Add a global key callback

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "mosaic-tile"
-version = "0.2.1"
+version = "0.2.2"
 authors = ["Brooks J Rady <b.j.rady@gmail.com>"]
 edition = "2018"
 description = "A small client-side library for writing mosaic plugins (tiles)"

src/lib.rs

@@ -1,11 +1,12 @@
 mod shim;
 
 pub use shim::*;
-
+#[allow(unused_variables)]
 pub trait MosaicTile {
-    fn init(&mut self);
-    fn draw(&mut self, rows: usize, cols: usize);
-    fn handle_key(&mut self, key: Key);
+    fn init(&mut self) {}
+    fn draw(&mut self, rows: usize, cols: usize) {}
+    fn handle_key(&mut self, key: Key) {}
+    fn handle_global_key(&mut self, key: Key) {}
 }
 
 #[macro_export]
@@ -37,5 +38,12 @@ macro_rules! register_tile {
                 state.borrow_mut().handle_key(get_key());
             });
         }
+
+        #[no_mangle]
+        pub fn handle_global_key() {
+            STATE.with(|state| {
+                state.borrow_mut().handle_global_key(get_key());
+            });
+        }
     };
 }