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Forked from NBonaparte/xcb.zig
Last active January 18, 2024 14:29
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Minimal XCB + Cairo example in Zig
//! Minimal XCB + Cairo example in Zig
//! Dependencies: libc, xcb, cairo
//! install XCB development files
//! sudo apt-get install libxcb1-dev
//! install cairo development files
//! sudo apt-get install libcairo2-dev
//! build and run with:
//! zig build-exe xcb.zig -lc -lxcb -lcairo && ./xcb
const std = @import("std");
const c = @cImport({
@cInclude("xcb/xcb.h");
@cInclude("cairo/cairo-xcb.h");
@cInclude("cairo/cairo.h");
});
/// Get the Id of the visual of a screen.
/// https://xcb.freedesktop.org/xlibtoxcbtranslationguide/
pub fn lookup_visual(s: *c.xcb_screen_t, visual: c.xcb_visualid_t) ?*c.xcb_visualtype_t {
var depth_iter = c.xcb_screen_allowed_depths_iterator(s);
// std.debug.print("TYPE INFO depth_iter: {}\n", .{@typeInfo(@TypeOf(depth_iter))});
while (depth_iter.rem != 0) {
var visual_iter = c.xcb_depth_visuals_iterator(depth_iter.data);
while (visual_iter.rem != 0) {
if (@ptrCast(*c.xcb_visualtype_t, visual_iter.data).visual_id == visual) {
return visual_iter.data;
}
c.xcb_visualtype_next(&visual_iter);
}
c.xcb_depth_next(&depth_iter);
}
return null;
}
pub fn main() void {
var display: ?[*]const u8 = null;
var screen: ?[*]c_int = null;
// std.debug.print("TYPE INFO screen: {}", .{@typeInfo(@TypeOf(screen))});
const conn = c.xcb_connect(display, screen);
// std.debug.print("TYPE INFO conn: {}\n", .{@typeInfo(@TypeOf(conn))});
defer c.xcb_disconnect(conn);
// we need to cast from unknown length pointer to single pointer because
// otherwise the zig compiler complains about not supporting field access.
const s = @ptrCast(*c.xcb_screen_t, c.xcb_setup_roots_iterator(c.xcb_get_setup(conn)).data);
// std.debug.print("TYPE INFO s: {}\n", .{@typeInfo(@TypeOf(s))});
// std.debug.print("TYPE INFO s.root {} s.root_visual {}\n", .{s.root, s.root_visual});
const window_id = c.xcb_generate_id(conn);
const x: i16 = 0;
const y: i16 = 0;
const width: u16 = 640;
const height: u16 = 480;
const border_width: u16 = 0;
const win_class: u16 = @as(u16, c.XCB_WINDOW_CLASS_INPUT_OUTPUT);
const depth = c.XCB_COPY_FROM_PARENT;
const mask = 0;
const values = null;
_ = c.xcb_create_window(conn, depth, window_id, s.root, x, y, width, height, border_width, win_class, s.root_visual, mask, values);
_ = c.xcb_map_window(conn, window_id);
_ = c.xcb_flush(conn);
const vis = lookup_visual(s, s.root_visual);
var surf = c.cairo_xcb_surface_create(conn, window_id, vis, width, height);
if (surf == null) return;
var ctx = c.cairo_create(surf);
_ = c.xcb_flush(conn);
// render loop
var toggle: bool = true;
while (true) {
if (toggle) {
c.cairo_set_source_rgb(ctx, 1.0, 0.65, 0); // orange
} else {
c.cairo_set_source_rgb(ctx, 0, 0, 0); // black
}
toggle = !toggle;
c.cairo_paint(ctx);
c.cairo_surface_flush(surf);
_ = c.xcb_flush(conn);
std.time.sleep(1e9);
}
}
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