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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrReducedClip_DEFINED
#define GrReducedClip_DEFINED
#include "GrWindowRectangles.h"
#include "SkClipStack.h"
#include "SkTLList.h"
class GrContext;
class GrRenderTargetContext;
/**
* This class takes a clip stack and produces a reduced set of elements that are equivalent to
* applying that full stack within a specified query rectangle.
*/
class SK_API GrReducedClip {
public:
GrReducedClip(const SkClipStack&, const SkRect& queryBounds, int maxWindowRectangles = 0);
/**
* If hasIBounds() is true, this is the bounding box within which the clip elements are valid.
* The caller must not modify any pixels outside this box. Undefined if hasIBounds() is false.
*/
const SkIRect& ibounds() const { SkASSERT(fHasIBounds); return fIBounds; }
int left() const { return this->ibounds().left(); }
int top() const { return this->ibounds().top(); }
int width() const { return this->ibounds().width(); }
int height() const { return this->ibounds().height(); }
/**
* Indicates whether ibounds() are defined. They will always be defined if the elements() are
* nonempty.
*/
bool hasIBounds() const { return fHasIBounds; }
/**
* If nonempty, this is a set of "exclusive" windows within which the clip elements are NOT
* valid. The caller must not modify any pixels inside these windows.
*/
const GrWindowRectangles& windowRectangles() const { return fWindowRects; }
typedef SkTLList<SkClipStack::Element, 16> ElementList;
/**
* Populated with a minimal list of elements required to fully implement the clip.
*/
const ElementList& elements() const { return fElements; }
/**
* If elements() are nonempty, uniquely identifies the list of elements within ibounds().
* Otherwise undefined.
*/
uint32_t elementsGenID() const { SkASSERT(!fElements.isEmpty()); return fElementsGenID; }
/**
* Indicates whether antialiasing is required to process any of the clip elements.
*/
bool requiresAA() const { return fRequiresAA; }
enum class InitialState : bool {
kAllIn,
kAllOut
};
InitialState initialState() const { return fInitialState; }
bool drawAlphaClipMask(GrRenderTargetContext*) const;
bool drawStencilClipMask(GrContext*, GrRenderTargetContext*) const;
private:
void walkStack(const SkClipStack&, const SkRect& queryBounds, int maxWindowRectangles);
void addInteriorWindowRectangles(int maxWindowRectangles);
void addWindowRectangle(const SkRect& elementInteriorRect, bool elementIsAA);
bool intersectIBounds(const SkIRect&);
SkIRect fIBounds;
bool fHasIBounds;
GrWindowRectangles fWindowRects;
ElementList fElements;
uint32_t fElementsGenID;
bool fRequiresAA;
InitialState fInitialState;
};
#endif