++ed by:
Paul Evans

NAME

Convert::Color::RGB8 - a color value represented as red/green/blue in 8-bit integers

SYNOPSIS

Directly:

 use Convert::Color::RGB8;

 my $red = Convert::Color::RGB8->new( 255, 0, 0 );

 # Can also parse strings
 my $pink = Convert::Color::RGB8->new( '255,192,192' );

 # or
 $pink = Convert::Color::RGB8->new( 'ffc0c0' );

Via Convert::Color:

 use Convert::Color;

 my $cyan = Convert::Color->new( 'rgb8:0,255,255' );

DESCRIPTION

Objects in this class represent a color in RGB space, as a set of three integer values in the range 0 to 255; i.e. as 8 bits.

For representations using floating point values, see Convert::Color::RGB. For representations using 16-bit integers, see Convert::Color::RGB16.

CONSTRUCTOR

$color = Convert::Color::RGB8->new( $red, $green, $blue )

Returns a new object to represent the set of values given. These values should be integers between 0 and 255. Values outside of this range will be clamped.

$color = Convert::Color::RGB8->new( $string )

Parses $string for values, and construct a new object similar to the above three-argument form. The string should be in the form

 red,green,blue

containing the three integer values in decimal notation. It can also be given in the form of a hex encoded string, such as would be returned by the rgb8_hex method:

 rrggbb

METHODS

$r = $color->red

$g = $color->green

$b = $color->blue

Accessors for the three components of the color.

( $red, $green, $blue ) = $color->rgb8

Returns the individual red, green and blue color components of the color value in RGB8 space.

$str = $color->hex

Returns a string representation of the color components in the RGB8 space, in a convenient RRGGBB hex string, likely to be useful HTML, or other similar places.

$mix = $color->alpha_blend( $other, [ $alpha ] )

Return a new color which is a blended combination of the two passed into it. The optional $alpha parameter defines the mix ratio between the two colors, defaulting to 0.5 if not defined. Values closer to 0 will blend more of $color, closer to 1 will blend more of $other.

$mix = $color->alpha8_blend( $other, [ $alpha ] )

Similar to alpha_blend but works with integer arithmetic. $alpha should be an integer in the range 0 to 255.

$measure = $color->dst_rgb8( $other )

Return a measure of the distance between the two colors. This is the unweighted Euclidean distance of the three color components. Two identical colors will have a measure of 0, pure black and pure white have a distance of 1, and all others will lie somewhere inbetween.

$measure = $color->dst_rgb8_cheap( $other )

Return a measure of the distance between the two colors. This is the sum of the squares of the differences of each of the color components. This is part of the value used to calculate dst_rgb8, but since it involves no square root it will be cheaper to calculate, for use in cases where only the relative values matter, such as when picking the "best match" out of a set of colors. It ranges between 0 for identical colours and 3*(255^2) for the distance between pure black and pure white.

SEE ALSO

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>




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