jni/sdl_image/IMG_png.c

/*
    SDL_image:  An example image loading library for use with SDL
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#if !defined(__APPLE__) || defined(SDL_IMAGE_USE_COMMON_BACKEND)

/* This is a PNG image file loading framework */

#include <stdlib.h>
#include <stdio.h>

#include "SDL_image.h"

#ifdef LOAD_PNG

/*=============================================================================
        File: SDL_png.c
     Purpose: A PNG loader and saver for the SDL library
    Revision:
  Created by: Philippe Lavoie          (2 November 1998)
              lavoie@zeus.genie.uottawa.ca
 Modified by:

 Copyright notice:
          Copyright (C) 1998 Philippe Lavoie

          This library is free software; you can redistribute it and/or
          modify it under the terms of the GNU Library General Public
          License as published by the Free Software Foundation; either
          version 2 of the License, or (at your option) any later version.

          This library is distributed in the hope that it will be useful,
          but WITHOUT ANY WARRANTY; without even the implied warranty of
          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
          Library General Public License for more details.

          You should have received a copy of the GNU Library General Public
          License along with this library; if not, write to the Free
          Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    Comments: The load and save routine are basically the ones you can find
             in the example.c file from the libpng distribution.

  Changes:
    5/17/99 - Modified to use the new SDL data sources - Sam Lantinga

=============================================================================*/

#include "SDL_endian.h"

#ifdef macintosh
#define MACOS
#endif
#include <png.h>


static struct {
 int loaded;
 void *handle;
 png_infop (*png_create_info_struct) (png_structp png_ptr);
 png_structp (*png_create_read_struct) (png_const_charp user_png_ver, png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warn_fn);
 void (*png_destroy_read_struct) (png_structpp png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr);
 png_uint_32 (*png_get_IHDR) (png_structp png_ptr, png_infop info_ptr, png_uint_32 *width, png_uint_32 *height, int *bit_depth, int *color_type, int *interlace_method, int *compression_method, int *filter_method);
 png_voidp (*png_get_io_ptr) (png_structp png_ptr);
 png_uint_32 (*png_get_tRNS) (png_structp png_ptr, png_infop info_ptr, png_bytep *trans, int *num_trans, png_color_16p *trans_values);
 png_uint_32 (*png_get_valid) (png_structp png_ptr, png_infop info_ptr, png_uint_32 flag);
 void (*png_read_image) (png_structp png_ptr, png_bytepp image);
 void (*png_read_info) (png_structp png_ptr, png_infop info_ptr);
 void (*png_read_update_info) (png_structp png_ptr, png_infop info_ptr);
 void (*png_set_expand) (png_structp png_ptr);
 void (*png_set_gray_to_rgb) (png_structp png_ptr);
 void (*png_set_packing) (png_structp png_ptr);
 void (*png_set_read_fn) (png_structp png_ptr, png_voidp io_ptr, png_rw_ptr read_data_fn);
 void (*png_set_strip_16) (png_structp png_ptr);
 int (*png_sig_cmp) (png_bytep sig, png_size_t start, png_size_t num_to_check);
} lib;

