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128 lines
3.5 KiB
128 lines
3.5 KiB
/*
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* Copyright (c) 2010 Tim Baumann
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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// NOTE:
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// Extracted from ColorTriangle and
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// Converted to ES6 by MightyPork (2017)
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/*******************
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* Color conversion *
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*******************/
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const M = Math
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const PI = M.PI
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exports.hue_to_rgb = function (v1, v2, h) {
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if (h < 0) h += 1
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if (h > 1) h -= 1
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if ((6 * h) < 1) return v1 + (v2 - v1) * 6 * h
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if ((2 * h) < 1) return v2
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if ((3 * h) < 2) return v1 + (v2 - v1) * ((2 / 3) - h) * 6
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return v1
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}
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exports.hsl_to_rgb = function (h, s, l) {
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h /= 2 * PI
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let r, g, b
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if (s === 0) {
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r = g = b = l
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} else {
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let var_1, var_2
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if (l < 0.5) var_2 = l * (1 + s)
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else var_2 = (l + s) - (s * l)
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var_1 = 2 * l - var_2
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r = exports.hue_to_rgb(var_1, var_2, h + (1 / 3))
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g = exports.hue_to_rgb(var_1, var_2, h)
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b = exports.hue_to_rgb(var_1, var_2, h - (1 / 3))
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}
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return [r, g, b]
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}
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exports.rgb_to_hsl = function (r, g, b) {
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const min = M.min(r, g, b)
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const max = M.max(r, g, b)
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const d = max - min // delta
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let h, s, l
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l = (max + min) / 2
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if (d === 0) {
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// gray
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h = s = 0 // HSL results from 0 to 1
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} else {
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// chroma
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if (l < 0.5) s = d / (max + min)
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else s = d / (2 - max - min)
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const d_r = (((max - r) / 6) + (d / 2)) / d
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const d_g = (((max - g) / 6) + (d / 2)) / d
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const d_b = (((max - b) / 6) + (d / 2)) / d // deltas
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if (r === max) h = d_b - d_g
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else if (g === max) h = (1 / 3) + d_r - d_b
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else if (b === max) h = (2 / 3) + d_g - d_r
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if (h < 0) h += 1
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else if (h > 1) h -= 1
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}
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h *= 2 * PI
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return [h, s, l]
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}
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exports.hex_to_rgb = function (hex) {
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const groups = hex.match(/^#([A-Fa-f0-9]+)$/)
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if (groups && groups[1].length % 3 === 0) {
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hex = groups[1]
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const bytes = hex.length / 3
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const max = Math.pow(16, bytes) - 1
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const r = parseInt(hex.slice(0 * bytes, 1 * bytes), 16) / max
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const g = parseInt(hex.slice(1 * bytes, 2 * bytes), 16) / max
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const b = parseInt(hex.slice(2 * bytes, 3 * bytes), 16) / max
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return [r, g, b]
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}
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return [0, 0, 0]
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}
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function pad (n) {
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if (n.length === 1) n = '0' + n
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return n
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}
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exports.rgb255_to_hex = function (r, g, b) {
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r = r.toString(16)
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g = g.toString(16)
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b = b.toString(16)
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return `#${pad(r)}${pad(g)}${pad(b)}`
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}
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exports.rgb_to_hex = function (r, g, b) {
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r = Math.round(r * 255).toString(16)
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g = Math.round(g * 255).toString(16)
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b = Math.round(b * 255).toString(16)
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return `#${pad(r)}${pad(g)}${pad(b)}`
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}
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