Imported from libpng-1.4.0beta20.tar
diff --git a/pngrtran.c b/pngrtran.c
index 4043948..0792c5b 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,9 +1,9 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * Last changed in libpng 1.4.0 May 15, 2007
+ * Last changed in libpng 1.4.0 [July 10, 2008]
  * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * Copyright (c) 1998-2008 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.)
  *
@@ -14,9 +14,8 @@
  */
 
 #include "png.h"
-#include "pngpriv.h"
-
 #if defined(PNG_READ_SUPPORTED)
+#include "pngpriv.h"
 
 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
 void PNGAPI
@@ -24,7 +23,7 @@
 {
    png_debug(1, "in png_set_crc_action\n");
    /* Tell libpng how we react to CRC errors in critical chunks */
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    switch (crit_action)
    {
       case PNG_CRC_NO_CHANGE:                        /* leave setting as is */
@@ -39,7 +38,8 @@
                            PNG_FLAG_CRC_CRITICAL_IGNORE;
          break;
       case PNG_CRC_WARN_DISCARD:    /* not a valid action for critical data */
-         png_warning(png_ptr, "Can't discard critical data on CRC error");
+         png_warning(png_ptr,
+            "Can't discard critical data on CRC error");
       case PNG_CRC_ERROR_QUIT:                                /* error/quit */
       case PNG_CRC_DEFAULT:
       default:
@@ -81,7 +81,7 @@
    int need_expand, double background_gamma)
 {
    png_debug(1, "in png_set_background\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
    {
       png_warning(png_ptr, "Application must supply a known background gamma");
@@ -89,21 +89,11 @@
    }
 
    png_ptr->transformations |= PNG_BACKGROUND;
-   png_memcpy(&(png_ptr->background), background_color, sizeof(png_color_16));
+   png_memcpy(&(png_ptr->background), background_color,
+      png_sizeof(png_color_16));
    png_ptr->background_gamma = (float)background_gamma;
    png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
    png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
-
-   /* Note:  if need_expand is set and color_type is either RGB or RGB_ALPHA
-    * (in which case need_expand is superfluous anyway), the background color
-    * might actually be gray yet not be flagged as such. This is not a problem
-    * for the current code, which uses PNG_BACKGROUND_IS_GRAY only to
-    * decide when to do the png_do_gray_to_rgb() transformation.
-    */
-   if ((need_expand && !(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) ||
-       (!need_expand && background_color->red == background_color->green &&
-        background_color->red == background_color->blue))
-      png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
 }
 #endif
 
@@ -113,7 +103,7 @@
 png_set_strip_16(png_structp png_ptr)
 {
    png_debug(1, "in png_set_strip_16\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    png_ptr->transformations |= PNG_16_TO_8;
 }
 #endif
@@ -123,7 +113,7 @@
 png_set_strip_alpha(png_structp png_ptr)
 {
    png_debug(1, "in png_set_strip_alpha\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
 }
 #endif
@@ -153,7 +143,7 @@
    int full_dither)
 {
    png_debug(1, "in png_set_dither\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    png_ptr->transformations |= PNG_DITHER;
 
    if (!full_dither)
@@ -161,7 +151,7 @@
       int i;
 
       png_ptr->dither_index = (png_bytep)png_malloc(png_ptr,
-         (png_size_t)(num_palette * sizeof(png_byte)));
+         (png_uint_32)(num_palette * png_sizeof(png_byte)));
       for (i = 0; i < num_palette; i++)
          png_ptr->dither_index[i] = (png_byte)i;
    }
@@ -177,7 +167,7 @@
 
          /* initialize an array to sort colors */
          png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr,
-            (png_size_t)(num_palette * sizeof(png_byte)));
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));
 
          /* initialize the dither_sort array */
          for (i = 0; i < num_palette; i++)
@@ -306,9 +296,9 @@
 
          /* initialize palette index arrays */
          png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
-            (png_size_t)(num_palette * sizeof(png_byte)));
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));
          png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
-            (png_size_t)(num_palette * sizeof(png_byte)));
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));
 
          /* initialize the sort array */
          for (i = 0; i < num_palette; i++)
@@ -317,11 +307,11 @@
             png_ptr->palette_to_index[i] = (png_byte)i;
          }
 
