windows: handle WM_POINTERCAPTURECHANGED events, fix maybe-undefined …

…behavior. Fixes libsdl-org#11843. Fixes libsdl-org#11844.
icculus · Jan 6, 2025 · 896f0a2 · 896f0a2
1 parent c7584df
commit 896f0a2
Showing 1 changed file with 12 additions and 9 deletions.
diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
@@ -94,6 +94,9 @@
 #ifndef WM_POINTERLEAVE
 #define WM_POINTERLEAVE 0x024A
 #endif
+#ifndef WM_POINTERCAPTURECHANGED
+#define WM_POINTERCAPTURECHANGED 0x024C
+#endif
 #ifndef WM_UNICHAR
 #define WM_UNICHAR 0x0109
 #endif
@@ -1163,25 +1166,25 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
         returnCode = 0;
     } break;
 
+    case WM_POINTERCAPTURECHANGED:
     case WM_POINTERLEAVE:
     {
         const UINT32 pointerid = GET_POINTERID_WPARAM(wParam);
         void *hpointer = (void *) (size_t) pointerid;
         const SDL_PenID pen = SDL_FindPenByHandle(hpointer);
-        if (pen == 0) {
-            break;  // not a pen, or not a pen we already knew about.
-        }
-
-        // if this just left the _window_, we don't care. If this is no longer visible to the tablet, time to remove it!
-        if (!IS_POINTER_INCONTACT_WPARAM(wParam)) {
-            SDL_RemovePenDevice(WIN_GetEventTimestamp(), pen);
+        if (pen != 0) {
+            // if this just left the _window_, we don't care. If this is no longer visible to the tablet, time to remove it!
+            if ((msg == WM_POINTERCAPTURECHANGED) || !IS_POINTER_INCONTACT_WPARAM(wParam)) {
+                SDL_RemovePenDevice(WIN_GetEventTimestamp(), pen);
+            }
         }
         returnCode = 0;
     } break;
 
     case WM_POINTERUPDATE: {
         POINTER_INPUT_TYPE pointer_type = PT_POINTER;
         if (!data->videodata->GetPointerType || !data->videodata->GetPointerType(GET_POINTERID_WPARAM(wParam), &pointer_type)) {
+            returnCode = 0;
             break;  // oh well.
         }
 
@@ -1195,6 +1198,8 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
 
     case WM_POINTERDOWN:
     case WM_POINTERUP: {
+        returnCode = 0;  // always mark this event handled, so it doesn't go to DefWindowProc (see #11843).
+
         POINTER_PEN_INFO pen_info;
         const UINT32 pointerid = GET_POINTERID_WPARAM(wParam);
         void *hpointer = (void *) (size_t) pointerid;
@@ -1242,8 +1247,6 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
         if (msg == WM_POINTERDOWN) {
             SDL_SendPenTouch(timestamp, pen, window, (pen_info.penFlags & PEN_FLAG_INVERTED) != 0, true);
         }
-
-        returnCode = 0;
     } break;
 
     case WM_MOUSEMOVE: