image/lib/src/color.dart - third_party/dart-pkg - Git at Google

 import 'dart:math' as Math;

 import 'image_exception.dart';
 import 'internal/clamp.dart';

 /**
  * Image pixel colors are instantiated as an int object rather than an instance
  * of the Color class in order to reduce object allocations. Image pixels are
  * stored in 32-bit RGBA format (8 bits per channel). Internally in dart, this
  * will be stored in a "small integer" on 64-bit machines, or a
  * "medium integer" on 32-bit machines. In Javascript, this will be stored
  * in a 64-bit double.
  *
  * The Color class is used as a namespace for color operations, in an attempt
  * to create a cleaner API for color operations.
  */
 class Color {
   /**
    * Create a color value from RGB values in the range [0, 255].
    */
   static int fromRgb(int red, int green, int blue) {
     return getColor(red, green, blue);
   }

   /**
    * Create a color value from RGBA values in the range [0, 255].
    */
   static int fromRgba(int red, int green, int blue, int alpha) {
     return getColor(red, green, blue, alpha);
   }

   /**
    * Create a color value from HSL values in the range [0, 1].
    */
   static int fromHsl(num hue, num saturation, num lightness) {
     var rgb = hslToRGB(hue, saturation, lightness);
     return getColor(rgb[0], rgb[1], rgb[2]);
   }

   /**
    * Create a color value from HSV values in the range [0, 1].
    */
   static int fromHsv(num hue, num saturation, num value) {
     var rgb = hsvToRGB(hue, saturation, value);
     return getColor(rgb[0], rgb[1], rgb[2]);
   }

   /**
    * Create a color value from XYZ values.
    */
   static int fromXyz(num x, num y, num z) {
     var rgb = xyzToRGB(x, y, z);
     return getColor(rgb[0], rgb[1], rgb[2]);
   }

   /**
    * Create a color value from CIE-L*ab values.
    */
   static int fromLab(num L, num a, num b) {
     var rgb = labToRGB(L, a, b);
     return getColor(rgb[0], rgb[1], rgb[2]);
   }
 }


 /// Red channel of a color.
 const int RED = 0;
 /// Green channel of a color.
 const int GREEN = 1;
 /// Blue channel of a color.
 const int BLUE = 2;
 /// Alpha channel of a color.
 const int ALPHA = 3;
 /// Luminance of a color.
 const int LUMINANCE = 4;

 /**
  * Get the color with the given [r], [g], [b], and [a] components.
  *
  * The channel order of a uint32 encoded color is RGBA, to be consistent
  * with the image data of a canvas html element.
  */
 int getColor(int r, int g, int b, [int a = 255]) =>
     (clamp255(a) << 24) |
     (clamp255(b) << 16) |
     (clamp255(g) << 8) |
     clamp255(r);

 /**
  * Get the [channel] from the [color].
  */
 int getChannel(int color, int channel) =>
     channel == 0 ? getRed(color) :
     channel == 1 ? getGreen(color) :
     channel == 2 ? getBlue(color) :
     getAlpha(color);

 /**
  * Returns a new color, where the given [color]'s [channel] has been
  * replaced with the given [value].
  */
 int setChannel(int color, int channel, int value) =>
     channel == 0 ? setRed(color, value) :
     channel == 1 ? setGreen(color, value) :
     channel == 2 ? setBlue(color, value) :
     setAlpha(color, value);

 /**
  * Get the red channel from the [color].
  */
 int getRed(int color) =>
     (color) & 0xff;

 /**
  * Returns a new color where the red channel of [color] has been replaced
  * by [value].
  */
 int setRed(int color, int value) =>
     (color & 0xffffff00) | (clamp255(value));

 /**
  * Get the green channel from the [color].
  */
 int getGreen(int color) =>
     (color >> 8) & 0xff;

 /**
  * Returns a new color where the green channel of [color] has been replaced
  * by [value].
  */
 int setGreen(int color, int value) =>
     (color & 0xffff00ff) | (clamp255(value) << 8);

 /**
  * Get the blue channel from the [color].
  */
 int getBlue(int color) =>
     (color >> 16) & 0xff;

