On Windows, add drag_resize_window method support (#2966)

CHANGELOG.md

@@ -24,6 +24,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - On Web, implement `Window::focus_window()`.
 - On Web, remove unnecessary `Window::is_dark_mode()`, which was replaced with `Window::theme()`.
 - On Web, add `WindowBuilderExtWebSys::with_append()` to append the canvas element to the web page on creation.
+- On Windows, add `drag_resize_window` method support.
 
 # 0.29.0-beta.0
 

FEATURES.md

@@ -217,7 +217,7 @@ Legend:
 |Gamepad/Joystick events |❌[#804] |❌      |❌       |❌          |❌    |❌     |❓        |**N/A** |
 |Device movement events  |❓        |❓       |❓       |❓           |❌    |❌     |❓        |**N/A** |
 |Drag window with cursor |✔️       |✔️      |✔️       |✔️          |**N/A**|**N/A**|**N/A**   |**N/A** |
-|Resize with cursor      |❌         |❌       |✔️       |❌       |**N/A**|**N/A**|**N/A**   |**N/A** |
+|Resize with cursor      |✔️       |❌       |✔️       |✔️       |**N/A**|**N/A**|**N/A**   |**N/A** |
 
 ### Pending API Reworks
 Changes in the API that have been agreed upon but aren't implemented across all platforms.

src/platform_impl/windows/window.rs

@@ -46,7 +46,8 @@ use windows_sys::Win32::{
             IsWindowVisible, LoadCursorW, PeekMessageW, PostMessageW, RegisterClassExW, SetCursor,
             SetCursorPos, SetForegroundWindow, SetWindowDisplayAffinity, SetWindowPlacement,
             SetWindowPos, SetWindowTextW, CS_HREDRAW, CS_VREDRAW, CW_USEDEFAULT, FLASHWINFO,
-            FLASHW_ALL, FLASHW_STOP, FLASHW_TIMERNOFG, FLASHW_TRAY, GWLP_HINSTANCE, HTCAPTION,
+            FLASHW_ALL, FLASHW_STOP, FLASHW_TIMERNOFG, FLASHW_TRAY, GWLP_HINSTANCE, HTBOTTOM,
+            HTBOTTOMLEFT, HTBOTTOMRIGHT, HTCAPTION, HTLEFT, HTRIGHT, HTTOP, HTTOPLEFT, HTTOPRIGHT,
             NID_READY, PM_NOREMOVE, SM_DIGITIZER, SWP_ASYNCWINDOWPOS, SWP_NOACTIVATE, SWP_NOSIZE,
             SWP_NOZORDER, WDA_EXCLUDEFROMCAPTURE, WDA_NONE, WM_NCLBUTTONDOWN, WNDCLASSEXW,
         },
@@ -410,36 +411,53 @@ impl Window {
         Ok(())
     }
 
+    unsafe fn handle_os_dragging(&self, wparam: WPARAM) {
+        let points = {
+            let mut pos = mem::zeroed();
+            GetCursorPos(&mut pos);
+            pos
+        };
+        let points = POINTS {
+            x: points.x as i16,
+            y: points.y as i16,
+        };
+        ReleaseCapture();
+
+        self.window_state_lock().dragging = true;
+
+        PostMessageW(
+            self.hwnd(),
+            WM_NCLBUTTONDOWN,
+            wparam,
+            &points as *const _ as LPARAM,
+        );
+    }
+
     #[inline]
     pub fn drag_window(&self) -> Result<(), ExternalError> {
         unsafe {
-            let points = {
-                let mut pos = mem::zeroed();
-                GetCursorPos(&mut pos);
-                pos
-            };
-            let points = POINTS {
-                x: points.x as i16,
-                y: points.y as i16,
-            };
-            ReleaseCapture();
-
-            self.window_state_lock().dragging = true;
-
-            PostMessageW(
-                self.hwnd(),
-                WM_NCLBUTTONDOWN,
-                HTCAPTION as WPARAM,
-                &points as *const _ as LPARAM,
-            );
+            self.handle_os_dragging(HTCAPTION as WPARAM);
         }
 
         Ok(())
     }
 
     #[inline]
-    pub fn drag_resize_window(&self, _direction: ResizeDirection) -> Result<(), ExternalError> {
-        Err(ExternalError::NotSupported(NotSupportedError::new()))
+    pub fn drag_resize_window(&self, direction: ResizeDirection) -> Result<(), ExternalError> {
+        unsafe {
+            self.handle_os_dragging(match direction {
+                ResizeDirection::East => HTRIGHT,
+                ResizeDirection::North => HTTOP,
+                ResizeDirection::NorthEast => HTTOPRIGHT,
+                ResizeDirection::NorthWest => HTTOPLEFT,
+                ResizeDirection::South => HTBOTTOM,
+                ResizeDirection::SouthEast => HTBOTTOMRIGHT,
+                ResizeDirection::SouthWest => HTBOTTOMLEFT,
+                ResizeDirection::West => HTLEFT,
+            } as WPARAM);
+        }
+
+        Ok(())
     }
 
     #[inline]

src/window.rs

@@ -1299,7 +1299,8 @@ impl Window {
     ///
     /// ## Platform-specific
     ///
-    /// Only X11 is supported at this time.
+    /// - **macOS:** Always returns an [`ExternalError::NotSupported`]
+    /// - **iOS / Android / Web / Orbital:** Always returns an [`ExternalError::NotSupported`].
     #[inline]
     pub fn drag_resize_window(&self, direction: ResizeDirection) -> Result<(), ExternalError> {
         self.window.drag_resize_window(direction)