src/video/SDL_bmp.c
author Cameron Cawley
Wed, 24 Apr 2019 20:28:21 +0100
branchSDL-1.2
changeset 12722 33940ce0a0ba
parent 12646 4646533663ae
child 12831 f1f5878be5db
permissions -rw-r--r--
Remove duplicate case value
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/*
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    SDL - Simple DirectMedia Layer
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    Copyright (C) 1997-2012 Sam Lantinga
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    This library is free software; you can redistribute it and/or
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    modify it under the terms of the GNU Lesser General Public
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    License as published by the Free Software Foundation; either
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    version 2.1 of the License, or (at your option) any later version.
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    This library is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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    Lesser General Public License for more details.
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    You should have received a copy of the GNU Lesser General Public
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    License along with this library; if not, write to the Free Software
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    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
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    Sam Lantinga
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    slouken@libsdl.org
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*/
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#include "SDL_config.h"
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/* 
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   Code to load and save surfaces in Windows BMP format.
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   Why support BMP format?  Well, it's a native format for Windows, and
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   most image processing programs can read and write it.  It would be nice
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   to be able to have at least one image format that we can natively load
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   and save, and since PNG is so complex that it would bloat the library,
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   BMP is a good alternative. 
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   This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp.
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*/
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#include "SDL_video.h"
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#include "SDL_endian.h"
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/* Compression encodings for BMP files */
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#ifndef BI_RGB
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#define BI_RGB		0
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#define BI_RLE8		1
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#define BI_RLE4		2
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#define BI_BITFIELDS	3
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#endif
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SDL_Surface * SDL_LoadBMP_RW (SDL_RWops *src, int freesrc)
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{
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	SDL_bool was_error;
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	long fp_offset = 0;
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	int bmpPitch;
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	int i, pad;
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	SDL_Surface *surface;
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	Uint32 Rmask;
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	Uint32 Gmask;
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	Uint32 Bmask;
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	SDL_Palette *palette;
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	Uint8 *bits;
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	Uint8 *top, *end;
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	SDL_bool topDown;
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	int ExpandBMP;
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	/* The Win32 BMP file header (14 bytes) */
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	char   magic[2];
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	Uint32 bfSize;
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	Uint16 bfReserved1;
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	Uint16 bfReserved2;
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	Uint32 bfOffBits;
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	/* The Win32 BITMAPINFOHEADER struct (40 bytes) */
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	Uint32 biSize;
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	Sint32 biWidth;
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	Sint32 biHeight;
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	Uint16 biPlanes;
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	Uint16 biBitCount;
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	Uint32 biCompression;
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	Uint32 biSizeImage;
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	Sint32 biXPelsPerMeter;
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	Sint32 biYPelsPerMeter;
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	Uint32 biClrUsed;
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	Uint32 biClrImportant;
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	/* Make sure we are passed a valid data source */
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	surface = NULL;
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	was_error = SDL_FALSE;
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	if ( src == NULL ) {
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		was_error = SDL_TRUE;
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		goto done;
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	}
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	/* Read in the BMP file header */
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	fp_offset = SDL_RWtell(src);
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	SDL_ClearError();
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	if ( SDL_RWread(src, magic, 1, 2) != 2 ) {
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		SDL_Error(SDL_EFREAD);
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		was_error = SDL_TRUE;
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		goto done;
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	}
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	if ( SDL_strncmp(magic, "BM", 2) != 0 ) {
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		SDL_SetError("File is not a Windows BMP file");
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		was_error = SDL_TRUE;
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		goto done;
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	}
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	bfSize		= SDL_ReadLE32(src);
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	bfReserved1	= SDL_ReadLE16(src);
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	bfReserved2	= SDL_ReadLE16(src);
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	bfOffBits	= SDL_ReadLE32(src);
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	/* Read the Win32 BITMAPINFOHEADER */
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	biSize		= SDL_ReadLE32(src);
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	if ( biSize == 12 ) {
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		biWidth		= (Uint32)SDL_ReadLE16(src);
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		biHeight	= (Uint32)SDL_ReadLE16(src);
