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+#==========================================================================
+# Copyright (c) 1995-1998 Martien Verbruggen
+#--------------------------------------------------------------------------
+#
+# Name:
+# GD::Graph::colour.pm
+#
+# Description:
+# Package of colour manipulation routines, to be used
+# with GD::Graph.
+#
+# $Id: colour.pm,v 1.10 2003/02/11 05:38:46 mgjv Exp $
+#
+#==========================================================================
+
+
+package GD::Graph::colour;
+
+($GD::Graph::colour::VERSION) = '$Revision: 1.10 $' =~ /\s([\d.]+)/;
+
+=head1 NAME
+
+GD::Graph::colour - Colour manipulation routines for use with GD::Graph
+
+=head1 SYNOPSIS
+
+use GD::Graph::colour qw(:colours :lists :files :convert);
+
+=head1 DESCRIPTION
+
+The B<GD::Graph::colour> package provides a few routines to work with
+colours. The functionality of this package is mainly defined by what is
+needed, now and historically, by the GD::Graph modules.
+
+=cut
+
+use vars qw( @EXPORT_OK %EXPORT_TAGS );
+use strict;
+require Exporter;
+use Carp;
+
+@GD::Graph::colour::ISA = qw( Exporter );
+
+@EXPORT_OK = qw(
+ _rgb _luminance _hue add_colour
+ colour_list sorted_colour_list
+ read_rgb
+ hex2rgb rgb2hex
+);
+%EXPORT_TAGS = (
+ colours => [qw( add_colour _rgb _luminance _hue )],
+ lists => [qw( colour_list sorted_colour_list )],
+ files => [qw( read_rgb )],
+ convert => [qw( hex2rgb rgb2hex )],
+);
+
+my %RGB = (
+ white => [0xFF,0xFF,0xFF],
+ lgray => [0xBF,0xBF,0xBF],
+ gray => [0x7F,0x7F,0x7F],
+ dgray => [0x3F,0x3F,0x3F],
+ black => [0x00,0x00,0x00],
+ lblue => [0x00,0x00,0xFF],
+ blue => [0x00,0x00,0xBF],
+ dblue => [0x00,0x00,0x7F],
+ gold => [0xFF,0xD7,0x00],
+ lyellow => [0xFF,0xFF,0x00],
+ yellow => [0xBF,0xBF,0x00],
+ dyellow => [0x7F,0x7F,0x00],
+ lgreen => [0x00,0xFF,0x00],
+ green => [0x00,0xBF,0x00],
+ dgreen => [0x00,0x7F,0x00],
+ lred => [0xFF,0x00,0x00],
+ red => [0xBF,0x00,0x00],
+ dred => [0x7F,0x00,0x00],
+ lpurple => [0xFF,0x00,0xFF],
+ purple => [0xBF,0x00,0xBF],
+ dpurple => [0x7F,0x00,0x7F],
+ lorange => [0xFF,0xB7,0x00],
+ orange => [0xFF,0x7F,0x00],
+ pink => [0xFF,0xB7,0xC1],
+ dpink => [0xFF,0x69,0xB4],
+ marine => [0x7F,0x7F,0xFF],
+ cyan => [0x00,0xFF,0xFF],
+ lbrown => [0xD2,0xB4,0x8C],
+ dbrown => [0xA5,0x2A,0x2A],
+);
+
+=head1 FUNCTIONS
+
+=head2 colour_list( I<number of colours> )
+
+Returns a list of I<number of colours> colour names known to the package.
+Exported with the :lists tag.
+
+=cut
+
+sub colour_list
+{
+ my $n = ( $_[0] ) ? $_[0] : keys %RGB;
+ return (keys %RGB)[0 .. $n-1];
+}
+
+=head2 sorted_colour_list( I<number of colours> )
+
+Returns a list of I<number of colours> colour names known to the package,
+sorted by luminance or hue.
+B<NB.> Right now it always sorts by luminance. Will add an option in a later
+stage to decide sorting method at run time.
+Exported with the :lists tag.
+
+=cut
+
+sub sorted_colour_list
+{
+ my $n = $_[0] ? $_[0] : keys %RGB;
+ return (sort by_luminance keys %RGB)[0 .. $n-1];
+ # return (sort by_hue keys %rgb)[0..$n-1];
+
+ sub by_luminance { _luminance(@{$RGB{$b}}) <=> _luminance(@{$RGB{$a}}) }
+ sub by_hue { _hue(@{$RGB{$b}}) <=> _hue(@{$RGB{$a}}) }
+}
+
+=head2 _rgb( I<colour name> )
+
+Returns a list of the RGB values of I<colour name>. if the colour name
+is a string of the form that is acceptable to the hex2rgb sub, then the
+colour will be added to the list dynamically.
+Exported with the :colours tag.
+
+=cut
+
+my %warned_clrs = ();
+
+# return the RGB values of the colour name
+sub _rgb
+{
+ my $clr = shift or return;
+
+ # Try adding the colour if it doesn't exist yet. It may be of a
+ # parseable form
+ add_colour($clr) unless exists $RGB{$clr};
+
+ my $rgb_ref = $RGB{$clr};
+ if (!defined $rgb_ref)
+ {
+ $rgb_ref = $RGB{'black'};
+ unless ($warned_clrs{$clr})
+ {
+ $warned_clrs{$clr}++;
+ carp "Colour $clr is not defined, reverting to black";
+ }
+ };
+
+ @{$rgb_ref};
+}
+
+=head2 _hue( I<R,G,B> )
+
+Returns the hue of the colour with the specified RGB values.
