pngwrite.c

hl2 source code. Do not use it illegal.

/* pngwrite.c - general routines to write a PNG file
 *
 * libpng 1.0.3 - January 14, 1999
 * For conditions of distribution and use, see copyright notice in png.h
 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
 * Copyright (c) 1996, 1997 Andreas Dilger
 * Copyright (c) 1998, 1999 Glenn Randers-Pehrson
 */

/* get internal access to png.h */
#define PNG_INTERNAL
#include "png.h"

/* Writes all the PNG information.  This is the suggested way to use the
 * library.  If you have a new chunk to add, make a function to write it,
 * and put it in the correct location here.  If you want the chunk written
 * after the image data, put it in png_write_end().  I strongly encourage
 * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
 * the chunk, as that will keep the code from breaking if you want to just
 * write a plain PNG file.  If you have long comments, I suggest writing
 * them in png_write_end(), and compressing them.
 */
void
png_write_info(png_structp png_ptr, png_infop info_ptr)
{
#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
   int i;
#endif

   png_debug(1, "in png_write_info\n");
   png_write_sig(png_ptr); /* write PNG signature */
   /* write IHDR information. */
   png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
      info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
      info_ptr->filter_type,
#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
      info_ptr->interlace_type);
#else
      0);
#endif
   /* the rest of these check to see if the valid field has the appropriate
      flag set, and if it does, writes the chunk. */
#if defined(PNG_WRITE_gAMA_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_gAMA)
      png_write_gAMA(png_ptr, info_ptr->gamma);
#endif
#if defined(PNG_WRITE_sRGB_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_sRGB)
      png_write_sRGB(png_ptr, (int)info_ptr->srgb_intent);
#endif
#if defined(PNG_WRITE_sBIT_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_sBIT)
      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
#endif
#if defined(PNG_WRITE_cHRM_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_cHRM)
      png_write_cHRM(png_ptr,
         info_ptr->x_white, info_ptr->y_white,
         info_ptr->x_red, info_ptr->y_red,
         info_ptr->x_green, info_ptr->y_green,
         info_ptr->x_blue, info_ptr->y_blue);
#endif
   if (info_ptr->valid & PNG_INFO_PLTE)
      png_write_PLTE(png_ptr, info_ptr->palette,
         (png_uint_32)info_ptr->num_palette);
   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
      png_error(png_ptr, "Valid palette required for paletted images\n");

#if defined(PNG_WRITE_tRNS_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_tRNS)
      {
#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
         /* invert the alpha channel (in tRNS) */
         if (png_ptr->transformations & PNG_INVERT_ALPHA &&
            info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
         {
            int j;
            for (j=0; j<(int)info_ptr->num_trans; j++)
               info_ptr->trans[j] = 255 - info_ptr->trans[j];
         }
#endif
      png_write_tRNS(png_ptr, info_ptr->trans, &(info_ptr->trans_values),
         info_ptr->num_trans, info_ptr->color_type);
      }
#endif
#if defined(PNG_WRITE_bKGD_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_bKGD)
      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
#endif
#if defined(PNG_WRITE_hIST_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_hIST)
      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
#endif
#if defined(PNG_WRITE_oFFs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_oFFs)
      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
         info_ptr->offset_unit_type);
#endif
#if defined(PNG_WRITE_pCAL_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_pCAL)
      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
         info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
         info_ptr->pcal_units, info_ptr->pcal_params);
#endif
#if defined(PNG_WRITE_pHYs_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_pHYs)
      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
         info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
#endif
#if defined(PNG_WRITE_tIME_SUPPORTED)
   if (info_ptr->valid & PNG_INFO_tIME)
   {
      png_write_tIME(png_ptr, &(info_ptr->mod_time));
      png_ptr->flags |= PNG_FLAG_WROTE_tIME;
   }
#endif
#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
   /* Check to see if we need to write text chunks */
   for (i = 0; i < info_ptr->num_text; i++)
   {
      png_debug2(2, "Writing header text chunk %d, type %d\n", i,
         info_ptr->text[i].compression);
      /* If we want a compressed text chunk */
      if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
      {
#if defined(PNG_WRITE_zTXt_SUPPORTED)
         /* write compressed chunk */
         png_write_zTXt(png_ptr, info_ptr->text[i].key,
            info_ptr->text[i].text, info_ptr->text[i].text_length,
            info_ptr->text[i].compression);
#else
         png_warning(png_ptr, "Unable to write compressed text\n");
#endif
         /* Mark this chunk as written */
         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
      }
      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
      {
#if defined(PNG_WRITE_tEXt_SUPPORTED)
         /* write uncompressed chunk */
         png_write_tEXt(png_ptr, info_ptr->text[i].key,
            info_ptr->text[i].text, info_ptr->text[i].text_length);
#else
         png_warning(png_ptr, "Unable to write uncompressed text\n");
#endif
         /* Mark this chunk as written */
         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
      }
   }
#endif
}

/* Writes the end of the PNG file.  If you don't want to write comments or
 * time information, you can pass NULL for info.  If you already wrote these
 * in png_write_info(), do not write them again here.  If you have long
 * comments, I suggest writing them here, and compressing them.
 */
void
png_write_end(png_structp png_ptr, png_infop info_ptr)
{
   png_debug(1, "in png_write_end\n");
   if (!(png_ptr->mode & PNG_HAVE_IDAT))
      png_error(png_ptr, "No IDATs written into file");

