convert::color::rgb16(3pm) [debian man page]
Convert::Color::RGB16(3pm) User Contributed Perl Documentation Convert::Color::RGB16(3pm) NAME
"Convert::Color::RGB16" - a color value represented as red/green/blue in 16-bit integers SYNOPSIS
Directly: use Convert::Color::RGB16; my $red = Convert::Color::RGB16->new( 65535, 0, 0 ); # Can also parse strings my $pink = Convert::Color::RGB16->new( '65535,49152,49152' ); # or $pink = Convert::Color::RGB16->new( 'ffffc000c000' ); Via Convert::Color: use Convert::Color; my $cyan = Convert::Color->new( 'rgb16:0,65535,65535' ); DESCRIPTION
Objects in this class represent a color in RGB space, as a set of three integer values in the range 0 to 65535; i.e. as 16 bits. For representations using floating point values, see Convert::Color::RGB. For representations using 8-bit integers, see Convert::Color::RGB8. CONSTRUCTOR
$color = Convert::Color::RGB16->new( $red, $green, $blue ) Returns a new object to represent the set of values given. These values should be integers between 0 and 65535. Values outside of this range will be clamped. $color = Convert::Color::RGB16->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 "rgb16_hex" method: rrrrggggbbbb METHODS
$r = $color->red $g = $color->green $b = $color->blue Accessors for the three components of the color. ( $red, $green, $blue ) = $color->rgb16 Returns the individual red, green and blue color components of the color value in RGB16 space. $str = $color->hex Returns a string representation of the color components in the RGB16 space, in a convenient "RRRRGGGGBBBB" hex string. $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->alpha16_blend( $other, [ $alpha ] ) Similar to "alpha_blend" but works with integer arithmetic. $alpha should be an integer in the range 0 to 65535. $measure = $color->dst_rgb16( $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_rgb16_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_rgb16", 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*(65535^2) for the distance between pure black and pure white. SEE ALSO
o Convert::Color - color space conversions AUTHOR
Paul Evans <leonerd@leonerd.org.uk> perl v5.12.3 2011-06-15 Convert::Color::RGB16(3pm)
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Imager::Color(3pm) User Contributed Perl Documentation Imager::Color(3pm) NAME
Imager::Color - Color handling for Imager. SYNOPSIS
use Imager; $color = Imager::Color->new($red, $green, $blue); $color = Imager::Color->new($red, $green, $blue, $alpha); $color = Imager::Color->new("#C0C0FF"); # html color specification $color->set($red, $green, $blue); $color->set($red, $green, $blue, $alpha); $color->set("#C0C0FF"); # html color specification ($red, $green, $blue, $alpha) = $color->rgba(); @hsv = $color->hsv(); $color->info(); if ($color->equals(other=>$other_color)) { ... } DESCRIPTION
This module handles creating color objects used by Imager. The idea is that in the future this module will be able to handle color space calculations as well. An Imager color consists of up to four components, each in the range 0 to 255. Unfortunately the meaning of the components can change depending on the type of image you're dealing with: o for 3 or 4 channel images the color components are red, green, blue, alpha. o for 1 or 2 channel images the color components are gray, alpha, with the other two components ignored. An alpha value of zero is fully transparent, an alpha value of 255 is fully opaque. METHODS
