Home | History | Annotate | Download | only in rendering
      1 /*
      2  * Copyright (C) 2003, 2009 Apple Inc. All rights reserved.
      3  *
      4  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
      5  *
      6  * Other contributors:
      7  *   Robert O'Callahan <roc+@cs.cmu.edu>
      8  *   David Baron <dbaron (at) fas.harvard.edu>
      9  *   Christian Biesinger <cbiesinger (at) web.de>
     10  *   Randall Jesup <rjesup (at) wgate.com>
     11  *   Roland Mainz <roland.mainz (at) informatik.med.uni-giessen.de>
     12  *   Josh Soref <timeless (at) mac.com>
     13  *   Boris Zbarsky <bzbarsky (at) mit.edu>
     14  *
     15  * This library is free software; you can redistribute it and/or
     16  * modify it under the terms of the GNU Lesser General Public
     17  * License as published by the Free Software Foundation; either
     18  * version 2.1 of the License, or (at your option) any later version.
     19  *
     20  * This library is distributed in the hope that it will be useful,
     21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     23  * Lesser General Public License for more details.
     24  *
     25  * You should have received a copy of the GNU Lesser General Public
     26  * License along with this library; if not, write to the Free Software
     27  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     28  *
     29  * Alternatively, the contents of this file may be used under the terms
     30  * of either the Mozilla Public License Version 1.1, found at
     31  * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
     32  * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
     33  * (the "GPL"), in which case the provisions of the MPL or the GPL are
     34  * applicable instead of those above.  If you wish to allow use of your
     35  * version of this file only under the terms of one of those two
     36  * licenses (the MPL or the GPL) and not to allow others to use your
     37  * version of this file under the LGPL, indicate your decision by
     38  * deletingthe provisions above and replace them with the notice and
     39  * other provisions required by the MPL or the GPL, as the case may be.
     40  * If you do not delete the provisions above, a recipient may use your
     41  * version of this file under any of the LGPL, the MPL or the GPL.
     42  */
     43 
     44 #ifndef RenderLayer_h
     45 #define RenderLayer_h
     46 
     47 #include "PaintInfo.h"
     48 #include "RenderBox.h"
     49 #include "ScrollBehavior.h"
     50 #include "ScrollableArea.h"
     51 #include <wtf/OwnPtr.h>
     52 
     53 namespace WebCore {
     54 
     55 class HitTestRequest;
     56 class HitTestResult;
     57 class HitTestingTransformState;
     58 class RenderMarquee;
     59 class RenderReplica;
     60 class RenderScrollbarPart;
     61 class RenderStyle;
     62 class RenderView;
     63 class Scrollbar;
     64 class TransformationMatrix;
     65 
     66 #if USE(ACCELERATED_COMPOSITING)
     67 class RenderLayerBacking;
     68 class RenderLayerCompositor;
     69 #endif
     70 
     71 class ClipRects {
     72 public:
     73     ClipRects()
     74         : m_refCnt(0)
     75         , m_fixed(false)
     76     {
     77     }
     78 
     79     ClipRects(const IntRect& r)
     80         : m_overflowClipRect(r)
     81         , m_fixedClipRect(r)
     82         , m_posClipRect(r)
     83         , m_refCnt(0)
     84         , m_fixed(false)
     85     {
     86     }
     87 
     88     ClipRects(const ClipRects& other)
     89         : m_overflowClipRect(other.overflowClipRect())
     90         , m_fixedClipRect(other.fixedClipRect())
     91         , m_posClipRect(other.posClipRect())
     92         , m_refCnt(0)
     93         , m_fixed(other.fixed())
     94     {
     95     }
     96 
     97     void reset(const IntRect& r)
     98     {
     99         m_overflowClipRect = r;
    100         m_fixedClipRect = r;
    101         m_posClipRect = r;
    102         m_fixed = false;
    103     }
    104 
    105     const IntRect& overflowClipRect() const { return m_overflowClipRect; }
    106     void setOverflowClipRect(const IntRect& r) { m_overflowClipRect = r; }
    107 
    108     const IntRect& fixedClipRect() const { return m_fixedClipRect; }
    109     void setFixedClipRect(const IntRect&r) { m_fixedClipRect = r; }
    110 
    111     const IntRect& posClipRect() const { return m_posClipRect; }
    112     void setPosClipRect(const IntRect& r) { m_posClipRect = r; }
    113 
    114     bool fixed() const { return m_fixed; }
    115     void setFixed(bool fixed) { m_fixed = fixed; }
    116 
    117     void ref() { m_refCnt++; }
    118     void deref(RenderArena* renderArena) { if (--m_refCnt == 0) destroy(renderArena); }
    119 
    120     void destroy(RenderArena*);
    121 
    122     // Overloaded new operator.
    123     void* operator new(size_t, RenderArena*) throw();
    124 
    125     // Overridden to prevent the normal delete from being called.
