Added notifications in NSViewComponent so that its childBoundsChanged method will be called if the embedded NSView changes bounds.

modules/juce_gui_extra/native/juce_mac_NSViewComponent.mm

@@ -28,18 +28,30 @@ class NSViewAttachment  : public ReferenceCountedObject,
 public:
     NSViewAttachment (NSView* const v, Component& comp)
         : ComponentMovementWatcher (&comp),
-          view (v),
-          owner (comp),
-          currentPeer (nullptr)
+          view (v), owner (comp),
+          currentPeer (nullptr), frameChangeCallback (nullptr)
     {
         [view retain];
+        [view setPostsFrameChangedNotifications: YES];
 
         if (owner.isShowing())
             componentPeerChanged();
+
+        static ViewFrameChangeCallbackClass cls;
+        frameChangeCallback = [cls.createInstance() init];
+        ViewFrameChangeCallbackClass::setTarget (frameChangeCallback, &owner);
+
+        [[NSNotificationCenter defaultCenter]  addObserver: frameChangeCallback
+                                                  selector: @selector (frameChanged:)
+                                                      name: NSViewFrameDidChangeNotification
+                                                    object: view];
     }
 
     ~NSViewAttachment()
     {
+        [[NSNotificationCenter defaultCenter] removeObserver: frameChangeCallback];
+        [frameChangeCallback release];
+
         removeFromParent();
         [view release];
     }
@@ -96,6 +108,7 @@ public:
 private:
     Component& owner;
     ComponentPeer* currentPeer;
+    id frameChangeCallback;
 
     void removeFromParent()
     {
@@ -104,6 +117,31 @@ private:
                                         // override the call and use it as a sign that they're being deleted, which breaks everything..
     }
 
+    //==============================================================================
+    struct ViewFrameChangeCallbackClass   : public ObjCClass<NSObject>
+    {
+        ViewFrameChangeCallbackClass()  : ObjCClass<NSObject> ("JUCE_NSViewCallback_")
+        {
+            addIvar<Component*> ("target");
+            addMethod (@selector (frameChanged:),  frameChanged, "v@:@");
+            registerClass();
+        }
+
+        static void setTarget (id self, Component* c)
+        {
+            object_setInstanceVariable (self, "target", c);
+        }
+
+    private:
+        static void frameChanged (id self, SEL, NSNotification*)
+        {
+            if (Component* const target = getIvar<Component*> (self, "target"))
+                target->childBoundsChanged (nullptr);
+        }
+
+        JUCE_DECLARE_NON_COPYABLE (ViewFrameChangeCallbackClass);
+    };
+
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (NSViewAttachment)
 };
 
@@ -124,7 +162,7 @@ void NSViewComponent::setView (void* const view)
 
 void* NSViewComponent::getView() const
 {
-    return attachment != nullptr ? static_cast <NSViewAttachment*> (attachment.get())->view
+    return attachment != nullptr ? static_cast<NSViewAttachment*> (attachment.get())->view
                                  : nullptr;
 }
 
@@ -132,7 +170,7 @@ void NSViewComponent::resizeToFitView()
 {
     if (attachment != nullptr)
     {
-        NSRect r = [static_cast <NSViewAttachment*> (attachment.get())->view frame];
+        NSRect r = [static_cast<NSViewAttachment*> (attachment.get())->view frame];
         setBounds (Rectangle<int> ((int) r.size.width, (int) r.size.height));
     }
 }