 /**
  * Returns a new color where the blue channel of [color] has been replaced
  * by [value].
  */
 int setBlue(int color, int value) =>
     (color & 0xff00ffff) | (clamp255(value) << 16);

 /**
  * Get the alpha channel from the [color].
  */
 int getAlpha(int color) =>
     (color >> 24) & 0xff;

 /**
  * Returns a new color where the alpha channel of [color] has been replaced
  * by [value].
  */
 int setAlpha(int color, int value) =>
     (color & 0x00ffffff) | (clamp255(value) << 24);

 /**
  * Returns a new color of [src] alpha-blended onto [dst]. The opacity of [src]
  * is additionally scaled by [fraction] / 255.
  */
 int alphaBlendColors(int dst, int src, [int fraction = 0xff]) {
   double a = (getAlpha(src) / 255.0);
   if (fraction != 0xff) {
     a *= (fraction / 255.0);
   }

   int sr = (getRed(src) * a).round();
   int sg = (getGreen(src) * a).round();
   int sb = (getBlue(src) * a).round();
   int sa = (getAlpha(src) * a).round();

   int dr = (getRed(dst) * (1.0 - a)).round();
   int dg = (getGreen(dst) * (1.0 - a)).round();
   int db = (getBlue(dst) * (1.0 - a)).round();
   int da = (getAlpha(dst) * (1.0 - a)).round();

   return getColor(sr + dr, sg + dg, sb + db, sa + da);
 }

 /**
  * Returns the luminance (grayscale) value of the [color].
  */
 int getLuminance(int color) {
   int r = getRed(color);
   int g = getGreen(color);
   int b = getBlue(color);
   return (0.299 * r + 0.587 * g + 0.114 * b).round();
 }

 /**
  * Returns the luminance (grayscale) value of the color.
  */
 int getLuminanceRGB(int r, int g, int b) =>
   (0.299 * r + 0.587 * g + 0.114 * b).round();

 /**
  * Convert an HSL color to RGB, where h is specified in normalized degrees
  * [0, 1] (where 1 is 360-degrees); s and l are in the range [0, 1].
  * Returns a list [r, g, b] with values in the range [0, 255].
  */
 List<int> hslToRGB(num hue, num saturation, num lightness) {
   if (saturation == 0) {
     int gray = (lightness * 255.0).toInt();
     return [gray, gray, gray];
   }

   hue2rgb(num p, num q, num t) {
     if (t < 0.0) {
       t += 1.0;
     }
     if (t > 1) {
       t -= 1.0;
     }
     if (t < 1.0 / 6.0) {
       return p + (q - p) * 6.0 * t;
     }
     if (t < 1.0 / 2.0) {
       return q;
     }
     if (t < 2.0 / 3.0) {
       return p + (q - p) * (2.0/3.0 - t) * 6.0;
     }
     return p;
   }

   var q = lightness < 0.5
           ? lightness * (1.0 + saturation)
           : lightness + saturation - lightness * saturation;
   var p = 2.0 * lightness - q;

   var r = hue2rgb(p, q, hue + 1.0 / 3.0);
   var g = hue2rgb(p, q, hue);
   var b = hue2rgb(p, q, hue - 1.0 / 3.0);

   return [(r * 255.0).round(), (g * 255.0).round(), (b * 255.0).round()];
 }

 /**
  * Convert an HSV color to RGB, where h is specified in normalized degrees
  * [0, 1] (where 1 is 360-degrees); s and l are in the range [0, 1].
  * Returns a list [r, g, b] with values in the range [0, 255].
  */
 List<int> hsvToRGB(num hue, num saturation, num brightness) {
   if (saturation == 0) {
     var gray = (brightness * 255.0).round();
     return [gray, gray, gray];
   }

   double h = (hue - hue.floor()) * 6.0;
   double f = h - h.floor();
   double p = brightness * (1.0 - saturation);
   double q = brightness * (1.0 - saturation * f);
   double t = brightness * (1.0 - (saturation * (1.0 - f)));

