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Initial implementation of lanczos resize algo

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This commit is contained in:
Ilia Popov
2010-10-27 01:42:42 +02:00
parent f0661fe294
commit 484c5d94a1
2 changed files with 107 additions and 1 deletions
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2
rtengine/curves.cc
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@@ -694,7 +694,7 @@ void CurveFactory::complexCurve (double ecomp, double black, double hlcompr, dou
double def_mul = pow (2.0, defmul);
printf ("def_mul= %f ecomp= %f black= %f hlcompr= %f shcompr= %f br= %f contr= %f defmul= %f gamma= %f, skip= %d \n",def_mul,ecomp,black,hlcompr,shcompr,br,contr,defmul,gamma_,skip);
//printf ("def_mul= %f ecomp= %f black= %f hlcompr= %f shcompr= %f br= %f contr= %f defmul= %f gamma= %f, skip= %d \n",def_mul,ecomp,black,hlcompr,shcompr,br,contr,defmul,gamma_,skip);
// compute parameters of the gamma curve
double start = exp(gamma_*log( -0.099 / ((1.0/gamma_-1.0)*1.099 )));

106
rtengine/ipresize.cc
View File

@@ -23,6 +23,8 @@
#include <omp.h>
#endif
#include <iostream>
namespace rtengine {
#undef CLIP
@@ -35,6 +37,110 @@ namespace rtengine {
void ImProcFunctions::resize (Image16* src, Image16* dst) {
if(true) {
//if(params->resize.method == "Lanczos") {
double delta = 1.0 / params->resize.scale;
const double a = 3.0;
const int support = 6;
const int kc = 2;
Image16 * tmp = new Image16(src->width, dst->height);
for (int i = 0; i < tmp->height; i++) {
// y coord of the center of pixel on src image
double y0 = (i + 0.5) * delta - 0.5;
int i0 = floor(y0);
// weights for interpolation in y direction
double w[support];
// sum of weights used for normalization
double ww = 0.0;
int ii0 = std::max(0, i0 - kc);
int ii1 = std::min(src->height, i0 - kc + support);
// calculate weights
for (int ii = ii0; ii < ii1; ii++) {
int k = ii - i0 + kc;
double z = M_PI * (y0 - (i0 + k - kc));
w[k] = sin(z) * sin(a*z) / (a * z * z);
ww += w[k];
}
// normalize weights
for (int k = 0; k < support; k++) {
w[k] /= ww;
}
for (int j = 0; j < tmp->width; j++) {
double r = 0.0, g = 0.0, b = 0.0;
for (int ii = ii0; ii < ii1; ii++) {
int k = ii - i0 + kc;
r += w[k] * src->r[ii][j];
g += w[k] * src->g[ii][j];
b += w[k] * src->b[ii][j];
}
tmp->r[i][j] = CLIP((int)r);
tmp->g[i][j] = CLIP((int)g);
tmp->b[i][j] = CLIP((int)b);
}
}
for (int j = 0; j < dst->width; j++) {
// y coord of the center of pixel on src image
double x0 = (j + 0.5) * delta - 0.5;
int j0 = floor(x0);
// weights for interpolation in y direction
double w[support];
// sum of weights used for normalization
double ww = 0.0;
int jj0 = std::max(0, j0 - kc);
int jj1 = std::min(tmp->width, j0 - kc + support);
// calculate weights
for (int jj = jj0; jj < jj1; jj++) {
int k = jj - j0 + kc;
double z = M_PI * (x0 - (j0 + k - kc));
w[k] = sin(z) * sin(a*z) / (a * z * z);
ww += w[k];
}
// normalize weights
for (int k = 0; k < support; k++) {
w[k] /= ww;
}
for (int i = 0; i < dst->height; i++) {
double r = 0.0, g = 0.0, b = 0.0;
for (int jj = jj0; jj < jj1; jj++) {
int k = jj - j0 + kc;
r += w[k] * tmp->r[i][jj];
g += w[k] * tmp->g[i][jj];
b += w[k] * tmp->b[i][jj];
}
dst->r[i][j] = CLIP((int)r);
dst->g[i][j] = CLIP((int)g);
dst->b[i][j] = CLIP((int)b);
}
}
delete tmp;
}
return;
if(params->resize.method == "Downscale (Better)") {
// small-scale algorithm by Ilia
// provides much better quality on small scales