1 files changed, 109 insertions, 0 deletions
diff --git a/src/tools/marco-grayscale.c b/src/tools/marco-grayscale.c
new file mode 100644
index 00000000..8d0cd68c
--- /dev/null
+++ b/src/tools/marco-grayscale.c
@@ -0,0 +1,109 @@
+/* Hack for grayscaling an image */
+
+/* 
+ * Copyright (C) 2002 Red Hat Inc.
+ * 
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <math.h>
+
+#define INTENSITY(r, g, b) ((r) * 0.30 + (g) * 0.59 + (b) * 0.11)
+
+static GdkPixbuf*
+grayscale_pixbuf (GdkPixbuf *pixbuf)
+{
+  GdkPixbuf *gray;
+  guchar *pixels;
+  int rowstride;
+  int pixstride;
+  int row;
+  int n_rows;
+  int width;
+  
+  gray = gdk_pixbuf_copy (pixbuf);
+  rowstride = gdk_pixbuf_get_rowstride (gray);
+  pixstride = gdk_pixbuf_get_has_alpha (gray) ? 4 : 3;
+  
+  pixels = gdk_pixbuf_get_pixels (gray);
+  n_rows = gdk_pixbuf_get_height (gray);
+  width = gdk_pixbuf_get_width (gray);
+  
+  row = 0;
+  while (row < n_rows)
+    {
+      guchar *p = pixels + row * rowstride;
+      guchar *end = p + (pixstride * width);
+
+      while (p != end)
+        {
+          double v = INTENSITY (p[0], p[1], p[2]);
+
+          p[0] = (guchar) v;
+          p[1] = (guchar) v;
+          p[2] = (guchar) v;
+          
+          p += pixstride;
+        }
+      
+      ++row;
+    }
+  
+  return gray;
+}
+
+int
+main (int argc, char **argv)
+{
+  GdkPixbuf *pixbuf;
+  GdkPixbuf *gray;
+  GError *err;
+  
+  if (argc != 2)
+    {
+      g_printerr ("specify a single image on the command line\n");
+      return 1;
+    }
+
+  g_type_init ();
+  
+  err = NULL;
+  pixbuf = gdk_pixbuf_new_from_file (argv[1], &err);
+  if (err != NULL)
+    {
+      g_printerr ("failed to load image: %s\n", err->message);
+      g_error_free (err);
+      return 1;
+    }
+
+  gray = grayscale_pixbuf (pixbuf);
+  
+  err = NULL;
+  gdk_pixbuf_save (gray, "grayscale.png", "png", &err, NULL);
+  if (err != NULL)
+    {
+      g_printerr ("failed to save image: %s\n", err->message);
+      g_error_free (err);
+      return 1;
+    }
+
+  g_print ("wrote grayscale.png\n");
+  
+  return 0;
+}