程式語言 - X Window (X11) - C/C++ - Create Image

參考資訊：
https://github.com/QMonkey/Xlib-demo
https://people.scs.carleton.ca/~claurend/Courses/COMP2401/Notes/COMP2401_Ch8_Graphics.pdf

main.c

#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <stdlib.h>
#include <X11/Xlib.h>
   
int main(int argc, char *argv[])
{
    const int w = 320;
    const int h = 240;

    GC gc = 0;
    Window win = 0;
    Display *display = NULL;
  
    display = XOpenDisplay(NULL);
    win = XCreateSimpleWindow(
        display,
        RootWindow(display, 0),
        0,
        0,
        w,
        h,
        0,
        0,
        0xffffff);
   
    XStoreName(display, win, "main");
    gc = XCreateGC(display, win, 0, NULL);
    XMapWindow(display, win);
    XFlush(display);
    usleep(100000);

    XImage *ximage = NULL;
    Visual *visual = DefaultVisual(display, 0);

    int i = 0;
    int j = 0;
    void *pixels = malloc(w * h * 4);
    uint32_t *p = (uint32_t *)pixels;

    for (i = 0; i < w; i++) {
        for (j = 0; j < h; j++) {
            *p++ = 0xffff0000;
        }
    }

    ximage = XCreateImage(display, visual, 24, ZPixmap, 0, pixels, w, h, 32, 0);
    XPutImage(display, win, gc, ximage, 0, 0, 0, 0, w, h);
    XFlush(display);
    usleep(3000000);
    free(pixels);

    XUnmapWindow(display, win);
    XDestroyWindow(display, win);
    XCloseDisplay(display);
   
    return 0;
}

編譯、測試

$ gcc main.c -o main -lX11
$ ./main