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RGB to HSL and HSL to RGB conversion functions
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| /* | |
| * Copyright 2011 Maciej Ciemborowicz | |
| * https://maciej-ciemborowicz.eu | |
| * | |
| * Licensed under the Apache License, Version 2.0 (the "License"); | |
| * you may not use this file except in compliance with the License. | |
| * You may obtain a copy of the License at | |
| * | |
| * http://www.apache.org/licenses/LICENSE-2.0 | |
| * | |
| * Unless required by applicable law or agreed to in writing, software | |
| * distributed under the License is distributed on an "AS IS" BASIS, | |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| * See the License for the specific language governing permissions and | |
| * limitations under the License. | |
| */ | |
| #define MIN(a,b) ((a)<(b)?(a):(b)) | |
| #define MAX(a,b) ((a)>(b)?(a):(b)) | |
| typedef struct rgb { | |
| float r, g, b; | |
| } RGB; | |
| typedef struct hsl { | |
| float h, s, l; | |
| } HSL; | |
| /* | |
| * Converts an RGB color value to HSL. Conversion formula | |
| * adapted from http://en.wikipedia.org/wiki/HSL_color_space. | |
| * Assumes r, g, and b are contained in the set [0, 255] and | |
| * returns HSL in the set [0, 1]. | |
| */ | |
| HSL rgb2hsl(float r, float g, float b) { | |
| HSL result; | |
| r /= 255; | |
| g /= 255; | |
| b /= 255; | |
| float max = MAX(MAX(r,g),b); | |
| float min = MIN(MIN(r,g),b); | |
| result.h = result.s = result.l = (max + min) / 2; | |
| if (max == min) { | |
| result.h = result.s = 0; // achromatic | |
| } | |
| else { | |
| float d = max - min; | |
| result.s = (result.l > 0.5) ? d / (2 - max - min) : d / (max + min); | |
| if (max == r) { | |
| result.h = (g - b) / d + (g < b ? 6 : 0); | |
| } | |
| else if (max == g) { | |
| result.h = (b - r) / d + 2; | |
| } | |
| else if (max == b) { | |
| result.h = (r - g) / d + 4; | |
| } | |
| result.h /= 6; | |
| } | |
| return result; | |
| } | |
| //////////////////////////////////////////////////////////////////////// | |
| /* | |
| * Converts an HUE to r, g or b. | |
| * returns float in the set [0, 1]. | |
| */ | |
| float hue2rgb(float p, float q, float t) { | |
| if (t < 0) | |
| t += 1; | |
| if (t > 1) | |
| t -= 1; | |
| if (t < 1./6) | |
| return p + (q - p) * 6 * t; | |
| if (t < 1./2) | |
| return q; | |
| if (t < 2./3) | |
| return p + (q - p) * (2./3 - t) * 6; | |
| return p; | |
| } | |
| //////////////////////////////////////////////////////////////////////// | |
| /* | |
| * Converts an HSL color value to RGB. Conversion formula | |
| * adapted from http://en.wikipedia.org/wiki/HSL_color_space. | |
| * Assumes h, s, and l are contained in the set [0, 1] and | |
| * returns RGB in the set [0, 255]. | |
| */ | |
| RGB hsl2rgb(float h, float s, float l) { | |
| RGB result; | |
| if(0 == s) { | |
| result.r = result.g = result.b = l * 255; // achromatic | |
| } | |
| else { | |
| float q = l < 0.5 ? l * (1 + s) : l + s - l * s; | |
| float p = 2 * l - q; | |
| result.r = hue2rgb(p, q, h + 1./3) * 255; | |
| result.g = hue2rgb(p, q, h) * 255; | |
| result.b = hue2rgb(p, q, h - 1./3) * 255; | |
| } | |
| return result; | |
| } |
Author
@alpheratz0 fixed 😂. Since this code has become so popular, I see no other choice but to maintain it 😂.
lets go!
I also added the Apache license comment at the beginning, that says what I said before.
noooo RIP "do what you want" license
I searched rgb to hsl cpp in google, and this gist was the first result. The search engines have seen you, @ciembor, and they bestow their blessings upon you.
I searched
rgb to hsl cppin google, and this gist was the first result. The search engines have seen you, @ciembor, and they bestow their blessings upon you.
i remember searching it up too!
looks kinda messy ngl
if it ain't broke, don't fix it I'M SORRY
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@sixtyfourLEC I'm glad you still use search engines instead of LLM, because I can learn something. But you must tell me what is messy 😂.