flutter_flutter/engine/core/rendering/RenderLayer.h

/*
 * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
 * Copyright (C) 2013 Intel Corporation. All rights reserved.
 *
 * Portions are Copyright (C) 1998 Netscape Communications Corporation.
 *
 * Other contributors:
 *   Robert O'Callahan <roc+@cs.cmu.edu>
 *   David Baron <dbaron@fas.harvard.edu>
 *   Christian Biesinger <cbiesinger@web.de>
 *   Randall Jesup <rjesup@wgate.com>
 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
 *   Josh Soref <timeless@mac.com>
 *   Boris Zbarsky <bzbarsky@mit.edu>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Alternatively, the contents of this file may be used under the terms
 * of either the Mozilla Public License Version 1.1, found at
 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
 * (the "GPL"), in which case the provisions of the MPL or the GPL are
 * applicable instead of those above.  If you wish to allow use of your
 * version of this file only under the terms of one of those two
 * licenses (the MPL or the GPL) and not to allow others to use your
 * version of this file under the LGPL, indicate your decision by
 * deletingthe provisions above and replace them with the notice and
 * other provisions required by the MPL or the GPL, as the case may be.
 * If you do not delete the provisions above, a recipient may use your
 * version of this file under any of the LGPL, the MPL or the GPL.
 */

#ifndef SKY_ENGINE_CORE_RENDERING_RENDERLAYER_H_
#define SKY_ENGINE_CORE_RENDERING_RENDERLAYER_H_

#include "sky/engine/core/rendering/LayerPaintingInfo.h"
#include "sky/engine/core/rendering/RenderBox.h"
#include "sky/engine/core/rendering/RenderLayerClipper.h"
#include "sky/engine/core/rendering/RenderLayerFilterInfo.h"
#include "sky/engine/core/rendering/RenderLayerStackingNode.h"
#include "sky/engine/core/rendering/RenderLayerStackingNodeIterator.h"
#include "sky/engine/public/platform/WebBlendMode.h"
#include "sky/engine/wtf/OwnPtr.h"

namespace blink {

class FilterEffectRenderer;
class FilterOperations;
class HitTestRequest;
class HitTestResult;
class HitTestingTransformState;
class RenderStyle;
class TransformationMatrix;

enum BorderRadiusClippingRule { IncludeSelfForBorderRadius, DoNotIncludeSelfForBorderRadius };
enum IncludeSelfOrNot { IncludeSelf, ExcludeSelf };

class RenderLayer {
    WTF_MAKE_NONCOPYABLE(RenderLayer);
public:
    RenderLayer(RenderLayerModelObject*, LayerType);
    ~RenderLayer();

    String debugName() const;

    RenderLayerModelObject* renderer() const { return m_renderer; }
    RenderBox* renderBox() const { return m_renderer && m_renderer->isBox() ? toRenderBox(m_renderer) : 0; }
    RenderLayer* parent() const { return m_parent; }
    RenderLayer* previousSibling() const { return m_previous; }
    RenderLayer* nextSibling() const { return m_next; }
    RenderLayer* firstChild() const { return m_first; }
    RenderLayer* lastChild() const { return m_last; }

    void addChild(RenderLayer* newChild, RenderLayer* beforeChild = 0);
    RenderLayer* removeChild(RenderLayer*);

    void removeOnlyThisLayer();
    void insertOnlyThisLayer();

    void styleChanged(StyleDifference, const RenderStyle* oldStyle);

    // FIXME: Many people call this function while it has out-of-date information.
    bool isSelfPaintingLayer() const { return m_isSelfPaintingLayer; }

    void setLayerType(LayerType layerType) { m_layerType = layerType; }

    bool isTransparent() const { return renderer()->isTransparent(); }
    RenderLayer* transparentPaintingAncestor();
    void beginTransparencyLayers(GraphicsContext*, const RenderLayer* rootLayer, const LayoutRect& paintDirtyRect, const LayoutSize& subPixelAccumulation);

    const RenderLayer* root() const
    {
        const RenderLayer* curr = this;
        while (curr->parent())
            curr = curr->parent();
        return curr;
    }

