task: rewrite event handling as a step towards event-based subscriptions

src/animations.rs

@@ -66,7 +66,9 @@ impl<T: Surface> IdleTask<T> {
 }
 
 impl<T: Surface> Task for IdleTask<T> {
-    fn start(&mut self) {
+    fn name(&self) -> &'static str { "Idle" }
+
+    fn start(&mut self, _bus: &mut EventBus) {
         self.solid.set_shader(Box::new(SolidShader { }));
         self.surface.set_shader(Box::new(ThinkingShader { }));
         self.shimmer.set_shader(Box::new(ShimmerShader { }));
@@ -76,9 +78,7 @@ impl<T: Surface> Task for IdleTask<T> {
         self.shimmer.set_opacity(64);
     }
 
-    fn tick(&mut self, event: &Event, bus: &mut EventBus) {}
-
-    fn stop(&mut self) {
+    fn stop(&mut self, _bus: &mut EventBus) {
         self.solid.clear_shader();
         self.surface.clear_shader();
         self.shimmer.clear_shader();
@@ -169,16 +169,19 @@ impl<T: Surface> TestPattern<T> {
 }
 
 impl<T: Surface> Task for TestPattern<T> {
-    fn start(&mut self) {
-        self.surface.set_shader(Box::new(self.pattern.clone()));
+    fn name(&self) -> &'static str { "TestPattern" }
+
+    fn start(&mut self, _bus: &mut EventBus) {
+        self.surface.set_shader(Box::new(self.pattern));
     }
 
-    fn tick(&mut self, event: &Event, bus: &mut EventBus) {
+    fn on_tick(&mut self, bus: &mut EventBus) {
         self.updater.run(|| {
             self.pattern = self.pattern.next();
             log::info!("Test pattern: {:?}", self.pattern);
             self.frame = 0;
-            self.surface.set_shader(Box::new(self.pattern.clone()));
+            self.surface.set_shader(Box::new(self.pattern));
+            bus.push(Event::new_property_change("animations.test.pattern", format!("{:?}", self.pattern)));
         });
         self.stepper.run(|| {
             self.frame = self.frame.wrapping_add(1);
@@ -197,7 +200,7 @@ impl<T: Surface> Task for TestPattern<T> {
         });
     }
 
-    fn stop(&mut self) {
+    fn stop(&mut self, _bus: &mut EventBus) {
         self.surface.clear_shader();
     }
 }