Add API for transparency and decorations and add support for win32

examples/transparent.rs

@@ -0,0 +1,38 @@
+#[cfg(target_os = "android")]
+#[macro_use]
+extern crate android_glue;
+
+extern crate glutin;
+
+mod support;
+
+#[cfg(target_os = "android")]
+android_start!(main);
+
+#[cfg(not(feature = "window"))]
+fn main() { println!("This example requires glutin to be compiled with the `window` feature"); }
+
+#[cfg(feature = "window")]
+fn resize_callback(width: u32, height: u32) {
+    println!("Window resized to {}x{}", width, height);
+}
+
+#[cfg(feature = "window")]
+fn main() {
+    let mut window = glutin::WindowBuilder::new().with_decorations(false).with_transparency(true)
+                                                 .build().unwrap();
+    window.set_title("A fantastic window!");
+    window.set_window_resize_callback(Some(resize_callback as fn(u32, u32)));
+    unsafe { window.make_current() };
+
+    println!("Pixel format of the window: {:?}", window.get_pixel_format());
+
+    let context = support::load(&window);
+
+    while !window.is_closed() {
+        context.draw_frame((0.0, 0.0, 0.0, 0.0));
+        window.swap_buffers();
+
+        println!("{:?}", window.wait_events().next());
+    }
+}

src/api/win32/callback.rs

@@ -44,6 +44,7 @@ fn send_event(input_window: winapi::HWND, event: Event) {
 /// This is the callback that is called by `DispatchMessage` in the events loop.
 /// 
 /// Returning 0 tells the Win32 API that the message has been processed.
+// FIXME: detect WM_DWMCOMPOSITIONCHANGED and call DwmEnableBlurBehindWindow if necessary
 pub unsafe extern "system" fn callback(window: winapi::HWND, msg: winapi::UINT,
                                        wparam: winapi::WPARAM, lparam: winapi::LPARAM)
                                        -> winapi::LRESULT

src/api/win32/init.rs

@@ -102,7 +102,7 @@ unsafe fn init(title: Vec<u16>, builder: BuilderAttribs<'static>,
     }
 
     // computing the style and extended style of the window
-    let (ex_style, style) = if builder.monitor.is_some() {
+    let (ex_style, style) = if builder.monitor.is_some() || builder.decorations == false {
         (winapi::WS_EX_APPWINDOW, winapi::WS_POPUP | winapi::WS_CLIPSIBLINGS | winapi::WS_CLIPCHILDREN)
     } else {
         (winapi::WS_EX_APPWINDOW | winapi::WS_EX_WINDOWEDGE,
@@ -214,6 +214,27 @@ unsafe fn init(title: Vec<u16>, builder: BuilderAttribs<'static>,
         }
     };
 
+    // making the window transparent
+    if builder.transparent {
+        let bb = winapi::DWM_BLURBEHIND {
+            dwFlags: 0x1, // FIXME: DWM_BB_ENABLE;
+            fEnable: 1,
+            hRgnBlur: ptr::null_mut(),
+            fTransitionOnMaximized: 0,
+        };
+
+        let dll = kernel32::LoadLibraryA(b"dwmapi.dll\0".as_ptr() as *const _);
+        if !dll.is_null() {
+            let pr = kernel32::GetProcAddress(dll, b"DwmEnableBlurBehindWindow\0".as_ptr() as *const _);
+            if !pr.is_null() {
+                let pr: unsafe extern "system" fn(winapi::HWND, *const winapi::DWM_BLURBEHIND)
+                        -> winapi::HRESULT = mem::transmute(pr);
+                pr(real_window.0, &bb);
+            }
+            kernel32::FreeLibrary(dll);
+        }
+    }
+
     // calling SetForegroundWindow if fullscreen
     if builder.monitor.is_some() {
         user32::SetForegroundWindow(real_window.0);

src/lib.rs

@@ -295,6 +295,8 @@ pub struct BuilderAttribs<'a> {
     alpha_bits: Option<u8>,
     stereoscopy: bool,
     srgb: Option<bool>,
+    transparent: bool,
+    decorations: bool,
 }
 
 impl BuilderAttribs<'static> {
@@ -318,6 +320,8 @@ impl BuilderAttribs<'static> {
             alpha_bits: None,
             stereoscopy: false,
             srgb: None,
+            transparent: false,
+            decorations: true,
         }
     }
 }
@@ -346,6 +350,8 @@ impl<'a> BuilderAttribs<'a> {
             alpha_bits: self.alpha_bits,
             stereoscopy: self.stereoscopy,
             srgb: self.srgb,
+            transparent: self.transparent,
+            decorations: self.decorations,
         };
 
         (new_attribs, sharing)

src/window.rs

@@ -137,10 +137,22 @@ impl<'a> WindowBuilder<'a> {
         self
     }
 
+    /// Sets whether the background of the window should be transparent.
+    pub fn with_transparency(mut self, transparent: bool) -> WindowBuilder<'a> {
+        self.attribs.transparent = transparent;
+        self
+    }
+
+    /// Sets whether the window should have a border, a title bar, etc.
+    pub fn with_decorations(mut self, decorations: bool) -> WindowBuilder<'a> {
+        self.attribs.decorations = decorations;
+        self
+    }
+
     /// Builds the window.
     ///
     /// Error should be very rare and only occur in case of permission denied, incompatible system,
-    ///  out of memory, etc.
+    /// out of memory, etc.
     pub fn build(mut self) -> Result<Window, CreationError> {
         // resizing the window to the dimensions of the monitor when fullscreen
         if self.attribs.dimensions.is_none() && self.attribs.monitor.is_some() {