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      1 /*
      2  * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org)
      3  *           (C) 1999 Antti Koivisto (koivisto (at) kde.org)
      4  *           (C) 2005 Allan Sandfeld Jensen (kde (at) carewolf.com)
      5  *           (C) 2005, 2006 Samuel Weinig (sam.weinig (at) gmail.com)
      6  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
      7  * Copyright (C) 2010, 2012 Google Inc. All rights reserved.
      8  *
      9  * This library is free software; you can redistribute it and/or
     10  * modify it under the terms of the GNU Library General Public
     11  * License as published by the Free Software Foundation; either
     12  * version 2 of the License, or (at your option) any later version.
     13  *
     14  * This library is distributed in the hope that it will be useful,
     15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     17  * Library General Public License for more details.
     18  *
     19  * You should have received a copy of the GNU Library General Public License
     20  * along with this library; see the file COPYING.LIB.  If not, write to
     21  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     22  * Boston, MA 02110-1301, USA.
     23  */
     24 
     25 #include "config.h"
     26 #include "core/rendering/RenderLayerModelObject.h"
     27 
     28 #include "core/rendering/RenderLayer.h"
     29 #include "core/rendering/RenderView.h"
     30 
     31 using namespace std;
     32 
     33 namespace WebCore {
     34 
     35 bool RenderLayerModelObject::s_wasFloating = false;
     36 bool RenderLayerModelObject::s_hadLayer = false;
     37 bool RenderLayerModelObject::s_hadTransform = false;
     38 bool RenderLayerModelObject::s_layerWasSelfPainting = false;
     39 
     40 RenderLayerModelObject::RenderLayerModelObject(ContainerNode* node)
     41     : RenderObject(node)
     42     , m_layer(0)
     43 {
     44 }
     45 
     46 RenderLayerModelObject::~RenderLayerModelObject()
     47 {
     48     // Our layer should have been destroyed and cleared by now
     49     ASSERT(!hasLayer());
     50     ASSERT(!m_layer);
     51 }
     52 
     53 void RenderLayerModelObject::destroyLayer()
     54 {
     55     ASSERT(!hasLayer()); // Callers should have already called setHasLayer(false)
     56     ASSERT(m_layer);
     57     delete m_layer;
     58     m_layer = 0;
     59 }
     60 
     61 void RenderLayerModelObject::ensureLayer()
     62 {
     63     if (m_layer)
     64         return;
     65 
     66     m_layer = new RenderLayer(this);
     67     setHasLayer(true);
     68     m_layer->insertOnlyThisLayer();
     69 }
     70 
     71 bool RenderLayerModelObject::hasSelfPaintingLayer() const
     72 {
     73     return m_layer && m_layer->isSelfPaintingLayer();
     74 }
     75 
     76 void RenderLayerModelObject::willBeDestroyed()
     77 {
     78     if (isPositioned()) {
     79         // Don't use this->view() because the document's renderView has been set to 0 during destruction.
     80         if (Frame* frame = this->frame()) {
     81             if (FrameView* frameView = frame->view()) {
     82                 if (style()->hasViewportConstrainedPosition())
     83                     frameView->removeViewportConstrainedObject(this);
     84             }
     85         }
     86     }
     87 
     88     // RenderObject::willBeDestroyed calls back to destroyLayer() for layer destruction
     89     RenderObject::willBeDestroyed();
     90 }
     91 
     92 void RenderLayerModelObject::styleWillChange(StyleDifference diff, const RenderStyle* newStyle)
     93 {
     94     s_wasFloating = isFloating();
     95     s_hadLayer = hasLayer();
     96     s_hadTransform = hasTransform();
     97     if (s_hadLayer)
     98         s_layerWasSelfPainting = layer()->isSelfPaintingLayer();
     99 
    100     // If our z-index changes value or our visibility changes,
    101     // we need to dirty our stacking context's z-order list.
    102     RenderStyle* oldStyle = style();
    103     if (oldStyle && newStyle) {
    104         if (parent()) {
    105             // Do a repaint with the old style first, e.g., for example if we go from
    106             // having an outline to not having an outline.
    107             if (diff == StyleDifferenceRepaintLayer) {
    108                 layer()->repaintIncludingDescendants();
    109                 if (!(oldStyle->clip() == newStyle->clip()))
    110                     layer()->clearClipRectsIncludingDescendants();
    111             } else if (diff == StyleDifferenceRepaint || newStyle->outlineSize() < oldStyle->outlineSize())
    112                 repaint();
    113         }
    114 
    115         if (diff == StyleDifferenceLayout || diff == StyleDifferenceSimplifiedLayout) {
    116             // When a layout hint happens, we go ahead and do a repaint of the layer, since the layer could
    117             // end up being destroyed.