    LayoutPoint location() const;
    IntSize size() const;

    LayoutRect rect() const { return LayoutRect(location(), size()); }

    bool isRootLayer() const { return m_isRootLayer; }

    void updateLayerPositionsAfterLayout();

    void updateTransformationMatrix();
    RenderLayer* renderingContextRoot();

    // Our current relative position offset.
    const LayoutSize offsetForInFlowPosition() const;

    RenderLayerStackingNode* stackingNode() { return m_stackingNode.get(); }
    const RenderLayerStackingNode* stackingNode() const { return m_stackingNode.get(); }

    bool hasBoxDecorationsOrBackground() const;
    bool hasVisibleBoxDecorations() const;
    // Returns true if this layer has visible content (ignoring any child layers).
    bool isVisuallyNonEmpty() const;
    // True if this layer container renderers that paint.
    bool hasNonEmptyChildRenderers() const;

    bool usedTransparency() const { return m_usedTransparency; }
    void clearUsedTransparency() { m_usedTransparency = false; }

    // Gets the nearest enclosing positioned ancestor layer (also includes
    // the <html> layer and the root layer).
    RenderLayer* enclosingPositionedAncestor() const;

    RenderLayer* enclosingOverflowClipLayer(IncludeSelfOrNot = IncludeSelf) const;

    const RenderLayer* compositingContainer() const;
    RenderLayer* enclosingFilterLayer(IncludeSelfOrNot = IncludeSelf) const;
    bool hasAncestorWithFilterOutsets() const;

    void convertToLayerCoords(const RenderLayer* ancestorLayer, LayoutPoint&) const;
    void convertToLayerCoords(const RenderLayer* ancestorLayer, LayoutRect&) const;

    // The hitTest method looks for mouse events by walking
    // layers that intersect the point from front to back.
    bool hitTest(const HitTestRequest&, const HitTestLocation&, HitTestResult&);

    // Pass offsetFromRoot if known.
    bool intersectsDamageRect(const LayoutRect& layerBounds, const LayoutRect& damageRect, const RenderLayer* rootLayer, const LayoutPoint* offsetFromRoot = 0) const;

    // Bounding box relative to some ancestor layer. Pass offsetFromRoot if known.
    LayoutRect physicalBoundingBox(const RenderLayer* ancestorLayer, const LayoutPoint* offsetFromRoot = 0) const;
    LayoutRect physicalBoundingBoxIncludingReflectionAndStackingChildren(const RenderLayer* ancestorLayer, const LayoutPoint& offsetFromRoot) const;

    // If true, this layer's children are included in its bounds for overlap testing.
    // We can't rely on the children's positions if this layer has a filter that could have moved the children's pixels around.
    bool overlapBoundsIncludeChildren() const { return hasFilter() && renderer()->style()->filter().hasFilterThatMovesPixels(); }

    LayoutRect boundingBoxForCompositing(const RenderLayer* ancestorLayer = 0) const;

    LayoutUnit staticInlinePosition() const { return m_staticInlinePosition; }
    LayoutUnit staticBlockPosition() const { return m_staticBlockPosition; }

    void setStaticInlinePosition(LayoutUnit position) { m_staticInlinePosition = position; }
    void setStaticBlockPosition(LayoutUnit position) { m_staticBlockPosition = position; }

    LayoutSize subpixelAccumulation() const;
    void setSubpixelAccumulation(const LayoutSize&);

    bool hasTransform() const { return renderer()->hasTransform(); }
    // Note that this transform has the transform-origin baked in.
    TransformationMatrix* transform() const { return m_transform.get(); }
    // currentTransform computes a transform which takes accelerated animations into account. The
    // resulting transform has transform-origin baked in. If the layer does not have a transform,
    // returns the identity matrix.
    TransformationMatrix currentTransform(RenderStyle::ApplyTransformOrigin = RenderStyle::IncludeTransformOrigin) const;
    TransformationMatrix renderableTransform() const;

