The Tor Browser: comparison gfx/skia/trunk/include/core/SkPathRef.h

--1:000000000000
+:cef72d13cd82
+/*
+* Copyright 2012 Google Inc.
+*
+* Use of this source code is governed by a BSD-style license that can be
+* found in the LICENSE file.
+*/
+#ifndef SkPathRef_DEFINED
+#define SkPathRef_DEFINED
+#include "SkMatrix.h"
+#include "SkPoint.h"
+#include "SkRect.h"
+#include "SkRefCnt.h"
+#include "SkTDArray.h"
+#include <stddef.h> // ptrdiff_t
+class SkRBuffer;
+class SkWBuffer;
+/**
+* Holds the path verbs and points. It is versioned by a generation ID. None of its public methods
+* modify the contents. To modify or append to the verbs/points wrap the SkPathRef in an
+* SkPathRef::Editor object. Installing the editor resets the generation ID. It also performs
+* copy-on-write if the SkPathRef is shared by multiple SkPaths. The caller passes the Editor's
+* constructor a SkAutoTUnref, which may be updated to point to a new SkPathRef after the editor's
+* constructor returns.
+*
+* The points and verbs are stored in a single allocation. The points are at the begining of the
+* allocation while the verbs are stored at end of the allocation, in reverse order. Thus the points
+* and verbs both grow into the middle of the allocation until the meet. To access verb i in the
+* verb array use ref.verbs()[~i] (because verbs() returns a pointer just beyond the first
+* logical verb or the last verb in memory).
+*/
+class SK_API SkPathRef : public ::SkRefCnt {
+public:
+SK_DECLARE_INST_COUNT(SkPathRef);
+class Editor {
+public:
+Editor(SkAutoTUnref<SkPathRef>* pathRef,
+int incReserveVerbs = 0,
+int incReservePoints = 0);
+~Editor() { SkDEBUGCODE(sk_atomic_dec(&fPathRef->fEditorsAttached);) }
+/**
+* Returns the array of points.
+*/
+SkPoint* points() { return fPathRef->getPoints(); }
+const SkPoint* points() const { return fPathRef->points(); }
+/**
+* Gets the ith point. Shortcut for this->points() + i
+*/
+SkPoint* atPoint(int i) {
+SkASSERT((unsigned) i < (unsigned) fPathRef->fPointCnt);
+return this->points() + i;
+};
+const SkPoint* atPoint(int i) const {
+SkASSERT((unsigned) i < (unsigned) fPathRef->fPointCnt);
+return this->points() + i;
+};
+/**
+* Adds the verb and allocates space for the number of points indicated by the verb. The
+* return value is a pointer to where the points for the verb should be written.
+* 'weight' is only used if 'verb' is kConic_Verb
+*/
+SkPoint* growForVerb(int /*SkPath::Verb*/ verb, SkScalar weight = 0) {
+SkDEBUGCODE(fPathRef->validate();)
+return fPathRef->growForVerb(verb, weight);
+}
+/**
+* Allocates space for multiple instances of a particular verb and the
+* requisite points & weights.
+* The return pointer points at the first new point (indexed normally [<i>]).
+* If 'verb' is kConic_Verb, 'weights' will return a pointer to the
+* space for the conic weights (indexed normally).
+*/
+SkPoint* growForRepeatedVerb(int /*SkPath::Verb*/ verb,
+int numVbs,
+SkScalar** weights = NULL) {
+return fPathRef->growForRepeatedVerb(verb, numVbs, weights);
+}
+/**
+* Resets the path ref to a new verb and point count. The new verbs and points are
+* uninitialized.
+*/
+void resetToSize(int newVerbCnt, int newPointCnt, int newConicCount) {
+fPathRef->resetToSize(newVerbCnt, newPointCnt, newConicCount);
+}
+/**
+* Gets the path ref that is wrapped in the Editor.
+*/
+SkPathRef* pathRef() { return fPathRef; }
+void setIsOval(bool isOval) { fPathRef->setIsOval(isOval); }
+void setBounds(const SkRect& rect) { fPathRef->setBounds(rect); }
+private:
+SkPathRef* fPathRef;
+};
+public:
+/**
+* Gets a path ref with no verbs or points.