#ifdef LOAD_PNG_DYNAMIC
int IMG_InitPNG()
{
 if ( lib.loaded == 0 ) {
   lib.handle = SDL_LoadObject(LOAD_PNG_DYNAMIC);
   if ( lib.handle == NULL ) {
     return -1;
   }
   lib.png_create_info_struct =
     (png_infop (*) (png_structp))
     SDL_LoadFunction(lib.handle, "png_create_info_struct");
   if ( lib.png_create_info_struct == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_create_read_struct =
     (png_structp (*) (png_const_charp, png_voidp, png_error_ptr, png_error_ptr))
     SDL_LoadFunction(lib.handle, "png_create_read_struct");
   if ( lib.png_create_read_struct == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_destroy_read_struct =
     (void (*) (png_structpp, png_infopp, png_infopp))
     SDL_LoadFunction(lib.handle, "png_destroy_read_struct");
   if ( lib.png_destroy_read_struct == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_get_IHDR =
     (png_uint_32 (*) (png_structp, png_infop, png_uint_32 *, png_uint_32 *, int *, int *, int *, int *, int *))
     SDL_LoadFunction(lib.handle, "png_get_IHDR");
   if ( lib.png_get_IHDR == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_get_io_ptr =
     (png_voidp (*) (png_structp))
     SDL_LoadFunction(lib.handle, "png_get_io_ptr");
   if ( lib.png_get_io_ptr == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_get_tRNS =
     (png_uint_32 (*) (png_structp, png_infop, png_bytep *, int *, png_color_16p *))
     SDL_LoadFunction(lib.handle, "png_get_tRNS");
   if ( lib.png_get_tRNS == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_get_valid =
     (png_uint_32 (*) (png_structp, png_infop, png_uint_32))
     SDL_LoadFunction(lib.handle, "png_get_valid");
   if ( lib.png_get_valid == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_read_image =
     (void (*) (png_structp, png_bytepp))
     SDL_LoadFunction(lib.handle, "png_read_image");
   if ( lib.png_read_image == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_read_info =
     (void (*) (png_structp, png_infop))
     SDL_LoadFunction(lib.handle, "png_read_info");
   if ( lib.png_read_info == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_read_update_info =
     (void (*) (png_structp, png_infop))
     SDL_LoadFunction(lib.handle, "png_read_update_info");
   if ( lib.png_read_update_info == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_set_expand =
     (void (*) (png_structp))
     SDL_LoadFunction(lib.handle, "png_set_expand");
   if ( lib.png_set_expand == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_set_gray_to_rgb =
     (void (*) (png_structp))
     SDL_LoadFunction(lib.handle, "png_set_gray_to_rgb");
   if ( lib.png_set_gray_to_rgb == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_set_packing =
     (void (*) (png_structp))
     SDL_LoadFunction(lib.handle, "png_set_packing");
   if ( lib.png_set_packing == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_set_read_fn =
     (void (*) (png_structp, png_voidp, png_rw_ptr))
     SDL_LoadFunction(lib.handle, "png_set_read_fn");
   if ( lib.png_set_read_fn == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_set_strip_16 =
     (void (*) (png_structp))
     SDL_LoadFunction(lib.handle, "png_set_strip_16");
   if ( lib.png_set_strip_16 == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
   lib.png_sig_cmp =
     (int (*) (png_bytep, png_size_t, png_size_t))
     SDL_LoadFunction(lib.handle, "png_sig_cmp");
   if ( lib.png_sig_cmp == NULL ) {
     SDL_UnloadObject(lib.handle);
     return -1;
   }
 }
 ++lib.loaded;

 return 0;
}
void IMG_QuitPNG()
{
 if ( lib.loaded == 0 ) {
   return;
 }
 if ( lib.loaded == 1 ) {
   SDL_UnloadObject(lib.handle);
 }
 --lib.loaded;
}
#else
int IMG_InitPNG()
{
 if ( lib.loaded == 0 ) {
   lib.png_create_info_struct = png_create_info_struct;
   lib.png_create_read_struct = png_create_read_struct;
   lib.png_destroy_read_struct = png_destroy_read_struct;
   lib.png_get_IHDR = png_get_IHDR;
   lib.png_get_io_ptr = png_get_io_ptr;
   lib.png_get_tRNS = png_get_tRNS;
   lib.png_get_valid = png_get_valid;
   lib.png_read_image = png_read_image;
   lib.png_read_info = png_read_info;
   lib.png_read_update_info = png_read_update_info;
   lib.png_set_expand = png_set_expand;
   lib.png_set_gray_to_rgb = png_set_gray_to_rgb;
   lib.png_set_packing = png_set_packing;
   lib.png_set_read_fn = png_set_read_fn;
   lib.png_set_strip_16 = png_set_strip_16;
   lib.png_sig_cmp = png_sig_cmp;
 }
 ++lib.loaded;

 return 0;
}
void IMG_QuitPNG()
{
 if ( lib.loaded == 0 ) {
   return;
 }
 if ( lib.loaded == 1 ) {
 }
 --lib.loaded;
}
#endif /* LOAD_PNG_DYNAMIC */

