+
+static void fwrite_ppm(FILE *f, const RgbImage *base, Rect portion) {
+ int x,y,i;
+ fprintf(f,"P3\n%d %d\n255\n", RECT_W(portion), RECT_H(portion));
+ for (y=portion.tl.y; y<=portion.br.y; y++) {
+ for (x=portion.tl.x; x<=portion.br.x; x++) {
+ putc(' ',f);
+ for (i=0; i<3; i++)
+ fprintf(f," %3d", RI_PIXEL(base,x,y)[i]);
+ }
+ putc('\n',f);
+ }
+ sysassert(!ferror(f));
+ sysassert(!fflush(f));
+}
+