-         hash = (png_dsortpp)png_malloc(png_ptr,
-            (png_size_t)(769 * sizeof(png_dsortp)));
+         hash = (png_dsortpp)png_malloc(png_ptr, (png_uint_32)(769 *
+            png_sizeof(png_dsortp)));
          for (i = 0; i < 769; i++)
             hash[i] = NULL;
-/*         png_memset(hash, 0, 769 * sizeof(png_dsortp)); */
+/*         png_memset(hash, 0, 769 * png_sizeof(png_dsortp)); */
 
          num_new_palette = num_palette;
 
@@ -351,7 +341,7 @@
                   {
 
                      t = (png_dsortp)png_malloc_warn(png_ptr,
-                         sizeof(png_dsort));
+                         (png_uint_32)(png_sizeof(png_dsort)));
                      if (t == NULL)
                          break;
                      t->next = hash[d];
@@ -468,14 +458,16 @@
       int num_blue = (1 << PNG_DITHER_BLUE_BITS);
       png_size_t num_entries = ((png_size_t)1 << total_bits);
 
-      png_ptr->palette_lookup = (png_bytep)png_malloc(png_ptr,
-         num_entries * sizeof(png_byte));
+      png_ptr->palette_lookup = (png_bytep )png_malloc(png_ptr,
+         (png_uint_32)(num_entries * png_sizeof(png_byte)));
 
-      png_memset(png_ptr->palette_lookup, 0, num_entries * sizeof(png_byte));
+      png_memset(png_ptr->palette_lookup, 0, num_entries *
+         png_sizeof(png_byte));
 
-      distance = (png_bytep)png_malloc(png_ptr, num_entries * sizeof(png_byte));
+      distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
+         png_sizeof(png_byte)));
 
-      png_memset(distance, 0xff, num_entries * sizeof(png_byte));
+      png_memset(distance, 0xff, num_entries * png_sizeof(png_byte));
 
       for (i = 0; i < num_palette; i++)
       {
@@ -535,7 +527,7 @@
 png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 {
    png_debug(1, "in png_set_gamma\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) ||
        (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
        (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
@@ -554,8 +546,9 @@
 png_set_expand(png_structp png_ptr)
 {
    png_debug(1, "in png_set_expand\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
 
 /* GRR 19990627:  the following three functions currently are identical
@@ -580,8 +573,9 @@
 png_set_palette_to_rgb(png_structp png_ptr)
 {
    png_debug(1, "in png_set_palette_to_rgb\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
 
 /* Expand grayscale images of less than 8-bit depth to 8 bits. */
@@ -589,16 +583,20 @@
 png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
 {
    png_debug(1, "in png_set_expand_gray_1_2_4_to_8\n");
-   if(png_ptr == NULL) return;
-   png_ptr->transformations |= PNG_EXPAND_tRNS;
+   if (png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_EXPAND;
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
 
+
+
 /* Expand tRNS chunks to alpha channels. */
 void PNGAPI
 png_set_tRNS_to_alpha(png_structp png_ptr)
 {
-   png_debug(1, "in png_set_expand\n");
+   png_debug(1, "in png_set_tRNS_to_alpha\n");
    png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
 #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
 
@@ -608,6 +606,7 @@
 {
    png_debug(1, "in png_set_gray_to_rgb\n");
    png_ptr->transformations |= PNG_GRAY_TO_RGB;
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
 }
 #endif
 
