+
−
/* pngwutil.c - utilities to write a PNG file+
−
 *+
−
 * Last changed in libpng 1.2.40 [September 10, 2009]+
−
 * Copyright (c) 1998-2009 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 code is released under the libpng license.+
−
 * For conditions of distribution and use, see the disclaimer+
−
 * and license in png.h+
−
 */+
−
+
−
#define PNG_INTERNAL+
−
#include "png.h"+
−
#ifdef PNG_WRITE_SUPPORTED+
−
+
−
/* Place a 32-bit number into a buffer in PNG byte order.  We work+
−
 * with unsigned numbers for convenience, although one supported+
−
 * ancillary chunk uses signed (two's complement) numbers.+
−
 */+
−
void PNGAPI+
−
png_save_uint_32(png_bytep buf, png_uint_32 i)+
−
{+
−
   buf[0] = (png_byte)((i >> 24) & 0xff);+
−
   buf[1] = (png_byte)((i >> 16) & 0xff);+
−
   buf[2] = (png_byte)((i >> 8) & 0xff);+
−
   buf[3] = (png_byte)(i & 0xff);+
−
}+
−
+
−
/* The png_save_int_32 function assumes integers are stored in two's+
−
 * complement format.  If this isn't the case, then this routine needs to+
−
 * be modified to write data in two's complement format.+
−
 */+
−
void PNGAPI+
−
png_save_int_32(png_bytep buf, png_int_32 i)+
−
{+
−
   buf[0] = (png_byte)((i >> 24) & 0xff);+
−
   buf[1] = (png_byte)((i >> 16) & 0xff);+
−
   buf[2] = (png_byte)((i >> 8) & 0xff);+
−
   buf[3] = (png_byte)(i & 0xff);+
−
}+
−
+
−
/* Place a 16-bit number into a buffer in PNG byte order.+
−
 * The parameter is declared unsigned int, not png_uint_16,+
−
 * just to avoid potential problems on pre-ANSI C compilers.+
−
 */+
−
void PNGAPI+
−
png_save_uint_16(png_bytep buf, unsigned int i)+
−
{+
−
   buf[0] = (png_byte)((i >> 8) & 0xff);+
−
   buf[1] = (png_byte)(i & 0xff);+
−
}+
−
+
−
/* Simple function to write the signature.  If we have already written+
−
 * the magic bytes of the signature, or more likely, the PNG stream is+
−
 * being embedded into another stream and doesn't need its own signature,+
−
 * we should call png_set_sig_bytes() to tell libpng how many of the+
−
 * bytes have already been written.+
−
 */+
−
void /* PRIVATE */+
−
png_write_sig(png_structp png_ptr)+
−
{+
−
   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};+
−
+
−
   /* Write the rest of the 8 byte signature */+
−
   png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],+
−
      (png_size_t)(8 - png_ptr->sig_bytes));+
−
   if (png_ptr->sig_bytes < 3)+
−
      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;+
−
}+
−
+
−
/* Write a PNG chunk all at once.  The type is an array of ASCII characters+
−
 * representing the chunk name.  The array must be at least 4 bytes in+
−
 * length, and does not need to be null terminated.  To be safe, pass the+
−
 * pre-defined chunk names here, and if you need a new one, define it+
−
 * where the others are defined.  The length is the length of the data.+
−
 * All the data must be present.  If that is not possible, use the+
−
 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()+
−
 * functions instead.+
−
 */+
−
void PNGAPI+
−
png_write_chunk(png_structp png_ptr, png_bytep chunk_name,+
−
   png_bytep data, png_size_t length)+
−
{+
−
   if (png_ptr == NULL)+
−
      return;+
−
   png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);+
−
   png_write_chunk_data(png_ptr, data, (png_size_t)length);+
−
   png_write_chunk_end(png_ptr);+
−
}+
−
+
−
/* Write the start of a PNG chunk.  The type is the chunk type.+
−
 * The total_length is the sum of the lengths of all the data you will be+
−
 * passing in png_write_chunk_data().+
−
 */+
−
void PNGAPI+
−
png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,+
−
   png_uint_32 length)+
−
{+
−
   png_byte buf[8];+
−
+
−
   png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,+
−
      (unsigned long)length);+
−
+
−
   if (png_ptr == NULL)+
−
      return;+
−
+
−
   /* Write the length and the chunk name */+
−
   png_save_uint_32(buf, length);+
−
   png_memcpy(buf + 4, chunk_name, 4);+
−
   png_write_data(png_ptr, buf, (png_size_t)8);+
−
   /* Put the chunk name into png_ptr->chunk_name */+
−
   png_memcpy(png_ptr->chunk_name, chunk_name, 4);+
−
   /* Reset the crc and run it over the chunk name */+
−
   png_reset_crc(png_ptr);+
−
   png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);+
−
}+
−
+
−
/* Write the data of a PNG chunk started with png_write_chunk_start().+
−
 * Note that multiple calls to this function are allowed, and that the+
−
 * sum of the lengths from these calls *must* add up to the total_length+
−
 * given to png_write_chunk_start().+
−
 */+
−
void PNGAPI+
−
png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)+
−
{+
−
   /* Write the data, and run the CRC over it */+
−
   if (png_ptr == NULL)+
−
      return;+
−
   if (data != NULL && length > 0)+
−
   {+
−
      png_write_data(png_ptr, data, length);+
−
      /* Update the CRC after writing the data,+
−
       * in case that the user I/O routine alters it.+
−
       */+
−
      png_calculate_crc(png_ptr, data, length);+
−
   }+
−
}+
−
+
−
/* Finish a chunk started with png_write_chunk_start(). */+
−
void PNGAPI+
−
png_write_chunk_end(png_structp png_ptr)+
−
{+
−
   png_byte buf[4];+
−
+
−
   if (png_ptr == NULL) return;+
−
+
−
   /* Write the crc in a single operation */+
−
   png_save_uint_32(buf, png_ptr->crc);+
−
+
−
   png_write_data(png_ptr, buf, (png_size_t)4);+
−
}+
−
+
−
#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)+
−
/* This pair of functions encapsulates the operation of (a) compressing a+
−
 * text string, and (b) issuing it later as a series of chunk data writes.+
−
 * The compression_state structure is shared context for these functions+
−
 * set up by the caller in order to make the whole mess thread-safe.+
−
 */+
−
+
−
typedef struct+
−
{+
−
   char *input;   /* The uncompressed input data */+
−
   int input_len;   /* Its length */+
−
   int num_output_ptr; /* Number of output pointers used */+
−
   int max_output_ptr; /* Size of output_ptr */+
−
   png_charpp output_ptr; /* Array of pointers to output */+
−
} compression_state;+
−
+
−
/* Compress given text into storage in the png_ptr structure */+
−
static int /* PRIVATE */+
−
png_text_compress(png_structp png_ptr,+
−
        png_charp text, png_size_t text_len, int compression,+
−
        compression_state *comp)+
−
{+
−
   int ret;+
−
+
−
   comp->num_output_ptr = 0;+
−
   comp->max_output_ptr = 0;+
−
   comp->output_ptr = NULL;+
−
   comp->input = NULL;+
−
   comp->input_len = 0;+
−
+
−
   /* We may just want to pass the text right through */+
−
   if (compression == PNG_TEXT_COMPRESSION_NONE)+
−
   {+
−
       comp->input = text;+
−
       comp->input_len = text_len;+
−
       return((int)text_len);+
−
   }+
−
+
−
   if (compression >= PNG_TEXT_COMPRESSION_LAST)+
−
   {+
−
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)+
−
      char msg[50];+
−
      png_snprintf(msg, 50, "Unknown compression type %d", compression);+
−
      png_warning(png_ptr, msg);+
−
#else+
−
      png_warning(png_ptr, "Unknown compression type");+
−
#endif+
−
   }+
−
+
−
   /* We can't write the chunk until we find out how much data we have,+
−
    * which means we need to run the compressor first and save the+
−
    * output.  This shouldn't be a problem, as the vast majority of+
−
    * comments should be reasonable, but we will set up an array of+
−
    * malloc'd pointers to be sure.+
−
    *+
−
    * If we knew the application was well behaved, we could simplify this+
−
    * greatly by assuming we can always malloc an output buffer large+
−
    * enough to hold the compressed text ((1001 * text_len / 1000) + 12)+
−
    * and malloc this directly.  The only time this would be a bad idea is+
−
    * if we can't malloc more than 64K and we have 64K of random input+
−
    * data, or if the input string is incredibly large (although this+
−
    * wouldn't cause a failure, just a slowdown due to swapping).+
−
    */+
−
+
−
   /* Set up the compression buffers */+
−
   png_ptr->zstream.avail_in = (uInt)text_len;+
−
   png_ptr->zstream.next_in = (Bytef *)text;+
−
   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;+
−
   png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;+
−
+
−
   /* This is the same compression loop as in png_write_row() */+
−
   do+
−
   {+
−
      /* Compress the data */+
−
      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);+
−
      if (ret != Z_OK)+
−
      {+
−
         /* Error */+
−
         if (png_ptr->zstream.msg != NULL)+
−
            png_error(png_ptr, png_ptr->zstream.msg);+
−
         else+
−
            png_error(png_ptr, "zlib error");+
−
      }+
−
      /* Check to see if we need more room */+
−
      if (!(png_ptr->zstream.avail_out))+
−
      {+
−
         /* Make sure the output array has room */+
−
         if (comp->num_output_ptr >= comp->max_output_ptr)+
−
         {+
−
            int old_max;+
−
+
−
            old_max = comp->max_output_ptr;+
−
            comp->max_output_ptr = comp->num_output_ptr + 4;+
−
            if (comp->output_ptr != NULL)+
−
            {+
−
               png_charpp old_ptr;+
−
+
−
               old_ptr = comp->output_ptr;+
−
               comp->output_ptr = (png_charpp)png_malloc(png_ptr,+
−
                  (png_uint_32)+
−
                  (comp->max_output_ptr * png_sizeof(png_charpp)));+
−
               png_memcpy(comp->output_ptr, old_ptr, old_max+
−
                  * png_sizeof(png_charp));+
−
               png_free(png_ptr, old_ptr);+
−
            }+
−
            else+
−
               comp->output_ptr = (png_charpp)png_malloc(png_ptr,+
−
                  (png_uint_32)+
−
                  (comp->max_output_ptr * png_sizeof(png_charp)));+
−
         }+
−
+
−
         /* Save the data */+
−
         comp->output_ptr[comp->num_output_ptr] =+
−
            (png_charp)png_malloc(png_ptr,+
−
            (png_uint_32)png_ptr->zbuf_size);+
−
         png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,+
−
            png_ptr->zbuf_size);+
−
         comp->num_output_ptr++;+
−
+
−
         /* and reset the buffer */+
−
         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;+
−
         png_ptr->zstream.next_out = png_ptr->zbuf;+
−
      }+
−
   /* Continue until we don't have any more to compress */+
−
   } while (png_ptr->zstream.avail_in);+
−
+
−
   /* Finish the compression */+
−
   do+
−
   {+
−
      /* Tell zlib we are finished */+
−
      ret = deflate(&png_ptr->zstream, Z_FINISH);+
−
+
−
      if (ret == Z_OK)+
−
      {+
−
         /* Check to see if we need more room */+
−
         if (!(png_ptr->zstream.avail_out))+
−
         {+
−
            /* Check to make sure our output array has room */+
−
            if (comp->num_output_ptr >= comp->max_output_ptr)+
−
            {+
−
               int old_max;+
−
+
−
               old_max = comp->max_output_ptr;+
−
               comp->max_output_ptr = comp->num_output_ptr + 4;+
−
               if (comp->output_ptr != NULL)+
−
               {+
−
                  png_charpp old_ptr;+
