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1 
2 /*
3  * Copyright 2006 The Android Open Source Project
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 
10 #ifndef SkPath_DEFINED
11 #define SkPath_DEFINED
12 
13 #include "SkInstCnt.h"
14 #include "SkMatrix.h"
15 #include "SkPathRef.h"
16 #include "SkTDArray.h"
17 #include "SkRefCnt.h"
18 
19 class SkReader32;
20 class SkWriter32;
21 class SkAutoPathBoundsUpdate;
22 class SkString;
23 class SkRRect;
24 
25 /** \class SkPath
26 
27     The SkPath class encapsulates compound (multiple contour) geometric paths
28     consisting of straight line segments, quadratic curves, and cubic curves.
29 */
30 class SK_API SkPath {
31 public:
32     SK_DECLARE_INST_COUNT_ROOT(SkPath);
33 
34     SkPath();
35     SkPath(const SkPath&);
36     ~SkPath();
37 
38     SkPath& operator=(const SkPath&);
39     friend  SK_API bool operator==(const SkPath&, const SkPath&);
40     friend bool operator!=(const SkPath& a, const SkPath& b) {
41         return !(a == b);
42     }
43 
44     enum FillType {
45         /** Specifies that "inside" is computed by a non-zero sum of signed
46             edge crossings
47         */
48         kWinding_FillType,
49         /** Specifies that "inside" is computed by an odd number of edge
50             crossings
51         */
52         kEvenOdd_FillType,
53         /** Same as Winding, but draws outside of the path, rather than inside
54         */
55         kInverseWinding_FillType,
56         /** Same as EvenOdd, but draws outside of the path, rather than inside
57          */
58         kInverseEvenOdd_FillType
59     };
60 
61     /** Return the path's fill type. This is used to define how "inside" is
62         computed. The default value is kWinding_FillType.
63 
64         @return the path's fill type
65     */
getFillType()66     FillType getFillType() const { return (FillType)fFillType; }
67 
68     /** Set the path's fill type. This is used to define how "inside" is
69         computed. The default value is kWinding_FillType.
70 
71         @param ft The new fill type for this path
72     */
setFillType(FillType ft)73     void setFillType(FillType ft) {
74         fFillType = SkToU8(ft);
75     }
76 
77     /** Returns true if the filltype is one of the Inverse variants */
isInverseFillType()78     bool isInverseFillType() const { return IsInverseFillType((FillType)fFillType); }
79 
80     /**
81      *  Toggle between inverse and normal filltypes. This reverse the return
82      *  value of isInverseFillType()
83      */
toggleInverseFillType()84     void toggleInverseFillType() {
85         fFillType ^= 2;
86     }
87 
88     enum Convexity {
89         kUnknown_Convexity,
90         kConvex_Convexity,
91         kConcave_Convexity
92     };
93 
94     /**
95      *  Return the path's convexity, as stored in the path. If it is currently unknown,
96      *  then this function will attempt to compute the convexity (and cache the result).
97      */
getConvexity()98     Convexity getConvexity() const {
99         if (kUnknown_Convexity != fConvexity) {
100             return static_cast<Convexity>(fConvexity);
101         } else {
102             return this->internalGetConvexity();
103         }
104     }
105 
106     /**
107      *  Return the currently cached value for convexity, even if that is set to
108      *  kUnknown_Convexity. Note: getConvexity() will automatically call
109      *  ComputeConvexity and cache its return value if the current setting is
110      *  kUnknown.
111      */
getConvexityOrUnknown()112     Convexity getConvexityOrUnknown() const { return (Convexity)fConvexity; }
113 
114     /**
115      *  Store a convexity setting in the path. There is no automatic check to
116      *  see if this value actually agrees with the return value that would be
117      *  computed by getConvexity().
118      *
119      *  Note: even if this is set to a "known" value, if the path is later
120      *  changed (e.g. lineTo(), addRect(), etc.) then the cached value will be
121      *  reset to kUnknown_Convexity.
122      */
123     void setConvexity(Convexity);
124 
125     /**
126      *  Returns true if the path is flagged as being convex. This is not a
127      *  confirmed by any analysis, it is just the value set earlier.
128      */
isConvex()129     bool isConvex() const {
130         return kConvex_Convexity == this->getConvexity();
131     }
132 
133     /**
134      *  Set the isConvex flag to true or false. Convex paths may draw faster if
135      *  this flag is set, though setting this to true on a path that is in fact
136      *  not convex can give undefined results when drawn. Paths default to
137      *  isConvex == false
138      */
139     SK_ATTR_DEPRECATED("use setConvexity")
setIsConvex(bool isConvex)140     void setIsConvex(bool isConvex) {
141         this->setConvexity(isConvex ? kConvex_Convexity : kConcave_Convexity);
142     }
143 
144     /** Returns true if the path is an oval.
145      *
146      * @param rect      returns the bounding rect of this oval. It's a circle
147      *                  if the height and width are the same.
148      *
149      * @return true if this path is an oval.
150      *              Tracking whether a path is an oval is considered an
151      *              optimization for performance and so some paths that are in
152      *              fact ovals can report false.
