Changeset 55890 in webkit

Timestamp:

Mar 11, 2010 11:07:06 PM (14 years ago)

Author:

eric@webkit.org

Message:

2010-03-11 Benjamin Poulain <​benjamin.poulain@nokia.com>

Reviewed by Adam Treat.

Do not render the full frame when there is some elements with fixed positioning
​https://bugs.webkit.org/show_bug.cgi?id=33150

The frame view take into acount the list of fixed object when scrolling
the view. If the number of object is lower than a certain threshold, the pixel
are blitted, and the invalidated area updated.

• page/FrameView.cpp: (WebCore::FrameView::FrameView): (WebCore::FrameView::useSlowRepaints): (WebCore::FrameView::useSlowRepaintsIfNotOverlapped): (WebCore::FrameView::addFixedObject): (WebCore::FrameView::removeFixedObject): (WebCore::FrameView::scrollContentsFastPath):
• page/FrameView.h:
• platform/ScrollView.cpp: (WebCore::ScrollView::scrollContents): (WebCore::ScrollView::scrollContentsFastPath):
• platform/ScrollView.h:
• rendering/RenderBlock.h: (WebCore::RenderBlock::positionedObjects):
• rendering/RenderBox.cpp: (WebCore::RenderBox::styleWillChange):
• rendering/RenderObject.cpp: (WebCore::RenderObject::styleWillChange):

Location:

trunk/WebCore

Files:

• ChangeLog (modified) (1 diff)
• page/FrameView.cpp (modified) (3 diffs)
• page/FrameView.h (modified) (3 diffs)
• platform/ScrollView.cpp (modified) (2 diffs)
• platform/ScrollView.h (modified) (1 diff)
• rendering/RenderBlock.h (modified) (1 diff)
• rendering/RenderBox.cpp (modified) (1 diff)
• rendering/RenderObject.cpp (modified) (2 diffs)

trunk/WebCore/ChangeLog

@@ +1 @@
+2010-03-11  Benjamin Poulain  <benjamin.poulain@nokia.com>
+
+        Reviewed by Adam Treat.
+
+        Do not render the full frame when there is some elements with fixed positioning
+        https://bugs.webkit.org/show_bug.cgi?id=33150
+
+        The frame view take into acount the list of fixed object when scrolling
+        the view. If the number of object is lower than a certain threshold, the pixel
+        are blitted, and the invalidated area updated.
+
+        * page/FrameView.cpp:
+        (WebCore::FrameView::FrameView):
+        (WebCore::FrameView::useSlowRepaints):
+        (WebCore::FrameView::useSlowRepaintsIfNotOverlapped):
+        (WebCore::FrameView::addFixedObject):
+        (WebCore::FrameView::removeFixedObject):
+        (WebCore::FrameView::scrollContentsFastPath):
+        * page/FrameView.h:
+        * platform/ScrollView.cpp:
+        (WebCore::ScrollView::scrollContents):
+        (WebCore::ScrollView::scrollContentsFastPath):
+        * platform/ScrollView.h:
+        * rendering/RenderBlock.h:
+        (WebCore::RenderBlock::positionedObjects):
+        * rendering/RenderBox.cpp:
+        (WebCore::RenderBox::styleWillChange):
+        * rendering/RenderObject.cpp:
+        (WebCore::RenderObject::styleWillChange):
+
 2010-03-11  Aaron Boodman  <aa@chromium.org>
 

trunk/WebCore/page/FrameView.cpp

@@ -109 +109 @@
     , m_canHaveScrollbars(true)
     , m_slowRepaintObjectCount(0)
+    , m_fixedObjectCount(0)
     , m_layoutTimer(this, &FrameView::layoutTimerFired)
     , m_layoutRoot(0)
@@ -800 +801 @@
 bool FrameView::useSlowRepaints() const
 {
-    return m_useSlowRepaints || m_slowRepaintObjectCount > 0 || m_isOverlapped || !m_contentIsOpaque;
+    return m_useSlowRepaints || m_slowRepaintObjectCount > 0 || (platformWidget() && m_fixedObjectCount > 0) || m_isOverlapped || !m_contentIsOpaque;
 }
 
