File Coverage

blib/lib/Chart/Colors.pm

Criterion	Covered	Total	%
statement	47	49	95.9
branch	17	26	65.3
condition			n/a
subroutine	6	6	100.0
pod	3	4	75.0
total	73	85	85.8

package Chart::Colors;

use strict;
use warnings;

# perl -MPod::Markdown -e 'Pod::Markdown->new->filter(@ARGV)' lib/Chart/Colors.pm  > README.md

=head1 NAME

Chart::Colors - Perl extension to return an endless stream of new distinct RGB colours codes (good for coloring any number of chart lines)

=head1 SYNOPSIS


    #!/usr/bin/perl -w

    use Chart::Colors;

    my $colors = new Chart::Colors();
    my $nextcolor_hex=$colors->Next('hex');	# Get an HTML-Style answer, like F85099 (put a # in front to use in HTML, i.e. #F85099)
    my($r,$g,$b)=$colors->Next('rgb');		# Get red, green, and blue ints separately, like (255,123,88)
    my($h,$s,$v)=$colors->Next('hsv');		# Get hue, saturation, and brightness


=head1 DESCRIPTION

This module outputs an infinte sequence of visually distinct different colours.

It is useful for colorizing the lines on charts etc.

=head2 EXAMPLE

	# perl -MChart::Colors -e '$c=new Chart::Colors(); for(my $i=0;$i<5;$i++) { print "$i\t( " . join(", ",$c->Next()) . " )\n";}; print "#" . $c->Next("hex") . "\n"; print join("|", $c->Next("hsv")) . "\n"; '
	0       ( 204, 81, 81 )
	1       ( 127, 51, 51 )
	2       ( 81, 204, 204 )
	3       ( 51, 127, 127 )
	4       ( 142, 204, 81 )
	#597f33
	0.75|0.6|0.8

=head2 EXPORT

None by default.


=head2 Notes

=head2 new

Usage is

    my $colors = new Chart::Colors();


=head2 Next

Returns a colour code in hexadecimal ('hex'), red, green, blue ('rgb') or hue, saturation, and brightnes ('hsv') format.

Usage is

    my $nextcolor_hex = $colors->Next('hex');

or

    my($r,$g,$b)=$colors->Next('rgb');

or

    my($h,$s,$v)=$colors->Next('hsv');


=head2 hsv_to_rgb

    my($r,$g,$b)=$this->hsv_to_rgb($h,$s,$v);

=cut

require Exporter;

our @ISA = qw(Exporter);
our($VERSION)='1.03';
our($UntarError) = '';

our %EXPORT_TAGS = ( 'all' => [ qw( ) ] );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our @EXPORT = qw( );


sub new {
  my $class = shift;
  my $this={};
  $this->{rgbno}=0;
  @{$this->{rgbf}}=(0.8,0.5);
  $this->{base}=1;
  $this->{num}=1;
  $this->{ff}=undef;
  bless $this,$class;
  return $this;
} # new



sub Next {
  my $this = shift;
  my $type = shift; # 'hex' or 'rgb' or 'hsv'
  $type='' unless($type);

  $this->{ff}=$this->nextfrac() unless($this->{rgbno}%2);
  my($h,$s,$v)=($this->{ff},.6,$this->{rgbf}->[$this->{rgbno}++%2]);
  return ($h,$s,$v) if($type eq 'hsv');
  #return($this->hsv_to_rgb($ff,.6,$this->{rgbf[$this->{rgbno}++%2]}));	# RGB
  my($r,$g,$b)=$this->hsv_to_rgb($h,$s,$v);
  return sprintf("%02x%02x%02x",$r,$g,$b) if($type eq 'hex');
  return($r,$g,$b) if($type eq 'rgb');
  return($r,$g,$b); # default to RGB
  #return($this->hsv_to_rgb($h,$s,$v)) if($type eq 'rgb');	# RGB
} # Next
# testing Next: perl -MChart::Colors -e '$c=new Chart::Colors(); for(my $i=0;$i<5;$i++) { print "$i\t( " . join(", ",$c->Next()) . " )\n"; }'  # correct= ['204,81,81', '127,51,51', '81,204,204', '51,127,127', '142,204,81']

sub nextfrac {	# Keep slicing between previous 0..1 range.
  my $this = shift;
  my $ret=($this->{base}==1)? 0: $this->{num}/$this->{base};
  $this->{num}+=2;
  if($this->{num}>$this->{base}) {
    $this->{base}=2*$this->{base};
    $this->{num}=1;
  }
  return $ret;
} # nextfrac
# testing nextfrac: for(my $i=0;$i<20;$i++) { print "$i\t" . &nextfrac() . "\n"; } # correct= [0.0, 0.5, 0.25, 0.75, 0.125, 0.375, 0.625, 0.875, 0.0625, 0.1875, ...]

sub hsv_to_rgb {
  my $this = shift;
  my($h,$s,$v)=@_;		# All numbers range from 0..1
  #print "h=$h s=$s v=$v\n";
  return(0,0,0) if(!$s);	# Black is black
  my $i = int($h*6);
  my $f = $h*6-$i;
  my $p = int(255*($v*(1-$s)));
  my $q = int(255*($v*(1-$s*$f)));
  my $t = int(255*($v*(1-$s*(1-$f))));
  $v=int($v*255);
  $i%=6;
  return ($v, $t, $p) if($i == 0);
  return ($q, $v, $p) if($i == 1);
  return ($p, $v, $t) if($i == 2);
  return ($p, $q, $v) if($i == 3);
  return ($t, $p, $v) if($i == 4);
  return ($v, $p, $q); # if($i == 5)
} # hsv_to_rgb
# testing hsv_to_rgb: my $x; while( $x++<20){ my($h,$s,$v)=(rand(),rand(),rand()); print "($h,$s,$v)=(" . join(",",&hsv_to_rgb($h,$s,$v)) . ")\n"; };

#my $toprint=$ARGV[0]; $toprint++ unless($toprint); my @ret;push @ret,"'" . join(",",&Next()) . "'" while($toprint--); print "[". join(", ",@ret) . "]\n";


1;

__END__