El2.0 ios (#871)

* port ios winit el2.0 implementation to the new rust-windowing repo

* unimplemented! => unreachable
trailing comma in CFRunLoopTimerCallback

* implement get_fullscreen

* add iOS specific platform documentation. Add a TODO about how to possibly extend the iOS backend to work have methods callable from more than just the main thread

* assert that window is only dropped from the main thread

* assert_main_thread called from fewer places

src/platform/ios.rs

@@ -2,7 +2,21 @@
 
 use std::os::raw::c_void;
 
-use {MonitorHandle, Window, WindowBuilder};
+use event_loop::EventLoop;
+use monitor::MonitorHandle;
+use window::{Window, WindowBuilder};
+
+/// Additional methods on `EventLoop` that are specific to iOS.
+pub trait EventLoopExtIOS {
+    /// Returns the idiom (phone/tablet/tv/etc) for the current device.
+    fn get_idiom(&self) -> Idiom;
+}
+
+impl<T: 'static> EventLoopExtIOS for EventLoop<T> {
+    fn get_idiom(&self) -> Idiom {
+        self.event_loop.get_idiom()
+    }
+}
 
 /// Additional methods on `Window` that are specific to iOS.
 pub trait WindowExtIOS {
@@ -11,10 +25,25 @@ pub trait WindowExtIOS {
     /// The pointer will become invalid when the `Window` is destroyed.
     fn get_uiwindow(&self) -> *mut c_void;
 
+    /// Returns a pointer to the `UIViewController` that is used by this window.
+    ///
+    /// The pointer will become invalid when the `Window` is destroyed.
+    fn get_uiviewcontroller(&self) -> *mut c_void;
+
     /// Returns a pointer to the `UIView` that is used by this window.
     ///
     /// The pointer will become invalid when the `Window` is destroyed.
     fn get_uiview(&self) -> *mut c_void;
+
+    /// Sets the HiDpi factor used by this window.
+    /// 
+    /// This translates to `-[UIWindow setContentScaleFactor:hidpi_factor]`.
+    fn set_hidpi_factor(&self, hidpi_factor: f64);
+
+    /// Sets the valid orientations for screens showing this `Window`.
+    /// 
+    /// On iPhones and iPods upside down portrait is never enabled.
+    fn set_valid_orientations(&self, valid_orientations: ValidOrientations);
 }
 
 impl WindowExtIOS for Window {
@@ -23,10 +52,25 @@ impl WindowExtIOS for Window {
         self.window.get_uiwindow() as _
     }
 
+    #[inline]
+    fn get_uiviewcontroller(&self) -> *mut c_void {
+        self.window.get_uiviewcontroller() as _
+    }
+
     #[inline]
     fn get_uiview(&self) -> *mut c_void {
         self.window.get_uiview() as _
     }
+
+    #[inline]
+    fn set_hidpi_factor(&self, hidpi_factor: f64) {
+        self.window.set_hidpi_factor(hidpi_factor)
+    }
+
+    #[inline]
+    fn set_valid_orientations(&self, valid_orientations: ValidOrientations) {
+        self.window.set_valid_orientations(valid_orientations)
+    }
 }
 
 /// Additional methods on `WindowBuilder` that are specific to iOS.
@@ -35,6 +79,15 @@ pub trait WindowBuilderExtIOS {
     ///
     /// The class will be initialized by calling `[root_view initWithFrame:CGRect]`
     fn with_root_view_class(self, root_view_class: *const c_void) -> WindowBuilder;
+    
+    /// Sets the `contentScaleFactor` of the underlying `UIWindow` to `hidpi_factor`.
+    /// 
+    /// The default value is device dependent, and it's recommended GLES or Metal applications set
+    /// this to `MonitorHandle::get_hidpi_factor()`.
+    fn with_hidpi_factor(self, hidpi_factor: f64) -> WindowBuilder;
+    
+    /// Sets the valid orientations for the `Window`.
+    fn with_valid_orientations(self, valid_orientations: ValidOrientations) -> WindowBuilder;
 }
 
 impl WindowBuilderExtIOS for WindowBuilder {
@@ -43,6 +96,18 @@ impl WindowBuilderExtIOS for WindowBuilder {
         self.platform_specific.root_view_class = unsafe { &*(root_view_class as *const _) };
         self
     }
+
+    #[inline]
+    fn with_hidpi_factor(mut self, hidpi_factor: f64) -> WindowBuilder {
+        self.platform_specific.hidpi_factor = Some(hidpi_factor);
+        self
+    }
+
+    #[inline]
+    fn with_valid_orientations(mut self, valid_orientations: ValidOrientations) -> WindowBuilder {
+        self.platform_specific.valid_orientations = valid_orientations;
+        self
+    }
 }
 
 /// Additional methods on `MonitorHandle` that are specific to iOS.
@@ -57,3 +122,40 @@ impl MonitorHandleExtIOS for MonitorHandle {
         self.inner.get_uiscreen() as _
     }
 }
+
+/// Valid orientations for a particular `Window`.
+#[derive(Clone, Copy, Debug)]
+pub enum ValidOrientations {
+    /// Excludes `PortraitUpsideDown` on iphone
+    LandscapeAndPortrait,
+
+    Landscape,
+    
+    /// Excludes `PortraitUpsideDown` on iphone
+    Portrait,
+}
+
+impl Default for ValidOrientations {
+    #[inline]
+    fn default() -> ValidOrientations {
+        ValidOrientations::LandscapeAndPortrait
+    }
+}
+
+/// The device [idiom].
+/// 
+/// [idiom]: https://developer.apple.com/documentation/uikit/uidevice/1620037-userinterfaceidiom?language=objc
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Idiom {
+    Unspecified,
+
+    /// iPhone and iPod touch.
+    Phone,
+
+    /// iPad.
+    Pad,
+
+    /// tvOS and Apple TV.
+    TV,
+    CarPlay,
+}