    126     void operator delete(void*, size_t);
    127 
    128     bool operator==(const ClipRects& other) const
    129     {
    130         return m_overflowClipRect == other.overflowClipRect() &&
    131                m_fixedClipRect == other.fixedClipRect() &&
    132                m_posClipRect == other.posClipRect() &&
    133                m_fixed == other.fixed();
    134     }
    135 
    136     ClipRects& operator=(const ClipRects& other)
    137     {
    138         m_overflowClipRect = other.overflowClipRect();
    139         m_fixedClipRect = other.fixedClipRect();
    140         m_posClipRect = other.posClipRect();
    141         m_fixed = other.fixed();
    142         return *this;
    143     }
    144 
    145 private:
    146     // The normal operator new is disallowed on all render objects.
    147     void* operator new(size_t) throw();
    148 
    149 private:
    150     IntRect m_overflowClipRect;
    151     IntRect m_fixedClipRect;
    152     IntRect m_posClipRect;
    153     unsigned m_refCnt : 31;
    154     bool m_fixed : 1;
    155 };
    156 
    157 class RenderLayer : public ScrollableArea {
    158 public:
    159     friend class RenderReplica;
    160 
    161     RenderLayer(RenderBoxModelObject*);
    162     ~RenderLayer();
    163 
    164     RenderBoxModelObject* renderer() const { return m_renderer; }
    165     RenderBox* renderBox() const { return m_renderer && m_renderer->isBox() ? toRenderBox(m_renderer) : 0; }
    166     RenderLayer* parent() const { return m_parent; }
    167     RenderLayer* previousSibling() const { return m_previous; }
    168     RenderLayer* nextSibling() const { return m_next; }
    169     RenderLayer* firstChild() const { return m_first; }
    170     RenderLayer* lastChild() const { return m_last; }
    171 
    172     void addChild(RenderLayer* newChild, RenderLayer* beforeChild = 0);
    173     RenderLayer* removeChild(RenderLayer*);
    174 
    175     void removeOnlyThisLayer();
    176     void insertOnlyThisLayer();
    177 
    178     void repaintIncludingDescendants();
    179 
    180 #if USE(ACCELERATED_COMPOSITING)
    181     // Indicate that the layer contents need to be repainted. Only has an effect
    182     // if layer compositing is being used,
    183     void setBackingNeedsRepaint();
    184     void setBackingNeedsRepaintInRect(const IntRect& r); // r is in the coordinate space of the layer's render object
    185     void repaintIncludingNonCompositingDescendants(RenderBoxModelObject* repaintContainer);
    186 #endif
    187 
    188     void styleChanged(StyleDifference, const RenderStyle* oldStyle);
    189 
    190     RenderMarquee* marquee() const { return m_marquee; }
    191 
    192     bool isNormalFlowOnly() const { return m_isNormalFlowOnly; }
    193     bool isSelfPaintingLayer() const;
    194 
    195     bool requiresSlowRepaints() const;
    196 
    197     bool isTransparent() const;
    198     RenderLayer* transparentPaintingAncestor();
    199     void beginTransparencyLayers(GraphicsContext*, const RenderLayer* rootLayer, PaintBehavior);
    200 
    201     bool hasReflection() const { return renderer()->hasReflection(); }
    202     bool isReflection() const { return renderer()->isReplica(); }
    203     RenderReplica* reflection() const { return m_reflection; }
    204     RenderLayer* reflectionLayer() const;
    205 
    206     const RenderLayer* root() const
    207     {
    208         const RenderLayer* curr = this;
    209         while (curr->parent())
    210             curr = curr->parent();
    211         return curr;
    212     }
    213 
    214     int x() const { return m_x; }
    215     int y() const { return m_y; }
    216     void setLocation(int x, int y)
    217     {
    218         m_x = x;
    219         m_y = y;
    220     }
    221 
    222     int width() const { return m_width; }
    223     int height() const { return m_height; }
    224     IntSize size() const { return IntSize(m_width, m_height); }
    225 
    226 #if PLATFORM(ANDROID)
    227     void setWidth(int w);
    228     void setHeight(int h);
    229 #else
    230     void setWidth(int w) { m_width = w; }
    231     void setHeight(int h) { m_height = h; }
    232 #endif
    233 
    234     int scrollWidth();
    235     int scrollHeight();
    236 
    237     void panScrollFromPoint(const IntPoint&);
    238 
    239     // Scrolling methods for layers that can scroll their overflow.
