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

branch
TOR_BUG_3246
changeset 7
129ffea94266
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-1:000000000000 0:b55e1d595a7b
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 SkPathMeasure_DEFINED
9 #define SkPathMeasure_DEFINED
10
11 #include "SkPath.h"
12 #include "SkTDArray.h"
13
14 class SK_API SkPathMeasure : SkNoncopyable {
15 public:
16 SkPathMeasure();
17 /** Initialize the pathmeasure with the specified path. The path must remain valid
18 for the lifetime of the measure object, or until setPath() is called with
19 a different path (or null), since the measure object keeps a pointer to the
20 path object (does not copy its data).
21 */
22 SkPathMeasure(const SkPath& path, bool forceClosed);
23 ~SkPathMeasure();
24
25 /** Reset the pathmeasure with the specified path. The path must remain valid
26 for the lifetime of the measure object, or until setPath() is called with
27 a different path (or null), since the measure object keeps a pointer to the
28 path object (does not copy its data).
29 */
30 void setPath(const SkPath*, bool forceClosed);
31
32 /** Return the total length of the current contour, or 0 if no path
33 is associated (e.g. resetPath(null))
34 */
35 SkScalar getLength();
36
37 /** Pins distance to 0 <= distance <= getLength(), and then computes
38 the corresponding position and tangent.
39 Returns false if there is no path, or a zero-length path was specified, in which case
40 position and tangent are unchanged.
41 */
42 bool SK_WARN_UNUSED_RESULT getPosTan(SkScalar distance, SkPoint* position,
43 SkVector* tangent);
44
45 enum MatrixFlags {
46 kGetPosition_MatrixFlag = 0x01,
47 kGetTangent_MatrixFlag = 0x02,
48 kGetPosAndTan_MatrixFlag = kGetPosition_MatrixFlag | kGetTangent_MatrixFlag
49 };
50
51 /** Pins distance to 0 <= distance <= getLength(), and then computes
52 the corresponding matrix (by calling getPosTan).
53 Returns false if there is no path, or a zero-length path was specified, in which case
54 matrix is unchanged.
55 */
56 bool SK_WARN_UNUSED_RESULT getMatrix(SkScalar distance, SkMatrix* matrix,
57 MatrixFlags flags = kGetPosAndTan_MatrixFlag);
58
59 /** Given a start and stop distance, return in dst the intervening segment(s).
60 If the segment is zero-length, return false, else return true.
61 startD and stopD are pinned to legal values (0..getLength()). If startD <= stopD
62 then return false (and leave dst untouched).
63 Begin the segment with a moveTo if startWithMoveTo is true
64 */
65 bool getSegment(SkScalar startD, SkScalar stopD, SkPath* dst, bool startWithMoveTo);
66
67 /** Return true if the current contour is closed()
68 */
69 bool isClosed();
70
71 /** Move to the next contour in the path. Return true if one exists, or false if
72 we're done with the path.
73 */
74 bool nextContour();
75
76 #ifdef SK_DEBUG
77 void dump();
78 #endif
79
80 private:
81 SkPath::Iter fIter;
82 const SkPath* fPath;
83 SkScalar fLength; // relative to the current contour
84 int fFirstPtIndex; // relative to the current contour
85 bool fIsClosed; // relative to the current contour
86 bool fForceClosed;
87
88 struct Segment {
89 SkScalar fDistance; // total distance up to this point
90 unsigned fPtIndex : 15; // index into the fPts array
91 unsigned fTValue : 15;
92 unsigned fType : 2;
93
94 SkScalar getScalarT() const;
95 };
96 SkTDArray<Segment> fSegments;
97 SkTDArray<SkPoint> fPts; // Points used to define the segments
98
99 static const Segment* NextSegment(const Segment*);
100
101 void buildSegments();
102 SkScalar compute_quad_segs(const SkPoint pts[3], SkScalar distance,
103 int mint, int maxt, int ptIndex);
104 SkScalar compute_cubic_segs(const SkPoint pts[3], SkScalar distance,
105 int mint, int maxt, int ptIndex);
106 const Segment* distanceToSegment(SkScalar distance, SkScalar* t);
107 };
108
109 #endif

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