Thu Oct 19 15:20:51 2006 John Ellis <johne@verizon.net>

[geeqie.git] / src / pixbuf_util.c

diff --git a/src/pixbuf_util.c b/src/pixbuf_util.c
index 047112f..9634245 100644 (file)
--- a/src/pixbuf_util.c
+++ b/src/pixbuf_util.c
@@ -1177,3 +1177,50 @@ void pixbuf_draw_shadow(GdkPixbuf *pb,
 }
 
 
+/*
+ *-----------------------------------------------------------------------------
+ * pixbuf color alterations
+ *-----------------------------------------------------------------------------
+ */
+
+void pixbuf_desaturate_rect(GdkPixbuf *pb,
+                           gint x, gint y, gint w, gint h)
+{
+       gint p_alpha;
+       gint pw, ph, prs;
+       guchar *p_pix;
+       guchar *pp;
+       gint i, j;
+
+       if (!pb) return;
+
+       pw = gdk_pixbuf_get_width(pb);
+       ph = gdk_pixbuf_get_height(pb);
+
+       if (x < 0 || x + w > pw) return;
+       if (y < 0 || y + h > ph) return;
+
+       p_alpha = gdk_pixbuf_get_has_alpha(pb);
+       prs = gdk_pixbuf_get_rowstride(pb);
+       p_pix = gdk_pixbuf_get_pixels(pb);
+
+        for (i = 0; i < h; i++)
+               {
+               pp = p_pix + (y + i) * prs + (x * (p_alpha ? 4 : 3));
+               for (j = 0; j < w; j++)
+                       {
+                       guint8 grey;
+
+                       grey = (pp[0] + pp[1] + pp[2]) / 3;
+                       *pp = grey;
+                       pp++;
+                       *pp = grey;
+                       pp++;
+                       *pp = grey;
+                       pp++;
+                       if (p_alpha) pp++;
+                       }
+               }
+}
+
+