feat(borders): add border manager module

This commit removes all border-related code from process_command,
process_event etc. and centralizes it in the new border_manager module.

Instead of trying to figure out where in process_event and
process_command we should make border-related changes, a notification
gets sent to a channel that border_manager listens to whenever an event
or command has finished processing.

The border_manager listener, upon receiving a notification, acquires a
lock on the WindowManager instance and updates borders for the focused
workspace on every monitor; this allows us to centralize all edge case
handling within the border_manager listener's loop.

Borders on workspaces that lose focus are now destroyed and recreated
when those workspaces regain focus, instead of trying to share
individual border instances across workspaces.

A number of common edge cases that have been addressed in this commit
are:

* Paused window manager
* Floating workspaces
* Maximized windows
* Fullscreen videos
* Monocle containers
* Ghost borders on workspace switching
* Incorrect focused window border colours

Global state related to borders has also been moved into the
border_manager module, which also tracks the state of border objects
(BORDER_STATE), their rects (RECT_STATE) and their focus kinds
(FOCUS_STATE).

This allows us to now track multiple borders per-container, enabling
unfocused border windows for the first time.

Additionally, the Z-Order for border windows is now also configurable.

ActiveWindowBorderColours has been expanded to include Unfocused, but in
order to not introduce a breaking configuration change for end users,
all members of this struct have been made Option<Colour>.

Cargo.toml

@@ -18,6 +18,8 @@ dirs = "5"
 color-eyre = "0.6"
 serde_json = { package = "serde_json_lenient", version = "0.1" }
 sysinfo = "0.30"
+serde = { version = "1", features = ["derive"] }
+uds_windows = "1"
 
 [workspace.dependencies.windows]
 version = "0.54"

komorebi-core/src/lib.rs

@@ -218,6 +218,7 @@ pub enum WindowKind {
     Single,
     Stack,
     Monocle,
+    Unfocused,
 }
 