    118             if (hasLayer()) {
    119                 if (oldStyle->position() != newStyle->position()
    120                     || oldStyle->zIndex() != newStyle->zIndex()
    121                     || oldStyle->hasAutoZIndex() != newStyle->hasAutoZIndex()
    122                     || !(oldStyle->clip() == newStyle->clip())
    123                     || oldStyle->hasClip() != newStyle->hasClip()
    124                     || oldStyle->opacity() != newStyle->opacity()
    125                     || oldStyle->transform() != newStyle->transform()
    126                     || oldStyle->filter() != newStyle->filter()
    127                     )
    128                 layer()->repaintIncludingDescendants();
    129             } else if (newStyle->hasTransform() || newStyle->opacity() < 1 || newStyle->hasFilter()) {
    130                 // If we don't have a layer yet, but we are going to get one because of transform or opacity,
    131                 //  then we need to repaint the old position of the object.
    132                 repaint();
    133             }
    134         }
    135     }
    136 
    137     RenderObject::styleWillChange(diff, newStyle);
    138 }
    139 
    140 void RenderLayerModelObject::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
    141 {
    142     RenderObject::styleDidChange(diff, oldStyle);
    143     updateFromStyle();
    144 
    145     if (requiresLayer()) {
    146         if (!layer() && layerCreationAllowedForSubtree()) {
    147             if (s_wasFloating && isFloating())
    148                 setChildNeedsLayout();
    149             ensureLayer();
    150             if (parent() && !needsLayout() && containingBlock()) {
    151                 layer()->setRepaintStatus(NeedsFullRepaint);
    152                 // There is only one layer to update, it is not worth using |cachedOffset| since
    153                 // we are not sure the value will be used.
    154                 layer()->updateLayerPositions(0);
    155             }
    156         }
    157     } else if (layer() && layer()->parent()) {
    158         setHasTransform(false); // Either a transform wasn't specified or the object doesn't support transforms, so just null out the bit.
    159         setHasReflection(false);
    160         layer()->removeOnlyThisLayer(); // calls destroyLayer() which clears m_layer
    161         if (s_wasFloating && isFloating())
    162             setChildNeedsLayout();
    163         if (s_hadTransform)
    164             setNeedsLayoutAndPrefWidthsRecalc();
    165     }
    166 
    167     if (layer()) {
    168         layer()->styleChanged(diff, oldStyle);
    169         if (s_hadLayer && layer()->isSelfPaintingLayer() != s_layerWasSelfPainting)
    170             setChildNeedsLayout();
    171     }
    172 
    173     if (FrameView *frameView = view()->frameView()) {
    174         bool newStyleIsViewportConstained = style()->hasViewportConstrainedPosition();
    175         bool oldStyleIsViewportConstrained = oldStyle && oldStyle->hasViewportConstrainedPosition();
    176         if (newStyleIsViewportConstained != oldStyleIsViewportConstrained) {
    177             if (newStyleIsViewportConstained && layer())
    178                 frameView->addViewportConstrainedObject(this);
    179             else
    180                 frameView->removeViewportConstrainedObject(this);
    181         }
    182     }
    183 }
    184 
    185 void RenderLayerModelObject::addLayerHitTestRects(LayerHitTestRects& rects, const RenderLayer* currentLayer, const LayoutPoint& layerOffset, const LayoutRect& containerRect) const
    186 {
    187     if (hasLayer()) {
    188         if (isRenderView()) {
    189             // RenderView is handled with a special fast-path, but it needs to know the current layer.
    190             RenderObject::addLayerHitTestRects(rects, layer(), LayoutPoint(), LayoutRect());
    191         } else {
    192             // Since a RenderObject never lives outside it's container RenderLayer, we can switch
    193             // to marking entire layers instead. This may sometimes mark more than necessary (when
    194             // a layer is made of disjoint objects) but in practice is a significant performance
    195             // savings.
    196             layer()->addLayerHitTestRects(rects);
    197         }
    198     } else {
    199         RenderObject::addLayerHitTestRects(rects, currentLayer, layerOffset, containerRect);
    200     }
    201 }
    202 
    203 } // namespace WebCore
    204 
    205