• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 
2 /*
3  * Copyright 2012 Google Inc.
4  *
5  * Use of this source code is governed by a BSD-style license that can be
6  * found in the LICENSE file.
7  */
8 
9 #ifndef SkPathRef_DEFINED
10 #define SkPathRef_DEFINED
11 
12 #include "../private/SkAtomics.h"
13 #include "../private/SkTDArray.h"
14 #include "SkMatrix.h"
15 #include "SkPoint.h"
16 #include "SkRRect.h"
17 #include "SkRect.h"
18 #include "SkRefCnt.h"
19 #include "SkTemplates.h"
20 
21 class SkRBuffer;
22 class SkWBuffer;
23 
24 /**
25  * Holds the path verbs and points. It is versioned by a generation ID. None of its public methods
26  * modify the contents. To modify or append to the verbs/points wrap the SkPathRef in an
27  * SkPathRef::Editor object. Installing the editor resets the generation ID. It also performs
28  * copy-on-write if the SkPathRef is shared by multiple SkPaths. The caller passes the Editor's
29  * constructor a pointer to a sk_sp<SkPathRef>, which may be updated to point to a new SkPathRef
30  * after the editor's constructor returns.
31  *
32  * The points and verbs are stored in a single allocation. The points are at the begining of the
33  * allocation while the verbs are stored at end of the allocation, in reverse order. Thus the points
34  * and verbs both grow into the middle of the allocation until the meet. To access verb i in the
35  * verb array use ref.verbs()[~i] (because verbs() returns a pointer just beyond the first
36  * logical verb or the last verb in memory).
37  */
38 
39 class SK_API SkPathRef final : public SkNVRefCnt<SkPathRef> {
40 public:
41     class Editor {
42     public:
43         Editor(sk_sp<SkPathRef>* pathRef,
44                int incReserveVerbs = 0,
45                int incReservePoints = 0);
46 
~Editor()47         ~Editor() { SkDEBUGCODE(sk_atomic_dec(&fPathRef->fEditorsAttached);) }
48 
49         /**
50          * Returns the array of points.
51          */
points()52         SkPoint* points() { return fPathRef->getPoints(); }
points()53         const SkPoint* points() const { return fPathRef->points(); }
54 
55         /**
56          * Gets the ith point. Shortcut for this->points() + i
57          */
atPoint(int i)58         SkPoint* atPoint(int i) {
59             SkASSERT((unsigned) i < (unsigned) fPathRef->fPointCnt);
60             return this->points() + i;
61         }
atPoint(int i)62         const SkPoint* atPoint(int i) const {
63             SkASSERT((unsigned) i < (unsigned) fPathRef->fPointCnt);
64             return this->points() + i;
65         }
66 
67         /**
68          * Adds the verb and allocates space for the number of points indicated by the verb. The
69          * return value is a pointer to where the points for the verb should be written.
70          * 'weight' is only used if 'verb' is kConic_Verb
71          */
72         SkPoint* growForVerb(int /*SkPath::Verb*/ verb, SkScalar weight = 0) {
73             SkDEBUGCODE(fPathRef->validate();)
74             return fPathRef->growForVerb(verb, weight);
75         }
76 
77         /**
78          * Allocates space for multiple instances of a particular verb and the
79          * requisite points & weights.
80          * The return pointer points at the first new point (indexed normally [<i>]).
81          * If 'verb' is kConic_Verb, 'weights' will return a pointer to the
82          * space for the conic weights (indexed normally).
83          */
84         SkPoint* growForRepeatedVerb(int /*SkPath::Verb*/ verb,
85                                      int numVbs,
86                                      SkScalar** weights = nullptr) {
87             return fPathRef->growForRepeatedVerb(verb, numVbs, weights);
88         }
89 
90         /**
91          * Resets the path ref to a new verb and point count. The new verbs and points are
92          * uninitialized.
93          */
resetToSize(int newVerbCnt,int newPointCnt,int newConicCount)94         void resetToSize(int newVerbCnt, int newPointCnt, int newConicCount) {
95             fPathRef->resetToSize(newVerbCnt, newPointCnt, newConicCount);
96         }
97 
98         /**
99          * Gets the path ref that is wrapped in the Editor.