   /* see if user wants us to write information chunks */
   if (info_ptr != NULL)
   {
#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
      int i; /* local index variable */
#endif
#if defined(PNG_WRITE_tIME_SUPPORTED)
      /* check to see if user has supplied a time chunk */
      if (info_ptr->valid & PNG_INFO_tIME &&
         !(png_ptr->flags & PNG_FLAG_WROTE_tIME))
         png_write_tIME(png_ptr, &(info_ptr->mod_time));
#endif
#if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
      /* loop through comment chunks */
      for (i = 0; i < info_ptr->num_text; i++)
      {
         png_debug2(2, "Writing trailer text chunk %d, type %d\n", i,
            info_ptr->text[i].compression);
         if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
         {
#if defined(PNG_WRITE_zTXt_SUPPORTED)
            /* write compressed chunk */
            png_write_zTXt(png_ptr, info_ptr->text[i].key,
               info_ptr->text[i].text, info_ptr->text[i].text_length,
               info_ptr->text[i].compression);
#else
            png_warning(png_ptr, "Unable to write compressed text\n");
#endif
            /* Mark this chunk as written */
            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
         }
         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
         {
#if defined(PNG_WRITE_tEXt_SUPPORTED)
            /* write uncompressed chunk */
            png_write_tEXt(png_ptr, info_ptr->text[i].key,
               info_ptr->text[i].text, info_ptr->text[i].text_length);
#else
            png_warning(png_ptr, "Unable to write uncompressed text\n");
#endif

            /* Mark this chunk as written */
            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
         }
      }
#endif
   }

   png_ptr->mode |= PNG_AFTER_IDAT;

   /* write end of PNG file */
   png_write_IEND(png_ptr);
}

#if defined(PNG_WRITE_tIME_SUPPORTED)
void
png_convert_from_struct_tm(png_timep ptime, struct tm FAR * ttime)
{
   png_debug(1, "in png_convert_from_struct_tm\n");
   ptime->year = (png_uint_16)(1900 + ttime->tm_year);
   ptime->month = (png_byte)(ttime->tm_mon + 1);
   ptime->day = (png_byte)ttime->tm_mday;
   ptime->hour = (png_byte)ttime->tm_hour;
   ptime->minute = (png_byte)ttime->tm_min;
   ptime->second = (png_byte)ttime->tm_sec;
}

void
png_convert_from_time_t(png_timep ptime, time_t ttime)
{
   struct tm *tbuf;

   png_debug(1, "in png_convert_from_time_t\n");
   tbuf = gmtime(&ttime);
   png_convert_from_struct_tm(ptime, tbuf);
}
#endif

/* Initialize png_ptr structure, and allocate any memory needed */
png_structp
png_create_write_struct(png_const_charp user_png_ver, png_voidp error_ptr,
   png_error_ptr error_fn, png_error_ptr warn_fn)
{
#ifdef PNG_USER_MEM_SUPPORTED
   return (png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
      warn_fn, NULL, NULL, NULL));
}

/* Alternate initialize png_ptr structure, and allocate any memory needed */
png_structp
png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
   png_malloc_ptr malloc_fn, png_free_ptr free_fn)
{
#endif /* PNG_USER_MEM_SUPPORTED */
   png_structp png_ptr;
#ifdef USE_FAR_KEYWORD
   jmp_buf jmpbuf;
#endif
   png_debug(1, "in png_create_write_struct\n");
#ifdef PNG_USER_MEM_SUPPORTED
   if ((png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
      (png_malloc_ptr)malloc_fn)) == NULL)
#else
   if ((png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG)) == NULL)
#endif /* PNG_USER_MEM_SUPPORTED */
   {
      return ((png_structp)NULL);
   }
#ifdef USE_FAR_KEYWORD
   if (setjmp(jmpbuf))
#else
   if (setjmp(png_ptr->jmpbuf))
#endif
   {
      png_free(png_ptr, png_ptr->zbuf);
      png_destroy_struct(png_ptr);
      return ((png_structp)NULL);
   }
#ifdef USE_FAR_KEYWORD
   png_memcpy(png_ptr->jmpbuf,jmpbuf,sizeof(jmp_buf));
#endif
#ifdef PNG_USER_MEM_SUPPORTED
   png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
#endif /* PNG_USER_MEM_SUPPORTED */
   png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);

   /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
    * we must recompile any applications that use any older library version.
    * For versions after libpng 1.0, we will be compatible, so we need
    * only check the first digit.
    */
   if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
       (png_libpng_ver[0] == '0' && user_png_ver[2] < '9'))
   {
      png_error(png_ptr,
         "Incompatible libpng version in application and library");
   }

   /* initialize zbuf - compression buffer */
   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
   png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
      (png_uint_32)png_ptr->zbuf_size);

   png_set_write_fn(png_ptr, NULL, NULL, NULL);

#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
   png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
      1, NULL, NULL);
#endif

   return ((png_structp)png_ptr);
}

/* Initialize png_ptr structure, and allocate any memory needed */
void
png_write_init(png_structp png_ptr)
{
   jmp_buf tmp_jmp; /* to save current jump buffer */

   png_debug(1, "in png_write_init\n");
   /* save jump buffer and error functions */
   png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));

   /* reset all variables to 0 */
   png_memset(png_ptr, 0, sizeof (png_struct));

   /* restore jump buffer */
   png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));