153      */
isOval(SkRect * rect)154     bool isOval(SkRect* rect) const { return fPathRef->isOval(rect); }
155 
156     /** Clear any lines and curves from the path, making it empty. This frees up
157         internal storage associated with those segments.
158         On Android, does not change fSourcePath.
159     */
160     void reset();
161 
162     /** Similar to reset(), in that all lines and curves are removed from the
163         path. However, any internal storage for those lines/curves is retained,
164         making reuse of the path potentially faster.
165         On Android, does not change fSourcePath.
166     */
167     void rewind();
168 
169     /** Returns true if the path is empty (contains no lines or curves)
170 
171         @return true if the path is empty (contains no lines or curves)
172     */
isEmpty()173     bool isEmpty() const {
174         SkDEBUGCODE(this->validate();)
175         return 0 == fPathRef->countVerbs();
176     }
177 
178     /**
179      *  Returns true if all of the points in this path are finite, meaning there
180      *  are no infinities and no NaNs.
181      */
isFinite()182     bool isFinite() const {
183         SkDEBUGCODE(this->validate();)
184         return fPathRef->isFinite();
185     }
186 
187     /** Test a line for zero length
188 
189         @return true if the line is of zero length; otherwise false.
190     */
IsLineDegenerate(const SkPoint & p1,const SkPoint & p2)191     static bool IsLineDegenerate(const SkPoint& p1, const SkPoint& p2) {
192         return p1.equalsWithinTolerance(p2);
193     }
194 
195     /** Test a quad for zero length
196 
197         @return true if the quad is of zero length; otherwise false.
198     */
IsQuadDegenerate(const SkPoint & p1,const SkPoint & p2,const SkPoint & p3)199     static bool IsQuadDegenerate(const SkPoint& p1, const SkPoint& p2,
200                                  const SkPoint& p3) {
201         return p1.equalsWithinTolerance(p2) &&
202                p2.equalsWithinTolerance(p3);
203     }
204 
205     /** Test a cubic curve for zero length
206 
207         @return true if the cubic is of zero length; otherwise false.
208     */
IsCubicDegenerate(const SkPoint & p1,const SkPoint & p2,const SkPoint & p3,const SkPoint & p4)209     static bool IsCubicDegenerate(const SkPoint& p1, const SkPoint& p2,
210                                   const SkPoint& p3, const SkPoint& p4) {
211         return p1.equalsWithinTolerance(p2) &&
212                p2.equalsWithinTolerance(p3) &&
213                p3.equalsWithinTolerance(p4);
214     }
215 
216     /**
217      *  Returns true if the path specifies a single line (i.e. it contains just
218      *  a moveTo and a lineTo). If so, and line[] is not null, it sets the 2
219      *  points in line[] to the end-points of the line. If the path is not a
220      *  line, returns false and ignores line[].
221      */
222     bool isLine(SkPoint line[2]) const;
223 
224     /** Returns true if the path specifies a rectangle. If so, and if rect is
225         not null, set rect to the bounds of the path. If the path does not
226         specify a rectangle, return false and ignore rect.
227 
228         @param rect If not null, returns the bounds of the path if it specifies
229                     a rectangle
230         @return true if the path specifies a rectangle
231     */
232     bool isRect(SkRect* rect) const;
233 
234     /** Return the number of points in the path
235      */
236     int countPoints() const;
237 
238     /** Return the point at the specified index. If the index is out of range
239          (i.e. is not 0 <= index < countPoints()) then the returned coordinates
240          will be (0,0)
241      */
242     SkPoint getPoint(int index) const;
243 
244     /** Returns the number of points in the path. Up to max points are copied.
245 
246         @param points If not null, receives up to max points
247         @param max The maximum number of points to copy into points
248         @return the actual number of points in the path
249     */
250     int getPoints(SkPoint points[], int max) const;
251 
252     /** Return the number of verbs in the path
253      */
254     int countVerbs() const;
255 
256     /** Returns the number of verbs in the path. Up to max verbs are copied. The
257         verbs are copied as one byte per verb.
258 
259         @param verbs If not null, receives up to max verbs
260         @param max The maximum number of verbs to copy into verbs
261         @return the actual number of verbs in the path
262     */
263     int getVerbs(uint8_t verbs[], int max) const;
264 
265     //! Swap contents of this and other. Guaranteed not to throw
266     void swap(SkPath& other);
267 
268     /** Returns the bounds of the path's points. If the path contains 0 or 1
269         points, the bounds is set to (0,0,0,0), and isEmpty() will return true.
270         Note: this bounds may be larger than the actual shape, since curves
271         do not extend as far as their control points.
272     */
getBounds()273     const SkRect& getBounds() const {
274         return fPathRef->getBounds();
275     }
276 
277     /** Calling this will, if the internal cache of the bounds is out of date,
278         update it so that subsequent calls to getBounds will be instantaneous.
279         This also means that any copies or simple transformations of the path
280         will inherit the cached bounds.
281      */
updateBoundsCache()282     void updateBoundsCache() const {
283         // for now, just calling getBounds() is sufficient
284         this->getBounds();
285     }
286 
287     /**
288      * Does a conservative test to see whether a rectangle is inside a path. Currently it only
289      * will ever return true for single convex contour paths. The empty-status of the rect is not
290      * considered (e.g. a rect that is a point can be inside a path). Points or line segments where
291      * the rect edge touches the path border are not considered containment violations.