−
+
−
                  old_ptr = comp->output_ptr;+
−
                  /* This could be optimized to realloc() */+
−
                  comp->output_ptr = (png_charpp)png_malloc(png_ptr,+
−
                     (png_uint_32)(comp->max_output_ptr *+
−
                     png_sizeof(png_charp)));+
−
                  png_memcpy(comp->output_ptr, old_ptr,+
−
                     old_max * png_sizeof(png_charp));+
−
                  png_free(png_ptr, old_ptr);+
−
               }+
−
               else+
−
                  comp->output_ptr = (png_charpp)png_malloc(png_ptr,+
−
                     (png_uint_32)(comp->max_output_ptr *+
−
                     png_sizeof(png_charp)));+
−
            }+
−
+
−
            /* Save the data */+
−
            comp->output_ptr[comp->num_output_ptr] =+
−
               (png_charp)png_malloc(png_ptr,+
−
               (png_uint_32)png_ptr->zbuf_size);+
−
            png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,+
−
               png_ptr->zbuf_size);+
−
            comp->num_output_ptr++;+
−
+
−
            /* and reset the buffer pointers */+
−
            png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;+
−
            png_ptr->zstream.next_out = png_ptr->zbuf;+
−
         }+
−
      }+
−
      else if (ret != Z_STREAM_END)+
−
      {+
−
         /* We got an error */+
−
         if (png_ptr->zstream.msg != NULL)+
−
            png_error(png_ptr, png_ptr->zstream.msg);+
−
         else+
−
            png_error(png_ptr, "zlib error");+
−
      }+
−
   } while (ret != Z_STREAM_END);+
−
+
−
   /* Text length is number of buffers plus last buffer */+
−
   text_len = png_ptr->zbuf_size * comp->num_output_ptr;+
−
   if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)+
−
      text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;+
−
+
−
   return((int)text_len);+
−
}+
−
+
−
/* Ship the compressed text out via chunk writes */+
−
static void /* PRIVATE */+
−
png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)+
−
{+
−
   int i;+
−
+
−
   /* Handle the no-compression case */+
−
   if (comp->input)+
−
   {+
−
      png_write_chunk_data(png_ptr, (png_bytep)comp->input,+
−
                            (png_size_t)comp->input_len);+
−
      return;+
−
   }+
−
+
−
   /* Write saved output buffers, if any */+
−
   for (i = 0; i < comp->num_output_ptr; i++)+
−
   {+
−
      png_write_chunk_data(png_ptr, (png_bytep)comp->output_ptr[i],+
−
         (png_size_t)png_ptr->zbuf_size);+
−
      png_free(png_ptr, comp->output_ptr[i]);+
−
       comp->output_ptr[i]=NULL;+
−
   }+
−
   if (comp->max_output_ptr != 0)+
−
      png_free(png_ptr, comp->output_ptr);+
−
       comp->output_ptr=NULL;+
−
   /* Write anything left in zbuf */+
−
   if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)+
−
      png_write_chunk_data(png_ptr, png_ptr->zbuf,+
−
         (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));+
−
+
−
   /* Reset zlib for another zTXt/iTXt or image data */+
−
   deflateReset(&png_ptr->zstream);+
−
   png_ptr->zstream.data_type = Z_BINARY;+
−
}+
−
#endif+
−
+
−
/* Write the IHDR chunk, and update the png_struct with the necessary+
−
 * information.  Note that the rest of this code depends upon this+
−
 * information being correct.+
−
 */+
−
void /* PRIVATE */+
−
png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,+
−
   int bit_depth, int color_type, int compression_type, int filter_type,+
−
   int interlace_type)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_IHDR;+
−
#endif+
−
   int ret;+
−
+
−
   png_byte buf[13]; /* Buffer to store the IHDR info */+
−
+
−
   png_debug(1, "in png_write_IHDR");+
−
+
−
   /* Check that we have valid input data from the application info */+
−
   switch (color_type)+
−
   {+
−
      case PNG_COLOR_TYPE_GRAY:+
−
         switch (bit_depth)+
−
         {+
−
            case 1:+
−
            case 2:+
−
            case 4:+
−
            case 8:+
−
            case 16: png_ptr->channels = 1; break;+
−
            default: png_error(png_ptr, "Invalid bit depth for grayscale image");+
−
         }+
−
         break;+
−
      case PNG_COLOR_TYPE_RGB:+
−
         if (bit_depth != 8 && bit_depth != 16)+
−
            png_error(png_ptr, "Invalid bit depth for RGB image");+
−
         png_ptr->channels = 3;+
−
         break;+
−
      case PNG_COLOR_TYPE_PALETTE:+
−
         switch (bit_depth)+
−
         {+
−
            case 1:+
−
            case 2:+
−
            case 4:+
−
            case 8: png_ptr->channels = 1; break;+
−
            default: png_error(png_ptr, "Invalid bit depth for paletted image");+
−
         }+
−
         break;+
−
      case PNG_COLOR_TYPE_GRAY_ALPHA:+
−
         if (bit_depth != 8 && bit_depth != 16)+
−
            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");+
−
         png_ptr->channels = 2;+
−
         break;+
−
      case PNG_COLOR_TYPE_RGB_ALPHA:+
−
         if (bit_depth != 8 && bit_depth != 16)+
−
            png_error(png_ptr, "Invalid bit depth for RGBA image");+
−
         png_ptr->channels = 4;+
−
         break;+
−
      default:+
−
         png_error(png_ptr, "Invalid image color type specified");+
−
   }+
−
+
−
   if (compression_type != PNG_COMPRESSION_TYPE_BASE)+
−
   {+
−
      png_warning(png_ptr, "Invalid compression type specified");+
−
      compression_type = PNG_COMPRESSION_TYPE_BASE;+
−
   }+
−
+
−
   /* Write filter_method 64 (intrapixel differencing) only if+
−
    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and+
−
    * 2. Libpng did not write a PNG signature (this filter_method is only+
−
    *    used in PNG datastreams that are embedded in MNG datastreams) and+
−
    * 3. The application called png_permit_mng_features with a mask that+
−
    *    included PNG_FLAG_MNG_FILTER_64 and+
−
    * 4. The filter_method is 64 and+
−
    * 5. The color_type is RGB or RGBA+
−
    */+
−
   if (+
−
#if defined(PNG_MNG_FEATURES_SUPPORTED)+
−
      !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&+
−
      ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&+
−
      (color_type == PNG_COLOR_TYPE_RGB ||+
−
       color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&+
−
      (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&+
−
#endif+
−
      filter_type != PNG_FILTER_TYPE_BASE)+
−
   {+
−
      png_warning(png_ptr, "Invalid filter type specified");+
−
      filter_type = PNG_FILTER_TYPE_BASE;+
−
   }+
−
+
−
#ifdef PNG_WRITE_INTERLACING_SUPPORTED+
−
   if (interlace_type != PNG_INTERLACE_NONE &&+
−
      interlace_type != PNG_INTERLACE_ADAM7)+
−
   {+
−
      png_warning(png_ptr, "Invalid interlace type specified");+
−
      interlace_type = PNG_INTERLACE_ADAM7;+
−
   }+
−
#else+
−
   interlace_type=PNG_INTERLACE_NONE;+
−
#endif+
−
+
−
   /* Save the relevent information */+
−
   png_ptr->bit_depth = (png_byte)bit_depth;+
−
   png_ptr->color_type = (png_byte)color_type;+
−
   png_ptr->interlaced = (png_byte)interlace_type;+
−
#if defined(PNG_MNG_FEATURES_SUPPORTED)+
−
   png_ptr->filter_type = (png_byte)filter_type;+
−
#endif+
−
   png_ptr->compression_type = (png_byte)compression_type;+
−
   png_ptr->width = width;+
−
   png_ptr->height = height;+
−
+
−
   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);+
−
   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);+
−
   /* Set the usr info, so any transformations can modify it */+
−
   png_ptr->usr_width = png_ptr->width;+
−
   png_ptr->usr_bit_depth = png_ptr->bit_depth;+
−
   png_ptr->usr_channels = png_ptr->channels;+
−
+
−
   /* Pack the header information into the buffer */+
−
   png_save_uint_32(buf, width);+
−
   png_save_uint_32(buf + 4, height);+
−
   buf[8] = (png_byte)bit_depth;+
−
   buf[9] = (png_byte)color_type;+
−
   buf[10] = (png_byte)compression_type;+
−
   buf[11] = (png_byte)filter_type;+
−
   buf[12] = (png_byte)interlace_type;+
−
+
−
   /* Write the chunk */+
−
   png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);+
−
+
−
   /* Initialize zlib with PNG info */+
−
   png_ptr->zstream.zalloc = png_zalloc;+
−
   png_ptr->zstream.zfree = png_zfree;+
−
   png_ptr->zstream.opaque = (voidpf)png_ptr;+
−
   if (!(png_ptr->do_filter))+
−
   {+
−
      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||+
−
         png_ptr->bit_depth < 8)+
−
         png_ptr->do_filter = PNG_FILTER_NONE;+
−
      else+
−
         png_ptr->do_filter = PNG_ALL_FILTERS;+
−
   }+
−
   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))+
−
   {+
−
      if (png_ptr->do_filter != PNG_FILTER_NONE)+
−
         png_ptr->zlib_strategy = Z_FILTERED;+
−
      else+
−
         png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;+
−
   }+
−
   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))+
−
      png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;+
−
   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))+
−
      png_ptr->zlib_mem_level = 8;+
−
   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))+
−
      png_ptr->zlib_window_bits = 15;+
−
   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))+
−
      png_ptr->zlib_method = 8;+
−
   ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,+
−
         png_ptr->zlib_method, png_ptr->zlib_window_bits,+
−
         png_ptr->zlib_mem_level, png_ptr->zlib_strategy);+
−
   if (ret != Z_OK)+
−
   {+
−
      if (ret == Z_VERSION_ERROR) png_error(png_ptr,+
−
          "zlib failed to initialize compressor -- version error");+
−
      if (ret == Z_STREAM_ERROR) png_error(png_ptr,+
−
           "zlib failed to initialize compressor -- stream error");+
−
      if (ret == Z_MEM_ERROR) png_error(png_ptr,+
−
           "zlib failed to initialize compressor -- mem error");+
−
      png_error(png_ptr, "zlib failed to initialize compressor");+
−
   }+
−
   png_ptr->zstream.next_out = png_ptr->zbuf;+
−
   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;+
−
   /* libpng is not interested in zstream.data_type */+
−
   /* Set it to a predefined value, to avoid its evaluation inside zlib */+
−
   png_ptr->zstream.data_type = Z_BINARY;+
−
+
−
   png_ptr->mode = PNG_HAVE_IHDR;+
−
}+
−
+
−
/* Write the palette.  We are careful not to trust png_color to be in the+
−
 * correct order for PNG, so people can redefine it to any convenient+
−
 * structure.+
−
 */+
−
void /* PRIVATE */+
−
png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_PLTE;+
−
#endif+
−
   png_uint_32 i;+
−
   png_colorp pal_ptr;+
−
   png_byte buf[3];+
−
+
−
   png_debug(1, "in png_write_PLTE");+
−
+
−
   if ((+
−
#if defined(PNG_MNG_FEATURES_SUPPORTED)+
−
        !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&+
−
#endif+
−
        num_pal == 0) || num_pal > 256)+
−
   {+
−
     if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)+
−
     {+
−
        png_error(png_ptr, "Invalid number of colors in palette");+
−
     }+
−
     else+
−
     {+
−
        png_warning(png_ptr, "Invalid number of colors in palette");+
−
        return;+
−
     }+
−
