[libpng16] Removed some unnecessary brackets in pngrtran.c
diff --git a/ANNOUNCE b/ANNOUNCE
index 7ff9c6a..ad9c5d5 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -1,4 +1,4 @@
-Libpng 1.6.35beta01 - October 29, 2017
+Libpng 1.6.35beta01 - November 1, 2017
 
 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.
@@ -24,12 +24,12 @@
 
 Changes since the last public release (1.6.34):
 
-Version 1.6.35beta01 [October 29, 2017]
+Version 1.6.35beta01 [November 1, 2017]
   Restored 21 of the contrib/pngsuite/i*.png, which do not cause test
     failures. Placed the remainder in contrib/pngsuite/interlaced/i*.png.
   Added calls to png_set_*() transforms commonly used by browsers to
     the fuzzer.
-  Initialize trans_color.red, green, and blue == trans_color.gray
+  Removed some unnecessary brackets in pngrtran.c
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 274e41a..834568a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -6038,14 +6038,14 @@
   Add end_info structure and png_read_end() to the libpng fuzzer.
 
 Version 1.6.34 [September 29, 2017]
-  Removed contrib/pngsuite/i*.png; some of caused test failures.
+  Removed contrib/pngsuite/i*.png; some of them caused test failures.
 
-Version 1.6.35beta01 [October 29, 2017]
+Version 1.6.35beta01 [November 1, 2017]
   Restored 21 of the contrib/pngsuite/i*.png, which do not cause test
     failures. Placed the remainder in contrib/pngsuite/interlaced/i*.png.
   Added calls to png_set_*() transforms commonly used by browsers to
     the fuzzer.
-  Initialize trans_color.red, green, and blue == trans_color.gray
+  Removed some unnecessary brackets in pngrtran.c
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/pngrtran.c b/pngrtran.c
index c189650..a394a54 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,7 +1,7 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Last changed in libpng 1.6.33 [September 28, 2017]
+ * Last changed in libpng 1.6.35 [(PENDING RELEASE)]
  * Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -2463,95 +2463,94 @@
 static void
 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 {
+   png_uint_32 row_width = row_info->width;
+
    png_debug(1, "in png_do_read_swap_alpha");
 
+   if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
    {
-      png_uint_32 row_width = row_info->width;
-      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      /* This converts from RGBA to ARGB */
+      if (row_info->bit_depth == 8)
       {
-         /* This converts from RGBA to ARGB */
-         if (row_info->bit_depth == 8)
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
          {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save;
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               save = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save;
-            }
+            save = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save;
          }
-
-#ifdef PNG_READ_16BIT_SUPPORTED
-         /* This converts from RRGGBBAA to AARRGGBB */
-         else
-         {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save[2];
-            png_uint_32 i;
-
-            for (i = 0; i < row_width; i++)
-            {
-               save[0] = *(--sp);
-               save[1] = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save[0];
-               *(--dp) = save[1];
-            }
-         }
-#endif
       }
 
-      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+#ifdef PNG_READ_16BIT_SUPPORTED
+      /* This converts from RRGGBBAA to AARRGGBB */
+      else
       {
-         /* This converts from GA to AG */
-         if (row_info->bit_depth == 8)
-         {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save;
-            png_uint_32 i;
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save[2];
+         png_uint_32 i;
 
-            for (i = 0; i < row_width; i++)
-            {
-               save = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save;
-            }
+         for (i = 0; i < row_width; i++)
+         {
+            save[0] = *(--sp);
+            save[1] = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save[0];
+            *(--dp) = save[1];
          }
+      }
+#endif
+   }
+
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+   {
+      /* This converts from GA to AG */
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save;
+         png_uint_32 i;
+
+         for (i = 0; i < row_width; i++)
+         {
+            save = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save;
+         }
+      }
 
 #ifdef PNG_READ_16BIT_SUPPORTED
-         /* This converts from GGAA to AAGG */
-         else
-         {
-            png_bytep sp = row + row_info->rowbytes;
-            png_bytep dp = sp;
-            png_byte save[2];
-            png_uint_32 i;
+      /* This converts from GGAA to AAGG */
+      else
+      {
+         png_bytep sp = row + row_info->rowbytes;
+         png_bytep dp = sp;
+         png_byte save[2];
+         png_uint_32 i;
 
-            for (i = 0; i < row_width; i++)
-            {
-               save[0] = *(--sp);
-               save[1] = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = *(--sp);
-               *(--dp) = save[0];
-               *(--dp) = save[1];
-            }
+         for (i = 0; i < row_width; i++)
+         {
+            save[0] = *(--sp);
+            save[1] = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = *(--sp);
+            *(--dp) = save[0];
+            *(--dp) = save[1];
          }
-#endif
       }
+#endif
    }
 }
 #endif
@@ -3209,419 +3208,229 @@
 
    png_debug(1, "in png_do_compose");
 
