SDL2/test/testbitmap.c

/* Simple program:  Test bitmap blits */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "SDL.h"
#include "picture.xbm"

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void
quit(int rc)
{
    SDL_Quit();
    exit(rc);
}

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 < w; ++i, ++buf) {
                byte = *buf;
                *buf = 0;
                for (j = 7; j >= 0; --j) {
                    *buf |= (byte & 0x01) << j;
                    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, k, done;
    SDL_Event event;
    Uint16 *buffer16;
    Uint16 color;
    Uint8 gradient;
    SDL_Color palette[256];

    int video_w, video_h;

    /* Initialize SDL */
    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return (1);
    }

    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]);
            quit(1);
        }
    }

#ifdef __IPHONEOS__
    video_w = 320;
    video_h = 480;
#else
    video_w = 640;
    video_h = 480;
#endif

    /* Set 640x480 video mode */
    if ((screen =
         SDL_SetVideoMode(video_w, video_h, video_bpp, videoflags)) == NULL) {
        fprintf(stderr, "Couldn't set %%d%d video mode: %s\n", video_w,
                video_h, video_bpp, SDL_GetError());
        quit(2);
    }

    if (video_bpp == 8) {
        /* Set a gray colormap, reverse order from white to black */
        for (i = 0; i < 256; ++i) {
            palette[i].r = 255 - i;
            palette[i].g = 255 - i;
            palette[i].b = 255 - i;
        }
        SDL_SetColors(screen, palette, 0, 256);
    }

    /* Set the surface pixels and refresh! */
    if (SDL_LockSurface(screen) < 0) {
        fprintf(stderr, "Couldn't lock the display surface: %s\n",
                SDL_GetError());
        quit(2);
    }
    buffer = (Uint8 *) screen->pixels;
    if (screen->format->BytesPerPixel != 2) {
        for (i = 0; i < screen->h; ++i) {
            memset(buffer, (i * 255) / screen->h, screen->pitch);
            buffer += screen->pitch;
        }
    } else {
        for (i = 0; i < screen->h; ++i) {
            gradient = ((i * 255) / screen->h);
            color = SDL_MapRGB(screen->format, gradient, gradient, gradient);
            buffer16 = (Uint16 *) buffer;
            for (k = 0; k < screen->w; k++) {
                *(buffer16 + k) = color;
            }
            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) {
        quit(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);
    SDL_Quit();
    return (0);
}