diff src/video/SDL_bmp.c @ 0:74212992fb08

Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children e8157fcb3114
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/SDL_bmp.c	Thu Apr 26 16:45:43 2001 +0000
@@ -0,0 +1,527 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    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
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@devolution.com
+*/
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+#ifndef DISABLE_FILE
+
+/* 
+   Code to load and save surfaces in Windows BMP format.
+
+   Why support BMP format?  Well, it's a native format for Windows, and
+   most image processing programs can read and write it.  It would be nice
+   to be able to have at least one image format that we can natively load
+   and save, and since PNG is so complex that it would bloat the library,
+   BMP is a good alternative. 
+
+   This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp.
+*/
+
+#include <string.h>
+
+#include "SDL_error.h"
+#include "SDL_video.h"
+#include "SDL_endian.h"
+
+/* Compression encodings for BMP files */
+#ifndef BI_RGB
+#define BI_RGB		0
+#define BI_RLE8		1
+#define BI_RLE4		2
+#define BI_BITFIELDS	3
+#endif
+
+
+SDL_Surface * SDL_LoadBMP_RW (SDL_RWops *src, int freesrc)
+{
+	int was_error;
+	long fp_offset;
+	int bmpPitch;
+	int i, pad;
+	SDL_Surface *surface;
+	Uint32 Rmask;
+	Uint32 Gmask;
+	Uint32 Bmask;
+	SDL_Palette *palette;
+	Uint8 *bits;
+	int ExpandBMP;
+
+	/* The Win32 BMP file header (14 bytes) */
+	char   magic[2];
+	Uint32 bfSize;
+	Uint16 bfReserved1;
+	Uint16 bfReserved2;
+	Uint32 bfOffBits;
+
+	/* The Win32 BITMAPINFOHEADER struct (40 bytes) */
+	Uint32 biSize;
+	Sint32 biWidth;
+	Sint32 biHeight;
+	Uint16 biPlanes;
+	Uint16 biBitCount;
+	Uint32 biCompression;
+	Uint32 biSizeImage;
+	Sint32 biXPelsPerMeter;
+	Sint32 biYPelsPerMeter;
+	Uint32 biClrUsed;
+	Uint32 biClrImportant;
+
+	/* Make sure we are passed a valid data source */
+	surface = NULL;
+	was_error = 0;
+	if ( src == NULL ) {
+		was_error = 1;
+		goto done;
+	}
+
+	/* Read in the BMP file header */
+	fp_offset = SDL_RWtell(src);
+	SDL_ClearError();
+	if ( SDL_RWread(src, magic, 1, 2) != 2 ) {
+		SDL_Error(SDL_EFREAD);
+		was_error = 1;
+		goto done;
+	}
+	if ( strncmp(magic, "BM", 2) != 0 ) {
+		SDL_SetError("File is not a Windows BMP file");
+		was_error = 1;
+		goto done;
+	}
+	bfSize		= SDL_ReadLE32(src);
+	bfReserved1	= SDL_ReadLE16(src);
+	bfReserved2	= SDL_ReadLE16(src);
+	bfOffBits	= SDL_ReadLE32(src);
+
+	/* Read the Win32 BITMAPINFOHEADER */
+	biSize		= SDL_ReadLE32(src);
+	if ( biSize == 12 ) {
+		biWidth		= (Uint32)SDL_ReadLE16(src);
+		biHeight	= (Uint32)SDL_ReadLE16(src);
+		biPlanes	= SDL_ReadLE16(src);
+		biBitCount	= SDL_ReadLE16(src);
+		biCompression	= BI_RGB;
+		biSizeImage	= 0;
+		biXPelsPerMeter	= 0;
+		biYPelsPerMeter	= 0;
+		biClrUsed	= 0;
+		biClrImportant	= 0;
+	} else {
+		biWidth		= SDL_ReadLE32(src);
+		biHeight	= SDL_ReadLE32(src);
+		biPlanes	= SDL_ReadLE16(src);
+		biBitCount	= SDL_ReadLE16(src);
+		biCompression	= SDL_ReadLE32(src);
+		biSizeImage	= SDL_ReadLE32(src);
+		biXPelsPerMeter	= SDL_ReadLE32(src);