   switch (h.toInt()) {
     case 0:
       return [(brightness * 255.0).round(),
               (t * 255.0).round(),
               (p * 255.0).round()];
     case 1:
       return [(q * 255.0).round(),
               (brightness * 255.0).round(),
               (p * 255.0).round()];
     case 2:
       return [(p * 255.0).round(),
               (brightness * 255.0).round(),
               (t * 255.0).round()];
     case 3:
       return [(p * 255.0).round(),
               (q * 255.0).round(),
               (brightness * 255.0).round()];
     case 4:
       return [(t * 255.0).round(),
               (p * 255.0).round(),
               (brightness * 255.0).round()];
     case 5:
       return [(brightness * 255.0).round(),
               (p * 255.0).round(),
               (q * 255.0).round()];
     default:
       throw new ImageException('invalid hue');
   }
 }

 /**
  * Convert an RGB color to HSL, where r, g and b are in the range [0, 255].
  * Returns a list [h, s, l] with values in the range [0, 1].
  */
 List<double> rgbToHSL(num r, num g, num b) {
   r /= 255.0;
   g /= 255.0;
   b /= 255.0;
   var max = Math.max(r, Math.max(g, b));
   var min = Math.min(r, Math.min(g, b));
   var h;
   var s;
   var l = (max + min) / 2.0;

   if (max == min){
     return [0.0, 0.0, l];
   }

   var d = max - min;

   s = l > 0.5 ? d / (2.0 - max - min) : d / (max + min);

   if (max == r) {
     h = (g - b) / d + (g < b ? 6.0 : 0.0);
   } else if (max == g) {
     h = (b - r) / d + 2.0;
   } else {
     h = (r - g) / d + 4.0;
   }

   h /= 6.0;

   return [h, s, l];
 }

 /**
  * Convert a CIE-L*ab color to XYZ.
  */
 List<int> labToXYZ(num l, num a, num b) {
   var y = (l + 16.0) / 116.0;
   var x = y + (a / 500.0);
   var z = y - (b / 200.0);
   if (Math.pow(x, 3) > 0.008856) {
     x = Math.pow(x, 3);
   } else {
     x = (x - 16.0 / 116) / 7.787;
   }
   if (Math.pow(y, 3) > 0.008856) {
     y = Math.pow(y, 3);
   } else {
     y = (y - 16.0 / 116.0) / 7.787;
   }
   if (Math.pow(z, 3) > 0.008856) {
     z = Math.pow(z, 3);
   } else {
     z = (z - 16.0 / 116.0) / 7.787;
   }

   return [(x * 95.047).toInt(), (y * 100.0).toInt(), (z * 108.883).toInt()];
 }

 /**
  * Convert an XYZ color to RGB.
  */
 List<int> xyzToRGB(num x, num y, num z) {
   var b, g, r;
   x /= 100;
   y /= 100;
   z /= 100;
   r = (3.2406 * x) + (-1.5372 * y) + (-0.4986 * z);
   g = (-0.9689 * x) + (1.8758 * y) + (0.0415 * z);
   b = (0.0557 * x) + (-0.2040 * y) + (1.0570 * z);
   if (r > 0.0031308) {
     r = (1.055 * Math.pow(r, 0.4166666667)) - 0.055;
   } else {
     r *= 12.92;
   }
   if (g > 0.0031308) {
     g = (1.055 * Math.pow(g, 0.4166666667)) - 0.055;
   } else {
     g *= 12.92;
   }
   if (b > 0.0031308) {
     b = (1.055 * Math.pow(b, 0.4166666667)) - 0.055;
   } else {
     b *= 12.92;
   }

   return [(r * 255).toInt().clamp(0, 255),
           (g * 255).toInt().clamp(0, 255),
           (b * 255).toInt().clamp(0, 255)];
 }

 /**
  * Convert a CMYK color to RGB, where c, m, y, k values are in the range
  * [0, 255]. Returns a list [r, g, b] with values in the range [0, 255].
  */
 List<int> cmykToRGB(num c, num m, num y, num k) {
   c /= 255.0;
   m /= 255.0;
   y /= 255.0;
   k /= 255.0;
   return [(255.0 * (1.0 - c) * (1.0 - k)).round(),
           (255.0 * (1.0 - m) * (1.0 - k)).round(),
           (255.0 * (1.0 - y) * (1.0 - k)).round()];
 }

