fife-parpg: ext/libpng-1.2.29/pngrtran.c comparison

comparison ext/libpng-1.2.29/pngrtran.c @ 89:fa33cda75471

* Reverting back to 2543 as requested by sleek

author	mvbarracuda@33b003aa-7bff-0310-803a-e67f0ece8222
date	Sat, 19 Jul 2008 11:38:52 +0000
parents	4a0efb7baf70
children

comparison

equal deleted inserted replaced

-:1c2842ebe393
+:fa33cda75471
+/* pngrtran.c - transforms the data in a row for PNG readers
+*
+* Last changed in libpng 1.2.27 [April 29, 2008]
+* For conditions of distribution and use, see copyright notice in png.h
+* 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.)
+*
+* This file contains functions optionally called by an application
+* in order to tell libpng how to handle data when reading a PNG.
+* Transformations that are used in both reading and writing are
+* in pngtrans.c.
+*/
+#define PNG_INTERNAL
+#include "png.h"
+#if defined(PNG_READ_SUPPORTED)
+/* Set the action on getting a CRC error for an ancillary or critical chunk. */
+void PNGAPI
+png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
+{
+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;
+switch (crit_action)
+{
+case PNG_CRC_NO_CHANGE:                        /* leave setting as is */
+break;
+case PNG_CRC_WARN_USE:                               /* warn/use data */
+png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
+break;
+case PNG_CRC_QUIET_USE:                             /* quiet/use data */
+png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
+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.");
+case PNG_CRC_ERROR_QUIT:                                /* error/quit */
+case PNG_CRC_DEFAULT:
+default:
+png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+break;
+}
+switch (ancil_action)
+{
+case PNG_CRC_NO_CHANGE:                       /* leave setting as is */
+break;
+case PNG_CRC_WARN_USE:                              /* warn/use data */
+png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
+break;
+case PNG_CRC_QUIET_USE:                            /* quiet/use data */
+png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
+PNG_FLAG_CRC_ANCILLARY_NOWARN;
+break;
+case PNG_CRC_ERROR_QUIT:                               /* error/quit */
+png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
+break;
+case PNG_CRC_WARN_DISCARD:                      /* warn/discard data */
+case PNG_CRC_DEFAULT:
+default:
+png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+break;
+}
+}
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+defined(PNG_FLOATING_POINT_SUPPORTED)
+/* handle alpha and tRNS via a background color */
+void PNGAPI
+png_set_background(png_structp png_ptr,
+png_color_16p background_color, int background_gamma_code,
+int need_expand, double background_gamma)
+{
+png_debug(1, "in png_set_background\n");
+if(png_ptr == NULL) return;
+if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
+{
+png_warning(png_ptr, "Application must supply a known background gamma");
+return;
+}
+png_ptr->transformations |= PNG_BACKGROUND;
+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);
+}
+#endif
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+/* strip 16 bit depth files to 8 bit depth */
+void PNGAPI
+png_set_strip_16(png_structp png_ptr)
+{
+png_debug(1, "in png_set_strip_16\n");
+if(png_ptr == NULL) return;
+png_ptr->transformations |= PNG_16_TO_8;
+}
+#endif
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_strip_alpha(png_structp png_ptr)
+{
+png_debug(1, "in png_set_strip_alpha\n");
+if(png_ptr == NULL) return;
+png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
+}
+#endif
+#if defined(PNG_READ_DITHER_SUPPORTED)
+/* Dither file to 8 bit.  Supply a palette, the current number
+* of elements in the palette, the maximum number of elements
+* allowed, and a histogram if possible.  If the current number
+* of colors is greater then the maximum number, the palette will be
+* modified to fit in the maximum number.  "full_dither" indicates
+* whether we need a dithering cube set up for RGB images, or if we
+* simply are reducing the number of colors in a paletted image.
+*/
+typedef struct png_dsort_struct
+{
+struct png_dsort_struct FAR * next;
+png_byte left;
+png_byte right;
+} png_dsort;
+typedef png_dsort FAR *       png_dsortp;
+typedef png_dsort FAR * FAR * png_dsortpp;
+void PNGAPI
+png_set_dither(png_structp png_ptr, png_colorp palette,
+int num_palette, int maximum_colors, png_uint_16p histogram,
+int full_dither)
+{
+png_debug(1, "in png_set_dither\n");
+if(png_ptr == NULL) return;
+png_ptr->transformations |= PNG_DITHER;
+if (!full_dither)
+{
+int i;
+png_ptr->dither_index = (png_bytep)png_malloc(png_ptr,
+(png_uint_32)(num_palette * png_sizeof (png_byte)));
+for (i = 0; i < num_palette; i++)
+png_ptr->dither_index[i] = (png_byte)i;
+}
+if (num_palette > maximum_colors)
+{
+if (histogram != NULL)
+{
+/* This is easy enough, just throw out the least used colors.
+Perhaps not the best solution, but good enough. */
+int i;
+/* initialize an array to sort colors */
+png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr,
+(png_uint_32)(num_palette * png_sizeof (png_byte)));
+/* initialize the dither_sort array */
+for (i = 0; i < num_palette; i++)
+png_ptr->dither_sort[i] = (png_byte)i;
+/* Find the least used palette entries by starting a
+bubble sort, and running it until we have sorted
+out enough colors.  Note that we don't care about
+sorting all the colors, just finding which are
+least used. */
+for (i = num_palette - 1; i >= maximum_colors; i--)
+{
+int done; /* to stop early if the list is pre-sorted */
+int j;
+done = 1;
+for (j = 0; j < i; j++)
+{
+if (histogram[png_ptr->dither_sort[j]]
+< histogram[png_ptr->dither_sort[j + 1]])
+{
+png_byte t;
+t = png_ptr->dither_sort[j];
+png_ptr->dither_sort[j] = png_ptr->dither_sort[j + 1];
+png_ptr->dither_sort[j + 1] = t;
+done = 0;
+}
+}
+if (done)
+break;
+}
+/* swap the palette around, and set up a table, if necessary */
+if (full_dither)
+{
+int j = num_palette;
+/* put all the useful colors within the max, but don't
+move the others */
+for (i = 0; i < maximum_colors; i++)
+{
+if ((int)png_ptr->dither_sort[i] >= maximum_colors)
+{
+do
+j--;
+while ((int)png_ptr->dither_sort[j] >= maximum_colors);
+palette[i] = palette[j];
+}
+}
+}
+else
+{
+int j = num_palette;
+/* move all the used colors inside the max limit, and
+develop a translation table */
+for (i = 0; i < maximum_colors; i++)
+{
+/* only move the colors we need to */
+if ((int)png_ptr->dither_sort[i] >= maximum_colors)
+{
+png_color tmp_color;
+do
+j--;
+while ((int)png_ptr->dither_sort[j] >= maximum_colors);
+tmp_color = palette[j];
+palette[j] = palette[i];
+palette[i] = tmp_color;
+/* indicate where the color went */
+png_ptr->dither_index[j] = (png_byte)i;
+png_ptr->dither_index[i] = (png_byte)j;
+}
+}
+/* find closest color for those colors we are not using */
+for (i = 0; i < num_palette; i++)
+{
+if ((int)png_ptr->dither_index[i] >= maximum_colors)
+{
+int min_d, k, min_k, d_index;
+/* find the closest color to one we threw out */
+d_index = png_ptr->dither_index[i];
+min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
+for (k = 1, min_k = 0; k < maximum_colors; k++)
+{
+int d;
+d = PNG_COLOR_DIST(palette[d_index], palette[k]);
+if (d < min_d)
+{
+min_d = d;
+min_k = k;
+}
+}
+/* point to closest color */
+png_ptr->dither_index[i] = (png_byte)min_k;
+}
+}
+}
+png_free(png_ptr, png_ptr->dither_sort);
+png_ptr->dither_sort=NULL;
+}
+else
+{
+/* This is much harder to do simply (and quickly).  Perhaps
+we need to go through a median cut routine, but those
+don't always behave themselves with only a few colors
+as input.  So we will just find the closest two colors,
+and throw out one of them (chosen somewhat randomly).
+[We don't understand this at all, so if someone wants to
+work on improving it, be our guest - AED, GRP]
+*/
+int i;
+int max_d;
+int num_new_palette;
+png_dsortp t;
+png_dsortpp hash;
+t=NULL;
+/* initialize palette index arrays */
+png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
+(png_uint_32)(num_palette * png_sizeof (png_byte)));
+png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
+(png_uint_32)(num_palette * png_sizeof (png_byte)));
+/* initialize the sort array */
+for (i = 0; i < num_palette; i++)
+{
+png_ptr->index_to_palette[i] = (png_byte)i;
+png_ptr->palette_to_index[i] = (png_byte)i;
+}
+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 * png_sizeof (png_dsortp)); */
+num_new_palette = num_palette;
+/* initial wild guess at how far apart the farthest pixel
+pair we will be eliminating will be.  Larger
+numbers mean more areas will be allocated, Smaller
+numbers run the risk of not saving enough data, and
+having to do this all over again.
+I have not done extensive checking on this number.
