Changeset 167560 in webkit

Timestamp:

Apr 19, 2014 7:32:48 PM (10 years ago)

Author:

Brent Fulgham

Message:

Latched scrolling may interact badly with custom programmatic scrolling
​https://bugs.webkit.org/show_bug.cgi?id=131869
<rdar://problem/16249557>

Reviewed by Darin Adler.

• dom/Element.cpp:

(WebCore::Element::setScrollLeft): Mark scrollable area as having
been scrolled programmatically.
(WebCore::Element::setScrollTop): Ditto.

• page/EventHandler.cpp:

(WebCore::EventHandler::handleWheelEvent): Check for programmatic scroll, and
clear latched state if the handler manually scrolled. Clear programmatic
scroll state at the end of event handling.
(WebCore::EventHandler::clearLatchedState): Refactored code.

• page/EventHandler.h:
• page/mac/EventHandlerMac.mm:

(WebCore::EventHandler::platformPrepareForWheelEvents): Check
if scrollable area was scrolled programmatically. If it was, do
not honor latching behavior.

• platform/ScrollableArea.cpp:

(WebCore::ScrollableArea::ScrollableArea): Initialize new member.

• platform/ScrollableArea.h:

(WebCore::ScrollableArea::isScrolledProgrammatically): Added.
(WebCore::ScrollableArea::setScrolledProgrammatically): Added.

Location:

trunk

Files:

• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/dom/Element.cpp (modified) (3 diffs)
• Source/WebCore/page/EventHandler.cpp (modified) (2 diffs)
• Source/WebCore/page/EventHandler.h (modified) (1 diff)
• Source/WebCore/page/mac/EventHandlerMac.mm (modified) (1 diff)
• Source/WebCore/platform/ScrollableArea.cpp (modified) (1 diff)
• Source/WebCore/platform/ScrollableArea.h (modified) (2 diffs)
• WebKit.xcworkspace/xcshareddata/xcschemes/All Source (target WebProcess).xcscheme (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2014-04-19  Brent Fulgham  <bfulgham@apple.com>
+
+        Latched scrolling may interact badly with custom programmatic scrolling
+        https://bugs.webkit.org/show_bug.cgi?id=131869
+        <rdar://problem/16249557>
+
+        Reviewed by Darin Adler.
+
+        * dom/Element.cpp:
+        (WebCore::Element::setScrollLeft): Mark scrollable area as having
+        been scrolled programmatically.
+        (WebCore::Element::setScrollTop): Ditto.
+        * page/EventHandler.cpp:
+        (WebCore::EventHandler::handleWheelEvent): Check for programmatic scroll, and
+        clear latched state if the handler manually scrolled. Clear programmatic
+        scroll state at the end of event handling.
+        (WebCore::EventHandler::clearLatchedState): Refactored code.
+        * page/EventHandler.h:
+        * page/mac/EventHandlerMac.mm:
+        (WebCore::EventHandler::platformPrepareForWheelEvents): Check
+        if scrollable area was scrolled programmatically. If it was, do
+        not honor latching behavior.
+        * platform/ScrollableArea.cpp:
+        (WebCore::ScrollableArea::ScrollableArea): Initialize new member.
+        * platform/ScrollableArea.h:
+        (WebCore::ScrollableArea::isScrolledProgrammatically): Added.
+        (WebCore::ScrollableArea::setScrolledProgrammatically): Added.
+
 2014-04-19  Chris Fleizach  <cfleizach@apple.com>
 

trunk/Source/WebCore/dom/Element.cpp

@@ -62 +62 @@
 #include "PlatformWheelEvent.h"
 #include "PointerLockController.h"
+#include "RenderLayer.h"
 #include "RenderNamedFlowFragment.h"
 #include "RenderRegion.h"
@@ -799 +800 @@
     document().updateLayoutIgnorePendingStylesheets();
 