    // Get the perspective transform, which is applied to transformed sublayers.
    // Returns true if the layer has a -webkit-perspective.
    // Note that this transform has the perspective-origin baked in.
    TransformationMatrix perspectiveTransform() const;
    FloatPoint perspectiveOrigin() const;
    bool preserves3D() const { return renderer()->style()->transformStyle3D() == TransformStyle3DPreserve3D; }
    bool has3DTransform() const { return m_transform && !m_transform->isAffine(); }

    // FIXME: reflections should force transform-style to be flat in the style: https://bugs.webkit.org/show_bug.cgi?id=106959
    bool shouldPreserve3D() const { return renderer()->style()->transformStyle3D() == TransformStyle3DPreserve3D; }

    bool hasFilter() const { return renderer()->hasFilter(); }

    void* operator new(size_t);
    // Only safe to call from RenderLayerModelObject::destroyLayer()
    void operator delete(void*);

    bool paintsWithTransform() const;

    FilterOperations computeFilterOperations(const RenderStyle*);
    bool paintsWithFilters() const;
    bool requiresFullLayerImageForFilters() const;
    FilterEffectRenderer* filterRenderer() const
    {
        RenderLayerFilterInfo* filterInfo = this->filterInfo();
        return filterInfo ? filterInfo->renderer() : 0;
    }

    RenderLayerFilterInfo* filterInfo() const { return hasFilterInfo() ? RenderLayerFilterInfo::filterInfoForRenderLayer(this) : 0; }
    RenderLayerFilterInfo* ensureFilterInfo() { return RenderLayerFilterInfo::createFilterInfoForRenderLayerIfNeeded(this); }
    void removeFilterInfoIfNeeded()
    {
        if (hasFilterInfo())
            RenderLayerFilterInfo::removeFilterInfoForRenderLayer(this);
    }

    bool hasFilterInfo() const { return m_hasFilterInfo; }
    void setHasFilterInfo(bool hasFilterInfo) { m_hasFilterInfo = hasFilterInfo; }

    void updateFilters(const RenderStyle* oldStyle, const RenderStyle* newStyle);

    Node* enclosingElement() const;

    RenderLayerClipper& clipper() { return m_clipper; }
    const RenderLayerClipper& clipper() const { return m_clipper; }

    inline bool isPositionedContainer() const
    {
        // FIXME: This is not in sync with containingBlock.
        RenderLayerModelObject* layerRenderer = renderer();
        return isRootLayer() || layerRenderer->isPositioned() || hasTransform();
    }

    void updateOrRemoveFilterEffectRenderer();
    void updateSelfPaintingLayer();

    void clipToRect(const LayerPaintingInfo&, GraphicsContext*, const ClipRect&, BorderRadiusClippingRule = IncludeSelfForBorderRadius);
    void restoreClip(GraphicsContext*, const LayoutRect& paintDirtyRect, const ClipRect&);

private:
    // TODO(ojan): Get rid of this. These are basically layer-tree-only paint phases.
    enum PaintLayerFlags {
        PaintContent,
    };

    // Bounding box in the coordinates of this layer.
    LayoutRect logicalBoundingBox() const;

    void setAncestorChainHasSelfPaintingLayerDescendant();
    void dirtyAncestorChainHasSelfPaintingLayerDescendantStatus();

    void setNextSibling(RenderLayer* next) { m_next = next; }
    void setPreviousSibling(RenderLayer* prev) { m_previous = prev; }
    void setFirstChild(RenderLayer* first) { m_first = first; }
    void setLastChild(RenderLayer* last) { m_last = last; }

    void updateHasSelfPaintingLayerDescendant() const;

    bool hasSelfPaintingLayerDescendant() const
    {
        if (m_hasSelfPaintingLayerDescendantDirty)
            updateHasSelfPaintingLayerDescendant();
        ASSERT(!m_hasSelfPaintingLayerDescendantDirty);
        return m_hasSelfPaintingLayerDescendant;
    }

    LayoutPoint renderBoxLocation() const { return renderer()->isBox() ? toRenderBox(renderer())->location() : LayoutPoint(); }

