IMG.c
author Sam Lantinga <slouken@libsdl.org>
Sun, 04 Jan 2004 17:41:55 +0000
changeset 97 e1161bd417c4
parent 95 7fcb46931afc
child 110 23d7437faa1b
permissions -rw-r--r--
Updated copyright information for 2004 (Happy New Year!)
slouken@0
     1
/*
slouken@53
     2
    SDL_image:  An example image loading library for use with SDL
slouken@97
     3
    Copyright (C) 1999-2004 Sam Lantinga
slouken@0
     4
slouken@0
     5
    This library is free software; you can redistribute it and/or
slouken@0
     6
    modify it under the terms of the GNU Library General Public
slouken@0
     7
    License as published by the Free Software Foundation; either
slouken@0
     8
    version 2 of the License, or (at your option) any later version.
slouken@0
     9
slouken@0
    10
    This library is distributed in the hope that it will be useful,
slouken@0
    11
    but WITHOUT ANY WARRANTY; without even the implied warranty of
slouken@0
    12
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
slouken@0
    13
    Library General Public License for more details.
slouken@0
    14
slouken@0
    15
    You should have received a copy of the GNU Library General Public
slouken@0
    16
    License along with this library; if not, write to the Free
slouken@0
    17
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
slouken@0
    18
slouken@0
    19
    Sam Lantinga
slouken@53
    20
    slouken@libsdl.org
slouken@0
    21
*/
slouken@0
    22
slouken@53
    23
/* $Id$ */
slouken@53
    24
slouken@0
    25
/* A simple library to load images of various formats as SDL surfaces */
slouken@0
    26
slouken@0
    27
#include <stdio.h>
slouken@0
    28
#include <string.h>
slouken@0
    29
#include <ctype.h>
slouken@0
    30
slouken@0
    31
#include "SDL_image.h"
slouken@0
    32
slouken@7
    33
#define ARRAYSIZE(a) (sizeof(a) / sizeof((a)[0]))
slouken@7
    34
slouken@0
    35
/* Table of image detection and loading functions */
slouken@0
    36
static struct {
slouken@0
    37
	char *type;
slouken@0
    38
	int (*is)(SDL_RWops *src);
slouken@0
    39
	SDL_Surface *(*load)(SDL_RWops *src);
slouken@0
    40
} supported[] = {
slouken@24
    41
	/* keep magicless formats first */
slouken@95
    42
	{ "TGA", NULL,      IMG_LoadTGA_RW },
slouken@0
    43
	{ "BMP", IMG_isBMP, IMG_LoadBMP_RW },
slouken@24
    44
	{ "PNM", IMG_isPNM, IMG_LoadPNM_RW }, /* P[BGP]M share code */
slouken@7
    45
	{ "XPM", IMG_isXPM, IMG_LoadXPM_RW },
slouken@26
    46
	{ "XCF", IMG_isXCF, IMG_LoadXCF_RW },
slouken@0
    47
	{ "PCX", IMG_isPCX, IMG_LoadPCX_RW },
slouken@0
    48
	{ "GIF", IMG_isGIF, IMG_LoadGIF_RW },
slouken@0
    49
	{ "JPG", IMG_isJPG, IMG_LoadJPG_RW },
slouken@0
    50
	{ "TIF", IMG_isTIF, IMG_LoadTIF_RW },
slouken@45
    51
	{ "LBM", IMG_isLBM, IMG_LoadLBM_RW },
slouken@7
    52
	{ "PNG", IMG_isPNG, IMG_LoadPNG_RW }
slouken@0
    53
};
slouken@0
    54
slouken@89
    55
const SDL_version *IMG_Linked_Version(void)
slouken@89
    56
{
slouken@89
    57
	static SDL_version linked_version;
slouken@89
    58
	SDL_IMAGE_VERSION(&linked_version);
slouken@89
    59
	return(&linked_version);
slouken@89
    60
}
slouken@89
    61
slouken@0
    62
/* Load an image from a file */
slouken@0
    63
SDL_Surface *IMG_Load(const char *file)
slouken@0
    64
{
slouken@0
    65
    SDL_RWops *src = SDL_RWFromFile(file, "rb");
slouken@0
    66
    char *ext = strrchr(file, '.');
slouken@95
    67
    if(ext) {
slouken@95
    68
        ext++;
slouken@95