+Exported with the :colours tag.
+
+=head2 _luminance( I<R,G,B> )
+
+Returns the luminance of the colour with the specified RGB values.
+Exported with the :colours tag.
+
+=cut
+
+# return the luminance of the colour (RGB)
+sub _luminance
+{
+ (0.212671 * $_[0] + 0.715160 * $_[1] + 0.072169 * $_[2])/0xFF
+}
+
+# return the hue of the colour (RGB)
+sub _hue
+{
+ ($_[0] + $_[1] + $_[2])/(3 * 0xFF)
+}
+
+=head2 add_colour(colourname => [$r, $g, $b]) or
+add_colour('#7fe310')
+
+Self-explanatory.
+Exported with the :colours tag.
+
+=cut
+
+sub add_colour
+{
+ my $name = shift;
+ my $val = shift;
+
+ if (!defined $val)
+ {
+ my @rgb = hex2rgb($name) or return;
+ $val = [@rgb];
+ }
+
+ if (ref $val && ref $val eq 'ARRAY')
+ {
+ $RGB{$name} = [@{$val}];
+ return $name;
+ }
+
+ return;
+}
+
+=head2 rgb2hex($red, $green, $blue)
+
+=head2 hex2rgb('#7fe310')
+
+These functions translate a list of RGB values into a hexadecimal
+string, as is commonly used in HTML and the Image::Magick API, and vice
+versa.
+Exported with the :convert tag.
+
+=cut
+
+# Color translation
+sub rgb2hex
+{
+ return unless @_ == 3;
+ my $color = '#';
+ foreach my $cc (@_)
+ {
+ $color .= sprintf("%02x", $cc);
+ }
+ return $color;
+}
+
+sub hex2rgb
+{
+ my $clr = shift;
+ my @rgb = $clr =~ /^#([a-f0-9]{2})([a-f0-9]{2})([a-f0-9]{2})$/i;
+ return unless @rgb;
+ return map { hex $_ } @rgb;
+}
+
+=head2 read_rgb( F<file name> )
+
+Reads in colours from a rgb file as used by the X11 system.
+
+Doing something like:
+
+ use GD::Graph::bars;
+ use GD::Graph::colour;
+
+ GD::Graph::colour::read_rgb("rgb.txt") or die "cannot read colours";
+
+Will allow you to use any colours defined in rgb.txt in your graph.
+Exported with the :files tag.
+
+=cut
+
+#
+# Read a rgb.txt file (X11)
+#
+# Expected format of the file:
+#
+# R G B colour name
+#
+# Fields can be separated by any number of whitespace
+# Lines starting with an exclamation mark (!) are comment and
+# will be ignored.
+#
+# returns number of colours read
+
+sub read_rgb($) # (filename)
+{
+ my $fn = shift;
+ my $n = 0;
+ my $line;
+
+ open(RGB, $fn) or return 0;
+
+ while (defined($line = <RGB>))
+ {
+ next if ($line =~ /\s*!/);
+ chomp($line);
+
+ # remove leading white space
+ $line =~ s/^\s+//;
+
+ # get the colours
+ my ($r, $g, $b, $name) = split(/\s+/, $line, 4);
+
+ # Ignore bad lines
+ next unless (defined $name);
+
+ $RGB{$name} = [$r, $g, $b];
+ $n++;
+ }
+
+ close(RGB);
+
+ return $n;
+}
+
+sub version { $GD::Graph::colour::VERSION }
+
+sub dump_colours
+{
+ my $max = $_[0] ? $_[0] : keys %RGB;
+ my $n = 0;
+
+ my $clr;
+ foreach $clr (sorted_colour_list($max))
+ {
+ last if $n > $max;
+ print "colour: $clr, " .
+ "${$RGB{$clr}}[0], ${$RGB{$clr}}[1], ${$RGB{$clr}}[2]\n"
+ }
+}
+
+
+"Just another true value";
+
+__END__
+
+=head1 PREDEFINED COLOUR NAMES
+
+white,
+lgray,
+gray,
+dgray,
+black,
+lblue,
+blue,
+dblue,
+gold,
+lyellow,
+yellow,
+dyellow,
+lgreen,
+green,
+dgreen,
+lred,
+red,
+dred,
+lpurple,
+purple,
+dpurple,
+lorange,
+orange,
+pink,
+dpink,
+marine,
+cyan,
+lbrown,
+dbrown.
+
+=head1 AUTHOR
+
+Martien Verbruggen E<lt>mgjv@tradingpost.com.auE<gt>
+
+=head2 Copyright
+
+GIFgraph: Copyright (c) 1995-1999 Martien Verbruggen.
+Chart::PNGgraph: Copyright (c) 1999 Steve Bonds.
+GD::Graph: Copyright (c) 1999 Martien Verbruggen.
+
+All rights reserved. This package is free software; you can redistribute
+it and/or modify it under the same terms as Perl itself.
+
+=head1 SEE ALSO
+
+L<GD::Graph>,
+L<GD::Graph::FAQ>
+
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