292      */
293     bool conservativelyContainsRect(const SkRect& rect) const;
294 
295     //  Construction methods
296 
297     /** Hint to the path to prepare for adding more points. This can allow the
298         path to more efficiently grow its storage.
299 
300         @param extraPtCount The number of extra points the path should
301                             preallocate for.
302     */
303     void incReserve(unsigned extraPtCount);
304 
305     /** Set the beginning of the next contour to the point (x,y).
306 
307         @param x    The x-coordinate of the start of a new contour
308         @param y    The y-coordinate of the start of a new contour
309     */
310     void moveTo(SkScalar x, SkScalar y);
311 
312     /** Set the beginning of the next contour to the point
313 
314         @param p    The start of a new contour
315     */
moveTo(const SkPoint & p)316     void moveTo(const SkPoint& p) {
317         this->moveTo(p.fX, p.fY);
318     }
319 
320     /** Set the beginning of the next contour relative to the last point on the
321         previous contour. If there is no previous contour, this is treated the
322         same as moveTo().
323 
324         @param dx   The amount to add to the x-coordinate of the end of the
325                     previous contour, to specify the start of a new contour
326         @param dy   The amount to add to the y-coordinate of the end of the
327                     previous contour, to specify the start of a new contour
328     */
329     void rMoveTo(SkScalar dx, SkScalar dy);
330 
331     /** Add a line from the last point to the specified point (x,y). If no
332         moveTo() call has been made for this contour, the first point is
333         automatically set to (0,0).
334 
335         @param x    The x-coordinate of the end of a line
336         @param y    The y-coordinate of the end of a line
337     */
338     void lineTo(SkScalar x, SkScalar y);
339 
340     /** Add a line from the last point to the specified point. If no moveTo()
341         call has been made for this contour, the first point is automatically
342         set to (0,0).
343 
344         @param p    The end of a line
345     */
lineTo(const SkPoint & p)346     void lineTo(const SkPoint& p) {
347         this->lineTo(p.fX, p.fY);
348     }
349 
350     /** Same as lineTo, but the coordinates are considered relative to the last
351         point on this contour. If there is no previous point, then a moveTo(0,0)
352         is inserted automatically.
353 
354         @param dx   The amount to add to the x-coordinate of the previous point
355                     on this contour, to specify a line
356         @param dy   The amount to add to the y-coordinate of the previous point
357                     on this contour, to specify a line
358     */
359     void rLineTo(SkScalar dx, SkScalar dy);
360 
361     /** Add a quadratic bezier from the last point, approaching control point
362         (x1,y1), and ending at (x2,y2). If no moveTo() call has been made for
363         this contour, the first point is automatically set to (0,0).
364 
365         @param x1   The x-coordinate of the control point on a quadratic curve
366         @param y1   The y-coordinate of the control point on a quadratic curve
367         @param x2   The x-coordinate of the end point on a quadratic curve
368         @param y2   The y-coordinate of the end point on a quadratic curve
369     */
370     void quadTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2);
371 
372     /** Add a quadratic bezier from the last point, approaching control point
373         p1, and ending at p2. If no moveTo() call has been made for this
374         contour, the first point is automatically set to (0,0).
375 
376         @param p1   The control point on a quadratic curve
377         @param p2   The end point on a quadratic curve
378     */
quadTo(const SkPoint & p1,const SkPoint & p2)379     void quadTo(const SkPoint& p1, const SkPoint& p2) {
380         this->quadTo(p1.fX, p1.fY, p2.fX, p2.fY);
381     }
382 
383     /** Same as quadTo, but the coordinates are considered relative to the last
384         point on this contour. If there is no previous point, then a moveTo(0,0)
385         is inserted automatically.
386 
387         @param dx1   The amount to add to the x-coordinate of the last point on
388                 this contour, to specify the control point of a quadratic curve
389         @param dy1   The amount to add to the y-coordinate of the last point on
390                 this contour, to specify the control point of a quadratic curve
391         @param dx2   The amount to add to the x-coordinate of the last point on
392                      this contour, to specify the end point of a quadratic curve
393         @param dy2   The amount to add to the y-coordinate of the last point on
394                      this contour, to specify the end point of a quadratic curve
395     */
396     void rQuadTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2);
397 
398     void conicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
399                  SkScalar w);
conicTo(const SkPoint & p1,const SkPoint & p2,SkScalar w)400     void conicTo(const SkPoint& p1, const SkPoint& p2, SkScalar w) {
401         this->conicTo(p1.fX, p1.fY, p2.fX, p2.fY, w);
402     }
403     void rConicTo(SkScalar dx1, SkScalar dy1, SkScalar dx2, SkScalar dy2,
404                   SkScalar w);
405 
406     /** Add a cubic bezier from the last point, approaching control points
407         (x1,y1) and (x2,y2), and ending at (x3,y3). If no moveTo() call has been
408         made for this contour, the first point is automatically set to (0,0).
