Michaël Lemaire
0058a0a8e3
...to avoid otherwise unused HSL conversion, which causes problems for some RGB values (like Color(1, 0, 0))
89 lines
1.8 KiB
C++
89 lines
1.8 KiB
C++
#include "ColorHSL.h"
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#include "Color.h"
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static inline double _hue2rgb(double p, double q, double t)
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{
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if (t < 0.0) t += 1;
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if (t > 1.0) t -= 1;
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if (t < 1.0 / 6.0) return p + (q - p) * 6.0 * t;
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if (t < 1.0 / 2.0) return q;
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if (t < 2.0 / 3.0) return p + (q - p) * (2.0 / 3.0 - t) * 6.0;
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return p;
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}
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Color colorFromHSL(const ColorHSL &col)
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{
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Color result;
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if (col.s == 0)
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{
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result.r = result.g = result.b = col.l;
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}
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else
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{
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double q = col.l < 0.5 ? col.l * (1.0 + col.s) : col.l + col.s - col.l * col.s;
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double p = 2 * col.l - q;
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result.r = _hue2rgb(p, q, col.h + 1.0 / 3.0);
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result.g = _hue2rgb(p, q, col.h);
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result.b = _hue2rgb(p, q, col.h - 1.0 / 3.0);
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}
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result.a = col.a;
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return result;
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}
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ColorHSL colorToHSL(const Color &col)
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{
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ColorHSL result;
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double min, max;
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max = col.r > col.g ? col.r : col.g;
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max = col.b > max ? col.b : max;
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min = col.r < col.g ? col.r : col.g;
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min = col.b < min ? col.b : min;
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result.h = result.s = result.l = (max + min) / 2.0;
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if (max == min)
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{
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result.h = result.s = 0.0;
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}
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else
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{
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double d = max - min;
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result.s = result.l > 0.5 ? d / (2.0 - max - min) : d / (max + min);
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if (max == col.r)
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{
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result.h = (col.g - col.b) / d + (col.g < col.b ? 6.0 : 0);
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}
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else if (max == col.g)
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{
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result.h = (col.b - col.r) / d + 2.0;
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}
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else
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{
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result.h = (col.r - col.g) / d + 4.0;
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}
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result.h /= 6.0;
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}
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result.a = col.a;
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return result;
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}
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ColorHSL colorHSLFromValues(double h, double s, double l, double a)
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{
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ColorHSL result;
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result.h = h;
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result.s = s;
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result.l = l;
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result.a = a;
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return result;
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}
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