 /**
  * Convert a CIE-L*ab color to RGB.
  */
 List<int> labToRGB(num l, num a, num b) {
   const double ref_x = 95.047;
   const double ref_y = 100.000;
   const double ref_z = 108.883;

   double y = (l + 16.0) / 116.0;
   double x = a / 500.0 + y;
   double z = y - b / 200.0;

   double y3 = Math.pow(y, 3);
   if (y3 > 0.008856) {
     y = y3;
   } else {
     y = (y - 16 / 116) / 7.787;
   }

   double x3 = Math.pow(x,  3);
   if (x3 > 0.008856) {
     x = x3;
   } else {
     x = (x - 16 / 116) / 7.787;
   }

   double z3 = Math.pow(z, 3);
   if (z3 > 0.008856) {
     z = z3;
   } else {
     z = (z - 16 / 116) / 7.787;
   }

   x *= ref_x;
   y *= ref_y;
   z *= ref_z;

   x /= 100.0;
   y /= 100.0;
   z /= 100.0;

   // xyz to rgb
   double R = x * 3.2406 + y * (-1.5372) + z * (-0.4986);
   double G = x * (-0.9689) + y * 1.8758 + z * 0.0415;
   double B = x * 0.0557 + y * (-0.2040) + z * 1.0570;

   if (R > 0.0031308) {
     R = 1.055 * (Math.pow(R, 1.0 / 2.4)) - 0.055;
   } else {
     R = 12.92 * R;
   }

   if (G > 0.0031308) {
     G = 1.055 * (Math.pow(G, 1.0 / 2.4)) - 0.055;
   } else {
     G = 12.92 * G;
   }

   if (B > 0.0031308) {
     B = 1.055 * (Math.pow(B, 1.0 / 2.4)) - 0.055;
   } else {
     B = 12.92 * B;
   }

   return [(R * 255.0).toInt().clamp(0,  255),
           (G * 255.0).toInt().clamp(0,  255),
           (B * 255.0).toInt().clamp(0,  255)];
 }
	import 'dart:math' as Math;

	import 'image_exception.dart';
	import 'internal/clamp.dart';

	/**
	* Image pixel colors are instantiated as an int object rather than an instance
	* of the Color class in order to reduce object allocations. Image pixels are
	* stored in 32-bit RGBA format (8 bits per channel). Internally in dart, this
	* will be stored in a "small integer" on 64-bit machines, or a
	* "medium integer" on 32-bit machines. In Javascript, this will be stored
	* in a 64-bit double.
	*
	* The Color class is used as a namespace for color operations, in an attempt
	* to create a cleaner API for color operations.
	*/
	class Color {
	/**
	* Create a color value from RGB values in the range [0, 255].
	*/
	static int fromRgb(int red, int green, int blue) {
	return getColor(red, green, blue);
	}

	/**
	* Create a color value from RGBA values in the range [0, 255].
	*/
	static int fromRgba(int red, int green, int blue, int alpha) {
	return getColor(red, green, blue, alpha);
	}

	/**
	* Create a color value from HSL values in the range [0, 1].
	*/
	static int fromHsl(num hue, num saturation, num lightness) {
	var rgb = hslToRGB(hue, saturation, lightness);
	return getColor(rgb[0], rgb[1], rgb[2]);
	}

	/**
	* Create a color value from HSV values in the range [0, 1].
	*/
	static int fromHsv(num hue, num saturation, num value) {
	var rgb = hsvToRGB(hue, saturation, value);
	return getColor(rgb[0], rgb[1], rgb[2]);
	}

	/**
	* Create a color value from XYZ values.
	*/
	static int fromXyz(num x, num y, num z) {
	var rgb = xyzToRGB(x, y, z);
	return getColor(rgb[0], rgb[1], rgb[2]);
	}

	/**
	* Create a color value from CIE-L*ab values.
	*/
	static int fromLab(num L, num a, num b) {
	var rgb = labToRGB(L, a, b);
	return getColor(rgb[0], rgb[1], rgb[2]);
	}
	}


