Added a bit more involved example of Zig and Xlib

Author Mitja Felicijan <mitja.felicijan@gmail.com> 2024-09-17 08:48:40 +0200
Committer Mitja Felicijan <mitja.felicijan@gmail.com> 2024-09-17 08:48:40 +0200
Commit fadbf136de03215a9bfaca04ee336b4085589de4 (patch)
-rw-r--r-- README.md 1
-rw-r--r-- zig-x11-box/Makefile 2
-rw-r--r-- zig-x11-box/main.zig 103
3 files changed, 106 insertions, 0 deletions
diff --git a/README.md b/README.md
...
19 
| [zig-telnet](./zig-telnet)       | Connects to Redis server like it is a basic telnet server.     |
 19 
| [zig-telnet](./zig-telnet)       | Connects to Redis server like it is a basic telnet server.     |
20 
| [zig-x11](./zig-x11)             | Uses X11 to create a basic window without any bindings needed. |
 20 
| [zig-x11](./zig-x11)             | Uses X11 to create a basic window without any bindings needed. |
21 
| [zig-http](./zig-http)           | Basic example of a HTTP 1.1 server without any routing etc.    |
 21 
| [zig-http](./zig-http)           | Basic example of a HTTP 1.1 server without any routing etc.    |
 
  
 22 
| [zig-x11-box](./zig-x11-box)     | Move a box around with arrow keys with Xlib and Zig.           |
diff --git a/zig-x11-box/Makefile b/zig-x11-box/Makefile 
  
 1 
default:
 
  
 2 
	zig run main.zig -lX11 -lc
diff --git a/zig-x11-box/main.zig b/zig-x11-box/main.zig 
  
 1 
// https://tronche.com/gui/x/xlib/
 
  
 2 
  
 
  
 3 
const std = @import("std");
 
  
 4 
const xlib = @cImport({
 
  
 5 
    @cInclude("X11/Xlib.h");
 
  
 6 
  
 
  
 7 
    // This should work and pull in header with all the mappings
 
  
 8 
    // making xlib.XK_Escape available but it doesn't.
 
  
 9 
    @cInclude("X11/keysymdef.h");
 
  
 10 
});
 
  
 11 
  
 
  
 12 
// Defining key symbols by hand from keysymdef.h file.
 
  
 13 
const KeySym = enum(u32) {
 
  
 14 
    ESCAPE = 0xFF1B,
 
  
 15 
    LEFT = 0xff51,
 
  
 16 
    UP = 0xff52,
 
  
 17 
    RIGHT = 0xff53,
 
  
 18 
    DOWN = 0xff54,
 
  
 19 
};
 
  
 20 
  
 
  
 21 
const Box = struct {
 
  
 22 
    x: i32,
 
  
 23 
    y: i32,
 
  
 24 
};
 
  
 25 
  
 
  
 26 
const StepSize = 30;
 
  
 27 
  
 
  
 28 
pub fn main() !void {
 
  
 29 
    const display = xlib.XOpenDisplay(null);
 
  
 30 
    if (display == null) {
 
  
 31 
        return error.DisplayOpenFailed;
 
  
 32 
    }
 
  
 33 
  
 
  
 34 
    const root_window = xlib.XDefaultRootWindow(display);
 
  
 35 
  
 
  
 36 
    const main_window = xlib.XCreateSimpleWindow(
 
  
 37 
        display,
 
  
 38 
        root_window,
 
  
 39 
        0,
 
  
 40 
        0,
 
  
 41 
        400,
 
  
 42 
        800,
 
  
 43 
        0,
 
  
 44 
        0,
 
  
 45 
        0xFFFFFF,
 
  
 46 
    );
 
  
 47 
  
 
  
 48 
    _ = xlib.XMapWindow(display, main_window);
 
  
 49 
    _ = xlib.XFlush(display);
 
  
 50 
  
 
  
 51 
    _ = xlib.XSelectInput(display, main_window, xlib.KeyPressMask);
 
  
 52 
    _ = xlib.XMapWindow(display, main_window);
 
  
 53 
  
 
  
 54 
    _ = xlib.XStoreName(display, main_window, "Moving boxes");
 
  
 55 
  
 
  
 56 
    var gc = xlib.XCreateGC(display, main_window, 0, null) orelse {
 
  
 57 
        std.debug.print("Failed to create graphics context\n", .{});
 
  
 58 
        return error.CreateGCFailed;
 
  
 59 
    };
 
  
 60 
    defer {
 
  
 61 
        _ = xlib.XFreeGC(display, gc);
 
  
 62 
    }
 
  
 63 
  
 
  
 64 
    var box = Box{ .x = 0, .y = 0 };
 
  
 65 
  
 
  
 66 
    var event: xlib.XEvent = undefined;
 
  
 67 
    while (true) {
 
  
 68 
        _ = xlib.XNextEvent(display, &event);
 
  
 69 
        if (event.type == xlib.KeyPress) {
 
  
 70 
            var keysym = xlib.XLookupKeysym(&event.xkey, 0);
 
  
 71 
  
 
  
 72 
            // NOTE: There probably is a better way of matching key presses
 
  
 73 
            //       without casting. I tried creating enum with type
 
  
 74 
            //       c_ulong without luck. More described in link below.
 
  
 75 
            //       https://ziglang.org/documentation/0.9.1/#Primitive-Types
 
  
 76 
  
 
  
 77 
            if (keysym == @intFromEnum(KeySym.ESCAPE)) {
 
  
 78 
                std.debug.print("Exiting game\n", .{});
 
  
 79 
                break;
 
  
 80 
            }
 
  
 81 
  
 
  
 82 
            if (keysym == @intFromEnum(KeySym.LEFT)) {
 
  
 83 
                box.x -= StepSize;
 
  
 84 
            }
 
  
 85 
  
 
  
 86 
            if (keysym == @intFromEnum(KeySym.RIGHT)) {
 
  
 87 
                box.x += StepSize;
 
  
 88 
            }
 
  
 89 
  
 
  
 90 
            if (keysym == @intFromEnum(KeySym.UP)) {
 
  
 91 
                box.y -= StepSize;
 
  
 92 
            }
 
  
 93 
  
 
  
 94 
            if (keysym == @intFromEnum(KeySym.DOWN)) {
 
  
 95 
                box.y += StepSize;
 
  
 96 
            }
 
  
 97 
        }
 
  
 98 
  
 
  
 99 
        _ = xlib.XClearWindow(display, main_window);
 
  
 100 
        _ = xlib.XDrawString(display, main_window, gc, 150, 150, "Use arrow keys.", 15);
 
  
 101 
        _ = xlib.XFillRectangle(display, main_window, gc, box.x, box.y, 100, 100);
 
  
 102 
    }
 
  
 103 
}