example.c

   1 /* gifdec example -- simple GIF player using SDL2
   2  * compiling:
   3  *   cc `pkg-config --cflags --libs sdl2` -o example gifdec.c example.c
   4  * executing:
   5  *   ./example animation.gif
   6  * */
   7
   8 #include <stdio.h>
   9
  10 #include <SDL.h>
  11
  12 #include "gifdec.h"
  13
  14 int
  15 main(int argc, char *argv[])
  16 {
  17     SDL_Window *window;
  18     SDL_Renderer *renderer;
  19     SDL_Surface *surface;
  20     SDL_Texture *texture;
  21     SDL_Event event;
  22     gd_GIF *gif;
  23     char title[32] = {0};
  24     Uint8 *color, *frame;
  25     void *addr;
  26     int i, j;
  27     Uint32 pixel;
  28     int ret, paused, quit;
  29     Uint32 t0, t1, delay, delta;
  30
  31     if (argc != 2) {
  32         fprintf(stderr, "usage:\n  %s gif-file\n", argv[0]);
  33         return 1;
  34     }
  35     gif = gd_open_gif(argv[1]);
  36     if (!gif) {
  37         fprintf(stderr, "Could not open %s\n", argv[1]);
  38         return 1;
  39     }
  40     frame = malloc(gif->width * gif->height * 3);
  41     if (!frame) {
  42         fprintf(stderr, "Could not allocate frame\n");
  43         return 1;
  44     }
  45     if (SDL_Init(SDL_INIT_VIDEO|SDL_INIT_TIMER) != 0) {
  46         SDL_Log("Unable to initialize SDL: %s", SDL_GetError());
  47         return 1;
  48     }
  49     if (SDL_CreateWindowAndRenderer(gif->width, gif->height, SDL_WINDOW_RESIZABLE, &window, &renderer)) {
  50         SDL_Log("Couldn't create window and renderer: %s", SDL_GetError());
  51         return 1;
  52     }
  53     snprintf(title, sizeof(title) - 1, "GIF %dx%d %d colors",
  54              gif->width, gif->height, gif->palette->size);
  55     SDL_SetWindowTitle(window, title);
  56     color = &gif->gct.colors[gif->bgindex * 3];
  57     SDL_SetRenderDrawColor(renderer, color[0], color[1], color[2], 0x00);
  58     SDL_RenderClear(renderer);
  59     SDL_RenderPresent(renderer);
  60     surface = SDL_CreateRGBSurface(0, gif->width, gif->height, 32, 0, 0, 0, 0);
  61     if (!surface) {
  62         SDL_Log("SDL_CreateRGBSurface() failed: %s", SDL_GetError());
  63         return 1;
  64     }
  65     paused = 0;
  66     quit = 0;
  67     while (1) {
  68         while (SDL_PollEvent(&event) && !quit) {
  69             if (event.type == SDL_QUIT)
  70                 quit = 1;
  71             if (event.type == SDL_KEYDOWN) {
  72                 if (event.key.keysym.sym == SDLK_q)
  73                     quit = 1;
  74                 else if (event.key.keysym.sym == SDLK_SPACE)
  75                     paused = !paused;
  76             }
  77         }
  78         if (quit) break;
  79         if (paused) {
  80             SDL_Delay(10);
  81             continue;
  82         }
  83         t0 = SDL_GetTicks();
  84         ret = gd_get_frame(gif);
  85         if (ret == -1)
  86             break;
  87         SDL_LockSurface(surface);
  88         gd_render_frame(gif, frame);
  89         color = frame;
  90         for (i = 0; i < gif->height; i++) {
  91             for (j = 0; j < gif->width; j++) {
  92                 if (!gd_is_bgcolor(gif, color))
  93                     pixel = SDL_MapRGB(surface->format, color[0], color[1], color[2]);
  94                 else if (((i >> 2) + (j >> 2)) & 1)
  95                     pixel = SDL_MapRGB(surface->format, 0x7F, 0x7F, 0x7F);
  96                 else
  97                     pixel = SDL_MapRGB(surface->format, 0x00, 0x00, 0x00);
  98                 addr = surface->pixels + (i * surface->pitch + j * sizeof(pixel));
  99                 memcpy(addr, &pixel, sizeof(pixel));
 100                 color += 3;
 101             }
 102         }
 103         SDL_UnlockSurface(surface);
 104         texture = SDL_CreateTextureFromSurface(renderer, surface);
 105         SDL_RenderCopy(renderer, texture, NULL, NULL);
 106         SDL_RenderPresent(renderer);
 107         SDL_DestroyTexture(texture);
 108         t1 = SDL_GetTicks();
 109         delta = t1 - t0;
 110         delay = gif->gce.delay * 10;
 111         delay = delay > delta ? delay - delta : 1;
 112         SDL_Delay(delay);
 113         if (ret == 0)
 114             gd_rewind(gif);
 115     }
 116     SDL_FreeSurface(surface);
 117     SDL_DestroyRenderer(renderer);
 118     SDL_DestroyWindow(window);
 119     SDL_Quit();
 120     free(frame);
 121     gd_close_gif(gif);
 122     return 0;
 123 }