+/* Apply GMASK to GPIX and return a GdkPixbuf with an alpha channel. */
+
+GdkPixbuf *
+xg_get_pixbuf_from_pix_and_mask (gpix, gmask, cmap)
+ GdkPixmap *gpix;
+ GdkPixmap *gmask;
+ GdkColormap *cmap;
+{
+ int x, y, width, height, rowstride, mask_rowstride;
+ GdkPixbuf *icon_buf, *tmp_buf;
+ guchar *pixels;
+ guchar *mask_pixels;
+
+ gdk_drawable_get_size (gpix, &width, &height);
+ tmp_buf = gdk_pixbuf_get_from_drawable (NULL, gpix, cmap,
+ 0, 0, 0, 0, width, height);
+ icon_buf = gdk_pixbuf_add_alpha (tmp_buf, FALSE, 0, 0, 0);
+ g_object_unref (G_OBJECT (tmp_buf));
+
+ if (gmask)
+ {
+ GdkPixbuf *mask_buf = gdk_pixbuf_get_from_drawable (NULL,
+ gmask,
+ NULL,
+ 0, 0, 0, 0,
+ width, height);
+ guchar *pixels = gdk_pixbuf_get_pixels (icon_buf);
+ guchar *mask_pixels = gdk_pixbuf_get_pixels (mask_buf);
+ int rowstride = gdk_pixbuf_get_rowstride (icon_buf);
+ int mask_rowstride = gdk_pixbuf_get_rowstride (mask_buf);
+ int y;
+
+ for (y = 0; y < height; ++y)
+ {
+ guchar *iconptr, *maskptr;
+ int x;
+
+ iconptr = pixels + y * rowstride;
+ maskptr = mask_pixels + y * mask_rowstride;
+
+ for (x = 0; x < width; ++x)
+ {
+ /* In a bitmap, RGB is either 255/255/255 or 0/0/0. Checking
+ just R is sufficient. */
+ if (maskptr[0] == 0)
+ iconptr[3] = 0; /* 0, 1, 2 is R, G, B. 3 is alpha. */
+
+ iconptr += rowstride/width;
+ maskptr += mask_rowstride/width;
+ }
+ }
+
+ g_object_unref (G_OBJECT (mask_buf));
+ }
+
+ return icon_buf;
+}
+