+*/
+max_d = 96;
+while (num_new_palette > maximum_colors)
+{
+for (i = 0; i < num_new_palette - 1; i++)
+{
+int j;
+for (j = i + 1; j < num_new_palette; j++)
+{
+int d;
+d = PNG_COLOR_DIST(palette[i], palette[j]);
+if (d <= max_d)
+{
+t = (png_dsortp)png_malloc_warn(png_ptr,
+(png_uint_32)(png_sizeof(png_dsort)));
+if (t == NULL)
+break;
+t->next = hash[d];
+t->left = (png_byte)i;
+t->right = (png_byte)j;
+hash[d] = t;
+}
+}
+if (t == NULL)
+break;
+}
+if (t != NULL)
+for (i = 0; i <= max_d; i++)
+{
+if (hash[i] != NULL)
+{
+png_dsortp p;
+for (p = hash[i]; p; p = p->next)
+{
+if ((int)png_ptr->index_to_palette[p->left]
+< num_new_palette &&
+(int)png_ptr->index_to_palette[p->right]
+< num_new_palette)
+{
+int j, next_j;
+if (num_new_palette & 0x01)
+{
+j = p->left;
+next_j = p->right;
+}
+else
+{
+j = p->right;
+next_j = p->left;
+}
+num_new_palette--;
+palette[png_ptr->index_to_palette[j]]
+= palette[num_new_palette];
+if (!full_dither)
+{
+int k;
+for (k = 0; k < num_palette; k++)
+{
+if (png_ptr->dither_index[k] ==
+png_ptr->index_to_palette[j])
+png_ptr->dither_index[k] =
+png_ptr->index_to_palette[next_j];
+if ((int)png_ptr->dither_index[k] ==
+num_new_palette)
+png_ptr->dither_index[k] =
+png_ptr->index_to_palette[j];
+}
+}
+png_ptr->index_to_palette[png_ptr->palette_to_index
+[num_new_palette]] = png_ptr->index_to_palette[j];
+png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
+= png_ptr->palette_to_index[num_new_palette];
+png_ptr->index_to_palette[j] = (png_byte)num_new_palette;
+png_ptr->palette_to_index[num_new_palette] = (png_byte)j;
+}
+if (num_new_palette <= maximum_colors)
+break;
+}
+if (num_new_palette <= maximum_colors)
+break;
+}
+}
+for (i = 0; i < 769; i++)
+{
+if (hash[i] != NULL)
+{
+png_dsortp p = hash[i];
+while (p)
+{
+t = p->next;
+png_free(png_ptr, p);
+p = t;
+}
+}
+hash[i] = 0;
+}
+max_d += 96;
+}
+png_free(png_ptr, hash);
+png_free(png_ptr, png_ptr->palette_to_index);
+png_free(png_ptr, png_ptr->index_to_palette);
+png_ptr->palette_to_index=NULL;
+png_ptr->index_to_palette=NULL;
+}
+num_palette = maximum_colors;
+}
+if (png_ptr->palette == NULL)
+{
+png_ptr->palette = palette;
+}
+png_ptr->num_palette = (png_uint_16)num_palette;
+if (full_dither)
+{
+int i;
+png_bytep distance;
+int total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS +
+PNG_DITHER_BLUE_BITS;
+int num_red = (1 << PNG_DITHER_RED_BITS);
+int num_green = (1 << PNG_DITHER_GREEN_BITS);
+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,
+(png_uint_32)(num_entries * png_sizeof (png_byte)));
+png_memset(png_ptr->palette_lookup, 0, num_entries *
+png_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 * png_sizeof(png_byte));
+for (i = 0; i < num_palette; i++)
+{
+int ir, ig, ib;
+int r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS));
+int g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS));
+int b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS));
+for (ir = 0; ir < num_red; ir++)
+{
+/* int dr = abs(ir - r); */
+int dr = ((ir > r) ? ir - r : r - ir);
+int index_r = (ir << (PNG_DITHER_BLUE_BITS + PNG_DITHER_GREEN_BITS));
+for (ig = 0; ig < num_green; ig++)
+{
+/* int dg = abs(ig - g); */
+int dg = ((ig > g) ? ig - g : g - ig);
+int dt = dr + dg;
+int dm = ((dr > dg) ? dr : dg);
+int index_g = index_r | (ig << PNG_DITHER_BLUE_BITS);
+for (ib = 0; ib < num_blue; ib++)
+{
+int d_index = index_g | ib;
+/* int db = abs(ib - b); */
+int db = ((ib > b) ? ib - b : b - ib);
+int dmax = ((dm > db) ? dm : db);
+int d = dmax + dt + db;
+if (d < (int)distance[d_index])
+{
+distance[d_index] = (png_byte)d;
+png_ptr->palette_lookup[d_index] = (png_byte)i;
+}
+}
+}
+}
+}
+png_free(png_ptr, distance);
+}
+}
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+/* Transform the image from the file_gamma to the screen_gamma.  We
+* only do transformations on images where the file_gamma and screen_gamma
+* are not close reciprocals, otherwise it slows things down slightly, and
+* also needlessly introduces small errors.
+*
+* We will turn off gamma transformation later if no semitransparent entries
+* are present in the tRNS array for palette images.  We can't do it here
+* because we don't necessarily have the tRNS chunk yet.
+*/
+void PNGAPI
+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 ((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))
+png_ptr->transformations |= PNG_GAMMA;
+png_ptr->gamma = (float)file_gamma;
+png_ptr->screen_gamma = (float)scrn_gamma;
+}
+#endif
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+/* Expand paletted images to RGB, expand grayscale images of
+* less than 8-bit depth to 8-bit depth, and expand tRNS chunks
+* to alpha channels.
+*/
+void PNGAPI
+png_set_expand(png_structp png_ptr)
+{
+png_debug(1, "in png_set_expand\n");
+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
+*  to png_set_expand().  However, it is entirely reasonable that someone
+*  might wish to expand an indexed image to RGB but *not* expand a single,
+*  fully transparent palette entry to a full alpha channel--perhaps instead
+*  convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
+*  the transparent color with a particular RGB value, or drop tRNS entirely.
+*  IOW, a future version of the library may make the transformations flag
+*  a bit more fine-grained, with separate bits for each of these three
+*  functions.
+*
+*  More to the point, these functions make it obvious what libpng will be
+*  doing, whereas "expand" can (and does) mean any number of things.
+*
+*  GRP 20060307: In libpng-1.4.0, png_set_gray_1_2_4_to_8() was modified
+*  to expand only the sample depth but not to expand the tRNS to alpha.
+*/
+/* Expand paletted images to RGB. */
+void PNGAPI
+png_set_palette_to_rgb(png_structp png_ptr)
+{
+png_debug(1, "in png_set_palette_to_rgb\n");
+if(png_ptr == NULL) return;
+png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
+}
+#if !defined(PNG_1_0_X)
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+void PNGAPI
+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;
+png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
+}
+#endif
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+/* Deprecated as of libpng-1.2.9 */
+void PNGAPI
+png_set_gray_1_2_4_to_8(png_structp png_ptr)
+{
+png_debug(1, "in png_set_gray_1_2_4_to_8\n");
+if(png_ptr == NULL) return;
+png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif
+/* Expand tRNS chunks to alpha channels. */
+void PNGAPI
+png_set_tRNS_to_alpha(png_structp png_ptr)
+{
+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) */
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+void PNGAPI
+png_set_gray_to_rgb(png_structp png_ptr)
+{
+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
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+#if defined(PNG_FLOATING_POINT_SUPPORTED)
+/* Convert a RGB image to a grayscale of the same width.  This allows us,
+* for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
+*/
+void PNGAPI
+png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
+double green)
+{
+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;
+png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
+}
+#endif
+void PNGAPI
+png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
+png_fixed_point red, png_fixed_point green)
+{
+png_debug(1, "in png_set_rgb_to_gray\n");
+if(png_ptr == NULL) return;
+switch(error_action)
+{
+case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
+break;
+case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
+break;
+case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
+}
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+png_ptr->transformations |= PNG_EXPAND;
+#else
+{
+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)
+{
+red_int   =  6968; /* .212671 * 32768 + .5 */
+green_int = 23434; /* .715160 * 32768 + .5 */
+}
+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);
+}
+else
+{
+png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
+red_int   =  6968;
+green_int = 23434;
+}
+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);
+}
+}
+#endif
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
+defined(PNG_LEGACY_SUPPORTED)
+void PNGAPI
+png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
+read_user_transform_fn)
+{
+png_debug(1, "in png_set_read_user_transform_fn\n");
+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)
+png_warning(png_ptr,
+"This version of libpng does not support user transforms");
+#endif
+}
+#endif
+/* Initialize everything needed for the read.  This includes modifying
+* the palette.
+*/
+void /* PRIVATE */
+png_init_read_transformations(png_structp png_ptr)
+{
+png_debug(1, "in png_init_read_transformations\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+if(png_ptr != NULL)
+#endif
+{
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \
+|| defined(PNG_READ_GAMMA_SUPPORTED)
+int color_type = png_ptr->color_type;
+#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))
+{
+if (!(color_type & PNG_COLOR_MASK_COLOR))  /* i.e., GRAY or GRAY_ALPHA */
+{
+/* expand background and tRNS chunks */
+switch (png_ptr->bit_depth)
+{
+case 1:
+png_ptr->background.gray *= (png_uint_16)0xff;
+png_ptr->background.red = png_ptr->background.green
+=  png_ptr->background.blue = png_ptr->background.gray;
+if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+{
+png_ptr->trans_values.gray *= (png_uint_16)0xff;
+png_ptr->trans_values.red = png_ptr->trans_values.green
+= png_ptr->trans_values.blue = png_ptr->trans_values.gray;
+}
+break;
+case 2:
+png_ptr->background.gray *= (png_uint_16)0x55;
+png_ptr->background.red = png_ptr->background.green
+= png_ptr->background.blue = png_ptr->background.gray;
+if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+{
+png_ptr->trans_values.gray *= (png_uint_16)0x55;
+png_ptr->trans_values.red = png_ptr->trans_values.green
+= png_ptr->trans_values.blue = png_ptr->trans_values.gray;
+}
+break;
+case 4:
+png_ptr->background.gray *= (png_uint_16)0x11;
+png_ptr->background.red = png_ptr->background.green
+= png_ptr->background.blue = png_ptr->background.gray;
+if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+{
+png_ptr->trans_values.gray *= (png_uint_16)0x11;
+png_ptr->trans_values.red = png_ptr->trans_values.green
+= png_ptr->trans_values.blue = png_ptr->trans_values.gray;
+}
+break;
+case 8:
+case 16:
+png_ptr->background.red = png_ptr->background.green
+= png_ptr->background.blue = png_ptr->background.gray;
+break;
+}
+}
+else if (color_type == PNG_COLOR_TYPE_PALETTE)
+{
+png_ptr->background.red   =
+png_ptr->palette[png_ptr->background.index].red;
+png_ptr->background.green =
+png_ptr->palette[png_ptr->background.index].green;
+png_ptr->background.blue  =
+png_ptr->palette[png_ptr->background.index].blue;
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+if (png_ptr->transformations & PNG_INVERT_ALPHA)
+{
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+#endif
+{
+/* invert the alpha channel (in tRNS) unless the pixels are
+going to be expanded, in which case leave it for later */
+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]);
+}
+}
+#endif
+}
+}
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
+png_ptr->background_1 = png_ptr->background;
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
+&& (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
+< PNG_GAMMA_THRESHOLD))
+{
+int i,k;
+k=0;
+for (i=0; i<png_ptr->num_trans; i++)
+{
+if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff)
+k=1; /* partial transparency is present */
+}
+if (k == 0)
+png_ptr->transformations &= ~PNG_GAMMA;
+}
+if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
+png_ptr->gamma != 0.0)
+{
+png_build_gamma_table(png_ptr);
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+if (png_ptr->transformations & PNG_BACKGROUND)
+{
+if (color_type == PNG_COLOR_TYPE_PALETTE)
+{
+/* could skip if no transparency and
+*/
+png_color back, back_1;
+png_colorp palette = png_ptr->palette;
+int num_palette = png_ptr->num_palette;
+int i;
+if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
+{
