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132 lines
4.3 KiB
132 lines
4.3 KiB
/*
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* Copyright 2018 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkContourMeasure_DEFINED
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#define SkContourMeasure_DEFINED
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#include "include/core/SkPath.h"
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#include "include/core/SkRefCnt.h"
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#include "include/private/SkTDArray.h"
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struct SkConic;
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class SK_API SkContourMeasure : public SkRefCnt {
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public:
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/** Return the length of the contour.
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*/
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SkScalar length() const { return fLength; }
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/** Pins distance to 0 <= distance <= length(), and then computes the corresponding
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* position and tangent.
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*/
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bool SK_WARN_UNUSED_RESULT getPosTan(SkScalar distance, SkPoint* position,
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SkVector* tangent) const;
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enum MatrixFlags {
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kGetPosition_MatrixFlag = 0x01,
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kGetTangent_MatrixFlag = 0x02,
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kGetPosAndTan_MatrixFlag = kGetPosition_MatrixFlag | kGetTangent_MatrixFlag
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};
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/** Pins distance to 0 <= distance <= getLength(), and then computes
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the corresponding matrix (by calling getPosTan).
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Returns false if there is no path, or a zero-length path was specified, in which case
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matrix is unchanged.
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*/
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bool SK_WARN_UNUSED_RESULT getMatrix(SkScalar distance, SkMatrix* matrix,
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MatrixFlags flags = kGetPosAndTan_MatrixFlag) const;
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/** Given a start and stop distance, return in dst the intervening segment(s).
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If the segment is zero-length, return false, else return true.
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startD and stopD are pinned to legal values (0..getLength()). If startD > stopD
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then return false (and leave dst untouched).
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Begin the segment with a moveTo if startWithMoveTo is true
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*/
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bool SK_WARN_UNUSED_RESULT getSegment(SkScalar startD, SkScalar stopD, SkPath* dst,
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bool startWithMoveTo) const;
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/** Return true if the contour is closed()
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*/
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bool isClosed() const { return fIsClosed; }
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private:
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struct Segment {
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SkScalar fDistance; // total distance up to this point
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unsigned fPtIndex; // index into the fPts array
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unsigned fTValue : 30;
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unsigned fType : 2; // actually the enum SkSegType
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// See SkPathMeasurePriv.h
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SkScalar getScalarT() const;
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static const Segment* Next(const Segment* seg) {
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unsigned ptIndex = seg->fPtIndex;
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do {
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++seg;
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} while (seg->fPtIndex == ptIndex);
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return seg;
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}
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};
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const SkTDArray<Segment> fSegments;
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const SkTDArray<SkPoint> fPts; // Points used to define the segments
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const SkScalar fLength;
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const bool fIsClosed;
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SkContourMeasure(SkTDArray<Segment>&& segs, SkTDArray<SkPoint>&& pts,
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SkScalar length, bool isClosed);
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~SkContourMeasure() override {}
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const Segment* distanceToSegment(SkScalar distance, SkScalar* t) const;
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friend class SkContourMeasureIter;
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};
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class SK_API SkContourMeasureIter {
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public:
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SkContourMeasureIter();
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/**
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* Initialize the Iter with a path.
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* The parts of the path that are needed are copied, so the client is free to modify/delete
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* the path after this call.
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*
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* resScale controls the precision of the measure. values > 1 increase the
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* precision (and possibly slow down the computation).
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*/
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SkContourMeasureIter(const SkPath& path, bool forceClosed, SkScalar resScale = 1);
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~SkContourMeasureIter();
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/**
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* Reset the Iter with a path.
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* The parts of the path that are needed are copied, so the client is free to modify/delete
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* the path after this call.
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*/
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void reset(const SkPath& path, bool forceClosed, SkScalar resScale = 1);
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/**
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* Iterates through contours in path, returning a contour-measure object for each contour
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* in the path. Returns null when it is done.
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*
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* This only returns non-zero length contours, where a contour is the segments between
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* a kMove_Verb and either ...
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* - the next kMove_Verb
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* - kClose_Verb (1 or more)
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* - kDone_Verb
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* If it encounters a zero-length contour, it is skipped.
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*/
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sk_sp<SkContourMeasure> next();
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private:
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class Impl;
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std::unique_ptr<Impl> fImpl;
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};
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#endif
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