NAME

       Imager::Color - Color handling for Imager.

SYNOPSIS

         use Imager;

         $color = Imager::Color->new($red, $green, $blue);
         $color = Imager::Color->new($red, $green, $blue, $alpha);
         $color = Imager::Color->new("#C0C0FF"); # html color specification

         $color->set($red, $green, $blue);
         $color->set($red, $green, $blue, $alpha);
         $color->set("#C0C0FF"); # html color specification

         ($red, $green, $blue, $alpha) = $color->rgba();
         @hsv = $color->hsv();

         $color->info();

         if ($color->equals(other=>$other_color)) {
           ...
         }

DESCRIPTION

       This module handles creating color objects used by Imager.  The idea is that in the future
       this module will be able to handle color space calculations as well.

       An Imager color consists of up to four components, each in the range 0 to 255.
       Unfortunately the meaning of the components can change depending on the type of image
       you're dealing with:

       •   for 3 or 4 channel images the color components are red, green, blue, alpha.

       •   for 1 or 2 channel images the color components are gray, alpha, with the other two
           components ignored.

       An alpha value of zero is fully transparent, an alpha value of 255 is fully opaque.

METHODS

       new This creates a color object to pass to functions that need a color argument.

       set This changes an already defined color.  Note that this does not affect any places
           where the color has been used previously.

       rgba()
           This returns the red, green, blue and alpha channels of the color the object contains.

       info
           Calling info merely dumps the relevant color to the log.

       equals(other=>$other_color)
       equals(other=>$other_color, ignore_alpha=>1)
           Compares $self and color $other_color returning true if the color components are the
           same.

           Compares all four channels unless "ignore_alpha" is set.  If "ignore_alpha" is set
           only the first three channels are compared.

       You can specify colors in several different ways, you can just supply simple values:

       •   an Imager::Color object

       •   an Imager::Color::Float object, the ranges of samples are translated from 0.0...1.0 to
           0...255.

       •   simple numeric parameters - if you supply 3 or 4 numeric arguments, you get a color
           made up of those RGB (and possibly A) components.

       •   a six hex digit web color, either "RRGGBB" or "#RRGGBB"

       •   an eight hex digit web color, either "RRGGBBAA" or "#RRGGBBAA".

       •   a CSS rgb() color, based on CSS Color 4.  The "none" keyword is not supported and
           numbers must be simple decimals without exponents. eg.

             rgb(50% 50% 100%)
             rgb(0, 0, 255)
             rgb(0.5 0.5 1.0 / 0.8)
             rgb(50%, 50%, 100%, 80%)

           Samples from percentages or decimals are rounded up per CSS Color 3 and 4.

           This accepts some colors not accepted by the CSS rgb() specification, this may change.

       •   a 3 hex digit web color, "#RGB" - a value of F becomes 255.

       •   a color name, from whichever of the gimp "Named_Colors" file or X "rgb.txt" is found
           first.  The same as using the "name" keyword.

       You can supply named parameters:

       •   'red', 'green' and 'blue', optionally shortened to 'r', 'g' and 'b'.  The color
           components in the range 0 to 255.

            # all of the following are equivalent
            my $c1 = Imager::Color->new(red=>100, blue=>255, green=>0);
            my $c2 = Imager::Color->new(r=>100, b=>255, g=>0);
            my $c3 = Imager::Color->new(r=>100, blue=>255, g=>0);

       •   "hue", "saturation" and "value", optionally shortened to "h", "s" and "v", to specify
           a HSV color.  0 <= hue < 360, 0 <= s <= 1 and 0 <= v <= 1.

             # the same as RGB(127,255,127)
             my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5);
             my $c1 = Imager::Color->new(hue=>120, value=>1, saturation=>0.5);

       •   "web", which can specify a 6 or 3 hex digit web color, in any of the forms "#RRGGBB",
           "#RGB", "RRGGBB" or "RGB".

             my $c1 = Imager::Color->new(web=>'#FFC0C0'); # pale red

       •   "gray" or "grey" which specifies a single channel, from 0 to 255.

             # exactly the same
             my $c1 = Imager::Color->new(gray=>128);
             my $c1 = Imager::Color->new(grey=>128);

       •   "rgb" which takes a 3 member arrayref, containing each of the red, green and blue
           values.

             # the same
             my $c1 = Imager::Color->new(rgb=>[255, 100, 0]);
             my $c1 = Imager::Color->new(r=>255, g=>100, b=>0);

       •   "hsv" which takes a 3 member arrayref, containing each of hue, saturation and value.

             # the same
             my $c1 = Imager::Color->new(hsv=>[120, 0.5, 1]);
             my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5);

       •   "gimp" which specifies a color from a GIMP palette file.  You can specify the file
           name of the palette file with the 'palette' parameter, or let Imager::Color look in
           various places, typically "$HOME/gimp-1.x/palettes/Named_Colors" with and without the
           version number, and in "/usr/share/gimp/palettes/".  The palette file must have color
           names.

             my $c1 = Imager::Color->new(gimp=>'snow');
             my $c1 = Imager::Color->new(gimp=>'snow', palette=>'testimg/test_gimp_pal);

       •   "xname" which specifies a color from an X11 "rgb.txt" file.  You can specify the file
           name of the "rgb.txt" file with the "palette" parameter, or let Imager::Color look in
           various places, typically "/usr/lib/X11/rgb.txt".

             my $c1 = Imager::Color->new(xname=>'blue') # usually RGB(0, 0, 255)

       •   "builtin" which specifies a color from the built-in color table in
           Imager::Color::Table.  The colors in this module are the same as the default X11
           "rgb.txt" file.

             my $c1 = Imager::Color->new(builtin=>'black') # always RGB(0, 0, 0)

       •   "name" which specifies a name from either a GIMP palette, an X "rgb.txt" file or the
           built-in color table, whichever is found first.

       •   'channel0', 'channel1', etc, each of which specifies a single channel.  These can be
           abbreviated to 'c0', 'c1' etc.

       •   'channels' which takes an arrayref of the channel values.

       Optionally you can add an alpha channel to a color with the 'alpha' or 'a' parameter.

       These color specifications can be used for both constructing new colors with the new()
       method and modifying existing colors with the set() method.

METHODS

       hsv()
               my($h, $s, $v, $alpha) = $color->hsv();

           Returns the color as a Hue/Saturation/Value/Alpha tuple.

       red
       green
       blue
       alpha
           Returns the respective component as an integer from 0 to 255.

       as_float
           Returns the color as a Imager::Color::Float object.

       as_css_rgb
           Returns the color as a CSS rgb() format color.  This is always returned in the byte
           form, eg. rgb(255 128 64).

           If the alpha is not full coverage (255) it will be rounded if the result of converting
           the color back to an 8 bit color would return the same alpha, eg. if the color alpha
           is 128, it will be formatted as 0.5, not as the more precise 50.2%.

AUTHOR

       Arnar M. Hrafnkelsson, addi@umich.edu And a great deal of help from others - see the
       "README" for a complete list.

SEE ALSO

       Imager(3), Imager::Color http://imager.perl.org/