Started with implementing get_size()

Currently Mac is implemented with stub versions for Linux and Windows

src/lib.rs

@@ -251,6 +251,21 @@ impl Window {
         self.0.set_position(x, y)
     }
 
+    ///
+    /// Returns the current size of the window
+    ///
+    /// # Examples
+    ///
+    /// ```ignore
+    /// let size = window.get_size();
+    /// println!("width {} height {}", size.0, size.1);
+    /// ```
+    ///
+    #[inline]
+    pub fn get_size(&self) -> (usize, usize) {
+        self.0.get_size()
+    }
+
     ///
     /// Get the current position of the mouse relative to the current window
     /// The coordinate system is as 0, 0 as the upper left corner

src/native/macosx/OSXWindowFrameView.m

@@ -95,5 +95,32 @@
     return YES;
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+- (void)viewDidMoveToWindow
+{
+	[[NSNotificationCenter defaultCenter] addObserver:self
+	selector:@selector(windowResized:) name:NSWindowDidResizeNotification
+	object:[self window]];
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+- (void)dealloc
+{
+	[[NSNotificationCenter defaultCenter] removeObserver:self];
+	[super dealloc];
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+- (void)windowResized:(NSNotification *)notification;
+{
+	NSSize size = [[self window] frame].size;
+    OSXWindow* window = (OSXWindow*)[self window];
+    window->shared_data->width = (int)size.width;
+    window->shared_data->height = (int)size.height;
+}
+
 @end
 

src/os/macos/mod.rs

@@ -280,6 +280,10 @@ impl Window {
         unsafe { mfb_set_position(self.window_handle, x as i32, y as i32) }
     }
 
+    pub fn get_size(&self) -> (usize, usize) {
+        (self.shared_data.width as usize, self.shared_data.height as usize)
+    }
+
     pub fn get_scroll_wheel(&self) -> Option<(f32, f32)> {
         let sx = self.shared_data.scroll_x;
         let sy = self.shared_data.scroll_y;

src/os/unix/mod.rs

@@ -233,6 +233,11 @@ impl Window {
         unsafe { mfb_set_position(self.window_handle, x as i32, y as i32) }
     }
 
+    #[inline]
+    pub fn get_size(&self) -> (usize, usize) {
+        (0, 0)
+    }
+
     pub fn get_mouse_pos(&self, mode: MouseMode) -> Option<(f32, f32)> {
         let s = self.shared_data.scale as f32;
         let w = self.shared_data.width as f32;

src/os/windows/mod.rs

@@ -465,6 +465,11 @@ impl Window {
         }
     }
 
+    #[inline]
+    pub fn get_size(&self) -> (usize, usize) {
+        (0, 0)
+    }
+
     pub fn get_mouse_pos(&self, mode: MouseMode) -> Option<(f32, f32)> {
         let s = self.scale_factor as f32;
         let w = self.width as f32;