[libpng16] Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha

value was wrong.  It's not clear if this affected the final stored
value; in the obvious code path the upper and lower 8-bits of the
alpha value were identical and the alpha was truncated to 8-bits
rather than dividing by 257 (John Bowler).

ANNOUNCE

-Libpng 1.6.17rc06 - March 21, 2015
+Libpng 1.6.17rc06 - March 23, 2015
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -92,8 +92,14 @@ Version 1.6.17rc05 [March 21, 2015]
   Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
     the Coverity scan without them.
 
-Version 1.6.17rc06 [March 21, 2015]
+Version 1.6.17rc06 [March 23, 2015]
   Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
+  Reformatted some "&0xff" instances to "& 0xff".
+  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
+    value was wrong.  It's not clear if this affected the final stored
+    value; in the obvious code path the upper and lower 8-bits of the
+    alpha value were identical and the alpha was truncated to 8-bits
+    rather than dividing by 257 (John Bowler).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CHANGES

@@ -5193,8 +5193,14 @@ Version 1.6.17rc05 [March 21, 2015]
   Reverted "& 0xff" additions of version 1.6.17beta01. Libpng passes
     the Coverity scan without them.
 
-Version 1.6.17rc06 [March 21, 2015]
+Version 1.6.17rc06 [March 23, 2015]
   Remove pnglibconf.dfn and pnglibconf.pre with "make clean".
+  Reformatted some "&0xff" instances to "& 0xff".
+  Fixed simplified 8-bit-linear to sRGB alpha. The calculated alpha
+    value was wrong.  It's not clear if this affected the final stored
+    value; in the obvious code path the upper and lower 8-bits of the
+    alpha value were identical and the alpha was truncated to 8-bits
+    rather than dividing by 257 (John Bowler).
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

pngread.c

@@ -1823,6 +1823,7 @@ png_create_colormap_entry(png_image_read_control *display,
             y = (y + 128) >> 8;
             y *= 255;
             y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
+            alpha = PNG_DIV257(alpha);
             encoding = P_sRGB;
          }