NAME

NAME
Acme::Colour - additive and subtractive human-readable colours

SYNOPSIS
# light
$c = Acme::Colour->new("black");
$colour = $c->colour; # black
$c->add("red"); # $c->colour now red
$c->add("green"); # $c->colour now yellow

# pigment
$c = Acme::Colour->new("white");
$c->mix("cyan"); # $c->colour now cyan
$c->mix("magenta"); # $c->colour now blue

DESCRIPTION
The Acme::Colour module mixes colours with human-readable names.

There are two types of colour mixing: the mixing of lights and the
mixing of pigments. If one take two differently coloured beams of light
and projects them on to a screen, the mixing of these lights occurs
according to the principle of additive colour mixing. If one mixes two
differently coloured paints they mix according to the principle of
subtractive colour mixing.

METHODS
new()
The new() method creates a new colour. It takes an optional argument
which is the initial colour used:

$c = Acme::Colour->new("black");

colour()
The colour() method returns the current colour. Note that
stringification of the colour object magically returns the colour too:

$colour = $c->colour; # black
print "The colour is $c!\n";

add()
The add() method performs additive mixing on the colour. It takes in the
colour to add in:

$c->add("red");

mix()
The mix() method performs subtractive mixing on the colour. It takes in
the colour to mix in:

$c->mix("cyan");

ALTERNATIVE INTERFACE
There is an alternative interface to this module which overloads string
quoting. This is very cute, but is not recommended in production code.
Strings containing colour names magically get converted into
Acme::Colour objects and additive and subtractive mixing is performed on
these "strings" using "+" and "-":

use Acme::Colour constants => 1; # note special invocation

my $red = "red"; # now an Acme::Colour object
my $green = "green"; # likewise
my $yellow = $red + $green; # add()s the two colours

my $cyan = "cyan"; # now an Acme::Colour object
my $magenta = "magenta"; # likewise
my $blue = $cyan - $magenta; # mix()es the two colours

NOTES
A good explanation of colour and colour mixing is available at:
http://www.photoshopfocus.com/cool_tips/tips_color_basics_p1.htm

This module throws an exception upon unknown colours.

No, "colour" is not a typo.

AUTHOR
Leon Brocard <[email protected]>

COPYRIGHT
Copyright (C) 2002-3, Leon Brocard

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