fix(clients/windows): hide the local cursor while captured

set_locked() hid the OS cursor with a one-shot ShowCursor(false), but the WinUI content island answers WM_SETCURSOR and re-asserts the arrow on every pointer move, so the cursor reappeared the instant the mouse moved while the pointer lock was engaged. A low-level mouse hook never sees WM_SETCURSOR, so it couldn't suppress it. Subclass the WinUI window and all its descendants (the video is a composition SwapChainPanel, so the pointer actually sits over WinUI's internal input-site child, which is the window that receives WM_SETCURSOR) and, while the lock wants the cursor hidden, answer WM_SETCURSOR ourselves with SetCursor(None) and return TRUE — halting WinUI's arrow re-assertion. ShowCursor(false) stays as the coarse first-frame hide. The subclass is removed on teardown so the reused app window (host list) is left pristine. Adds the Win32_UI_Shell feature for the subclassing APIs. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-08 16:45:20 +02:00
parent e28160ebb3
commit 0290bf7285
2 changed files with 88 additions and 5 deletions
@@ -42,6 +42,11 @@ windows = { git = "https://github.com/microsoft/windows-rs", rev = "a4f7b2cb7c63
    "Win32_System_Threading",
    "Win32_UI_HiDpi",
    "Win32_UI_Input_KeyboardAndMouse",
+    # Win32 window subclassing (SetWindowSubclass/DefSubclassProc) — the stream input hooks
+    # subclass the WinUI window + its content-island children to swallow WM_SETCURSOR so the
+    # local cursor stays hidden while the pointer is locked (WinUI otherwise re-asserts the arrow
+    # on every pointer move, defeating a one-shot ShowCursor(false)).
+    "Win32_UI_Shell",
    "Win32_UI_WindowsAndMessaging",
 ] }