100          */
pathRef()101         SkPathRef* pathRef() { return fPathRef; }
102 
setIsOval(bool isOval,bool isCCW,unsigned start)103         void setIsOval(bool isOval, bool isCCW, unsigned start) {
104             fPathRef->setIsOval(isOval, isCCW, start);
105         }
106 
setIsRRect(bool isRRect,bool isCCW,unsigned start)107         void setIsRRect(bool isRRect, bool isCCW, unsigned start) {
108             fPathRef->setIsRRect(isRRect, isCCW, start);
109         }
110 
setBounds(const SkRect & rect)111         void setBounds(const SkRect& rect) { fPathRef->setBounds(rect); }
112 
113     private:
114         SkPathRef* fPathRef;
115     };
116 
117     class SK_API Iter {
118     public:
119         Iter();
120         Iter(const SkPathRef&);
121 
122         void setPathRef(const SkPathRef&);
123 
124         /** Return the next verb in this iteration of the path. When all
125             segments have been visited, return kDone_Verb.
126 
127             If any point in the path is non-finite, return kDone_Verb immediately.
128 
129             @param  pts The points representing the current verb and/or segment
130                         This must not be NULL.
131             @return The verb for the current segment
132         */
133         uint8_t next(SkPoint pts[4]);
134         uint8_t peek() const;
135 
conicWeight()136         SkScalar conicWeight() const { return *fConicWeights; }
137 
138     private:
139         const SkPoint*  fPts;
140         const uint8_t*  fVerbs;
141         const uint8_t*  fVerbStop;
142         const SkScalar* fConicWeights;
143     };
144 
145 public:
146     /**
147      * Gets a path ref with no verbs or points.
148      */
149     static SkPathRef* CreateEmpty();
150 
151     /**
152      *  Returns true if all of the points in this path are finite, meaning there
153      *  are no infinities and no NaNs.
154      */
isFinite()155     bool isFinite() const {
156         if (fBoundsIsDirty) {
157             this->computeBounds();
158         }
159         return SkToBool(fIsFinite);
160     }
161 
162     /**
163      *  Returns a mask, where each bit corresponding to a SegmentMask is
164      *  set if the path contains 1 or more segments of that type.
165      *  Returns 0 for an empty path (no segments).
166      */
getSegmentMasks()167     uint32_t getSegmentMasks() const { return fSegmentMask; }
168 
169     /** Returns true if the path is an oval.
170      *
171      * @param rect      returns the bounding rect of this oval. It's a circle
172      *                  if the height and width are the same.
173      * @param isCCW     is the oval CCW (or CW if false).
174      * @param start     indicates where the contour starts on the oval (see
175      *                  SkPath::addOval for intepretation of the index).
176      *
177      * @return true if this path is an oval.
178      *              Tracking whether a path is an oval is considered an
179      *              optimization for performance and so some paths that are in
180      *              fact ovals can report false.
181      */
isOval(SkRect * rect,bool * isCCW,unsigned * start)182     bool isOval(SkRect* rect, bool* isCCW, unsigned* start) const {
183         if (fIsOval) {
184             if (rect) {
185                 *rect = this->getBounds();
186             }
187             if (isCCW) {
188                 *isCCW = SkToBool(fRRectOrOvalIsCCW);
189             }
190             if (start) {
191                 *start = fRRectOrOvalStartIdx;
192             }
193         }
194 
195         return SkToBool(fIsOval);
196     }
197 
isRRect(SkRRect * rrect,bool * isCCW,unsigned * start)198     bool isRRect(SkRRect* rrect, bool* isCCW, unsigned* start) const {
199         if (fIsRRect) {
200             if (rrect) {
201                 *rrect = this->getRRect();
202             }
203             if (isCCW) {
204                 *isCCW = SkToBool(fRRectOrOvalIsCCW);
205             }
206             if (start) {
207                 *start = fRRectOrOvalStartIdx;
208             }
209         }
210         return SkToBool(fIsRRect);
211     }
212 
213 
hasComputedBounds()214     bool hasComputedBounds() const {
215         return !fBoundsIsDirty;
216     }
217 
218     /** Returns the bounds of the path's points. If the path contains 0 or 1
219         points, the bounds is set to (0,0,0,0), and isEmpty() will return true.
220         Note: this bounds may be larger than the actual shape, since curves
221         do not extend as far as their control points.
222     */
getBounds()223     const SkRect& getBounds() const {
224         if (fBoundsIsDirty) {
225             this->computeBounds();
226         }
227         return fBounds;
228     }
229 
230     SkRRect getRRect() const;
231 
232     /**
233      * Transforms a path ref by a matrix, allocating a new one only if necessary.
