Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

113 lines (89 sloc) 2.251 kb
#include "imager.h"
#include <math.h>
static double
gauss(int x, double std) {
return 1.0/(sqrt(2.0*PI)*std)*exp(-(double)(x)*(double)(x)/(2*std*std));
}
/* Counters are as follows
l: lines
i: columns
c: filter coeffs
ch: channels
pc: coeff equalization
*/
int
i_gaussian(i_img *im, double stddev) {
int i, c, ch;
i_img_dim x, y;
double pc;
double *coeff;
double res[MAXCHANNELS];
i_img *timg;
int radius, diameter;
mm_log((1,"i_gaussian(im %p, stdev %.2f)\n",im,stddev));
i_clear_error();
if (stddev <= 0) {
i_push_error(0, "stddev must be positive");
return 0;
}
/* totally silly cutoff */
if (stddev > 1000) {
stddev = 1000;
}
timg = i_sametype(im, im->xsize, im->ysize);
if (im->bits <= 8)
radius = ceil(2 * stddev);
else
radius = ceil(3 * stddev);
diameter = 1 + radius * 2;
coeff = mymalloc(sizeof(double) * diameter);
for(i=0;i <= radius;i++)
coeff[radius + i]=coeff[radius - i]=gauss(i, stddev);
pc=0;
for(i=0; i < diameter; i++)
pc+=coeff[i];
for(i=0;i < diameter;i++)
coeff[i] /= pc;
#code im->bits <= 8
IM_COLOR rcolor;
for(y = 0; y < im->ysize; y++) {
for(x = 0; x < im->xsize; x++) {
pc=0.0;
for(ch=0;ch<im->channels;ch++)
res[ch]=0;
for(c = 0;c < diameter; c++)
if (IM_GPIX(im,x+c-radius,y,&rcolor)!=-1) {
for(ch=0;ch<im->channels;ch++)
res[ch]+= rcolor.channel[ch] * coeff[c];
pc+=coeff[c];
}
for(ch=0;ch<im->channels;ch++) {
double value = res[ch] / pc;
rcolor.channel[ch] = value > IM_SAMPLE_MAX ? IM_SAMPLE_MAX : IM_ROUND(value);
}
IM_PPIX(timg, x, y, &rcolor);
}
}
for(x = 0;x < im->xsize; x++) {
for(y = 0; y < im->ysize; y++) {
pc=0.0;
for(ch=0; ch<im->channels; ch++)
res[ch]=0;
for(c=0; c < diameter; c++)
if (IM_GPIX(timg, x, y+c-radius, &rcolor)!=-1) {
for(ch=0;ch<im->channels;ch++)
res[ch]+= rcolor.channel[ch] * coeff[c];
pc+=coeff[c];
}
for(ch=0;ch<im->channels;ch++) {
double value = res[ch]/pc;
rcolor.channel[ch] = value > IM_SAMPLE_MAX ? IM_SAMPLE_MAX : IM_ROUND(value);
}
IM_PPIX(im, x, y, &rcolor);
}
}
#/code
myfree(coeff);
i_img_destroy(timg);
return 1;
}
Jump to Line
Something went wrong with that request. Please try again.