+   switch (row_info->color_type)
    {
-      switch (row_info->color_type)
+      case PNG_COLOR_TYPE_GRAY:
       {
-         case PNG_COLOR_TYPE_GRAY:
+         switch (row_info->bit_depth)
          {
-            switch (row_info->bit_depth)
+            case 1:
             {
-               case 1:
+               sp = row;
+               shift = 7;
+               for (i = 0; i < row_width; i++)
                {
-                  sp = row;
-                  shift = 7;
-                  for (i = 0; i < row_width; i++)
+                  if ((png_uint_16)((*sp >> shift) & 0x01)
+                     == png_ptr->trans_color.gray)
                   {
-                     if ((png_uint_16)((*sp >> shift) & 0x01)
-                        == png_ptr->trans_color.gray)
-                     {
-                        unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
-                        tmp |=
-                            (unsigned int)(png_ptr->background.gray << shift);
-                        *sp = (png_byte)(tmp & 0xff);
-                     }
-
-                     if (shift == 0)
-                     {
-                        shift = 7;
-                        sp++;
-                     }
-
-                     else
-                        shift--;
+                     unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
+                     tmp |=
+                         (unsigned int)(png_ptr->background.gray << shift);
+                     *sp = (png_byte)(tmp & 0xff);
                   }
-                  break;
-               }
 
-               case 2:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_table != NULL)
+                  if (shift == 0)
                   {
-                     sp = row;
-                     shift = 6;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x03)
-                            == png_ptr->trans_color.gray)
-                        {
-                           unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
-                           tmp |=
-                              (unsigned int)png_ptr->background.gray << shift;
-                           *sp = (png_byte)(tmp & 0xff);
-                        }
-
-                        else
-                        {
-                           unsigned int p = (*sp >> shift) & 0x03;
-                           unsigned int g = (gamma_table [p | (p << 2) |
-                               (p << 4) | (p << 6)] >> 6) & 0x03;
-                           unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
-                           tmp |= (unsigned int)(g << shift);
-                           *sp = (png_byte)(tmp & 0xff);
-                        }
-
-                        if (shift == 0)
-                        {
-                           shift = 6;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 2;
-                     }
+                     shift = 7;
+                     sp++;
                   }
 
                   else
-#endif
-                  {
-                     sp = row;
-                     shift = 6;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x03)
-                            == png_ptr->trans_color.gray)
-                        {
-                           unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
-                           tmp |=
-                               (unsigned int)png_ptr->background.gray << shift;
-                           *sp = (png_byte)(tmp & 0xff);
-                        }
-
-                        if (shift == 0)
-                        {
-                           shift = 6;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 2;
-                     }
-                  }
-                  break;
+                     shift--;
                }
-
-               case 4:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_table != NULL)
-                  {
-                     sp = row;
-                     shift = 4;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x0f)
-                            == png_ptr->trans_color.gray)
-                        {
-                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
-                           tmp |=
-                              (unsigned int)(png_ptr->background.gray << shift);
-                           *sp = (png_byte)(tmp & 0xff);
-                        }
-
-                        else
-                        {
-                           unsigned int p = (*sp >> shift) & 0x0f;
-                           unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
-                              0x0f;
-                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
-                           tmp |= (unsigned int)(g << shift);
-                           *sp = (png_byte)(tmp & 0xff);
-                        }
-
-                        if (shift == 0)
-                        {
-                           shift = 4;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 4;
-                     }
-                  }
-
-                  else
-#endif
-                  {
-                     sp = row;
-                     shift = 4;
-                     for (i = 0; i < row_width; i++)
-                     {
-                        if ((png_uint_16)((*sp >> shift) & 0x0f)
-                            == png_ptr->trans_color.gray)
-                        {
-                           unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
-                           tmp |=
-                              (unsigned int)(png_ptr->background.gray << shift);
-                           *sp = (png_byte)(tmp & 0xff);
-                        }
-
-                        if (shift == 0)
-                        {
-                           shift = 4;
-                           sp++;
-                        }
-
-                        else
-                           shift -= 4;
-                     }
-                  }
-                  break;
-               }
-
-               case 8:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_table != NULL)
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp++)
-                     {
-                        if (*sp == png_ptr->trans_color.gray)
-                           *sp = (png_byte)png_ptr->background.gray;
-
-                        else
-                           *sp = gamma_table[*sp];
-                     }
-                  }
-                  else
-#endif
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp++)
-                     {
-                        if (*sp == png_ptr->trans_color.gray)
-                           *sp = (png_byte)png_ptr->background.gray;
-                     }
-                  }
-                  break;
-               }
-
-               case 16:
-               {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-                  if (gamma_16 != NULL)
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp += 2)
-                     {
-                        png_uint_16 v;
-
-                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                        if (v == png_ptr->trans_color.gray)
-                        {
-                           /* Background is already in screen gamma */
-                           *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                           *(sp + 1) = (png_byte)(png_ptr->background.gray
-                                & 0xff);
-                        }
-
-                        else
-                        {
-                           v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                           *sp = (png_byte)((v >> 8) & 0xff);
-                           *(sp + 1) = (png_byte)(v & 0xff);
-                        }
-                     }
-                  }
-                  else
-#endif
-                  {
-                     sp = row;
-                     for (i = 0; i < row_width; i++, sp += 2)
-                     {
-                        png_uint_16 v;
-
-                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                        if (v == png_ptr->trans_color.gray)
-                        {
-                           *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                           *(sp + 1) = (png_byte)(png_ptr->background.gray
-                                & 0xff);
-                        }
-                     }
-                  }
-                  break;
-               }
-
-               default:
-                  break;
+               break;
             }
-            break;
-         }
 
