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Toshihiro Shimizu |
890ddd |
#include "igs_color_rgb_hls.h"
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Shinya Kitaoka |
120a6e |
void igs::color::rgb_to_hls(const double red, // 0.0...1.0
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Shinya Kitaoka |
120a6e |
const double gre, // 0.0...1.0
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Shinya Kitaoka |
120a6e |
const double blu, // 0.0...1.0
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Shinya Kitaoka |
120a6e |
double &hue, /* 0.0...360.0 hue(色相) */
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Shinya Kitaoka |
120a6e |
double &lig, /* 0.0...1.0 lightness(明度) */
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Shinya Kitaoka |
120a6e |
double &sat /* 0.0...1.0 saturation(彩度) */
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Shinya Kitaoka |
120a6e |
) {
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Shinya Kitaoka |
120a6e |
const double maxi =
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Shinya Kitaoka |
120a6e |
(red < gre) ? ((gre < blu) ? blu : gre) : ((red < blu) ? blu : red);
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Shinya Kitaoka |
120a6e |
const double mini =
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Shinya Kitaoka |
120a6e |
(gre < red) ? ((blu < gre) ? blu : gre) : ((blu < red) ? blu : red);
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Toshihiro Shimizu |
890ddd |
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Shinya Kitaoka |
120a6e |
lig = (maxi + mini) / 2.0;
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Toshihiro Shimizu |
890ddd |
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Shinya Kitaoka |
120a6e |
if (maxi == mini) { /* RGB各値に差がない(=白黒で色がない) */
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Shinya Kitaoka |
120a6e |
sat = 0.0; /* saturation(彩度)はゼロ */
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Shinya Kitaoka |
120a6e |
hue = 0.0; /* hue(色相)は意味を持たない */
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Shinya Kitaoka |
120a6e |
} else { /* 色のあるとき */
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Shinya Kitaoka |
120a6e |
if (lig <= 0.5) {
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Shinya Kitaoka |
120a6e |
sat = (maxi - mini) / (maxi + mini);
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Shinya Kitaoka |
120a6e |
} else {
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Shinya Kitaoka |
120a6e |
sat = (maxi - mini) / (2.0 - (maxi + mini));
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Shinya Kitaoka |
120a6e |
}
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Toshihiro Shimizu |
890ddd |
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Shinya Kitaoka |
120a6e |
/* 色相(Hue) */
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Shinya Kitaoka |
120a6e |
const double rmid = (maxi - red) / (maxi - mini);
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Shinya Kitaoka |
120a6e |
const double gmid = (maxi - gre) / (maxi - mini);
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Shinya Kitaoka |
120a6e |
const double bmid = (maxi - blu) / (maxi - mini);
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Toshihiro Shimizu |
890ddd |
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Shinya Kitaoka |
120a6e |
/* -1 .. 1 マゼンタ(M)から黄色(Y)までの間の色 */
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Shinya Kitaoka |
120a6e |
if (red == maxi) {
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Shinya Kitaoka |
120a6e |
hue = bmid - gmid;
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Shinya Kitaoka |
120a6e |
}
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Toshihiro Shimizu |
890ddd |
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Shinya Kitaoka |
120a6e |
/* 1 .. 3 黄色(Y)からシアン(C)までの間の色 */
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Shinya Kitaoka |
120a6e |
else if (gre == maxi) {
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Shinya Kitaoka |
120a6e |
hue = 2.0 + rmid - bmid;
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Shinya Kitaoka |
120a6e |
}
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Toshihiro Shimizu |
890ddd |
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Shinya Kitaoka |
120a6e |
/* 3 .. 5 シアン(C)からマゼンタ(M)までの間の色 */
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Shinya Kitaoka |
120a6e |
else if (blu == maxi) {
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Shinya Kitaoka |
120a6e |
hue = 4.0 + gmid - rmid;
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Shinya Kitaoka |
120a6e |
}
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Shinya Kitaoka |
120a6e |
/*
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Shinya Kitaoka |
