get_valid_rect
bool get_valid_rect(BBitmap *bitmap, RECT *rc);
if (get_valid_rect(bitmap, &rc)) {
if (get_valid_rect(bitmap, &rc)) {
if (get_valid_rect(bitmap, &rc)) {
if (get_valid_rect(bitmap, &rc)) {
if (!get_valid_rect(bitmap, &fBounds))
if (get_valid_rect(bitmap, &rc)) {