 bool FrameView::useSlowRepaintsIfNotOverlapped() const
 {
-    return m_useSlowRepaints || m_slowRepaintObjectCount > 0 || !m_contentIsOpaque;
+    return m_useSlowRepaints || m_slowRepaintObjectCount > 0 || (platformWidget() && m_fixedObjectCount > 0) || !m_contentIsOpaque;
 }
 
@@ -827 +828 @@
     if (!m_slowRepaintObjectCount)
         setCanBlitOnScroll(!useSlowRepaints());
+}
+
+void FrameView::addFixedObject()
+{
+    if (!m_fixedObjectCount && platformWidget())
+        setCanBlitOnScroll(false);
+    ++m_fixedObjectCount;
+}
+
+void FrameView::removeFixedObject()
+{
+    ASSERT(m_fixedObjectCount > 0);
+    --m_fixedObjectCount;
+    if (!m_fixedObjectCount)
+        setCanBlitOnScroll(!useSlowRepaints());
+}
+
+bool FrameView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect)
+{
+    const size_t fixedObjectThreshold = 5;
+
+    ListHashSet<RenderBox*>* positionedObjects = 0;
+    if (RenderView* root = m_frame->contentRenderer())
+        positionedObjects = root->positionedObjects();
+
+    if (!positionedObjects || positionedObjects->isEmpty()) {
+        hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
+        return true;
+    }
+
+    // Get the rects of the fixed objects visible in the rectToScroll
+    Vector<IntRect, fixedObjectThreshold> subRectToUpdate;
+    bool updateInvalidatedSubRect = true;
+    ListHashSet<RenderBox*>::const_iterator end = positionedObjects->end();
+    for (ListHashSet<RenderBox*>::const_iterator it = positionedObjects->begin(); it != end; ++it) {
+        RenderBox* renderBox = *it;
+        if (renderBox->style()->position() != FixedPosition)
+            continue;
+        IntRect topLevelRect;
+        IntRect updateRect = renderBox->paintingRootRect(topLevelRect);
+        updateRect.move(-scrollX(), -scrollY());
+        updateRect.intersect(rectToScroll);
+        if (!updateRect.isEmpty()) {
+            if (subRectToUpdate.size() >= fixedObjectThreshold) {
+                updateInvalidatedSubRect = false;
+                break;
+            }
+            subRectToUpdate.append(updateRect);
+        }
+    }
+
+    // Scroll the view
+    if (updateInvalidatedSubRect) {
+        // 1) scroll
+        hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
+
+        // 2) update the area of fixed objects that has been invalidated
+        size_t fixObjectsCount = subRectToUpdate.size();
+        for (size_t i = 0; i < fixObjectsCount; ++i) {
+            IntRect updateRect = subRectToUpdate[i];
+            IntRect scrolledRect = updateRect;
+            scrolledRect.move(scrollDelta);
+            updateRect.unite(scrolledRect);
+            updateRect.intersect(rectToScroll);
+            hostWindow()->invalidateContentsAndWindow(updateRect, false);
+        }
+        return true;
+    }
+
+    // the number of fixed objects exceed the threshold, we cannot use the fast path
+    return false;
 }
 

trunk/WebCore/page/FrameView.h

@@ -150 +150 @@
     void removeSlowRepaintObject();
 