+back.red = png_ptr->gamma_table[png_ptr->background.red];
+back.green = png_ptr->gamma_table[png_ptr->background.green];
+back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+}
+else
+{
+double g, gs;
+switch (png_ptr->background_gamma_type)
+{
+case PNG_BACKGROUND_GAMMA_SCREEN:
+g = (png_ptr->screen_gamma);
+gs = 1.0;
+break;
+case PNG_BACKGROUND_GAMMA_FILE:
+g = 1.0 / (png_ptr->gamma);
+gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+break;
+case PNG_BACKGROUND_GAMMA_UNIQUE:
+g = 1.0 / (png_ptr->background_gamma);
+gs = 1.0 / (png_ptr->background_gamma *
+png_ptr->screen_gamma);
+break;
+default:
+g = 1.0;    /* back_1 */
+gs = 1.0;   /* back */
+}
+if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD)
+{
+back.red   = (png_byte)png_ptr->background.red;
+back.green = (png_byte)png_ptr->background.green;
+back.blue  = (png_byte)png_ptr->background.blue;
+}
+else
+{
+back.red = (png_byte)(pow(
+(double)png_ptr->background.red/255, gs) * 255.0 + .5);
+back.green = (png_byte)(pow(
+(double)png_ptr->background.green/255, gs) * 255.0 + .5);
+back.blue = (png_byte)(pow(
+(double)png_ptr->background.blue/255, gs) * 255.0 + .5);
+}
+back_1.red = (png_byte)(pow(
+(double)png_ptr->background.red/255, g) * 255.0 + .5);
+back_1.green = (png_byte)(pow(
+(double)png_ptr->background.green/255, g) * 255.0 + .5);
+back_1.blue = (png_byte)(pow(
+(double)png_ptr->background.blue/255, g) * 255.0 + .5);
+}
+for (i = 0; i < num_palette; i++)
+{
+if (i < (int)png_ptr->num_trans && png_ptr->trans[i] != 0xff)
+{
+if (png_ptr->trans[i] == 0)
+{
+palette[i] = back;
+}
+else /* if (png_ptr->trans[i] != 0xff) */
+{
+png_byte v, w;
+v = png_ptr->gamma_to_1[palette[i].red];
+png_composite(w, v, png_ptr->trans[i], back_1.red);
+palette[i].red = png_ptr->gamma_from_1[w];
+v = png_ptr->gamma_to_1[palette[i].green];
+png_composite(w, v, png_ptr->trans[i], back_1.green);
+palette[i].green = png_ptr->gamma_from_1[w];
+v = png_ptr->gamma_to_1[palette[i].blue];
+png_composite(w, v, png_ptr->trans[i], back_1.blue);
+palette[i].blue = png_ptr->gamma_from_1[w];
+}
+}
+else
+{
+palette[i].red = png_ptr->gamma_table[palette[i].red];
+palette[i].green = png_ptr->gamma_table[palette[i].green];
+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
+/* color_type != PNG_COLOR_TYPE_PALETTE */
+{
+double m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1);
+double g = 1.0;
+double gs = 1.0;
+switch (png_ptr->background_gamma_type)
+{
+case PNG_BACKGROUND_GAMMA_SCREEN:
+g = (png_ptr->screen_gamma);
+gs = 1.0;
+break;
+case PNG_BACKGROUND_GAMMA_FILE:
+g = 1.0 / (png_ptr->gamma);
+gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+break;
+case PNG_BACKGROUND_GAMMA_UNIQUE:
+g = 1.0 / (png_ptr->background_gamma);
+gs = 1.0 / (png_ptr->background_gamma *
+png_ptr->screen_gamma);
+break;
+}
+png_ptr->background_1.gray = (png_uint_16)(pow(
+(double)png_ptr->background.gray / m, g) * m + .5);
+png_ptr->background.gray = (png_uint_16)(pow(
+(double)png_ptr->background.gray / m, gs) * m + .5);
+if ((png_ptr->background.red != png_ptr->background.green) ||
+(png_ptr->background.red != png_ptr->background.blue) ||
+(png_ptr->background.red != png_ptr->background.gray))
+{
+/* RGB or RGBA with color background */
+png_ptr->background_1.red = (png_uint_16)(pow(
+(double)png_ptr->background.red / m, g) * m + .5);
+png_ptr->background_1.green = (png_uint_16)(pow(
+(double)png_ptr->background.green / m, g) * m + .5);
+png_ptr->background_1.blue = (png_uint_16)(pow(
+(double)png_ptr->background.blue / m, g) * m + .5);
+png_ptr->background.red = (png_uint_16)(pow(
+(double)png_ptr->background.red / m, gs) * m + .5);
+png_ptr->background.green = (png_uint_16)(pow(
+(double)png_ptr->background.green / m, gs) * m + .5);
+png_ptr->background.blue = (png_uint_16)(pow(
+(double)png_ptr->background.blue / m, gs) * m + .5);
+}
+else
+{
+/* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
+png_ptr->background_1.red = png_ptr->background_1.green
+= png_ptr->background_1.blue = png_ptr->background_1.gray;
+png_ptr->background.red = png_ptr->background.green
+= png_ptr->background.blue = png_ptr->background.gray;
+}
+}
+}
+else
+/* transformation does not include PNG_BACKGROUND */
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+if (color_type == PNG_COLOR_TYPE_PALETTE)
+{
+png_colorp palette = png_ptr->palette;
+int num_palette = png_ptr->num_palette;
+int i;
+for (i = 0; i < num_palette; i++)
+{
+palette[i].red = png_ptr->gamma_table[palette[i].red];
+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)
+else
+#endif
+#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+/* No GAMMA transformation */
+if ((png_ptr->transformations & PNG_BACKGROUND) &&
+(color_type == PNG_COLOR_TYPE_PALETTE))
+{
+int i;
+int istop = (int)png_ptr->num_trans;
+png_color back;
+png_colorp palette = png_ptr->palette;
+back.red   = (png_byte)png_ptr->background.red;
+back.green = (png_byte)png_ptr->background.green;
+back.blue  = (png_byte)png_ptr->background.blue;
+for (i = 0; i < istop; i++)
+{
+if (png_ptr->trans[i] == 0)
+{
+palette[i] = back;
+}
+else if (png_ptr->trans[i] != 0xff)
+{
+/* The png_composite() macro is defined in png.h */
+png_composite(palette[i].red, palette[i].red,
+png_ptr->trans[i], back.red);
+png_composite(palette[i].green, palette[i].green,
+png_ptr->trans[i], back.green);
+png_composite(palette[i].blue, palette[i].blue,
+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 */
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+if ((png_ptr->transformations & PNG_SHIFT) &&
+(color_type == PNG_COLOR_TYPE_PALETTE))
+{
+png_uint_16 i;
+png_uint_16 istop = png_ptr->num_palette;
+int sr = 8 - png_ptr->sig_bit.red;
+int sg = 8 - png_ptr->sig_bit.green;
+int sb = 8 - png_ptr->sig_bit.blue;
+if (sr < 0 || sr > 8)
+sr = 0;
+if (sg < 0 || sg > 8)
+sg = 0;
+if (sb < 0 || sb > 8)
+sb = 0;
+for (i = 0; i < istop; i++)
+{
+png_ptr->palette[i].red >>= sr;
+png_ptr->palette[i].green >>= sg;
+png_ptr->palette[i].blue >>= sb;
+}
+}
+#endif  /* PNG_READ_SHIFT_SUPPORTED */
+}
+#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
+&& !defined(PNG_READ_BACKGROUND_SUPPORTED)
+if(png_ptr)
+return;
+#endif
+}
+/* Modify the info structure to reflect the transformations.  The
+* info should be updated so a PNG file could be written with it,
+* assuming the transformations result in valid PNG data.
+*/
+void /* PRIVATE */
+png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
+{
+png_debug(1, "in png_read_transform_info\n");
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+if (png_ptr->transformations & PNG_EXPAND)
+{
+if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+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;
+info_ptr->bit_depth = 8;
+info_ptr->num_trans = 0;
+}
+else
+{
+if (png_ptr->num_trans)
+{
+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;
+info_ptr->num_trans = 0;
+}
+}
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+if (png_ptr->transformations & PNG_BACKGROUND)
+{
+info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
+info_ptr->num_trans = 0;
+info_ptr->background = png_ptr->background;
+}
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (png_ptr->transformations & PNG_GAMMA)
+{
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+info_ptr->gamma = png_ptr->gamma;
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+info_ptr->int_gamma = png_ptr->int_gamma;
+#endif
+}
+#endif
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))
+info_ptr->bit_depth = 8;
+#endif
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
+#endif
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
+#endif
+#if defined(PNG_READ_DITHER_SUPPORTED)
+if (png_ptr->transformations & PNG_DITHER)
+{
+if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+(info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
+png_ptr->palette_lookup && info_ptr->bit_depth == 8)
+{
+info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
+}
+}
+#endif
+#if defined(PNG_READ_PACK_SUPPORTED)
+if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
+info_ptr->bit_depth = 8;
+#endif
+if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+info_ptr->channels = 1;
+else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+info_ptr->channels = 3;
+else
+info_ptr->channels = 1;
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
+info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
+#endif
+if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+info_ptr->channels++;
+#if defined(PNG_READ_FILLER_SUPPORTED)
+/* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
+if ((png_ptr->transformations & PNG_FILLER) &&
+((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+(info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
+{
+info_ptr->channels++;
+/* if adding a true alpha channel not just filler */
+#if !defined(PNG_1_0_X)
+if (png_ptr->transformations & PNG_ADD_ALPHA)
+info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+#endif
+}
+#endif
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
+defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+if(png_ptr->transformations & PNG_USER_TRANSFORM)
+{
+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)
+info_ptr->channels = png_ptr->user_transform_channels;
+}
+#endif
+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);
+#if !defined(PNG_READ_EXPAND_SUPPORTED)
+if(png_ptr)
+return;
+#endif
+}
+/* Transform the row.  The order of transformations is significant,
+* and is very touchy.  If you add a transformation, take care to
+* decide how it fits in with the other transformations here.
+*/
+void /* PRIVATE */
+png_do_read_transformations(png_structp png_ptr)
+{
+png_debug(1, "in png_do_read_transformations\n");
+if (png_ptr->row_buf == NULL)
+{
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+char msg[50];
+png_snprintf2(msg, 50,
+"NULL row buffer for row %ld, pass %d", 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)
+if (png_ptr->transformations & PNG_EXPAND)
+{
+if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
+{
+png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
+png_ptr->palette, png_ptr->trans, png_ptr->num_trans);
+}
+else
+{
+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
+png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
+NULL);
+}
+}
+#endif
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
+png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
+PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA));
+#endif
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+{
+int rgb_error =
+png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1);
+if(rgb_error)
+{
+png_ptr->rgb_to_gray_status=1;
+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) ==
+PNG_RGB_TO_GRAY_ERR)
+png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+}
+}
+#endif
+/*
+From Andreas Dilger e-mail to png-implement, 26 March 1998:
+In most cases, the "simple transparency" should be done prior to doing
+gray-to-RGB, or you will have to test 3x as many bytes to check if a
+pixel is transparent.  You would also need to make sure that the
+transparency information is upgraded to RGB.
+To summarize, the current flow is:
+- Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+with background "in place" if transparent,
+convert to RGB if necessary
+- Gray + alpha -> composite with gray background and remove alpha bytes,
+convert to RGB if necessary
+To support RGB backgrounds for gray images we need:
+- Gray + simple transparency -> convert to RGB + simple transparency, compare
+3 or 6 bytes and composite with background
+"in place" if transparent (3x compare/pixel
+compared to doing composite with gray bkgrnd)
+- Gray + alpha -> convert to RGB + alpha, composite with background and
+remove alpha bytes (3x float operations/pixel
+compared with composite on gray background)
+Greg's change will do this.  The reason it wasn't done before is for
+performance, as this increases the per-pixel operations.  If we would check
+in advance if the background was gray or RGB, and position the gray-to-RGB
+transform appropriately, then it would save a lot of work/time.