    240     void scrollByRecursively(int xDelta, int yDelta);
    241 
    242     IntSize scrolledContentOffset() const { return IntSize(scrollXOffset() + m_scrollLeftOverflow, scrollYOffset() + m_scrollTopOverflow); }
    243 
    244     int scrollXOffset() const { return m_scrollX + m_scrollOrigin.x(); }
    245     int scrollYOffset() const { return m_scrollY + m_scrollOrigin.y(); }
    246 
    247     void scrollToOffset(int x, int y);
    248     void scrollToXOffset(int x) { scrollToOffset(x, m_scrollY + m_scrollOrigin.y()); }
    249     void scrollToYOffset(int y) { scrollToOffset(m_scrollX + m_scrollOrigin.x(), y); }
    250     void scrollRectToVisible(const IntRect&, bool scrollToAnchor = false, const ScrollAlignment& alignX = ScrollAlignment::alignCenterIfNeeded, const ScrollAlignment& alignY = ScrollAlignment::alignCenterIfNeeded);
    251 
    252     IntRect getRectToExpose(const IntRect& visibleRect, const IntRect& exposeRect, const ScrollAlignment& alignX, const ScrollAlignment& alignY);
    253 
    254     void setHasHorizontalScrollbar(bool);
    255     void setHasVerticalScrollbar(bool);
    256 
    257     PassRefPtr<Scrollbar> createScrollbar(ScrollbarOrientation);
    258     void destroyScrollbar(ScrollbarOrientation);
    259 
    260     // ScrollableArea overrides
    261     virtual Scrollbar* horizontalScrollbar() const { return m_hBar.get(); }
    262     virtual Scrollbar* verticalScrollbar() const { return m_vBar.get(); }
    263 
    264     int verticalScrollbarWidth(OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
    265     int horizontalScrollbarHeight(OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
    266 
    267     bool hasOverflowControls() const;
    268     bool isPointInResizeControl(const IntPoint& absolutePoint) const;
    269     bool hitTestOverflowControls(HitTestResult&, const IntPoint& localPoint);
    270     IntSize offsetFromResizeCorner(const IntPoint& absolutePoint) const;
    271 
    272     void paintOverflowControls(GraphicsContext*, int tx, int ty, const IntRect& damageRect, bool paintingOverlayControls = false);
    273     void paintScrollCorner(GraphicsContext*, int tx, int ty, const IntRect& damageRect);
    274     void paintResizer(GraphicsContext*, int tx, int ty, const IntRect& damageRect);
    275 
    276     void updateScrollInfoAfterLayout();
    277 
    278     bool scroll(ScrollDirection, ScrollGranularity, float multiplier = 1);
    279     void autoscroll();
    280 
    281     void resize(const PlatformMouseEvent&, const IntSize&);
    282     bool inResizeMode() const { return m_inResizeMode; }
    283     void setInResizeMode(bool b) { m_inResizeMode = b; }
    284 
    285     bool isRootLayer() const { return renderer()->isRenderView(); }
    286 
    287 #if USE(ACCELERATED_COMPOSITING)
    288     RenderLayerCompositor* compositor() const;
    289 
    290     // Notification from the renderer that its content changed (e.g. current frame of image changed).
    291     // Allows updates of layer content without repainting.
    292     enum ContentChangeType { ImageChanged, MaskImageChanged, CanvasChanged, VideoChanged, FullScreenChanged };
    293     void contentChanged(ContentChangeType);
    294 #endif
    295 
    296     // Returns true if the accelerated compositing is enabled
    297     bool hasAcceleratedCompositing() const;
    298 
    299     bool canRender3DTransforms() const;
    300 
    301     void updateLayerPosition();
    302 
    303     enum UpdateLayerPositionsFlag {
    304         CheckForRepaint = 1,
    305         IsCompositingUpdateRoot = 1 << 1,
    306         UpdateCompositingLayers = 1 << 2,
    307         UpdatePagination = 1 << 3
    308     };
    309     typedef unsigned UpdateLayerPositionsFlags;
    310     void updateLayerPositions(UpdateLayerPositionsFlags = CheckForRepaint | IsCompositingUpdateRoot | UpdateCompositingLayers, IntPoint* cachedOffset = 0);
    311 
    312     void updateTransform();
    313 
    314     void relativePositionOffset(int& relX, int& relY) const { relX += m_relX; relY += m_relY; }
    315     IntSize relativePositionOffset() const { return IntSize(m_relX, m_relY); }
    316 
    317     void clearClipRectsIncludingDescendants();
    318     void clearClipRects();
    319 
    320     void addBlockSelectionGapsBounds(const IntRect&);
    321     void clearBlockSelectionGapsBounds();
    322     void repaintBlockSelectionGaps();
    323 
    324     // Get the enclosing stacking context for this layer.  A stacking context is a layer
    325     // that has a non-auto z-index.