   }+
−
+
−
   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))+
−
   {+
−
      png_warning(png_ptr,+
−
        "Ignoring request to write a PLTE chunk in grayscale PNG");+
−
      return;+
−
   }+
−
+
−
   png_ptr->num_palette = (png_uint_16)num_pal;+
−
   png_debug1(3, "num_palette = %d", png_ptr->num_palette);+
−
+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_PLTE,+
−
     (png_uint_32)(num_pal * 3));+
−
#ifndef PNG_NO_POINTER_INDEXING+
−
   for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)+
−
   {+
−
      buf[0] = pal_ptr->red;+
−
      buf[1] = pal_ptr->green;+
−
      buf[2] = pal_ptr->blue;+
−
      png_write_chunk_data(png_ptr, buf, (png_size_t)3);+
−
   }+
−
#else+
−
   /* This is a little slower but some buggy compilers need to do this instead */+
−
   pal_ptr=palette;+
−
   for (i = 0; i < num_pal; i++)+
−
   {+
−
      buf[0] = pal_ptr[i].red;+
−
      buf[1] = pal_ptr[i].green;+
−
      buf[2] = pal_ptr[i].blue;+
−
      png_write_chunk_data(png_ptr, buf, (png_size_t)3);+
−
   }+
−
#endif+
−
   png_write_chunk_end(png_ptr);+
−
   png_ptr->mode |= PNG_HAVE_PLTE;+
−
}+
−
+
−
/* Write an IDAT chunk */+
−
void /* PRIVATE */+
−
png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_IDAT;+
−
#endif+
−
+
−
   png_debug(1, "in png_write_IDAT");+
−
+
−
   /* Optimize the CMF field in the zlib stream. */+
−
   /* This hack of the zlib stream is compliant to the stream specification. */+
−
   if (!(png_ptr->mode & PNG_HAVE_IDAT) &&+
−
       png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)+
−
   {+
−
      unsigned int z_cmf = data[0];  /* zlib compression method and flags */+
−
      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)+
−
      {+
−
         /* Avoid memory underflows and multiplication overflows.+
−
          *+
−
          * The conditions below are practically always satisfied;+
−
          * however, they still must be checked.+
−
          */+
−
         if (length >= 2 &&+
−
             png_ptr->height < 16384 && png_ptr->width < 16384)+
−
         {+
−
            png_uint_32 uncompressed_idat_size = png_ptr->height *+
−
               ((png_ptr->width *+
−
               png_ptr->channels * png_ptr->bit_depth + 15) >> 3);+
−
            unsigned int z_cinfo = z_cmf >> 4;+
−
            unsigned int half_z_window_size = 1 << (z_cinfo + 7);+
−
            while (uncompressed_idat_size <= half_z_window_size &&+
−
                   half_z_window_size >= 256)+
−
            {+
−
               z_cinfo--;+
−
               half_z_window_size >>= 1;+
−
            }+
−
            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);+
−
            if (data[0] != (png_byte)z_cmf)+
−
            {+
−
               data[0] = (png_byte)z_cmf;+
−
               data[1] &= 0xe0;+
−
               data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);+
−
            }+
−
         }+
−
      }+
−
      else+
−
         png_error(png_ptr,+
−
            "Invalid zlib compression method or flags in IDAT");+
−
   }+
−
+
−
   png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);+
−
   png_ptr->mode |= PNG_HAVE_IDAT;+
−
}+
−
+
−
/* Write an IEND chunk */+
−
void /* PRIVATE */+
−
png_write_IEND(png_structp png_ptr)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_IEND;+
−
#endif+
−
+
−
   png_debug(1, "in png_write_IEND");+
−
+
−
   png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,+
−
     (png_size_t)0);+
−
   png_ptr->mode |= PNG_HAVE_IEND;+
−
}+
−
+
−
#if defined(PNG_WRITE_gAMA_SUPPORTED)+
−
/* Write a gAMA chunk */+
−
#ifdef PNG_FLOATING_POINT_SUPPORTED+
−
void /* PRIVATE */+
−
png_write_gAMA(png_structp png_ptr, double file_gamma)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_gAMA;+
−
#endif+
−
   png_uint_32 igamma;+
−
   png_byte buf[4];+
−
+
−
   png_debug(1, "in png_write_gAMA");+
−
+
−
   /* file_gamma is saved in 1/100,000ths */+
−
   igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);+
−
   png_save_uint_32(buf, igamma);+
−
   png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);+
−
}+
−
#endif+
−
#ifdef PNG_FIXED_POINT_SUPPORTED+
−
void /* PRIVATE */+
−
png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_gAMA;+
−
#endif+
−
   png_byte buf[4];+
−
+
−
   png_debug(1, "in png_write_gAMA");+
−
+
−
   /* file_gamma is saved in 1/100,000ths */+
−
   png_save_uint_32(buf, (png_uint_32)file_gamma);+
−
   png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);+
−
}+
−
#endif+
−
#endif+
−
+
−
#if defined(PNG_WRITE_sRGB_SUPPORTED)+
−
/* Write a sRGB chunk */+
−
void /* PRIVATE */+
−
png_write_sRGB(png_structp png_ptr, int srgb_intent)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_sRGB;+
−
#endif+
−
   png_byte buf[1];+
−
+
−
   png_debug(1, "in png_write_sRGB");+
−
+
−
   if (srgb_intent >= PNG_sRGB_INTENT_LAST)+
−
         png_warning(png_ptr,+
−
            "Invalid sRGB rendering intent specified");+
−
   buf[0]=(png_byte)srgb_intent;+
−
   png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_iCCP_SUPPORTED)+
−
/* Write an iCCP chunk */+
−
void /* PRIVATE */+
−
png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,+
−
   png_charp profile, int profile_len)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_iCCP;+
−
#endif+
−
   png_size_t name_len;+
−
   png_charp new_name;+
−
   compression_state comp;+
−
   int embedded_profile_len = 0;+
−
+
−
   png_debug(1, "in png_write_iCCP");+
−
+
−
   comp.num_output_ptr = 0;+
−
   comp.max_output_ptr = 0;+
−
   comp.output_ptr = NULL;+
−
   comp.input = NULL;+
−
   comp.input_len = 0;+
−
+
−
   if ((name_len = png_check_keyword(png_ptr, name,+
−
      &new_name)) == 0)+
−
      return;+
−
+
−
   if (compression_type != PNG_COMPRESSION_TYPE_BASE)+
−
      png_warning(png_ptr, "Unknown compression type in iCCP chunk");+
−
+
−
   if (profile == NULL)+
−
      profile_len = 0;+
−
+
−
   if (profile_len > 3)+
−
      embedded_profile_len =+
−
          ((*( (png_bytep)profile    ))<<24) |+
−
          ((*( (png_bytep)profile + 1))<<16) |+
−
          ((*( (png_bytep)profile + 2))<< 8) |+
−
          ((*( (png_bytep)profile + 3))    );+
−
+
−
   if (embedded_profile_len < 0)+
−
   {+
−
      png_warning(png_ptr,+
−
        "Embedded profile length in iCCP chunk is negative");+
−
      png_free(png_ptr, new_name);+
−
      return;+
−
   }+
−
+
−
   if (profile_len < embedded_profile_len)+
−
   {+
−
      png_warning(png_ptr,+
−
        "Embedded profile length too large in iCCP chunk");+
−
      png_free(png_ptr, new_name);+
−
      return;+
−
   }+
−
+
−
   if (profile_len > embedded_profile_len)+
−
   {+
−
      png_warning(png_ptr,+
−
        "Truncating profile to actual length in iCCP chunk");+
−
      profile_len = embedded_profile_len;+
−
   }+
−
+
−
   if (profile_len)+
−
      profile_len = png_text_compress(png_ptr, profile,+
−
        (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);+
−
+
−
   /* Make sure we include the NULL after the name and the compression type */+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,+
−
          (png_uint_32)(name_len + profile_len + 2));+
−
   new_name[name_len + 1] = 0x00;+
−
   png_write_chunk_data(png_ptr, (png_bytep)new_name,+
−
     (png_size_t)(name_len + 2));+
−
+
−
   if (profile_len)+
−
      png_write_compressed_data_out(png_ptr, &comp);+
−
+
−
   png_write_chunk_end(png_ptr);+
−
   png_free(png_ptr, new_name);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_sPLT_SUPPORTED)+
−
/* Write a sPLT chunk */+
−
void /* PRIVATE */+
−
png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_sPLT;+
−
#endif+
−
   png_size_t name_len;+
−
   png_charp new_name;+
−
   png_byte entrybuf[10];+
−
   int entry_size = (spalette->depth == 8 ? 6 : 10);+
−
   int palette_size = entry_size * spalette->nentries;+
−
   png_sPLT_entryp ep;+
−
#ifdef PNG_NO_POINTER_INDEXING+
−
   int i;+
−
#endif+
−
+
−
   png_debug(1, "in png_write_sPLT");+
−
+
−
   if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)+
−
      return;+
−
+
−
   /* Make sure we include the NULL after the name */+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,+
−
     (png_uint_32)(name_len + 2 + palette_size));+
−
   png_write_chunk_data(png_ptr, (png_bytep)new_name,+
−
     (png_size_t)(name_len + 1));+
−
   png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);+
−
+
−
   /* Loop through each palette entry, writing appropriately */+
−
#ifndef PNG_NO_POINTER_INDEXING+
−
   for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)+
−
   {+
−
      if (spalette->depth == 8)+
−
      {+
−
          entrybuf[0] = (png_byte)ep->red;+
−
          entrybuf[1] = (png_byte)ep->green;+
−
          entrybuf[2] = (png_byte)ep->blue;+
−
          entrybuf[3] = (png_byte)ep->alpha;+
−
          png_save_uint_16(entrybuf + 4, ep->frequency);+
−
      }+
−
      else+
−
      {+
−
          png_save_uint_16(entrybuf + 0, ep->red);+
−
          png_save_uint_16(entrybuf + 2, ep->green);+
−
          png_save_uint_16(entrybuf + 4, ep->blue);+
−
          png_save_uint_16(entrybuf + 6, ep->alpha);+
−
          png_save_uint_16(entrybuf + 8, ep->frequency);+
−
      }+
−
      png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);+
−
   }+
−
#else+
−
   ep=spalette->entries;+
−
   for (i=0; i>spalette->nentries; i++)+
−
   {+
−
      if (spalette->depth == 8)+
−
      {+
−
          entrybuf[0] = (png_byte)ep[i].red;+
−
          entrybuf[1] = (png_byte)ep[i].green;+
−
          entrybuf[2] = (png_byte)ep[i].blue;+
−
          entrybuf[3] = (png_byte)ep[i].alpha;+
−
          png_save_uint_16(entrybuf + 4, ep[i].frequency);+
−
      }+
−
      else+
−
      {+
−
          png_save_uint_16(entrybuf + 0, ep[i].red);+
−
          png_save_uint_16(entrybuf + 2, ep[i].green);+
−
          png_save_uint_16(entrybuf + 4, ep[i].blue);+
−
          png_save_uint_16(entrybuf + 6, ep[i].alpha);+
−
          png_save_uint_16(entrybuf + 8, ep[i].frequency);+
−
      }+
−
      png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);+
−
   }+
−
#endif+
−
+
−
   png_write_chunk_end(png_ptr);+
−
   png_free(png_ptr, new_name);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_sBIT_SUPPORTED)+
−
/* Write the sBIT chunk */+
−
void /* PRIVATE */+
−
png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_sBIT;+
−
#endif+
−
   png_byte buf[4];+
−
   png_size_t size;+
−
+
−
   png_debug(1, "in png_write_sBIT");+
−
+
−
   /* Make sure we don't depend upon the order of PNG_COLOR_8 */+
−
   if (color_type & PNG_COLOR_MASK_COLOR)+
−
   {+
−
      png_byte maxbits;+
−
+
−
      maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :+
−
                png_ptr->usr_bit_depth);+
−
      if (sbit->red == 0 || sbit->red > maxbits ||+
−
          sbit->green == 0 || sbit->green > maxbits ||+
−
          sbit->blue == 0 || sbit->blue > maxbits)+
−
      {+
−
         png_warning(png_ptr, "Invalid sBIT depth specified");+
−
         return;+
−
      }+
−
      buf[0] = sbit->red;+
−
      buf[1] = sbit->green;+
−