    RenderLayer* hitTestLayer(RenderLayer* rootLayer, RenderLayer* containerLayer, const HitTestRequest& request, HitTestResult& result,
                              const LayoutRect& hitTestRect, const HitTestLocation&,
                              const HitTestingTransformState* transformState = 0, double* zOffset = 0);
    RenderLayer* hitTestChildren(ChildrenIteration, RenderLayer* rootLayer, const HitTestRequest&, HitTestResult&,
                             const LayoutRect& hitTestRect, const HitTestLocation&,
                             const HitTestingTransformState* transformState, double* zOffsetForDescendants, double* zOffset,
                             const HitTestingTransformState* unflattenedTransformState, bool depthSortDescendants);

    PassRefPtr<HitTestingTransformState> createLocalTransformState(RenderLayer* rootLayer, RenderLayer* containerLayer,
                            const LayoutRect& hitTestRect, const HitTestLocation&,
                            const HitTestingTransformState* containerTransformState,
                            const LayoutPoint& translationOffset = LayoutPoint()) const;

    bool hitTestContents(const HitTestRequest&, HitTestResult&, const LayoutRect& layerBounds, const HitTestLocation&) const;

    bool shouldBeSelfPaintingLayer() const;

    // FIXME: We should only create the stacking node if needed.
    bool requiresStackingNode() const { return true; }
    void updateStackingNode();

    void updateTransform(const RenderStyle* oldStyle, RenderStyle* newStyle);

    void dirty3DTransformedDescendantStatus();
    // Both updates the status, and returns true if descendants of this have 3d.
    bool update3DTransformedDescendantStatus();

    void updateOrRemoveFilterClients();

    LayoutRect paintingExtent(const RenderLayer* rootLayer, const LayoutRect& paintDirtyRect, const LayoutSize& subPixelAccumulation);

    LayerType m_layerType;

    // Self-painting layer is an optimization where we avoid the heavy RenderLayer painting
    // machinery for a RenderLayer allocated only to handle the overflow clip case.
    // FIXME(crbug.com/332791): Self-painting layer should be merged into the overflow-only concept.
    unsigned m_isSelfPaintingLayer : 1;

    // If have no self-painting descendants, we don't have to walk our children during painting. This can lead to
    // significant savings, especially if the tree has lots of non-self-painting layers grouped together (e.g. table cells).
    mutable unsigned m_hasSelfPaintingLayerDescendant : 1;
    mutable unsigned m_hasSelfPaintingLayerDescendantDirty : 1;

    const unsigned m_isRootLayer : 1;

    unsigned m_usedTransparency : 1; // Tracks whether we need to close a transparent layer, i.e., whether
                                 // we ended up painting this layer or any descendants (and therefore need to
                                 // blend).

    unsigned m_3DTransformedDescendantStatusDirty : 1;
    // Set on a stacking context layer that has 3D descendants anywhere
    // in a preserves3D hierarchy. Hint to do 3D-aware hit testing.
    unsigned m_has3DTransformedDescendant : 1;

    unsigned m_hasFilterInfo : 1;

    RenderLayerModelObject* m_renderer;

    RenderLayer* m_parent;
    RenderLayer* m_previous;
    RenderLayer* m_next;
    RenderLayer* m_first;
    RenderLayer* m_last;

    // Cached normal flow values for absolute positioned elements with static left/top values.
    LayoutUnit m_staticInlinePosition;
    LayoutUnit m_staticBlockPosition;

    OwnPtr<TransformationMatrix> m_transform;

    RenderLayerClipper m_clipper; // FIXME: Lazily allocate?
    OwnPtr<RenderLayerStackingNode> m_stackingNode;

    LayoutSize m_subpixelAccumulation; // The accumulated subpixel offset of a composited layer's composited bounds compared to absolute coordinates.
};

} // namespace blink

#ifndef NDEBUG
// Outside the WebCore namespace for ease of invocation from gdb.
void showLayerTree(const blink::RenderLayer*);
void showLayerTree(const blink::RenderObject*);
#endif

#endif  // SKY_ENGINE_CORE_RENDERING_RENDERLAYER_H_