+*/
+static SkPathRef* CreateEmpty();
+/**
+*  Returns true if all of the points in this path are finite, meaning there
+*  are no infinities and no NaNs.
+*/
+bool isFinite() const {
+if (fBoundsIsDirty) {
+this->computeBounds();
+}
+return SkToBool(fIsFinite);
+}
+/**
+*  Returns a mask, where each bit corresponding to a SegmentMask is
+*  set if the path contains 1 or more segments of that type.
+*  Returns 0 for an empty path (no segments).
+*/
+uint32_t getSegmentMasks() const { return fSegmentMask; }
+/** Returns true if the path is an oval.
+*
+* @param rect      returns the bounding rect of this oval. It's a circle
+*                  if the height and width are the same.
+*
+* @return true if this path is an oval.
+*              Tracking whether a path is an oval is considered an
+*              optimization for performance and so some paths that are in
+*              fact ovals can report false.
+*/
+bool isOval(SkRect* rect) const {
+if (fIsOval && NULL != rect) {
+*rect = getBounds();
+}
+return SkToBool(fIsOval);
+}
+bool hasComputedBounds() const {
+return !fBoundsIsDirty;
+}
+/** Returns the bounds of the path's points. If the path contains 0 or 1
+points, the bounds is set to (0,0,0,0), and isEmpty() will return true.
+Note: this bounds may be larger than the actual shape, since curves
+do not extend as far as their control points.
+*/
+const SkRect& getBounds() const {
+if (fBoundsIsDirty) {
+this->computeBounds();
+}
+return fBounds;
+}
+/**
+* Transforms a path ref by a matrix, allocating a new one only if necessary.
+*/
+static void CreateTransformedCopy(SkAutoTUnref<SkPathRef>* dst,
+const SkPathRef& src,
+const SkMatrix& matrix);
+static SkPathRef* CreateFromBuffer(SkRBuffer* buffer);
+/**
+* Rollsback a path ref to zero verbs and points with the assumption that the path ref will be
+* repopulated with approximately the same number of verbs and points. A new path ref is created
+* only if necessary.
+*/
+static void Rewind(SkAutoTUnref<SkPathRef>* pathRef);
+virtual ~SkPathRef() {
+SkDEBUGCODE(this->validate();)
+sk_free(fPoints);
+SkDEBUGCODE(fPoints = NULL;)
+SkDEBUGCODE(fVerbs = NULL;)
+SkDEBUGCODE(fVerbCnt = 0x9999999;)
+SkDEBUGCODE(fPointCnt = 0xAAAAAAA;)
+SkDEBUGCODE(fPointCnt = 0xBBBBBBB;)
+SkDEBUGCODE(fGenerationID = 0xEEEEEEEE;)
+SkDEBUGCODE(fEditorsAttached = 0x7777777;)
+}
+int countPoints() const { SkDEBUGCODE(this->validate();) return fPointCnt; }
+int countVerbs() const { SkDEBUGCODE(this->validate();) return fVerbCnt; }
+int countWeights() const { SkDEBUGCODE(this->validate();) return fConicWeights.count(); }
+/**
+* Returns a pointer one beyond the first logical verb (last verb in memory order).
+*/
+const uint8_t* verbs() const { SkDEBUGCODE(this->validate();) return fVerbs; }
+/**
+* Returns a const pointer to the first verb in memory (which is the last logical verb).
+*/
+const uint8_t* verbsMemBegin() const { return this->verbs() - fVerbCnt; }
+/**
+* Returns a const pointer to the first point.
+*/
+const SkPoint* points() const { SkDEBUGCODE(this->validate();) return fPoints; }
+/**
+* Shortcut for this->points() + this->countPoints()
+*/
+const SkPoint* pointsEnd() const { return this->points() + this->countPoints(); }
+const SkScalar* conicWeights() const { SkDEBUGCODE(this->validate();) return fConicWeights.begin(); }
+const SkScalar* conicWeightsEnd() const { SkDEBUGCODE(this->validate();) return fConicWeights.end(); }
+/**
+* Convenience methods for getting to a verb or point by index.
+*/
+uint8_t atVerb(int index) const {
+SkASSERT((unsigned) index < (unsigned) fVerbCnt);
+return this->verbs()[~index];
+}
+const SkPoint& atPoint(int index) const {
+SkASSERT((unsigned) index < (unsigned) fPointCnt);
+return this->points()[index];
+}
+bool operator== (const SkPathRef& ref) const;
+/**
+* Writes the path points and verbs to a buffer.
