Merge pull request #88 from mitchmindtree/resize_cb_builder

Add a `WindowBuilder::with_window_resize_callback` method.

examples/window.rs

@@ -12,9 +12,11 @@ fn resize_callback(width: u32, height: u32) {
 }
 
 fn main() {
-    let mut window = winit::WindowBuilder::new().build().unwrap();
+    let window = winit::WindowBuilder::new()
-    window.set_title("A fantastic window!");
+        .with_title("A fantastic window!")
-    window.set_window_resize_callback(Some(resize_callback as fn(u32, u32)));
+        .with_window_resize_callback(resize_callback)
+        .build()
+        .unwrap();
 
     for event in window.wait_events() {
         println!("{:?}", event);

src/lib.rs

@@ -259,6 +259,10 @@ pub struct WindowAttributes {
     /// [iOS only] Enable multitouch, see [UIView#multipleTouchEnabled]
     /// (https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/#//apple_ref/occ/instp/UIView/multipleTouchEnabled)
     pub multitouch: bool,
+
+    /// A function called upon resizing, necessary to receive resize events on Mac and possibly
+    /// other systems.
+    pub resize_callback: Option<fn(u32, u32)>,
 }
 
 impl Default for WindowAttributes {
@@ -274,6 +278,7 @@ impl Default for WindowAttributes {
             transparent: false,
             decorations: true,
             multitouch: false,
+            resize_callback: None,
         }
     }
 }

src/window.rs

@@ -93,6 +93,15 @@ impl WindowBuilder {
         self
     }
 
+    /// Provides a resize callback that is called by Mac (and potentially other
+    /// operating systems) during resize operations. This can be used to repaint
+    /// during window resizing.
+    #[inline]
+    pub fn with_window_resize_callback(mut self, cb: fn(u32, u32)) -> WindowBuilder {
+        self.window.resize_callback = Some(cb);
+        self
+    }
+
     /// Builds the window.
     ///
     /// Error should be very rare and only occur in case of permission denied, incompatible system,
@@ -109,7 +118,14 @@ impl WindowBuilder {
         }
 
         // building
-        platform::Window::new(&self.window, &self.platform_specific).map(|w| Window { window: w })
+        let mut w = try!(platform::Window::new(&self.window, &self.platform_specific));
+
+        // a window resize callback was given
+        if let Some(callback) = self.window.resize_callback {
+            w.set_window_resize_callback(Some(callback));
+        }
+
+        Ok(Window { window: w })
     }
 
     /// Builds the window.