@@ -623,7 +622,7 @@
 {
       int red_fixed = (int)((float)red*100000.0 + 0.5);
       int green_fixed = (int)((float)green*100000.0 + 0.5);
-      if(png_ptr == NULL) return;
+      if (png_ptr == NULL) return;
       png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
 }
 #endif
@@ -633,7 +632,7 @@
    png_fixed_point red, png_fixed_point green)
 {
    png_debug(1, "in png_set_rgb_to_gray\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
    switch(error_action)
    {
       case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
@@ -647,18 +646,19 @@
       png_ptr->transformations |= PNG_EXPAND;
 #else
    {
-      png_warning(png_ptr, "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
+      png_warning(png_ptr,
+        "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
       png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
    }
 #endif
    {
       png_uint_16 red_int, green_int;
-      if(red < 0 || green < 0)
+      if (red < 0 || green < 0)
       {
          red_int   =  6968; /* .212671 * 32768 + .5 */
          green_int = 23434; /* .715160 * 32768 + .5 */
       }
-      else if(red + green < 100000L)
+      else if (red + green < 100000L)
       {
         red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
         green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
@@ -671,7 +671,8 @@
       }
       png_ptr->rgb_to_gray_red_coeff   = red_int;
       png_ptr->rgb_to_gray_green_coeff = green_int;
-      png_ptr->rgb_to_gray_blue_coeff  = (png_uint_16)(32768-red_int-green_int);
+      png_ptr->rgb_to_gray_blue_coeff  = 
+         (png_uint_16)(32768 - red_int - green_int);
    }
 }
 #endif
@@ -684,13 +685,13 @@
    read_user_transform_fn)
 {
    png_debug(1, "in png_set_read_user_transform_fn\n");
-   if(png_ptr == NULL) return;
+   if (png_ptr == NULL) return;
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
    png_ptr->transformations |= PNG_USER_TRANSFORM;
    png_ptr->read_user_transform_fn = read_user_transform_fn;
 #endif
 #ifdef PNG_LEGACY_SUPPORTED
-   if(read_user_transform_fn)
+   if (read_user_transform_fn)
       png_warning(png_ptr,
         "This version of libpng does not support user transforms");
 #endif
@@ -705,7 +706,7 @@
 {
    png_debug(1, "in png_init_read_transformations\n");
 #if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if(png_ptr != NULL)
+   if (png_ptr != NULL)
 #endif
   {
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \
@@ -714,6 +715,32 @@
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+   /* Detect gray background and attempt to enable optimization
+    * for gray --> RGB case */
+   /* Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+    * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+    * background color might actually be gray yet not be flagged as such.
+    * This is not a problem for the current code, which uses
+    * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+    * png_do_gray_to_rgb() transformation.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+       !(color_type & PNG_COLOR_MASK_COLOR))
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+   } else if ((png_ptr->transformations & PNG_BACKGROUND) &&
+              !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+              (png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+              png_ptr->background.red == png_ptr->background.green &&
+              png_ptr->background.red == png_ptr->background.blue)
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+          png_ptr->background.gray = png_ptr->background.red;
+   }
+#endif
+
    if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
        (png_ptr->transformations & PNG_EXPAND))
    {
@@ -780,7 +807,7 @@
            {
            /* invert the alpha channel (in tRNS) unless the pixels are
               going to be expanded, in which case leave it for later */
-              int i,istop;
+              int i, istop;
               istop=(int)png_ptr->num_trans;
               for (i=0; i<istop; i++)
                  png_ptr->trans[i] = (png_byte)(255 - png_ptr->trans[i]);
@@ -801,7 +828,7 @@
        && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
          < PNG_GAMMA_THRESHOLD))
    {
-    int i,k;
+    int i, k;
     k=0;
     for (i=0; i<png_ptr->num_trans; i++)
     {
@@ -809,7 +836,7 @@
         k=1; /* partial transparency is present */
     }
     if (k == 0)
-      png_ptr->transformations &= (~PNG_GAMMA);
+      png_ptr->transformations &= ~PNG_GAMMA;
    }
 
    if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
@@ -916,6 +943,14 @@
                   palette[i].blue = png_ptr->gamma_table[palette[i].blue];
                }
             }
+	    /* Prevent the transformations being done again, and make sure
+	     * that the now spurious alpha channel is stripped - the code
+	     * has just reduced background composition and gamma correction
+	     * to a simple alpha channel strip.
+	     */
+	    png_ptr->transformations &= ~PNG_BACKGROUND;
+	    png_ptr->transformations &= ~PNG_GAMMA;
+	    png_ptr->transformations |= PNG_STRIP_ALPHA;
          }
          /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
          else
@@ -990,6 +1025,9 @@
             palette[i].green = png_ptr->gamma_table[palette[i].green];
             palette[i].blue = png_ptr->gamma_table[palette[i].blue];
          }
+
+	 /* Done the gamma correction. */
+	 png_ptr->transformations &= ~PNG_GAMMA;
       }
    }
 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
@@ -1027,6 +1065,10 @@
                png_ptr->trans[i], back.blue);
          }
       }
+
+      /* Handled alpha, still need to strip the channel. */
+      png_ptr->transformations &= ~PNG_BACKGROUND;
+      png_ptr->transformations |= PNG_STRIP_ALPHA;
    }
 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
 
