Merge pull request #453 from tomaka/transparency

Add API for transparency and decorations and add support for win32

4 files changed, 38 insertions, 2 deletions

diff --git a/src/api/win32/callback.rs b/src/api/win32/callback.rs
index 1ea95a5..86d5f1c 100644
--- a/src/api/win32/callback.rs
+++ b/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
diff --git a/src/api/win32/init.rs b/src/api/win32/init.rs
index fb4e181..f46c395 100644
--- a/src/api/win32/init.rs
+++ b/src/api/win32/init.rs
@@ -25,6 +25,7 @@ use std::sync::mpsc::channel;
 
 use winapi;
 use kernel32;
+use dwmapi;
 use user32;
 
 use api::wgl;
@@ -102,7 +103,7 @@ 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 +215,20 @@ 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,
+        };
+
+        unsafe {
+            dwmapi::DwmEnableBlurBehindWindow(real_window.0, &bb);
+        }
+    }
+
     // calling SetForegroundWindow if fullscreen
     if builder.monitor.is_some() {
         user32::SetForegroundWindow(real_window.0);
diff --git a/src/lib.rs b/src/lib.rs
index 1169513..612206e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -40,6 +40,8 @@ extern crate kernel32;
 extern crate gdi32;
 #[cfg(target_os = "windows")]
 extern crate user32;
+#[cfg(target_os = "windows")]
+extern crate dwmapi;
 #[cfg(target_os = "macos")]
 #[macro_use]
 extern crate objc;
@@ -295,6 +297,8 @@ pub struct BuilderAttribs<'a> {
     alpha_bits: Option<u8>,
     stereoscopy: bool,
     srgb: Option<bool>,
+    transparent: bool,
+    decorations: bool,
 }
 
 impl BuilderAttribs<'static> {
@@ -318,6 +322,8 @@ impl BuilderAttribs<'static> {
             alpha_bits: None,
             stereoscopy: false,
             srgb: None,
+            transparent: false,
+            decorations: true,
         }
     }
 }
@@ -346,6 +352,8 @@ impl<'a> BuilderAttribs<'a> {
             alpha_bits: self.alpha_bits,
             stereoscopy: self.stereoscopy,
             srgb: self.srgb,
+            transparent: self.transparent,
+            decorations: self.decorations,
         };
 
         (new_attribs, sharing)
diff --git a/src/window.rs b/src/window.rs
index c21b82d..578c237 100644
--- a/src/window.rs
+++ b/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() {