 #[derive(

komorebi/src/border_manager/border.rs

@@ -0,0 +1,204 @@
+use crate::border_manager::WindowKind;
+use crate::border_manager::BORDER_OFFSET;
+use crate::border_manager::BORDER_WIDTH;
+use crate::border_manager::FOCUSED;
+use crate::border_manager::FOCUS_STATE;
+use crate::border_manager::MONOCLE;
+use crate::border_manager::RECT_STATE;
+use crate::border_manager::STACK;
+use crate::border_manager::STYLE;
+use crate::border_manager::UNFOCUSED;
+use crate::border_manager::Z_ORDER;
+use crate::WindowsApi;
+use crate::WINDOWS_11;
+
+use komorebi_core::ActiveWindowBorderStyle;
+use komorebi_core::Rect;
+
+use std::sync::atomic::Ordering;
+use std::sync::mpsc;
+use std::time::Duration;
+use windows::core::PCWSTR;
+use windows::Win32::Foundation::COLORREF;
+use windows::Win32::Foundation::HWND;
+use windows::Win32::Foundation::LPARAM;
+use windows::Win32::Foundation::LRESULT;
+use windows::Win32::Foundation::WPARAM;
+use windows::Win32::Graphics::Gdi::BeginPaint;
+use windows::Win32::Graphics::Gdi::CreatePen;
+use windows::Win32::Graphics::Gdi::EndPaint;
+use windows::Win32::Graphics::Gdi::InvalidateRect;
+use windows::Win32::Graphics::Gdi::Rectangle;
+use windows::Win32::Graphics::Gdi::RoundRect;
+use windows::Win32::Graphics::Gdi::SelectObject;
+use windows::Win32::Graphics::Gdi::ValidateRect;
+use windows::Win32::Graphics::Gdi::PAINTSTRUCT;
+use windows::Win32::Graphics::Gdi::PS_INSIDEFRAME;
+use windows::Win32::Graphics::Gdi::PS_SOLID;
+use windows::Win32::UI::WindowsAndMessaging::DefWindowProcW;
+use windows::Win32::UI::WindowsAndMessaging::DispatchMessageW;
+use windows::Win32::UI::WindowsAndMessaging::GetMessageW;
+use windows::Win32::UI::WindowsAndMessaging::PostQuitMessage;
+use windows::Win32::UI::WindowsAndMessaging::TranslateMessage;
+use windows::Win32::UI::WindowsAndMessaging::CS_HREDRAW;
+use windows::Win32::UI::WindowsAndMessaging::CS_VREDRAW;
+use windows::Win32::UI::WindowsAndMessaging::MSG;
+use windows::Win32::UI::WindowsAndMessaging::WM_DESTROY;
+use windows::Win32::UI::WindowsAndMessaging::WM_PAINT;
+use windows::Win32::UI::WindowsAndMessaging::WNDCLASSW;
+
+pub struct Border {
+    pub hwnd: isize,
+}
+
+impl Border {
+    pub const fn hwnd(&self) -> HWND {
+        HWND(self.hwnd)
+    }
+
+    pub fn create(id: &str) -> color_eyre::Result<Self> {
+        let name: Vec<u16> = format!("komoborder-{id}\0").encode_utf16().collect();
+        let class_name = PCWSTR(name.as_ptr());
+
+        let h_module = WindowsApi::module_handle_w()?;
+
+        let window_class = WNDCLASSW {
+            hInstance: h_module.into(),
+            lpszClassName: class_name,
+            style: CS_HREDRAW | CS_VREDRAW,
+            lpfnWndProc: Some(Self::callback),
+            hbrBackground: WindowsApi::create_solid_brush(0),
+            ..Default::default()
+        };
+
+        let _ = WindowsApi::register_class_w(&window_class);
+
+        let (hwnd_sender, hwnd_receiver) = mpsc::channel();
+
+        std::thread::spawn(move || -> color_eyre::Result<()> {
+            let hwnd = WindowsApi::create_border_window(PCWSTR(name.as_ptr()), h_module)?;
+            hwnd_sender.send(hwnd)?;
+
+            let mut message = MSG::default();
+            unsafe {
+                while GetMessageW(&mut message, HWND(hwnd), 0, 0).into() {
+                    TranslateMessage(&message);
+                    DispatchMessageW(&message);
+                    std::thread::sleep(Duration::from_millis(10));
+                }
+            }
+
+            Ok(())
+        });
+
+        Ok(Self {
+            hwnd: hwnd_receiver.recv()?,
+        })
+    }
+
+    pub fn destroy(&self) -> color_eyre::Result<()> {
+        WindowsApi::destroy_window(self.hwnd())
+    }
+
+    pub fn update(&self, rect: &Rect) -> color_eyre::Result<()> {
+        // Make adjustments to the border
+        let mut rect = *rect;
+        rect.add_margin(BORDER_WIDTH.load(Ordering::SeqCst));
+        rect.add_padding(-BORDER_OFFSET.load(Ordering::SeqCst));
+
+        // Store the border rect so that it can be used by the callback
+        {
+            let mut rects = RECT_STATE.lock();
+            rects.insert(self.hwnd, rect);
+        }
+
+        // Update the position of the border
+        WindowsApi::set_border_pos(self.hwnd(), &rect, HWND((*Z_ORDER.lock()).into()))?;
+
+        // Invalidate the rect to trigger the callback to update colours etc.
+        self.invalidate();
+
+        Ok(())
+    }
+
+    pub fn invalidate(&self) {
+        let _ = unsafe { InvalidateRect(self.hwnd(), None, false) };
+    }
+
+    pub extern "system" fn callback(
+        window: HWND,
+        message: u32,
+        wparam: WPARAM,
+        lparam: LPARAM,
+    ) -> LRESULT {
+        unsafe {
+            match message {
+                WM_PAINT => {
+                    let rects = RECT_STATE.lock();
+
+                    // With the rect that we stored in Self::update
+                    if let Some(rect) = rects.get(&window.0).copied() {
+                        // Grab the focus kind for this border
+                        let focus_kind = {
+                            FOCUS_STATE
+                                .lock()
+                                .get(&window.0)
+                                .copied()
+                                .unwrap_or(WindowKind::Unfocused)
+                        };
+
+                        // Set up the brush to draw the border
+                        let mut ps = PAINTSTRUCT::default();
+                        let hdc = BeginPaint(window, &mut ps);
+                        let hpen = CreatePen(
+                            PS_SOLID | PS_INSIDEFRAME,
+                            BORDER_WIDTH.load(Ordering::SeqCst),
+                            COLORREF(match focus_kind {
+                                WindowKind::Unfocused => UNFOCUSED.load(Ordering::SeqCst),
+                                WindowKind::Single => FOCUSED.load(Ordering::SeqCst),
+                                WindowKind::Stack => STACK.load(Ordering::SeqCst),
+                                WindowKind::Monocle => MONOCLE.load(Ordering::SeqCst),
+                            }),
+                        );
+
+                        let hbrush = WindowsApi::create_solid_brush(0);
+
+                        // Draw the border
+                        SelectObject(hdc, hpen);
+                        SelectObject(hdc, hbrush);
+                        // TODO(raggi): this is approximately the correct curvature for
+                        // the top left of a Windows 11 window (DWMWCP_DEFAULT), but
+                        // often the bottom right has a different shape. Furthermore if
+                        // the window was made with DWMWCP_ROUNDSMALL then this is the
+                        // wrong size.  In the future we should read the DWM properties
+                        // of windows and attempt to match appropriately.
+                        match *STYLE.lock() {
+                            ActiveWindowBorderStyle::System => {
+                                if *WINDOWS_11 {
+                                    RoundRect(hdc, 0, 0, rect.right, rect.bottom, 20, 20);
+                                } else {
+                                    Rectangle(hdc, 0, 0, rect.right, rect.bottom);
+                                }
+                            }
+                            ActiveWindowBorderStyle::Rounded => {
+                                RoundRect(hdc, 0, 0, rect.right, rect.bottom, 20, 20);
+                            }
+                            ActiveWindowBorderStyle::Square => {
+                                Rectangle(hdc, 0, 0, rect.right, rect.bottom);
+                            }
+                        }
+                        EndPaint(window, &ps);
+                        ValidateRect(window, None);
+                    }
+
+                    LRESULT(0)
+                }
+                WM_DESTROY => {
+                    PostQuitMessage(0);
+                    LRESULT(0)
+                }
+                _ => DefWindowProcW(window, message, wparam, lparam),
+            }
+        }
+    }
+}