409 
410         @param x1   The x-coordinate of the 1st control point on a cubic curve
411         @param y1   The y-coordinate of the 1st control point on a cubic curve
412         @param x2   The x-coordinate of the 2nd control point on a cubic curve
413         @param y2   The y-coordinate of the 2nd control point on a cubic curve
414         @param x3   The x-coordinate of the end point on a cubic curve
415         @param y3   The y-coordinate of the end point on a cubic curve
416     */
417     void cubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
418                  SkScalar x3, SkScalar y3);
419 
420     /** Add a cubic bezier from the last point, approaching control points p1
421         and p2, and ending at p3. If no moveTo() call has been made for this
422         contour, the first point is automatically set to (0,0).
423 
424         @param p1   The 1st control point on a cubic curve
425         @param p2   The 2nd control point on a cubic curve
426         @param p3   The end point on a cubic curve
427     */
cubicTo(const SkPoint & p1,const SkPoint & p2,const SkPoint & p3)428     void cubicTo(const SkPoint& p1, const SkPoint& p2, const SkPoint& p3) {
429         this->cubicTo(p1.fX, p1.fY, p2.fX, p2.fY, p3.fX, p3.fY);
430     }
431 
432     /** Same as cubicTo, but the coordinates are considered relative to the
433         current point on this contour. If there is no previous point, then a
434         moveTo(0,0) is inserted automatically.
435 
436         @param dx1   The amount to add to the x-coordinate of the last point on
437                 this contour, to specify the 1st control point of a cubic curve
438         @param dy1   The amount to add to the y-coordinate of the last point on
439                 this contour, to specify the 1st control point of a cubic curve
440         @param dx2   The amount to add to the x-coordinate of the last point on
441                 this contour, to specify the 2nd control point of a cubic curve
442         @param dy2   The amount to add to the y-coordinate of the last point on
443                 this contour, to specify the 2nd control point of a cubic curve
444         @param dx3   The amount to add to the x-coordinate of the last point on
445                      this contour, to specify the end point of a cubic curve
446         @param dy3   The amount to add to the y-coordinate of the last point on
447                      this contour, to specify the end point of a cubic curve
448     */
449     void rCubicTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
450                   SkScalar x3, SkScalar y3);
451 
452     /** Append the specified arc to the path as a new contour. If the start of
453         the path is different from the path's current last point, then an
454         automatic lineTo() is added to connect the current contour to the start
455         of the arc. However, if the path is empty, then we call moveTo() with
456         the first point of the arc. The sweep angle is treated mod 360.
457 
458         @param oval The bounding oval defining the shape and size of the arc
459         @param startAngle Starting angle (in degrees) where the arc begins
460         @param sweepAngle Sweep angle (in degrees) measured clockwise. This is
461                           treated mod 360.
462         @param forceMoveTo If true, always begin a new contour with the arc
463     */
464     void arcTo(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle,
465                bool forceMoveTo);
466 
467     /** Append a line and arc to the current path. This is the same as the
468         PostScript call "arct".
469     */
470     void arcTo(SkScalar x1, SkScalar y1, SkScalar x2, SkScalar y2,
471                SkScalar radius);
472 
473     /** Append a line and arc to the current path. This is the same as the
474         PostScript call "arct".
475     */
arcTo(const SkPoint p1,const SkPoint p2,SkScalar radius)476     void arcTo(const SkPoint p1, const SkPoint p2, SkScalar radius) {
477         this->arcTo(p1.fX, p1.fY, p2.fX, p2.fY, radius);
478     }
479 
480     /** Close the current contour. If the current point is not equal to the
481         first point of the contour, a line segment is automatically added.
482     */
483     void close();
484 
485     enum Direction {
486         /** Direction either has not been or could not be computed */
487         kUnknown_Direction,
488         /** clockwise direction for adding closed contours */
489         kCW_Direction,
490         /** counter-clockwise direction for adding closed contours */
491         kCCW_Direction,
492     };
493 
494     /**
495      *  Return the opposite of the specified direction. kUnknown is its own
496      *  opposite.
497      */
OppositeDirection(Direction dir)498     static Direction OppositeDirection(Direction dir) {
499         static const Direction gOppositeDir[] = {
500             kUnknown_Direction, kCCW_Direction, kCW_Direction
501         };
502         return gOppositeDir[dir];
503     }
504 
505     /**
506      *  Returns whether or not a fill type is inverted
507      *
508      *  kWinding_FillType        -> false
509      *  kEvenOdd_FillType        -> false
510      *  kInverseWinding_FillType -> true
511      *  kInverseEvenOdd_FillType -> true
512      */
IsInverseFillType(FillType fill)513     static bool IsInverseFillType(FillType fill) {
514         SK_COMPILE_ASSERT(0 == kWinding_FillType, fill_type_mismatch);
515         SK_COMPILE_ASSERT(1 == kEvenOdd_FillType, fill_type_mismatch);
516         SK_COMPILE_ASSERT(2 == kInverseWinding_FillType, fill_type_mismatch);
517         SK_COMPILE_ASSERT(3 == kInverseEvenOdd_FillType, fill_type_mismatch);
518         return (fill & 2) != 0;
519     }
520 
521     /**
522      *  Returns the equivalent non-inverted fill type to the given fill type
523      *
524      *  kWinding_FillType        -> kWinding_FillType
525      *  kEvenOdd_FillType        -> kEvenOdd_FillType
526      *  kInverseWinding_FillType -> kWinding_FillType
527      *  kInverseEvenOdd_FillType -> kEvenOdd_FillType
528      */
ConvertToNonInverseFillType(FillType fill)529     static FillType ConvertToNonInverseFillType(FillType fill) {
530         SK_COMPILE_ASSERT(0 == kWinding_FillType, fill_type_mismatch);
531         SK_COMPILE_ASSERT(1 == kEvenOdd_FillType, fill_type_mismatch);
532         SK_COMPILE_ASSERT(2 == kInverseWinding_FillType, fill_type_mismatch);
533         SK_COMPILE_ASSERT(3 == kInverseEvenOdd_FillType, fill_type_mismatch);
534         return (FillType)(fill & 1);
535     }
536 
537     /**
538      *  Tries to quickly compute the direction of the first non-degenerate
539      *  contour. If it can be computed, return true and set dir to that
540      *  direction. If it cannot be (quickly) determined, return false and ignore
541      *  the dir parameter. If the direction was determined, it is cached to make
542      *  subsequent calls return quickly.