-         case PNG_COLOR_TYPE_RGB:
-         {
-            if (row_info->bit_depth == 8)
+            case 2:
             {
 #ifdef PNG_READ_GAMMA_SUPPORTED
                if (gamma_table != NULL)
                {
                   sp = row;
-                  for (i = 0; i < row_width; i++, sp += 3)
+                  shift = 6;
+                  for (i = 0; i < row_width; i++)
                   {
-                     if (*sp == png_ptr->trans_color.red &&
-                         *(sp + 1) == png_ptr->trans_color.green &&
-                         *(sp + 2) == png_ptr->trans_color.blue)
+                     if ((png_uint_16)((*sp >> shift) & 0x03)
+                         == png_ptr->trans_color.gray)
                      {
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |=
+                           (unsigned int)png_ptr->background.gray << shift;
+                        *sp = (png_byte)(tmp & 0xff);
                      }
 
                      else
                      {
-                        *sp = gamma_table[*sp];
-                        *(sp + 1) = gamma_table[*(sp + 1)];
-                        *(sp + 2) = gamma_table[*(sp + 2)];
+                        unsigned int p = (*sp >> shift) & 0x03;
+                        unsigned int g = (gamma_table [p | (p << 2) |
+                            (p << 4) | (p << 6)] >> 6) & 0x03;
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |= (unsigned int)(g << shift);
+                        *sp = (png_byte)(tmp & 0xff);
                      }
+
+                     if (shift == 0)
+                     {
+                        shift = 6;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 2;
+                  }
+               }
+
+               else
+#endif
+               {
+                  sp = row;
+                  shift = 6;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x03)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
+                        tmp |=
+                            (unsigned int)png_ptr->background.gray << shift;
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 6;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 2;
+                  }
+               }
+               break;
+            }
+
+            case 4:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  shift = 4;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x0f)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |=
+                           (unsigned int)(png_ptr->background.gray << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     else
+                     {
+                        unsigned int p = (*sp >> shift) & 0x0f;
+                        unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
+                           0x0f;
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |= (unsigned int)(g << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 4;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 4;
+                  }
+               }
+
+               else
+#endif
+               {
+                  sp = row;
+                  shift = 4;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x0f)
+                         == png_ptr->trans_color.gray)
+                     {
+                        unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
+                        tmp |=
+                           (unsigned int)(png_ptr->background.gray << shift);
+                        *sp = (png_byte)(tmp & 0xff);
+                     }
+
+                     if (shift == 0)
+                     {
+                        shift = 4;
+                        sp++;
+                     }
+
+                     else
+                        shift -= 4;
+                  }
+               }
+               break;
+            }
+
+            case 8:
+            {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp++)
+                  {
+                     if (*sp == png_ptr->trans_color.gray)
+                        *sp = (png_byte)png_ptr->background.gray;
+
+                     else
+                        *sp = gamma_table[*sp];
                   }
                }
                else
 #endif
                {
                   sp = row;
-                  for (i = 0; i < row_width; i++, sp += 3)
+                  for (i = 0; i < row_width; i++, sp++)
                   {
-                     if (*sp == png_ptr->trans_color.red &&
-                         *(sp + 1) == png_ptr->trans_color.green &&
-                         *(sp + 2) == png_ptr->trans_color.blue)
-                     {
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
-                     }
+                     if (*sp == png_ptr->trans_color.gray)
+                        *sp = (png_byte)png_ptr->background.gray;
                   }
                }
+               break;
             }
-            else /* if (row_info->bit_depth == 16) */
+
+            case 16:
             {
 #ifdef PNG_READ_GAMMA_SUPPORTED
                if (gamma_16 != NULL)
                {
                   sp = row;
-                  for (i = 0; i < row_width; i++, sp += 6)
-                  {
-                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                     png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
-                         + *(sp + 5));
-
-                     if (r == png_ptr->trans_color.red &&
-                         g == png_ptr->trans_color.green &&
-                         b == png_ptr->trans_color.blue)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-
-                     else
-                     {
-                        png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
-                        *(sp + 2) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
-                        *(sp + 4) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(v & 0xff);
-                     }
-                  }
-               }
-
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 6)
-                  {
-                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-
-                     png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
-                         + *(sp + 5));
-
-                     if (r == png_ptr->trans_color.red &&
-                         g == png_ptr->trans_color.green &&
-                         b == png_ptr->trans_color.blue)
-                     {
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-                  }
-               }
-            }
-            break;
-         }
-
-         case PNG_COLOR_TYPE_GRAY_ALPHA:
-         {
-            if (row_info->bit_depth == 8)
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
-                   gamma_table != NULL)
-               {
-                  sp = row;
                   for (i = 0; i < row_width; i++, sp += 2)
                   {
-                     png_uint_16 a = *(sp + 1);
+                     png_uint_16 v;
 