/* See if an image is contained in a data source */
int IMG_isPNG(SDL_RWops *src)
{
 int start;
 int is_PNG;
 Uint8 magic[4];

 if ( !src )
   return 0;
 start = SDL_RWtell(src);
 is_PNG = 0;
 if ( SDL_RWread(src, magic, 1, sizeof(magic)) == sizeof(magic) ) {
                if ( magic[0] == 0x89 &&
                     magic[1] == 'P' &&
                     magic[2] == 'N' &&
                     magic[3] == 'G' ) {
     is_PNG = 1;
   }
 }
 SDL_RWseek(src, start, RW_SEEK_SET);
 return(is_PNG);
}

/* Load a PNG type image from an SDL datasource */
static void png_read_data(png_structp ctx, png_bytep area, png_size_t size)
{
 SDL_RWops *src;

 src = (SDL_RWops *)lib.png_get_io_ptr(ctx);
 SDL_RWread(src, area, size, 1);
}
SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
{
 int start;
 const char *error;
 SDL_Surface *volatile surface;
 png_structp png_ptr;
 png_infop info_ptr;
 png_uint_32 width, height;
 int bit_depth, color_type, interlace_type;
 Uint32 Rmask;
 Uint32 Gmask;
 Uint32 Bmask;
 Uint32 Amask;
 SDL_Palette *palette;
 png_bytep *volatile row_pointers;
 int row, i;
 volatile int ckey = -1;
 png_color_16 *transv;

 if ( !src ) {
   /* The error message has been set in SDL_RWFromFile */
   return NULL;
 }
 start = SDL_RWtell(src);

 if ( !IMG_Init(IMG_INIT_PNG) ) {
   return NULL;
 }

 /* Initialize the data we will clean up when we're done */
 error = NULL;
 png_ptr = NULL; info_ptr = NULL; row_pointers = NULL; surface = NULL;

 /* Create the PNG loading context structure */
 png_ptr = lib.png_create_read_struct(PNG_LIBPNG_VER_STRING,
           NULL,NULL,NULL);
 if (png_ptr == NULL){
   error = "Couldn't allocate memory for PNG file or incompatible PNG dll";
   goto done;
 }

  /* Allocate/initialize the memory for image information.  REQUIRED. */
 info_ptr = lib.png_create_info_struct(png_ptr);
 if (info_ptr == NULL) {
   error = "Couldn't create image information for PNG file";
   goto done;
 }

 /* Set error handling if you are using setjmp/longjmp method (this is
  * the normal method of doing things with libpng).  REQUIRED unless you
  * set up your own error handlers in png_create_read_struct() earlier.
  */
 if ( setjmp(png_ptr->jmpbuf) ) {
   error = "Error reading the PNG file.";
   goto done;
 }

 /* Set up the input control */
 lib.png_set_read_fn(png_ptr, src, png_read_data);

 /* Read PNG header info */
 lib.png_read_info(png_ptr, info_ptr);
 lib.png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth,
     &color_type, &interlace_type, NULL, NULL);

 /* tell libpng to strip 16 bit/color files down to 8 bits/color */
 lib.png_set_strip_16(png_ptr) ;

 /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
  * byte into separate bytes (useful for paletted and grayscale images).
  */
 lib.png_set_packing(png_ptr);

 /* scale greyscale values to the range 0..255 */
 if(color_type == PNG_COLOR_TYPE_GRAY)
   lib.png_set_expand(png_ptr);

 /* For images with a single "transparent colour", set colour key;
    if more than one index has transparency, or if partially transparent
    entries exist, use full alpha channel */
 if (lib.png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
         int num_trans;
   Uint8 *trans;
   lib.png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans,
          &transv);
   if(color_type == PNG_COLOR_TYPE_PALETTE) {
       /* Check if all tRNS entries are opaque except one */
       int i, t = -1;
       for(i = 0; i < num_trans; i++)
     if(trans[i] == 0) {
         if(t >= 0)
       break;
         t = i;
     } else if(trans[i] != 255)
         break;
       if(i == num_trans) {
     /* exactly one transparent index */
     ckey = t;
       } else {
     /* more than one transparent index, or translucency */
     lib.png_set_expand(png_ptr);
       }
   } else
       ckey = 0; /* actual value will be set later */
 }

 if ( color_type == PNG_COLOR_TYPE_GRAY_ALPHA )
   lib.png_set_gray_to_rgb(png_ptr);

 lib.png_read_update_info(png_ptr, info_ptr);

 lib.png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth,
     &color_type, &interlace_type, NULL, NULL);