    326     RenderLayer* stackingContext() const;
    327 #if ENABLE(COMPOSITED_FIXED_ELEMENTS)
    328     bool isFixed() const { return renderer()->isPositioned() && renderer()->style()->position() == FixedPosition; }
    329     // If fixed elements are composited, they will be containing children
    330     bool isStackingContext() const {
    331 #if ENABLE(ANDROID_OVERFLOW_SCROLL)
    332       if (hasOverflowScroll())
    333           return true;
    334 #endif
    335       return !hasAutoZIndex() || renderer()->isRenderView() || (isComposited() && isFixed());
    336     }
    337 #else
    338 #if ENABLE(ANDROID_OVERFLOW_SCROLL)
    339     bool isStackingContext() const { return !hasAutoZIndex() || renderer()->isRenderView() || hasOverflowScroll(); }
    340 #else
    341     bool isStackingContext() const { return !hasAutoZIndex() || renderer()->isRenderView() ; }
    342 #endif
    343 #endif
    344 
    345     void dirtyZOrderLists();
    346     void dirtyStackingContextZOrderLists();
    347     void updateZOrderLists();
    348     Vector<RenderLayer*>* posZOrderList() const { return m_posZOrderList; }
    349     Vector<RenderLayer*>* negZOrderList() const { return m_negZOrderList; }
    350 
    351     void dirtyNormalFlowList();
    352     void updateNormalFlowList();
    353     Vector<RenderLayer*>* normalFlowList() const { return m_normalFlowList; }
    354 
    355     bool hasVisibleContent() const { return m_hasVisibleContent; }
    356     bool hasVisibleDescendant() const { return m_hasVisibleDescendant; }
    357     void setHasVisibleContent(bool);
    358     void dirtyVisibleContentStatus();
    359 
    360     // Gets the nearest enclosing positioned ancestor layer (also includes
    361     // the <html> layer and the root layer).
    362     RenderLayer* enclosingPositionedAncestor() const;
    363 
    364     // The layer relative to which clipping rects for this layer are computed.
    365     RenderLayer* clippingRoot() const;
    366 
    367 #if USE(ACCELERATED_COMPOSITING)
    368     // Enclosing compositing layer; if includeSelf is true, may return this.
    369     RenderLayer* enclosingCompositingLayer(bool includeSelf = true) const;
    370     // Ancestor compositing layer, excluding this.
    371     RenderLayer* ancestorCompositingLayer() const { return enclosingCompositingLayer(false); }
    372 #endif
    373 
    374     void convertToLayerCoords(const RenderLayer* ancestorLayer, int& x, int& y) const;
    375 
    376     bool hasAutoZIndex() const { return renderer()->style()->hasAutoZIndex(); }
    377     int zIndex() const { return renderer()->style()->zIndex(); }
    378 
    379     // The two main functions that use the layer system.  The paint method
    380     // paints the layers that intersect the damage rect from back to
    381     // front.  The hitTest method looks for mouse events by walking
    382     // layers that intersect the point from front to back.
    383     void paint(GraphicsContext*, const IntRect& damageRect, PaintBehavior = PaintBehaviorNormal, RenderObject* paintingRoot = 0);
    384     bool hitTest(const HitTestRequest&, HitTestResult&);
    385     void paintOverlayScrollbars(GraphicsContext*, const IntRect& damageRect, PaintBehavior, RenderObject* paintingRoot);
    386 
    387     // This method figures out our layerBounds in coordinates relative to
    388     // |rootLayer}.  It also computes our background and foreground clip rects
    389     // for painting/event handling.
    390     void calculateRects(const RenderLayer* rootLayer, const IntRect& paintDirtyRect, IntRect& layerBounds,
    391                         IntRect& backgroundRect, IntRect& foregroundRect, IntRect& outlineRect, bool temporaryClipRects = false,
    392                         OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
    393 
    394     // Compute and cache clip rects computed with the given layer as the root
    395     void updateClipRects(const RenderLayer* rootLayer, OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize);
    396     // Compute and return the clip rects. If useCached is true, will used previously computed clip rects on ancestors
    397     // (rather than computing them all from scratch up the parent chain).
    398     void calculateClipRects(const RenderLayer* rootLayer, ClipRects&, bool useCached = false, OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
    399     ClipRects* clipRects() const { return m_clipRects; }
    400 
    401     IntRect childrenClipRect() const; // Returns the foreground clip rect of the layer in the document's coordinate space.
    402     IntRect selfClipRect() const; // Returns the background clip rect of the layer in the document's coordinate space.
    403 
    404     bool intersectsDamageRect(const IntRect& layerBounds, const IntRect& damageRect, const RenderLayer* rootLayer) const;
    405 
    406     // Bounding box relative to some ancestor layer.
    407     IntRect boundingBox(const RenderLayer* rootLayer) const;
    408     // Bounding box in the coordinates of this layer.
    409     IntRect localBoundingBox() const;
    410     // Bounding box relative to the root.
    411     IntRect absoluteBoundingBox() const;
    412 
    413     void updateHoverActiveState(const HitTestRequest&, HitTestResult&);
    414 
    415     // Return a cached repaint rect, computed relative to the layer renderer's containerForRepaint.
