#include "imager.h"

/*
  General convolution for 2d decoupled filters
  end effects are acounted for by increasing
  scaling the result with the sum of used coefficients

  coeff: (float array) coefficients for filter
    len: length of filter.. number of coefficients
           note that this has to be an odd number
           (since the filter is even);
*/

void
i_conv(i_img *im,const float *coeff,int len) {
  int i,l,c,ch,center;
  double pc;
  double res[11];
  i_img *timg;

  mm_log((1,"i_conv(im %p, coeff %p, len %d)\n",im,coeff,len));
 
  timg = i_sametype(im, im->xsize, im->ysize);

  center=(len-1)/2;

#code im->bits <= 8
  IM_COLOR rcolor;
  /* don't move the calculation of pc up here, it depends on which pixels
     are readable */
  for(l=0;l<im->ysize;l++) {
    for(i=0;i<im->xsize;i++) {
      pc=0.0;
      for(ch=0;ch<im->channels;ch++) 
	res[ch]=0;
      for(c=0;c<len;c++)
	if (IM_GPIX(im,i+c-center,l,&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 temp = res[ch]/pc;
        rcolor.channel[ch] = 
          temp < 0 ? 0 : temp > IM_SAMPLE_MAX ? IM_SAMPLE_MAX : (IM_SAMPLE_T)temp;
      }
      IM_PPIX(timg,i,l,&rcolor);
    }
  }

  for(l=0;l<im->xsize;l++) {
    for(i=0;i<im->ysize;i++) {
      pc=0.0;	
      for(ch=0;ch<im->channels;ch++) res[ch]=0;
      for(c=0;c<len;c++) {
	if (IM_GPIX(timg,l,i+c-center,&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 temp = res[ch]/pc;
	rcolor.channel[ch]= 
	  temp < 0 ? 0 : temp > IM_SAMPLE_MAX ? IM_SAMPLE_MAX : (IM_SAMPLE_T)temp;
      }
      IM_PPIX(im,l,i,&rcolor);
    }
  }
#/code

  i_img_destroy(timg);
}