zero_samples=0;   png_set_write_user_transform_fn(write_ptr, count_zero_samples);#endif#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)#  ifndef PNG_HANDLE_CHUNK_ALWAYS#    define PNG_HANDLE_CHUNK_ALWAYS       3#  endif   png_set_keep_unknown_chunks(read_ptr, PNG_HANDLE_CHUNK_ALWAYS,      png_bytep_NULL, 0);#endif#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)#  ifndef PNG_HANDLE_CHUNK_IF_SAFE#    define PNG_HANDLE_CHUNK_IF_SAFE      2#  endif   png_set_keep_unknown_chunks(write_ptr, PNG_HANDLE_CHUNK_IF_SAFE,      png_bytep_NULL, 0);#endif   png_debug(0, "Reading info struct\n");   png_read_info(read_ptr, read_info_ptr);   png_debug(0, "Transferring info struct\n");   {      int interlace_type, compression_type, filter_type;      if (png_get_IHDR(read_ptr, read_info_ptr, &width, &height, &bit_depth,          &color_type, &interlace_type, &compression_type, &filter_type))      {         png_set_IHDR(write_ptr, write_info_ptr, width, height, bit_depth,#if defined(PNG_WRITE_INTERLACING_SUPPORTED)            color_type, interlace_type, compression_type, filter_type);#else            color_type, PNG_INTERLACE_NONE, compression_type, filter_type);#endif      }   }#if defined(PNG_FIXED_POINT_SUPPORTED)#if defined(PNG_cHRM_SUPPORTED)   {      png_fixed_point white_x, white_y, red_x, red_y, green_x, green_y, blue_x,         blue_y;      if (png_get_cHRM_fixed(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,         &red_y, &green_x, &green_y, &blue_x, &blue_y))      {         png_set_cHRM_fixed(write_ptr, write_info_ptr, white_x, white_y, red_x,            red_y, green_x, green_y, blue_x, blue_y);      }   }#endif#if defined(PNG_gAMA_SUPPORTED)   {      png_fixed_point gamma;      if (png_get_gAMA_fixed(read_ptr, read_info_ptr, &gamma))      {         png_set_gAMA_fixed(write_ptr, write_info_ptr, gamma);      }   }#endif#else /* Use floating point versions */#if defined(PNG_FLOATING_POINT_SUPPORTED)#if defined(PNG_cHRM_SUPPORTED)   {      double white_x, white_y, red_x, red_y, green_x, green_y, blue_x,         blue_y;      if (png_get_cHRM(read_ptr, read_info_ptr, &white_x, &white_y, &red_x,         &red_y, &green_x, &green_y, &blue_x, &blue_y))      {         png_set_cHRM(write_ptr, write_info_ptr, white_x, white_y, red_x,            red_y, green_x, green_y, blue_x, blue_y);      }   }#endif#if defined(PNG_gAMA_SUPPORTED)   {      double gamma;      if (png_get_gAMA(read_ptr, read_info_ptr, &gamma))      {         png_set_gAMA(write_ptr, write_info_ptr, gamma);      }   }#endif#endif /* floating point */#endif /* fixed point */#if defined(PNG_iCCP_SUPPORTED)   {      png_charp name;      png_charp profile;      png_uint_32 proflen;      int compression_type;      if (png_get_iCCP(read_ptr, read_info_ptr, &name, &compression_type,                      &profile, &proflen))      {         png_set_iCCP(write_ptr, write_info_ptr, name, compression_type,                      profile, proflen);      }   }#endif#if defined(PNG_sRGB_SUPPORTED)   {      int intent;      if (png_get_sRGB(read_ptr, read_info_ptr, &intent))      {         png_set_sRGB(write_ptr, write_info_ptr, intent);      }   }#endif   {      png_colorp palette;      int num_palette;      if (png_get_PLTE(read_ptr, read_info_ptr, &palette, &num_palette))      {         png_set_PLTE(write_ptr, write_info_ptr, palette, num_palette);      }   }#if defined(PNG_bKGD_SUPPORTED)   {      png_color_16p background;      if (png_get_bKGD(read_ptr, read_info_ptr, &background))      {         png_set_bKGD(write_ptr, write_info_ptr, background);      }   }#endif#if defined(PNG_hIST_SUPPORTED)   {      png_uint_16p hist;      if (png_get_hIST(read_ptr, read_info_ptr, &hist))      {         png_set_hIST(write_ptr, write_info_ptr, hist);      }   }#endif#if defined(PNG_oFFs_SUPPORTED)   {      png_int_32 offset_x, offset_y;      int unit_type;      if (png_get_oFFs(read_ptr, read_info_ptr,&offset_x,&offset_y,&unit_type))      {         png_set_oFFs(write_ptr, write_info_ptr, offset_x, offset_y, unit_type);      }   }#endif#if defined(PNG_pCAL_SUPPORTED)   {      png_charp purpose, units;      png_charpp params;      png_int_32 X0, X1;      int type, nparams;      if (png_get_pCAL(read_ptr, read_info_ptr, &purpose, &X0, &X1, &type,         &nparams, &units, &params))      {         png_set_pCAL(write_ptr, write_info_ptr, purpose, X0, X1, type,            nparams, units, params);      }   }#endif#if defined(PNG_pHYs_SUPPORTED)   {      png_uint_32 res_x, res_y;      int unit_type;      if (png_get_pHYs(read_ptr, read_info_ptr, &res_x, &res_y, &unit_type))      {         png_set_pHYs(write_ptr, write_info_ptr, res_x, res_y, unit_type);      }   }#endif#if defined(PNG_sBIT_SUPPORTED)   {      png_color_8p sig_bit;      if (png_get_sBIT(read_ptr, read_info_ptr, &sig_bit))      {         png_set_sBIT(write_ptr, write_info_ptr, sig_bit);      }   }#endif#if defined(PNG_sCAL_SUPPORTED)#ifdef PNG_FLOATING_POINT_SUPPORTED   {      int unit;      double scal_width, scal_height;      if (png_get_sCAL(read_ptr, read_info_ptr, &unit, &scal_width,         &scal_height))      {         png_set_sCAL(write_ptr, write_info_ptr, unit, scal_width, scal_height);      }   }#else#ifdef PNG_FIXED_POINT_SUPPORTED   {      int unit;      png_charp scal_width, scal_height;      if (png_get_sCAL_s(read_ptr, read_info_ptr, &unit, &scal_width,          &scal_height))      {         png_set_sCAL_s(write_ptr, write_info_ptr, unit, scal_width, scal_height);      }   }#endif#endif#endif#if defined(PNG_TEXT_SUPPORTED)   {      png_textp text_ptr;      int num_text;      if (png_get_text(read_ptr, read_info_ptr, &text_ptr, &num_text) > 0)      {         png_debug1(0, "Handling %d iTXt/tEXt/zTXt chunks\n", num_text);         png_set_text(write_ptr, write_info_ptr, text_ptr, num_text);      }   }#endif#if defined(PNG_tIME_SUPPORTED)   {      png_timep mod_time;      if (png_get_tIME(read_ptr, read_info_ptr, &mod_time))      {         png_set_tIME(write_ptr, write_info_ptr, mod_time);#if defined(PNG_TIME_RFC1123_SUPPORTED)         /* we have to use png_strcpy instead of "=" because the string            pointed to by png_convert_to_rfc1123() gets free'ed before            we use it */         png_strcpy(tIME_string,png_convert_to_rfc1123(read_ptr, mod_time));         tIME_chunk_present++;#endif /* PNG_TIME_RFC1123_SUPPORTED */      }   }#endif#if defined(PNG_tRNS_SUPPORTED)   {      png_bytep trans;      int num_trans;      png_color_16p trans_values;      if (png_get_tRNS(read_ptr, read_info_ptr, &trans, &num_trans,         &trans_values))      {         png_set_tRNS(write_ptr, write_info_ptr, trans, num_trans,            trans_values);      }   }#endif#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)   {      png_unknown_chunkp unknowns;      int num_unknowns = (int)png_get_unknown_chunks(read_ptr, read_info_ptr,         &unknowns);      if (num_unknowns)      {         png_size_t i;         png_set_unknown_chunks(write_ptr, write_info_ptr, unknowns,           num_unknowns);         /* copy the locations from the read_info_ptr.  