macOS: Implement Moved (#478)

* macOS: Implement Moved

Fixes #67

* Also emit Moved after resizes that change position

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - Corrected `get_position` on Windows to be relative to the screen rather than to the taskbar.
 - Corrected `Moved` event on Windows to use position values equivalent to those returned by `get_position`. It previously supplied client area positions instead of window positions, and would additionally interpret negative values as being very large (around `u16::MAX`).
+- Implemented `Moved` event on macOS.
 
 # Version 0.13.1 (2018-04-26)
 

src/platform/macos/window.rs

@@ -43,6 +43,9 @@ struct DelegateState {
     // This is set when WindowBuilder::with_fullscreen was set,
     // see comments of `window_did_fail_to_enter_fullscreen`
     handle_with_fullscreen: bool,
+
+    // During windowDidResize, we use this to only send Moved if the position changed.
+    previous_position: Option<(i32, i32)>,
 }
 
 impl DelegateState {
@@ -161,6 +164,17 @@ impl WindowDelegate {
             emit_event(state, WindowEvent::Resized(width, height));
         }
 
+        unsafe fn emit_move_event(state: &mut DelegateState) {
+            let frame_rect = NSWindow::frame(*state.window);
+            let x = frame_rect.origin.x as _;
+            let y = Window2::bottom_left_to_top_left(frame_rect);
+            let moved = state.previous_position != Some((x, y));
+            if moved {
+                state.previous_position = Some((x, y));
+                emit_event(state, WindowEvent::Moved(x, y));
+            }
+        }
+
         extern fn window_should_close(this: &Object, _: Sel, _: id) -> BOOL {
             unsafe {
                 let state: *mut c_void = *this.get_ivar("winitState");
@@ -190,6 +204,16 @@ impl WindowDelegate {
                 let state: *mut c_void = *this.get_ivar("winitState");
                 let state = &mut *(state as *mut DelegateState);
                 emit_resize_event(state);
+                emit_move_event(state);
+            }
+        }
+
+        // This won't be triggered if the move was part of a resize.
+        extern fn window_did_move(this: &Object, _: Sel, _: id) {
+            unsafe {
+                let state: *mut c_void = *this.get_ivar("winitState");
+                let state = &mut *(state as *mut DelegateState);
+                emit_move_event(state);
             }
         }
 
@@ -377,6 +401,8 @@ impl WindowDelegate {
                 window_will_close as extern fn(&Object, Sel, id));
             decl.add_method(sel!(windowDidResize:),
                 window_did_resize as extern fn(&Object, Sel, id));
+            decl.add_method(sel!(windowDidMove:),
+                window_did_move as extern fn(&Object, Sel, id));
             decl.add_method(sel!(windowDidChangeScreen:),
                 window_did_change_screen as extern fn(&Object, Sel, id));
             decl.add_method(sel!(windowDidChangeBackingProperties:),
@@ -553,11 +579,12 @@ impl Window2 {
         let ds = DelegateState {
             view: view.clone(),
             window: window.clone(),
+            shared,
             win_attribs: RefCell::new(win_attribs.clone()),
             standard_frame: Cell::new(None),
             save_style_mask: Cell::new(None),
             handle_with_fullscreen: win_attribs.fullscreen.is_some(),
-            shared: shared,
+            previous_position: None,
         };
         ds.win_attribs.borrow_mut().fullscreen = None;