// Copyright (C) 2013 Massachusetts Institute of Technology // // This program is free software; you can redistribute it and/or // modify it under the terms of the GNU General Public License version 2, // as published by the Free Software Foundation. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // // You should have received a copy of the GNU General Public License // along with this program; if not, write to the Free Software // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. // Scratch HTML5 Player // Color.js // Based on the original by John Maloney Color = function() {}; Color.fromHSV = function(h, s, v) { var r, g, b; h = h % 360; if (h < 0) h += 360; s = Math.max(0, Math.min(s, 1)); v = Math.max(0, Math.min(v, 1)); var i = Math.floor(h / 60); var f = (h / 60) - i; var p = v * (1 - s); var q = v * (1 - s * f); var t = v * (1 - s * (1 - f)); if (i == 0) { r = v; g = t; b = p; } else if (i == 1) { r = q; g = v; b = p; } else if (i == 2) { r = p; g = v; b = t; } else if (i == 3) { r = p; g = q; b = v; } else if (i == 4) { r = t; g = p; b = v; } else if (i == 5) { r = v; g = p; b = q; } r = Math.floor(r * 255); g = Math.floor(g * 255); b = Math.floor(b * 255); return (r << 16) | (g << 8) | b; }; Color.rgb2hsv = function(rgb) { var h, s, v, x, f, i; var r = ((rgb >> 16) & 255) / 255; var g = ((rgb >> 8) & 255) / 255; var b = (rgb & 255) / 255; x = Math.min(Math.min(r, g), b); v = Math.max(Math.max(r, g), b); if (x == v) return [0, 0, v]; // gray; hue arbitrarily reported as zero f = r == x ? g - b : g == x ? b - r : r - g; i = r == x ? 3 : g == x ? 5 : 1; h = ((i - f / (v - x)) * 60) % 360; s = (v - x) / v; return [h, s, v]; }; Color.scaleBrightness = function(rgb, scale) { var hsv = Color.rgb2hsv(rgb); scale = Math.max(0, Math.min(scale, 1)); return Color.fromHSV(hsv[0], hsv[1], scale * hsv[2]); }; Color.mixRGB = function(rgb1, rgb2, fraction) { // Mix rgb1 with rgb2. 0 gives all rgb1, 1 gives rbg2, .5 mixes them 50/50. if (fraction <= 0) return rgb1; if (fraction >= 1) return rgb2; var r1 = (rgb1 >> 16) & 255; var g1 = (rgb1 >> 8) & 255; var b1 = rgb1 & 255 var r2 = (rgb2 >> 16) & 255; var g2 = (rgb2 >> 8) & 255; var b2 = rgb2 & 255 var r = ((fraction * r2) + ((1.0 - fraction) * r1)) & 255; var g = ((fraction * g2) + ((1.0 - fraction) * g1)) & 255; var b = ((fraction * b2) + ((1.0 - fraction) * b1)) & 255; return (r << 16) | (g << 8) | b; }; Color.random = function() { // return a random color var h = 360 * Math.random(); var s = 0.7 + (0.3 * Math.random()); var v = 0.6 + (0.4 * Math.random()); return Color.fromHSV(h, s, v); };