543      */
544     bool cheapComputeDirection(Direction* dir) const;
545 
546     /**
547      *  Returns true if the path's direction can be computed via
548      *  cheapComputDirection() and if that computed direction matches the
549      *  specified direction. If dir is kUnknown, returns true if the direction
550      *  cannot be computed.
551      */
cheapIsDirection(Direction dir)552     bool cheapIsDirection(Direction dir) const {
553         Direction computedDir = kUnknown_Direction;
554         (void)this->cheapComputeDirection(&computedDir);
555         return computedDir == dir;
556     }
557 
558     enum PathAsRect {
559         /** The path can not draw the same as its bounds. */
560         kNone_PathAsRect,
561         /** The path draws the same as its bounds when filled. */
562         kFill_PathAsRect,
563         /** The path draws the same as its bounds when stroked or filled. */
564         kStroke_PathAsRect,
565     };
566 
567     /** Returns kFill_PathAsRect or kStroke_PathAsRect if drawing the path (either filled or
568         stroked) will be equivalent to filling/stroking the path's bounding rect. If
569         either is true, and direction is not null, sets the direction of the contour. If the
570         path is not drawn equivalent to a rect, returns kNone_PathAsRect and ignores direction.
571 
572         @param direction If not null, set to the contour's direction when it is drawn as a rect
573         @return the path's PathAsRect type
574      */
575     PathAsRect asRect(Direction* direction = NULL) const;
576 
577     /** Returns true if the path specifies a rectangle. If so, and if isClosed is
578         not null, set isClosed to true if the path is closed. Also, if returning true
579         and direction is not null, return the rect direction. If the path does not
580         specify a rectangle, return false and ignore isClosed and direction.
581 
582         @param isClosed If not null, set to true if the path is closed
583         @param direction If not null, set to the rectangle's direction
584         @return true if the path specifies a rectangle
585     */
586     bool isRect(bool* isClosed, Direction* direction) const;
587 
588     /** Returns true if the path specifies a pair of nested rectangles. If so, and if
589         rect is not null, set rect[0] to the outer rectangle and rect[1] to the inner
590         rectangle. If so, and dirs is not null, set dirs[0] to the direction of
591         the outer rectangle and dirs[1] to the direction of the inner rectangle. If
592         the path does not specify a pair of nested rectangles, return
593         false and ignore rect and dirs.
594 
595         @param rect If not null, returns the path as a pair of nested rectangles
596         @param dirs If not null, returns the direction of the rects
597         @return true if the path describes a pair of nested rectangles
598     */
599     bool isNestedRects(SkRect rect[2], Direction dirs[2] = NULL) const;
600 
601     /**
602      *  Add a closed rectangle contour to the path
603      *  @param rect The rectangle to add as a closed contour to the path
604      *  @param dir  The direction to wind the rectangle's contour. Cannot be
605      *              kUnknown_Direction.
606      */
607     void addRect(const SkRect& rect, Direction dir = kCW_Direction);
608 
609     /**
610      *  Add a closed rectangle contour to the path
611      *
612      *  @param left     The left side of a rectangle to add as a closed contour
613      *                  to the path
614      *  @param top      The top of a rectangle to add as a closed contour to the
615      *                  path
616      *  @param right    The right side of a rectangle to add as a closed contour
617      *                  to the path
618      *  @param bottom   The bottom of a rectangle to add as a closed contour to
619      *                  the path
620      *  @param dir  The direction to wind the rectangle's contour. Cannot be
621      *              kUnknown_Direction.
622      */
623     void addRect(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom,
624                  Direction dir = kCW_Direction);
625 
626     /**
627      *  Add a closed oval contour to the path
628      *
629      *  @param oval The bounding oval to add as a closed contour to the path
630      *  @param dir  The direction to wind the oval's contour. Cannot be
631      *              kUnknown_Direction.
632      */
633     void addOval(const SkRect& oval, Direction dir = kCW_Direction);
634 
635     /**
636      *  Add a closed circle contour to the path
637      *
638      *  @param x        The x-coordinate of the center of a circle to add as a
639      *                  closed contour to the path
640      *  @param y        The y-coordinate of the center of a circle to add as a
641      *                  closed contour to the path
642      *  @param radius   The radius of a circle to add as a closed contour to the
643      *                  path
644      *  @param dir  The direction to wind the circle's contour. Cannot be
645      *              kUnknown_Direction.