    416     IntRect repaintRect() const { return m_repaintRect; }
    417     IntRect repaintRectIncludingDescendants() const;
    418     void computeRepaintRects();
    419     void updateRepaintRectsAfterScroll(bool fixed = false);
    420     void setNeedsFullRepaint(bool f = true) { m_needsFullRepaint = f; }
    421 
    422     int staticInlinePosition() const { return m_staticInlinePosition; }
    423     int staticBlockPosition() const { return m_staticBlockPosition; }
    424     void setStaticInlinePosition(int position) { m_staticInlinePosition = position; }
    425     void setStaticBlockPosition(int position) { m_staticBlockPosition = position; }
    426 
    427     bool hasTransform() const { return renderer()->hasTransform(); }
    428     // Note that this transform has the transform-origin baked in.
    429     TransformationMatrix* transform() const { return m_transform.get(); }
    430     // currentTransform computes a transform which takes accelerated animations into account. The
    431     // resulting transform has transform-origin baked in. If the layer does not have a transform,
    432     // returns the identity matrix.
    433     TransformationMatrix currentTransform() const;
    434     TransformationMatrix renderableTransform(PaintBehavior) const;
    435 
    436     // Get the perspective transform, which is applied to transformed sublayers.
    437     // Returns true if the layer has a -webkit-perspective.
    438     // Note that this transform has the perspective-origin baked in.
    439     TransformationMatrix perspectiveTransform() const;
    440     FloatPoint perspectiveOrigin() const;
    441     bool preserves3D() const { return renderer()->style()->transformStyle3D() == TransformStyle3DPreserve3D; }
    442     bool has3DTransform() const { return m_transform && !m_transform->isAffine(); }
    443 
    444      // Overloaded new operator.  Derived classes must override operator new
    445     // in order to allocate out of the RenderArena.
    446     void* operator new(size_t, RenderArena*) throw();
    447 
    448     // Overridden to prevent the normal delete from being called.
    449     void operator delete(void*, size_t);
    450 
    451 #if USE(ACCELERATED_COMPOSITING)
    452     bool isComposited() const { return m_backing != 0; }
    453     bool hasCompositedMask() const;
    454     RenderLayerBacking* backing() const { return m_backing.get(); }
    455     RenderLayerBacking* ensureBacking();
    456     void clearBacking();
    457     virtual GraphicsLayer* layerForHorizontalScrollbar() const;
    458     virtual GraphicsLayer* layerForVerticalScrollbar() const;
    459     virtual GraphicsLayer* layerForScrollCorner() const;
    460 #else
    461     bool isComposited() const { return false; }
    462     bool hasCompositedMask() const { return false; }
    463 #endif
    464 
    465     bool paintsWithTransparency(PaintBehavior paintBehavior) const
    466     {
    467         return isTransparent() && ((paintBehavior & PaintBehaviorFlattenCompositingLayers) || !isComposited());
    468     }
    469 
    470     bool paintsWithTransform(PaintBehavior) const;
    471 
    472     bool containsDirtyOverlayScrollbars() const { return m_containsDirtyOverlayScrollbars; }
    473     void setContainsDirtyOverlayScrollbars(bool dirtyScrollbars) { m_containsDirtyOverlayScrollbars = dirtyScrollbars; }
    474 
    475 #if ENABLE(ANDROID_OVERFLOW_SCROLL)
    476     bool hasOverflowScroll() const { return m_hasOverflowScroll; }
    477     bool hasOverflowParent() const;
    478 #endif
    479 #if PLATFORM(ANDROID)
    480     bool intrinsicallyComposited() const { return m_intrinsicallyComposited; }
    481     void setIntrinsicallyComposited(bool intrinsicallyComposited) {
    482         m_intrinsicallyComposited = intrinsicallyComposited;
    483     }
    484 #endif
    485 
    486 private:
    487     // The normal operator new is disallowed on all render objects.
