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#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) > (b) ? (a) : (b))
typedef struct {
int x0;
int x1;
int y0;
int y1;
double xmom;
double ymom;
int area;
} seg;
typedef struct {
int x0;
int x1;
} run;
void
find_runs(run *result, const unsigned char *buf, unsigned char thresh, int xs)
{
int x;
int j = 0;
for (x = 0; x < xs;) {
int x0, x1;
for (x0 = x; x0 < xs; x0++)
if (buf[x0] < thresh)
break;
if (x0 == xs)
break;
for (x1 = x0 + 1; x1 < xs; x1++)
if (buf[x1] >= thresh)
break;
result[j].x0 = x0;
result[j].x1 = x1;
j++;
x = x1 + 1;
}
result[j].x0 = 0;
result[j].x1 = 0;
}
void
print_rect(const seg *r)
{
printf("%d %d %d %d %g rect\n", r->x0, r->y0, r->x1, r->y1,
r->area / (1.0 * (r->x1 - r->x0) * (r->y1 - r->y0)));
printf("%g %g ci\n", r->xmom / r->area, r->ymom / r->area);
}
void
merge_runs(seg *buf, const run *new_runs, int y)
{
int bi, ni;
int bs;
int bi0;
int flag;
for (bs = 0; buf[bs].x1; bs++);
bi = 0;
flag = 1;
for (ni = 0; new_runs[ni].x1; ni++) {
int run_len = new_runs[ni].x1 - new_runs[ni].x0;
bi0 = bi;
for (; bi < bs && buf[bi].x1 <= new_runs[ni].x0; bi++) {
if (flag) {
buf[bi].y1 = y;
print_rect(&buf[bi]);
} else {
bi0 = bi + 1;
flag = 1;
}
}
if (bi > bi0) {
memmove(&buf[bi0], &buf[bi], (bs - bi) * sizeof(seg));
bs += bi0 - bi;
}
bi = bi0;
if (bi < bs && buf[bi].x0 < new_runs[ni].x1) {
double xmom = buf[bi].xmom;
double ymom = buf[bi].ymom;
int area = buf[bi].area;
int y0 = buf[bi].y0;
for (bi = bi + 1; bi < bs && buf[bi].x0 < new_runs[ni].x1; bi++) {
y0 = MIN(y0, buf[bi].y0);
xmom += buf[bi].xmom;
ymom += buf[bi].ymom;
area += buf[bi].area;
}
buf[bi0].x0 = MIN(buf[bi0].x0, new_runs[ni].x0);
buf[bi0].x1 = MAX(buf[bi - 1].x1, new_runs[ni].x1);
buf[bi0].y0 = y0;
buf[bi0].xmom = xmom + run_len * .5 * (new_runs[ni].x0 + new_runs[ni].x1);
buf[bi0].ymom = ymom + run_len * y;
buf[bi0].area = area + run_len;
if (bi > bi0 + 1) {
memmove(&buf[bi0 + 1], &buf[bi], (bs - bi) * sizeof(seg));
bs += bi0 + 1 - bi;
}
bi = bi0;
flag = 0;
} else {
memmove(&buf[bi + 1], &buf[bi], (bs - bi) * sizeof(seg));
bs++;
buf[bi].x0 = new_runs[ni].x0;
buf[bi].x1 = new_runs[ni].x1;
buf[bi].y0 = y;
buf[bi].xmom = run_len * .5 * (new_runs[ni].x0 + new_runs[ni].x1);
buf[bi].ymom = run_len * y;
buf[bi].area = run_len;
bi++;
flag = 1;
}
}
bi0 = bi;
for (; bi < bs; bi++) {
if (flag) {
buf[bi].y1 = y;
print_rect(&buf[bi]);
} else {
bi0 = bi + 1;
flag = 1;
}
}
buf[bi0].x0 = 0;
buf[bi0].x1 = 0;
}
static void
die (char *why)
{
fprintf (stderr, "%s\n", why);
exit (1);
}
#define MAX_SIZE 65536
int
main (int argc, char **argv)
{
FILE *fi = stdin;
FILE *fo = stdout;
char buf[256];
int xs, ys;
int depth;
unsigned char *imgbuf;
seg *segs;
run *runs;
int y;
fgets (buf, sizeof(buf), fi);
if (buf[0] != 'P' || buf[1] != '5')
die ("Need pgmraw image on input");
xs = ys = 0;
do
fgets (buf, sizeof(buf), fi);
while (buf[0] == '#');
sscanf (buf, "%d %d", &xs, &ys);
if (xs <= 0 || ys <= 0 || xs > MAX_SIZE || ys > MAX_SIZE)
die ("Input image size out of range");
do
fgets (buf, sizeof(buf), fi);
while (buf[0] == '#');
sscanf (buf, "%d", &depth);
if (depth != 255)
die ("Only works with depth=255 images");
runs = (run *)malloc(((xs + 3) >> 1) * sizeof(run));
segs = (seg *)malloc(((xs + 3) >> 1) * sizeof(seg));
imgbuf = (unsigned char *)malloc (xs);
segs[0].x0 = 0;
segs[0].x1 = 0;
for (y = 0; y < ys; y++) {
fread (imgbuf, 1, xs, fi);
find_runs(runs, imgbuf, 160, xs);
merge_runs(segs, runs, y);
}
free(imgbuf);
free(runs);
free(segs);
return 0;
}
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