+#include <pam.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <assert.h>
+#include <string.h>
+
+#define eassert assert
+
+typedef struct {
+ unsigned long rgb; /* on screen */
+ char c; /* canonical */
+} CanonColourInfo;
+
+static const CanonColourInfo canoncolourinfos[]= {
+ { 0x475A5E, '*' }, /* edge */
+ { 0x7D9094, '+' }, /* interbox */
+ { 0xBDC5BF, ' ' }, /* background - pale */
+ { 0xADB5AF, ' ' }, /* background - dark */
+ { 0x000000, 'o' }, /* foreground */
+ { 0xD4B356, ' ' }, /* background (cursor) */
+ { 0xFFFFFF, 'o' }, /* foreground (cursor) */
+ { 0,0 }
+};
+
+static int height, width;
+static char *image;
+
+static void load_image_and_canonify(void) {
+ struct pam inpam;
+ unsigned char rgb[3];
+ int x,y,r;
+ const CanonColourInfo *cci;
+
+ pnm_readpaminit(stdin, &inpam, sizeof(inpam));
+ height= inpam.height;
+ width= inpam.width;
+ eassert(inpam.maxval == 255);
+ eassert(inpam.bytes_per_sample == 1);
+
+ image= malloc(width*height);
+ eassert(image);
+ memset(image,'?',width*height);
+
+ for (y=0; y<height; y++) {
+ for (x=0; x<width; x++) {
+ r= fread(&rgb,1,3,stdin); eassert(r==3);
+ unsigned long rgb_l=
+ ((unsigned long)rgb[0]<<16) |
+ ((unsigned long)rgb[1]<<8) |
+ (rgb[2]);
+ for (cci=canoncolourinfos; cci->c; cci++)
+ if (cci->rgb == rgb_l) {
+ image[y*width + x]= cci->c;
+ break;
+ }
+ if (y==234 && x==82) {
+ printf("y=%d/%d x=%d/%d rgb=%d,%d,%d rgb_l=%lx c=%c\n",
+ y,height,x,width, rgb[0],rgb[1],rgb[2], rgb_l, image[y*width+x]);
+ }
+ }
+ r= fwrite(image + y*width, 1,width, stdout); eassert(r==width);
+ putchar('\n');
+ }
+ eassert(!fflush(stdout));
+ eassert(!ferror(stdout));
+}
+
+int main(void) {
+ load_image_and_canonify();
+ /*
+ find_main_rectangle();
+ repeatedly_find_top_thing();
+ */
+ return 0;
+}