      buf[2] = sbit->blue;+
−
      size = 3;+
−
   }+
−
   else+
−
   {+
−
      if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)+
−
      {+
−
         png_warning(png_ptr, "Invalid sBIT depth specified");+
−
         return;+
−
      }+
−
      buf[0] = sbit->gray;+
−
      size = 1;+
−
   }+
−
+
−
   if (color_type & PNG_COLOR_MASK_ALPHA)+
−
   {+
−
      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)+
−
      {+
−
         png_warning(png_ptr, "Invalid sBIT depth specified");+
−
         return;+
−
      }+
−
      buf[size++] = sbit->alpha;+
−
   }+
−
+
−
   png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_cHRM_SUPPORTED)+
−
/* Write the cHRM chunk */+
−
#ifdef PNG_FLOATING_POINT_SUPPORTED+
−
void /* PRIVATE */+
−
png_write_cHRM(png_structp png_ptr, double white_x, double white_y,+
−
   double red_x, double red_y, double green_x, double green_y,+
−
   double blue_x, double blue_y)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_cHRM;+
−
#endif+
−
   png_byte buf[32];+
−
+
−
   png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y,+
−
      int_green_x, int_green_y, int_blue_x, int_blue_y;+
−
+
−
   png_debug(1, "in png_write_cHRM");+
−
+
−
   int_white_x = (png_uint_32)(white_x * 100000.0 + 0.5);+
−
   int_white_y = (png_uint_32)(white_y * 100000.0 + 0.5);+
−
   int_red_x   = (png_uint_32)(red_x   * 100000.0 + 0.5);+
−
   int_red_y   = (png_uint_32)(red_y   * 100000.0 + 0.5);+
−
   int_green_x = (png_uint_32)(green_x * 100000.0 + 0.5);+
−
   int_green_y = (png_uint_32)(green_y * 100000.0 + 0.5);+
−
   int_blue_x  = (png_uint_32)(blue_x  * 100000.0 + 0.5);+
−
   int_blue_y  = (png_uint_32)(blue_y  * 100000.0 + 0.5);+
−
+
−
#if !defined(PNG_NO_CHECK_cHRM)+
−
   if (png_check_cHRM_fixed(png_ptr, int_white_x, int_white_y,+
−
      int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y))+
−
#endif+
−
   {+
−
      /* Each value is saved in 1/100,000ths */+
−
+
−
      png_save_uint_32(buf, int_white_x);+
−
      png_save_uint_32(buf + 4, int_white_y);+
−
+
−
      png_save_uint_32(buf + 8, int_red_x);+
−
      png_save_uint_32(buf + 12, int_red_y);+
−
+
−
      png_save_uint_32(buf + 16, int_green_x);+
−
      png_save_uint_32(buf + 20, int_green_y);+
−
+
−
      png_save_uint_32(buf + 24, int_blue_x);+
−
      png_save_uint_32(buf + 28, int_blue_y);+
−
+
−
      png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);+
−
   }+
−
}+
−
#endif+
−
#ifdef PNG_FIXED_POINT_SUPPORTED+
−
void /* PRIVATE */+
−
png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,+
−
   png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,+
−
   png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,+
−
   png_fixed_point blue_y)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_cHRM;+
−
#endif+
−
   png_byte buf[32];+
−
+
−
   png_debug(1, "in png_write_cHRM");+
−
+
−
   /* Each value is saved in 1/100,000ths */+
−
#if !defined(PNG_NO_CHECK_cHRM)+
−
   if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,+
−
      green_x, green_y, blue_x, blue_y))+
−
#endif+
−
   {+
−
      png_save_uint_32(buf, (png_uint_32)white_x);+
−
      png_save_uint_32(buf + 4, (png_uint_32)white_y);+
−
+
−
      png_save_uint_32(buf + 8, (png_uint_32)red_x);+
−
      png_save_uint_32(buf + 12, (png_uint_32)red_y);+
−
+
−
      png_save_uint_32(buf + 16, (png_uint_32)green_x);+
−
      png_save_uint_32(buf + 20, (png_uint_32)green_y);+
−
+
−
      png_save_uint_32(buf + 24, (png_uint_32)blue_x);+
−
      png_save_uint_32(buf + 28, (png_uint_32)blue_y);+
−
+
−
      png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);+
−
   }+
−
}+
−
#endif+
−
#endif+
−
+
−
#if defined(PNG_WRITE_tRNS_SUPPORTED)+
−
/* Write the tRNS chunk */+
−
void /* PRIVATE */+
−
png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,+
−
   int num_trans, int color_type)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_tRNS;+
−
#endif+
−
   png_byte buf[6];+
−
+
−
   png_debug(1, "in png_write_tRNS");+
−
+
−
   if (color_type == PNG_COLOR_TYPE_PALETTE)+
−
   {+
−
      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)+
−
      {+
−
         png_warning(png_ptr, "Invalid number of transparent colors specified");+
−
         return;+
−
      }+
−
      /* Write the chunk out as it is */+
−
      png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans,+
−
        (png_size_t)num_trans);+
−
   }+
−
   else if (color_type == PNG_COLOR_TYPE_GRAY)+
−
   {+
−
      /* One 16 bit value */+
−
      if (tran->gray >= (1 << png_ptr->bit_depth))+
−
      {+
−
         png_warning(png_ptr,+
−
           "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");+
−
         return;+
−
      }+
−
      png_save_uint_16(buf, tran->gray);+
−
      png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);+
−
   }+
−
   else if (color_type == PNG_COLOR_TYPE_RGB)+
−
   {+
−
      /* Three 16 bit values */+
−
      png_save_uint_16(buf, tran->red);+
−
      png_save_uint_16(buf + 2, tran->green);+
−
      png_save_uint_16(buf + 4, tran->blue);+
−
      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))+
−
      {+
−
         png_warning(png_ptr,+
−
           "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");+
−
         return;+
−
      }+
−
      png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);+
−
   }+
−
   else+
−
   {+
−
      png_warning(png_ptr, "Can't write tRNS with an alpha channel");+
−
   }+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_bKGD_SUPPORTED)+
−
/* Write the background chunk */+
−
void /* PRIVATE */+
−
png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_bKGD;+
−
#endif+
−
   png_byte buf[6];+
−
+
−
   png_debug(1, "in png_write_bKGD");+
−
+
−
   if (color_type == PNG_COLOR_TYPE_PALETTE)+
−
   {+
−
      if (+
−
#if defined(PNG_MNG_FEATURES_SUPPORTED)+
−
          (png_ptr->num_palette ||+
−
          (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&+
−
#endif+
−
         back->index >= png_ptr->num_palette)+
−
      {+
−
         png_warning(png_ptr, "Invalid background palette index");+
−
         return;+
−
      }+
−
      buf[0] = back->index;+
−
      png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);+
−
   }+
−
   else if (color_type & PNG_COLOR_MASK_COLOR)+
−
   {+
−
      png_save_uint_16(buf, back->red);+
−
      png_save_uint_16(buf + 2, back->green);+
−
      png_save_uint_16(buf + 4, back->blue);+
−
      if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))+
−
      {+
−
         png_warning(png_ptr,+
−
           "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");+
−
         return;+
−
      }+
−
      png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);+
−
   }+
−
   else+
−
   {+
−
      if (back->gray >= (1 << png_ptr->bit_depth))+
−
      {+
−
         png_warning(png_ptr,+
−
           "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");+
−
         return;+
−
      }+
−
      png_save_uint_16(buf, back->gray);+
−
      png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);+
−
   }+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_hIST_SUPPORTED)+
−
/* Write the histogram */+
−
void /* PRIVATE */+
−
png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_hIST;+
−
#endif+
−
   int i;+
−
   png_byte buf[3];+
−
+
−
   png_debug(1, "in png_write_hIST");+
−
+
−
   if (num_hist > (int)png_ptr->num_palette)+
−
   {+
−
      png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,+
−
         png_ptr->num_palette);+
−
      png_warning(png_ptr, "Invalid number of histogram entries specified");+
−
      return;+
−
   }+
−
+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_hIST,+
−
     (png_uint_32)(num_hist * 2));+
−
   for (i = 0; i < num_hist; i++)+
−
   {+
−
      png_save_uint_16(buf, hist[i]);+
−
      png_write_chunk_data(png_ptr, buf, (png_size_t)2);+
−
   }+
−
   png_write_chunk_end(png_ptr);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \+
−
    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)+
−
/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,+
−
 * and if invalid, correct the keyword rather than discarding the entire+
−
 * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in+
−
 * length, forbids leading or trailing whitespace, multiple internal spaces,+
−
 * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.+
−
 *+
−
 * The new_key is allocated to hold the corrected keyword and must be freed+
−
 * by the calling routine.  This avoids problems with trying to write to+
−
 * static keywords without having to have duplicate copies of the strings.+
−
 */+
−
png_size_t /* PRIVATE */+
−
png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)+
−
{+
−
   png_size_t key_len;+
−
   png_charp kp, dp;+
−
   int kflag;+
−
   int kwarn=0;+
−
+
−
   png_debug(1, "in png_check_keyword");+
−
+
−
   *new_key = NULL;+
−
+
−
   if (key == NULL || (key_len = png_strlen(key)) == 0)+
−
   {+
−
      png_warning(png_ptr, "zero length keyword");+
−
      return ((png_size_t)0);+
−
   }+
−
+
−
   png_debug1(2, "Keyword to be checked is '%s'", key);+
−
+
−
   *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));+
−
   if (*new_key == NULL)+
−
   {+
−
      png_warning(png_ptr, "Out of memory while procesing keyword");+
−
      return ((png_size_t)0);+
−
   }+
−
+
−
   /* Replace non-printing characters with a blank and print a warning */+
−
   for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)+
−
   {+
−
      if ((png_byte)*kp < 0x20 ||+
−
         ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))+
−
      {+
−
#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)+
−
         char msg[40];+
−
+
−
         png_snprintf(msg, 40,+
−
           "invalid keyword character 0x%02X", (png_byte)*kp);+
−
         png_warning(png_ptr, msg);+
−
#else+
−
         png_warning(png_ptr, "invalid character in keyword");+
−
#endif+
−
         *dp = ' ';+
−
      }+
−
      else+
−
      {+
−
         *dp = *kp;+
−
      }+
−
   }+
−
   *dp = '\0';+
−
+
−
   /* Remove any trailing white space. */+
−
   kp = *new_key + key_len - 1;+
−
   if (*kp == ' ')+
−
   {+
−
      png_warning(png_ptr, "trailing spaces removed from keyword");+
−
+
−
      while (*kp == ' ')+
−
      {+
−
         *(kp--) = '\0';+
−
         key_len--;+
−
      }+
−
   }+
−
+
−
   /* Remove any leading white space. */+
−
   kp = *new_key;+
−
   if (*kp == ' ')+
−
   {+
−
      png_warning(png_ptr, "leading spaces removed from keyword");+
−
+
−
      while (*kp == ' ')+
−
      {+
−
         kp++;+
−
         key_len--;+
−
      }+
−
   }+
−
+
−
   png_debug1(2, "Checking for multiple internal spaces in '%s'", kp);+
−
+
−
   /* Remove multiple internal spaces. */+
−
   for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)+
−
   {+
−
      if (*kp == ' ' && kflag == 0)+
−
      {+
−
         *(dp++) = *kp;+
−
         kflag = 1;+
−
      }+
−
      else if (*kp == ' ')+
−
      {+
−
         key_len--;+
−
         kwarn=1;+
−
      }+
−
      else+
−
      {+
−
         *(dp++) = *kp;+