	/// Red channel of a color.
	const int RED = 0;
	/// Green channel of a color.
	const int GREEN = 1;
	/// Blue channel of a color.
	const int BLUE = 2;
	/// Alpha channel of a color.
	const int ALPHA = 3;
	/// Luminance of a color.
	const int LUMINANCE = 4;

	/**
	* Get the color with the given [r], [g], [b], and [a] components.
	*
	* The channel order of a uint32 encoded color is RGBA, to be consistent
	* with the image data of a canvas html element.
	*/
	int getColor(int r, int g, int b, [int a = 255]) =>
	(clamp255(a) << 24) \|
	(clamp255(b) << 16) \|
	(clamp255(g) << 8) \|
	clamp255(r);

	/**
	* Get the [channel] from the [color].
	*/
	int getChannel(int color, int channel) =>
	channel == 0 ? getRed(color) :
	channel == 1 ? getGreen(color) :
	channel == 2 ? getBlue(color) :
	getAlpha(color);

	/**
	* Returns a new color, where the given [color]'s [channel] has been
	* replaced with the given [value].
	*/
	int setChannel(int color, int channel, int value) =>
	channel == 0 ? setRed(color, value) :
	channel == 1 ? setGreen(color, value) :
	channel == 2 ? setBlue(color, value) :
	setAlpha(color, value);

	/**
	* Get the red channel from the [color].
	*/
	int getRed(int color) =>
	(color) & 0xff;

	/**
	* Returns a new color where the red channel of [color] has been replaced
	* by [value].
	*/
	int setRed(int color, int value) =>
	(color & 0xffffff00) \| (clamp255(value));

	/**
	* Get the green channel from the [color].
	*/
	int getGreen(int color) =>
	(color >> 8) & 0xff;

	/**
	* Returns a new color where the green channel of [color] has been replaced
	* by [value].
	*/
	int setGreen(int color, int value) =>
	(color & 0xffff00ff) \| (clamp255(value) << 8);

	/**
	* Get the blue channel from the [color].
	*/
	int getBlue(int color) =>
	(color >> 16) & 0xff;

	/**
	* Returns a new color where the blue channel of [color] has been replaced
	* by [value].
	*/
	int setBlue(int color, int value) =>
	(color & 0xff00ffff) \| (clamp255(value) << 16);

	/**
	* Get the alpha channel from the [color].
	*/
	int getAlpha(int color) =>
	(color >> 24) & 0xff;

	/**
	* Returns a new color where the alpha channel of [color] has been replaced
	* by [value].
	*/
	int setAlpha(int color, int value) =>
	(color & 0x00ffffff) \| (clamp255(value) << 24);

	/**
	* Returns a new color of [src] alpha-blended onto [dst]. The opacity of [src]
	* is additionally scaled by [fraction] / 255.
	*/
	int alphaBlendColors(int dst, int src, [int fraction = 0xff]) {
	double a = (getAlpha(src) / 255.0);
	if (fraction != 0xff) {
	a *= (fraction / 255.0);
	}

	int sr = (getRed(src) * a).round();
	int sg = (getGreen(src) * a).round();
	int sb = (getBlue(src) * a).round();
	int sa = (getAlpha(src) * a).round();

	int dr = (getRed(dst) * (1.0 - a)).round();
	int dg = (getGreen(dst) * (1.0 - a)).round();
	int db = (getBlue(dst) * (1.0 - a)).round();
	int da = (getAlpha(dst) * (1.0 - a)).round();

	return getColor(sr + dr, sg + dg, sb + db, sa + da);
	}

	/**
	* Returns the luminance (grayscale) value of the [color].
	*/
	int getLuminance(int color) {
	int r = getRed(color);
	int g = getGreen(color);
	int b = getBlue(color);
	return (0.299 * r + 0.587 * g + 0.114 * b).round();
	}

	/**
	* Returns the luminance (grayscale) value of the color.
	*/
	int getLuminanceRGB(int r, int g, int b) =>
	(0.299 * r + 0.587 * g + 0.114 * b).round();

