feat: add blurring capabilities (with_blur, set_blur) for Windows

Author: pml68

src/platform_impl/windows/window.rs

@@ -129,7 +129,16 @@ impl Window {
         });
     }
 
-    pub fn set_blur(&self, _blur: bool) {}
+    pub fn set_blur(&self, blur: bool) {
+        let window = self.window;
+        let window_state = Arc::clone(&self.window_state);
+        self.thread_executor.execute_in_thread(move || {
+            let _ = &window;
+            WindowState::set_window_flags(window_state.lock().unwrap(), window, |f| {
+                f.set(WindowFlags::BLUR, blur)
+            });
+        });
+    }
 
     #[inline]
     pub fn set_visible(&self, visible: bool) {
@@ -1233,10 +1242,16 @@ impl InitData<'_> {
     pub unsafe fn on_create(&mut self) {
         let win = self.window.as_mut().expect("failed window creation");
 
-        // making the window transparent
+        // making the window transparent and optionally blurred
         if self.attributes.transparent && !self.attributes.platform_specific.no_redirection_bitmap {
-            // Empty region for the blur effect, so the window is fully transparent
-            let region = unsafe { CreateRectRgn(0, 0, -1, -1) };
+            let region = unsafe {
+                if self.attributes.blur {
+                    0
+                } else {
+                    // Empty region for the blur effect, so the window is fully transparent
+                    CreateRectRgn(0, 0, -1, -1)
+                }
+            };
 
             let bb = DWM_BLURBEHIND {
                 dwFlags: DWM_BB_ENABLE | DWM_BB_BLURREGION,
@@ -1328,6 +1343,7 @@ unsafe fn init(
         .set(WindowFlags::NO_BACK_BUFFER, attributes.platform_specific.no_redirection_bitmap);
     window_flags.set(WindowFlags::MARKER_ACTIVATE, attributes.active);
     window_flags.set(WindowFlags::TRANSPARENT, attributes.transparent);
+    window_flags.set(WindowFlags::BLUR, attributes.blur);
     // WindowFlags::VISIBLE and MAXIMIZED are set down below after the window has been configured.
     window_flags.set(WindowFlags::RESIZABLE, attributes.resizable);
     // Will be changed later using `window.set_enabled_buttons` but we need to set a default here

src/platform_impl/windows/window_state.rs

@@ -92,36 +92,37 @@ bitflags! {
         const ALWAYS_ON_BOTTOM  = 1 << 7;
         const NO_BACK_BUFFER    = 1 << 8;
         const TRANSPARENT       = 1 << 9;
-        const CHILD             = 1 << 10;
-        const MAXIMIZED         = 1 << 11;
-        const POPUP             = 1 << 12;
+        const BLUR              = 1 << 10;
+        const CHILD             = 1 << 11;
+        const MAXIMIZED         = 1 << 12;
+        const POPUP             = 1 << 13;
 
         /// Marker flag for fullscreen. Should always match `WindowState::fullscreen`, but is
         /// included here to make masking easier.
-        const MARKER_EXCLUSIVE_FULLSCREEN = 1 << 13;
-        const MARKER_BORDERLESS_FULLSCREEN = 1 << 14;
+        const MARKER_EXCLUSIVE_FULLSCREEN = 1 << 14;
+        const MARKER_BORDERLESS_FULLSCREEN = 1 << 15;
 
         /// The `WM_SIZE` event contains some parameters that can effect the state of `WindowFlags`.
         /// In most cases, it's okay to let those parameters change the state. However, when we're
         /// running the `WindowFlags::apply_diff` function, we *don't* want those parameters to
         /// effect our stored state, because the purpose of `apply_diff` is to update the actual
         /// window's state to match our stored state. This controls whether to accept those changes.
-        const MARKER_RETAIN_STATE_ON_SIZE = 1 << 15;
+        const MARKER_RETAIN_STATE_ON_SIZE = 1 << 16;
 
-        const MARKER_IN_SIZE_MOVE = 1 << 16;
+        const MARKER_IN_SIZE_MOVE = 1 << 17;
 
-        const MINIMIZED = 1 << 17;
+        const MINIMIZED = 1 << 18;
 
-        const IGNORE_CURSOR_EVENT = 1 << 18;
+        const IGNORE_CURSOR_EVENT = 1 << 19;
 
         /// Fully decorated window (incl. caption, border and drop shadow).
-        const MARKER_DECORATIONS = 1 << 19;
+        const MARKER_DECORATIONS = 1 << 20;
         /// Drop shadow for undecorated windows.
-        const MARKER_UNDECORATED_SHADOW = 1 << 20;
+        const MARKER_UNDECORATED_SHADOW = 1 << 21;
 
-        const MARKER_ACTIVATE = 1 << 21;
+        const MARKER_ACTIVATE = 1 << 22;
 
-        const CLIP_CHILDREN = 1 << 22;
+        const CLIP_CHILDREN = 1 << 23;
 
         const EXCLUSIVE_FULLSCREEN_OR_MASK = WindowFlags::ALWAYS_ON_TOP.bits();
     }