cmyk.js

/**
 * @module color-space/cmyk
 */
import rgb from './rgb.js';

/** @type {Partial<import('./index.js').ColorSpace>} */
const cmyk = {
	name: 'cmyk',
	min: [0,0,0,0],
	max: [100,100,100,100],
	channel: ['cyan', 'magenta', 'yellow', 'black'],
	alias: ['CMYK'],

	rgb: function(cmyk) {
		var c = cmyk[0] / 100,
				m = cmyk[1] / 100,
				y = cmyk[2] / 100,
				k = cmyk[3] / 100,
				r, g, b;

		r = 1 - Math.min(1, c * (1 - k) + k);
		g = 1 - Math.min(1, m * (1 - k) + k);
		b = 1 - Math.min(1, y * (1 - k) + k);
		return [r * 255, g * 255, b * 255];
	}
};


//extend rgb
rgb.cmyk = function(rgb) {
	var r = rgb[0] / 255,
			g = rgb[1] / 255,
			b = rgb[2] / 255,
			c, m, y, k;

	k = Math.min(1 - r, 1 - g, 1 - b);
	c = (1 - r - k) / (1 - k) || 0;
	m = (1 - g - k) / (1 - k) || 0;
	y = (1 - b - k) / (1 - k) || 0;
	return [c * 100, m * 100, y * 100, k * 100];
};

export default /** @type {import('./index.js').ColorSpace} */ (cmyk);