wimmel: Convert to calculation on monochrome image

1 files changed, 21 insertions, 3 deletions

diff --git a/wimmel.c b/wimmel.c
index 69daa11..4f55f4e 100644
--- a/wimmel.c
+++ b/wimmel.c
@@ -40,9 +40,7 @@ find_image_in_wimmel(GdkPixbuf *wimmel, GdkPixbuf *match, GdkPixbuf *output)
 
 					pix = row + n * stride + (i + k) * nch;
 
-					if (abs((int)pix[0] - (int)pix_m[0]) > 50 ||
-					    abs((int)pix[1] - (int)pix_m[1]) > 50 ||
-					    abs((int)pix[2] - (int)pix_m[2]) > 50) {
+					if (abs((int)pix[0] - (int)pix_m[0]) > 10) {
 						difference++;
 						if (difference > barrier)
 							break;
@@ -86,6 +84,24 @@ find_thread(gpointer data)
 	return NULL;
 }
 
+void
+monochrome(GdkPixbuf *p)
+{
+	int x, y, width, height, nch;
+	guchar *d;
+
+	width = gdk_pixbuf_get_width(p);
+	height = gdk_pixbuf_get_height(p);
+	nch = gdk_pixbuf_get_n_channels(p);
+
+	for (y = 0; y < height; ++y) {
+		d = gdk_pixbuf_get_pixels(p) + y * gdk_pixbuf_get_rowstride(p);
+		for (x = 0; x < width; ++x, d += nch) {
+			d[0] = MAX(d[0], MAX(d[1], d[2]));
+		}
+	}
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -112,10 +128,12 @@ main(int argc, char *argv[])
 		exit(EXIT_FAILURE);
 
 	output = gdk_pixbuf_copy(wimmel);
+	monochrome(wimmel);
 
 	match_tmp = gdk_pixbuf_new_subpixbuf(wimmel, x1, y1, mwidth, mheight);
 	match = gdk_pixbuf_copy(match_tmp);
 	g_object_unref(match_tmp);
+	monochrome(match);
 
 	width = gdk_pixbuf_get_width(wimmel);
 	height = gdk_pixbuf_get_height(wimmel);