@@ -1057,7 +1099,7 @@
  }
 #if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
  && !defined(PNG_READ_BACKGROUND_SUPPORTED)
-   if(png_ptr)
+   if (png_ptr)
       return;
 #endif
 }
@@ -1075,7 +1117,8 @@
    {
       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
-         if (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND_tRNS))
+         if (png_ptr->num_trans &&
+              (png_ptr->transformations & PNG_EXPAND_tRNS))
             info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
          else
             info_ptr->color_type = PNG_COLOR_TYPE_RGB;
@@ -1088,8 +1131,10 @@
          {
             if (png_ptr->transformations & PNG_EXPAND_tRNS)
               info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+#if 0 /* Removed from libpng-1.2.27 */
             else
               info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
+#endif
          }
          if (info_ptr->bit_depth < 8)
             info_ptr->bit_depth = 8;
@@ -1181,11 +1226,11 @@
 
 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
 defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
-   if(png_ptr->transformations & PNG_USER_TRANSFORM)
+   if (png_ptr->transformations & PNG_USER_TRANSFORM)
      {
-       if(info_ptr->bit_depth < png_ptr->user_transform_depth)
+       if (info_ptr->bit_depth < png_ptr->user_transform_depth)
          info_ptr->bit_depth = png_ptr->user_transform_depth;
-       if(info_ptr->channels < png_ptr->user_transform_channels)
+       if (info_ptr->channels < png_ptr->user_transform_channels)
          info_ptr->channels = png_ptr->user_transform_channels;
      }
 #endif
@@ -1193,10 +1238,10 @@
    info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
       info_ptr->bit_depth);
 
-   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,info_ptr->width);
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
 
 #if !defined(PNG_READ_EXPAND_SUPPORTED)
-   if(png_ptr)
+   if (png_ptr)
       return;
 #endif
 }
@@ -1209,19 +1254,29 @@
 png_do_read_transformations(png_structp png_ptr)
 {
    png_debug(1, "in png_do_read_transformations\n");
-#if !defined(PNG_USELESS_TESTS_SUPPORTED)
    if (png_ptr->row_buf == NULL)
    {
-#ifndef PNG_NO_STDIO
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
       char msg[50];
 
