fix(macos::app_state): fix unwanted deviation when drag around monito…

…r boundaries (#923)

.changes/fix-macos-drag-deviation.md

@@ -0,0 +1,5 @@
+---
+"tao": patch
+---
+
+Fix unwanted deviation when dragging window around monitor boundaries on macOS.

src/platform_impl/macos/app_state.rs

@@ -226,21 +226,22 @@ impl Handler {
     scale_factor: f64,
   ) {
     let mut size = suggested_size.to_physical(scale_factor);
-    let new_inner_size = &mut size;
+    let old_size = size.clone();
     let event = Event::WindowEvent {
       window_id: WindowId(get_window_id(*ns_window)),
       event: WindowEvent::ScaleFactorChanged {
         scale_factor,
-        new_inner_size,
+        new_inner_size: &mut size,
       },
     };
 
     callback.handle_nonuser_event(event, &mut *self.control_flow.lock().unwrap());
 
-    let physical_size = *new_inner_size;
-    let logical_size = physical_size.to_logical(scale_factor);
-    let size = NSSize::new(logical_size.width, logical_size.height);
-    unsafe { NSWindow::setContentSize_(*ns_window, size) };
+    if old_size != size {
+      let logical_size = size.to_logical(scale_factor);
+      let size = NSSize::new(logical_size.width, logical_size.height);
+      unsafe { NSWindow::setContentSize_(*ns_window, size) };
+    }
   }
 
   fn handle_proxy(&self, proxy: EventProxy, callback: &mut Box<dyn EventHandler + 'static>) {