120a6e |
M-R-Y-G-C-B-M
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Shinya Kitaoka |
120a6e |
-1 0 1 2 3 4 5
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Shinya Kitaoka |
120a6e |
*/
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Shinya Kitaoka |
120a6e |
hue *= 60.0; /* -60 ... 300 */
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Shinya Kitaoka |
120a6e |
if (hue < 0.0) {
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Shinya Kitaoka |
120a6e |
hue += 360.0;
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Shinya Kitaoka |
120a6e |
}
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Shinya Kitaoka |
120a6e |
}
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Toshihiro Shimizu |
890ddd |
}
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Shinya Kitaoka |
120a6e |
namespace {
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Shinya Kitaoka |
120a6e |
double hls2rgb_calc(const double m1, const double m2, const double hue) {
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Shinya Kitaoka |
120a6e |
double hh = hue;
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Shinya Kitaoka |
120a6e |
while (360.0 < hh) {
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Shinya Kitaoka |
120a6e |
hh -= 360;
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Shinya Kitaoka |
120a6e |
}
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Shinya Kitaoka |
120a6e |
while (hh < 0.0) {
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Shinya Kitaoka |
120a6e |
hh += 360;
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Shinya Kitaoka |
120a6e |
}
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Shinya Kitaoka |
120a6e |
if (hh < 60.0) {
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Shinya Kitaoka |
120a6e |
return m1 + (m2 - m1) * hh / 60.0;
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Shinya Kitaoka |
120a6e |
} else if (hh < 180.0) {
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Shinya Kitaoka |
120a6e |
return m2;
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Shinya Kitaoka |
120a6e |
} else if (hh < 240.0) {
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Shinya Kitaoka |
120a6e |
return m1 + (m2 - m1) * (240.0 - hh) / 60.0;
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Shinya Kitaoka |
120a6e |
}
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Shinya Kitaoka |
120a6e |
return m1; /* 240 ... 360 */
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Toshihiro Shimizu |
890ddd |
}
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Toshihiro Shimizu |
890ddd |
}
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Toshihiro Shimizu |
890ddd |
void igs::color::hls_to_rgb(
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Shinya Kitaoka |
120a6e |
const double hue, /* 0.0...360.0 hue(色相) */
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Shinya Kitaoka |
120a6e |
const double lig, /* 0.0...1.0 lightness(明度) */
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Shinya Kitaoka |
120a6e |
const double sat, /* 0.0...1.0 saturation(彩度) */
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Shinya Kitaoka |
120a6e |
double &red, /* 0.0...1.0 */
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Shinya Kitaoka |
120a6e |
double &gre, /* 0.0...1.0 */
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Shinya Kitaoka |
120a6e |
double &blu /* 0.0...1.0 */
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Shinya Kitaoka |
120a6e |
) {
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Shinya Kitaoka |
120a6e |
if (0.0 == sat) { /* 白黒で色がない */
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Shinya Kitaoka |
120a6e |
red = gre = blu = lig;
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Shinya Kitaoka |
120a6e |
} else { /* 色のあるとき */
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Shinya Kitaoka |
120a6e |
const double m2 =
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Shinya Kitaoka |
120a6e |
(lig <= 0.5) ? (lig * (1.0 + sat)) : (lig + sat - lig * sat);
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Shinya Kitaoka |
120a6e |
const double m1 = 2.0 * lig - m2;
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Shinya Kitaoka |
120a6e |
red = hls2rgb_calc(m1, m2, hue + 120.0);
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Shinya Kitaoka |
120a6e |
gre = hls2rgb_calc(m1, m2, hue);
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Shinya Kitaoka |
120a6e |
blu = hls2rgb_calc(m1, m2, hue - 120.0);
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Shinya Kitaoka |
120a6e |
}
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Toshihiro Shimizu |
890ddd |
}
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