-                     if (a == 0xff)
-                        *sp = gamma_table[*sp];
+                     v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
 
-                     else if (a == 0)
+                     if (v == png_ptr->trans_color.gray)
                      {
                         /* Background is already in screen gamma */
-                        *sp = (png_byte)png_ptr->background.gray;
+                        *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                        *(sp + 1) = (png_byte)(png_ptr->background.gray
+                             & 0xff);
                      }
 
                      else
                      {
-                        png_byte v, w;
-
-                        v = gamma_to_1[*sp];
-                        png_composite(w, v, a, png_ptr->background_1.gray);
-                        if (optimize == 0)
-                           w = gamma_from_1[w];
-                        *sp = w;
+                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                        *sp = (png_byte)((v >> 8) & 0xff);
+                        *(sp + 1) = (png_byte)(v & 0xff);
                      }
                   }
                }
@@ -3631,298 +3440,486 @@
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 2)
                   {
-                     png_byte a = *(sp + 1);
+                     png_uint_16 v;
 
-                     if (a == 0)
-                        *sp = (png_byte)png_ptr->background.gray;
+                     v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
 
-                     else if (a < 0xff)
-                        png_composite(*sp, *sp, a, png_ptr->background.gray);
-                  }
-               }
-            }
-            else /* if (png_ptr->bit_depth == 16) */
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
-                   gamma_16_to_1 != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     if (a == (png_uint_16)0xffff)
-                     {
-                        png_uint_16 v;
-
-                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-                     }
-
-                     else if (a == 0)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
-                     }
-
-                     else
-                     {
-                        png_uint_16 g, v, w;
-
-                        g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
-                        png_composite_16(v, g, a, png_ptr->background_1.gray);
-                        if (optimize != 0)
-                           w = v;
-                        else
-                           w = gamma_16_from_1[(v & 0xff) >>
-                               gamma_shift][v >> 8];
-                        *sp = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(w & 0xff);
-                     }
-                  }
-               }
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
-                         + *(sp + 3));
-
-                     if (a == 0)
+                     if (v == png_ptr->trans_color.gray)
                      {
                         *sp = (png_byte)((png_ptr->background.gray >> 8)
-                                & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
-                     }
-
-                     else if (a < 0xffff)
-                     {
-                        png_uint_16 g, v;
-
-                        g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-                        png_composite_16(v, g, a, png_ptr->background.gray);
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
+                             & 0xff);
+                        *(sp + 1) = (png_byte)(png_ptr->background.gray
+                             & 0xff);
                      }
                   }
                }
+               break;
             }
-            break;
+
+            default:
+               break;
          }
-
-         case PNG_COLOR_TYPE_RGB_ALPHA:
-         {
-            if (row_info->bit_depth == 8)
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
-                   gamma_table != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_byte a = *(sp + 3);
-
-                     if (a == 0xff)
-                     {
-                        *sp = gamma_table[*sp];
-                        *(sp + 1) = gamma_table[*(sp + 1)];
-                        *(sp + 2) = gamma_table[*(sp + 2)];
-                     }
-
-                     else if (a == 0)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
-                     }
-
-                     else
-                     {
-                        png_byte v, w;
-
-                        v = gamma_to_1[*sp];
-                        png_composite(w, v, a, png_ptr->background_1.red);
-                        if (optimize == 0) w = gamma_from_1[w];
-                        *sp = w;
-
-                        v = gamma_to_1[*(sp + 1)];
-                        png_composite(w, v, a, png_ptr->background_1.green);
-                        if (optimize == 0) w = gamma_from_1[w];
-                        *(sp + 1) = w;
-
-                        v = gamma_to_1[*(sp + 2)];
-                        png_composite(w, v, a, png_ptr->background_1.blue);
-                        if (optimize == 0) w = gamma_from_1[w];
-                        *(sp + 2) = w;
-                     }
-                  }
-               }
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 4)
-                  {
-                     png_byte a = *(sp + 3);
-
-                     if (a == 0)
-                     {
-                        *sp = (png_byte)png_ptr->background.red;
-                        *(sp + 1) = (png_byte)png_ptr->background.green;
-                        *(sp + 2) = (png_byte)png_ptr->background.blue;
-                     }
-
-                     else if (a < 0xff)
-                     {
-                        png_composite(*sp, *sp, a, png_ptr->background.red);
-
-                        png_composite(*(sp + 1), *(sp + 1), a,
-                            png_ptr->background.green);
-
-                        png_composite(*(sp + 2), *(sp + 2), a,
-                            png_ptr->background.blue);
-                     }
-                  }
-               }
-            }
-            else /* if (row_info->bit_depth == 16) */
-            {
-#ifdef PNG_READ_GAMMA_SUPPORTED
-               if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
-                   gamma_16_to_1 != NULL)
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 8)
-                  {
-                     png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
-                         << 8) + (png_uint_16)(*(sp + 7)));
-
-                     if (a == (png_uint_16)0xffff)
-                     {
-                        png_uint_16 v;
-
-                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
