mirror of
https://github.com/scratchfoundation/scratch-html5.git
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89 lines
3 KiB
JavaScript
89 lines
3 KiB
JavaScript
// Copyright (C) 2013 Massachusetts Institute of Technology
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License version 2,
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// as published by the Free Software Foundation.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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// Scratch HTML5 Player
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// Color.js
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// Based on the original by John Maloney
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Color = function() {};
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Color.fromHSV = function(h, s, v) {
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var r, g, b;
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h = h % 360;
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if (h < 0) h += 360;
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s = Math.max(0, Math.min(s, 1));
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v = Math.max(0, Math.min(v, 1));
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var i = Math.floor(h / 60);
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var f = (h / 60) - i;
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var p = v * (1 - s);
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var q = v * (1 - s * f);
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var t = v * (1 - s * (1 - f));
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if (i == 0) { r = v; g = t; b = p; }
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else if (i == 1) { r = q; g = v; b = p; }
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else if (i == 2) { r = p; g = v; b = t; }
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else if (i == 3) { r = p; g = q; b = v; }
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else if (i == 4) { r = t; g = p; b = v; }
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else if (i == 5) { r = v; g = p; b = q; }
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r = Math.floor(r * 255);
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g = Math.floor(g * 255);
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b = Math.floor(b * 255);
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return (r << 16) | (g << 8) | b;
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};
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Color.rgb2hsv = function(rgb) {
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var h, s, v, x, f, i;
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var r = ((rgb >> 16) & 255) / 255;
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var g = ((rgb >> 8) & 255) / 255;
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var b = (rgb & 255) / 255;
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x = Math.min(Math.min(r, g), b);
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v = Math.max(Math.max(r, g), b);
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if (x == v) return [0, 0, v]; // gray; hue arbitrarily reported as zero
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f = r == x ? g - b : g == x ? b - r : r - g;
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i = r == x ? 3 : g == x ? 5 : 1;
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h = ((i - f / (v - x)) * 60) % 360;
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s = (v - x) / v;
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return [h, s, v];
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};
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Color.scaleBrightness = function(rgb, scale) {
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var hsv = Color.rgb2hsv(rgb);
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scale = Math.max(0, Math.min(scale, 1));
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return Color.fromHSV(hsv[0], hsv[1], scale * hsv[2]);
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};
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Color.mixRGB = function(rgb1, rgb2, fraction) {
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// Mix rgb1 with rgb2. 0 gives all rgb1, 1 gives rbg2, .5 mixes them 50/50.
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if (fraction <= 0) return rgb1;
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if (fraction >= 1) return rgb2;
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var r1 = (rgb1 >> 16) & 255;
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var g1 = (rgb1 >> 8) & 255;
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var b1 = rgb1 & 255
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var r2 = (rgb2 >> 16) & 255;
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var g2 = (rgb2 >> 8) & 255;
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var b2 = rgb2 & 255
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var r = ((fraction * r2) + ((1.0 - fraction) * r1)) & 255;
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var g = ((fraction * g2) + ((1.0 - fraction) * g1)) & 255;
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var b = ((fraction * b2) + ((1.0 - fraction) * b1)) & 255;
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return (r << 16) | (g << 8) | b;
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};
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Color.random = function() {
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// return a random color
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var h = 360 * Math.random();
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var s = 0.7 + (0.3 * Math.random());
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var v = 0.6 + (0.4 * Math.random());
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return Color.fromHSV(h, s, v);
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};
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