−
         kflag = 0;+
−
      }+
−
   }+
−
   *dp = '\0';+
−
   if (kwarn)+
−
      png_warning(png_ptr, "extra interior spaces removed from keyword");+
−
+
−
   if (key_len == 0)+
−
   {+
−
      png_free(png_ptr, *new_key);+
−
       *new_key=NULL;+
−
      png_warning(png_ptr, "Zero length keyword");+
−
   }+
−
+
−
   if (key_len > 79)+
−
   {+
−
      png_warning(png_ptr, "keyword length must be 1 - 79 characters");+
−
      (*new_key)[79] = '\0';+
−
      key_len = 79;+
−
   }+
−
+
−
   return (key_len);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_tEXt_SUPPORTED)+
−
/* Write a tEXt chunk */+
−
void /* PRIVATE */+
−
png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,+
−
   png_size_t text_len)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_tEXt;+
−
#endif+
−
   png_size_t key_len;+
−
   png_charp new_key;+
−
+
−
   png_debug(1, "in png_write_tEXt");+
−
+
−
   if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)+
−
      return;+
−
+
−
   if (text == NULL || *text == '\0')+
−
      text_len = 0;+
−
   else+
−
      text_len = png_strlen(text);+
−
+
−
   /* Make sure we include the 0 after the key */+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_tEXt,+
−
      (png_uint_32)(key_len + text_len + 1));+
−
   /*+
−
    * We leave it to the application to meet PNG-1.0 requirements on the+
−
    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of+
−
    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.+
−
    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.+
−
    */+
−
   png_write_chunk_data(png_ptr, (png_bytep)new_key,+
−
     (png_size_t)(key_len + 1));+
−
   if (text_len)+
−
      png_write_chunk_data(png_ptr, (png_bytep)text, (png_size_t)text_len);+
−
+
−
   png_write_chunk_end(png_ptr);+
−
   png_free(png_ptr, new_key);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_zTXt_SUPPORTED)+
−
/* Write a compressed text chunk */+
−
void /* PRIVATE */+
−
png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,+
−
   png_size_t text_len, int compression)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_zTXt;+
−
#endif+
−
   png_size_t key_len;+
−
   char buf[1];+
−
   png_charp new_key;+
−
   compression_state comp;+
−
+
−
   png_debug(1, "in png_write_zTXt");+
−
+
−
   comp.num_output_ptr = 0;+
−
   comp.max_output_ptr = 0;+
−
   comp.output_ptr = NULL;+
−
   comp.input = NULL;+
−
   comp.input_len = 0;+
−
+
−
   if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)+
−
   {+
−
      png_free(png_ptr, new_key);+
−
      return;+
−
   }+
−
+
−
   if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)+
−
   {+
−
      png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);+
−
      png_free(png_ptr, new_key);+
−
      return;+
−
   }+
−
+
−
   text_len = png_strlen(text);+
−
+
−
   /* Compute the compressed data; do it now for the length */+
−
   text_len = png_text_compress(png_ptr, text, text_len, compression,+
−
       &comp);+
−
+
−
   /* Write start of chunk */+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_zTXt,+
−
     (png_uint_32)(key_len+text_len + 2));+
−
   /* Write key */+
−
   png_write_chunk_data(png_ptr, (png_bytep)new_key,+
−
     (png_size_t)(key_len + 1));+
−
   png_free(png_ptr, new_key);+
−
+
−
   buf[0] = (png_byte)compression;+
−
   /* Write compression */+
−
   png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);+
−
   /* Write the compressed data */+
−
   png_write_compressed_data_out(png_ptr, &comp);+
−
+
−
   /* Close the chunk */+
−
   png_write_chunk_end(png_ptr);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_iTXt_SUPPORTED)+
−
/* Write an iTXt chunk */+
−
void /* PRIVATE */+
−
png_write_iTXt(png_structp png_ptr, int compression, png_charp key,+
−
    png_charp lang, png_charp lang_key, png_charp text)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_iTXt;+
−
#endif+
−
   png_size_t lang_len, key_len, lang_key_len, text_len;+
−
   png_charp new_lang;+
−
   png_charp new_key = NULL;+
−
   png_byte cbuf[2];+
−
   compression_state comp;+
−
+
−
   png_debug(1, "in png_write_iTXt");+
−
+
−
   comp.num_output_ptr = 0;+
−
   comp.max_output_ptr = 0;+
−
   comp.output_ptr = NULL;+
−
   comp.input = NULL;+
−
+
−
   if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)+
−
      return;+
−
+
−
   if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)+
−
   {+
−
      png_warning(png_ptr, "Empty language field in iTXt chunk");+
−
      new_lang = NULL;+
−
      lang_len = 0;+
−
   }+
−
+
−
   if (lang_key == NULL)+
−
      lang_key_len = 0;+
−
   else+
−
      lang_key_len = png_strlen(lang_key);+
−
+
−
   if (text == NULL)+
−
      text_len = 0;+
−
   else+
−
      text_len = png_strlen(text);+
−
+
−
   /* Compute the compressed data; do it now for the length */+
−
   text_len = png_text_compress(png_ptr, text, text_len, compression-2,+
−
      &comp);+
−
+
−
+
−
   /* Make sure we include the compression flag, the compression byte,+
−
    * and the NULs after the key, lang, and lang_key parts */+
−
+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,+
−
          (png_uint_32)(+
−
        5 /* comp byte, comp flag, terminators for key, lang and lang_key */+
−
        + key_len+
−
        + lang_len+
−
        + lang_key_len+
−
        + text_len));+
−
+
−
   /* We leave it to the application to meet PNG-1.0 requirements on the+
−
    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of+
−
    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.+
−
    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.+
−
    */+
−
   png_write_chunk_data(png_ptr, (png_bytep)new_key,+
−
     (png_size_t)(key_len + 1));+
−
+
−
   /* Set the compression flag */+
−
   if (compression == PNG_ITXT_COMPRESSION_NONE || \+
−
       compression == PNG_TEXT_COMPRESSION_NONE)+
−
       cbuf[0] = 0;+
−
   else /* compression == PNG_ITXT_COMPRESSION_zTXt */+
−
       cbuf[0] = 1;+
−
   /* Set the compression method */+
−
   cbuf[1] = 0;+
−
   png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);+
−
+
−
   cbuf[0] = 0;+
−
   png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf),+
−
     (png_size_t)(lang_len + 1));+
−
   png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf),+
−
     (png_size_t)(lang_key_len + 1));+
−
   png_write_compressed_data_out(png_ptr, &comp);+
−
+
−
   png_write_chunk_end(png_ptr);+
−
   png_free(png_ptr, new_key);+
−
   png_free(png_ptr, new_lang);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_oFFs_SUPPORTED)+
−
/* Write the oFFs chunk */+
−
void /* PRIVATE */+
−
png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,+
−
   int unit_type)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_oFFs;+
−
#endif+
−
   png_byte buf[9];+
−
+
−
   png_debug(1, "in png_write_oFFs");+
−
+
−
   if (unit_type >= PNG_OFFSET_LAST)+
−
      png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");+
−
+
−
   png_save_int_32(buf, x_offset);+
−
   png_save_int_32(buf + 4, y_offset);+
−
   buf[8] = (png_byte)unit_type;+
−
+
−
   png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);+
−
}+
−
#endif+
−
#if defined(PNG_WRITE_pCAL_SUPPORTED)+
−
/* Write the pCAL chunk (described in the PNG extensions document) */+
−
void /* PRIVATE */+
−
png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,+
−
   png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_pCAL;+
−
#endif+
−
   png_size_t purpose_len, units_len, total_len;+
−
   png_uint_32p params_len;+
−
   png_byte buf[10];+
−
   png_charp new_purpose;+
−
   int i;+
−
+
−
   png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);+
−
+
−
   if (type >= PNG_EQUATION_LAST)+
−
      png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");+
−
+
−
   purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;+
−
   png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);+
−
   units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);+
−
   png_debug1(3, "pCAL units length = %d", (int)units_len);+
−
   total_len = purpose_len + units_len + 10;+
−
+
−
   params_len = (png_uint_32p)png_malloc(png_ptr,+
−
      (png_uint_32)(nparams * png_sizeof(png_uint_32)));+
−
+
−
   /* Find the length of each parameter, making sure we don't count the+
−
      null terminator for the last parameter. */+
−
   for (i = 0; i < nparams; i++)+
−
   {+
−
      params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);+
−
      png_debug2(3, "pCAL parameter %d length = %lu", i,+
−
        (unsigned long) params_len[i]);+
−
      total_len += (png_size_t)params_len[i];+
−
   }+
−
+
−
   png_debug1(3, "pCAL total length = %d", (int)total_len);+
−
   png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);+
−
   png_write_chunk_data(png_ptr, (png_bytep)new_purpose,+
−
     (png_size_t)purpose_len);+
−
   png_save_int_32(buf, X0);+
−
   png_save_int_32(buf + 4, X1);+
−
   buf[8] = (png_byte)type;+
−
   buf[9] = (png_byte)nparams;+
−
   png_write_chunk_data(png_ptr, buf, (png_size_t)10);+
−
   png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);+
−
+
−
   png_free(png_ptr, new_purpose);+
−
+
−
   for (i = 0; i < nparams; i++)+
−
   {+
−
      png_write_chunk_data(png_ptr, (png_bytep)params[i],+
−
         (png_size_t)params_len[i]);+
−
   }+
−
+
−
   png_free(png_ptr, params_len);+
−
   png_write_chunk_end(png_ptr);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_sCAL_SUPPORTED)+
−
/* Write the sCAL chunk */+
−
#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)+
−
void /* PRIVATE */+
−
png_write_sCAL(png_structp png_ptr, int unit, double width, double height)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_sCAL;+
−
#endif+
−
   char buf[64];+
−
   png_size_t total_len;+
−
+
−
   png_debug(1, "in png_write_sCAL");+
−
+
−
   buf[0] = (char)unit;+
−
#if defined(_WIN32_WCE)+
−
/* sprintf() function is not supported on WindowsCE */+
−
   {+
−
      wchar_t wc_buf[32];+
−
      size_t wc_len;+
−
      swprintf(wc_buf, TEXT("%12.12e"), width);+
−
      wc_len = wcslen(wc_buf);+
−
      WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, NULL);+
−
      total_len = wc_len + 2;+
−
      swprintf(wc_buf, TEXT("%12.12e"), height);+
−
      wc_len = wcslen(wc_buf);+
−
      WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + total_len, wc_len,+
−
         NULL, NULL);+
−
      total_len += wc_len;+
−
   }+
−
#else+
−
   png_snprintf(buf + 1, 63, "%12.12e", width);+
−
   total_len = 1 + png_strlen(buf + 1) + 1;+
−
   png_snprintf(buf + total_len, 64-total_len, "%12.12e", height);+
−
   total_len += png_strlen(buf + total_len);+
−
#endif+
−
+
−
   png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);+
−
   png_write_chunk(png_ptr, (png_bytep)png_sCAL, (png_bytep)buf, total_len);+
−
}+
−
#else+
−
#ifdef PNG_FIXED_POINT_SUPPORTED+
−
void /* PRIVATE */+
−
png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,+
−
   png_charp height)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_sCAL;+
−
#endif+
−
   png_byte buf[64];+
−
   png_size_t wlen, hlen, total_len;+
−
+
−
