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/**
* Copyright: Mike Wey 2011
* License: zlib (See accompanying LICENSE file)
* Authors: Mike Wey
*/
module dmagick.ColorCMYK;
import std.algorithm;
import dmagick.Color;
import dmagick.c.magickType;
import dmagick.c.quantum;
/**
* The CMY(K) color model describes a color space with subtractive color
* composition as it is used for the color printing process, e.g. used by
* ink or laser printers. Each color is described by the color components
* cyan (C), magenta (M) and yellow (Y). The additional component black (K)
* is used for better gray and black reproduction.
*
* Note: This class doesn't use ICC or ICM profiles for the converson of
* CMYK to RGB.
*/
class ColorCMYK : Color
{
this()
{
super();
}
/**
* Create a CMYK Color from the specified doubles.
*/
this(double cyan, double magenta, double yellow, double black)
{
Quantum red, green, blue;
convertCMYKToRGB(cyan, magenta, yellow, black, red, green, blue);
super(red, green, blue);
}
/**
* The value for cyan.
*/
void cyan(double cyan)
{
double oldCyan, magenta, yellow, black;
convertRGBToCMYK(packet.red, packet.green, packet.blue, oldCyan, magenta, yellow, black);
convertCMYKToRGB(cyan, magenta, yellow, black, packet.red, packet.green, packet.blue);
}
///ditto
double cyan()
{
double cyan, magenta, yellow, black;
convertRGBToCMYK(packet.red, packet.green, packet.blue, cyan, magenta, yellow, black);
return cyan;
}
/**
* The value for magenta.
*/
void magenta(double magenta)
{
double cyan, oldMagenta, yellow, black;
convertRGBToCMYK(packet.red, packet.green, packet.blue, cyan, oldMagenta, yellow, black);
convertCMYKToRGB(cyan, magenta, yellow, black, packet.red, packet.green, packet.blue);
}
///ditto
double magenta()
{
double cyan, magenta, yellow, black;
convertRGBToCMYK(packet.red, packet.green, packet.blue, cyan, magenta, yellow, black);
return magenta;
}
/**
* The value for yellow.
*/
void yellow(double yellow)
{
double cyan, magenta, oldYellow, black;
convertRGBToCMYK(packet.red, packet.green, packet.blue, cyan, magenta, oldYellow, black);
convertCMYKToRGB(cyan, magenta, yellow, black, packet.red, packet.green, packet.blue);
}
///ditto
double yellow()
{
double cyan, magenta, yellow, black;
convertRGBToCMYK(packet.red, packet.green, packet.blue, cyan, magenta, yellow, black);
return yellow;
}
/**
* The value for black.
*/
void black(double black)
{
double cyan, magenta, yellow, oldBlack;
convertRGBToCMYK(packet.red, packet.green, packet.blue, cyan, magenta, yellow, oldBlack);
convertCMYKToRGB(cyan, magenta, yellow, black, packet.red, packet.green, packet.blue);
}
///ditto
double black()
{
double cyan, magenta, yellow, black;
convertRGBToCMYK(packet.red, packet.green, packet.blue, cyan, magenta, yellow, black);
return black;
}
/**
* Convert an RGB value to a CMYK value.
*/
private void convertRGBToCMYK(Quantum red, Quantum green, Quantum blue, ref double cyan, ref double magenta, ref double yellow, ref double black)
{
double r = scaleQuantumToDouble(red);
double g = scaleQuantumToDouble(green);
double b = scaleQuantumToDouble(blue);
black = min(1 - r, 1 - g, 1 - b);
cyan = (1 - r - black) / (1 - black);
magenta = (1 - g - black) / (1 - black);
yellow = (1 - b - black) / (1 - black);
}
/**
* Convert an CMYK value to a RGB value.
*/
private void convertCMYKToRGB(double cyan, double magenta, double yellow, double black, ref Quantum red, ref Quantum green, ref Quantum blue)
in
{
assert(cyan <= 1 && cyan >= 0);
assert(magenta <= 1 && magenta >= 0);
assert(yellow <= 1 && yellow >= 0);
assert(black <= 1 && black >= 0);
}
body
{
double r = 1 - min(1, cyan * (1 - black) + black);
double g = 1 - min(1, magenta * (1 - black) + black);
double b = 1 - min(1, yellow * (1 - black) + black);
red = scaleDoubleToQuantum(r);
green = scaleDoubleToQuantum(g);
blue = scaleDoubleToQuantum(b);
}
}
unittest
{
assert(new ColorCMYK(0, 1, 1, 0 ) == new Color("red"));
auto color1 = new ColorCMYK(0.5, 0.5, 0.5, 0.5);
auto color2 = new Color("gray25");
//Compare the colors a bytes, to compensate for rounding errors.
assert(ScaleQuantumToChar(color1.redQuantum) == ScaleQuantumToChar(color2.redQuantum));
assert(ScaleQuantumToChar(color1.greenQuantum) == ScaleQuantumToChar(color2.greenQuantum));
assert(ScaleQuantumToChar(color1.blueQuantum) == ScaleQuantumToChar(color2.blueQuantum));
}
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