JPEG-MPEG編解碼技術書集的代碼

				
				/* Simple program:  Test bitmap blits */
				
				#include 
				#include 
				#include 
				
				#include "SDL.h"
				#include "picture.xbm"
				
				SDL_Surface *LoadXBM(SDL_Surface *screen, int w, int h, Uint8 *bits)
				{
					SDL_Surface *bitmap;
					Uint8 *line;
				
					/* Allocate the bitmap */
					bitmap = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 1, 0, 0, 0, 0);
					if ( bitmap == NULL ) {
						fprintf(stderr, "Couldn't allocate bitmap: %s\n",
										SDL_GetError());
						return(NULL);
					}
				
					/* Copy the pixels */
					line = (Uint8 *)bitmap->pixels;
					w = (w+7)/8;
					while ( h-- ) {
						memcpy(line, bits, w);
						/* X11 Bitmap images have the bits reversed */
						{ int i, j; Uint8 *buf, byte;
							for ( buf=line, i=0; i								byte = *buf;
								*buf = 0;
								for ( j=7; j>=0; --j ) {
									*buf |= (byte&0x01)									byte >>= 1;
								}
							}
						}
						line += bitmap->pitch;
						bits += w;
					}
					return(bitmap);
				}
				
				int main(int argc, char *argv[])
				{
					SDL_Surface *screen;
					SDL_Surface *bitmap;
					Uint8  video_bpp;
					Uint32 videoflags;
					Uint8 *buffer;
					int i, done;
					SDL_Event event;
				
					/* Initialize SDL */
					if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
						fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
						exit(1);
					}
					atexit(SDL_Quit);
				
					video_bpp = 0;
					videoflags = SDL_SWSURFACE;
					while ( argc > 1 ) {
						--argc;
						if ( strcmp(argv[argc-1], "-bpp") == 0 ) {
							video_bpp = atoi(argv[argc]);
							--argc;
						} else
						if ( strcmp(argv[argc], "-warp") == 0 ) {
							videoflags |= SDL_HWPALETTE;
						} else
						if ( strcmp(argv[argc], "-hw") == 0 ) {
							videoflags |= SDL_HWSURFACE;
						} else
						if ( strcmp(argv[argc], "-fullscreen") == 0 ) {
							videoflags |= SDL_FULLSCREEN;
						} else {
							fprintf(stderr,
							"Usage: %s [-bpp N] [-warp] [-hw] [-fullscreen]\n",
												argv[0]);
							exit(1);
						}
					}
				
					/* Set 640x480 video mode */
					if ( (screen=SDL_SetVideoMode(640,480,video_bpp,videoflags)) == NULL ) {
						fprintf(stderr, "Couldn't set 640x480x%d video mode: %s\n",
										video_bpp, SDL_GetError());
						exit(2);
					}
				
					/* Set the surface pixels and refresh! */
					if ( SDL_LockSurface(screen) < 0 ) {
						fprintf(stderr, "Couldn't lock the display surface: %s\n",
											SDL_GetError());
						exit(2);
					}
					buffer=(Uint8 *)screen->pixels;
					for ( i=0; ih; ++i ) {
						memset(buffer,(i*255)/screen->h, screen->pitch);
						buffer += screen->pitch;
					}
					SDL_UnlockSurface(screen);
					SDL_UpdateRect(screen, 0, 0, 0, 0);
				
					/* Load the bitmap */
					bitmap = LoadXBM(screen, picture_width, picture_height,
									(Uint8 *)picture_bits);
					if ( bitmap == NULL ) {
						exit(1);
					}
				
					/* Wait for a keystroke */
					done = 0;
					while ( !done ) {
						/* Check for events */
						while ( SDL_PollEvent(&event) ) {
							switch (event.type) {
								case SDL_MOUSEBUTTONDOWN: {
									SDL_Rect dst;
				
									dst.x = event.button.x - bitmap->w/2;
									dst.y = event.button.y - bitmap->h/2;
									dst.w = bitmap->w;
									dst.h = bitmap->h;
									SDL_BlitSurface(bitmap, NULL,
												screen, &dst);
									SDL_UpdateRects(screen,1,&dst);
									}
									break;
								case SDL_KEYDOWN:
									/* Any key press quits the app... */
									done = 1;
									break;
								case SDL_QUIT:
									done = 1;
									break;
								default:
									break;
							}
						}
					}
					SDL_FreeSurface(bitmap);
					return(0);
				}