   png_debug(1, "in png_write_sCAL_s");+
−
+
−
   wlen = png_strlen(width);+
−
   hlen = png_strlen(height);+
−
   total_len = wlen + hlen + 2;+
−
   if (total_len > 64)+
−
   {+
−
      png_warning(png_ptr, "Can't write sCAL (buffer too small)");+
−
      return;+
−
   }+
−
+
−
   buf[0] = (png_byte)unit;+
−
   png_memcpy(buf + 1, width, wlen + 1);      /* Append the '\0' here */+
−
   png_memcpy(buf + wlen + 2, height, hlen);  /* Do NOT append the '\0' here */+
−
+
−
   png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);+
−
   png_write_chunk(png_ptr, (png_bytep)png_sCAL, buf, total_len);+
−
}+
−
#endif+
−
#endif+
−
#endif+
−
+
−
#if defined(PNG_WRITE_pHYs_SUPPORTED)+
−
/* Write the pHYs chunk */+
−
void /* PRIVATE */+
−
png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,+
−
   png_uint_32 y_pixels_per_unit,+
−
   int unit_type)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_pHYs;+
−
#endif+
−
   png_byte buf[9];+
−
+
−
   png_debug(1, "in png_write_pHYs");+
−
+
−
   if (unit_type >= PNG_RESOLUTION_LAST)+
−
      png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");+
−
+
−
   png_save_uint_32(buf, x_pixels_per_unit);+
−
   png_save_uint_32(buf + 4, y_pixels_per_unit);+
−
   buf[8] = (png_byte)unit_type;+
−
+
−
   png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);+
−
}+
−
#endif+
−
+
−
#if defined(PNG_WRITE_tIME_SUPPORTED)+
−
/* Write the tIME chunk.  Use either png_convert_from_struct_tm()+
−
 * or png_convert_from_time_t(), or fill in the structure yourself.+
−
 */+
−
void /* PRIVATE */+
−
png_write_tIME(png_structp png_ptr, png_timep mod_time)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   PNG_tIME;+
−
#endif+
−
   png_byte buf[7];+
−
+
−
   png_debug(1, "in png_write_tIME");+
−
+
−
   if (mod_time->month  > 12 || mod_time->month  < 1 ||+
−
       mod_time->day    > 31 || mod_time->day    < 1 ||+
−
       mod_time->hour   > 23 || mod_time->second > 60)+
−
   {+
−
      png_warning(png_ptr, "Invalid time specified for tIME chunk");+
−
      return;+
−
   }+
−
+
−
   png_save_uint_16(buf, mod_time->year);+
−
   buf[2] = mod_time->month;+
−
   buf[3] = mod_time->day;+
−
   buf[4] = mod_time->hour;+
−
   buf[5] = mod_time->minute;+
−
   buf[6] = mod_time->second;+
−
+
−
   png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);+
−
}+
−
#endif+
−
+
−
/* Initializes the row writing capability of libpng */+
−
void /* PRIVATE */+
−
png_write_start_row(png_structp png_ptr)+
−
{+
−
#ifdef PNG_WRITE_INTERLACING_SUPPORTED+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */+
−
+
−
   /* Start of interlace block */+
−
   int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};+
−
+
−
   /* Offset to next interlace block */+
−
   int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};+
−
+
−
   /* Start of interlace block in the y direction */+
−
   int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};+
−
+
−
   /* Offset to next interlace block in the y direction */+
−
   int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};+
−
#endif+
−
#endif+
−
+
−
   png_size_t buf_size;+
−
+
−
   png_debug(1, "in png_write_start_row");+
−
+
−
   buf_size = (png_size_t)(PNG_ROWBYTES(+
−
      png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);+
−
+
−
   /* Set up row buffer */+
−
   png_ptr->row_buf = (png_bytep)png_malloc(png_ptr,+
−
     (png_uint_32)buf_size);+
−
   png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;+
−
+
−
#ifndef PNG_NO_WRITE_FILTER+
−
   /* Set up filtering buffer, if using this filter */+
−
   if (png_ptr->do_filter & PNG_FILTER_SUB)+
−
   {+
−
      png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,+
−
         (png_uint_32)(png_ptr->rowbytes + 1));+
−
      png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;+
−
   }+
−
+
−
   /* We only need to keep the previous row if we are using one of these. */+
−
   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))+
−
   {+
−
     /* Set up previous row buffer */+
−
     png_ptr->prev_row = (png_bytep)png_malloc(png_ptr,+
−
        (png_uint_32)buf_size);+
−
     png_memset(png_ptr->prev_row, 0, buf_size);+
−
+
−
      if (png_ptr->do_filter & PNG_FILTER_UP)+
−
      {+
−
         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,+
−
           (png_uint_32)(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 = (png_bytep)png_malloc(png_ptr,+
−
           (png_uint_32)(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 = (png_bytep)png_malloc(png_ptr,+
−
           (png_uint_32)(png_ptr->rowbytes + 1));+
−
         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;+
−
      }+
−
   }+
−
#endif /* PNG_NO_WRITE_FILTER */+
−
+
−
#ifdef PNG_WRITE_INTERLACING_SUPPORTED+
−
   /* If interlaced, we need to set up width and height of pass */+
−
   if (png_ptr->interlaced)+
−
   {+
−
      if (!(png_ptr->transformations & PNG_INTERLACE))+
−
      {+
−
         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -+
−
            png_pass_ystart[0]) / png_pass_yinc[0];+
−
         png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -+
−
            png_pass_start[0]) / png_pass_inc[0];+
−
      }+
−
      else+
−
      {+
−
         png_ptr->num_rows = png_ptr->height;+
−
         png_ptr->usr_width = png_ptr->width;+
−
      }+
−
   }+
−
   else+
−
#endif+
−
   {+
−
      png_ptr->num_rows = png_ptr->height;+
−
      png_ptr->usr_width = png_ptr->width;+
−
   }+
−
   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;+
−
   png_ptr->zstream.next_out = png_ptr->zbuf;+
−
}+
−
+
−
/* Internal use only.  Called when finished processing a row of data. */+
−
void /* PRIVATE */+
−
png_write_finish_row(png_structp png_ptr)+
−
{+
−
#ifdef PNG_WRITE_INTERLACING_SUPPORTED+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */+
−
+
−
   /* Start of interlace block */+
−
   int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};+
−
+
−
   /* Offset to next interlace block */+
−
   int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};+
−
+
−
   /* Start of interlace block in the y direction */+
−
   int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};+
−
+
−
   /* Offset to next interlace block in the y direction */+
−
   int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};+
−
#endif+
−
#endif+
−
+
−
   int ret;+
−
+
−
   png_debug(1, "in png_write_finish_row");+
−
+
−
   /* Next row */+
−
   png_ptr->row_number++;+
−
+
−
   /* See if we are done */+
−
   if (png_ptr->row_number < png_ptr->num_rows)+
−
      return;+
−
+
−
#ifdef PNG_WRITE_INTERLACING_SUPPORTED+
−
   /* If interlaced, go to next pass */+
−
   if (png_ptr->interlaced)+
−
   {+
−
      png_ptr->row_number = 0;+
−
      if (png_ptr->transformations & PNG_INTERLACE)+
−
      {+
−
         png_ptr->pass++;+
−
      }+
−
      else+
−
      {+
−
         /* Loop until we find a non-zero width or height pass */+
−
         do+
−
         {+
−
            png_ptr->pass++;+
−
            if (png_ptr->pass >= 7)+
−
               break;+
−
            png_ptr->usr_width = (png_ptr->width ++
−
               png_pass_inc[png_ptr->pass] - 1 -+
−
               png_pass_start[png_ptr->pass]) /+
−
               png_pass_inc[png_ptr->pass];+
−
            png_ptr->num_rows = (png_ptr->height ++
−
               png_pass_yinc[png_ptr->pass] - 1 -+
−
               png_pass_ystart[png_ptr->pass]) /+
−
               png_pass_yinc[png_ptr->pass];+
−
            if (png_ptr->transformations & PNG_INTERLACE)+
−
               break;+
−
         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);+
−
+
−
      }+
−
+
−
      /* Reset the row above the image for the next pass */+
−
      if (png_ptr->pass < 7)+
−
      {+
−
         if (png_ptr->prev_row != NULL)+
−
            png_memset(png_ptr->prev_row, 0,+
−
               (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*+
−
               png_ptr->usr_bit_depth, png_ptr->width)) + 1);+
−
         return;+
−
      }+
−
   }+
−
#endif+
−
+
−
   /* If we get here, we've just written the last row, so we need+
−
      to flush the compressor */+
−
   do+
−
   {+
−
      /* Tell the compressor we are done */+
−
      ret = deflate(&png_ptr->zstream, Z_FINISH);+
−
      /* Check for an error */+
−
      if (ret == Z_OK)+
−
      {+
−
         /* Check to see if we need more room */+
−
         if (!(png_ptr->zstream.avail_out))+
−
         {+
−
            png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);+
−
            png_ptr->zstream.next_out = png_ptr->zbuf;+
−
            png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;+
−
         }+
−
      }+
−
      else if (ret != Z_STREAM_END)+
−
      {+
−
         if (png_ptr->zstream.msg != NULL)+
−
            png_error(png_ptr, png_ptr->zstream.msg);+
−
         else+
−
            png_error(png_ptr, "zlib error");+
−
      }+
−
   } while (ret != Z_STREAM_END);+
−
+
−
   /* Write any extra space */+
−
   if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)+
−
   {+
−
      png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -+
−
         png_ptr->zstream.avail_out);+
−
   }+
−
+
−
   deflateReset(&png_ptr->zstream);+
−
   png_ptr->zstream.data_type = Z_BINARY;+
−
}+
−
+
−
#if defined(PNG_WRITE_INTERLACING_SUPPORTED)+
−
/* Pick out the correct pixels for the interlace pass.+
−
 * The basic idea here is to go through the row with a source+
−
 * pointer and a destination pointer (sp and dp), and copy the+
−
 * correct pixels for the pass.  As the row gets compacted,+
−
 * sp will always be >= dp, so we should never overwrite anything.+
−
 * See the default: case for the easiest code to understand.+
−
 */+
−
void /* PRIVATE */+
−
png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)+
−
{+
−
#ifdef PNG_USE_LOCAL_ARRAYS+
−
   /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */+
−
+
−
   /* Start of interlace block */+
−
   int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};+
−
+
−
   /* Offset to next interlace block */+
−
   int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};+
−
#endif+
−
+
−
   png_debug(1, "in png_do_write_interlace");+
−
+
−
   /* We don't have to do anything on the last pass (6) */+
−
#if defined(PNG_USELESS_TESTS_SUPPORTED)+
−
   if (row != NULL && row_info != NULL && pass < 6)+
−
#else+
−
   if (pass < 6)+
−
#endif+
−
   {+
−
      /* Each pixel depth is handled separately */+
−
      switch (row_info->pixel_depth)+
−
      {+
−
         case 1:+
−
         {+
−
            png_bytep sp;+
−
            png_bytep dp;+
−
            int shift;+
−
            int d;+
−
            int value;+
−
            png_uint_32 i;+
−
            png_uint_32 row_width = row_info->width;+
−
+
−
            dp = row;+
−
            d = 0;+
−
            shift = 7;+
−
            for (i = png_pass_start[pass]; i < row_width;+
−
               i += png_pass_inc[pass])+
−
            {+
−
               sp = row + (png_size_t)(i >> 3);+
−
               value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;+
