Convert::Color(3pm)					User Contributed Perl Documentation				       Convert::Color(3pm)

NAME

       "Convert::Color" - color space conversions and named lookups

SYNOPSIS

	use Convert::Color;

	my $color = Convert::Color->new( 'hsv:76,0.43,0.89' );

	my ( $red, $green, $blue ) = $color->rgb;

	# GTK uses 16-bit values
	my $gtk_col = Gtk2::Gdk::Color->new( $color->as_rgb16->rgb16 );

	# HTML uses #rrggbb in hex
	my $html = '<td bgcolor="#' . $color->as_rgb8->hex . '">';

DESCRIPTION

       This module provides conversions between commonly used ways to express colors.  It provides conversions between color spaces such as RGB
       and HSV, and it provides ways to look up colors by a name.

       This class provides a base for subclasses which represent particular color values in particular spaces. The base class provides methods to
       represent the color in a few convenient forms, though subclasses may provide more specific details for the space in question.

       For more detail, read the documentation on these classes; namely:

       o   Convert::Color::RGB - red/green/blue as floats between 0 and 1

       o   Convert::Color::RGB8 - red/green/blue as 8-bit integers

       o   Convert::Color::RGB16 - red/green/blue as 16-bit integers

       o   Convert::Color::HSV - hue/saturation/value

       o   Convert::Color::HSL - hue/saturation/lightness

       o   Convert::Color::CMY - cyan/magenta/yellow

       o   Convert::Color::CMYK - cyan/magenta/yellow/key (blackness)

       The following classes are subclasses of one of the above, which provide a way to access predefined colors by names:

       o   Convert::Color::VGA - named lookup for the basic VGA colors

       o   Convert::Color::X11 - named lookup of colors from X11's rgb.txt

CONSTRUCTOR

   $color = Convert::Color->new( STRING )
       Return a new value to represent the color specified by the string. This string should be prefixed by the name of the color space to which
       it applies. For example

	rgb:RED,GREEN,BLUE
	rgb8:RRGGBB
	rgb16:RRRRGGGGBBBB
	hsv:HUE,SAT,VAL
	hsl:HUE,SAT,LUM
	cmy:CYAN,MAGENTA,YELLOW
	cmyk:CYAN,MAGENTA,YELLOW,KEY

	vga:NAME
	vga:INDEX

	x11:NAME

       For more detail, see the constructor of the color space subclass in question.

METHODS

   ( $red, $green, $blue ) = $color->rgb
       Returns the individual red, green and blue color components of the color value. For RGB values, this is done directly. For values in other
       spaces, this is done by first converting them to an RGB value using their "to_rgb()" method.

COLOR SPACE CONVERSIONS

       Cross-conversion between color spaces is provided by the "convert_to()" method, assisted by helper methods in the two color space classes
       involved.

       When converting $color from color space SRC to color space DEST, the following operations are attemped, in this order. SRC and DEST refer
       to the names of the color spaces, e.g. "rgb".

       1.  If SRC and DEST are equal, return $color as it stands.

       2.  If the SRC space's class provides a "convert_to_DEST" method, use it.

       3.  If the DEST space's class provides a "new_from_SRC" constructor, call it and pass $color.

       4.  If the DEST space's class provides a "new_rgb" constructor, convert $color to red/green/blue components then call it.

       5.  If none of these operations worked, then throw an exception.

       These functions may be called in the following ways:

	$other = $color->convert_to_DEST()
	$other = Dest::Class->new_from_SRC( $color )
	$other = Dest::Class->new_rgb( $color->rgb )

   $other = $color->convert_to( $space )
       Attempt to convert the color into its representation in the given space. See above for the various ways this may be achieved.

       If the relevant subclass has already been loaded (either explicitly, or implicitly by either the "new" or "convert_to" methods), then a
       specific conversion method will be installed in the class.

	$other = $color->as_$space

       Methods of this form are currently "AUTOLOAD"ed if they do not yet exist, but this feature should not be relied upon - see below.

AUTOLOADED CONVERSION METHODS

       This class provides "AUTOLOAD" and "can" behaviour which automatically constructs conversion methods. The following method calls are
       identical:

	$color->convert_to('rgb')
	$color->as_rgb

       The generated method will be stored in the package, so that future calls will not have the AUTOLOAD overhead.

       This feature is deprecated and should not be relied upon, due to the delicate nature of "AUTOLOAD".

OTHER METHODS

       As well as the above, it is likely the subclass will provide accessors to directly obtain the components of its representation in the
       specific space.	For more detail, see the documentation for the specific subclass in question.

SUBCLASS METHODS

       This base class is intended to be subclassed to provide more color spaces.

   $class->register_color_space( $space )
       A subclass should call this method to register itself as a named color space.

   $class->register_palette( %args )
       A subclass that provides a fixed set of color values should call this method, to set up automatic conversions that look for the closest
       match within the set. This conversion process is controlled by the %args:

       enumerate => STRING or CODE
	       A method name or anonymous CODE reference which will be used to generate the list of color values.

       enumerate_once => STRING or CODE
	       As per "enumerate", but will be called only once and the results cached.

       This conversion process only finds the closest match in RGB space, so it may not give exact results.

       In the case of a tie, where two or more colors have the same distance from the target, the first one will be chosen.

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>

perl v5.12.3							    2011-06-15						       Convert::Color(3pm)