    488     void* operator new(size_t) throw();
    489 
    490     void setNextSibling(RenderLayer* next) { m_next = next; }
    491     void setPreviousSibling(RenderLayer* prev) { m_previous = prev; }
    492     void setParent(RenderLayer* parent);
    493     void setFirstChild(RenderLayer* first) { m_first = first; }
    494     void setLastChild(RenderLayer* last) { m_last = last; }
    495 
    496     int renderBoxX() const { return renderer()->isBox() ? toRenderBox(renderer())->x() : 0; }
    497     int renderBoxY() const { return renderer()->isBox() ? toRenderBox(renderer())->y() : 0; }
    498 
    499     void collectLayers(Vector<RenderLayer*>*&, Vector<RenderLayer*>*&);
    500 
    501     void updateLayerListsIfNeeded();
    502     void updateCompositingAndLayerListsIfNeeded();
    503 
    504     enum PaintLayerFlag {
    505         PaintLayerHaveTransparency = 1,
    506         PaintLayerAppliedTransform = 1 << 1,
    507         PaintLayerTemporaryClipRects = 1 << 2,
    508         PaintLayerPaintingReflection = 1 << 3,
    509         PaintLayerPaintingOverlayScrollbars = 1 << 4
    510     };
    511 
    512     typedef unsigned PaintLayerFlags;
    513 
    514     void paintLayer(RenderLayer* rootLayer, GraphicsContext*, const IntRect& paintDirtyRect,
    515                     PaintBehavior, RenderObject* paintingRoot, OverlapTestRequestMap* = 0,
    516                     PaintLayerFlags = 0);
    517     void paintList(Vector<RenderLayer*>*, RenderLayer* rootLayer, GraphicsContext* p,
    518                    const IntRect& paintDirtyRect, PaintBehavior,
    519                    RenderObject* paintingRoot, OverlapTestRequestMap*,
    520                    PaintLayerFlags);
    521     void paintPaginatedChildLayer(RenderLayer* childLayer, RenderLayer* rootLayer, GraphicsContext*,
    522                                   const IntRect& paintDirtyRect, PaintBehavior,
    523                                   RenderObject* paintingRoot, OverlapTestRequestMap*,
    524                                   PaintLayerFlags);
    525     void paintChildLayerIntoColumns(RenderLayer* childLayer, RenderLayer* rootLayer, GraphicsContext*,
    526                                     const IntRect& paintDirtyRect, PaintBehavior,
    527                                     RenderObject* paintingRoot, OverlapTestRequestMap*,
    528                                     PaintLayerFlags, const Vector<RenderLayer*>& columnLayers, size_t columnIndex);
    529 
    530     RenderLayer* hitTestLayer(RenderLayer* rootLayer, RenderLayer* containerLayer, const HitTestRequest& request, HitTestResult& result,
    531                               const IntRect& hitTestRect, const IntPoint& hitTestPoint, bool appliedTransform,
    532                               const HitTestingTransformState* transformState = 0, double* zOffset = 0);
    533     RenderLayer* hitTestList(Vector<RenderLayer*>*, RenderLayer* rootLayer, const HitTestRequest& request, HitTestResult& result,
    534                              const IntRect& hitTestRect, const IntPoint& hitTestPoint,
    535                              const HitTestingTransformState* transformState, double* zOffsetForDescendants, double* zOffset,
    536                              const HitTestingTransformState* unflattenedTransformState, bool depthSortDescendants);
    537     RenderLayer* hitTestPaginatedChildLayer(RenderLayer* childLayer, RenderLayer* rootLayer, const HitTestRequest& request, HitTestResult& result,
    538                                             const IntRect& hitTestRect, const IntPoint& hitTestPoint,
    539                                             const HitTestingTransformState* transformState, double* zOffset);
    540     RenderLayer* hitTestChildLayerColumns(RenderLayer* childLayer, RenderLayer* rootLayer, const HitTestRequest& request, HitTestResult& result,
    541                                           const IntRect& hitTestRect, const IntPoint& hitTestPoint,
    542                                           const HitTestingTransformState* transformState, double* zOffset,
    543                                           const Vector<RenderLayer*>& columnLayers, size_t columnIndex);
    544 
    545     PassRefPtr<HitTestingTransformState> createLocalTransformState(RenderLayer* rootLayer, RenderLayer* containerLayer,
    546                             const IntRect& hitTestRect, const IntPoint& hitTestPoint,
    547                             const HitTestingTransformState* containerTransformState) const;
    548 
    549     bool hitTestContents(const HitTestRequest&, HitTestResult&, const IntRect& layerBounds, const IntPoint& hitTestPoint, HitTestFilter) const;
    550 
    551     void computeScrollDimensions(bool* needHBar = 0, bool* needVBar = 0);
    552 
    553     bool shouldBeNormalFlowOnly() const;
    554 
    555     // ScrollableArea interface
    556     virtual int scrollSize(ScrollbarOrientation orientation) const;
    557     virtual void setScrollOffset(const IntPoint&);
    558     virtual int scrollPosition(Scrollbar*) const;
    559     virtual void invalidateScrollbarRect(Scrollbar*, const IntRect&);
    560     virtual void invalidateScrollCornerRect(const IntRect&);
    561     virtual bool isActive() const;
    562     virtual bool isScrollCornerVisible() const;
    563     virtual IntRect scrollCornerRect() const;
    564     virtual IntRect convertFromScrollbarToContainingView(const Scrollbar*, const IntRect&) const;
    565     virtual IntRect convertFromContainingViewToScrollbar(const Scrollbar*, const IntRect&) const;
    566     virtual IntPoint convertFromScrollbarToContainingView(const Scrollbar*, const IntPoint&) const;
    567     virtual IntPoint convertFromContainingViewToScrollbar(const Scrollbar*, const IntPoint&) const;
    568     virtual IntSize contentsSize() const;
    569     virtual int visibleHeight() const;
    570     virtual int visibleWidth() const;
    571     virtual IntPoint currentMousePosition() const;
    572     virtual bool shouldSuspendScrollAnimations() const;
    573 
    574     // Rectangle encompassing the scroll corner and resizer rect.