-    if (RenderBox* rend = renderBox())
-        rend->setScrollLeft(static_cast<int>(newLeft * rend->style().effectiveZoom()));
+    if (RenderBox* renderer = renderBox()) {
+        renderer->setScrollLeft(static_cast<int>(newLeft * renderer->style().effectiveZoom()));
+        if (auto* scrollableArea = renderer->layer())
+            scrollableArea->setScrolledProgrammatically(true);
+    }
 }
 
@@ -807 +811 @@
     document().updateLayoutIgnorePendingStylesheets();
 
-    if (RenderBox* rend = renderBox())
-        rend->setScrollTop(static_cast<int>(newTop * rend->style().effectiveZoom()));
+    if (RenderBox* renderer = renderBox()) {
+        renderer->setScrollTop(static_cast<int>(newTop * renderer->style().effectiveZoom()));
+        if (auto* scrollableArea = renderer->layer())
+            scrollableArea->setScrolledProgrammatically(true);
+    }
 }
 

trunk/Source/WebCore/page/EventHandler.cpp

@@ -2594 +2594 @@
             if (widget && passWheelEventToWidget(e, widget)) {
                 m_isHandlingWheelEvent = false;
+                if (scrollableArea)
+                    scrollableArea->setScrolledProgrammatically(false);
                 return true;
             }
@@ -2600 +2602 @@
         if (!element->dispatchWheelEvent(event)) {
             m_isHandlingWheelEvent = false;
+
+            if (scrollableArea && scrollableArea->isScrolledProgrammatically()) {
+                // Web developer is controlling scrolling. Don't attempt to latch ourselves:
+                clearLatchedState();
+                scrollableArea->setScrolledProgrammatically(false);
+            }
+
             return true;
         }
     }
 
+    if (scrollableArea)
+        scrollableArea->setScrolledProgrammatically(false);
+
     return platformCompleteWheelEvent(e, scrollableContainer, scrollableArea);
+}
+
+void EventHandler::clearLatchedState()
+{
+    m_latchedWheelEventElement = nullptr;
+#if PLATFORM(COCOA)
+    m_latchedScrollableContainer = nullptr;
+#endif
+    m_widgetIsLatched = false;
+    m_previousWheelScrolledElement = nullptr;
 }
 

trunk/Source/WebCore/page/EventHandler.h

@@ -437 +437 @@
 #endif
 
+    void clearLatchedState();
+
     Frame& m_frame;
 

trunk/Source/WebCore/page/mac/EventHandlerMac.mm

@@ -800 +800 @@
         m_recentWheelEventDeltaTracker->beginTrackingDeltas();
     } else if (wheelEvent.shouldResetLatching()) {
-        m_latchedWheelEventElement = nullptr;
-        m_latchedScrollableContainer = nullptr;
-        m_widgetIsLatched = false;
-        m_previousWheelScrolledElement = nullptr;
+        clearLatchedState();
         m_recentWheelEventDeltaTracker->endTrackingDeltas();
     }

trunk/Source/WebCore/platform/ScrollableArea.cpp

@@ -60 +60 @@
     , m_scrollbarOverlayStyle(ScrollbarOverlayStyleDefault)
     , m_scrollOriginChanged(false)
+    , m_scrolledProgrammatically(false)
 {
 }

trunk/Source/WebCore/platform/ScrollableArea.h

@@ -157 +157 @@
     virtual bool scrolledToRight() const;
 
+    bool isScrolledProgrammatically() const { return m_scrolledProgrammatically; }
+    void setScrolledProgrammatically(bool state) { m_scrolledProgrammatically = state; }
+
     enum VisibleContentRectIncludesScrollbars { ExcludeScrollbars, IncludeScrollbars };
     enum VisibleContentRectBehavior {
@@ -293 +296 @@
 
     unsigned m_scrollOriginChanged : 1;
+    unsigned m_scrolledProgrammatically : 1;
 };
 

trunk/WebKit.xcworkspace/xcshareddata/xcschemes/All Source (target WebProcess).xcscheme

@@ -146 +146 @@
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
-      buildConfiguration = "Debug"
+      buildConfiguration = "Release"
       ignoresPersistentStateOnLaunch = "NO"
       debugDocumentVersioning = "YES"