2013-07-30 Behdad Esfahbod <behdad@google.com>

Prevent division by zero by a transparent color.

	* src/base/ftbitmap.c (ft_gray_for_premultiplied_srgb_bgra):
	Return 0 immediately, when alpha channel is zero.

ChangeLog

@@ -1,3 +1,10 @@
+2013-07-30  Behdad Esfahbod  <behdad@google.com>
+
+	Prevent division by zero by a transparent color.
+
+	* src/base/ftbitmap.c (ft_gray_for_premultiplied_srgb_bgra):
+	Return 0 immediately, when alpha channel is zero.
+
 2013-07-25  Behdad Esfahbod  <behdad@google.com>
 
 	Add FT_FACE_FLAG_COLOR and FT_HAS_COLOR.

src/base/ftbitmap.c

@@ -385,6 +385,10 @@
     FT_Long  l;
 
 
+    /* Short-circuit transparent color to avoid div-by-zero. */
+    if (!a)
+      return 0;
+
     /*
      * Luminosity for sRGB is defined using ~0.2126,0.7152,0.0722
      * coefficients for RGB channels *on the linear colors*.