−
               d |= (value << shift);+
−
+
−
               if (shift == 0)+
−
               {+
−
                  shift = 7;+
−
                  *dp++ = (png_byte)d;+
−
                  d = 0;+
−
               }+
−
               else+
−
                  shift--;+
−
+
−
            }+
−
            if (shift != 7)+
−
               *dp = (png_byte)d;+
−
            break;+
−
         }+
−
         case 2:+
−
         {+
−
            png_bytep sp;+
−
            png_bytep dp;+
−
            int shift;+
−
            int d;+
−
            int value;+
−
            png_uint_32 i;+
−
            png_uint_32 row_width = row_info->width;+
−
+
−
            dp = row;+
−
            shift = 6;+
−
            d = 0;+
−
            for (i = png_pass_start[pass]; i < row_width;+
−
               i += png_pass_inc[pass])+
−
            {+
−
               sp = row + (png_size_t)(i >> 2);+
−
               value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;+
−
               d |= (value << shift);+
−
+
−
               if (shift == 0)+
−
               {+
−
                  shift = 6;+
−
                  *dp++ = (png_byte)d;+
−
                  d = 0;+
−
               }+
−
               else+
−
                  shift -= 2;+
−
            }+
−
            if (shift != 6)+
−
                   *dp = (png_byte)d;+
−
            break;+
−
         }+
−
         case 4:+
−
         {+
−
            png_bytep sp;+
−
            png_bytep dp;+
−
            int shift;+
−
            int d;+
−
            int value;+
−
            png_uint_32 i;+
−
            png_uint_32 row_width = row_info->width;+
−
+
−
            dp = row;+
−
            shift = 4;+
−
            d = 0;+
−
            for (i = png_pass_start[pass]; i < row_width;+
−
               i += png_pass_inc[pass])+
−
            {+
−
               sp = row + (png_size_t)(i >> 1);+
−
               value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;+
−
               d |= (value << shift);+
−
+
−
               if (shift == 0)+
−
               {+
−
                  shift = 4;+
−
                  *dp++ = (png_byte)d;+
−
                  d = 0;+
−
               }+
−
               else+
−
                  shift -= 4;+
−
            }+
−
            if (shift != 4)+
−
               *dp = (png_byte)d;+
−
            break;+
−
         }+
−
         default:+
−
         {+
−
            png_bytep sp;+
−
            png_bytep dp;+
−
            png_uint_32 i;+
−
            png_uint_32 row_width = row_info->width;+
−
            png_size_t pixel_bytes;+
−
+
−
            /* Start at the beginning */+
−
            dp = row;+
−
            /* Find out how many bytes each pixel takes up */+
−
            pixel_bytes = (row_info->pixel_depth >> 3);+
−
            /* Loop through the row, only looking at the pixels that+
−
               matter */+
−
            for (i = png_pass_start[pass]; i < row_width;+
−
               i += png_pass_inc[pass])+
−
            {+
−
               /* Find out where the original pixel is */+
−
               sp = row + (png_size_t)i * pixel_bytes;+
−
               /* Move the pixel */+
−
               if (dp != sp)+
−
                  png_memcpy(dp, sp, pixel_bytes);+
−
               /* Next pixel */+
−
               dp += pixel_bytes;+
−
            }+
−
            break;+
−
         }+
−
      }+
−
      /* Set new row width */+
−
      row_info->width = (row_info->width ++
−
         png_pass_inc[pass] - 1 -+
−
         png_pass_start[pass]) /+
−
         png_pass_inc[pass];+
−
         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,+
−
            row_info->width);+
−
   }+
−
}+
−
#endif+
−
+
−
/* This filters the row, chooses which filter to use, if it has not already+
−
 * been specified by the application, and then writes the row out with the+
−
 * chosen filter.+
−
 */+
−
#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)+
−
#define PNG_HISHIFT 10+
−
#define PNG_LOMASK ((png_uint_32)0xffffL)+
−
#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))+
−
void /* PRIVATE */+
−
png_write_find_filter(png_structp png_ptr, png_row_infop row_info)+
−
{+
−
   png_bytep best_row;+
−
#ifndef PNG_NO_WRITE_FILTER+
−
   png_bytep prev_row, row_buf;+
−
   png_uint_32 mins, bpp;+
−
   png_byte filter_to_do = png_ptr->do_filter;+
−
   png_uint_32 row_bytes = row_info->rowbytes;+
−
#ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED+
−
   int num_p_filters = (int)png_ptr->num_prev_filters;+
−
#endif +
−
+
−
   png_debug(1, "in png_write_find_filter");+
−
+
−
   /* Find out how many bytes offset each pixel is */+
−
   bpp = (row_info->pixel_depth + 7) >> 3;+
−
+
−
   prev_row = png_ptr->prev_row;+
−
#endif+
−
   best_row = png_ptr->row_buf;+
−
#ifndef PNG_NO_WRITE_FILTER+
−
   row_buf = best_row;+
−
   mins = PNG_MAXSUM;+
−
+
−
   /* The prediction method we use is to find which method provides the+
−
    * smallest value when summing the absolute values of the distances+
−
    * from zero, using anything >= 128 as negative numbers.  This is known+
−
    * as the "minimum sum of absolute differences" heuristic.  Other+
−
    * heuristics are the "weighted minimum sum of absolute differences"+
−
    * (experimental and can in theory improve compression), and the "zlib+
−
    * predictive" method (not implemented yet), which does test compressions+
−
    * of lines using different filter methods, and then chooses the+
−
    * (series of) filter(s) that give minimum compressed data size (VERY+
−
    * computationally expensive).+
−
    *+
−
    * GRR 980525:  consider also+
−
    *   (1) minimum sum of absolute differences from running average (i.e.,+
−
    *       keep running sum of non-absolute differences & count of bytes)+
−
    *       [track dispersion, too?  restart average if dispersion too large?]+
−
    *  (1b) minimum sum of absolute differences from sliding average, probably+
−
    *       with window size <= deflate window (usually 32K)+
−
    *   (2) minimum sum of squared differences from zero or running average+
−
    *       (i.e., ~ root-mean-square approach)+
−
    */+
−
+
−
+
−
   /* We don't need to test the 'no filter' case if this is the only filter+
−
    * that has been chosen, as it doesn't actually do anything to the data.+
−
    */+
−
   if ((filter_to_do & PNG_FILTER_NONE) &&+
−
       filter_to_do != PNG_FILTER_NONE)+
−
   {+
−
      png_bytep rp;+
−
      png_uint_32 sum = 0;+
−
      png_uint_32 i;+
−
      int v;+
−
+
−
      for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)+
−
      {+
−
         v = *rp;+
−
         sum += (v < 128) ? v : 256 - v;+
−
      }+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         png_uint_32 sumhi, sumlo;+
−
         int j;+
−
         sumlo = sum & PNG_LOMASK;+
−
         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */+
−
+
−
         /* Reduce the sum if we match any of the previous rows */+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)+
−
            {+
−
               sumlo = (sumlo * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               sumhi = (sumhi * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         /* Factor in the cost of this filter (this is here for completeness,+
−
          * but it makes no sense to have a "cost" for the NONE filter, as+
−
          * it has the minimum possible computational cost - none).+
−
          */+
−
         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>+
−
            PNG_COST_SHIFT;+
−
         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (sumhi > PNG_HIMASK)+
−
            sum = PNG_MAXSUM;+
−
         else+
−
            sum = (sumhi << PNG_HISHIFT) + sumlo;+
−
      }+
−
#endif+
−
      mins = sum;+
−
   }+
−
+
−
   /* Sub filter */+
−
   if (filter_to_do == PNG_FILTER_SUB)+
−
   /* It's the only filter so no testing is needed */+
−
   {+
−
      png_bytep rp, lp, dp;+
−
      png_uint_32 i;+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;+
−
           i++, rp++, dp++)+
−
      {+
−
         *dp = *rp;+
−
      }+
−
      for (lp = row_buf + 1; i < row_bytes;+
−
         i++, rp++, lp++, dp++)+
−
      {+
−
         *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);+
−
      }+
−
      best_row = png_ptr->sub_row;+
−
   }+
−
+
−
   else if (filter_to_do & PNG_FILTER_SUB)+
−
   {+
−
      png_bytep rp, dp, lp;+
−
      png_uint_32 sum = 0, lmins = mins;+
−
      png_uint_32 i;+
−
      int v;+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      /* We temporarily increase the "minimum sum" by the factor we+
−
       * would reduce the sum of this filter, so that we can do the+
−
       * early exit comparison without scaling the sum each time.+
−
       */+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 lmhi, lmlo;+
−
         lmlo = lmins & PNG_LOMASK;+
−
         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)+
−
            {+
−
               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>+
−
            PNG_COST_SHIFT;+
−
         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (lmhi > PNG_HIMASK)+
−
            lmins = PNG_MAXSUM;+
−
         else+
−
            lmins = (lmhi << PNG_HISHIFT) + lmlo;+
−
      }+
−
#endif+
−
+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;+
−
           i++, rp++, dp++)+
−
      {+
−
         v = *dp = *rp;+
−
+
−
         sum += (v < 128) ? v : 256 - v;+
−
      }+
−
      for (lp = row_buf + 1; i < row_bytes;+
−
         i++, rp++, lp++, dp++)+
−
      {+
−
         v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);+
−
+
−
         sum += (v < 128) ? v : 256 - v;+
−
+
−
         if (sum > lmins)  /* We are already worse, don't continue. */+
−
            break;+
−
      }+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 sumhi, sumlo;+
−
         sumlo = sum & PNG_LOMASK;+
−
         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)+
−
            {+
−
               sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>+
−
            PNG_COST_SHIFT;+
−
         sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (sumhi > PNG_HIMASK)+
−
            sum = PNG_MAXSUM;+
−
         else+
−
            sum = (sumhi << PNG_HISHIFT) + sumlo;+
−
      }+
−
#endif+
−
+
−
      if (sum < mins)+
−
      {+
−
         mins = sum;+
−
         best_row = png_ptr->sub_row;+
−
      }+
−
   }+
−
+
−
   /* Up filter */+
−
   if (filter_to_do == PNG_FILTER_UP)+
−
   {+
−
      png_bytep rp, dp, pp;+
−
      png_uint_32 i;+
−
+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,+
−
           pp = prev_row + 1; i < row_bytes;+
−
           i++, rp++, pp++, dp++)+
−
      {+
−
         *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);+
−
      }+
−
      best_row = png_ptr->up_row;+
−
   }+
−
+
−
   else if (filter_to_do & PNG_FILTER_UP)+
−
   {+
−
      png_bytep rp, dp, pp;+
−
      png_uint_32 sum = 0, lmins = mins;+
−
      png_uint_32 i;+
−
