Add an example for (un-)grabbing the mouse cursor

examples/grabbing.rs

@@ -0,0 +1,50 @@
+#[cfg(target_os = "android")]
+#[macro_use]
+extern crate android_glue;
+
+extern crate glutin;
+
+use glutin::{Event, ElementState};
+
+mod support;
+
+#[cfg(target_os = "android")]
+android_start!(main);
+
+#[cfg(not(feature = "window"))]
+fn main() { println!("This example requires glutin to be compiled with the `window` feature"); }
+
+#[cfg(feature = "window")]
+fn main() {
+    
+    let window = glutin::Window::new().unwrap();
+    window.set_title("glutin - Cursor grabbing test");
+    unsafe { window.make_current() };
+
+    let context = support::load(&window);
+    let mut grabbed = false;
+    
+    while !window.is_closed() {
+        context.draw_frame((0.0, 1.0, 0.0, 1.0));
+        window.swap_buffers();
+
+        for event in window.poll_events() {
+            match event {
+                Event::KeyboardInput(ElementState::Pressed, _, _) => {
+                    if grabbed {
+                        grabbed = false;
+                        window.ungrab_cursor();
+                    }
+                    else {
+                        grabbed = true;
+                        window.grab_cursor().ok().expect("could not grab mouse cursor");
+                    }
+                },
+                _ => (),
+            }
+            
+        }
+        
+    }
+}
+