646      */
647     void addCircle(SkScalar x, SkScalar y, SkScalar radius,
648                    Direction dir = kCW_Direction);
649 
650     /** Add the specified arc to the path as a new contour.
651 
652         @param oval The bounds of oval used to define the size of the arc
653         @param startAngle Starting angle (in degrees) where the arc begins
654         @param sweepAngle Sweep angle (in degrees) measured clockwise
655     */
656     void addArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle);
657 
658     /**
659      *  Add a closed round-rectangle contour to the path
660      *  @param rect The bounds of a round-rectangle to add as a closed contour
661      *  @param rx   The x-radius of the rounded corners on the round-rectangle
662      *  @param ry   The y-radius of the rounded corners on the round-rectangle
663      *  @param dir  The direction to wind the rectangle's contour. Cannot be
664      *              kUnknown_Direction.
665      */
666     void addRoundRect(const SkRect& rect, SkScalar rx, SkScalar ry,
667                       Direction dir = kCW_Direction);
668 
669     /**
670      *  Add a closed round-rectangle contour to the path. Each corner receives
671      *  two radius values [X, Y]. The corners are ordered top-left, top-right,
672      *  bottom-right, bottom-left.
673      *  @param rect The bounds of a round-rectangle to add as a closed contour
674      *  @param radii Array of 8 scalars, 4 [X,Y] pairs for each corner
675      *  @param dir  The direction to wind the rectangle's contour. Cannot be
676      *              kUnknown_Direction.
677      * Note: The radii here now go through the same constraint handling as the
678      *       SkRRect radii (i.e., either radii at a corner being 0 implies a
679      *       sqaure corner and oversized radii are proportionally scaled down).
680      */
681     void addRoundRect(const SkRect& rect, const SkScalar radii[],
682                       Direction dir = kCW_Direction);
683 
684     /**
685      *  Add an SkRRect contour to the path
686      *  @param rrect The rounded rect to add as a closed contour
687      *  @param dir   The winding direction for the new contour. Cannot be
688      *               kUnknown_Direction.
689      */
690     void addRRect(const SkRRect& rrect, Direction dir = kCW_Direction);
691 
692     /**
693      *  Add a new contour made of just lines. This is just a fast version of
694      *  the following:
695      *      this->moveTo(pts[0]);
696      *      for (int i = 1; i < count; ++i) {
697      *          this->lineTo(pts[i]);
698      *      }
699      *      if (close) {
700      *          this->close();
701      *      }
702      */
703     void addPoly(const SkPoint pts[], int count, bool close);
704 
705     enum AddPathMode {
706         /** Source path contours are added as new contours.
707         */
708         kAppend_AddPathMode,
709         /** Path is added by extending the last contour of the destination path
710             with the first contour of the source path. If the last contour of
711             the destination path is closed, then it will not be extended.
712             Instead, the start of source path will be extended by a straight
713             line to the end point of the destination path.
714         */
715         kExtend_AddPathMode
716     };
717 
718     /** Add a copy of src to the path, offset by (dx,dy)
719         @param src  The path to add as a new contour
720         @param dx   The amount to translate the path in X as it is added
721         @param dx   The amount to translate the path in Y as it is added
722     */
723     void addPath(const SkPath& src, SkScalar dx, SkScalar dy,
724                  AddPathMode mode = kAppend_AddPathMode);
725 
726     /** Add a copy of src to the path
727     */
728     void addPath(const SkPath& src, AddPathMode mode = kAppend_AddPathMode) {
729         SkMatrix m;
730         m.reset();
731         this->addPath(src, m, mode);
732     }
733 
734     /** Add a copy of src to the path, transformed by matrix
735         @param src  The path to add as a new contour
736         @param matrix  Transform applied to src
737         @param mode  Determines how path is added
738     */
739     void addPath(const SkPath& src, const SkMatrix& matrix, AddPathMode mode = kAppend_AddPathMode);
740 
741     /**
742      *  Same as addPath(), but reverses the src input
743      */
744     void reverseAddPath(const SkPath& src);
745 
746     /** Offset the path by (dx,dy), returning true on success
747 
748         @param dx   The amount in the X direction to offset the entire path
749         @param dy   The amount in the Y direction to offset the entire path
750         @param dst  The translated path is written here
751     */
752     void offset(SkScalar dx, SkScalar dy, SkPath* dst) const;
753 
754     /** Offset the path by (dx,dy), returning true on success
755 
756         @param dx   The amount in the X direction to offset the entire path
757         @param dy   The amount in the Y direction to offset the entire path
758     */
offset(SkScalar dx,SkScalar dy)759     void offset(SkScalar dx, SkScalar dy) {
760         this->offset(dx, dy, this);
761     }
762 
763     /** Transform the points in this path by matrix, and write the answer into
764         dst.
