//-----------------------------------------------------------------------------
// LCH(uv) to RGB
void LCHUVtoRGB(float L, float C, float H, float* RGB)
{
LCHtoLAB(L,C,H,RGB);
LUVtoXYZ(RGB[0],RGB[1],RGB[2],RGB);
XYZtoRGB(RGB[0],RGB[1],RGB[2],RGB);
}
void convert(unsigned char *buf, int width, int height, int de) {
double angle_chroma[360];
double angle_hue[360];
double angle_hue2[360];
double minchroma = 999;
double maxchroma = 0;
{
int i;
for (i = 0; i < 360; i++) {
angle_chroma[i] = 9999;
}
double f;
for (f = 0; f < 360; f += .25) {
angle_hue[(int) ((angletohue(f) - angletohue(0)) / (angletohue(360) - angletohue(0)) * 360)] = f;
angle_hue2[(int) f] = ((angletohue(f) - angletohue(0)) / (angletohue(360) - angletohue(0)) * 360);
}
double a;
for (a = -80; a <= 80; a += .1) {
int dir;
for (dir = -1; dir <= 1; dir += 2) {
double b = dir * 335.582 * exp(- a * a / (2 * 15.5723 * 15.5723)) / (15.5723 * sqrt(2 * M_PI));
double h = atan2(b, a);
double c = sqrt(a * a + b * b);
h -= 0.075;
if (h < 0) {
h += 2 * M_PI;
}
h = floor(h * 180 / M_PI);
if (c < angle_chroma[(int) h]) {
angle_chroma[(int) h] = c;
}
}
}
for (i = 0; i < 360; i++) {
if (angle_chroma[i] < minchroma) {
minchroma = angle_chroma[i];
}
if (angle_chroma[i] > maxchroma) {
maxchroma = angle_chroma[i];
}
}
}
int *buf2 = malloc(width * height * 4 * sizeof(int));
int x, y;
for (y = 0; y < height; y++) {
for (x = 0; x < width; x++) {
int r = buf[(y * width + x) * 4 + 0];
int g = buf[(y * width + x) * 4 + 1];
int b = buf[(y * width + x) * 4 + 2];
double X, Y, Z;
double L, A, B;
double C, H;
RGBtoXYZ(r, g, b, &X, &Y, &Z);
XYZtoLAB(X, Y, Z, &L, &A, &B);
LABtoLCH(L, A, B, &L, &C, &H);
if (H < 0) {
H += 2 * M_PI;
}
if (de) {
// desaturate
C = C * minchroma / angle_chroma[(int) (H * 180 / M_PI)];
// shift hue
int hh = (int) (H * 180 / M_PI + 720) % 360;
H = angle_hue2[hh] * M_PI / 180;
} else {
// shift hue
int hh = (int) (H * 180 / M_PI + 720) % 360;
H = angle_hue[hh] * M_PI / 180;
// resaturate
C = C / minchroma * angle_chroma[(int) (H * 180 / M_PI)];
C *= minchroma / maxchroma;
}
LCHtoLAB(L, C, H, &L, &A, &B);
LABtoXYZ(L, A, B, &X, &Y, &Z);
XYZtoRGB(X, Y, Z, &r, &g, &b);
buf2[(y * width + x) * 4 + 0] = r;
buf2[(y * width + x) * 4 + 1] = g;
buf2[(y * width + x) * 4 + 2] = b;
}
}
int max = 0;
for (x = 0; x < width * height; x++) {
int i;
for (i = 0; i < 3; i++) {
if (buf2[x * 4 + i] > max) {
max = buf2[x * 4 + i];
}
}
}
for (x = 0; x < width * height; x++) {
int i;
for (i = 0; i < 3; i++) {
buf[x * 4 + i] = buf2[x * 4 + i] * 255 / max;
if (buf2[x * 4 + i] < 0) {
buf[x * 4 + i] = 0;
}
}
}
}