234      */
235     static void CreateTransformedCopy(sk_sp<SkPathRef>* dst,
236                                       const SkPathRef& src,
237                                       const SkMatrix& matrix);
238 
239     static SkPathRef* CreateFromBuffer(SkRBuffer* buffer);
240 
241     /**
242      * Rollsback a path ref to zero verbs and points with the assumption that the path ref will be
243      * repopulated with approximately the same number of verbs and points. A new path ref is created
244      * only if necessary.
245      */
246     static void Rewind(sk_sp<SkPathRef>* pathRef);
247 
248     ~SkPathRef();
countPoints()249     int countPoints() const { return fPointCnt; }
countVerbs()250     int countVerbs() const { return fVerbCnt; }
countWeights()251     int countWeights() const { return fConicWeights.count(); }
252 
253     /**
254      * Returns a pointer one beyond the first logical verb (last verb in memory order).
255      */
verbs()256     const uint8_t* verbs() const { return fVerbs; }
257 
258     /**
259      * Returns a const pointer to the first verb in memory (which is the last logical verb).
260      */
verbsMemBegin()261     const uint8_t* verbsMemBegin() const { return this->verbs() - fVerbCnt; }
262 
263     /**
264      * Returns a const pointer to the first point.
265      */
points()266     const SkPoint* points() const { return fPoints; }
267 
268     /**
269      * Shortcut for this->points() + this->countPoints()
270      */
pointsEnd()271     const SkPoint* pointsEnd() const { return this->points() + this->countPoints(); }
272 
conicWeights()273     const SkScalar* conicWeights() const { return fConicWeights.begin(); }
conicWeightsEnd()274     const SkScalar* conicWeightsEnd() const { return fConicWeights.end(); }
275 
276     /**
277      * Convenience methods for getting to a verb or point by index.
278      */
atVerb(int index)279     uint8_t atVerb(int index) const {
280         SkASSERT((unsigned) index < (unsigned) fVerbCnt);
281         return this->verbs()[~index];
282     }
atPoint(int index)283     const SkPoint& atPoint(int index) const {
284         SkASSERT((unsigned) index < (unsigned) fPointCnt);
285         return this->points()[index];
286     }
287 
288     bool operator== (const SkPathRef& ref) const;
289 
290     /**
291      * Writes the path points and verbs to a buffer.
292      */
293     void writeToBuffer(SkWBuffer* buffer) const;
294 
295     /**
296      * Gets the number of bytes that would be written in writeBuffer()
297      */
298     uint32_t writeSize() const;
299 
300     void interpolate(const SkPathRef& ending, SkScalar weight, SkPathRef* out) const;
301 
302     /**
303      * Gets an ID that uniquely identifies the contents of the path ref. If two path refs have the
304      * same ID then they have the same verbs and points. However, two path refs may have the same
305      * contents but different genIDs.
306      */
307     uint32_t genID() const;
308 
309     struct GenIDChangeListener {
~GenIDChangeListenerGenIDChangeListener310         virtual ~GenIDChangeListener() {}
311         virtual void onChange() = 0;
312     };
313 
314     void addGenIDChangeListener(GenIDChangeListener* listener);
315 
316     bool isValid() const;
317     SkDEBUGCODE(void validate() const { SkASSERT(this->isValid()); } )
318 
319 private:
320     enum SerializationOffsets {
321         kLegacyRRectOrOvalStartIdx_SerializationShift = 28, // requires 3 bits, ignored.
322         kLegacyRRectOrOvalIsCCW_SerializationShift = 27,    // requires 1 bit, ignored.
323         kLegacyIsRRect_SerializationShift = 26,             // requires 1 bit, ignored.
324         kIsFinite_SerializationShift = 25,                  // requires 1 bit
325         kLegacyIsOval_SerializationShift = 24,              // requires 1 bit, ignored.
326         kSegmentMask_SerializationShift = 0                 // requires 4 bits
327     };
328 
SkPathRef()329     SkPathRef() {
330         fBoundsIsDirty = true;    // this also invalidates fIsFinite
331         fPointCnt = 0;
332         fVerbCnt = 0;
333         fVerbs = nullptr;
334         fPoints = nullptr;
335         fFreeSpace = 0;
336         fGenerationID = kEmptyGenID;
337         fSegmentMask = 0;
338         fIsOval = false;
339         fIsRRect = false;
340         // The next two values don't matter unless fIsOval or fIsRRect are true.
341         fRRectOrOvalIsCCW = false;
342         fRRectOrOvalStartIdx = 0xAC;
343         SkDEBUGCODE(fEditorsAttached = 0;)
344         SkDEBUGCODE(this->validate();)
345     }
346 
347     void copy(const SkPathRef& ref, int additionalReserveVerbs, int additionalReservePoints);
348 
349     // Return true if the computed bounds are finite.