    575     IntRect scrollCornerAndResizerRect() const;
    576 
    577     virtual void disconnectFromPage() { m_page = 0; }
    578 
    579     // NOTE: This should only be called by the overriden setScrollOffset from ScrollableArea.
    580     void scrollTo(int x, int y);
    581 
    582     IntSize scrollbarOffset(const Scrollbar*) const;
    583 
    584     void updateOverflowStatus(bool horizontalOverflow, bool verticalOverflow);
    585 
    586     void childVisibilityChanged(bool newVisibility);
    587     void dirtyVisibleDescendantStatus();
    588     void updateVisibilityStatus();
    589 
    590     // This flag is computed by RenderLayerCompositor, which knows more about 3d hierarchies than we do.
    591     void setHas3DTransformedDescendant(bool b) { m_has3DTransformedDescendant = b; }
    592     bool has3DTransformedDescendant() const { return m_has3DTransformedDescendant; }
    593 
    594     void dirty3DTransformedDescendantStatus();
    595     // Both updates the status, and returns true if descendants of this have 3d.
    596     bool update3DTransformedDescendantStatus();
    597 
    598     Node* enclosingElement() const;
    599 
    600     void createReflection();
    601     void removeReflection();
    602 
    603     void updateReflectionStyle();
    604     bool paintingInsideReflection() const { return m_paintingInsideReflection; }
    605     void setPaintingInsideReflection(bool b) { m_paintingInsideReflection = b; }
    606 
    607     void parentClipRects(const RenderLayer* rootLayer, ClipRects&, bool temporaryClipRects = false, OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
    608     IntRect backgroundClipRect(const RenderLayer* rootLayer, bool temporaryClipRects, OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
    609 
    610     RenderLayer* enclosingTransformedAncestor() const;
    611 
    612     // Convert a point in absolute coords into layer coords, taking transforms into account
    613     IntPoint absoluteToContents(const IntPoint&) const;
    614 
    615     void positionOverflowControls(int tx, int ty);
    616     void updateScrollCornerStyle();
    617     void updateResizerStyle();
    618 
    619     void updatePagination();
    620     bool isPaginated() const { return m_isPaginated; }
    621 
    622 #if USE(ACCELERATED_COMPOSITING)
    623     bool hasCompositingDescendant() const { return m_hasCompositingDescendant; }
    624     void setHasCompositingDescendant(bool b)  { m_hasCompositingDescendant = b; }
    625 
    626     bool mustOverlapCompositedLayers() const { return m_mustOverlapCompositedLayers; }
    627     void setMustOverlapCompositedLayers(bool b) { m_mustOverlapCompositedLayers = b; }
    628 #if ENABLE(COMPOSITED_FIXED_ELEMENTS)
    629     bool shouldComposite() { return m_shouldComposite; }
    630     void setShouldComposite(bool b) { m_shouldComposite = b; }
    631 #endif
    632 #endif
    633 
    634     void updateContentsScale(float);
    635 
    636     friend class RenderLayerBacking;
    637     friend class RenderLayerCompositor;
    638     friend class RenderBoxModelObject;
    639 
    640     // Only safe to call from RenderBoxModelObject::destroyLayer(RenderArena*)
    641     void destroy(RenderArena*);
    642 
    643     int overflowTop() const;
    644     int overflowBottom() const;
    645     int overflowLeft() const;
    646     int overflowRight() const;
    647 
    648 protected:
    649     RenderBoxModelObject* m_renderer;
    650 
    651     RenderLayer* m_parent;
    652     RenderLayer* m_previous;
    653     RenderLayer* m_next;
    654     RenderLayer* m_first;
    655     RenderLayer* m_last;
    656 
    657     IntRect m_repaintRect; // Cached repaint rects. Used by layout.
    658     IntRect m_outlineBox;
    659 
    660     // Our current relative position offset.
    661     int m_relX;
    662     int m_relY;
    663 
    664     // Our (x,y) coordinates are in our parent layer's coordinate space.
    665     int m_x;
    666     int m_y;
    667 
    668     // The layer's width/height
    669     int m_width;
    670     int m_height;
    671 
    672     // Our scroll offsets if the view is scrolled.
    673     int m_scrollX;
    674     int m_scrollY;
    675 
    676     int m_scrollLeftOverflow;
    677     int m_scrollTopOverflow;
    678 
    679     // The width/height of our scrolled area.
