[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).

1 files changed, 1 insertions, 0 deletions

diff --git a/pngread.c b/pngread.c
index c658a4692..ab01cae13 100644
--- a/pngread.c
+++ b/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;
          }