Convert::Color::RGB8(3User Contributed Perl DocumentatiConvert::Color::RGB8(3)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
ยท Convert::Color - color space conversions
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.14.0 2011-06-19 Convert::Color::RGB8(3)