765 
766         @param matrix   The matrix to apply to the path
767         @param dst      The transformed path is written here
768     */
769     void transform(const SkMatrix& matrix, SkPath* dst) const;
770 
771     /** Transform the points in this path by matrix
772 
773         @param matrix The matrix to apply to the path
774     */
transform(const SkMatrix & matrix)775     void transform(const SkMatrix& matrix) {
776         this->transform(matrix, this);
777     }
778 
779     /** Return the last point on the path. If no points have been added, (0,0)
780         is returned. If there are no points, this returns false, otherwise it
781         returns true.
782 
783         @param lastPt   The last point on the path is returned here
784     */
785     bool getLastPt(SkPoint* lastPt) const;
786 
787     /** Set the last point on the path. If no points have been added,
788         moveTo(x,y) is automatically called.
789 
790         @param x    The new x-coordinate for the last point
791         @param y    The new y-coordinate for the last point
792     */
793     void setLastPt(SkScalar x, SkScalar y);
794 
795     /** Set the last point on the path. If no points have been added, moveTo(p)
796         is automatically called.
797 
798         @param p    The new location for the last point
799     */
setLastPt(const SkPoint & p)800     void setLastPt(const SkPoint& p) {
801         this->setLastPt(p.fX, p.fY);
802     }
803 
804     enum SegmentMask {
805         kLine_SegmentMask   = 1 << 0,
806         kQuad_SegmentMask   = 1 << 1,
807         kConic_SegmentMask  = 1 << 2,
808         kCubic_SegmentMask  = 1 << 3,
809     };
810 
811     /**
812      *  Returns a mask, where each bit corresponding to a SegmentMask is
813      *  set if the path contains 1 or more segments of that type.
814      *  Returns 0 for an empty path (no segments).
815      */
getSegmentMasks()816     uint32_t getSegmentMasks() const { return fPathRef->getSegmentMasks(); }
817 
818     enum Verb {
819         kMove_Verb,     //!< iter.next returns 1 point
820         kLine_Verb,     //!< iter.next returns 2 points
821         kQuad_Verb,     //!< iter.next returns 3 points
822         kConic_Verb,    //!< iter.next returns 3 points + iter.conicWeight()
823         kCubic_Verb,    //!< iter.next returns 4 points
824         kClose_Verb,    //!< iter.next returns 1 point (contour's moveTo pt)
825         kDone_Verb,     //!< iter.next returns 0 points
826     };
827 
828     /** Iterate through all of the segments (lines, quadratics, cubics) of
829         each contours in a path.
830 
831         The iterator cleans up the segments along the way, removing degenerate
832         segments and adding close verbs where necessary. When the forceClose
833         argument is provided, each contour (as defined by a new starting
834         move command) will be completed with a close verb regardless of the
835         contour's contents.
836     */
837     class SK_API Iter {
838     public:
839         Iter();
840         Iter(const SkPath&, bool forceClose);
841 
842         void setPath(const SkPath&, bool forceClose);
843 
844         /** Return the next verb in this iteration of the path. When all
845             segments have been visited, return kDone_Verb.
846 
847             @param  pts The points representing the current verb and/or segment
848             @param doConsumeDegerates If true, first scan for segments that are
849                    deemed degenerate (too short) and skip those.
850             @return The verb for the current segment
851         */
852         Verb next(SkPoint pts[4], bool doConsumeDegerates = true) {
853             if (doConsumeDegerates) {
854                 this->consumeDegenerateSegments();
855             }
856             return this->doNext(pts);
857         }
858 
859         /**
860          *  Return the weight for the current conic. Only valid if the current
861          *  segment return by next() was a conic.
862          */
conicWeight()863         SkScalar conicWeight() const { return *fConicWeights; }
864 
865         /** If next() returns kLine_Verb, then this query returns true if the
866             line was the result of a close() command (i.e. the end point is the
867             initial moveto for this contour). If next() returned a different
868             verb, this returns an undefined value.
869 
870             @return If the last call to next() returned kLine_Verb, return true
871                     if it was the result of an explicit close command.
872         */
isCloseLine()873         bool isCloseLine() const { return SkToBool(fCloseLine); }
874 
875         /** Returns true if the current contour is closed (has a kClose_Verb)
876             @return true if the current contour is closed (has a kClose_Verb)
877         */
878         bool isClosedContour() const;
879 
880     private:
881         const SkPoint*  fPts;
882         const uint8_t*  fVerbs;
883         const uint8_t*  fVerbStop;
884         const SkScalar* fConicWeights;
885         SkPoint         fMoveTo;
886         SkPoint         fLastPt;
887         SkBool8         fForceClose;
888         SkBool8         fNeedClose;
889         SkBool8         fCloseLine;
890         SkBool8         fSegmentState;
891 
892         inline const SkPoint& cons_moveTo();
893         Verb autoClose(SkPoint pts[2]);
894         void consumeDegenerateSegments();
895         Verb doNext(SkPoint pts[4]);
896     };
897 
898     /** Iterate through the verbs in the path, providing the associated points.
899     */
900     class SK_API RawIter {
901     public:
902         RawIter();
903         RawIter(const SkPath&);
904 
905         void setPath(const SkPath&);
906 
907         /** Return the next verb in this iteration of the path. When all
908             segments have been visited, return kDone_Verb.