+*/
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+/* if gray -> RGB, do so now only if background is non-gray; else do later
+* for performance reasons */
+if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+!(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+if ((png_ptr->transformations & PNG_BACKGROUND) &&
+((png_ptr->num_trans != 0 ) ||
+(png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
+png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
+&(png_ptr->trans_values), &(png_ptr->background)
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+, &(png_ptr->background_1),
+png_ptr->gamma_table, png_ptr->gamma_from_1,
+png_ptr->gamma_to_1, png_ptr->gamma_16_table,
+png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
+png_ptr->gamma_shift
+#endif
+);
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if ((png_ptr->transformations & PNG_GAMMA) &&
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+!((png_ptr->transformations & PNG_BACKGROUND) &&
+((png_ptr->num_trans != 0) ||
+(png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
+#endif
+(png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
+png_ptr->gamma_table, png_ptr->gamma_16_table,
+png_ptr->gamma_shift);
+#endif
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+if (png_ptr->transformations & PNG_16_TO_8)
+png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_DITHER_SUPPORTED)
+if (png_ptr->transformations & PNG_DITHER)
+{
+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)
+png_error(png_ptr, "png_do_dither returned rowbytes=0");
+}
+#endif
+#if defined(PNG_READ_INVERT_SUPPORTED)
+if (png_ptr->transformations & PNG_INVERT_MONO)
+png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+if (png_ptr->transformations & PNG_SHIFT)
+png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
+&(png_ptr->shift));
+#endif
+#if defined(PNG_READ_PACK_SUPPORTED)
+if (png_ptr->transformations & PNG_PACK)
+png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_BGR_SUPPORTED)
+if (png_ptr->transformations & PNG_BGR)
+png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+if (png_ptr->transformations & PNG_PACKSWAP)
+png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+/* if gray -> RGB, do so now only if we did not do so above */
+if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_FILLER_SUPPORTED)
+if (png_ptr->transformations & PNG_FILLER)
+png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
+(png_uint_32)png_ptr->filler, png_ptr->flags);
+#endif
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+if (png_ptr->transformations & PNG_INVERT_ALPHA)
+png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+if (png_ptr->transformations & PNG_SWAP_ALPHA)
+png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_SWAP_SUPPORTED)
+if (png_ptr->transformations & PNG_SWAP_BYTES)
+png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+if (png_ptr->transformations & PNG_USER_TRANSFORM)
+{
+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:     */
+/*  png_uint_32 width;          width of row */
+/*  png_uint_32 rowbytes;       number of bytes in row */
+/*  png_byte color_type;        color type of pixels */
+/*  png_byte bit_depth;         bit depth of samples */
+/*  png_byte channels;          number of channels (1-4) */
+/*  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)
+png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
+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 *
+png_ptr->row_info.channels);
+png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+png_ptr->row_info.width);
+}
+#endif
+}
+#if defined(PNG_READ_PACK_SUPPORTED)
+/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
+* without changing the actual values.  Thus, if you had a row with
+* a bit depth of 1, you would end up with bytes that only contained
+* the numbers 0 or 1.  If you would rather they contain 0 and 255, use
+* png_do_shift() after this.
+*/
+void /* PRIVATE */
+png_do_unpack(png_row_infop row_info, png_bytep row)
+{
+png_debug(1, "in png_do_unpack\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+if (row != NULL && row_info != NULL && row_info->bit_depth < 8)
+#else
+if (row_info->bit_depth < 8)
+#endif
+{
+png_uint_32 i;
+png_uint_32 row_width=row_info->width;
+switch (row_info->bit_depth)
+{
+case 1:
+{
+png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
+png_bytep dp = row + (png_size_t)row_width - 1;
+png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
+for (i = 0; i < row_width; i++)
+{
+*dp = (png_byte)((*sp >> shift) & 0x01);
+if (shift == 7)
+{
+shift = 0;
+sp--;
+}
+else
+shift++;
+dp--;
+}
+break;
+}
+case 2:
+{
+png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
+png_bytep dp = row + (png_size_t)row_width - 1;
+png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+for (i = 0; i < row_width; i++)
+{
+*dp = (png_byte)((*sp >> shift) & 0x03);
+if (shift == 6)
+{
+shift = 0;
+sp--;
+}
+else
+shift += 2;
+dp--;
+}
+break;
+}
+case 4:
+{
+png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
+png_bytep dp = row + (png_size_t)row_width - 1;
+png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+for (i = 0; i < row_width; i++)
+{
+*dp = (png_byte)((*sp >> shift) & 0x0f);
+if (shift == 4)
+{
+shift = 0;
+sp--;
+}
+else
+shift = 4;
+dp--;
+}
+break;
+}
+}
+row_info->bit_depth = 8;
+row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+row_info->rowbytes = row_width * row_info->channels;
+}
+}
+#endif
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+/* Reverse the effects of png_do_shift.  This routine merely shifts the
+* pixels back to their significant bits values.  Thus, if you have
+* a row of bit depth 8, but only 5 are significant, this will shift
+* the values back to 0 through 31.
+*/
+void /* PRIVATE */
+png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
+{
+png_debug(1, "in png_do_unshift\n");
+if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL && row_info != NULL && sig_bits != NULL &&
+#endif
+row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+{
+int shift[4];
+int channels = 0;
+int c;
+png_uint_16 value = 0;
+png_uint_32 row_width = row_info->width;
+if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+{
+shift[channels++] = row_info->bit_depth - sig_bits->red;
+shift[channels++] = row_info->bit_depth - sig_bits->green;
+shift[channels++] = row_info->bit_depth - sig_bits->blue;
+}
+else
+{
+shift[channels++] = row_info->bit_depth - sig_bits->gray;
+}
+if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+{
+shift[channels++] = row_info->bit_depth - sig_bits->alpha;
+}
+for (c = 0; c < channels; c++)
+{
+if (shift[c] <= 0)
+shift[c] = 0;
+else
+value = 1;
+}
+if (!value)
+return;
+switch (row_info->bit_depth)
+{
+case 2:
+{
+png_bytep bp;
+png_uint_32 i;
+png_uint_32 istop = row_info->rowbytes;
+for (bp = row, i = 0; i < istop; i++)
+{
+*bp >>= 1;
+*bp++ &= 0x55;
+}
+break;
+}
+case 4:
+{
+png_bytep bp = row;
+png_uint_32 i;
+png_uint_32 istop = row_info->rowbytes;
+png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) |
+(png_byte)((int)0xf >> shift[0]));
+for (i = 0; i < istop; i++)
+{
+*bp >>= shift[0];
+*bp++ &= mask;
+}
+break;
+}
+case 8:
+{
+png_bytep bp = row;
+png_uint_32 i;
+png_uint_32 istop = row_width * channels;
+for (i = 0; i < istop; i++)
+{
+*bp++ >>= shift[i%channels];
+}
+break;
+}
+case 16:
+{
+png_bytep bp = row;
+png_uint_32 i;
+png_uint_32 istop = channels * row_width;
+for (i = 0; i < istop; i++)
+{
+value = (png_uint_16)((*bp << 8) + *(bp + 1));
+value >>= shift[i%channels];
+*bp++ = (png_byte)(value >> 8);
+*bp++ = (png_byte)(value & 0xff);
+}
+break;
+}
+}
+}
+}
+#endif
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+/* chop rows of bit depth 16 down to 8 */
+void /* PRIVATE */
+png_do_chop(png_row_infop row_info, png_bytep row)
+{
+png_debug(1, "in png_do_chop\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+if (row != NULL && row_info != NULL && row_info->bit_depth == 16)
+#else
+if (row_info->bit_depth == 16)
+#endif
+{
+png_bytep sp = row;
+png_bytep dp = row;
+png_uint_32 i;
+png_uint_32 istop = row_info->width * row_info->channels;
+for (i = 0; i<istop; i++, sp += 2, dp++)
+{
+#if defined(PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED)
+/* This does a more accurate scaling of the 16-bit color
+* value, rather than a simple low-byte truncation.
+*
+* What the ideal calculation should be:
+*   *dp = (((((png_uint_32)(*sp) << 8) |
+*          (png_uint_32)(*(sp + 1))) * 255 + 127) / (png_uint_32)65535L;
+*
+* GRR: no, I think this is what it really should be:
+*   *dp = (((((png_uint_32)(*sp) << 8) |
+*           (png_uint_32)(*(sp + 1))) + 128L) / (png_uint_32)257L;
+*
+* GRR: here's the exact calculation with shifts:
+*   temp = (((png_uint_32)(*sp) << 8) | (png_uint_32)(*(sp + 1))) + 128L;
+*   *dp = (temp - (temp >> 8)) >> 8;
+*
+* Approximate calculation with shift/add instead of multiply/divide:
+*   *dp = ((((png_uint_32)(*sp) << 8) |
+*          (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8;
+*
+* What we actually do to avoid extra shifting and conversion:
+*/
+*dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
+#else
+/* Simply discard the low order byte */
+*dp = *sp;
+#endif
+}
+row_info->bit_depth = 8;
+row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+row_info->rowbytes = row_info->width * row_info->channels;
+}
+}
+#endif
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+void /* PRIVATE */
+png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+png_debug(1, "in png_do_read_swap_alpha\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+if (row != NULL && row_info != NULL)
+#endif
+{
+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)
+{
+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;
+}
+}
+/* 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];
+}
+}
+}
+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;
+}
+}
+/* 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];
+}
+}
+}
+}
+}
+#endif
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+void /* PRIVATE */
+png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+png_debug(1, "in png_do_read_invert_alpha\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+if (row != NULL && row_info != NULL)
+#endif
+{
+png_uint_32 row_width = row_info->width;
+if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+{
+/* This inverts the alpha channel in RGBA */
+if (row_info->bit_depth == 8)
+{
+png_bytep sp = row + row_info->rowbytes;
+png_bytep dp = sp;
+png_uint_32 i;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = (png_byte)(255 - *(--sp));
+/*             This does nothing:
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+We can replace it with:
+*/
+sp-=3;
+dp=sp;
+}
+}
+/* This inverts the alpha channel in RRGGBBAA */
+else
+{
+png_bytep sp = row + row_info->rowbytes;
+png_bytep dp = sp;
+png_uint_32 i;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = (png_byte)(255 - *(--sp));
+*(--dp) = (png_byte)(255 - *(--sp));
+/*             This does nothing:
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+We can replace it with:
+*/
+sp-=6;
+dp=sp;
+}
+}
+}
+else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+{
+/* This inverts the alpha channel in GA */