new This creates a color object to pass to functions that need a color argument. set This changes an already defined color. Note that this does not affect any places where the color has been used previously. rgba() This returns the red, green, blue and alpha channels of the color the object contains. info Calling info merely dumps the relevant color to the log. equals(other=>$other_color) equals(other=>$other_color, ignore_alpha=>1) Compares $self and color $other_color returning true if the color components are the same. Compares all four channels unless "ignore_alpha" is set. If "ignore_alpha" is set only the first three channels are compared. You can specify colors in several different ways, you can just supply simple values: o simple numeric parameters - if you supply 3 or 4 numeric arguments, you get a color made up of those RGB (and possibly A) components. o a six hex digit web color, either "RRGGBB" or "#RRGGBB" o an eight hex digit web color, either "RRGGBBAA" or "#RRGGBBAA". o a 3 hex digit web color, "#RGB" - a value of F becomes 255. o a color name, from whichever of the gimp "Named_Colors" file or X "rgb.txt" is found first. The same as using the "name" keyword. You can supply named parameters: o 'red', 'green' and 'blue', optionally shortened to 'r', 'g' and 'b'. The color components in the range 0 to 255. # all of the following are equivalent my $c1 = Imager::Color->new(red=>100, blue=>255, green=>0); my $c2 = Imager::Color->new(r=>100, b=>255, g=>0); my $c3 = Imager::Color->new(r=>100, blue=>255, g=>0); o "hue", "saturation" and "value", optionally shortened to "h", "s" and "v", to specify a HSV color. 0 <= hue < 360, 0 <= s <= 1 and 0 <= v <= 1. # the same as RGB(127,255,127) my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5); my $c1 = Imager::Color->new(hue=>120, value=>1, saturation=>0.5); o "web", which can specify a 6 or 3 hex digit web color, in any of the forms "#RRGGBB", "#RGB", "RRGGBB" or "RGB". my $c1 = Imager::Color->new(web=>'#FFC0C0'); # pale red o "gray" or "grey" which specifies a single channel, from 0 to 255. # exactly the same my $c1 = Imager::Color->new(gray=>128); my $c1 = Imager::Color->new(grey=>128); o "rgb" which takes a 3 member arrayref, containing each of the red, green and blue values. # the same my $c1 = Imager::Color->new(rgb=>[255, 100, 0]); my $c1 = Imager::Color->new(r=>255, g=>100, b=>0); o "hsv" which takes a 3 member arrayref, containing each of hue, saturation and value. # the same my $c1 = Imager::Color->new(hsv=>[120, 0.5, 1]); my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5); o "gimp" which specifies a color from a GIMP palette file. You can specify the file name of the palette file with the 'palette' parameter, or let Imager::Color look in various places, typically "$HOME/gimp-1.x/palettes/Named_Colors" with and without the version number, and in "/usr/share/gimp/palettes/". The palette file must have color names. my $c1 = Imager::Color->new(gimp=>'snow'); my $c1 = Imager::Color->new(gimp=>'snow', palette=>'testimg/test_gimp_pal); o "xname" which specifies a color from an X11 "rgb.txt" file. You can specify the file name of the "rgb.txt" file with the "palette" parameter, or let Imager::Color look in various places, typically "/usr/lib/X11/rgb.txt". my $c1 = Imager::Color->new(xname=>'blue') # usually RGB(0, 0, 255) o "builtin" which specifies a color from the built-in color table in Imager::Color::Table. The colors in this module are the same as the default X11 "rgb.txt" file. my $c1 = Imager::Color->new(builtin=>'black') # always RGB(0, 0, 0) o "name" which specifies a name from either a GIMP palette, an X "rgb.txt" file or the built-in color table, whichever is found first. o 'channel0', 'channel1', etc, each of which specifies a single channel. These can be abbreviated to 'c0', 'c1' etc. o 'channels' which takes an arrayref of the channel values. Optionally you can add an alpha channel to a color with the 'alpha' or 'a' parameter. These color specifications can be used for both constructing new colors with the new() method and modifying existing colors with the set() method. METHODS
hsv() my($h, $s, $v, $alpha) = $color->hsv(); Returns the color as a Hue/Saturation/Value/Alpha tuple. AUTHOR
Arnar M. Hrafnkelsson, addi@umich.edu And a great deal of help from others - see the "README" for a complete list. SEE ALSO
Imager(3), Imager::Color http://imager.perl.org/ perl v5.14.2 2011-06-06 Imager::Color(3pm)