+*/
+void writeToBuffer(SkWBuffer* buffer) const;
+/**
+* Gets the number of bytes that would be written in writeBuffer()
+*/
+uint32_t writeSize() const;
+/**
+* Gets an ID that uniquely identifies the contents of the path ref. If two path refs have the
+* same ID then they have the same verbs and points. However, two path refs may have the same
+* contents but different genIDs.
+*/
+uint32_t genID() const;
+private:
+enum SerializationOffsets {
+kIsFinite_SerializationShift = 25,  // requires 1 bit
+kIsOval_SerializationShift = 24,    // requires 1 bit
+kSegmentMask_SerializationShift = 0 // requires 4 bits
+};
+SkPathRef() {
+fBoundsIsDirty = true;    // this also invalidates fIsFinite
+fPointCnt = 0;
+fVerbCnt = 0;
+fVerbs = NULL;
+fPoints = NULL;
+fFreeSpace = 0;
+fGenerationID = kEmptyGenID;
+fSegmentMask = 0;
+fIsOval = false;
+SkDEBUGCODE(fEditorsAttached = 0;)
+SkDEBUGCODE(this->validate();)
+}
+void copy(const SkPathRef& ref, int additionalReserveVerbs, int additionalReservePoints);
+// Return true if the computed bounds are finite.
+static bool ComputePtBounds(SkRect* bounds, const SkPathRef& ref) {
+int count = ref.countPoints();
+if (count <= 1) {  // we ignore just 1 point (moveto)
+bounds->setEmpty();
+return count ? ref.points()->isFinite() : true;
+} else {
+return bounds->setBoundsCheck(ref.points(), count);
+}
+}
+// called, if dirty, by getBounds()
+void computeBounds() const {
+SkDEBUGCODE(this->validate();)
+SkASSERT(fBoundsIsDirty);
+fIsFinite = ComputePtBounds(&fBounds, *this);
+fBoundsIsDirty = false;
+}
+void setBounds(const SkRect& rect) {
+SkASSERT(rect.fLeft <= rect.fRight && rect.fTop <= rect.fBottom);
+fBounds = rect;
+fBoundsIsDirty = false;
+fIsFinite = fBounds.isFinite();
+}
+/** Makes additional room but does not change the counts or change the genID */
+void incReserve(int additionalVerbs, int additionalPoints) {
+SkDEBUGCODE(this->validate();)
+size_t space = additionalVerbs * sizeof(uint8_t) + additionalPoints * sizeof (SkPoint);
+this->makeSpace(space);
+SkDEBUGCODE(this->validate();)
+}
+/** Resets the path ref with verbCount verbs and pointCount points, all uninitialized. Also
+*  allocates space for reserveVerb additional verbs and reservePoints additional points.*/
+void resetToSize(int verbCount, int pointCount, int conicCount,
+int reserveVerbs = 0, int reservePoints = 0) {
+SkDEBUGCODE(this->validate();)
+fBoundsIsDirty = true;      // this also invalidates fIsFinite
+fGenerationID = 0;
+fSegmentMask = 0;
+fIsOval = false;
+size_t newSize = sizeof(uint8_t) * verbCount + sizeof(SkPoint) * pointCount;
+size_t newReserve = sizeof(uint8_t) * reserveVerbs + sizeof(SkPoint) * reservePoints;
+size_t minSize = newSize + newReserve;
+ptrdiff_t sizeDelta = this->currSize() - minSize;
+if (sizeDelta < 0 || static_cast<size_t>(sizeDelta) >= 3 * minSize) {
+sk_free(fPoints);
+fPoints = NULL;
+fVerbs = NULL;
+fFreeSpace = 0;
+fVerbCnt = 0;
+fPointCnt = 0;
+this->makeSpace(minSize);
+fVerbCnt = verbCount;
+fPointCnt = pointCount;
+fFreeSpace -= newSize;
+} else {
+fPointCnt = pointCount;
+fVerbCnt = verbCount;
+fFreeSpace = this->currSize() - minSize;
+}
+fConicWeights.setCount(conicCount);
+SkDEBUGCODE(this->validate();)
+}
+/**
+* Increases the verb count by numVbs and point count by the required amount.
