Convert::Color::RGB(3)User Contributed Perl DocumentatioConvert::Color::RGB(3)NAME
"Convert::Color::RGB" - a color value represented as red/green/blue
SYNOPSIS
Directly:
use Convert::Color::RGB;
my $red = Convert::Color::RGB->new( 1, 0, 0 );
# Can also parse strings
my $pink = Convert::Color::RGB->new( '1,0.7,0.7' );
Via Convert::Color:
use Convert::Color;
my $cyan = Convert::Color->new( 'rgb:0,1,1' );
DESCRIPTION
Objects in this class represent a color in RGB space, as a set of three
floating-point values in the range 0 to 1.
For representations using 8- or 16-bit integers, see
Convert::Color::RGB8 and Convert::Color::RGB16.
CONSTRUCTOR
$color = Convert::Color::RGB->new( $red, $green, $blue )
Returns a new object to represent the set of values given. These values
should be floating-point numbers between 0 and 1. Values outside of
this range will be clamped.
$color = Convert::Color::RGB->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 floating-point values in decimal notation.
METHODS
$r = $color->red
$g = $color->green
$b = $color->blue
Accessors for the three components of the color.
( $red, $green, $blue ) = $color->rgb
Returns the individual red, green and blue color components of the
color value.
$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.
$measure = $color->dst_rgb( $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_rgb_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_rgb", 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 for the distance between pure black and pure white.
EXAMPLES
Generating Gradients
The "alpha_blend" method can be used to generate a smooth gradient
between two colours.
use Convert::Color;
my $blue = Convert::Color->new("vga:blue");
my $cyan = Convert::Color->new("vga:cyan");
say $blue->alpha_blend( $cyan, $_/10 )->as_rgb8->hex for 0 .. 10
SEE ALSO
· Convert::Color - color space conversions
· Convert::Color::HSV - a color value represented as
hue/saturation/value
· Convert::Color::HSL - a color value represented as
hue/saturation/lightness
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.18.2 2014-05-13 Convert::Color::RGB(3)