-                        *(sp + 2) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(v & 0xff);
-
-                        v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
-                        *(sp + 4) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(v & 0xff);
-                     }
-
-                     else if (a == 0)
-                     {
-                        /* Background is already in screen gamma */
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-
-                     else
-                     {
-                        png_uint_16 v, w;
-
-                        v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
-                        png_composite_16(w, v, a, png_ptr->background_1.red);
-                        if (optimize == 0)
-                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
-                                8];
-                        *sp = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(w & 0xff);
-
-                        v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
-                        png_composite_16(w, v, a, png_ptr->background_1.green);
-                        if (optimize == 0)
-                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
-                                8];
-
-                        *(sp + 2) = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(w & 0xff);
-
-                        v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
-                        png_composite_16(w, v, a, png_ptr->background_1.blue);
-                        if (optimize == 0)
-                           w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
-                                8];
-
-                        *(sp + 4) = (png_byte)((w >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(w & 0xff);
-                     }
-                  }
-               }
-
-               else
-#endif
-               {
-                  sp = row;
-                  for (i = 0; i < row_width; i++, sp += 8)
-                  {
-                     png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
-                         << 8) + (png_uint_16)(*(sp + 7)));
-
-                     if (a == 0)
-                     {
-                        *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
-                        *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
-                                & 0xff);
-                        *(sp + 3) = (png_byte)(png_ptr->background.green
-                                & 0xff);
-                        *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
-                                & 0xff);
-                        *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
-                     }
-
-                     else if (a < 0xffff)
-                     {
-                        png_uint_16 v;
-
-                        png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
-                        png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
-                            + *(sp + 3));
-                        png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
-                            + *(sp + 5));
-
-                        png_composite_16(v, r, a, png_ptr->background.red);
-                        *sp = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 1) = (png_byte)(v & 0xff);
-
-                        png_composite_16(v, g, a, png_ptr->background.green);
-                        *(sp + 2) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 3) = (png_byte)(v & 0xff);
-
-                        png_composite_16(v, b, a, png_ptr->background.blue);
-                        *(sp + 4) = (png_byte)((v >> 8) & 0xff);
-                        *(sp + 5) = (png_byte)(v & 0xff);
-                     }
-                  }
-               }
-            }
-            break;
-         }
-
-         default:
-            break;
+         break;
       }
+
+      case PNG_COLOR_TYPE_RGB:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 3)
+               {
+                  if (*sp == png_ptr->trans_color.red &&
+                      *(sp + 1) == png_ptr->trans_color.green &&
+                      *(sp + 2) == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else
+                  {
+                     *sp = gamma_table[*sp];
+                     *(sp + 1) = gamma_table[*(sp + 1)];
+                     *(sp + 2) = gamma_table[*(sp + 2)];
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 3)
+               {
+                  if (*sp == png_ptr->trans_color.red &&
+                      *(sp + 1) == png_ptr->trans_color.green &&
+                      *(sp + 2) == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+               }
+            }
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 6)
+               {
+                  png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                  png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                      + *(sp + 5));
+
+                  if (r == png_ptr->trans_color.red &&
+                      g == png_ptr->trans_color.green &&
+                      b == png_ptr->trans_color.blue)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 6)
+               {
+                  png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+
+                  png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                      + *(sp + 5));
+
+                  if (r == png_ptr->trans_color.red &&
+                      g == png_ptr->trans_color.green &&
+                      b == png_ptr->trans_color.blue)
+                  {
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 2)
+               {
+                  png_uint_16 a = *(sp + 1);
+
+                  if (a == 0xff)
+                     *sp = gamma_table[*sp];
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)png_ptr->background.gray;
+                  }
+
+                  else
+                  {
+                     png_byte v, w;
+
+                     v = gamma_to_1[*sp];
+                     png_composite(w, v, a, png_ptr->background_1.gray);
+                     if (optimize == 0)
+                        w = gamma_from_1[w];
+                     *sp = w;
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 2)
+               {
+                  png_byte a = *(sp + 1);
+
+                  if (a == 0)
+                     *sp = (png_byte)png_ptr->background.gray;
+
+                  else if (a < 0xff)
+                     png_composite(*sp, *sp, a, png_ptr->background.gray);
+               }
+            }
+         }
+         else /* if (png_ptr->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                gamma_16_to_1 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  if (a == (png_uint_16)0xffff)
+                  {
