Fix and publish X11 screen id

examples/window.rs

@@ -4,22 +4,28 @@ use simple_logger::SimpleLogger;
 use winit::{
     event::{Event, WindowEvent},
     event_loop::EventLoop,
+    platform::unix::WindowBuilderExtUnix,
     window::WindowBuilder,
 };
 
 fn main() {
-    SimpleLogger::new().init().unwrap();
+    let screen_number = std::env::args()
+        .nth(1)
+        .expect("please specify screen number to run on as first commandline argument")
+        .parse()
+        .expect("could not parse first commandline argument as i32");
+
+    SimpleLogger::new().env().init().unwrap();
     let event_loop = EventLoop::new();
 
-    let window = WindowBuilder::new()
+    let window_builder = WindowBuilder::new()
         .with_title("A fantastic window!")
-        .with_inner_size(winit::dpi::LogicalSize::new(128.0, 128.0))
-        .build(&event_loop)
-        .unwrap();
+        .with_inner_size(winit::dpi::LogicalSize::new(500.0, 500.0))
+        .with_x11_screen(screen_number);
+    let window = window_builder.build(&event_loop).unwrap();
 
     event_loop.run(move |event, _, control_flow| {
         control_flow.set_wait();
-        println!("{:?}", event);
 
         match event {
             Event::WindowEvent {

src/platform_impl/linux/x11/window.rs

@@ -120,7 +120,10 @@ impl UnownedWindow {
         pl_attribs: PlatformSpecificWindowBuilderAttributes,
     ) -> Result<UnownedWindow, RootOsError> {
         let xconn = &event_loop.xconn;
-        let root = event_loop.root;
+        let root = match pl_attribs.screen_id {
+            Some(screen_id) => unsafe { (xconn.xlib.XRootWindow)(xconn.display, screen_id) },
+            None => event_loop.root,
+        };
 
         let mut monitors = xconn.available_monitors();
         let guessed_monitor = if monitors.is_empty() {

src/window.rs

@@ -107,7 +107,7 @@ pub struct WindowBuilder {
     pub(crate) window: WindowAttributes,
 
     // Platform-specific configuration.
-    pub(crate) platform_specific: platform_impl::PlatformSpecificWindowBuilderAttributes,
+    pub platform_specific: platform_impl::PlatformSpecificWindowBuilderAttributes,
 }
 
 impl fmt::Debug for WindowBuilder {