-      png_sprintf(msg, "NULL row buffer for row %lu, pass %d",
-         (unsigned long) png_ptr->row_number, png_ptr->pass);
+      png_snprintf2(msg, 50,
+         "NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number,
+         png_ptr->pass);
       png_error(png_ptr, msg);
 #else
       png_error(png_ptr, "NULL row buffer");
 #endif
    }
+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+      /* Application has failed to call either png_read_start_image()
+       * or png_read_update_info() after setting transforms that expand
+       * pixels.  This check added to libpng-1.2.19 */
+#if (PNG_WARN_UNINITIALIZED_ROW==1)
+      png_error(png_ptr, "Uninitialized row");
+#else
+      png_warning(png_ptr, "Uninitialized row");
+#endif
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED)
@@ -1234,7 +1289,8 @@
       }
       else
       {
-         if (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND_tRNS))
+         if (png_ptr->num_trans &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS))
             png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
                &(png_ptr->trans_values));
          else
@@ -1255,12 +1311,14 @@
    {
       int rgb_error =
          png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1);
-      if(rgb_error)
+      if (rgb_error)
       {
          png_ptr->rgb_to_gray_status=1;
-         if(png_ptr->transformations == PNG_RGB_TO_GRAY_WARN)
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 
+             PNG_RGB_TO_GRAY_WARN)
             png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
-         if(png_ptr->transformations == PNG_RGB_TO_GRAY_ERR)
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_ERR)
             png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
       }
    }
@@ -1343,7 +1401,7 @@
    {
       png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1,
          png_ptr->palette_lookup, png_ptr->dither_index);
-      if(png_ptr->row_info.rowbytes == (png_uint_32)0)
+      if (png_ptr->row_info.rowbytes == (png_uint_32)0)
          png_error(png_ptr, "png_do_dither returned rowbytes=0");
    }
 #endif
@@ -1405,7 +1463,7 @@
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
    if (png_ptr->transformations & PNG_USER_TRANSFORM)
     {
-      if(png_ptr->read_user_transform_fn != NULL)
+      if (png_ptr->read_user_transform_fn != NULL)
         (*(png_ptr->read_user_transform_fn)) /* user read transform function */
           (png_ptr,                    /* png_ptr */
            &(png_ptr->row_info),       /* row_info:     */
@@ -1417,9 +1475,9 @@
              /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
            png_ptr->row_buf + 1);      /* start of pixel data for row */
 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
-      if(png_ptr->user_transform_depth)
+      if (png_ptr->user_transform_depth)
          png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
-      if(png_ptr->user_transform_channels)
+      if (png_ptr->user_transform_channels)
          png_ptr->row_info.channels = png_ptr->user_transform_channels;
 #endif
       png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
@@ -1896,7 +1954,7 @@
 #endif
        row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {
-      if(row_info->bit_depth == 8)
+      if (row_info->bit_depth == 8)
       {
          /* This changes the data from G to GX */
          if (flags & PNG_FLAG_FILLER_AFTER)
@@ -1928,7 +1986,7 @@
             row_info->rowbytes = row_width * 2;
          }
       }
-      else if(row_info->bit_depth == 16)
+      else if (row_info->bit_depth == 16)
       {
          /* This changes the data from GG to GGXX */
          if (flags & PNG_FLAG_FILLER_AFTER)
@@ -1968,7 +2026,7 @@
    } /* COLOR_TYPE == GRAY */
    else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
    {
-      if(row_info->bit_depth == 8)
+      if (row_info->bit_depth == 8)
       {
          /* This changes the data from RGB to RGBX */
          if (flags & PNG_FLAG_FILLER_AFTER)
@@ -2004,7 +2062,7 @@
             row_info->rowbytes = row_width * 4;
          }
       }
-      else if(row_info->bit_depth == 16)
+      else if (row_info->bit_depth == 16)
       {
          /* This changes the data from RRGGBB to RRGGBBXX */
          if (flags & PNG_FLAG_FILLER_AFTER)
@@ -2131,7 +2189,7 @@
       row_info->color_type |= PNG_COLOR_MASK_COLOR;
       row_info->pixel_depth = (png_byte)(row_info->channels *
          row_info->bit_depth);
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
    }
 }
 #endif
@@ -2139,8 +2197,11 @@
 #if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
 /* reduce RGB files to grayscale, with or without alpha
  * using the equation given in Poynton's ColorFAQ at
- * <http://www.inforamp.net/~poynton/>
+ * <http://www.inforamp.net/~poynton/>  (THIS LINK IS DEAD June 2008)
  * Copyright (c) 1998-01-04 Charles Poynton poynton at inforamp.net
+ * New links:
+ * <http://www.poynton.com/notes/colour_and_gamma/>
+ * Copyright (c) 2006-11-28 Charles Poynton poynton at poynton.com
  *
  *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
  *
@@ -2191,14 +2252,14 @@
                   png_byte red   = png_ptr->gamma_to_1[*(sp++)];
                   png_byte green = png_ptr->gamma_to_1[*(sp++)];
                   png_byte blue  = png_ptr->gamma_to_1[*(sp++)];
-                  if(red != green || red != blue)
+                  if (red != green || red != blue)
                   {
                      rgb_error |= 1;
                      *(dp++) = png_ptr->gamma_from_1[
-                       (rc*red+gc*green+bc*blue)>>15];
+                       (rc*red + gc*green + bc*blue)>>15];
                   }
                   else
-                     *(dp++) = *(sp-1);
+                     *(dp++) = *(sp - 1);
                }
             }
             else
@@ -2211,13 +2272,13 @@
                   png_byte red   = *(sp++);
                   png_byte green = *(sp++);
                   png_byte blue  = *(sp++);
-                  if(red != green || red != blue)
+                  if (red != green || red != blue)
                   {
                      rgb_error |= 1;
-                     *(dp++) = (png_byte)((rc*red+gc*green+bc*blue)>>15);
+                     *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
                   }
                   else
-                     *(dp++) = *(sp-1);
+                     *(dp++) = *(sp - 1);
                }
             }
          }
@@ -2238,7 +2299,7 @@
                   green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
                   blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
 
-                  if(red == green && red == blue)
+                  if (red == green && red == blue)
                      w = red;
                   else
                   {
@@ -2272,7 +2333,7 @@
                   green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
                   blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
 