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		biPlanes	= SDL_ReadLE16(src);
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		biBitCount	= SDL_ReadLE16(src);
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		biCompression	= BI_RGB;
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		biSizeImage	= 0;
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		biXPelsPerMeter	= 0;
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		biYPelsPerMeter	= 0;
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		biClrUsed	= 0;
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		biClrImportant	= 0;
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	} else {
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		biWidth		= SDL_ReadLE32(src);
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		biHeight	= SDL_ReadLE32(src);
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		biPlanes	= SDL_ReadLE16(src);
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		biBitCount	= SDL_ReadLE16(src);
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		biCompression	= SDL_ReadLE32(src);
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		biSizeImage	= SDL_ReadLE32(src);
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		biXPelsPerMeter	= SDL_ReadLE32(src);
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		biYPelsPerMeter	= SDL_ReadLE32(src);
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		biClrUsed	= SDL_ReadLE32(src);
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		biClrImportant	= SDL_ReadLE32(src);
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	}
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	/* stop some compiler warnings. */
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	(void) bfSize;
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	(void) bfReserved1;
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	(void) bfReserved2;
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	(void) biPlanes;
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	(void) biSizeImage;
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	(void) biXPelsPerMeter;
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	(void) biYPelsPerMeter;
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	(void) biClrImportant;
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	if (biHeight < 0) {
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		topDown = SDL_TRUE;
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		biHeight = -biHeight;
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	} else {
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		topDown = SDL_FALSE;
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	}
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	/* Check for read error */
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	if ( SDL_strcmp(SDL_GetError(), "") != 0 ) {
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		was_error = SDL_TRUE;
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		goto done;
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	}
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	/* Expand 1 and 4 bit bitmaps to 8 bits per pixel */
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	switch (biBitCount) {
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		case 1:
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		case 4:
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			ExpandBMP = biBitCount;
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			biBitCount = 8;
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			break;
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		case 2:
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		case 3:
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		case 5:
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		case 6:
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		case 7:
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			SDL_SetError("%d-bpp BMP images are not supported", biBitCount);
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			was_error = SDL_TRUE;
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			goto done;
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		default:
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			ExpandBMP = 0;
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			break;
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	}
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	/* We don't support any BMP compression right now */
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	Rmask = Gmask = Bmask = 0;
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	switch (biCompression) {
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		case BI_RGB:
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			/* If there are no masks, use the defaults */
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			if ( bfOffBits == (14+biSize) ) {
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				/* Default values for the BMP format */
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				switch (biBitCount) {
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					case 15:
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					case 16:
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						Rmask = 0x7C00;
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						Gmask = 0x03E0;
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						Bmask = 0x001F;
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						break;
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					case 24:
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#if SDL_BYTEORDER == SDL_BIG_ENDIAN
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					        Rmask = 0x000000FF;
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					        Gmask = 0x0000FF00;
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					        Bmask = 0x00FF0000;
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						break;
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#endif
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					case 32:
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						Rmask = 0x00FF0000;
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						Gmask = 0x0000FF00;
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						Bmask = 0x000000FF;
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						break;
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					default:
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						break;
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				}
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				break;
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			}
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			/* Fall through -- read the RGB masks */
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		case BI_BITFIELDS:
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			switch (biBitCount) {
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				case 15:
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   215
				case 16:
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				case 32:
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					Rmask = SDL_ReadLE32(src);
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					Gmask = SDL_ReadLE32(src);
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					Bmask = SDL_ReadLE32(src);
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					break;
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				default:
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					break;
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			}
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			break;
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		default:
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			SDL_SetError("Compressed BMP files not supported");
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			was_error = SDL_TRUE;
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			goto done;
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	}