+		biYPelsPerMeter	= SDL_ReadLE32(src);
+		biClrUsed	= SDL_ReadLE32(src);
+		biClrImportant	= SDL_ReadLE32(src);
+	}
+
+	/* Check for read error */
+	if ( strcmp(SDL_GetError(), "") != 0 ) {
+		was_error = 1;
+		goto done;
+	}
+
+	/* Expand 1 and 4 bit bitmaps to 8 bits per pixel */
+	switch (biBitCount) {
+		case 1:
+		case 4:
+			ExpandBMP = biBitCount;
+			biBitCount = 8;
+			break;
+		default:
+			ExpandBMP = 0;
+			break;
+	}
+
+	/* We don't support any BMP compression right now */
+	Rmask = Gmask = Bmask = 0;
+	switch (biCompression) {
+		case BI_RGB:
+			/* If there are no masks, use the defaults */
+			if ( bfOffBits == (14+biSize) ) {
+				/* Default values for the BMP format */
+				switch (biBitCount) {
+					case 15:
+					case 16:
+						Rmask = 0x7C00;
+						Gmask = 0x03E0;
+						Bmask = 0x001F;
+						break;
+					case 24:
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+					        Rmask = 0x000000FF;
+					        Gmask = 0x0000FF00;
+					        Bmask = 0x00FF0000;
+						break;
+#endif
+					case 32:
+						Rmask = 0x00FF0000;
+						Gmask = 0x0000FF00;
+						Bmask = 0x000000FF;
+						break;
+					default:
+						break;
+				}
+				break;
+			}
+			/* Fall through -- read the RGB masks */
+
+		case BI_BITFIELDS:
+			switch (biBitCount) {
+				case 15:
+				case 16:
+				case 32:
+					Rmask = SDL_ReadLE32(src);
+					Gmask = SDL_ReadLE32(src);
+					Bmask = SDL_ReadLE32(src);
+					break;
+				default:
+					break;
+			}
+			break;
+		default:
+			SDL_SetError("Compressed BMP files not supported");
+			was_error = 1;
+			goto done;
+	}
+
+	/* Create a compatible surface, note that the colors are RGB ordered */
+	surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
+			biWidth, biHeight, biBitCount, Rmask, Gmask, Bmask, 0);
+	if ( surface == NULL ) {
+		was_error = 1;
+		goto done;
+	}
+
+	/* Load the palette, if any */
+	palette = (surface->format)->palette;
+	if ( palette ) {
+		if ( biClrUsed == 0 ) {
+			biClrUsed = 1 << biBitCount;
+		}
+		if ( biSize == 12 ) {
+			for ( i = 0; i < (int)biClrUsed; ++i ) {
+				SDL_RWread(src, &palette->colors[i].b, 1, 1);
+				SDL_RWread(src, &palette->colors[i].g, 1, 1);
+				SDL_RWread(src, &palette->colors[i].r, 1, 1);
+				palette->colors[i].unused = 0;
+			}	
+		} else {
+			for ( i = 0; i < (int)biClrUsed; ++i ) {
+				SDL_RWread(src, &palette->colors[i].b, 1, 1);
+				SDL_RWread(src, &palette->colors[i].g, 1, 1);
+				SDL_RWread(src, &palette->colors[i].r, 1, 1);
+				SDL_RWread(src, &palette->colors[i].unused, 1, 1);
+			}	
+		}
+		palette->ncolors = biClrUsed;
+	}
+
+	/* Read the surface pixels.  Note that the bmp image is upside down */
+	if ( SDL_RWseek(src, fp_offset+bfOffBits, SEEK_SET) < 0 ) {
+		SDL_Error(SDL_EFSEEK);
+		was_error = 1;
+		goto done;
+	}
+	bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
+	switch (ExpandBMP) {
+		case 1:
+			bmpPitch = (biWidth + 7) >> 3;
+			pad  = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
+			break;
+		case 4:
+			bmpPitch = (biWidth + 1) >> 1;
+			pad  = (((bmpPitch)%4) ? (4-((bmpPitch)%4)) : 0);
+			break;
+		default:
+			pad  = ((surface->pitch%4) ?
