradientColor

• Search CPAN

  http://search.cpan.org/dist/Tk-Canvas-GradientColor/

Copyright 2014 Djibril Ousmanou, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.