+                     png_uint_16 v;
+
+                     v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 g, v, w;
+
+                     g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                     png_composite_16(v, g, a, png_ptr->background_1.gray);
+                     if (optimize != 0)
+                        w = v;
+                     else
+                        w = gamma_16_from_1[(v & 0xff) >>
+                            gamma_shift][v >> 8];
+                     *sp = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(w & 0xff);
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
+                      + *(sp + 3));
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)((png_ptr->background.gray >> 8)
+                             & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
+                  }
+
+                  else if (a < 0xffff)
+                  {
+                     png_uint_16 g, v;
+
+                     g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_composite_16(v, g, a, png_ptr->background.gray);
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+      {
+         if (row_info->bit_depth == 8)
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                gamma_table != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_byte a = *(sp + 3);
+
+                  if (a == 0xff)
+                  {
+                     *sp = gamma_table[*sp];
+                     *(sp + 1) = gamma_table[*(sp + 1)];
+                     *(sp + 2) = gamma_table[*(sp + 2)];
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else
+                  {
+                     png_byte v, w;
+
+                     v = gamma_to_1[*sp];
+                     png_composite(w, v, a, png_ptr->background_1.red);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *sp = w;
+
+                     v = gamma_to_1[*(sp + 1)];
+                     png_composite(w, v, a, png_ptr->background_1.green);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *(sp + 1) = w;
+
+                     v = gamma_to_1[*(sp + 2)];
+                     png_composite(w, v, a, png_ptr->background_1.blue);
+                     if (optimize == 0) w = gamma_from_1[w];
+                     *(sp + 2) = w;
+                  }
+               }
+            }
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 4)
+               {
+                  png_byte a = *(sp + 3);
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)png_ptr->background.red;
+                     *(sp + 1) = (png_byte)png_ptr->background.green;
+                     *(sp + 2) = (png_byte)png_ptr->background.blue;
+                  }
+
+                  else if (a < 0xff)
+                  {
+                     png_composite(*sp, *sp, a, png_ptr->background.red);
+
+                     png_composite(*(sp + 1), *(sp + 1), a,
+                         png_ptr->background.green);
+
+                     png_composite(*(sp + 2), *(sp + 2), a,
+                         png_ptr->background.blue);
+                  }
+               }
+            }
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+#ifdef PNG_READ_GAMMA_SUPPORTED
+            if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                gamma_16_to_1 != NULL)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 8)
+               {
+                  png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                      << 8) + (png_uint_16)(*(sp + 7)));
+
+                  if (a == (png_uint_16)0xffff)
+                  {
+                     png_uint_16 v;
+
+                     v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+
+                  else if (a == 0)
+                  {
+                     /* Background is already in screen gamma */
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else
+                  {
+                     png_uint_16 v, w;
+
+                     v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                     png_composite_16(w, v, a, png_ptr->background_1.red);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+                     *sp = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(w & 0xff);
+
+                     v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                     png_composite_16(w, v, a, png_ptr->background_1.green);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+
+                     *(sp + 2) = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(w & 0xff);
+
+                     v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                     png_composite_16(w, v, a, png_ptr->background_1.blue);
+                     if (optimize == 0)
+                        w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
+                             8];
+
+                     *(sp + 4) = (png_byte)((w >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(w & 0xff);
+                  }
+               }
+            }
+
+            else
+#endif
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++, sp += 8)
+               {
+                  png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                      << 8) + (png_uint_16)(*(sp + 7)));
+
+                  if (a == 0)
+                  {
+                     *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
+                     *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
+                             & 0xff);
+                     *(sp + 3) = (png_byte)(png_ptr->background.green
+                             & 0xff);
+                     *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
+                             & 0xff);
+                     *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
+                  }
+
+                  else if (a < 0xffff)
+                  {
+                     png_uint_16 v;
+
+                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                         + *(sp + 3));
+                     png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                         + *(sp + 5));
+
+                     png_composite_16(v, r, a, png_ptr->background.red);
+                     *sp = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 1) = (png_byte)(v & 0xff);
+
+                     png_composite_16(v, g, a, png_ptr->background.green);
+                     *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 3) = (png_byte)(v & 0xff);
+
+                     png_composite_16(v, b, a, png_ptr->background.blue);
+                     *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                     *(sp + 5) = (png_byte)(v & 0xff);
+                  }
+               }
+            }
+         }
+         break;
+      }
+
+      default:
+         break;
    }
 }
 #endif /* READ_BACKGROUND || READ_ALPHA_MODE */
@@ -4365,195 +4362,130 @@
 
