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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkEdgeBuilder_DEFINED
#define SkEdgeBuilder_DEFINED
#include "SkArenaAlloc.h"
#include "SkRect.h"
#include "SkTDArray.h"
#include "SkEdge.h"
#include "SkAnalyticEdge.h"
struct SkEdge;
struct SkAnalyticEdge;
class SkEdgeClipper;
class SkPath;
class SkEdgeBuilder {
public:
enum EdgeType {
// Used in supersampling or non-AA scan coverter; it stores only integral y coordinates.
kEdge,
// Used in Analytic AA scan converter; it uses SkFixed to store fractional y.
kAnalyticEdge,
// Used in Delta AA scan converter; it's a super-light wrapper of SkPoint, which can then be
// used to construct SkAnalyticEdge (kAnalyticEdge) later. We use kBezier to save the memory
// allocation time (a SkBezier is much lighter than SkAnalyticEdge or SkEdge). Note that
// Delta AA only has to deal with one SkAnalyticEdge at a time (whereas Analytic AA has to
// deal with all SkAnalyticEdges at the same time). Thus for Delta AA, we only need to
// allocate memory for n SkBeziers and 1 SkAnalyticEdge. (Analytic AA need to allocate
// memory for n SkAnalyticEdges.)
kBezier
};
// static constexpr int kEdgeSizes[3] = {sizeof(SkEdge), sizeof(SkAnalyticEdge), sizeof(SkBezier)};
SkEdgeBuilder();
// returns the number of built edges. The array of those edge pointers
// is returned from edgeList().
int build(const SkPath& path, const SkIRect* clip, int shiftUp, bool clipToTheRight,
EdgeType edgeType = kEdge);
int build_edges(const SkPath& path, const SkIRect* shiftedClip,
int shiftEdgesUp, bool pathContainedInClip, EdgeType edgeType = kEdge);
SkEdge** edgeList() { return (SkEdge**)fEdgeList; }
SkAnalyticEdge** analyticEdgeList() { return (SkAnalyticEdge**)fEdgeList; }
SkBezier** bezierList() { return (SkBezier**)fEdgeList; }
private:
enum Combine {
kNo_Combine,
kPartial_Combine,
kTotal_Combine
};
Combine CombineVertical(const SkEdge* edge, SkEdge* last);
Combine CombineVertical(const SkAnalyticEdge* edge, SkAnalyticEdge* last);
Combine checkVertical(const SkEdge* edge, SkEdge** edgePtr);
Combine checkVertical(const SkAnalyticEdge* edge, SkAnalyticEdge** edgePtr);
bool vertical_line(const SkEdge* edge);
bool vertical_line(const SkAnalyticEdge* edge);
SkSTArenaAlloc<512> fAlloc;
SkTDArray<void*> fList;
/*
* If we're in general mode, we allcoate the pointers in fList, and this
* will point at fList.begin(). If we're in polygon mode, fList will be
* empty, as we will have preallocated room for the pointers in fAlloc's
* block, and fEdgeList will point into that.
*/
void** fEdgeList;
int fShiftUp;
EdgeType fEdgeType;
public:
void addLine(const SkPoint pts[]);
void addQuad(const SkPoint pts[]);
void addCubic(const SkPoint pts[]);
void addClipper(SkEdgeClipper*);
EdgeType edgeType() const { return fEdgeType; }
int buildPoly(const SkPath& path, const SkIRect* clip, int shiftUp, bool clipToTheRight);
inline void addPolyLine(SkPoint pts[], char* &edge, size_t edgeSize, char** &edgePtr,
int shiftUp) {
if (fEdgeType == kBezier) {
if (((SkLine*)edge)->set(pts)) {
*edgePtr++ = edge;
edge += edgeSize;
}
return;
}
bool analyticAA = fEdgeType == kAnalyticEdge;
bool setLineResult = analyticAA ?
((SkAnalyticEdge*)edge)->setLine(pts[0], pts[1]) :
((SkEdge*)edge)->setLine(pts[0], pts[1], shiftUp);
if (setLineResult) {
Combine combine = analyticAA ?
checkVertical((SkAnalyticEdge*)edge, (SkAnalyticEdge**)edgePtr) :
checkVertical((SkEdge*)edge, (SkEdge**)edgePtr);
if (kNo_Combine == combine) {
*edgePtr++ = edge;
edge += edgeSize;
} else if (kTotal_Combine == combine) {
--edgePtr;
}
}
}
};
#endif
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