909 
910             @param  pts The points representing the current verb and/or segment
911                         This must not be NULL.
912             @return The verb for the current segment
913         */
914         Verb next(SkPoint pts[4]);
915 
conicWeight()916         SkScalar conicWeight() const { return *fConicWeights; }
917 
918     private:
919         const SkPoint*  fPts;
920         const uint8_t*  fVerbs;
921         const uint8_t*  fVerbStop;
922         const SkScalar* fConicWeights;
923         SkPoint         fMoveTo;
924         SkPoint         fLastPt;
925     };
926 
927     /**
928      *  Returns true if the point { x, y } is contained by the path, taking into
929      *  account the FillType.
930      */
931     bool contains(SkScalar x, SkScalar y) const;
932 
933     void dump(bool forceClose, const char title[] = NULL) const;
934     void dump() const;
935 
936     /**
937      *  Write the path to the buffer, and return the number of bytes written.
938      *  If buffer is NULL, it still returns the number of bytes.
939      */
940     size_t writeToMemory(void* buffer) const;
941     /**
942      * Initializes the path from the buffer
943      *
944      * @param buffer Memory to read from
945      * @param length Amount of memory available in the buffer
946      * @return number of bytes read (must be a multiple of 4) or
947      *         0 if there was not enough memory available
948      */
949     size_t readFromMemory(const void* buffer, size_t length);
950 
951     /** Returns a non-zero, globally unique value corresponding to the set of verbs
952         and points in the path (but not the fill type [except on Android skbug.com/1762]).
953         Each time the path is modified, a different generation ID will be returned.
954     */
955     uint32_t getGenerationID() const;
956 
957 #ifdef SK_BUILD_FOR_ANDROID
958     static const int kPathRefGenIDBitCnt = 30; // leave room for the fill type (skbug.com/1762)
959     const SkPath* getSourcePath() const;
960     void setSourcePath(const SkPath* path);
961 #else
962     static const int kPathRefGenIDBitCnt = 32;
963 #endif
964 
965     SkDEBUGCODE(void validate() const;)
966 
967 private:
968     enum SerializationOffsets {
969         // 1 free bit at 29
970         kUnused1_SerializationShift = 28,    // 1 free bit
971         kDirection_SerializationShift = 26, // requires 2 bits
972         kUnused2_SerializationShift = 25,    // 1 free bit
973         // 1 free bit at 24
974         kConvexity_SerializationShift = 16, // requires 8 bits
975         kFillType_SerializationShift = 8,   // requires 8 bits
976         // 8 free bits at 0
977     };
978 
979     SkAutoTUnref<SkPathRef> fPathRef;
980 
981     int                 fLastMoveToIndex;
982     uint8_t             fFillType;
983     mutable uint8_t     fConvexity;
984     mutable uint8_t     fDirection;
985 #ifdef SK_BUILD_FOR_ANDROID
986     const SkPath*       fSourcePath;
987 #endif
988 
989     /** Resets all fields other than fPathRef to their initial 'empty' values.
990      *  Assumes the caller has already emptied fPathRef.
991      *  On Android increments fGenerationID without reseting it.
992      */
993     void resetFields();
994 
995     /** Sets all fields other than fPathRef to the values in 'that'.
996      *  Assumes the caller has already set fPathRef.
997      *  Doesn't change fGenerationID or fSourcePath on Android.
998      */
999     void copyFields(const SkPath& that);
1000 
1001     friend class Iter;
1002 
1003     friend class SkPathStroker;
1004 
1005     /*  Append, in reverse order, the first contour of path, ignoring path's
1006         last point. If no moveTo() call has been made for this contour, the
1007         first point is automatically set to (0,0).
1008     */
1009     void reversePathTo(const SkPath&);
1010 
1011     // called before we add points for lineTo, quadTo, cubicTo, checking to see
1012     // if we need to inject a leading moveTo first
1013     //
1014     //  SkPath path; path.lineTo(...);   <--- need a leading moveTo(0, 0)
1015     // SkPath path; ... path.close(); path.lineTo(...) <-- need a moveTo(previous moveTo)
1016     //
1017     inline void injectMoveToIfNeeded();
1018 
1019     inline bool hasOnlyMoveTos() const;
1020 
1021     Convexity internalGetConvexity() const;
1022 
1023     bool isRectContour(bool allowPartial, int* currVerb, const SkPoint** pts,
1024                        bool* isClosed, Direction* direction) const;
1025 
1026     /** Returns if the path can return a bound at no cost (true) or will have to
1027         perform some computation (false).
1028      */
hasComputedBounds()1029     bool hasComputedBounds() const {
1030         SkDEBUGCODE(this->validate();)
1031         return fPathRef->hasComputedBounds();
1032     }
1033 
1034 
1035     // 'rect' needs to be sorted
setBounds(const SkRect & rect)1036     void setBounds(const SkRect& rect) {
1037         SkPathRef::Editor ed(&fPathRef);
1038 
1039         ed.setBounds(rect);
1040     }
1041 
1042     friend class SkAutoPathBoundsUpdate;
1043     friend class SkAutoDisableOvalCheck;
1044     friend class SkAutoDisableDirectionCheck;
1045     friend class SkBench_AddPathTest; // perf test reversePathTo
1046     friend class PathTest_Private; // unit test reversePathTo
1047 };
1048 
1049 #endif
1050