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