Bug 1534389 - Send normal mouse events when cursor is over a draggabl…

…e region on Windows. r=jmathies Differential Revision: https://phabricator.services.mozilla.com/D23231
iaxat · Mar 18, 2019 · 52ea7e8 · 52ea7e8
1 parent 014f45f
commit 52ea7e8
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Showing 2 changed files with 35 additions and 16 deletions.
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
@@ -593,6 +593,7 @@ nsWindow::nsWindow(bool aIsChildWindow)
   mHideChrome = false;
   mFullscreenMode = false;
   mMousePresent = false;
+  mMouseInDraggableArea = false;
   mDestroyCalled = false;
   mIsEarlyBlankWindow = false;
   mHasTaskbarIconBeenCreated = false;
@@ -613,7 +614,7 @@ nsWindow::nsWindow(bool aIsChildWindow)
   mCachedHitTestPoint.x = 0;
   mCachedHitTestPoint.y = 0;
   mCachedHitTestTime = TimeStamp::Now();
-  mCachedHitTestResult = 0;
+  mCachedHitTestResult = false;
 #ifdef MOZ_XUL
   mTransparencyMode = eTransparencyOpaque;
   memset(&mGlassMargins, 0, sizeof mGlassMargins);
@@ -5300,6 +5301,8 @@ bool nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
       break;
 
     case WM_MOUSEMOVE: {
+      mMouseInDraggableArea =
+          WithinDraggableRegion(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
       if (!mMousePresent && !sIsInMouseCapture) {
         // First MOUSEMOVE over the client area. Ask for MOUSELEAVE
         TRACKMOUSEEVENT mTrack;
@@ -5332,12 +5335,19 @@ bool nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
       }
     } break;
 
-    case WM_NCMOUSEMOVE:
-      // If we receive a mouse move event on non-client chrome, make sure and
-      // send an eMouseExitFromWidget event as well.
-      if (mMousePresent && !sIsInMouseCapture)
+    case WM_NCMOUSEMOVE: {
+      LPARAM lParamClient = lParamToClient(lParam);
+      if (WithinDraggableRegion(GET_X_LPARAM(lParamClient),
+                                GET_Y_LPARAM(lParamClient))) {
+        // If we noticed the mouse moving in our draggable region, forward the
+        // message as a normal WM_MOUSEMOVE.
+        SendMessage(mWnd, WM_MOUSEMOVE, wParam, lParamClient);
+      } else if (mMousePresent && !sIsInMouseCapture) {
+        // If we receive a mouse move event on non-client chrome, make sure and
+        // send an eMouseExitFromWidget event as well.
         SendMessage(mWnd, WM_MOUSELEAVE, 0, 0);
-      break;
+      }
+    } break;
 
     case WM_LBUTTONDOWN: {
       result = DispatchMouseEvent(
@@ -5357,6 +5367,7 @@ bool nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
 
     case WM_MOUSELEAVE: {
       if (!mMousePresent) break;
+      if (mMouseInDraggableArea) break;
       mMousePresent = false;
 
       // Check if the mouse is over the fullscreen transition window, if so
@@ -6106,24 +6117,29 @@ int32_t nsWindow::ClientMarginHitTestPoint(int32_t mx, int32_t my) {
   if (!sIsInMouseCapture && allowContentOverride) {
     POINT pt = {mx, my};
     ::ScreenToClient(mWnd, &pt);
-    if (pt.x == mCachedHitTestPoint.x && pt.y == mCachedHitTestPoint.y &&
-        TimeStamp::Now() - mCachedHitTestTime <
-            TimeDuration::FromMilliseconds(HITTEST_CACHE_LIFETIME_MS)) {
-      return mCachedHitTestResult;
-    }
-    if (mDraggableRegion.Contains(pt.x, pt.y)) {
+    if (WithinDraggableRegion(pt.x, pt.y)) {
       testResult = HTCAPTION;
     } else {
       testResult = HTCLIENT;
     }
-    mCachedHitTestPoint = pt;
-    mCachedHitTestTime = TimeStamp::Now();
-    mCachedHitTestResult = testResult;
   }
 
   return testResult;
 }
 
+bool nsWindow::WithinDraggableRegion(int32_t clientX, int32_t clientY) {
+  if (clientX == mCachedHitTestPoint.x && clientY == mCachedHitTestPoint.y &&
+      TimeStamp::Now() - mCachedHitTestTime <
+          TimeDuration::FromMilliseconds(HITTEST_CACHE_LIFETIME_MS)) {
+    return mCachedHitTestResult;
+  }
+  mCachedHitTestPoint = {clientX, clientY};
+  mCachedHitTestTime = TimeStamp::Now();
+
+  mCachedHitTestResult = mDraggableRegion.Contains(clientX, clientY);
+  return mCachedHitTestResult;
+}
+
 TimeStamp nsWindow::GetMessageTimeStamp(LONG aEventTime) const {
   CurrentWindowsTimeGetter getCurrentTime(mWnd);
   return TimeConverter().GetTimeStampFromSystemTime(aEventTime, getCurrentTime);

diff --git a/widget/windows/nsWindow.h b/widget/windows/nsWindow.h
@@ -483,6 +483,7 @@ class nsWindow final : public nsWindowBase {
     return mTransparencyMode;
   }
   void UpdateGlass();
+  bool WithinDraggableRegion(int32_t clientX, int32_t clientY);
 
  protected:
 #endif  // MOZ_XUL
@@ -548,6 +549,7 @@ class nsWindow final : public nsWindowBase {
   bool mIsRTL;
   bool mFullscreenMode;
   bool mMousePresent;
+  bool mMouseInDraggableArea;
   bool mDestroyCalled;
   bool mOpeningAnimationSuppressed;
   bool mAlwaysOnTop;
@@ -659,6 +661,8 @@ class nsWindow final : public nsWindowBase {
   // Whether we we're created as a child window (aka ChildWindow) or not.
   bool mIsChildWindow : 1;
 
+  bool mCachedHitTestResult;
+
   // The point in time at which the last paint completed. We use this to avoid
   //  painting too rapidly in response to frequent input events.
   TimeStamp mLastPaintEndTime;
@@ -669,7 +673,6 @@ class nsWindow final : public nsWindowBase {
   // Caching for hit test results
   POINT mCachedHitTestPoint;
   TimeStamp mCachedHitTestTime;
-  int32_t mCachedHitTestResult;
 
   RefPtr<mozilla::widget::WinCompositorWidget> mBasicLayersSurface;