    png_debug(1, "in png_do_expand");
 
+   if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {
-      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+      unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
+
+      if (row_info->bit_depth < 8)
       {
-         unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
-
-         if (row_info->bit_depth < 8)
+         switch (row_info->bit_depth)
          {
-            switch (row_info->bit_depth)
+            case 1:
             {
-               case 1:
-               {
-                  gray = (gray & 0x01) * 0xff;
-                  sp = row + (png_size_t)((row_width - 1) >> 3);
-                  dp = row + (png_size_t)row_width - 1;
-                  shift = 7 - (int)((row_width + 7) & 0x07);
-                  for (i = 0; i < row_width; i++)
-                  {
-                     if ((*sp >> shift) & 0x01)
-                        *dp = 0xff;
-
-                     else
-                        *dp = 0;
-
-                     if (shift == 7)
-                     {
-                        shift = 0;
-                        sp--;
-                     }
-
-                     else
-                        shift++;
-
-                     dp--;
-                  }
-                  break;
-               }
-
-               case 2:
-               {
-                  gray = (gray & 0x03) * 0x55;
-                  sp = row + (png_size_t)((row_width - 1) >> 2);
-                  dp = row + (png_size_t)row_width - 1;
-                  shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
-                  for (i = 0; i < row_width; i++)
-                  {
-                     value = (*sp >> shift) & 0x03;
-                     *dp = (png_byte)(value | (value << 2) | (value << 4) |
-                        (value << 6));
-                     if (shift == 6)
-                     {
-                        shift = 0;
-                        sp--;
-                     }
-
-                     else
-                        shift += 2;
-
-                     dp--;
-                  }
-                  break;
-               }
-
-               case 4:
-               {
-                  gray = (gray & 0x0f) * 0x11;
-                  sp = row + (png_size_t)((row_width - 1) >> 1);
-                  dp = row + (png_size_t)row_width - 1;
-                  shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
-                  for (i = 0; i < row_width; i++)
-                  {
-                     value = (*sp >> shift) & 0x0f;
-                     *dp = (png_byte)(value | (value << 4));
-                     if (shift == 4)
-                     {
-                        shift = 0;
-                        sp--;
-                     }
-
-                     else
-                        shift = 4;
-
-                     dp--;
-                  }
-                  break;
-               }
-
-               default:
-                  break;
-            }
-
-            row_info->bit_depth = 8;
-            row_info->pixel_depth = 8;
-            row_info->rowbytes = row_width;
-         }
-
-         if (trans_color != NULL)
-         {
-            if (row_info->bit_depth == 8)
-            {
-               gray = gray & 0xff;
-               sp = row + (png_size_t)row_width - 1;
-               dp = row + ((png_size_t)row_width << 1) - 1;
-
+               gray = (gray & 0x01) * 0xff;
+               sp = row + (png_size_t)((row_width - 1) >> 3);
+               dp = row + (png_size_t)row_width - 1;
+               shift = 7 - (int)((row_width + 7) & 0x07);
                for (i = 0; i < row_width; i++)
                {
-                  if ((*sp & 0xffU) == gray)
-                     *dp-- = 0;
+                  if ((*sp >> shift) & 0x01)
+                     *dp = 0xff;
 
                   else
-                     *dp-- = 0xff;
+                     *dp = 0;
 
-                  *dp-- = *sp--;
-               }
-            }
-
-            else if (row_info->bit_depth == 16)
-            {
-               unsigned int gray_high = (gray >> 8) & 0xff;
-               unsigned int gray_low = gray & 0xff;
-               sp = row + row_info->rowbytes - 1;
-               dp = row + (row_info->rowbytes << 1) - 1;
-               for (i = 0; i < row_width; i++)
-               {
-                  if ((*(sp - 1) & 0xffU) == gray_high &&
-                      (*(sp) & 0xffU) == gray_low)
+                  if (shift == 7)
                   {
-                     *dp-- = 0;
-                     *dp-- = 0;
+                     shift = 0;
+                     sp--;
                   }
 
                   else
-                  {
-                     *dp-- = 0xff;
-                     *dp-- = 0xff;
-                  }
+                     shift++;
 
-                  *dp-- = *sp--;
-                  *dp-- = *sp--;
+                  dp--;
                }
+               break;
             }
 
