reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2006 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef SkPathMeasure_DEFINED |
| 18 | #define SkPathMeasure_DEFINED |
| 19 | |
| 20 | #include "SkPath.h" |
| 21 | #include "SkTDArray.h" |
| 22 | |
| 23 | class SkPathMeasure : SkNoncopyable { |
| 24 | public: |
| 25 | SkPathMeasure(); |
| 26 | /** Initialize the pathmeasure with the specified path. The path must remain valid |
| 27 | for the lifetime of the measure object, or until setPath() is called with |
| 28 | a different path (or null), since the measure object keeps a pointer to the |
| 29 | path object (does not copy its data). |
| 30 | */ |
| 31 | SkPathMeasure(const SkPath& path, bool forceClosed); |
| 32 | ~SkPathMeasure(); |
| 33 | |
| 34 | /** Reset the pathmeasure with the specified path. The path must remain valid |
| 35 | for the lifetime of the measure object, or until setPath() is called with |
| 36 | a different path (or null), since the measure object keeps a pointer to the |
| 37 | path object (does not copy its data). |
| 38 | */ |
| 39 | void setPath(const SkPath*, bool forceClosed); |
| 40 | |
| 41 | /** Return the total length of the current contour, or 0 if no path |
| 42 | is associated (e.g. resetPath(null)) |
| 43 | */ |
| 44 | SkScalar getLength(); |
| 45 | |
| 46 | /** Pins distance to 0 <= distance <= getLength(), and then computes |
| 47 | the corresponding position and tangent. |
| 48 | Returns false if there is no path, or a zero-length path was specified, in which case |
| 49 | position and tangent are unchanged. |
| 50 | */ |
| 51 | bool getPosTan(SkScalar distance, SkPoint* position, SkVector* tangent); |
| 52 | |
| 53 | enum MatrixFlags { |
| 54 | kGetPosition_MatrixFlag = 0x01, |
| 55 | kGetTangent_MatrixFlag = 0x02, |
| 56 | kGetPosAndTan_MatrixFlag = kGetPosition_MatrixFlag | kGetTangent_MatrixFlag |
| 57 | }; |
| 58 | /** Pins distance to 0 <= distance <= getLength(), and then computes |
| 59 | the corresponding matrix (by calling getPosTan). |
| 60 | Returns false if there is no path, or a zero-length path was specified, in which case |
| 61 | matrix is unchanged. |
| 62 | */ |
| 63 | bool getMatrix(SkScalar distance, SkMatrix* matrix, MatrixFlags flags = kGetPosAndTan_MatrixFlag); |
| 64 | /** Given a start and stop distance, return in dst the intervening segment(s). |
| 65 | If the segment is zero-length, return false, else return true. |
| 66 | startD and stopD are pinned to legal values (0..getLength()). If startD <= stopD |
| 67 | then return false (and leave dst untouched). |
| 68 | Begin the segment with a moveTo if startWithMoveTo is true |
| 69 | */ |
| 70 | bool getSegment(SkScalar startD, SkScalar stopD, SkPath* dst, bool startWithMoveTo); |
| 71 | |
| 72 | /** Return true if the current contour is closed() |
| 73 | */ |
| 74 | bool isClosed(); |
| 75 | |
| 76 | /** Move to the next contour in the path. Return true if one exists, or false if |
| 77 | we're done with the path. |
| 78 | */ |
| 79 | bool nextContour(); |
| 80 | |
| 81 | #ifdef SK_DEBUG |
| 82 | void dump(); |
| 83 | static void UnitTest(); |
| 84 | #endif |
| 85 | |
| 86 | private: |
| 87 | SkPath::Iter fIter; |
| 88 | const SkPath* fPath; |
| 89 | SkScalar fLength; // relative to the current contour |
| 90 | int fFirstPtIndex; // relative to the current contour |
| 91 | bool fIsClosed; // relative to the current contour |
| 92 | bool fForceClosed; |
| 93 | |
| 94 | struct Segment { |
| 95 | SkScalar fDistance; // total distance up to this point |
| 96 | unsigned fPtIndex : 15; |
| 97 | unsigned fTValue : 15; |
| 98 | unsigned fType : 2; |
| 99 | |
| 100 | SkScalar getScalarT() const; |
| 101 | }; |
| 102 | SkTDArray<Segment> fSegments; |
| 103 | |
| 104 | static const Segment* NextSegment(const Segment*); |
| 105 | |
| 106 | void buildSegments(); |
| 107 | SkScalar compute_quad_segs(const SkPoint pts[3], SkScalar distance, |
| 108 | int mint, int maxt, int ptIndex); |
| 109 | SkScalar compute_cubic_segs(const SkPoint pts[3], SkScalar distance, |
| 110 | int mint, int maxt, int ptIndex); |
| 111 | const Segment* distanceToSegment(SkScalar distance, SkScalar* t); |
| 112 | }; |
| 113 | |
| 114 | #endif |
| 115 | |