	/**
	* Convert an HSL color to RGB, where h is specified in normalized degrees
	* [0, 1] (where 1 is 360-degrees); s and l are in the range [0, 1].
	* Returns a list [r, g, b] with values in the range [0, 255].
	*/
	List<int> hslToRGB(num hue, num saturation, num lightness) {
	if (saturation == 0) {
	int gray = (lightness * 255.0).toInt();
	return [gray, gray, gray];
	}

	hue2rgb(num p, num q, num t) {
	if (t < 0.0) {
	t += 1.0;
	}
	if (t > 1) {
	t -= 1.0;
	}
	if (t < 1.0 / 6.0) {
	return p + (q - p) * 6.0 * t;
	}
	if (t < 1.0 / 2.0) {
	return q;
	}
	if (t < 2.0 / 3.0) {
	return p + (q - p) * (2.0/3.0 - t) * 6.0;
	}
	return p;
	}

	var q = lightness < 0.5
	? lightness * (1.0 + saturation)
	: lightness + saturation - lightness * saturation;
	var p = 2.0 * lightness - q;

	var r = hue2rgb(p, q, hue + 1.0 / 3.0);
	var g = hue2rgb(p, q, hue);
	var b = hue2rgb(p, q, hue - 1.0 / 3.0);

	return [(r * 255.0).round(), (g * 255.0).round(), (b * 255.0).round()];
	}

	/**
	* Convert an HSV color to RGB, where h is specified in normalized degrees
	* [0, 1] (where 1 is 360-degrees); s and l are in the range [0, 1].
	* Returns a list [r, g, b] with values in the range [0, 255].
	*/
	List<int> hsvToRGB(num hue, num saturation, num brightness) {
	if (saturation == 0) {
	var gray = (brightness * 255.0).round();
	return [gray, gray, gray];
	}

	double h = (hue - hue.floor()) * 6.0;
	double f = h - h.floor();
	double p = brightness * (1.0 - saturation);
	double q = brightness * (1.0 - saturation * f);
	double t = brightness * (1.0 - (saturation * (1.0 - f)));

	switch (h.toInt()) {
	case 0:
	return [(brightness * 255.0).round(),
	(t * 255.0).round(),
	(p * 255.0).round()];
	case 1:
	return [(q * 255.0).round(),
	(brightness * 255.0).round(),
	(p * 255.0).round()];
	case 2:
	return [(p * 255.0).round(),
	(brightness * 255.0).round(),
	(t * 255.0).round()];
	case 3:
	return [(p * 255.0).round(),
	(q * 255.0).round(),
	(brightness * 255.0).round()];
	case 4:
	return [(t * 255.0).round(),
	(p * 255.0).round(),
	(brightness * 255.0).round()];
	case 5:
	return [(brightness * 255.0).round(),
	(p * 255.0).round(),
	(q * 255.0).round()];
	default:
	throw new ImageException('invalid hue');
	}
	}

	/**
	* Convert an RGB color to HSL, where r, g and b are in the range [0, 255].
	* Returns a list [h, s, l] with values in the range [0, 1].
	*/
	List<double> rgbToHSL(num r, num g, num b) {
	r /= 255.0;
	g /= 255.0;
	b /= 255.0;
	var max = Math.max(r, Math.max(g, b));
	var min = Math.min(r, Math.min(g, b));
	var h;
	var s;
	var l = (max + min) / 2.0;

	if (max == min){
	return [0.0, 0.0, l];
	}

	var d = max - min;

	s = l > 0.5 ? d / (2.0 - max - min) : d / (max + min);

	if (max == r) {
	h = (g - b) / d + (g < b ? 6.0 : 0.0);
	} else if (max == g) {
	h = (b - r) / d + 2.0;
	} else {
	h = (r - g) / d + 4.0;
	}

	h /= 6.0;

	return [h, s, l];
	}

	/**
	* Convert a CIE-L*ab color to XYZ.
	*/
	List<int> labToXYZ(num l, num a, num b) {
	var y = (l + 16.0) / 116.0;
	var x = y + (a / 500.0);
	var z = y - (b / 200.0);
	if (Math.pow(x, 3) > 0.008856) {
	x = Math.pow(x, 3);
	} else {
	x = (x - 16.0 / 116) / 7.787;
	}
	if (Math.pow(y, 3) > 0.008856) {
	y = Math.pow(y, 3);
	} else {
	y = (y - 16.0 / 116.0) / 7.787;
	}
	if (Math.pow(z, 3) > 0.008856) {
	z = Math.pow(z, 3);
	} else {
	z = (z - 16.0 / 116.0) / 7.787;
	}

