Manual Reference Pages - CONVERT::COLOR::RGB8 (3)
"Convert::Color::RGB8" - a color value represented as red/green/blue in 8-bit
my $red = Convert::Color::RGB8->new( 255, 0, 0 );
# Can also parse strings
my $pink = Convert::Color::RGB8->new( 255,192,192 );
$pink = Convert::Color::RGB8->new( ffc0c0 );
my $cyan = Convert::Color->new( rgb8:0,255,255 );
Objects in this class represent a color in RGB space, as a set of three
integer values in the range 0 to 255; i.e. as 8 bits.
For representations using floating point values, see Convert::Color::RGB.
For representations using 16-bit integers, see Convert::Color::RGB16.
CW$color = Convert::Color::RGB8->new( CW$red, CW$green, CW$blue )
Returns a new object to represent the set of values given. These values should
be integers between 0 and 255. Values outside of this range will be clamped.
CW$color = Convert::Color::RGB8->new( CW$string )
Parses $string for values, and construct a new object similar to the above
three-argument form. The string should be in the form
containing the three integer values in decimal notation. It can also be given
in the form of a hex encoded string, such as would be returned by the
CW$r = CW$color->red
CW$g = CW$color->green
CW$b = CW$color->blue
Accessors for the three components of the color.
( CW$red, CW$green, CW$blue ) = CW$color->rgb8
Returns the individual red, green and blue color components of the color
value in RGB8 space.
CW$str = CW$color->hex
Returns a string representation of the color components in the RGB8 space, in
a convenient RRGGBB hex string, likely to be useful HTML, or other similar
CW$mix = CW$color->alpha_blend( CW$other, [ CW$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 $other.
CW$mix = CW$color->alpha8_blend( CW$other, [ CW$alpha ] )
Similar to alpha_blend but works with integer arithmetic. $alpha should
be an integer in the range 0 to 255.
CW$measure = CW$color->dst_rgb8( CW$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.
CW$measure = CW$color->dst_rgb8_cheap( CW$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.
Paul Evans <firstname.lastname@example.org>
|perl v5.20.3 ||CONVERT::COLOR::RGB8 (3) ||2014-06-01 |
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