+if (row_info->bit_depth == 8)
+{
+png_bytep sp = row + row_info->rowbytes;
+png_bytep dp = sp;
+png_uint_32 i;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = (png_byte)(255 - *(--sp));
+*(--dp) = *(--sp);
+}
+}
+/* This inverts the alpha channel in GGAA */
+else
+{
+png_bytep sp  = row + row_info->rowbytes;
+png_bytep dp = sp;
+png_uint_32 i;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = (png_byte)(255 - *(--sp));
+*(--dp) = (png_byte)(255 - *(--sp));
+/*
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*/
+sp-=2;
+dp=sp;
+}
+}
+}
+}
+}
+#endif
+#if defined(PNG_READ_FILLER_SUPPORTED)
+/* Add filler channel if we have RGB color */
+void /* PRIVATE */
+png_do_read_filler(png_row_infop row_info, png_bytep row,
+png_uint_32 filler, png_uint_32 flags)
+{
+png_uint_32 i;
+png_uint_32 row_width = row_info->width;
+png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
+png_byte lo_filler = (png_byte)(filler & 0xff);
+png_debug(1, "in png_do_read_filler\n");
+if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL  && row_info != NULL &&
+#endif
+row_info->color_type == PNG_COLOR_TYPE_GRAY)
+{
+if(row_info->bit_depth == 8)
+{
+/* This changes the data from G to GX */
+if (flags & PNG_FLAG_FILLER_AFTER)
+{
+png_bytep sp = row + (png_size_t)row_width;
+png_bytep dp =  sp + (png_size_t)row_width;
+for (i = 1; i < row_width; i++)
+{
+*(--dp) = lo_filler;
+*(--dp) = *(--sp);
+}
+*(--dp) = lo_filler;
+row_info->channels = 2;
+row_info->pixel_depth = 16;
+row_info->rowbytes = row_width * 2;
+}
+/* This changes the data from G to XG */
+else
+{
+png_bytep sp = row + (png_size_t)row_width;
+png_bytep dp = sp  + (png_size_t)row_width;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = *(--sp);
+*(--dp) = lo_filler;
+}
+row_info->channels = 2;
+row_info->pixel_depth = 16;
+row_info->rowbytes = row_width * 2;
+}
+}
+else if(row_info->bit_depth == 16)
+{
+/* This changes the data from GG to GGXX */
+if (flags & PNG_FLAG_FILLER_AFTER)
+{
+png_bytep sp = row + (png_size_t)row_width * 2;
+png_bytep dp = sp  + (png_size_t)row_width * 2;
+for (i = 1; i < row_width; i++)
+{
+*(--dp) = hi_filler;
+*(--dp) = lo_filler;
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+}
+*(--dp) = hi_filler;
+*(--dp) = lo_filler;
+row_info->channels = 2;
+row_info->pixel_depth = 32;
+row_info->rowbytes = row_width * 4;
+}
+/* This changes the data from GG to XXGG */
+else
+{
+png_bytep sp = row + (png_size_t)row_width * 2;
+png_bytep dp = sp  + (png_size_t)row_width * 2;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = hi_filler;
+*(--dp) = lo_filler;
+}
+row_info->channels = 2;
+row_info->pixel_depth = 32;
+row_info->rowbytes = row_width * 4;
+}
+}
+} /* COLOR_TYPE == GRAY */
+else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+{
+if(row_info->bit_depth == 8)
+{
+/* This changes the data from RGB to RGBX */
+if (flags & PNG_FLAG_FILLER_AFTER)
+{
+png_bytep sp = row + (png_size_t)row_width * 3;
+png_bytep dp = sp  + (png_size_t)row_width;
+for (i = 1; i < row_width; i++)
+{
+*(--dp) = lo_filler;
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+}
+*(--dp) = lo_filler;
+row_info->channels = 4;
+row_info->pixel_depth = 32;
+row_info->rowbytes = row_width * 4;
+}
+/* This changes the data from RGB to XRGB */
+else
+{
+png_bytep sp = row + (png_size_t)row_width * 3;
+png_bytep dp = sp + (png_size_t)row_width;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = lo_filler;
+}
+row_info->channels = 4;
+row_info->pixel_depth = 32;
+row_info->rowbytes = row_width * 4;
+}
+}
+else if(row_info->bit_depth == 16)
+{
+/* This changes the data from RRGGBB to RRGGBBXX */
+if (flags & PNG_FLAG_FILLER_AFTER)
+{
+png_bytep sp = row + (png_size_t)row_width * 6;
+png_bytep dp = sp  + (png_size_t)row_width * 2;
+for (i = 1; i < row_width; i++)
+{
+*(--dp) = hi_filler;
+*(--dp) = lo_filler;
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+}
+*(--dp) = hi_filler;
+*(--dp) = lo_filler;
+row_info->channels = 4;
+row_info->pixel_depth = 64;
+row_info->rowbytes = row_width * 8;
+}
+/* This changes the data from RRGGBB to XXRRGGBB */
+else
+{
+png_bytep sp = row + (png_size_t)row_width * 6;
+png_bytep dp = sp  + (png_size_t)row_width * 2;
+for (i = 0; i < row_width; i++)
+{
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = *(--sp);
+*(--dp) = hi_filler;
+*(--dp) = lo_filler;
+}
+row_info->channels = 4;
+row_info->pixel_depth = 64;
+row_info->rowbytes = row_width * 8;
+}
+}
+} /* COLOR_TYPE == RGB */
+}
+#endif
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+/* expand grayscale files to RGB, with or without alpha */
+void /* PRIVATE */
+png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
+{
+png_uint_32 i;
+png_uint_32 row_width = row_info->width;
+png_debug(1, "in png_do_gray_to_rgb\n");
+if (row_info->bit_depth >= 8 &&
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL && row_info != NULL &&
+#endif
+!(row_info->color_type & PNG_COLOR_MASK_COLOR))
+{
+if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+{
+if (row_info->bit_depth == 8)
+{
+png_bytep sp = row + (png_size_t)row_width - 1;
+png_bytep dp = sp  + (png_size_t)row_width * 2;
+for (i = 0; i < row_width; i++)
+{
+*(dp--) = *sp;
+*(dp--) = *sp;
+*(dp--) = *(sp--);
+}
+}
+else
+{
+png_bytep sp = row + (png_size_t)row_width * 2 - 1;
+png_bytep dp = sp  + (png_size_t)row_width * 4;
+for (i = 0; i < row_width; i++)
+{
+*(dp--) = *sp;
+*(dp--) = *(sp - 1);
+*(dp--) = *sp;
+*(dp--) = *(sp - 1);
+*(dp--) = *(sp--);
+*(dp--) = *(sp--);
+}
+}
+}
+else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+{
+if (row_info->bit_depth == 8)
+{
+png_bytep sp = row + (png_size_t)row_width * 2 - 1;
+png_bytep dp = sp  + (png_size_t)row_width * 2;
+for (i = 0; i < row_width; i++)
+{
+*(dp--) = *(sp--);
+*(dp--) = *sp;
+*(dp--) = *sp;
+*(dp--) = *(sp--);
+}
+}
+else
+{
+png_bytep sp = row + (png_size_t)row_width * 4 - 1;
+png_bytep dp = sp  + (png_size_t)row_width * 4;
+for (i = 0; i < row_width; i++)
+{
+*(dp--) = *(sp--);
+*(dp--) = *(sp--);
+*(dp--) = *sp;
+*(dp--) = *(sp - 1);
+*(dp--) = *sp;
+*(dp--) = *(sp - 1);
+*(dp--) = *(sp--);
+*(dp--) = *(sp--);
+}
+}
+}
+row_info->channels += (png_byte)2;
+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);
+}
+}
+#endif
+#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/>
+* Copyright (c) 1998-01-04 Charles Poynton poynton at inforamp.net
+*
+*     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+*
+*  We approximate this with
+*
+*     Y = 0.21268 * R    + 0.7151 * G    + 0.07217 * B
+*
+*  which can be expressed with integers as
+*
+*     Y = (6969 * R + 23434 * G + 2365 * B)/32768
+*
+*  The calculation is to be done in a linear colorspace.
+*
+*  Other integer coefficents can be used via png_set_rgb_to_gray().
+*/
+int /* PRIVATE */
+png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
+{
+png_uint_32 i;
+png_uint_32 row_width = row_info->width;
+int rgb_error = 0;
+png_debug(1, "in png_do_rgb_to_gray\n");
+if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL && row_info != NULL &&
+#endif
+(row_info->color_type & PNG_COLOR_MASK_COLOR))
+{
+png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff;
+if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+{
+if (row_info->bit_depth == 8)
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+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)
+{
+rgb_error |= 1;
+*(dp++) = png_ptr->gamma_from_1[
+(rc*red+gc*green+bc*blue)>>15];
+}
+else
+*(dp++) = *(sp-1);
+}
+}
+else
+#endif
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+png_byte red   = *(sp++);
+png_byte green = *(sp++);
+png_byte blue  = *(sp++);
+if(red != green || red != blue)
+{
+rgb_error |= 1;
+*(dp++) = (png_byte)((rc*red+gc*green+bc*blue)>>15);
+}
+else
+*(dp++) = *(sp-1);
+}
+}
+}
+else /* RGB bit_depth == 16 */
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+if (png_ptr->gamma_16_to_1 != NULL &&
+png_ptr->gamma_16_from_1 != NULL)
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 red, green, blue, w;
+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)
+w = red;
+else
+{
+png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>
+png_ptr->gamma_shift][red>>8];
+png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
+png_ptr->gamma_shift][green>>8];
+png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >>
+png_ptr->gamma_shift][blue>>8];
+png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
++ bc*blue_1)>>15);
+w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
+png_ptr->gamma_shift][gray16 >> 8];
+rgb_error |= 1;
+}
+*(dp++) = (png_byte)((w>>8) & 0xff);
+*(dp++) = (png_byte)(w & 0xff);
+}
+}
+else
+#endif
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 red, green, blue, gray16;
+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)
+rgb_error |= 1;
+gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
+*(dp++) = (png_byte)((gray16>>8) & 0xff);
+*(dp++) = (png_byte)(gray16 & 0xff);
+}
+}
+}
+}
+if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+{
+if (row_info->bit_depth == 8)
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+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)
+rgb_error |= 1;
+*(dp++) =  png_ptr->gamma_from_1
+[(rc*red + gc*green + bc*blue)>>15];
+*(dp++) = *(sp++);  /* alpha */
+}
+}
+else
+#endif
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+png_byte red   = *(sp++);
+png_byte green = *(sp++);
+png_byte blue  = *(sp++);
+if(red != green || red != blue)
+rgb_error |= 1;
+*(dp++) =  (png_byte)((rc*red + gc*green + bc*blue)>>15);
+*(dp++) = *(sp++);  /* alpha */
+}
+}
+}
+else /* RGBA bit_depth == 16 */
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+if (png_ptr->gamma_16_to_1 != NULL &&
+png_ptr->gamma_16_from_1 != NULL)
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 red, green, blue, w;
+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)
+w = red;
+else
+{
+png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>
+png_ptr->gamma_shift][red>>8];
+png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
+png_ptr->gamma_shift][green>>8];
+png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >>
+png_ptr->gamma_shift][blue>>8];
+png_uint_16 gray16  = (png_uint_16)((rc * red_1
++ gc * green_1 + bc * blue_1)>>15);
+w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
+png_ptr->gamma_shift][gray16 >> 8];
+rgb_error |= 1;
+}
+*(dp++) = (png_byte)((w>>8) & 0xff);
+*(dp++) = (png_byte)(w & 0xff);
+*(dp++) = *(sp++);  /* alpha */
+*(dp++) = *(sp++);
+}
+}
+else
+#endif
+{
+png_bytep sp = row;
+png_bytep dp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 red, green, blue, gray16;
+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)
+rgb_error |= 1;
+gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
+*(dp++) = (png_byte)((gray16>>8) & 0xff);
+*(dp++) = (png_byte)(gray16 & 0xff);
+*(dp++) = *(sp++);  /* alpha */
+*(dp++) = *(sp++);
+}
+}
+}
+}
+row_info->channels -= (png_byte)2;
+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);
+}
+return rgb_error;
+}
+#endif
+/* Build a grayscale palette.  Palette is assumed to be 1 << bit_depth
+* large of png_color.  This lets grayscale images be treated as
+* paletted.  Most useful for gamma correction and simplification
+* of code.