+* The new points are uninitialized. All the new verbs are set to the specified
+* verb. If 'verb' is kConic_Verb, 'weights' will return a pointer to the
+* uninitialized conic weights.
+*/
+SkPoint* growForRepeatedVerb(int /*SkPath::Verb*/ verb, int numVbs, SkScalar** weights);
+/**
+* Increases the verb count 1, records the new verb, and creates room for the requisite number
+* of additional points. A pointer to the first point is returned. Any new points are
+* uninitialized.
+*/
+SkPoint* growForVerb(int /*SkPath::Verb*/ verb, SkScalar weight);
+/**
+* Ensures that the free space available in the path ref is >= size. The verb and point counts
+* are not changed.
+*/
+void makeSpace(size_t size) {
+SkDEBUGCODE(this->validate();)
+ptrdiff_t growSize = size - fFreeSpace;
+if (growSize <= 0) {
+return;
+}
+size_t oldSize = this->currSize();
+// round to next multiple of 8 bytes
+growSize = (growSize + 7) & ~static_cast<size_t>(7);
+// we always at least double the allocation
+if (static_cast<size_t>(growSize) < oldSize) {
+growSize = oldSize;
+}
+if (growSize < kMinSize) {
+growSize = kMinSize;
+}
+size_t newSize = oldSize + growSize;
+// Note that realloc could memcpy more than we need. It seems to be a win anyway. TODO:
+// encapsulate this.
+fPoints = reinterpret_cast<SkPoint*>(sk_realloc_throw(fPoints, newSize));
+size_t oldVerbSize = fVerbCnt * sizeof(uint8_t);
+void* newVerbsDst = reinterpret_cast<void*>(
+reinterpret_cast<intptr_t>(fPoints) + newSize - oldVerbSize);
+void* oldVerbsSrc = reinterpret_cast<void*>(
+reinterpret_cast<intptr_t>(fPoints) + oldSize - oldVerbSize);
+memmove(newVerbsDst, oldVerbsSrc, oldVerbSize);
+fVerbs = reinterpret_cast<uint8_t*>(reinterpret_cast<intptr_t>(fPoints) + newSize);
+fFreeSpace += growSize;
+SkDEBUGCODE(this->validate();)
+}
+/**
+* Private, non-const-ptr version of the public function verbsMemBegin().
+*/
+uint8_t* verbsMemWritable() {
+SkDEBUGCODE(this->validate();)
+return fVerbs - fVerbCnt;
+}
+/**
+* Gets the total amount of space allocated for verbs, points, and reserve.
+*/
+size_t currSize() const {
+return reinterpret_cast<intptr_t>(fVerbs) - reinterpret_cast<intptr_t>(fPoints);
+}
+SkDEBUGCODE(void validate() const;)
+/**
+* Called the first time someone calls CreateEmpty to actually create the singleton.
+*/
+static void CreateEmptyImpl(int/*unused*/);
+void setIsOval(bool isOval) { fIsOval = isOval; }
+SkPoint* getPoints() {
+SkDEBUGCODE(this->validate();)
+fIsOval = false;
+return fPoints;
+}
+enum {
+kMinSize = 256,
+};
+mutable SkRect      fBounds;
+uint8_t             fSegmentMask;
+mutable uint8_t     fBoundsIsDirty;
+mutable SkBool8     fIsFinite;    // only meaningful if bounds are valid
+mutable SkBool8     fIsOval;
+SkPoint*            fPoints; // points to begining of the allocation
+uint8_t*            fVerbs; // points just past the end of the allocation (verbs grow backwards)
+int                 fVerbCnt;
+int                 fPointCnt;
+size_t              fFreeSpace; // redundant but saves computation
+SkTDArray<SkScalar> fConicWeights;
+enum {
+kEmptyGenID = 1, // GenID reserved for path ref with zero points and zero verbs.
+};
+mutable uint32_t    fGenerationID;
+SkDEBUGCODE(int32_t fEditorsAttached;) // assert that only one editor in use at any time.
+friend class PathRefTest_Private;
+typedef SkRefCnt INHERITED;
+};
+#endif

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comparison: gfx/skia/trunk/include/core/SkPathRef.h

gfx/skia/trunk/include/core/SkPathRef.h