-                  if(red != green || red != blue)
+                  if (red != green || red != blue)
                      rgb_error |= 1;
                   gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
                   *(dp++) = (png_byte)((gray16>>8) & 0xff);
@@ -2295,7 +2356,7 @@
                   png_byte red   = png_ptr->gamma_to_1[*(sp++)];
                   png_byte green = png_ptr->gamma_to_1[*(sp++)];
                   png_byte blue  = png_ptr->gamma_to_1[*(sp++)];
-                  if(red != green || red != blue)
+                  if (red != green || red != blue)
                      rgb_error |= 1;
                   *(dp++) =  png_ptr->gamma_from_1
                              [(rc*red + gc*green + bc*blue)>>15];
@@ -2312,7 +2373,7 @@
                   png_byte red   = *(sp++);
                   png_byte green = *(sp++);
                   png_byte blue  = *(sp++);
-                  if(red != green || red != blue)
+                  if (red != green || red != blue)
                      rgb_error |= 1;
                   *(dp++) =  (png_byte)((rc*red + gc*green + bc*blue)>>15);
                   *(dp++) = *(sp++);  /* alpha */
@@ -2335,7 +2396,7 @@
                   green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
                   blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
 
-                  if(red == green && red == blue)
+                  if (red == green && red == blue)
                      w = red;
                   else
                   {
@@ -2369,7 +2430,7 @@
                   red   = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
                   green = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
                   blue  = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
-                  if(red != green || red != blue)
+                  if (red != green || red != blue)
                      rgb_error |= 1;
                   gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
                   *(dp++) = (png_byte)((gray16>>8) & 0xff);
@@ -2384,7 +2445,7 @@
       row_info->color_type &= ~PNG_COLOR_MASK_COLOR;
       row_info->pixel_depth = (png_byte)(row_info->channels *
          row_info->bit_depth);
-      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
    }
    return rgb_error;
 }
@@ -3302,7 +3363,7 @@
          row_info->channels--;
          row_info->pixel_depth = (png_byte)(row_info->channels *
             row_info->bit_depth);
-         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
       }
    }
 }
@@ -3664,7 +3725,7 @@
             {
                case 1:
                {
-                  gray = (png_uint_16)(gray*0xff);
+                  gray = (png_uint_16)((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);
@@ -3688,7 +3749,7 @@
                }
                case 2:
                {
-                  gray = (png_uint_16)(gray*0x55);
+                  gray = (png_uint_16)((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);
@@ -3711,7 +3772,7 @@
                }
                case 4:
                {
-                  gray = (png_uint_16)(gray*0x11);
+                  gray = (png_uint_16)((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);
@@ -3741,6 +3802,7 @@
          {
             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;
                for (i = 0; i < row_width; i++)
@@ -3754,12 +3816,13 @@
             }
             else if (row_info->bit_depth == 16)
             {
+               png_byte gray_high = (gray >> 8) & 0xff;
+               png_byte 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 (((png_uint_16)*(sp) |
-                     ((png_uint_16)*(sp - 1) << 8)) == gray)
+                  if (*(sp - 1) == gray_high && *(sp) == gray_low) 
                   {
                      *dp-- = 0;
                      *dp-- = 0;
@@ -3784,13 +3847,14 @@
       {
          if (row_info->bit_depth == 8)
          {
+            png_byte red = trans_value->red & 0xff;
+            png_byte green = trans_value->green & 0xff;
+            png_byte blue = trans_value->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) == trans_value->red &&
-                  *(sp - 1) == trans_value->green &&
-                  *(sp - 0) == trans_value->blue)
+               if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
                   *dp-- = 0;
                else
                   *dp-- = 0xff;
@@ -3801,16 +3865,22 @@
          }
          else if (row_info->bit_depth == 16)
          {
+            png_byte red_high = (trans_value->red >> 8) & 0xff;
+            png_byte green_high = (trans_value->green >> 8) & 0xff;
+            png_byte blue_high = (trans_value->blue >> 8) & 0xff;
+            png_byte red_low = trans_value->red & 0xff;
+            png_byte green_low = trans_value->green & 0xff;
+            png_byte blue_low = trans_value->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 ((((png_uint_16)*(sp - 4) |
-                  ((png_uint_16)*(sp - 5) << 8)) == trans_value->red) &&
-                  (((png_uint_16)*(sp - 2) |
-                  ((png_uint_16)*(sp - 3) << 8)) == trans_value->green) &&
-                  (((png_uint_16)*(sp - 0) |
-                  ((png_uint_16)*(sp - 1) << 8)) == trans_value->blue))
+               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;
@@ -3831,7 +3901,7 @@
          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->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
       }
    }
 }
@@ -3884,7 +3954,7 @@
          row_info->color_type = PNG_COLOR_TYPE_PALETTE;
          row_info->channels = 1;
          row_info->pixel_depth = row_info->bit_depth;
-         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
       }
       else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
          palette_lookup != NULL && row_info->bit_depth == 8)
@@ -3913,7 +3983,7 @@
          row_info->color_type = PNG_COLOR_TYPE_PALETTE;
          row_info->channels = 1;
          row_info->pixel_depth = row_info->bit_depth;
-         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
       }
       else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
          dither_lookup && row_info->bit_depth == 8)
@@ -3930,8 +4000,8 @@
 
