[6a3a178] | 1 | import { rgb2value, rgb2whiteness, rgb2hue } from './util';
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| 2 |
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| 3 | /* Convert between RGB and HSV
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| 4 | /* ========================================================================== */
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| 5 |
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| 6 | export function rgb2hsv(rgbR, rgbG, rgbB, fallbackhue) {
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| 7 | const hsvV = rgb2value(rgbR, rgbG, rgbB);
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| 8 | const hsvW = rgb2whiteness(rgbR, rgbG, rgbB);
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| 9 | const hsvH = rgb2hue(rgbR, rgbG, rgbB, fallbackhue);
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| 10 |
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| 11 | // calculate saturation
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| 12 | const hsvS = hsvV === hsvW ? 0 : (hsvV - hsvW) / hsvV * 100;
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| 13 |
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| 14 | return [ hsvH, hsvS, hsvV ];
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| 15 | }
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| 16 |
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| 17 | export function hsv2rgb(hsvH, hsvS, hsvV) {
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| 18 | const rgbI = Math.floor(hsvH / 60);
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| 19 |
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| 20 | // calculate rgb parts
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| 21 | const rgbF = hsvH / 60 - rgbI & 1 ? hsvH / 60 - rgbI : 1 - hsvH / 60 - rgbI;
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| 22 | const rgbM = hsvV * (100 - hsvS) / 100;
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| 23 | const rgbN = hsvV * (100 - hsvS * rgbF) / 100;
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| 24 |
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| 25 | const [ rgbR, rgbG, rgbB ] = rgbI === 5
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| 26 | ? [ hsvV, rgbM, rgbN ]
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| 27 | : rgbI === 4
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| 28 | ? [ rgbN, rgbM, hsvV ]
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| 29 | : rgbI === 3
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| 30 | ? [ rgbM, rgbN, hsvV ]
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| 31 | : rgbI === 2
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| 32 | ? [ rgbM, hsvV, rgbN ]
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| 33 | : rgbI === 1
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| 34 | ? [ rgbN, hsvV, rgbM ]
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| 35 | : [ hsvV, rgbN, rgbM ];
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| 36 |
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| 37 | return [ rgbR, rgbG, rgbB ];
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| 38 | }
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| 39 |
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| 40 | /*
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| 41 |
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| 42 | References
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| 43 | ----------
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| 44 |
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| 45 | - http://alvyray.com/Papers/CG/hsv2rgb.htm
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| 46 |
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| 47 | /* ========================================================================== */
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