+					(4-(surface->pitch%4)) : 0);
+			break;
+	}
+	while ( bits > (Uint8 *)surface->pixels ) {
+		bits -= surface->pitch;
+		switch (ExpandBMP) {
+			case 1:
+			case 4: {
+			Uint8 pixel = 0;
+			int   shift = (8-ExpandBMP);
+			for ( i=0; i<surface->w; ++i ) {
+				if ( i%(8/ExpandBMP) == 0 ) {
+					if ( !SDL_RWread(src, &pixel, 1, 1) ) {
+						SDL_SetError(
+					"Error reading from BMP");
+						was_error = 1;
+						goto done;
+					}
+				}
+				*(bits+i) = (pixel>>shift);
+				pixel <<= ExpandBMP;
+			} }
+			break;
+
+			default:
+			if ( SDL_RWread(src, bits, 1, surface->pitch)
+							 != surface->pitch ) {
+				SDL_Error(SDL_EFREAD);
+				was_error = 1;
+				goto done;
+			}
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+			/* Byte-swap the pixels if needed. Note that the 24bpp
+			   case has already been taken care of above. */
+			switch(biBitCount) {
+				case 15:
+				case 16: {
+				        Uint16 *pix = (Uint16 *)bits;
+					for(i = 0; i < surface->w; i++)
+					        pix[i] = SDL_Swap16(pix[i]);
+					break;
+				}
+
+				case 32: {
+				        Uint32 *pix = (Uint32 *)bits;
+					for(i = 0; i < surface->w; i++)
+					        pix[i] = SDL_Swap32(pix[i]);
+					break;
+				}
+			}
+#endif
+			break;
+		}
+		/* Skip padding bytes, ugh */
+		if ( pad ) {
+			Uint8 padbyte;
+			for ( i=0; i<pad; ++i ) {
+				SDL_RWread(src, &padbyte, 1, 1);
+			}
+		}
+	}
+done:
+	if ( was_error ) {
+		if ( surface ) {
+			SDL_FreeSurface(surface);
+		}
+		surface = NULL;
+	}
+	if ( freesrc && src ) {
+		SDL_RWclose(src);
+	}
+	return(surface);
+}
+
+int SDL_SaveBMP_RW (SDL_Surface *saveme, SDL_RWops *dst, int freedst)
+{
+	long fp_offset;
+	int i, pad;
+	SDL_Surface *surface;
+	Uint8 *bits;
+
+	/* The Win32 BMP file header (14 bytes) */
+	char   magic[2] = { 'B', 'M' };
+	Uint32 bfSize;
+	Uint16 bfReserved1;
+	Uint16 bfReserved2;
+	Uint32 bfOffBits;
+
+	/* The Win32 BITMAPINFOHEADER struct (40 bytes) */
+	Uint32 biSize;
+	Sint32 biWidth;
+	Sint32 biHeight;
+	Uint16 biPlanes;
+	Uint16 biBitCount;
+	Uint32 biCompression;
+	Uint32 biSizeImage;
+	Sint32 biXPelsPerMeter;
+	Sint32 biYPelsPerMeter;
+	Uint32 biClrUsed;
+	Uint32 biClrImportant;
+
+	/* Make sure we have somewhere to save */
+	surface = NULL;
+	if ( dst ) {
+		if ( saveme->format->palette ) {
+			if ( saveme->format->BitsPerPixel == 8 ) {
+				surface = saveme;
+			} else {
+				SDL_SetError("%d bpp BMP files not supported",
+						saveme->format->BitsPerPixel);
+			}
+		}
+		else if ( (saveme->format->BitsPerPixel == 24) &&
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
+				(saveme->format->Rmask == 0x00FF0000) &&
+				(saveme->format->Gmask == 0x0000FF00) &&
+				(saveme->format->Bmask == 0x000000FF)
+#else
+				(saveme->format->Rmask == 0x000000FF) &&
+				(saveme->format->Gmask == 0x0000FF00) &&
+				(saveme->format->Bmask == 0x00FF0000)
+#endif
+			  ) {
+			surface = saveme;
+		} else {
+			SDL_Rect bounds;
+
+			/* Convert to 24 bits per pixel */
+			surface = SDL_CreateRGBSurface(SDL_SWSURFACE,
+					saveme->w, saveme->h, 24,
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
+					0x00FF0000, 0x0000FF00, 0x000000FF,
+#else
+					0x000000FF, 0x0000FF00, 0x00FF0000,
+#endif
+					0);
+			if ( surface != NULL ) {
+				bounds.x = 0;
+				bounds.y = 0;
+				bounds.w = saveme->w;
+				bounds.h = saveme->h;