    680     int m_scrollWidth;
    681     int m_scrollHeight;
    682 
    683     // For layers with overflow, we have a pair of scrollbars.
    684     RefPtr<Scrollbar> m_hBar;
    685     RefPtr<Scrollbar> m_vBar;
    686 
    687     // Keeps track of whether the layer is currently resizing, so events can cause resizing to start and stop.
    688     bool m_inResizeMode;
    689 
    690     // For layers that establish stacking contexts, m_posZOrderList holds a sorted list of all the
    691     // descendant layers within the stacking context that have z-indices of 0 or greater
    692     // (auto will count as 0).  m_negZOrderList holds descendants within our stacking context with negative
    693     // z-indices.
    694     Vector<RenderLayer*>* m_posZOrderList;
    695     Vector<RenderLayer*>* m_negZOrderList;
    696 
    697     // This list contains child layers that cannot create stacking contexts.  For now it is just
    698     // overflow layers, but that may change in the future.
    699     Vector<RenderLayer*>* m_normalFlowList;
    700 
    701     ClipRects* m_clipRects;      // Cached clip rects used when painting and hit testing.
    702 #ifndef NDEBUG
    703     const RenderLayer* m_clipRectsRoot;   // Root layer used to compute clip rects.
    704 #endif
    705 
    706     bool m_scrollDimensionsDirty : 1;
    707     bool m_zOrderListsDirty : 1;
    708     bool m_normalFlowListDirty: 1;
    709     bool m_isNormalFlowOnly : 1;
    710 
    711     bool m_usedTransparency : 1; // Tracks whether we need to close a transparent layer, i.e., whether
    712                                  // we ended up painting this layer or any descendants (and therefore need to
    713                                  // blend).
    714     bool m_paintingInsideReflection : 1;  // A state bit tracking if we are painting inside a replica.
    715     bool m_inOverflowRelayout : 1;
    716     bool m_needsFullRepaint : 1;
    717 
    718     bool m_overflowStatusDirty : 1;
    719     bool m_horizontalOverflow : 1;
    720     bool m_verticalOverflow : 1;
    721     bool m_visibleContentStatusDirty : 1;
    722     bool m_hasVisibleContent : 1;
    723     bool m_visibleDescendantStatusDirty : 1;
    724     bool m_hasVisibleDescendant : 1;
    725 
    726     bool m_isPaginated : 1; // If we think this layer is split by a multi-column ancestor, then this bit will be set.
    727 
    728     bool m_3DTransformedDescendantStatusDirty : 1;
    729     bool m_has3DTransformedDescendant : 1;  // Set on a stacking context layer that has 3D descendants anywhere
    730                                             // in a preserves3D hierarchy. Hint to do 3D-aware hit testing.
    731 #if USE(ACCELERATED_COMPOSITING)
    732     bool m_hasCompositingDescendant : 1; // In the z-order tree.
    733     bool m_mustOverlapCompositedLayers : 1;
    734 #if ENABLE(COMPOSITED_FIXED_ELEMENTS)
    735     bool m_shouldComposite : 1;
    736 #endif
    737 #endif
    738 #if PLATFORM(ANDROID)
    739     bool m_intrinsicallyComposited : 1;
    740 #endif
    741 
    742     bool m_containsDirtyOverlayScrollbars : 1;
    743 #if ENABLE(ANDROID_OVERFLOW_SCROLL)
    744     bool m_hasOverflowScroll : 1;
    745 #endif
    746 
    747     IntPoint m_cachedOverlayScrollbarOffset;
    748 
    749     RenderMarquee* m_marquee; // Used by layers with overflow:marquee
    750 
    751     // Cached normal flow values for absolute positioned elements with static left/top values.
    752     int m_staticInlinePosition;
    753     int m_staticBlockPosition;
    754 
    755     OwnPtr<TransformationMatrix> m_transform;
    756 
    757     // May ultimately be extended to many replicas (with their own paint order).
    758     RenderReplica* m_reflection;
    759 
    760     // Renderers to hold our custom scroll corner and resizer.
    761     RenderScrollbarPart* m_scrollCorner;
    762     RenderScrollbarPart* m_resizer;
    763 
    764 private:
    765     IntRect m_blockSelectionGapsBounds;
    766 
    767 #if USE(ACCELERATED_COMPOSITING)
    768     OwnPtr<RenderLayerBacking> m_backing;
    769 #endif
    770 
    771     Page* m_page;
    772 };
    773 
    774 } // namespace WebCore
    775 
    776 #ifndef NDEBUG
    777 // Outside the WebCore namespace for ease of invocation from gdb.
    778 void showLayerTree(const WebCore::RenderLayer*);
    779 void showLayerTree(const WebCore::RenderObject*);
    780 #endif
    781 
    782 #endif // RenderLayer_h
    783