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#include <string.h>
#include "global_variables.h"
#include "dng.h"
void
dng_coeff (double cc[4][4], double cm[4][3], double xyz[3])
{
static const double rgb_xyz[3][3] = { /* RGB from XYZ */
{ 3.240479, -1.537150, -0.498535 },
{ -0.969256, 1.875992, 0.041556 },
{ 0.055648, -0.204043, 1.057311 } };
#if 0
static const double xyz_rgb[3][3] = { /* XYZ from RGB */
{ 0.412453, 0.357580, 0.180423 },
{ 0.212671, 0.715160, 0.072169 },
{ 0.019334, 0.119193, 0.950227 } };
#endif
double cam_xyz[4][3], xyz_cam[3][4], invert[3][6], num;
int i, j, k;
memset (cam_xyz, 0, sizeof cam_xyz);
for (i=0; i < colors; i++)
for (j=0; j < 3; j++)
for (k=0; k < colors; k++)
cam_xyz[i][j] += cc[i][k] * cm[k][j] * xyz[j];
for (i=0; i < colors; i++) {
for (num=j=0; j < 3; j++)
num += cam_xyz[i][j];
for (j=0; j < 3; j++)
cam_xyz[i][j] /= num;
pre_mul[i] = 1 / num;
}
for (i=0; i < 3; i++) {
for (j=0; j < 6; j++)
invert[i][j] = j == i+3;
for (j=0; j < 3; j++)
for (k=0; k < colors; k++)
invert[i][j] += cam_xyz[k][i] * cam_xyz[k][j];
}
for (i=0; i < 3; i++) {
num = invert[i][i];
for (j=0; j < 6; j++) /* Normalize row i */
invert[i][j] /= num;
for (k=0; k < 3; k++) { /* Subtract it from other rows */
if (k==i) continue;
num = invert[k][i];
for (j=0; j < 6; j++)
invert[k][j] -= invert[i][j] * num;
}
}
memset (xyz_cam, 0, sizeof xyz_cam);
for (i=0; i < 3; i++)
for (j=0; j < colors; j++)
for (k=0; k < 3; k++)
xyz_cam[i][j] += invert[i][k+3] * cam_xyz[j][k];
memset (coeff, 0, sizeof coeff);
for (i=0; i < 3; i++)
for (j=0; j < colors; j++)
for (k=0; k < 3; k++)
coeff[i][j] += rgb_xyz[i][k] * xyz_cam[k][j];
for (num=j=0; j < colors; j++)
num += coeff[1][j];
for (i=0; i < 3; i++) {
for (j=0; j < colors; j++)
coeff[i][j] /= num;
}
use_coeff = 1;
}
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