if (png_ptr != NULL)   {      png_write_destroy(png_ptr);#ifdef PNG_USER_MEM_SUPPORTED      png_destroy_struct_2((png_voidp)png_ptr, free_fn);#else      png_destroy_struct((png_voidp)png_ptr);#endif      *png_ptr_ptr = (png_structp)NULL;   }}/* Free any memory used in png_ptr struct (old method) */void PNGAPIpng_write_destroy(png_structp png_ptr){#ifdef PNG_SETJMP_SUPPORTED   jmp_buf tmp_jmp; /* save jump buffer */#endif   png_error_ptr error_fn;   png_error_ptr warning_fn;   png_voidp error_ptr;#ifdef PNG_USER_MEM_SUPPORTED   png_free_ptr free_fn;#endif   png_debug(1, "in png_write_destroy\n");   /* free any memory zlib uses */   deflateEnd(&png_ptr->zstream);   /* free our memory.  png_free checks NULL for us. */   png_free(png_ptr, png_ptr->zbuf);   png_free(png_ptr, png_ptr->row_buf);   png_free(png_ptr, png_ptr->prev_row);   png_free(png_ptr, png_ptr->sub_row);   png_free(png_ptr, png_ptr->up_row);   png_free(png_ptr, png_ptr->avg_row);   png_free(png_ptr, png_ptr->paeth_row);#if defined(PNG_TIME_RFC1123_SUPPORTED)   png_free(png_ptr, png_ptr->time_buffer);#endif#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)   png_free(png_ptr, png_ptr->prev_filters);   png_free(png_ptr, png_ptr->filter_weights);   png_free(png_ptr, png_ptr->inv_filter_weights);   png_free(png_ptr, png_ptr->filter_costs);   png_free(png_ptr, png_ptr->inv_filter_costs);#endif#ifdef PNG_SETJMP_SUPPORTED   /* reset structure */   png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));#endif   error_fn = png_ptr->error_fn;   warning_fn = png_ptr->warning_fn;   error_ptr = png_ptr->error_ptr;#ifdef PNG_USER_MEM_SUPPORTED   free_fn = png_ptr->free_fn;#endif   png_memset(png_ptr, 0, sizeof (png_struct));   png_ptr->error_fn = error_fn;   png_ptr->warning_fn = warning_fn;   png_ptr->error_ptr = error_ptr;#ifdef PNG_USER_MEM_SUPPORTED   png_ptr->free_fn = free_fn;#endif#ifdef PNG_SETJMP_SUPPORTED   png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));#endif}/* Allow the application to select one or more row filters to use. */void PNGAPIpng_set_filter(png_structp png_ptr, int method, int filters){   png_debug(1, "in png_set_filter\n");#if defined(PNG_MNG_FEATURES_SUPPORTED)   if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&      (method == PNG_INTRAPIXEL_DIFFERENCING))         method = PNG_FILTER_TYPE_BASE;#endif   if (method == PNG_FILTER_TYPE_BASE)   {      switch (filters & (PNG_ALL_FILTERS | 0x07))      {         case 5:         case 6:         case 7: png_warning(png_ptr, "Unknown row filter for method 0");         case PNG_FILTER_VALUE_NONE:  png_ptr->do_filter=PNG_FILTER_NONE; break;         case PNG_FILTER_VALUE_SUB:   png_ptr->do_filter=PNG_FILTER_SUB;  break;         case PNG_FILTER_VALUE_UP:    png_ptr->do_filter=PNG_FILTER_UP;   break;         case PNG_FILTER_VALUE_AVG:   png_ptr->do_filter=PNG_FILTER_AVG;  break;         case PNG_FILTER_VALUE_PAETH: png_ptr->do_filter=PNG_FILTER_PAETH;break;         default: png_ptr->do_filter = (png_byte)filters; break;      }      /* If we have allocated the row_buf, this means we have already started       * with the image and we should have allocated all of the filter buffers       * that have been selected.  If prev_row isn't already allocated, then       * it is too late to start using the filters that need it, since we       * will be missing the data in the previous row.  If an application       * wants to start and stop using particular filters during compression,       * it should start out with all of the filters, and then add and       * remove them after the start of compression.       */      if (png_ptr->row_buf != NULL)      {         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)         {            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,              (png_ptr->rowbytes + 1));            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;         }         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)         {            if (png_ptr->prev_row == NULL)            {               png_warning(png_ptr, "Can't add Up filter after starting");               png_ptr->do_filter &= ~PNG_FILTER_UP;            }            else            {               png_ptr->up_row = (png_bytep)png_malloc(png_ptr,                  (png_ptr->rowbytes + 1));               png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;            }         }         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)         {            if (png_ptr->prev_row == NULL)            {               png_warning(png_ptr, "Can't add Average filter after starting");               png_ptr->do_filter &= ~PNG_FILTER_AVG;            }            else            {               png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,                  (png_ptr->rowbytes + 1));               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;            }         }         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&             png_ptr->paeth_row == NULL)         {            if (png_ptr->prev_row == NULL)            {               png_warning(png_ptr, "Can't add Paeth filter after starting");               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);            }            else            {               png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,                  (png_ptr->rowbytes + 1));               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;            }         }         if (png_ptr->do_filter == PNG_NO_FILTERS)            png_ptr->do_filter = PNG_FILTER_NONE;      }   }   else      png_error(png_ptr, "Unknown custom filter method");}/* This allows us to influence the way in which libpng chooses the "best" * filter for the current scanline.  While the "minimum-sum-of-absolute- * differences metric is relatively fast and effective, there is some * question as to whether it can be improved upon by trying to keep the * filtered data going to zlib more consistent, hopefully resulting in * better compression. */#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)      /* GRR 970116 */void PNGAPIpng_set_filter_heuristics(png_structp png_ptr, int heuristic_method,   int num_weights, png_doublep filter_weights,   png_doublep filter_costs){   int i;   png_debug(1, "in png_set_filter_heuristics\n");   if (heuristic_method >= PNG_FILTER_HEURISTIC_LAST)   {      png_warning(png_ptr, "Unknown filter heuristic method");      return;   }   if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT)   {      heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;   }   if (num_weights < 0 || filter_weights == NULL ||      heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)   {      num_weights = 0;   }   png_ptr->num_prev_filters = (png_byte)num_weights;   png_ptr->heuristic_method = (png_byte)heuristic_method;   if (num_weights > 0)   {      if (png_ptr->prev_filters == NULL)      {         png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,            (png_uint_32)(sizeof(png_byte) * num_weights));         /* To make sure that the weighting starts out fairly */         for (i = 0; i < num_weights; i++)         {            png_ptr->prev_filters[i] = 255;         }      }      if (png_ptr->filter_weights == NULL)      {         png_ptr->filter_weights = (png_uint_16p) png_malloc(png_ptr,            (png_uint_32)(sizeof(png_uint_16) * num_weights));         png_ptr->inv_filter_weights = (png_uint_16p) png_malloc(png_ptr,            (png_uint_32)(sizeof(png_uint_16) * num_weights));         for (i = 0; i < num_weights; i++)         {            png_ptr->inv_filter_weights[i] =            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;         }      }      for (i = 0; i < num_weights; i++)      {         if (filter_weights[i] < 0.0)         {            png_ptr->inv_filter_weights[i] =            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;         }         else         {            png_ptr->inv_filter_weights[i] =               (png_uint_16)((double)PNG_WEIGHT_FACTOR*filter_weights[i]+0.5);            png_ptr->filter_weights[i] =               (png_uint_16)((double)PNG_WEIGHT_FACTOR/filter_weights[i]+0.5);         }      }   }   /* If, in the future, there are other filter methods, this would    * need to be based on png_ptr->filter.    */   if (png_ptr->filter_costs == NULL)   {      png_ptr->filter_costs = (png_uint_16p) png_malloc(png_ptr,         (png_uint_32)(sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));      png_ptr->inv_filter_costs = (png_uint_16p) png_malloc(png_ptr,         (png_uint_32)(sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)      {         png_ptr->inv_filter_costs[i] =         png_ptr->filter_costs[i] = PNG_COST_FACTOR;      }   }   /* Here is where we set the relative costs of the different filters.  We    * should take the desired compression level into account when setting    * the costs, so that Paeth, for instance, has a high relative cost at low    * compression levels, while it has a lower relative cost at higher    * compression settings.  The filter types are in order of increasing    * relative cost, so it would be possible to do this with an algorithm.    */   for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)   {      if (filter_costs == NULL || filter_costs[i] < 0.0)      {         png_ptr->inv_filter_costs[i] =         png_ptr->filter_costs[i] = PNG_COST_FACTOR;      }      else if (filter_costs[i] >= 1.0)      {         png_ptr->inv_filter_costs[i] =            (png_uint_16)((double)PNG_COST_FACTOR / filter_costs[i] + 0.5);         png_ptr->filter_costs[i] =            (png_uint_16)((double)PNG_COST_FACTOR * filter_costs[i] + 0.5);      }   }}#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */void PNGAPIpng_set_compression_level(png_structp png_ptr, int level){   png_debug(1, "in png_set_compression_level\n");   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;   png_ptr->zlib_level = level;}void PNGAPIpng_set_compression_mem_level(png_structp png_ptr, int mem_level){   png_debug(1, "in png_set_compression_mem_level\n");   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;   png_ptr->zlib_mem_level = mem_level;}void PNGAPIpng_set_compression_strategy(png_structp png_ptr, int strategy){   png_debug(1, "in png_set_compression_strategy\n");   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;   png_ptr->zlib_strategy = strategy;}void PNGAPIpng_set_compression_window_bits(png_structp png_ptr, int window_bits){   if (window_bits > 15)      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");   else if (window_bits < 8)      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");#ifndef WBITS_8_OK   /* avoid libpng bug with 256-byte windows */   if (window_bits == 8)     {       png_warning(png_ptr, "Compression window is being reset to 512");       window_bits=9;     }#endif   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;   png_ptr->zlib_window_bits = window_bits;}void PNGAPIpng_set_compression_method(png_structp png_ptr, int method){   png_debug(1, "in png_set_compression_method\n");   if (method != 8)      png_warning(png_ptr, "Only compression method 8 is supported by PNG");   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;   png_ptr->zlib_method = method;}void PNGAPIpng_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn){   png_ptr->write_row_fn = write_row_fn;}#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)void PNGAPIpng_set_write_user_transform_fn(png_structp png_ptr, png_user_transform_ptr   write_user_transform_fn){   png_debug(1, "in png_set_write_user_transform_fn\n");   png_ptr->transformations |= PNG_USER_TRANSFORM;   png_ptr->write_user_transform_fn = write_user_transform_fn;}#endif#if defined(PNG_INFO_IMAGE_SUPPORTED)void PNGAPIpng_write_png(png_structp png_ptr, png_infop info_ptr,              int transforms, voidp params){#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)   /* invert the alpha channel from opacity to transparency */   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)       png_set_invert_alpha(png_ptr);#endif   /* Write the file header information. */   png_write_info(png_ptr, info_ptr);   /* ------ these transformations don't touch the info structure ------- */#if defined(PNG_WRITE_INVERT_SUPPORTED)   /* invert monochrome pixels */   if (transforms & PNG_TRANSFORM_INVERT_MONO)       png_set_invert_mono(png_ptr);#endif#if defined(PNG_WRITE_SHIFT_SUPPORTED)   /* Shift the pixels up to a legal bit depth and fill in    * as appropriate to correctly scale the image.    */   if ((transforms & PNG_TRANSFORM_SHIFT)               && (info_ptr->valid & PNG_INFO_sBIT))       png_set_shift(png_ptr, &info_ptr->sig_bit);#endif#if defined(PNG_WRITE_PACK_SUPPORTED)   /* pack pixels into bytes */   if (transforms & PNG_TRANSFORM_PACKING)       png_set_packing(png_ptr);#endif#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)   /* swap location of alpha bytes from ARGB to RGBA */   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)       png_set_swap_alpha(png_ptr);#endif#if defined(PNG_WRITE_FILLER_SUPPORTED)   /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into    * RGB (4 channels -> 3 channels). The second parameter is not used.    */   if (transforms & PNG_TRANSFORM_STRIP_FILLER)       png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);#endif#if defined(PNG_WRITE_BGR_SUPPORTED)   /* flip BGR pixels to RGB */   if (transforms & PNG_TRANSFORM_BGR)       png_set_bgr(png_ptr);#endif#if defined(PNG_WRITE_SWAP_SUPPORTED)   /* swap bytes of 16-bit files to most significant byte first */   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)       png_set_swap(png_ptr);#endif#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)   /* swap bits of 1, 2, 4 bit packed pixel formats */   if (transforms & PNG_TRANSFORM_PACKSWAP)       png_set_packswap(png_ptr);#endif   /* ----------------------- end of transformations ------------------- */   /* write the bits */   if (info_ptr->valid & PNG_INFO_IDAT)       png_write_image(png_ptr, info_ptr->row_pointers);   /* It is REQUIRED to call this to finish writing the rest of the file */   png_write_end(png_ptr, info_ptr);   if(transforms == 0 || params == (voidp)NULL)      /* quiet compiler warnings */ return;}#endif