+    void addFixedObject();
+    void removeFixedObject();
+
     void beginDeferredRepaints();
     void endDeferredRepaints();
@@ -203 +206 @@
     bool isFrameViewScrollCorner(RenderScrollbarPart* scrollCorner) const { return m_scrollCorner == scrollCorner; }
     void invalidateScrollCorner();
+
+protected:
+    virtual bool scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect);
 
 private:
@@ -273 +279 @@
     bool m_contentIsOpaque;
     unsigned m_slowRepaintObjectCount;
+    unsigned m_fixedObjectCount;
 
     int m_borderX, m_borderY;

trunk/WebCore/platform/ScrollView.cpp

@@ -511 +511 @@
 
     if (canBlitOnScroll()) { // The main frame can just blit the WebView window
-       // FIXME: Find a way to scroll subframes with this faster path
-       hostWindow()->scroll(-scrollDelta, scrollViewRect, clipRect);
+        // FIXME: Find a way to scroll subframes with this faster path
+        if (!scrollContentsFastPath(-scrollDelta, scrollViewRect, clipRect))
+            hostWindow()->invalidateContentsForSlowScroll(updateRect, false);
     } else { 
        // We need to go ahead and repaint the entire backing store.  Do it now before moving the
@@ -524 +525 @@
     // Now blit the backingstore into the window which should be very fast.
     hostWindow()->invalidateWindow(IntRect(), true);
+}
+
+bool ScrollView::scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect)
+{
+    hostWindow()->scroll(scrollDelta, rectToScroll, clipRect);
+    return true;
 }
 

trunk/WebCore/platform/ScrollView.h

@@ -250 +250 @@
     virtual void updateScrollCorner();
     virtual void paintScrollCorner(GraphicsContext*, const IntRect& cornerRect);
+
+    // Scroll the content by blitting the pixels
+    virtual bool scrollContentsFastPath(const IntSize& scrollDelta, const IntRect& rectToScroll, const IntRect& clipRect);
     
 private:

trunk/WebCore/rendering/RenderBlock.h

@@ -75 +75 @@
     void removePositionedObject(RenderBox*);
     void removePositionedObjects(RenderBlock*);
+    ListHashSet<RenderBox*>* positionedObjects() const { return m_positionedObjects; }
 
     void addPercentHeightDescendant(RenderBox*);

trunk/WebCore/rendering/RenderBox.cpp

@@ -145 +145 @@
             if (isFloating() && !isPositioned() && (newStyle->position() == AbsolutePosition || newStyle->position() == FixedPosition))
                 removeFloatingOrPositionedChildFromBlockLists();
+        }
+    }
+    if (FrameView *frameView = view()->frameView()) {
+        bool newStyleIsFixed = newStyle && newStyle->position() == FixedPosition;
+        bool oldStyleIsFixed = style() && style()->position() == FixedPosition;
+        if (newStyleIsFixed != oldStyleIsFixed) {
+            if (newStyleIsFixed)
+                frameView->addFixedObject();
+            else
+                frameView->removeFixedObject();
         }
     }

trunk/WebCore/rendering/RenderObject.cpp

@@ -1653 +1653 @@
 
     if (view()->frameView()) {
-        // FIXME: A better solution would be to only invalidate the fixed regions when scrolling.  It's overkill to
-        // prevent the entire view from blitting on a scroll.
-
         bool shouldBlitOnFixedBackgroundImage = false;
 #if ENABLE(FAST_MOBILE_SCROLLING)
@@ -1665 +1662 @@
 #endif
 
-        bool newStyleSlowScroll = newStyle && (newStyle->position() == FixedPosition
-                                               || (!shouldBlitOnFixedBackgroundImage && newStyle->hasFixedBackgroundImage()));
-        bool oldStyleSlowScroll = m_style && (m_style->position() == FixedPosition
-                                               || (!shouldBlitOnFixedBackgroundImage && m_style->hasFixedBackgroundImage()));
+        bool newStyleSlowScroll = newStyle && !shouldBlitOnFixedBackgroundImage && newStyle->hasFixedBackgroundImage();
+        bool oldStyleSlowScroll = m_style && !shouldBlitOnFixedBackgroundImage && m_style->hasFixedBackgroundImage();
         if (oldStyleSlowScroll != newStyleSlowScroll) {
             if (oldStyleSlowScroll)