The automatically            generated locations in write_info_ptr are wrong because we            haven't written anything yet */         for (i = 0; i < (png_size_t)num_unknowns; i++)           png_set_unknown_chunk_location(write_ptr, write_info_ptr, i,             unknowns[i].location);      }   }#endif#ifdef PNG_WRITE_SUPPORTED   png_debug(0, "\nWriting info struct\n");/* If we wanted, we could write info in two steps:   png_write_info_before_PLTE(write_ptr, write_info_ptr); */   png_write_info(write_ptr, write_info_ptr);#endif#ifdef SINGLE_ROWBUF_ALLOC   png_debug(0, "\nAllocating row buffer...");   row_buf = (png_bytep)png_malloc(read_ptr,      png_get_rowbytes(read_ptr, read_info_ptr));   png_debug1(0, "0x%08lx\n\n", (unsigned long)row_buf);#endif /* SINGLE_ROWBUF_ALLOC */   png_debug(0, "Writing row data\n");#if defined(PNG_READ_INTERLACING_SUPPORTED) || \  defined(PNG_WRITE_INTERLACING_SUPPORTED)   num_pass = png_set_interlace_handling(read_ptr);#  ifdef PNG_WRITE_SUPPORTED   png_set_interlace_handling(write_ptr);#  endif#else   num_pass=1;#endif#ifdef PNGTEST_TIMING   t_stop = (float)clock();   t_misc += (t_stop - t_start);   t_start = t_stop;#endif   for (pass = 0; pass < num_pass; pass++)   {      png_debug1(0, "Writing row data for pass %d\n",pass);      for (y = 0; y < height; y++)      {#ifndef SINGLE_ROWBUF_ALLOC         png_debug2(0, "\nAllocating row buffer (pass %d, y = %ld)...", pass,y);         row_buf = (png_bytep)png_malloc(read_ptr,            png_get_rowbytes(read_ptr, read_info_ptr));         png_debug2(0, "0x%08lx (%ld bytes)\n", (unsigned long)row_buf,            png_get_rowbytes(read_ptr, read_info_ptr));#endif /* !SINGLE_ROWBUF_ALLOC */         png_read_rows(read_ptr, (png_bytepp)&row_buf, png_bytepp_NULL, 1);#ifdef PNG_WRITE_SUPPORTED#ifdef PNGTEST_TIMING         t_stop = (float)clock();         t_decode += (t_stop - t_start);         t_start = t_stop;#endif         png_write_rows(write_ptr, (png_bytepp)&row_buf, 1);#ifdef PNGTEST_TIMING         t_stop = (float)clock();         t_encode += (t_stop - t_start);         t_start = t_stop;#endif#endif /* PNG_WRITE_SUPPORTED */#ifndef SINGLE_ROWBUF_ALLOC         png_debug2(0, "Freeing row buffer (pass %d, y = %ld)\n\n", pass, y);         png_free(read_ptr, row_buf);#endif /* !SINGLE_ROWBUF_ALLOC */      }   }#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)   png_free_data(read_ptr, read_info_ptr, PNG_FREE_UNKN, -1);#endif#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)   png_free_data(write_ptr, write_info_ptr, PNG_FREE_UNKN, -1);#endif   png_debug(0, "Reading and writing end_info data\n");   png_read_end(read_ptr, end_info_ptr);#if defined(PNG_TEXT_SUPPORTED)   {      png_textp text_ptr;      int num_text;      if (png_get_text(read_ptr, end_info_ptr, &text_ptr, &num_text) > 0)      {         png_debug1(0, "Handling %d iTXt/tEXt/zTXt chunks\n", num_text);         png_set_text(write_ptr, write_end_info_ptr, text_ptr, num_text);      }   }#endif#if defined(PNG_tIME_SUPPORTED)   {      png_timep mod_time;      if (png_get_tIME(read_ptr, end_info_ptr, &mod_time))      {         png_set_tIME(write_ptr, write_end_info_ptr, mod_time);#if defined(PNG_TIME_RFC1123_SUPPORTED)         /* we have to use png_strcpy instead of "=" because the string            pointed to by png_convert_to_rfc1123() gets free'ed before            we use it */         png_strcpy(tIME_string,png_convert_to_rfc1123(read_ptr, mod_time));         tIME_chunk_present++;#endif /* PNG_TIME_RFC1123_SUPPORTED */      }   }#endif#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)   {      png_unknown_chunkp unknowns;      int num_unknowns;      num_unknowns = (int)png_get_unknown_chunks(read_ptr, end_info_ptr,         &unknowns);