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	/* Create a compatible surface, note that the colors are RGB ordered */
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	surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
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			biWidth, biHeight, biBitCount, Rmask, Gmask, Bmask, 0);
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	if ( surface == NULL ) {
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		was_error = SDL_TRUE;
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		goto done;
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   237
	}
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   238
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   239
	/* Load the palette, if any */
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   240
	palette = (surface->format)->palette;
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   241
	if ( palette ) {
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   242
		if ( biClrUsed == 0 ) {
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   243
			biClrUsed = 1 << biBitCount;
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		} else if ( biClrUsed > (1 << biBitCount) ) {
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			SDL_SetError("BMP file has an invalid number of colors");
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			was_error = SDL_TRUE;
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			goto done;
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		}
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		if ( biSize == 12 ) {
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   250
			for ( i = 0; i < (int)biClrUsed; ++i ) {
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   251
				SDL_RWread(src, &palette->colors[i].b, 1, 1);
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				SDL_RWread(src, &palette->colors[i].g, 1, 1);
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				SDL_RWread(src, &palette->colors[i].r, 1, 1);
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				palette->colors[i].unused = 0;
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			}	
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   256
		} else {
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   257
			for ( i = 0; i < (int)biClrUsed; ++i ) {
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				SDL_RWread(src, &palette->colors[i].b, 1, 1);
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				SDL_RWread(src, &palette->colors[i].g, 1, 1);
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				SDL_RWread(src, &palette->colors[i].r, 1, 1);
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				SDL_RWread(src, &palette->colors[i].unused, 1, 1);
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			}	
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   263
		}
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   264
		palette->ncolors = biClrUsed;
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   265
	}
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   266
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   267
	/* Read the surface pixels.  Note that the bmp image is upside down */
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	if ( SDL_RWseek(src, fp_offset+bfOffBits, RW_SEEK_SET) < 0 ) {
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   269
		SDL_Error(SDL_EFSEEK);
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		was_error = SDL_TRUE;
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   271
		goto done;
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   272
	}
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   273
	top = (Uint8 *)surface->pixels;
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   274
	end = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
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   275
	switch (ExpandBMP) {
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   276
		case 1:
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   277
			bmpPitch = (biWidth + 7) >> 3;
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   278
			pad  = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
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   279
			break;
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   280
		case 4:
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   281
			bmpPitch = (biWidth + 1) >> 1;
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   282
			pad  = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
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   283
			break;
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   284
		default:
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   285
			pad  = ((surface->pitch%4) ?
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   286
					(4-(surface->pitch%4)) : 0);
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   287
			break;
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   288
	}
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   289
	if ( topDown ) {
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   290
		bits = top;
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   291
	} else {
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   292
		bits = end - surface->pitch;
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   293
	}
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   294
	while ( bits >= top && bits < end ) {
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   295
		switch (ExpandBMP) {
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   296
			case 1:
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   297
			case 4: {
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   298
			Uint8 pixel = 0;
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   299
			int   shift = (8-ExpandBMP);
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   300
			for ( i=0; i<surface->w; ++i ) {
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   301
				if ( i%(8/ExpandBMP) == 0 ) {
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   302
					if ( !SDL_RWread(src, &pixel, 1, 1) ) {
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   303
						SDL_SetError(
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   304
					"Error reading from BMP");
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   305
						was_error = SDL_TRUE;
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   306
						goto done;
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   307
					}
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   308
				}
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   309
				*(bits+i) = (pixel>>shift);
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   310
				pixel <<= ExpandBMP;
slouken@0
   311
			} }
slouken@0
   312
			break;
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   313
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   314
			default:
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   315
			if ( SDL_RWread(src, bits, 1, surface->pitch)
slouken@0
   316
							 != surface->pitch ) {
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   317
				SDL_Error(SDL_EFREAD);
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   318
				was_error = SDL_TRUE;
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   319
				goto done;
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   320
			}
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   321
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
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   322
			/* Byte-swap the pixels if needed. Note that the 24bpp
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   323
			   case has already been taken care of above. */
slouken@0
   324
			switch(biBitCount) {
slouken@0
   325
				case 15:
slouken@0
   326
				case 16: {
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   327
				        Uint16 *pix = (Uint16 *)bits;
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   328
					for(i = 0; i < surface->w; i++)