+				if ( SDL_LowerBlit(saveme, &bounds, surface,
+							&bounds) < 0 ) {
+					SDL_FreeSurface(surface);
+					SDL_SetError(
+					"Couldn't convert image to 24 bpp");
+					surface = NULL;
+				}
+			}
+		}
+	}
+
+	if ( surface && (SDL_LockSurface(surface) == 0) ) {
+		/* Set the BMP file header values */
+		bfSize = 0;		 /* We'll write this when we're done */
+		bfReserved1 = 0;
+		bfReserved2 = 0;
+		bfOffBits = 0;		/* We'll write this when we're done */
+
+		/* Write the BMP file header values */
+		fp_offset = SDL_RWtell(dst);
+		SDL_ClearError();
+		SDL_RWwrite(dst, magic, 2, 1);
+		SDL_WriteLE32(dst, bfSize);
+		SDL_WriteLE16(dst, bfReserved1);
+		SDL_WriteLE16(dst, bfReserved2);
+		SDL_WriteLE32(dst, bfOffBits);
+
+		/* Set the BMP info values */
+		biSize = 40;
+		biWidth = surface->w;
+		biHeight = surface->h;
+		biPlanes = 1;
+		biBitCount = surface->format->BitsPerPixel;
+		biCompression = BI_RGB;
+		biSizeImage = surface->h*surface->pitch;
+		biXPelsPerMeter = 0;
+		biYPelsPerMeter = 0;
+		if ( surface->format->palette ) {
+			biClrUsed = surface->format->palette->ncolors;
+		} else {
+			biClrUsed = 0;
+		}
+		biClrImportant = 0;
+
+		/* Write the BMP info values */
+		SDL_WriteLE32(dst, biSize);
+		SDL_WriteLE32(dst, biWidth);
+		SDL_WriteLE32(dst, biHeight);
+		SDL_WriteLE16(dst, biPlanes);
+		SDL_WriteLE16(dst, biBitCount);
+		SDL_WriteLE32(dst, biCompression);
+		SDL_WriteLE32(dst, biSizeImage);
+		SDL_WriteLE32(dst, biXPelsPerMeter);
+		SDL_WriteLE32(dst, biYPelsPerMeter);
+		SDL_WriteLE32(dst, biClrUsed);
+		SDL_WriteLE32(dst, biClrImportant);
+
+		/* Write the palette (in BGR color order) */
+		if ( surface->format->palette ) {
+			SDL_Color *colors;
+			int       ncolors;
+
+			colors = surface->format->palette->colors;
+			ncolors = surface->format->palette->ncolors;
+			for ( i=0; i<ncolors; ++i ) {
+				SDL_RWwrite(dst, &colors[i].b, 1, 1);
+				SDL_RWwrite(dst, &colors[i].g, 1, 1);
+				SDL_RWwrite(dst, &colors[i].r, 1, 1);
+				SDL_RWwrite(dst, &colors[i].unused, 1, 1);
+			}
+		}
+
+		/* Write the bitmap offset */
+		bfOffBits = SDL_RWtell(dst)-fp_offset;
+		if ( SDL_RWseek(dst, fp_offset+10, SEEK_SET) < 0 ) {
+			SDL_Error(SDL_EFSEEK);
+		}
+		SDL_WriteLE32(dst, bfOffBits);
+		if ( SDL_RWseek(dst, fp_offset+bfOffBits, SEEK_SET) < 0 ) {
+			SDL_Error(SDL_EFSEEK);
+		}
+
+		/* Write the bitmap image upside down */
+		bits = (Uint8 *)surface->pixels+(surface->h*surface->pitch);
+		pad  = ((surface->pitch%4) ? (4-(surface->pitch%4)) : 0);
+		while ( bits > (Uint8 *)surface->pixels ) {
+			bits -= surface->pitch;
+			if ( SDL_RWwrite(dst, bits, 1, surface->pitch)
+							!= surface->pitch) {
+				SDL_Error(SDL_EFWRITE);
+				break;
+			}
+			if ( pad ) {
+				const Uint8 padbyte = 0;
+				for ( i=0; i<pad; ++i ) {
+					SDL_RWwrite(dst, &padbyte, 1, 1);
+				}
+			}
+		}
+
+		/* Write the BMP file size */
+		bfSize = SDL_RWtell(dst)-fp_offset;
+		if ( SDL_RWseek(dst, fp_offset+2, SEEK_SET) < 0 ) {
+			SDL_Error(SDL_EFSEEK);
+		}
+		SDL_WriteLE32(dst, bfSize);
+		if ( SDL_RWseek(dst, fp_offset+bfSize, SEEK_SET) < 0 ) {
+			SDL_Error(SDL_EFSEEK);
+		}
+
+		/* Close it up.. */
+		SDL_UnlockSurface(surface);
+		if ( surface != saveme ) {
+			SDL_FreeSurface(surface);
+		}
+	}
+
+	if ( freedst && dst ) {
+		SDL_RWclose(dst);
+	}
+	return((strcmp(SDL_GetError(), "") == 0) ? 0 : -1);
+}
+
+#endif /* ENABLE_FILE */