+*/
+void PNGAPI
+png_build_grayscale_palette(int bit_depth, png_colorp palette)
+{
+int num_palette;
+int color_inc;
+int i;
+int v;
+png_debug(1, "in png_do_build_grayscale_palette\n");
+if (palette == NULL)
+return;
+switch (bit_depth)
+{
+case 1:
+num_palette = 2;
+color_inc = 0xff;
+break;
+case 2:
+num_palette = 4;
+color_inc = 0x55;
+break;
+case 4:
+num_palette = 16;
+color_inc = 0x11;
+break;
+case 8:
+num_palette = 256;
+color_inc = 1;
+break;
+default:
+num_palette = 0;
+color_inc = 0;
+break;
+}
+for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
+{
+palette[i].red = (png_byte)v;
+palette[i].green = (png_byte)v;
+palette[i].blue = (png_byte)v;
+}
+}
+/* This function is currently unused.  Do we really need it? */
+#if defined(PNG_READ_DITHER_SUPPORTED) && defined(PNG_CORRECT_PALETTE_SUPPORTED)
+void /* PRIVATE */
+png_correct_palette(png_structp png_ptr, png_colorp palette,
+int num_palette)
+{
+png_debug(1, "in png_correct_palette\n");
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+if (png_ptr->transformations & (PNG_GAMMA | PNG_BACKGROUND))
+{
+png_color back, back_1;
+if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
+{
+back.red = png_ptr->gamma_table[png_ptr->background.red];
+back.green = png_ptr->gamma_table[png_ptr->background.green];
+back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+}
+else
+{
+double g;
+g = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma);
+if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_SCREEN ||
+fabs(g - 1.0) < PNG_GAMMA_THRESHOLD)
+{
+back.red = png_ptr->background.red;
+back.green = png_ptr->background.green;
+back.blue = png_ptr->background.blue;
+}
+else
+{
+back.red =
+(png_byte)(pow((double)png_ptr->background.red/255, g) *
+255.0 + 0.5);
+back.green =
+(png_byte)(pow((double)png_ptr->background.green/255, g) *
+255.0 + 0.5);
+back.blue =
+(png_byte)(pow((double)png_ptr->background.blue/255, g) *
+255.0 + 0.5);
+}
+g = 1.0 / png_ptr->background_gamma;
+back_1.red =
+(png_byte)(pow((double)png_ptr->background.red/255, g) *
+255.0 + 0.5);
+back_1.green =
+(png_byte)(pow((double)png_ptr->background.green/255, g) *
+255.0 + 0.5);
+back_1.blue =
+(png_byte)(pow((double)png_ptr->background.blue/255, g) *
+255.0 + 0.5);
+}
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+png_uint_32 i;
+for (i = 0; i < (png_uint_32)num_palette; i++)
+{
+if (i < png_ptr->num_trans && png_ptr->trans[i] == 0)
+{
+palette[i] = back;
+}
+else if (i < png_ptr->num_trans && png_ptr->trans[i] != 0xff)
+{
+png_byte v, w;
+v = png_ptr->gamma_to_1[png_ptr->palette[i].red];
+png_composite(w, v, png_ptr->trans[i], back_1.red);
+palette[i].red = png_ptr->gamma_from_1[w];
+v = png_ptr->gamma_to_1[png_ptr->palette[i].green];
+png_composite(w, v, png_ptr->trans[i], back_1.green);
+palette[i].green = png_ptr->gamma_from_1[w];
+v = png_ptr->gamma_to_1[png_ptr->palette[i].blue];
+png_composite(w, v, png_ptr->trans[i], back_1.blue);
+palette[i].blue = png_ptr->gamma_from_1[w];
+}
+else
+{
+palette[i].red = png_ptr->gamma_table[palette[i].red];
+palette[i].green = png_ptr->gamma_table[palette[i].green];
+palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+}
+}
+}
+else
+{
+int i;
+for (i = 0; i < num_palette; i++)
+{
+if (palette[i].red == (png_byte)png_ptr->trans_values.gray)
+{
+palette[i] = back;
+}
+else
+{
+palette[i].red = png_ptr->gamma_table[palette[i].red];
+palette[i].green = png_ptr->gamma_table[palette[i].green];
+palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+}
+}
+}
+}
+else
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (png_ptr->transformations & PNG_GAMMA)
+{
+int i;
+for (i = 0; i < num_palette; i++)
+{
+palette[i].red = png_ptr->gamma_table[palette[i].red];
+palette[i].green = png_ptr->gamma_table[palette[i].green];
+palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+}
+}
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+else
+#endif
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+if (png_ptr->transformations & PNG_BACKGROUND)
+{
+if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+png_color back;
+back.red   = (png_byte)png_ptr->background.red;
+back.green = (png_byte)png_ptr->background.green;
+back.blue  = (png_byte)png_ptr->background.blue;
+for (i = 0; i < (int)png_ptr->num_trans; i++)
+{
+if (png_ptr->trans[i] == 0)
+{
+palette[i].red = back.red;
+palette[i].green = back.green;
+palette[i].blue = back.blue;
+}
+else if (png_ptr->trans[i] != 0xff)
+{
+png_composite(palette[i].red, png_ptr->palette[i].red,
+png_ptr->trans[i], back.red);
+png_composite(palette[i].green, png_ptr->palette[i].green,
+png_ptr->trans[i], back.green);
+png_composite(palette[i].blue, png_ptr->palette[i].blue,
+png_ptr->trans[i], back.blue);
+}
+}
+}
+else /* assume grayscale palette (what else could it be?) */
+{
+int i;
+for (i = 0; i < num_palette; i++)
+{
+if (i == (png_byte)png_ptr->trans_values.gray)
+{
+palette[i].red = (png_byte)png_ptr->background.red;
+palette[i].green = (png_byte)png_ptr->background.green;
+palette[i].blue = (png_byte)png_ptr->background.blue;
+}
+}
+}
+}
+#endif
+}
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+/* Replace any alpha or transparency with the supplied background color.
+* "background" is already in the screen gamma, while "background_1" is
+* at a gamma of 1.0.  Paletted files have already been taken care of.
+*/
+void /* PRIVATE */
+png_do_background(png_row_infop row_info, png_bytep row,
+png_color_16p trans_values, png_color_16p background
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+, png_color_16p background_1,
+png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
+png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
+png_uint_16pp gamma_16_to_1, int gamma_shift
+#endif
+)
+{
+png_bytep sp, dp;
+png_uint_32 i;
+png_uint_32 row_width=row_info->width;
+int shift;
+png_debug(1, "in png_do_background\n");
+if (background != NULL &&
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL && row_info != NULL &&
+#endif
+(!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
+(row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_values)))
+{
+switch (row_info->color_type)
+{
+case PNG_COLOR_TYPE_GRAY:
+{
+switch (row_info->bit_depth)
+{
+case 1:
+{
+sp = row;
+shift = 7;
+for (i = 0; i < row_width; i++)
+{
+if ((png_uint_16)((*sp >> shift) & 0x01)
+== trans_values->gray)
+{
+*sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+*sp |= (png_byte)(background->gray << shift);
+}
+if (!shift)
+{
+shift = 7;
+sp++;
+}
+else
+shift--;
+}
+break;
+}
+case 2:
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (gamma_table != NULL)
+{
+sp = row;
+shift = 6;
+for (i = 0; i < row_width; i++)
+{
+if ((png_uint_16)((*sp >> shift) & 0x03)
+== trans_values->gray)
+{
+*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+*sp |= (png_byte)(background->gray << shift);
+}
+else
+{
+png_byte p = (png_byte)((*sp >> shift) & 0x03);
+png_byte g = (png_byte)((gamma_table [p | (p << 2) |
+(p << 4) | (p << 6)] >> 6) & 0x03);
+*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+*sp |= (png_byte)(g << shift);
+}
+if (!shift)
+{
+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)
+== trans_values->gray)
+{
+*sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+*sp |= (png_byte)(background->gray << shift);
+}
+if (!shift)
+{
+shift = 6;
+sp++;
+}
+else
+shift -= 2;
+}
+}
+break;
+}
+case 4:
+{
+#if defined(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)
+== trans_values->gray)
+{
+*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+*sp |= (png_byte)(background->gray << shift);
+}
+else
+{
+png_byte p = (png_byte)((*sp >> shift) & 0x0f);
+png_byte g = (png_byte)((gamma_table[p |
+(p << 4)] >> 4) & 0x0f);
+*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+*sp |= (png_byte)(g << shift);
+}
+if (!shift)
+{
+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)
+== trans_values->gray)
+{
+*sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+*sp |= (png_byte)(background->gray << shift);
+}
+if (!shift)
+{
+shift = 4;
+sp++;
+}
+else
+shift -= 4;
+}
+}
+break;
+}
+case 8:
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (gamma_table != NULL)
+{
+sp = row;
+for (i = 0; i < row_width; i++, sp++)
+{
+if (*sp == trans_values->gray)
+{
+*sp = (png_byte)background->gray;
+}
+else
+{
+*sp = gamma_table[*sp];
+}
+}
+}
+else
+#endif
+{
+sp = row;
+for (i = 0; i < row_width; i++, sp++)
+{
+if (*sp == trans_values->gray)
+{
+*sp = (png_byte)background->gray;
+}
+}
+}
+break;
+}
+case 16:
+{
+#if defined(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 == trans_values->gray)
+{
+/* background is already in screen gamma */
+*sp = (png_byte)((background->gray >> 8) & 0xff);
+*(sp + 1) = (png_byte)(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 == trans_values->gray)
+{
+*sp = (png_byte)((background->gray >> 8) & 0xff);
+*(sp + 1) = (png_byte)(background->gray & 0xff);
+}
+}
+}
+break;
+}
+}
+break;
+}
+case PNG_COLOR_TYPE_RGB:
+{
+if (row_info->bit_depth == 8)
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (gamma_table != NULL)
+{
+sp = row;
+for (i = 0; i < row_width; i++, sp += 3)
+{
+if (*sp == trans_values->red &&
+*(sp + 1) == trans_values->green &&
+*(sp + 2) == trans_values->blue)
+{
+*sp = (png_byte)background->red;
+*(sp + 1) = (png_byte)background->green;
+*(sp + 2) = (png_byte)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 == trans_values->red &&
+*(sp + 1) == trans_values->green &&
+*(sp + 2) == trans_values->blue)
+{
+*sp = (png_byte)background->red;
+*(sp + 1) = (png_byte)background->green;
+*(sp + 2) = (png_byte)background->blue;
+}
+}
+}
+}
+else /* if (row_info->bit_depth == 16) */
+{
+#if defined(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 == trans_values->red && g == trans_values->green &&
+b == trans_values->blue)
+{
+/* background is already in screen gamma */
+*sp = (png_byte)((background->red >> 8) & 0xff);
+*(sp + 1) = (png_byte)(background->red & 0xff);
+*(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
+*(sp + 3) = (png_byte)(background->green & 0xff);
+*(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+*(sp + 5) = (png_byte)(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 == trans_values->red && g == trans_values->green &&
+b == trans_values->blue)
+{