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   329
					        pix[i] = SDL_Swap16(pix[i]);
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   330
					break;
slouken@0
   331
				}
slouken@0
   332
slouken@0
   333
				case 32: {
slouken@0
   334
				        Uint32 *pix = (Uint32 *)bits;
slouken@0
   335
					for(i = 0; i < surface->w; i++)
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   336
					        pix[i] = SDL_Swap32(pix[i]);
slouken@0
   337
					break;
slouken@0
   338
				}
slouken@0
   339
			}
slouken@0
   340
#endif
slouken@0
   341
			break;
slouken@0
   342
		}
slouken@0
   343
		/* Skip padding bytes, ugh */
slouken@0
   344
		if ( pad ) {
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   345
			Uint8 padbyte;
slouken@0
   346
			for ( i=0; i<pad; ++i ) {
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   347
				SDL_RWread(src, &padbyte, 1, 1);
slouken@0
   348
			}
slouken@0
   349
		}
slouken@4241
   350
		if ( topDown ) {
slouken@4241
   351
			bits += surface->pitch;
slouken@4241
   352
		} else {
slouken@4241
   353
			bits -= surface->pitch;
slouken@4241
   354
		}
slouken@0
   355
	}
slouken@0
   356
done:
slouken@0
   357
	if ( was_error ) {
slouken@1329
   358
		if ( src ) {
slouken@1330
   359
			SDL_RWseek(src, fp_offset, RW_SEEK_SET);
slouken@1329
   360
		}
slouken@0
   361
		if ( surface ) {
slouken@0
   362
			SDL_FreeSurface(surface);
slouken@0
   363
		}
slouken@0
   364
		surface = NULL;
slouken@0
   365
	}
slouken@0
   366
	if ( freesrc && src ) {
slouken@0
   367
		SDL_RWclose(src);
slouken@0
   368
	}
slouken@0
   369
	return(surface);
slouken@0
   370
}
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int SDL_SaveBMP_RW (SDL_Surface *saveme, SDL_RWops *dst, int freedst)
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{
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	long fp_offset;
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	int i, pad;
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	SDL_Surface *surface;
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	Uint8 *bits;
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	/* The Win32 BMP file header (14 bytes) */
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	char   magic[2] = { 'B', 'M' };
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	Uint32 bfSize;
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	Uint16 bfReserved1;
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	Uint16 bfReserved2;
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	Uint32 bfOffBits;
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	/* The Win32 BITMAPINFOHEADER struct (40 bytes) */
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	Uint32 biSize;
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	Sint32 biWidth;
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	Sint32 biHeight;
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	Uint16 biPlanes;
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	Uint16 biBitCount;
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	Uint32 biCompression;
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	Uint32 biSizeImage;
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	Sint32 biXPelsPerMeter;
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	Sint32 biYPelsPerMeter;
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	Uint32 biClrUsed;
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	Uint32 biClrImportant;
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	/* Make sure we have somewhere to save */
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	surface = NULL;
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	if ( dst ) {
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		if ( saveme->format->palette ) {
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			if ( saveme->format->BitsPerPixel == 8 ) {
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				surface = saveme;
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			} else {
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				SDL_SetError("%d bpp BMP files not supported",
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						saveme->format->BitsPerPixel);
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			}
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		}
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		else if ( (saveme->format->BitsPerPixel == 24) &&
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN
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				(saveme->format->Rmask == 0x00FF0000) &&
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				(saveme->format->Gmask == 0x0000FF00) &&
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				(saveme->format->Bmask == 0x000000FF)
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#else
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				(saveme->format->Rmask == 0x000000FF) &&
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				(saveme->format->Gmask == 0x0000FF00) &&
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				(saveme->format->Bmask == 0x00FF0000)
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#endif
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			  ) {
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			surface = saveme;
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		} else {
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			SDL_Rect bounds;
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			/* Convert to 24 bits per pixel */
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			surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
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					saveme->w, saveme->h, 24,
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#if SDL_BYTEORDER == SDL_LIL_ENDIAN
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					0x00FF0000, 0x0000FF00, 0x000000FF,
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#else
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					0x000000FF, 0x0000FF00, 0x00FF0000,
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#endif
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					0);
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			if ( surface != NULL ) {
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				bounds.x = 0;
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				bounds.y = 0;
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				bounds.w = saveme->w;
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				bounds.h = saveme->h;
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				if ( SDL_LowerBlit(saveme, &bounds, surface,
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							&bounds) < 0 ) {
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					SDL_FreeSurface(surface);
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					SDL_SetError(
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					"Couldn't convert image to 24 bpp");
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					surface = NULL;
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				}
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			}
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		}
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	}
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	if ( surface && (SDL_LockSurface(surface) == 0) ) {
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		const int bw = surface->w*surface->format->BytesPerPixel;
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		/* Set the BMP file header values */
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		bfSize = 0;		 /* We'll write this when we're done */
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		bfReserved1 = 0;
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		bfReserved2 = 0;
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		bfOffBits = 0;		/* We'll write this when we're done */
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		/* Write the BMP file header values */
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		fp_offset = SDL_RWtell(dst);