ComputePtBounds(SkRect * bounds,const SkPathRef & ref)350     static bool ComputePtBounds(SkRect* bounds, const SkPathRef& ref) {
351         return bounds->setBoundsCheck(ref.points(), ref.countPoints());
352     }
353 
354     // called, if dirty, by getBounds()
computeBounds()355     void computeBounds() const {
356         SkDEBUGCODE(this->validate();)
357         // TODO(mtklein): remove fBoundsIsDirty and fIsFinite,
358         // using an inverted rect instead of fBoundsIsDirty and always recalculating fIsFinite.
359         SkASSERT(fBoundsIsDirty);
360 
361         fIsFinite = ComputePtBounds(&fBounds, *this);
362         fBoundsIsDirty = false;
363     }
364 
setBounds(const SkRect & rect)365     void setBounds(const SkRect& rect) {
366         SkASSERT(rect.fLeft <= rect.fRight && rect.fTop <= rect.fBottom);
367         fBounds = rect;
368         fBoundsIsDirty = false;
369         fIsFinite = fBounds.isFinite();
370     }
371 
372     /** Makes additional room but does not change the counts or change the genID */
incReserve(int additionalVerbs,int additionalPoints)373     void incReserve(int additionalVerbs, int additionalPoints) {
374         SkDEBUGCODE(this->validate();)
375         size_t space = additionalVerbs * sizeof(uint8_t) + additionalPoints * sizeof (SkPoint);
376         this->makeSpace(space);
377         SkDEBUGCODE(this->validate();)
378     }
379 
380     /** Resets the path ref with verbCount verbs and pointCount points, all uninitialized. Also
381      *  allocates space for reserveVerb additional verbs and reservePoints additional points.*/
382     void resetToSize(int verbCount, int pointCount, int conicCount,
383                      int reserveVerbs = 0, int reservePoints = 0) {
384         SkDEBUGCODE(this->validate();)
385         fBoundsIsDirty = true;      // this also invalidates fIsFinite
386         fGenerationID = 0;
387 
388         fSegmentMask = 0;
389         fIsOval = false;
390         fIsRRect = false;
391 
392         size_t newSize = sizeof(uint8_t) * verbCount + sizeof(SkPoint) * pointCount;
393         size_t newReserve = sizeof(uint8_t) * reserveVerbs + sizeof(SkPoint) * reservePoints;
394         size_t minSize = newSize + newReserve;
395 
396         ptrdiff_t sizeDelta = this->currSize() - minSize;
397 
398         if (sizeDelta < 0 || static_cast<size_t>(sizeDelta) >= 3 * minSize) {
399             sk_free(fPoints);
400             fPoints = nullptr;
401             fVerbs = nullptr;
402             fFreeSpace = 0;
403             fVerbCnt = 0;
404             fPointCnt = 0;
405             this->makeSpace(minSize);
406             fVerbCnt = verbCount;
407             fPointCnt = pointCount;
408             fFreeSpace -= newSize;
409         } else {
410             fPointCnt = pointCount;
411             fVerbCnt = verbCount;
412             fFreeSpace = this->currSize() - minSize;
413         }
414         fConicWeights.setCount(conicCount);
415         SkDEBUGCODE(this->validate();)
416     }
417 
418     /**
419      * Increases the verb count by numVbs and point count by the required amount.
420      * The new points are uninitialized. All the new verbs are set to the specified
421      * verb. If 'verb' is kConic_Verb, 'weights' will return a pointer to the
422      * uninitialized conic weights.
423      */
424     SkPoint* growForRepeatedVerb(int /*SkPath::Verb*/ verb, int numVbs, SkScalar** weights);
425 
426     /**
427      * Increases the verb count 1, records the new verb, and creates room for the requisite number
428      * of additional points. A pointer to the first point is returned. Any new points are
429      * uninitialized.
430      */
431     SkPoint* growForVerb(int /*SkPath::Verb*/ verb, SkScalar weight);
432 
433     /**
434      * Ensures that the free space available in the path ref is >= size. The verb and point counts
435      * are not changed.