+*sp = (png_byte)((background->red >> 8) & 0xff);
+*(sp + 1) = (png_byte)(background->red & 0xff);
+*(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
+*(sp + 3) = (png_byte)(background->green & 0xff);
+*(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+*(sp + 5) = (png_byte)(background->blue & 0xff);
+}
+}
+}
+}
+break;
+}
+case PNG_COLOR_TYPE_GRAY_ALPHA:
+{
+if (row_info->bit_depth == 8)
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+gamma_table != NULL)
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 2, dp++)
+{
+png_uint_16 a = *(sp + 1);
+if (a == 0xff)
+{
+*dp = gamma_table[*sp];
+}
+else if (a == 0)
+{
+/* background is already in screen gamma */
+*dp = (png_byte)background->gray;
+}
+else
+{
+png_byte v, w;
+v = gamma_to_1[*sp];
+png_composite(w, v, a, background_1->gray);
+*dp = gamma_from_1[w];
+}
+}
+}
+else
+#endif
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 2, dp++)
+{
+png_byte a = *(sp + 1);
+if (a == 0xff)
+{
+*dp = *sp;
+}
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+else if (a == 0)
+{
+*dp = (png_byte)background->gray;
+}
+else
+{
+png_composite(*dp, *sp, a, background_1->gray);
+}
+#else
+*dp = (png_byte)background->gray;
+#endif
+}
+}
+}
+else /* if (png_ptr->bit_depth == 16) */
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+gamma_16_to_1 != NULL)
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+{
+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];
+*dp = (png_byte)((v >> 8) & 0xff);
+*(dp + 1) = (png_byte)(v & 0xff);
+}
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+else if (a == 0)
+#else
+else
+#endif
+{
+/* background is already in screen gamma */
+*dp = (png_byte)((background->gray >> 8) & 0xff);
+*(dp + 1) = (png_byte)(background->gray & 0xff);
+}
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+else
+{
+png_uint_16 g, v, w;
+g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+png_composite_16(v, g, a, background_1->gray);
+w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
+*dp = (png_byte)((w >> 8) & 0xff);
+*(dp + 1) = (png_byte)(w & 0xff);
+}
+#endif
+}
+}
+else
+#endif
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+{
+png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
+if (a == (png_uint_16)0xffff)
+{
+png_memcpy(dp, sp, 2);
+}
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+else if (a == 0)
+#else
+else
+#endif
+{
+*dp = (png_byte)((background->gray >> 8) & 0xff);
+*(dp + 1) = (png_byte)(background->gray & 0xff);
+}
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+else
+{
+png_uint_16 g, v;
+g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+png_composite_16(v, g, a, background_1->gray);
+*dp = (png_byte)((v >> 8) & 0xff);
+*(dp + 1) = (png_byte)(v & 0xff);
+}
+#endif
+}
+}
+}
+break;
+}
+case PNG_COLOR_TYPE_RGB_ALPHA:
+{
+if (row_info->bit_depth == 8)
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+gamma_table != NULL)
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+{
+png_byte a = *(sp + 3);
+if (a == 0xff)
+{
+*dp = gamma_table[*sp];
+*(dp + 1) = gamma_table[*(sp + 1)];
+*(dp + 2) = gamma_table[*(sp + 2)];
+}
+else if (a == 0)
+{
+/* background is already in screen gamma */
+*dp = (png_byte)background->red;
+*(dp + 1) = (png_byte)background->green;
+*(dp + 2) = (png_byte)background->blue;
+}
+else
+{
+png_byte v, w;
+v = gamma_to_1[*sp];
+png_composite(w, v, a, background_1->red);
+*dp = gamma_from_1[w];
+v = gamma_to_1[*(sp + 1)];
+png_composite(w, v, a, background_1->green);
+*(dp + 1) = gamma_from_1[w];
+v = gamma_to_1[*(sp + 2)];
+png_composite(w, v, a, background_1->blue);
+*(dp + 2) = gamma_from_1[w];
+}
+}
+}
+else
+#endif
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+{
+png_byte a = *(sp + 3);
+if (a == 0xff)
+{
+*dp = *sp;
+*(dp + 1) = *(sp + 1);
+*(dp + 2) = *(sp + 2);
+}
+else if (a == 0)
+{
+*dp = (png_byte)background->red;
+*(dp + 1) = (png_byte)background->green;
+*(dp + 2) = (png_byte)background->blue;
+}
+else
+{
+png_composite(*dp, *sp, a, background->red);
+png_composite(*(dp + 1), *(sp + 1), a,
+background->green);
+png_composite(*(dp + 2), *(sp + 2), a,
+background->blue);
+}
+}
+}
+}
+else /* if (row_info->bit_depth == 16) */
+{
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+gamma_16_to_1 != NULL)
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+{
+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];
+*dp = (png_byte)((v >> 8) & 0xff);
+*(dp + 1) = (png_byte)(v & 0xff);
+v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+*(dp + 2) = (png_byte)((v >> 8) & 0xff);
+*(dp + 3) = (png_byte)(v & 0xff);
+v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+*(dp + 4) = (png_byte)((v >> 8) & 0xff);
+*(dp + 5) = (png_byte)(v & 0xff);
+}
+else if (a == 0)
+{
+/* background is already in screen gamma */
+*dp = (png_byte)((background->red >> 8) & 0xff);
+*(dp + 1) = (png_byte)(background->red & 0xff);
+*(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
+*(dp + 3) = (png_byte)(background->green & 0xff);
+*(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+*(dp + 5) = (png_byte)(background->blue & 0xff);
+}
+else
+{
+png_uint_16 v, w, x;
+v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+png_composite_16(w, v, a, background_1->red);
+x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
+*dp = (png_byte)((x >> 8) & 0xff);
+*(dp + 1) = (png_byte)(x & 0xff);
+v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
+png_composite_16(w, v, a, background_1->green);
+x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
+*(dp + 2) = (png_byte)((x >> 8) & 0xff);
+*(dp + 3) = (png_byte)(x & 0xff);
+v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
+png_composite_16(w, v, a, background_1->blue);
+x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
+*(dp + 4) = (png_byte)((x >> 8) & 0xff);
+*(dp + 5) = (png_byte)(x & 0xff);
+}
+}
+}
+else
+#endif
+{
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+{
+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_memcpy(dp, sp, 6);
+}
+else if (a == 0)
+{
+*dp = (png_byte)((background->red >> 8) & 0xff);
+*(dp + 1) = (png_byte)(background->red & 0xff);
+*(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
+*(dp + 3) = (png_byte)(background->green & 0xff);
+*(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+*(dp + 5) = (png_byte)(background->blue & 0xff);
+}
+else
+{
+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, background->red);
+*dp = (png_byte)((v >> 8) & 0xff);
+*(dp + 1) = (png_byte)(v & 0xff);
+png_composite_16(v, g, a, background->green);
+*(dp + 2) = (png_byte)((v >> 8) & 0xff);
+*(dp + 3) = (png_byte)(v & 0xff);
+png_composite_16(v, b, a, background->blue);
+*(dp + 4) = (png_byte)((v >> 8) & 0xff);
+*(dp + 5) = (png_byte)(v & 0xff);
+}
+}
+}
+}
+break;
+}
+}
+if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+{
+row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
+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);
+}
+}
+}
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+/* Gamma correct the image, avoiding the alpha channel.  Make sure
+* you do this after you deal with the transparency issue on grayscale
+* or RGB images. If your bit depth is 8, use gamma_table, if it
+* is 16, use gamma_16_table and gamma_shift.  Build these with
+* build_gamma_table().
+*/
+void /* PRIVATE */
+png_do_gamma(png_row_infop row_info, png_bytep row,
+png_bytep gamma_table, png_uint_16pp gamma_16_table,
+int gamma_shift)
+{
+png_bytep sp;
+png_uint_32 i;
+png_uint_32 row_width=row_info->width;
+png_debug(1, "in png_do_gamma\n");
+if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL && row_info != NULL &&
+#endif
+((row_info->bit_depth <= 8 && gamma_table != NULL) ||
+(row_info->bit_depth == 16 && gamma_16_table != NULL)))
+{
+switch (row_info->color_type)
+{
+case PNG_COLOR_TYPE_RGB:
+{
+if (row_info->bit_depth == 8)
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+*sp = gamma_table[*sp];
+sp++;
+*sp = gamma_table[*sp];
+sp++;
+*sp = gamma_table[*sp];
+sp++;
+}
+}
+else /* if (row_info->bit_depth == 16) */
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 v;
+v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 2;
+v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 2;
+v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 2;
+}
+}
+break;
+}
+case PNG_COLOR_TYPE_RGB_ALPHA:
+{
+if (row_info->bit_depth == 8)
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+*sp = gamma_table[*sp];
+sp++;
+*sp = gamma_table[*sp];
+sp++;
+*sp = gamma_table[*sp];
+sp++;
+sp++;
+}
+}
+else /* if (row_info->bit_depth == 16) */
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 2;
+v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 2;
+v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 4;
+}
+}
+break;
+}
+case PNG_COLOR_TYPE_GRAY_ALPHA:
+{
+if (row_info->bit_depth == 8)
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+*sp = gamma_table[*sp];
+sp += 2;
+}
+}
+else /* if (row_info->bit_depth == 16) */
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 4;
+}
+}
+break;
+}
+case PNG_COLOR_TYPE_GRAY:
+{
+if (row_info->bit_depth == 2)
+{
+sp = row;
+for (i = 0; i < row_width; i += 4)
+{
+int a = *sp & 0xc0;
+int b = *sp & 0x30;
+int c = *sp & 0x0c;
+int d = *sp & 0x03;
+*sp = (png_byte)(
+((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
+((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
+((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
+((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
+sp++;
+}
+}
+if (row_info->bit_depth == 4)
+{
+sp = row;
+for (i = 0; i < row_width; i += 2)
+{
+int msb = *sp & 0xf0;
+int lsb = *sp & 0x0f;
+*sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
+| (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
+sp++;
+}
+}
+else if (row_info->bit_depth == 8)
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+*sp = gamma_table[*sp];
+sp++;
+}
+}
+else if (row_info->bit_depth == 16)
+{
+sp = row;
+for (i = 0; i < row_width; i++)
+{
+png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+*sp = (png_byte)((v >> 8) & 0xff);
+*(sp + 1) = (png_byte)(v & 0xff);
+sp += 2;
+}
+}
+break;
+}
+}
+}
+}
+#endif
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+/* Expands a palette row to an RGB or RGBA row depending
+* upon whether you supply trans and num_trans.
