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      1 /*
      2  * Copyright 2006 The Android Open Source Project
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 #ifndef SkDiscretePathEffect_DEFINED
      9 #define SkDiscretePathEffect_DEFINED
     10 
     11 #include "SkPathEffect.h"
     12 
     13 /** \class SkDiscretePathEffect
     14 
     15     This path effect chops a path into discrete segments, and randomly displaces them.
     16 */
     17 class SK_API SkDiscretePathEffect : public SkPathEffect {
     18 public:
     19     /** Break the path into segments of segLength length, and randomly move the endpoints
     20         away from the original path by a maximum of deviation.
     21         Note: works on filled or framed paths
     22 
     23         @param seedAssist This is a caller-supplied seedAssist that modifies
     24                           the seed value that is used to randomize the path
     25                           segments' endpoints. If not supplied it defaults to 0,
     26                           in which case filtering a path multiple times will
     27                           result in the same set of segments (this is useful for
     28                           testing). If a caller does not want this behaviour
     29                           they can pass in a different seedAssist to get a
     30                           different set of path segments.
     31     */
     32     static SkDiscretePathEffect* Create(SkScalar segLength,
     33                                         SkScalar deviation,
     34                                         uint32_t seedAssist=0) {
     35         return SkNEW_ARGS(SkDiscretePathEffect,
     36                           (segLength, deviation, seedAssist));
     37     }
     38 
     39     virtual bool filterPath(SkPath* dst, const SkPath& src,
     40                             SkStrokeRec*, const SkRect*) const SK_OVERRIDE;
     41 
     42     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDiscretePathEffect)
     43 
     44 protected:
     45     SkDiscretePathEffect(SkScalar segLength,
     46                          SkScalar deviation,
     47                          uint32_t seedAssist);
     48 #ifdef SK_SUPPORT_LEGACY_DEEPFLATTENING
     49     explicit SkDiscretePathEffect(SkReadBuffer&);
     50 #endif
     51     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
     52 
     53 private:
     54     SkScalar fSegLength, fPerterb;
     55 
     56     /* Caller-supplied 32 bit seed assist */
     57     uint32_t fSeedAssist;
     58 
     59     typedef SkPathEffect INHERITED;
     60 };
     61 
     62 #endif
     63