      int v;+
−
+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 lmhi, lmlo;+
−
         lmlo = lmins & PNG_LOMASK;+
−
         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)+
−
            {+
−
               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>+
−
            PNG_COST_SHIFT;+
−
         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (lmhi > PNG_HIMASK)+
−
            lmins = PNG_MAXSUM;+
−
         else+
−
            lmins = (lmhi << PNG_HISHIFT) + lmlo;+
−
      }+
−
#endif+
−
+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,+
−
           pp = prev_row + 1; i < row_bytes; i++)+
−
      {+
−
         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);+
−
+
−
         sum += (v < 128) ? v : 256 - v;+
−
+
−
         if (sum > lmins)  /* We are already worse, don't continue. */+
−
            break;+
−
      }+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 sumhi, sumlo;+
−
         sumlo = sum & PNG_LOMASK;+
−
         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)+
−
            {+
−
               sumlo = (sumlo * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               sumhi = (sumhi * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>+
−
            PNG_COST_SHIFT;+
−
         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (sumhi > PNG_HIMASK)+
−
            sum = PNG_MAXSUM;+
−
         else+
−
            sum = (sumhi << PNG_HISHIFT) + sumlo;+
−
      }+
−
#endif+
−
+
−
      if (sum < mins)+
−
      {+
−
         mins = sum;+
−
         best_row = png_ptr->up_row;+
−
      }+
−
   }+
−
+
−
   /* Avg filter */+
−
   if (filter_to_do == PNG_FILTER_AVG)+
−
   {+
−
      png_bytep rp, dp, pp, lp;+
−
      png_uint_32 i;+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,+
−
           pp = prev_row + 1; i < bpp; i++)+
−
      {+
−
         *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);+
−
      }+
−
      for (lp = row_buf + 1; i < row_bytes; i++)+
−
      {+
−
         *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))+
−
                 & 0xff);+
−
      }+
−
      best_row = png_ptr->avg_row;+
−
   }+
−
+
−
   else if (filter_to_do & PNG_FILTER_AVG)+
−
   {+
−
      png_bytep rp, dp, pp, lp;+
−
      png_uint_32 sum = 0, lmins = mins;+
−
      png_uint_32 i;+
−
      int v;+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 lmhi, lmlo;+
−
         lmlo = lmins & PNG_LOMASK;+
−
         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)+
−
            {+
−
               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>+
−
            PNG_COST_SHIFT;+
−
         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (lmhi > PNG_HIMASK)+
−
            lmins = PNG_MAXSUM;+
−
         else+
−
            lmins = (lmhi << PNG_HISHIFT) + lmlo;+
−
      }+
−
#endif+
−
+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,+
−
           pp = prev_row + 1; i < bpp; i++)+
−
      {+
−
         v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);+
−
+
−
         sum += (v < 128) ? v : 256 - v;+
−
      }+
−
      for (lp = row_buf + 1; i < row_bytes; i++)+
−
      {+
−
         v = *dp++ =+
−
          (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);+
−
+
−
         sum += (v < 128) ? v : 256 - v;+
−
+
−
         if (sum > lmins)  /* We are already worse, don't continue. */+
−
            break;+
−
      }+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 sumhi, sumlo;+
−
         sumlo = sum & PNG_LOMASK;+
−
         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)+
−
            {+
−
               sumlo = (sumlo * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               sumhi = (sumhi * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>+
−
            PNG_COST_SHIFT;+
−
         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (sumhi > PNG_HIMASK)+
−
            sum = PNG_MAXSUM;+
−
         else+
−
            sum = (sumhi << PNG_HISHIFT) + sumlo;+
−
      }+
−
#endif+
−
+
−
      if (sum < mins)+
−
      {+
−
         mins = sum;+
−
         best_row = png_ptr->avg_row;+
−
      }+
−
   }+
−
+
−
   /* Paeth filter */+
−
   if (filter_to_do == PNG_FILTER_PAETH)+
−
   {+
−
      png_bytep rp, dp, pp, cp, lp;+
−
      png_uint_32 i;+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,+
−
           pp = prev_row + 1; i < bpp; i++)+
−
      {+
−
         *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);+
−
      }+
−
+
−
      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)+
−
      {+
−
         int a, b, c, pa, pb, pc, p;+
−
+
−
         b = *pp++;+
−
         c = *cp++;+
−
         a = *lp++;+
−
+
−
         p = b - c;+
−
         pc = a - c;+
−
+
−
#ifdef PNG_USE_ABS+
−
         pa = abs(p);+
−
         pb = abs(pc);+
−
         pc = abs(p + pc);+
−
#else+
−
         pa = p < 0 ? -p : p;+
−
         pb = pc < 0 ? -pc : pc;+
−
         pc = (p + pc) < 0 ? -(p + pc) : p + pc;+
−
#endif+
−
+
−
         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;+
−
+
−
         *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);+
−
      }+
−
      best_row = png_ptr->paeth_row;+
−
   }+
−
+
−
   else if (filter_to_do & PNG_FILTER_PAETH)+
−
   {+
−
      png_bytep rp, dp, pp, cp, lp;+
−
      png_uint_32 sum = 0, lmins = mins;+
−
      png_uint_32 i;+
−
      int v;+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 lmhi, lmlo;+
−
         lmlo = lmins & PNG_LOMASK;+
−
         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)+
−
            {+
−
               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>+
−
            PNG_COST_SHIFT;+
−
         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (lmhi > PNG_HIMASK)+
−
            lmins = PNG_MAXSUM;+
−
         else+
−
            lmins = (lmhi << PNG_HISHIFT) + lmlo;+
−
      }+
−
#endif+
−
+
−
      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,+
−
           pp = prev_row + 1; i < bpp; i++)+
−
      {+
−
         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);+
−
+
−
         sum += (v < 128) ? v : 256 - v;+
−
      }+
−
+
−
      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)+
−
      {+
−
         int a, b, c, pa, pb, pc, p;+
−
+
−
         b = *pp++;+
−
         c = *cp++;+
−
         a = *lp++;+
−
+
−
#ifndef PNG_SLOW_PAETH+
−
         p = b - c;+
−
         pc = a - c;+
−
#ifdef PNG_USE_ABS+
−
         pa = abs(p);+
−
         pb = abs(pc);+
−
         pc = abs(p + pc);+
−
#else+
−
         pa = p < 0 ? -p : p;+
−
         pb = pc < 0 ? -pc : pc;+
−
         pc = (p + pc) < 0 ? -(p + pc) : p + pc;+
−
#endif+
−
         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;+
−
#else /* PNG_SLOW_PAETH */+
−
         p = a + b - c;+
−
         pa = abs(p - a);+
−
         pb = abs(p - b);+
−
         pc = abs(p - c);+
−
         if (pa <= pb && pa <= pc)+
−
            p = a;+
−
         else if (pb <= pc)+
−
            p = b;+
−
         else+
−
            p = c;+
−
#endif /* PNG_SLOW_PAETH */+
−
+
−
         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);+
−
+
−
         sum += (v < 128) ? v : 256 - v;+
−
+
−
         if (sum > lmins)  /* We are already worse, don't continue. */+
−
            break;+
−
      }+
−
+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)+
−
      {+
−
         int j;+
−
         png_uint_32 sumhi, sumlo;+
−
         sumlo = sum & PNG_LOMASK;+
−
         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;+
−
+
−
         for (j = 0; j < num_p_filters; j++)+
−
         {+
−
            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)+
−
            {+
−
               sumlo = (sumlo * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
               sumhi = (sumhi * png_ptr->filter_weights[j]) >>+
−
                  PNG_WEIGHT_SHIFT;+
−
            }+
−
         }+
−
+
−
         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>+
−
            PNG_COST_SHIFT;+
−
         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>+
−
            PNG_COST_SHIFT;+
−
+
−
         if (sumhi > PNG_HIMASK)+
−
            sum = PNG_MAXSUM;+
−
         else+
−
            sum = (sumhi << PNG_HISHIFT) + sumlo;+
−
      }+
−
#endif+
−
+
−
      if (sum < mins)+
−
      {+
−
         best_row = png_ptr->paeth_row;+
−
      }+
−
   }+
−
#endif /* PNG_NO_WRITE_FILTER */+
−
   /* Do the actual writing of the filtered row data from the chosen filter. */+
−
+
−
   png_write_filtered_row(png_ptr, best_row);+
−
+
−
#ifndef PNG_NO_WRITE_FILTER+
−
#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)+
−
   /* Save the type of filter we picked this time for future calculations */+
−
   if (png_ptr->num_prev_filters > 0)+
−
   {+
−
      int j;+
−
      for (j = 1; j < num_p_filters; j++)+
−
      {+
−
         png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];+
−
      }+
−
      png_ptr->prev_filters[j] = best_row[0];+
−
   }+
−
#endif+
−
#endif /* PNG_NO_WRITE_FILTER */+
−
}+
−
+
−
+
−
/* Do the actual writing of a previously filtered row. */+
−
void /* PRIVATE */+
−
png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)+
−
{+
−
   png_debug(1, "in png_write_filtered_row");+
−
+
−
   png_debug1(2, "filter = %d", filtered_row[0]);+
−
   /* Set up the zlib input buffer */+
−
+
−
   png_ptr->zstream.next_in = filtered_row;+
−
   png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;+
−
   /* Repeat until we have compressed all the data */+
−
   do+
−
   {+
−
      int ret; /* Return of zlib */+
−
+
−
      /* Compress the data */+
−
      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);+
−
      /* Check for compression errors */+
−
      if (ret != Z_OK)+
−
      {+
−
         if (png_ptr->zstream.msg != NULL)+
−
            png_error(png_ptr, png_ptr->zstream.msg);+
−
         else+
−
            png_error(png_ptr, "zlib error");+
−
      }+
−
+
−
      /* See if it is time to write another IDAT */+
−
      if (!(png_ptr->zstream.avail_out))+
−
      {+
−
         /* Write the IDAT and reset the zlib output buffer */+
−
         png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);+
−
         png_ptr->zstream.next_out = png_ptr->zbuf;+
−
         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;+
−
      }+
−
   /* Repeat until all data has been compressed */+
−
   } while (png_ptr->zstream.avail_in);+
−
+
−
   /* Swap the current and previous rows */+
−
   if (png_ptr->prev_row != NULL)+
−
   {+
−
      png_bytep tptr;+
−
+
−
      tptr = png_ptr->prev_row;+
−
      png_ptr->prev_row = png_ptr->row_buf;+
−
      png_ptr->row_buf = tptr;+
−
   }+
−
+
−
   /* Finish row - updates counters and flushes zlib if last row */+
−
   png_write_finish_row(png_ptr);+
−
+
−
#if defined(PNG_WRITE_FLUSH_SUPPORTED)+
−
   png_ptr->flush_rows++;+
−
+
−
   if (png_ptr->flush_dist > 0 &&+
−
       png_ptr->flush_rows >= png_ptr->flush_dist)+
−
   {+
−
      png_write_flush(png_ptr);+
−
   }+
−
#endif+
−
}+
−
#endif /* PNG_WRITE_SUPPORTED */+
−