+*/
+void /* PRIVATE */
+png_do_expand_palette(png_row_infop row_info, png_bytep row,
+png_colorp palette, png_bytep trans, int num_trans)
+{
+int shift, value;
+png_bytep sp, dp;
+png_uint_32 i;
+png_uint_32 row_width=row_info->width;
+png_debug(1, "in png_do_expand_palette\n");
+if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL && row_info != NULL &&
+#endif
+row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+{
+if (row_info->bit_depth < 8)
+{
+switch (row_info->bit_depth)
+{
+case 1:
+{
+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 = 1;
+else
+*dp = 0;
+if (shift == 7)
+{
+shift = 0;
+sp--;
+}
+else
+shift++;
+dp--;
+}
+break;
+}
+case 2:
+{
+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;
+if (shift == 6)
+{
+shift = 0;
+sp--;
+}
+else
+shift += 2;
+dp--;
+}
+break;
+}
+case 4:
+{
+sp = row + (png_size_t)((row_width - 1) >> 1);
+dp = row + (png_size_t)row_width - 1;
+shift = (int)((row_width & 0x01) << 2);
+for (i = 0; i < row_width; i++)
+{
+value = (*sp >> shift) & 0x0f;
+*dp = (png_byte)value;
+if (shift == 4)
+{
+shift = 0;
+sp--;
+}
+else
+shift += 4;
+dp--;
+}
+break;
+}
+}
+row_info->bit_depth = 8;
+row_info->pixel_depth = 8;
+row_info->rowbytes = row_width;
+}
+switch (row_info->bit_depth)
+{
+case 8:
+{
+if (trans != NULL)
+{
+sp = row + (png_size_t)row_width - 1;
+dp = row + (png_size_t)(row_width << 2) - 1;
+for (i = 0; i < row_width; i++)
+{
+if ((int)(*sp) >= num_trans)
+*dp-- = 0xff;
+else
+*dp-- = trans[*sp];
+*dp-- = palette[*sp].blue;
+*dp-- = palette[*sp].green;
+*dp-- = palette[*sp].red;
+sp--;
+}
+row_info->bit_depth = 8;
+row_info->pixel_depth = 32;
+row_info->rowbytes = row_width * 4;
+row_info->color_type = 6;
+row_info->channels = 4;
+}
+else
+{
+sp = row + (png_size_t)row_width - 1;
+dp = row + (png_size_t)(row_width * 3) - 1;
+for (i = 0; i < row_width; i++)
+{
+*dp-- = palette[*sp].blue;
+*dp-- = palette[*sp].green;
+*dp-- = palette[*sp].red;
+sp--;
+}
+row_info->bit_depth = 8;
+row_info->pixel_depth = 24;
+row_info->rowbytes = row_width * 3;
+row_info->color_type = 2;
+row_info->channels = 3;
+}
+break;
+}
+}
+}
+}
+/* If the bit depth < 8, it is expanded to 8.  Also, if the already
+* expanded transparency value is supplied, an alpha channel is built.
+*/
+void /* PRIVATE */
+png_do_expand(png_row_infop row_info, png_bytep row,
+png_color_16p trans_value)
+{
+int shift, value;
+png_bytep sp, dp;
+png_uint_32 i;
+png_uint_32 row_width=row_info->width;
+png_debug(1, "in png_do_expand\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+if (row != NULL && row_info != NULL)
+#endif
+{
+if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+{
+png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0);
+if (row_info->bit_depth < 8)
+{
+switch (row_info->bit_depth)
+{
+case 1:
+{
+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);
+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 = (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);
+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 = (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);
+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;
+}
+}
+row_info->bit_depth = 8;
+row_info->pixel_depth = 8;
+row_info->rowbytes = row_width;
+}
+if (trans_value != 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;
+for (i = 0; i < row_width; i++)
+{
+if (*sp == gray)
+*dp-- = 0;
+else
+*dp-- = 0xff;
+*dp-- = *sp--;
+}
+}
+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 (*(sp-1) == gray_high && *(sp) == gray_low)
+{
+*dp-- = 0;
+*dp-- = 0;
+}
+else
+{
+*dp-- = 0xff;
+*dp-- = 0xff;
+}
+*dp-- = *sp--;
+*dp-- = *sp--;
+}
+}
+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_value)
+{
+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) == 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 = (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 (*(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
+#if defined(PNG_READ_DITHER_SUPPORTED)
+void /* PRIVATE */
+png_do_dither(png_row_infop row_info, png_bytep row,
+png_bytep palette_lookup, png_bytep dither_lookup)
+{
+png_bytep sp, dp;
+png_uint_32 i;
+png_uint_32 row_width=row_info->width;
+png_debug(1, "in png_do_dither\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+if (row != NULL && row_info != NULL)
+#endif
+{
+if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+palette_lookup && row_info->bit_depth == 8)
+{
+int r, g, b, p;
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++)
+{
+r = *sp++;
+g = *sp++;
+b = *sp++;
+/* this looks real messy, but the compiler will reduce
+it down to a reasonable formula.  For example, with
+5 bits per color, we get:
+p = (((r >> 3) & 0x1f) << 10) |
+(((g >> 3) & 0x1f) << 5) |
+((b >> 3) & 0x1f);
+*/
+p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
+((1 << PNG_DITHER_RED_BITS) - 1)) <<
+(PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
+(((g >> (8 - PNG_DITHER_GREEN_BITS)) &
+((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
+(PNG_DITHER_BLUE_BITS)) |
+((b >> (8 - PNG_DITHER_BLUE_BITS)) &
+((1 << PNG_DITHER_BLUE_BITS) - 1));
+*dp++ = palette_lookup[p];
+}
+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);
+}
+else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+palette_lookup != NULL && row_info->bit_depth == 8)
+{
+int r, g, b, p;
+sp = row;
+dp = row;
+for (i = 0; i < row_width; i++)
+{
+r = *sp++;
+g = *sp++;
+b = *sp++;
+sp++;
+p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
+((1 << PNG_DITHER_RED_BITS) - 1)) <<
+(PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
+(((g >> (8 - PNG_DITHER_GREEN_BITS)) &
+((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
+(PNG_DITHER_BLUE_BITS)) |
+((b >> (8 - PNG_DITHER_BLUE_BITS)) &
+((1 << PNG_DITHER_BLUE_BITS) - 1));
+*dp++ = palette_lookup[p];
+}
+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);
+}
+else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+dither_lookup && row_info->bit_depth == 8)
+{
+sp = row;
+for (i = 0; i < row_width; i++, sp++)
+{
+*sp = dither_lookup[*sp];
+}
+}
+}
+}
+#endif
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+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
+* the future.  Note also how the gamma_16 tables are segmented so that
+* we don't need to allocate > 64K chunks for a full 16-bit table.
+*/
+void /* PRIVATE */
+png_build_gamma_table(png_structp png_ptr)
+{
+png_debug(1, "in png_build_gamma_table\n");
+if (png_ptr->bit_depth <= 8)
+{
+int i;
+double g;
+if (png_ptr->screen_gamma > .000001)
+g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+else
+g = 1.0;
+png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr,
+(png_uint_32)256);
+for (i = 0; i < 256; i++)
+{
+png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0,
+g) * 255.0 + .5);
+}
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY))
+{
+g = 1.0 / (png_ptr->gamma);
+png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr,
+(png_uint_32)256);
+for (i = 0; i < 256; i++)
+{
+png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0,
+g) * 255.0 + .5);
+}
+png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr,
+(png_uint_32)256);
+if(png_ptr->screen_gamma > 0.000001)
+g = 1.0 / png_ptr->screen_gamma;
+else
+g = png_ptr->gamma;   /* probably doing rgb_to_gray */
+for (i = 0; i < 256; i++)
+{
+png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
+g) * 255.0 + .5);
+}
+}
+#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+}
+else
+{
+double g;
+int i, j, shift, num;
+int sig_bit;
+png_uint_32 ig;
+if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+{
+sig_bit = (int)png_ptr->sig_bit.red;
+if ((int)png_ptr->sig_bit.green > sig_bit)
+sig_bit = png_ptr->sig_bit.green;
+if ((int)png_ptr->sig_bit.blue > sig_bit)
+sig_bit = png_ptr->sig_bit.blue;
+}
+else
+{
+sig_bit = (int)png_ptr->sig_bit.gray;
+}
+if (sig_bit > 0)
+shift = 16 - sig_bit;
+else
+shift = 0;
+if (png_ptr->transformations & PNG_16_TO_8)
+{
+if (shift < (16 - PNG_MAX_GAMMA_8))
+shift = (16 - PNG_MAX_GAMMA_8);
+}
+if (shift > 8)
+shift = 8;
+if (shift < 0)
+shift = 0;
+png_ptr->gamma_shift = (png_byte)shift;
+num = (1 << (8 - shift));
+if (png_ptr->screen_gamma > .000001)
+g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+else
+g = 1.0;
+png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr,
+(png_uint_32)(num * png_sizeof (png_uint_16p)));
+if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
+{
+double fin, fout;
+png_uint_32 last, max;
+for (i = 0; i < num; i++)
+{
+png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
+(png_uint_32)(256 * png_sizeof (png_uint_16)));
+}
+g = 1.0 / g;
+last = 0;
+for (i = 0; i < 256; i++)
+{
+fout = ((double)i + 0.5) / 256.0;
+fin = pow(fout, g);
+max = (png_uint_32)(fin * (double)((png_uint_32)num << 8));
+while (last <= max)
+{
+png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
+[(int)(last >> (8 - shift))] = (png_uint_16)(
+(png_uint_16)i | ((png_uint_16)i << 8));
+last++;
+}
+}
+while (last < ((png_uint_32)num << 8))
+{
+png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
+[(int)(last >> (8 - shift))] = (png_uint_16)65535L;
+last++;
+}
+}
+else
+{
+for (i = 0; i < num; i++)
+{
+png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
+(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++)
+{
+png_ptr->gamma_16_table[i][j] =
+(png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+65535.0, g) * 65535.0 + .5);
+}
+}
+}
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
+{
+g = 1.0 / (png_ptr->gamma);
+png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr,
+(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,
+(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++)
+{
+png_ptr->gamma_16_to_1[i][j] =
+(png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+65535.0, g) * 65535.0 + .5);
+}
+}
+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_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,
+(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++)
+{
+png_ptr->gamma_16_from_1[i][j] =
+(png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+65535.0, g) * 65535.0 + .5);
+}
+}
+}
+#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+}
+}
+#endif
+/* To do: install integer version of png_build_gamma_table here */
+#endif
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* undoes intrapixel differencing  */
+void /* PRIVATE */
+png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+{
+png_debug(1, "in png_do_read_intrapixel\n");
+if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+row != NULL && row_info != NULL &&
+#endif
+(row_info->color_type & PNG_COLOR_MASK_COLOR))
+{
+int bytes_per_pixel;
+png_uint_32 row_width = row_info->width;
+if (row_info->bit_depth == 8)
+{
+png_bytep rp;
+png_uint_32 i;
+if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+bytes_per_pixel = 3;
+else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+bytes_per_pixel = 4;
+else
+return;
+for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+{
+*(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff);
+*(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff);
+}
+}
+else if (row_info->bit_depth == 16)
+{
+png_bytep rp;
+png_uint_32 i;
+if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+bytes_per_pixel = 6;
+else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+bytes_per_pixel = 8;
+else
+return;
+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);
+*(rp  ) = (png_byte)((red >> 8) & 0xff);
+*(rp+1) = (png_byte)(red & 0xff);
+*(rp+4) = (png_byte)((blue >> 8) & 0xff);
+*(rp+5) = (png_byte)(blue & 0xff);
+}
+}
+}
+}
+#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED */

Mercurial > fife-parpg

comparison ext/libpng-1.2.29/pngrtran.c @ 89:fa33cda75471