 /* Allocate the SDL surface to hold the image */
 Rmask = Gmask = Bmask = Amask = 0 ;
 if ( color_type != PNG_COLOR_TYPE_PALETTE ) {
   if ( SDL_BYTEORDER == SDL_LIL_ENDIAN ) {
     Rmask = 0x000000FF;
     Gmask = 0x0000FF00;
     Bmask = 0x00FF0000;
     Amask = (info_ptr->channels == 4) ? 0xFF000000 : 0;
   } else {
           int s = (info_ptr->channels == 4) ? 0 : 8;
     Rmask = 0xFF000000 >> s;
     Gmask = 0x00FF0000 >> s;
     Bmask = 0x0000FF00 >> s;
     Amask = 0x000000FF >> s;
   }
 }
 surface = SDL_AllocSurface(SDL_SWSURFACE, width, height,
     bit_depth*info_ptr->channels, Rmask,Gmask,Bmask,Amask);
 if ( surface == NULL ) {
   error = "Out of memory";
   goto done;
 }

 if(ckey != -1) {
         if(color_type != PNG_COLOR_TYPE_PALETTE)
     /* FIXME: Should these be truncated or shifted down? */
           ckey = SDL_MapRGB(surface->format,
                      (Uint8)transv->red,
                      (Uint8)transv->green,
                      (Uint8)transv->blue);
         SDL_SetColorKey(surface, SDL_SRCCOLORKEY, ckey);
 }

 /* Create the array of pointers to image data */
 row_pointers = (png_bytep*) malloc(sizeof(png_bytep)*height);
 if ( (row_pointers == NULL) ) {
   error = "Out of memory";
   goto done;
 }
 for (row = 0; row < (int)height; row++) {
   row_pointers[row] = (png_bytep)
       (Uint8 *)surface->pixels + row*surface->pitch;
 }

 /* Read the entire image in one go */
 lib.png_read_image(png_ptr, row_pointers);

 /* and we're done!  (png_read_end() can be omitted if no processing of
  * post-IDAT text/time/etc. is desired)
  * In some cases it can't read PNG's created by some popular programs (ACDSEE),
  * we do not want to process comments, so we omit png_read_end

 lib.png_read_end(png_ptr, info_ptr);
 */

 /* Load the palette, if any */
 palette = surface->format->palette;
 if ( palette ) {
     if(color_type == PNG_COLOR_TYPE_GRAY) {
   palette->ncolors = 256;
   for(i = 0; i < 256; i++) {
       palette->colors[i].r = i;
       palette->colors[i].g = i;
       palette->colors[i].b = i;
   }
     } else if (info_ptr->num_palette > 0 ) {
   palette->ncolors = info_ptr->num_palette;
   for( i=0; i<info_ptr->num_palette; ++i ) {
       palette->colors[i].b = info_ptr->palette[i].blue;
       palette->colors[i].g = info_ptr->palette[i].green;
       palette->colors[i].r = info_ptr->palette[i].red;
   }
     }
 }

done:  /* Clean up and return */
 if ( png_ptr ) {
   lib.png_destroy_read_struct(&png_ptr,
                           info_ptr ? &info_ptr : (png_infopp)0,
               (png_infopp)0);
 }
 if ( row_pointers ) {
   free(row_pointers);
 }
 if ( error ) {
   SDL_RWseek(src, start, RW_SEEK_SET);
   if ( surface ) {
     SDL_FreeSurface(surface);
     surface = NULL;
   }
   IMG_SetError(error);
 }
 return(surface);
}

#else

int IMG_InitPNG()
{
 IMG_SetError("PNG images are not supported");
 return(-1);
}

void IMG_QuitPNG()
{
}

/* See if an image is contained in a data source */
int IMG_isPNG(SDL_RWops *src)
{
 return(0);
}

/* Load a PNG type image from an SDL datasource */
SDL_Surface *IMG_LoadPNG_RW(SDL_RWops *src)
{
 return(NULL);
}

#endif /* LOAD_PNG */

#endif /* !defined(__APPLE__) || defined(SDL_IMAGE_USE_COMMON_BACKEND) */