	return [(x * 95.047).toInt(), (y * 100.0).toInt(), (z * 108.883).toInt()];
	}

	/**
	* Convert an XYZ color to RGB.
	*/
	List<int> xyzToRGB(num x, num y, num z) {
	var b, g, r;
	x /= 100;
	y /= 100;
	z /= 100;
	r = (3.2406 * x) + (-1.5372 * y) + (-0.4986 * z);
	g = (-0.9689 * x) + (1.8758 * y) + (0.0415 * z);
	b = (0.0557 * x) + (-0.2040 * y) + (1.0570 * z);
	if (r > 0.0031308) {
	r = (1.055 * Math.pow(r, 0.4166666667)) - 0.055;
	} else {
	r *= 12.92;
	}
	if (g > 0.0031308) {
	g = (1.055 * Math.pow(g, 0.4166666667)) - 0.055;
	} else {
	g *= 12.92;
	}
	if (b > 0.0031308) {
	b = (1.055 * Math.pow(b, 0.4166666667)) - 0.055;
	} else {
	b *= 12.92;
	}

	return [(r * 255).toInt().clamp(0, 255),
	(g * 255).toInt().clamp(0, 255),
	(b * 255).toInt().clamp(0, 255)];
	}

	/**
	* Convert a CMYK color to RGB, where c, m, y, k values are in the range
	* [0, 255]. Returns a list [r, g, b] with values in the range [0, 255].
	*/
	List<int> cmykToRGB(num c, num m, num y, num k) {
	c /= 255.0;
	m /= 255.0;
	y /= 255.0;
	k /= 255.0;
	return [(255.0 * (1.0 - c) * (1.0 - k)).round(),
	(255.0 * (1.0 - m) * (1.0 - k)).round(),
	(255.0 * (1.0 - y) * (1.0 - k)).round()];
	}

	/**
	* Convert a CIE-L*ab color to RGB.
	*/
	List<int> labToRGB(num l, num a, num b) {
	const double ref_x = 95.047;
	const double ref_y = 100.000;
	const double ref_z = 108.883;

	double y = (l + 16.0) / 116.0;
	double x = a / 500.0 + y;
	double z = y - b / 200.0;

	double y3 = Math.pow(y, 3);
	if (y3 > 0.008856) {
	y = y3;
	} else {
	y = (y - 16 / 116) / 7.787;
	}

	double x3 = Math.pow(x, 3);
	if (x3 > 0.008856) {
	x = x3;
	} else {
	x = (x - 16 / 116) / 7.787;
	}

	double z3 = Math.pow(z, 3);
	if (z3 > 0.008856) {
	z = z3;
	} else {
	z = (z - 16 / 116) / 7.787;
	}

	x *= ref_x;
	y *= ref_y;
	z *= ref_z;

	x /= 100.0;
	y /= 100.0;
	z /= 100.0;

	// xyz to rgb
	double R = x * 3.2406 + y * (-1.5372) + z * (-0.4986);
	double G = x * (-0.9689) + y * 1.8758 + z * 0.0415;
	double B = x * 0.0557 + y * (-0.2040) + z * 1.0570;

	if (R > 0.0031308) {
	R = 1.055 * (Math.pow(R, 1.0 / 2.4)) - 0.055;
	} else {
	R = 12.92 * R;
	}

	if (G > 0.0031308) {
	G = 1.055 * (Math.pow(G, 1.0 / 2.4)) - 0.055;
	} else {
	G = 12.92 * G;
	}

	if (B > 0.0031308) {
	B = 1.055 * (Math.pow(B, 1.0 / 2.4)) - 0.055;
	} else {
	B = 12.92 * B;
	}

	return [(R * 255.0).toInt().clamp(0, 255),
	(G * 255.0).toInt().clamp(0, 255),
	(B * 255.0).toInt().clamp(0, 255)];
	}