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		SDL_ClearError();
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		SDL_RWwrite(dst, magic, 2, 1);
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		SDL_WriteLE32(dst, bfSize);
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		SDL_WriteLE16(dst, bfReserved1);
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		SDL_WriteLE16(dst, bfReserved2);
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		SDL_WriteLE32(dst, bfOffBits);
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		/* Set the BMP info values */
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		biSize = 40;
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		biWidth = surface->w;
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		biHeight = surface->h;
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		biPlanes = 1;
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		biBitCount = surface->format->BitsPerPixel;
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		biCompression = BI_RGB;
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		biSizeImage = surface->h*surface->pitch;
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		biXPelsPerMeter = 0;
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   477
		biYPelsPerMeter = 0;
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   478
		if ( surface->format->palette ) {
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			biClrUsed = surface->format->palette->ncolors;
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   480
		} else {
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   481
			biClrUsed = 0;
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   482
		}
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		biClrImportant = 0;
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		/* Write the BMP info values */
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		SDL_WriteLE32(dst, biSize);
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		SDL_WriteLE32(dst, biWidth);
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		SDL_WriteLE32(dst, biHeight);
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		SDL_WriteLE16(dst, biPlanes);
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		SDL_WriteLE16(dst, biBitCount);
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		SDL_WriteLE32(dst, biCompression);
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		SDL_WriteLE32(dst, biSizeImage);
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		SDL_WriteLE32(dst, biXPelsPerMeter);
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		SDL_WriteLE32(dst, biYPelsPerMeter);
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		SDL_WriteLE32(dst, biClrUsed);
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		SDL_WriteLE32(dst, biClrImportant);
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		/* Write the palette (in BGR color order) */
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		if ( surface->format->palette ) {
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			SDL_Color *colors;
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			int       ncolors;
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   502
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   503
			colors = surface->format->palette->colors;
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   504
			ncolors = surface->format->palette->ncolors;
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			for ( i=0; i<ncolors; ++i ) {
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				SDL_RWwrite(dst, &colors[i].b, 1, 1);
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				SDL_RWwrite(dst, &colors[i].g, 1, 1);
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   508
				SDL_RWwrite(dst, &colors[i].r, 1, 1);
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				SDL_RWwrite(dst, &colors[i].unused, 1, 1);
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   510
			}
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   511
		}
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   513
		/* Write the bitmap offset */
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   514
		bfOffBits = SDL_RWtell(dst)-fp_offset;
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		if ( SDL_RWseek(dst, fp_offset+10, RW_SEEK_SET) < 0 ) {
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   516
			SDL_Error(SDL_EFSEEK);
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   517
		}
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   518
		SDL_WriteLE32(dst, bfOffBits);
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		if ( SDL_RWseek(dst, fp_offset+bfOffBits, RW_SEEK_SET) < 0 ) {
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   520
			SDL_Error(SDL_EFSEEK);
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   521
		}
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   522
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   523
		/* Write the bitmap image upside down */
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   524
		bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
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   525
		pad  = ((bw%4) ? (4-(bw%4)) : 0);
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   526
		while ( bits > (Uint8 *)surface->pixels ) {
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   527
			bits -= surface->pitch;
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   528
			if ( SDL_RWwrite(dst, bits, 1, bw) != bw) {
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   529
				SDL_Error(SDL_EFWRITE);
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   530
				break;
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   531
			}
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   532
			if ( pad ) {
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   533
				const Uint8 padbyte = 0;
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   534
				for ( i=0; i<pad; ++i ) {
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   535
					SDL_RWwrite(dst, &padbyte, 1, 1);
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   536
				}
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   537
			}
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   538
		}
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   539
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   540
		/* Write the BMP file size */
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   541
		bfSize = SDL_RWtell(dst)-fp_offset;
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   542
		if ( SDL_RWseek(dst, fp_offset+2, RW_SEEK_SET) < 0 ) {
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   543
			SDL_Error(SDL_EFSEEK);
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   544
		}
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   545
		SDL_WriteLE32(dst, bfSize);
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   546
		if ( SDL_RWseek(dst, fp_offset+bfSize, RW_SEEK_SET) < 0 ) {
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   547
			SDL_Error(SDL_EFSEEK);
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   548
		}
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   549
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   550
		/* Close it up.. */
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   551
		SDL_UnlockSurface(surface);
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   552
		if ( surface != saveme ) {
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   553
			SDL_FreeSurface(surface);
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   554
		}
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   555
	}
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   556
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   557
	if ( freedst && dst ) {
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   558
		SDL_RWclose(dst);
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   559
	}
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   560
	return((SDL_strcmp(SDL_GetError(), "") == 0) ? 0 : -1);
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   561
}