four_corners_best 1708 src/image.c    	= four_corners_best (pimg, img->corners, img->width, img->height);
four_corners_best 1753 src/image.c    	    = (four_corners_best (mask, img->corners, img->width, img->height) == PIX_MASK_RETAIN);
four_corners_best 6604 src/image.c        bg = four_corners_best (ximg, img->corners, img->width, img->height);