gistfile1.c

#include <netpbm/pam.h>


//int getpx(struct pam *inpam, int currow, int row, int col) {

#define DIST 8

#define min(x,y) ( (x<y) ? (x) : (y) )
#define max(x,y) ( (x>y) ? (x) : (y) )

int main(int argc, char *argv[]) {

    struct pam inpam, outpam;
    tuple * tuplerow;
    unsigned int row;
    unsigned int *data;

    pm_init(argv[0], 0);

    pnm_readpaminit(stdin, &inpam, PAM_STRUCT_SIZE(tuple_type));
    
    data = malloc(inpam.width*inpam.height*inpam.depth*sizeof(unsigned int));

    outpam = inpam; outpam.file = stdout;


    tuplerow = pnm_allocpamrow(&inpam);

    size_t i = 0;
    for (row = 0; row < inpam.height; row++) {
        unsigned int column;
        pnm_readpamrow(&inpam, tuplerow);
        for (column = 0; column < inpam.width; ++column) {
            unsigned int plane;
            for (plane = 0; plane < inpam.depth; ++plane) {
                data[i] = tuplerow[column][plane];
                i++;
            }
        }
    }
    
    unsigned int y;

    pnm_writepaminit(&outpam);
    for (y = 0; y < inpam.height; y++) {
        unsigned int x;
        for (x = 0; x < inpam.width; x++) {
            unsigned int p;
            for (p = 0; p < inpam.depth; p++) {
                unsigned int avg = 0;
                unsigned int avgn = 0;
                unsigned int ay;
                for (ay = max(0,y-DIST); ay < min(inpam.height,y+DIST) ; ay++) {
                    unsigned int ax;
                    for (ax = max(0,x-DIST); ax < min(inpam.width,x+DIST) ; ax++) {
                        avg += data[(ay*inpam.width + ax)*inpam.depth + p];
                        avgn += 1;
                    }
                }
                avg = (!avgn) ? 0 : avg/avgn;
                avg = (avg==0) ? 1 : avg;
                ay = data[(y*inpam.width + x)*inpam.depth + p];
                //fprintf(stderr,"data %d, avg %d\n",ay,avg);
                //if ( ay >= avg*3/2)
                    tuplerow[x][p] = 255*ay/avg;
                //else
                //    tuplerow[x][p] = 0x00;
            }
        }
        fprintf(stderr,"Processing %d\n",y*100/inpam.height);
        pnm_writepamrow(&outpam, tuplerow); 
    }


    pnm_freepamrow(tuplerow);
}