436      */
makeSpace(size_t size)437     void makeSpace(size_t size) {
438         SkDEBUGCODE(this->validate();)
439         if (size <= fFreeSpace) {
440             return;
441         }
442         size_t growSize = size - fFreeSpace;
443         size_t oldSize = this->currSize();
444         // round to next multiple of 8 bytes
445         growSize = (growSize + 7) & ~static_cast<size_t>(7);
446         // we always at least double the allocation
447         if (growSize < oldSize) {
448             growSize = oldSize;
449         }
450         if (growSize < kMinSize) {
451             growSize = kMinSize;
452         }
453         constexpr size_t maxSize = std::numeric_limits<size_t>::max();
454         size_t newSize;
455         if (growSize <= maxSize - oldSize) {
456             newSize = oldSize + growSize;
457         } else {
458             SK_ABORT("Path too big.");
459         }
460         // Note that realloc could memcpy more than we need. It seems to be a win anyway. TODO:
461         // encapsulate this.
462         fPoints = reinterpret_cast<SkPoint*>(sk_realloc_throw(fPoints, newSize));
463         size_t oldVerbSize = fVerbCnt * sizeof(uint8_t);
464         void* newVerbsDst = SkTAddOffset<void>(fPoints, newSize - oldVerbSize);
465         void* oldVerbsSrc = SkTAddOffset<void>(fPoints, oldSize - oldVerbSize);
466         memmove(newVerbsDst, oldVerbsSrc, oldVerbSize);
467         fVerbs = SkTAddOffset<uint8_t>(fPoints, newSize);
468         fFreeSpace += growSize;
469         SkDEBUGCODE(this->validate();)
470     }
471 
472     /**
473      * Private, non-const-ptr version of the public function verbsMemBegin().
474      */
verbsMemWritable()475     uint8_t* verbsMemWritable() {
476         SkDEBUGCODE(this->validate();)
477         return fVerbs - fVerbCnt;
478     }
479 
480     /**
481      * Gets the total amount of space allocated for verbs, points, and reserve.
482      */
currSize()483     size_t currSize() const {
484         return reinterpret_cast<intptr_t>(fVerbs) - reinterpret_cast<intptr_t>(fPoints);
485     }
486 
487     /**
488      * Called the first time someone calls CreateEmpty to actually create the singleton.
489      */
490     friend SkPathRef* sk_create_empty_pathref();
491 
setIsOval(bool isOval,bool isCCW,unsigned start)492     void setIsOval(bool isOval, bool isCCW, unsigned start) {
493         fIsOval = isOval;
494         fRRectOrOvalIsCCW = isCCW;
495         fRRectOrOvalStartIdx = start;
496     }
497 
setIsRRect(bool isRRect,bool isCCW,unsigned start)498     void setIsRRect(bool isRRect, bool isCCW, unsigned start) {
499         fIsRRect = isRRect;
500         fRRectOrOvalIsCCW = isCCW;
501         fRRectOrOvalStartIdx = start;
502     }
503 
504     // called only by the editor. Note that this is not a const function.
getPoints()505     SkPoint* getPoints() {
506         SkDEBUGCODE(this->validate();)
507         fIsOval = false;
508         fIsRRect = false;
509         return fPoints;
510     }
511 
getPoints()512     const SkPoint* getPoints() const {
513         SkDEBUGCODE(this->validate();)
514         return fPoints;
515     }
516 
517     void callGenIDChangeListeners();
518 
519     enum {
520         kMinSize = 256,
521     };
522 
523     mutable SkRect   fBounds;
524 
525     SkPoint*            fPoints; // points to begining of the allocation
526     uint8_t*            fVerbs; // points just past the end of the allocation (verbs grow backwards)
527     int                 fVerbCnt;
528     int                 fPointCnt;
529     size_t              fFreeSpace; // redundant but saves computation
530     SkTDArray<SkScalar> fConicWeights;
531 
532     enum {
533         kEmptyGenID = 1, // GenID reserved for path ref with zero points and zero verbs.
534     };
535     mutable uint32_t    fGenerationID;
536     SkDEBUGCODE(int32_t fEditorsAttached;) // assert that only one editor in use at any time.
537 
538     SkTDArray<GenIDChangeListener*> fGenIDChangeListeners;  // pointers are owned
539 
540     mutable uint8_t  fBoundsIsDirty;
541     mutable SkBool8  fIsFinite;    // only meaningful if bounds are valid
542 
543     SkBool8  fIsOval;
544     SkBool8  fIsRRect;
545     // Both the circle and rrect special cases have a notion of direction and starting point
546     // The next two variables store that information for either.
547     SkBool8  fRRectOrOvalIsCCW;
548     uint8_t  fRRectOrOvalStartIdx;
549     uint8_t  fSegmentMask;
550 
551     friend class PathRefTest_Private;
552     friend class ForceIsRRect_Private; // unit test isRRect
553 };
554 
555 #endif
556