Changeset 109151 in webkit

Timestamp:

Feb 28, 2012 2:26:24 PM (12 years ago)

Author:

commit-queue@webkit.org

Message:

Slow content causes choppy scrolling
​https://bugs.webkit.org/show_bug.cgi?id=79403

Patch by Dave Moore <​davemoore@chromium.org> on 2012-02-28
Reviewed by James Robinson.

This code helps make scrolling (via wheel or pad) less choppy
when the content takes a long time to respond to the fake mouse moves
generated during scrolls.

• page/EventHandler.cpp:

(WebCore):
(MaximumDurationTracker):
(WebCore::MaximumDurationTracker::MaximumDurationTracker):
(WebCore::MaximumDurationTracker::~MaximumDurationTracker):
(WebCore::EventHandler::EventHandler):
(WebCore::EventHandler::clear):
(WebCore::EventHandler::mouseMoved):
(WebCore::EventHandler::dispatchFakeMouseMoveEventSoon):
(WebCore::EventHandler::dispatchFakeMouseMoveEventSoonInQuad):

• page/EventHandler.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• page/EventHandler.cpp (modified) (7 diffs)
• page/EventHandler.h (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2012-02-28  Dave Moore  <davemoore@chromium.org>
+
+        Slow content causes choppy scrolling
+        https://bugs.webkit.org/show_bug.cgi?id=79403
+
+        Reviewed by James Robinson.
+
+        This code helps make scrolling (via wheel or pad) less choppy
+        when the content takes a long time to respond to the fake mouse moves
+        generated during scrolls.
+
+
+ * page/EventHandler.cpp:
+        (WebCore):
+        (MaximumDurationTracker):
+        (WebCore::MaximumDurationTracker::MaximumDurationTracker):
+        (WebCore::MaximumDurationTracker::~MaximumDurationTracker):
+        (WebCore::EventHandler::EventHandler):
+        (WebCore::EventHandler::clear):
+        (WebCore::EventHandler::mouseMoved):
+        (WebCore::EventHandler::dispatchFakeMouseMoveEventSoon):
+        (WebCore::EventHandler::dispatchFakeMouseMoveEventSoonInQuad):
+        * page/EventHandler.h:
+
 2012-02-28  Andreas Kling  <awesomekling@apple.com>
 

trunk/Source/WebCore/page/EventHandler.cpp

@@ -127 +127 @@
 const double autoscrollInterval = 0.05;
 
-const double fakeMouseMoveInterval = 0.1;
+// The amount of time to wait before sending a fake mouse event, triggered
+// during a scroll. The short interval is used if the content responds to the mouse events quickly enough,
+// otherwise the long interval is used.
+const double fakeMouseMoveShortInterval = 0.1;
+const double fakeMouseMoveLongInterval = 0.250;
 
 enum NoCursorChangeType { NoCursorChange };
@@ -142 +146 @@
     bool m_isCursorChange;
     Cursor m_cursor;
+};
+
+class MaximumDurationTracker {
+public:
+    explicit MaximumDurationTracker(double *maxDuration)
+        : m_maxDuration(maxDuration)
+        , m_start(monotonicallyIncreasingTime())
+    {
+    }
+
+    ~MaximumDurationTracker()
+    {
+        *m_maxDuration = max(*m_maxDuration, monotonicallyIncreasingTime() - m_start);
+    }
+
+private:
+    double* m_maxDuration;
+    double m_start;
 };
 
@@ -290 +312 @@
     , m_touchPressed(false)
 #endif
+    , m_maxMouseMovedDuration(0)
 {
 }
@@ -336 +359 @@
     m_originatingTouchPointTargets.clear();
 #endif
+    m_maxMouseMovedDuration = 0;
 }
 
@@ -1636 +1660 @@
 bool EventHandler::mouseMoved(const PlatformMouseEvent& event)
 {
+    MaximumDurationTracker maxDurationTracker(&m_maxMouseMovedDuration);
     RefPtr<FrameView> protector(m_frame->view());
+
 
 #if ENABLE(TOUCH_EVENTS)
@@ -2500 +2526 @@
         return;
 
-    if (!m_fakeMouseMoveEventTimer.isActive())
-        m_fakeMouseMoveEventTimer.startOneShot(fakeMouseMoveInterval);
+    // If the content has ever taken longer than fakeMouseMoveShortInterval we
+    // reschedule the timer and use a longer time. This will cause the content
+    // to receive these moves only after the user is done scrolling, reducing
+    // pauses during the scroll.
+    if (m_maxMouseMovedDuration > fakeMouseMoveShortInterval) {
+        if (m_fakeMouseMoveEventTimer.isActive())
+            m_fakeMouseMoveEventTimer.stop();
+        m_fakeMouseMoveEventTimer.startOneShot(fakeMouseMoveLongInterval);
+    } else {
+        if (!m_fakeMouseMoveEventTimer.isActive())
+            m_fakeMouseMoveEventTimer.startOneShot(fakeMouseMoveShortInterval);
+    }
 }
 
@@ -2510 +2546 @@
         return;
 
-    if (m_mousePressed || !quad.containsPoint(view->windowToContents(m_currentMousePosition)))
+    if (!quad.containsPoint(view->windowToContents(m_currentMousePosition)))
         return;
 
-    if (!m_fakeMouseMoveEventTimer.isActive())
-        m_fakeMouseMoveEventTimer.startOneShot(fakeMouseMoveInterval);
+    dispatchFakeMouseMoveEventSoon();
 }
 

trunk/Source/WebCore/page/EventHandler.h

@@ -432 +432 @@
     bool m_touchPressed;
 #endif
+    double m_maxMouseMovedDuration;
 };