/*    SDL_image:  An example image loading library for use with SDL    Copyright (C) 1997-2006 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*//* 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_DYNAMICint 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;}#elseint 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;}