    69
    }
slouken@95
    70
    if(!src) {
slouken@95
    71
        /* The error message has been set in SDL_RWFromFile */
slouken@95
    72
        return NULL;
slouken@95
    73
    }
slouken@0
    74
    return IMG_LoadTyped_RW(src, 1, ext);
slouken@0
    75
}
slouken@0
    76
slouken@0
    77
/* Load an image from an SDL datasource (for compatibility) */
slouken@0
    78
SDL_Surface *IMG_Load_RW(SDL_RWops *src, int freesrc)
slouken@0
    79
{
slouken@0
    80
    return IMG_LoadTyped_RW(src, freesrc, NULL);
slouken@0
    81
}
slouken@0
    82
slouken@0
    83
/* Portable case-insensitive string compare function */
slouken@50
    84
static int IMG_string_equals(const char *str1, const char *str2)
slouken@0
    85
{
slouken@0
    86
	while ( *str1 && *str2 ) {
slouken@0
    87
		if ( toupper((unsigned char)*str1) !=
slouken@0
    88
		     toupper((unsigned char)*str2) )
slouken@0
    89
			break;
slouken@0
    90
		++str1;
slouken@0
    91
		++str2;
slouken@0
    92
	}
slouken@0
    93
	return (!*str1 && !*str2);
slouken@0
    94
}
slouken@0
    95
slouken@0
    96
/* Load an image from an SDL datasource, optionally specifying the type */
slouken@0
    97
SDL_Surface *IMG_LoadTyped_RW(SDL_RWops *src, int freesrc, char *type)
slouken@0
    98
{
slouken@0
    99
	int i, start;
slouken@0
   100
	SDL_Surface *image;
slouken@0
   101
slouken@0
   102
	/* Make sure there is something to do.. */
slouken@0
   103
	if ( src == NULL ) {
slouken@95
   104
		IMG_SetError("Passed a NULL data source");
slouken@0
   105
		return(NULL);
slouken@0
   106
	}
slouken@0
   107
slouken@0
   108
	/* See whether or not this data source can handle seeking */
slouken@0
   109
	if ( SDL_RWseek(src, 0, SEEK_CUR) < 0 ) {
slouken@0
   110
		IMG_SetError("Can't seek in this data source");
slouken@78
   111
		if(freesrc)
slouken@78
   112
			SDL_RWclose(src);
slouken@0
   113
		return(NULL);
slouken@0
   114
	}
slouken@0
   115
slouken@0
   116
	/* Detect the type of image being loaded */
slouken@0
   117
	start = SDL_RWtell(src);
slouken@0
   118
	image = NULL;
slouken@11
   119
	for ( i=0; i < ARRAYSIZE(supported); ++i ) {
slouken@62
   120
		if(supported[i].is) {
slouken@62
   121
			SDL_RWseek(src, start, SEEK_SET);
slouken@62
   122
			if(!supported[i].is(src))
slouken@62
   123
				continue;
slouken@62
   124
		} else {
slouken@62
   125
			/* magicless format */
slouken@62
   126
			if(!type
slouken@62
   127
			   || !IMG_string_equals(type, supported[i].type))
slouken@62
   128
				continue;
slouken@62
   129
		}
slouken@0
   130
#ifdef DEBUG_IMGLIB
slouken@62
   131
		fprintf(stderr, "IMGLIB: Loading image as %s\n",
slouken@62
   132
			supported[i].type);
slouken@0
   133
#endif
slouken@62
   134
		SDL_RWseek(src, start, SEEK_SET);
slouken@62
   135
		image = supported[i].load(src);
slouken@62
   136
		if(freesrc)
slouken@62
   137
			SDL_RWclose(src);
slouken@62
   138
		return image;
slouken@0
   139
	}
slouken@0
   140
slouken@0
   141
	if ( freesrc ) {
slouken@0
   142
		SDL_RWclose(src);
slouken@0
   143
	}
slouken@62
   144
	IMG_SetError("Unsupported image format");
slouken@62
   145
	return NULL;
slouken@0
   146
}
slouken@0
   147
slouken@0
   148
/* Invert the alpha of a surface for use with OpenGL
slouken@4
   149
   This function is a no-op and only kept for backwards compatibility.
slouken@0
   150
 */
slouken@0
   151
int IMG_InvertAlpha(int on)
slouken@0
   152
{
slouken@4
   153
    return 1;
slouken@0
   154
}