Implement public API for high-DPI (#319)

* Implement public API for high-DPI #105

* Recover get_inner_size_points and get_inner_size_pixels and change their implementation assuming get_inner_size() returns size in pixels

* Update changelog for high-DPI changes

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Unreleased
 
+- Added event `WindowEvent::HiDPIFactorChanged`.
+- Added method `MonitorId::get_hidpi_factor`.
+- Deprecated `get_inner_size_pixels` and `get_inner_size_points` methods of `Window` in favor of
+`get_inner_size`.
+
 # Version 0.8.3 (2017-10-11)
 
 - Fixed issue of calls to `set_inner_size` blocking on Windows.

src/events.rs

@@ -87,6 +87,15 @@ pub enum WindowEvent {
 
     /// Touch event has been received
     Touch(Touch),
+
+    /// DPI scaling factor of the window has changed.
+    ///
+    /// The following actions cause DPI changes:
+    ///
+    /// * A user changes the resolution.
+    /// * A user changes the desktop scaling value (e.g. in Control Panel on Windows).
+    /// * A user moves the application window to a display with a different DPI.
+    HiDPIFactorChanged(f32),
 }
 
 /// Represents raw hardware events that are not associated with any particular window.

src/platform/android/mod.rs

@@ -164,6 +164,11 @@ impl MonitorId {
         // Android assumes single screen
         (0, 0)
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }
 
 #[derive(Clone, Default)]

src/platform/emscripten/mod.rs

@@ -42,6 +42,11 @@ impl MonitorId {
     pub fn get_dimensions(&self) -> (u32, u32) {
         (0, 0)
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }
 
 // Used to assign a callback to emscripten main loop

src/platform/ios/mod.rs

@@ -145,6 +145,11 @@ impl MonitorId {
         // iOS assumes single screen
         (0, 0)
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }
 
 pub struct EventsLoop {

src/platform/linux/mod.rs

@@ -94,6 +94,11 @@ impl MonitorId {
             &MonitorId::Wayland(ref m) => m.get_position(),
         }
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }
 
 impl Window {

src/platform/linux/wayland/context.rs

@@ -407,6 +407,11 @@ impl MonitorId {
         // if we reach here, this monitor does not exist any more
         (0,0)
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }
 
 // a handler to release the ressources acquired to draw the initial white screen as soon as

src/platform/linux/x11/monitor.rs

@@ -101,4 +101,9 @@ impl MonitorId {
     pub fn get_position(&self) -> (u32, u32) {
         self.position
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }

src/platform/linux/x11/window.rs

@@ -473,7 +473,7 @@ impl Window2 {
 
     #[inline]
     pub fn get_inner_size(&self) -> Option<(u32, u32)> {
-        self.get_geometry().map(|(_, _, w, h, _)| ((w as f32 / self.hidpi_factor()) as u32, (h as f32 / self.hidpi_factor()) as u32))
+        self.get_geometry().map(|(_, _, w, h, _)| (w, h))
     }
 
     #[inline]

src/platform/macos/monitor.rs

@@ -53,4 +53,9 @@ impl MonitorId {
     pub fn get_position(&self) -> (u32, u32) {
         unimplemented!()
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }

src/platform/windows/monitor.rs

@@ -181,4 +181,9 @@ impl MonitorId {
     pub fn get_position(&self) -> (u32, u32) {
         self.position
     }
+
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        1.0
+    }
 }

src/window.rs

@@ -91,7 +91,7 @@ impl WindowBuilder {
         self
     }
 
-    /// Enables multitouch
+    /// Enables multitouch.
     #[inline]
     pub fn with_multitouch(mut self) -> WindowBuilder {
         self.window.multitouch = true;
@@ -183,7 +183,7 @@ impl Window {
 
     /// Modifies the position of the window.
     ///
-    /// See `get_position` for more informations about the coordinates.
+    /// See `get_position` for more information about the coordinates.
     ///
     /// This is a no-op if the window has already been closed.
     #[inline]
@@ -191,14 +191,12 @@ impl Window {
         self.window.set_position(x, y)
     }
 
-    /// Returns the size in points of the client area of the window.
+    /// Returns the size in pixels of the client area of the window.
     ///
     /// The client area is the content of the window, excluding the title bar and borders.
-    /// To get the dimensions of the frame buffer when calling `glViewport`, multiply with hidpi factor.
+    /// These are the dimensions that need to be supplied to `glViewport`.
     ///
     /// Returns `None` if the window no longer exists.
-    ///
-    /// DEPRECATED
     #[inline]
     pub fn get_inner_size(&self) -> Option<(u32, u32)> {
         self.window.get_inner_size()
@@ -210,12 +208,17 @@ impl Window {
     /// To get the dimensions of the frame buffer when calling `glViewport`, multiply with hidpi factor.
     ///
     /// Returns `None` if the window no longer exists.
+    ///
+    /// DEPRECATED
     #[inline]
+    #[deprecated]
     pub fn get_inner_size_points(&self) -> Option<(u32, u32)> {
-        self.window.get_inner_size()
+        self.window.get_inner_size().map(|(x, y)| {
+            let hidpi = self.hidpi_factor();
+            ((x as f32 / hidpi) as u32, (y as f32 / hidpi) as u32)
+        })
     }
 
-
     /// Returns the size in pixels of the client area of the window.
     ///
     /// The client area is the content of the window, excluding the title bar and borders.
@@ -223,12 +226,12 @@ impl Window {
     ///  when you call `glViewport`.
     ///
     /// Returns `None` if the window no longer exists.
+    ///
+    /// DEPRECATED
     #[inline]
+    #[deprecated]
     pub fn get_inner_size_pixels(&self) -> Option<(u32, u32)> {
-        self.window.get_inner_size().map(|(x, y)| {
+        self.window.get_inner_size()
-            let hidpi = self.hidpi_factor();
-            ((x as f32 * hidpi) as u32, (y as f32 * hidpi) as u32)
-        })
     }
 
     /// Returns the size in pixels of the window.
@@ -244,7 +247,7 @@ impl Window {
 
     /// Modifies the inner size of the window.
     ///
-    /// See `get_inner_size` for more informations about the values.
+    /// See `get_inner_size` for more information about the values.
     ///
     /// This is a no-op if the window has already been closed.
     #[inline]
@@ -323,7 +326,7 @@ impl Window {
 }
 
 /// An iterator for the list of available monitors.
-// Implementation note: we retreive the list once, then serve each element by one by one.
+// Implementation note: we retrieve the list once, then serve each element by one by one.
 // This may change in the future.
 pub struct AvailableMonitorsIter {
     pub(crate) data: VecDequeIter<platform::MonitorId>,
@@ -370,4 +373,10 @@ impl MonitorId {
     pub fn get_position(&self) -> (u32, u32) {
         self.inner.get_position()
     }
+
+    /// Returns the ratio between the monitor's physical pixels and logical pixels.
+    #[inline]
+    pub fn get_hidpi_factor(&self) -> f32 {
+        self.inner.get_hidpi_factor()
+    }
 }