-            row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
-            row_info->channels = 2;
-            row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
-            row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
-                row_width);
+            case 2:
+            {
+               gray = (gray & 0x03) * 0x55;
+               sp = row + (png_size_t)((row_width - 1) >> 2);
+               dp = row + (png_size_t)row_width - 1;
+               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x03;
+                  *dp = (png_byte)(value | (value << 2) | (value << 4) |
+                     (value << 6));
+                  if (shift == 6)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift += 2;
+
+                  dp--;
+               }
+               break;
+            }
+
+            case 4:
+            {
+               gray = (gray & 0x0f) * 0x11;
+               sp = row + (png_size_t)((row_width - 1) >> 1);
+               dp = row + (png_size_t)row_width - 1;
+               shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x0f;
+                  *dp = (png_byte)(value | (value << 4));
+                  if (shift == 4)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+
+                  else
+                     shift = 4;
+
+                  dp--;
+               }
+               break;
+            }
+
+            default:
+               break;
          }
+
+         row_info->bit_depth = 8;
+         row_info->pixel_depth = 8;
+         row_info->rowbytes = row_width;
       }
-      else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
-          trans_color != NULL)
+
+      if (trans_color != NULL)
       {
          if (row_info->bit_depth == 8)
          {
-            png_byte red = (png_byte)(trans_color->red & 0xff);
-            png_byte green = (png_byte)(trans_color->green & 0xff);
-            png_byte blue = (png_byte)(trans_color->blue & 0xff);
-            sp = row + (png_size_t)row_info->rowbytes - 1;
-            dp = row + ((png_size_t)row_width << 2) - 1;
+            gray = gray & 0xff;
+            sp = row + (png_size_t)row_width - 1;
+            dp = row + ((png_size_t)row_width << 1) - 1;
+
             for (i = 0; i < row_width; i++)
             {
-               if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
+               if ((*sp & 0xffU) == gray)
                   *dp-- = 0;
 
                else
                   *dp-- = 0xff;
 
                *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
             }
          }
+
          else if (row_info->bit_depth == 16)
          {
-            png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
-            png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
-            png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
-            png_byte red_low = (png_byte)(trans_color->red & 0xff);
-            png_byte green_low = (png_byte)(trans_color->green & 0xff);
-            png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
+            unsigned int gray_high = (gray >> 8) & 0xff;
+            unsigned int gray_low = gray & 0xff;
             sp = row + row_info->rowbytes - 1;
-            dp = row + ((png_size_t)row_width << 3) - 1;
+            dp = row + (row_info->rowbytes << 1) - 1;
             for (i = 0; i < row_width; i++)
             {
-               if (*(sp - 5) == red_high &&
-                   *(sp - 4) == red_low &&
-                   *(sp - 3) == green_high &&
-                   *(sp - 2) == green_low &&
-                   *(sp - 1) == blue_high &&
-                   *(sp    ) == blue_low)
+               if ((*(sp - 1) & 0xffU) == gray_high &&
+                   (*(sp) & 0xffU) == gray_low)
                {
                   *dp-- = 0;
                   *dp-- = 0;
@@ -4567,18 +4499,81 @@
 
                *dp-- = *sp--;
                *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
-               *dp-- = *sp--;
             }
          }
-         row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
-         row_info->channels = 4;
-         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
-         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+
+         row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+         row_info->channels = 2;
+         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+             row_width);
       }
    }
+   else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+       trans_color != NULL)
+   {
+      if (row_info->bit_depth == 8)
+      {
+         png_byte red = (png_byte)(trans_color->red & 0xff);
+         png_byte green = (png_byte)(trans_color->green & 0xff);
+         png_byte blue = (png_byte)(trans_color->blue & 0xff);
+         sp = row + (png_size_t)row_info->rowbytes - 1;
+         dp = row + ((png_size_t)row_width << 2) - 1;
+         for (i = 0; i < row_width; i++)
+         {
+            if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
+               *dp-- = 0;
+
+            else
+               *dp-- = 0xff;
+
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
+         png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
+         png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
+         png_byte red_low = (png_byte)(trans_color->red & 0xff);
+         png_byte green_low = (png_byte)(trans_color->green & 0xff);
+         png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
+         sp = row + row_info->rowbytes - 1;
+         dp = row + ((png_size_t)row_width << 3) - 1;
+         for (i = 0; i < row_width; i++)
+         {
+            if (*(sp - 5) == red_high &&
+                *(sp - 4) == red_low &&
+                *(sp - 3) == green_high &&
+                *(sp - 2) == green_low &&
+                *(sp - 1) == blue_high &&
+                *(sp    ) == blue_low)
+            {
+               *dp-- = 0;
+               *dp-- = 0;
+            }
+
+            else
+            {
+               *dp-- = 0xff;
+               *dp-- = 0xff;
+            }
+
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+            *dp-- = *sp--;
+         }
+      }
+      row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+      row_info->channels = 4;
+      row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
+   }
 }
 #endif