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 #if defined(PNG_READ_GAMMA_SUPPORTED)
-static int png_gamma_shift[] =
-   {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0, 0x000};
+static PNG_CONST int png_gamma_shift[] =
+   {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0, 0x00};
 
 /* We build the 8- or 16-bit gamma tables here.  Note that for 16-bit
  * tables, we don't make a full table if we are reducing to 8-bit in
@@ -3953,7 +4023,8 @@
      else
         g = 1.0;
 
-     png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr, 256);
+     png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr,
+        (png_uint_32)256);
 
      for (i = 0; i < 256; i++)
      {
@@ -3968,7 +4039,8 @@
 
         g = 1.0 / (png_ptr->gamma);
 
-        png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr, 256);
+        png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr,
+           (png_uint_32)256);
 
         for (i = 0; i < 256; i++)
         {
@@ -3977,9 +4049,10 @@
         }
 
 
-        png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr, 256);
+        png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr,
+           (png_uint_32)256);
 
-        if(png_ptr->screen_gamma > 0.000001)
+        if (png_ptr->screen_gamma > 0.000001)
            g = 1.0 / png_ptr->screen_gamma;
         else
            g = png_ptr->gamma;   /* probably doing rgb_to_gray */
@@ -4039,7 +4112,7 @@
         g = 1.0;
 
      png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr,
-        (png_size_t)(num * sizeof(png_uint_16p)));
+        (png_uint_32)(num * png_sizeof(png_uint_16p)));
 
      if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
      {
@@ -4049,7 +4122,7 @@
         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
-              256 * sizeof(png_uint_16));
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
         }
 
         g = 1.0 / g;
@@ -4079,7 +4152,7 @@
         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
-              256 * sizeof(png_uint_16));
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
 
            ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4);
            for (j = 0; j < 256; j++)
@@ -4099,12 +4172,12 @@
         g = 1.0 / (png_ptr->gamma);
 
         png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr,
-           (png_size_t)(num * sizeof(png_uint_16p)));
+           (png_uint_32)(num * png_sizeof(png_uint_16p )));
 
         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr,
-              256 * sizeof(png_uint_16));
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
 
            ig = (((png_uint_32)i *
               (png_uint_32)png_gamma_shift[shift]) >> 4);
@@ -4116,18 +4189,18 @@
            }
         }
 
-        if(png_ptr->screen_gamma > 0.000001)
+        if (png_ptr->screen_gamma > 0.000001)
            g = 1.0 / png_ptr->screen_gamma;
         else
            g = png_ptr->gamma;   /* probably doing rgb_to_gray */
 
         png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr,
-           (png_size_t)(num * sizeof(png_uint_16p)));
+           (png_uint_32)(num * png_sizeof(png_uint_16p)));
 
         for (i = 0; i < num; i++)
         {
            png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_malloc(png_ptr,
-              256 * sizeof(png_uint_16));
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
 
            ig = (((png_uint_32)i *
               (png_uint_32)png_gamma_shift[shift]) >> 4);
@@ -4192,11 +4265,11 @@
 
          for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
          {
-            png_uint_32 s0   = (*(rp  ) << 8) | *(rp+1);
-            png_uint_32 s1   = (*(rp+2) << 8) | *(rp+3);
-            png_uint_32 s2   = (*(rp+4) << 8) | *(rp+5);
-            png_uint_32 red  = (png_uint_32)((s0+s1+65536L) & 0xffffL);
-            png_uint_32 blue = (png_uint_32)((s2+s1+65536L) & 0xffffL);
+            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (png_uint_32)((s0 + s1 + 65536L) & 0xffffL);
+            png_uint_32 blue = (png_uint_32)((s2 + s1 + 65536L) & 0xffffL);
             *(rp  ) = (png_byte)((red >> 8) & 0xff);
             *(rp+1) = (png_byte)(red & 0xff);
             *(rp+4) = (png_byte)((blue >> 8) & 0xff);