|
1 /* |
|
2 * Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies). |
|
3 * All rights reserved. |
|
4 * This component and the accompanying materials are made available |
|
5 * under the terms of "Eclipse Public License v1.0" |
|
6 * which accompanies this distribution, and is available |
|
7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
|
8 * |
|
9 * Initial Contributors: |
|
10 * Nokia Corporation - initial contribution. |
|
11 * |
|
12 * Contributors: |
|
13 * |
|
14 * Description: Gesture helper implementation |
|
15 * |
|
16 */ |
|
17 |
|
18 #include <e32math.h> |
|
19 |
|
20 #include "xngesturerecogniser.h" |
|
21 #include "xngesturedefs.h" |
|
22 #include "xnpointarray.h" |
|
23 |
|
24 using namespace XnGestureHelper; |
|
25 |
|
26 /** |
|
27 * Vector class (math) |
|
28 */ |
|
29 NONSHARABLE_CLASS( TVector ) |
|
30 { |
|
31 public: |
|
32 /** |
|
33 * Constructor |
|
34 * @param aFrom starting point of the vector |
|
35 * @param aTo ending point of the vector |
|
36 */ |
|
37 TVector( const TPoint& aFrom, const TPoint& aTo ) |
|
38 : iX( aTo.iX - aFrom.iX ), |
|
39 iY( aTo.iY - aFrom.iY ) |
|
40 { |
|
41 } |
|
42 |
|
43 /** @return angle of the vector */ |
|
44 TReal Angle() const |
|
45 { |
|
46 TReal angle = 0; |
|
47 TReal length = Length(); |
|
48 if ( length != 0 ) |
|
49 { |
|
50 Math::ACos( angle, iX / Length() ); |
|
51 if ( iY < 0 ) |
|
52 { |
|
53 angle = 2 * KPi - angle; |
|
54 } |
|
55 } |
|
56 return Degrees( angle ); |
|
57 } |
|
58 |
|
59 /** @return length of the vector */ |
|
60 TReal Length() const |
|
61 { |
|
62 TReal length = 0; |
|
63 Math::Sqrt( length, iX * iX + iY * iY ); |
|
64 return length; |
|
65 } |
|
66 |
|
67 private: |
|
68 /** @return radians in degrees */ |
|
69 inline TReal Degrees( TReal aRadians ) const |
|
70 { |
|
71 return aRadians * 180 / KPi; |
|
72 } |
|
73 |
|
74 public: |
|
75 /// x coordinate that represent the vector |
|
76 TReal iX; |
|
77 /// y coordinate that represent the vector |
|
78 TReal iY; |
|
79 }; |
|
80 |
|
81 /** |
|
82 * @return ETrue if points for a tap event |
|
83 */ |
|
84 inline TBool IsTap( const TXnPointArray& aPoints ) |
|
85 { |
|
86 // with tap, the pointer is not allowed to leave the tap area and come back |
|
87 // therefore, gesture length is not an acceptable test for tap, as it tests |
|
88 // only the last point. therefore, check if *any* point is outside tap area. |
|
89 TInt i = aPoints.Count(); // latest point if most likely to be outside tap area |
|
90 while ( --i >= 0 ) |
|
91 { |
|
92 // use the raw point (from which no axis has been filtered out) |
|
93 // because tap should consider both axes even when Code() ignores one axis |
|
94 if ( KSamePointTolerance < Abs( aPoints.Raw( i ).iX - aPoints.Raw( 0 ).iX ) || |
|
95 KSamePointTolerance < Abs( aPoints.Raw( i ).iY - aPoints.Raw( 0 ).iY ) ) |
|
96 { |
|
97 return EFalse; |
|
98 } |
|
99 } |
|
100 return ETrue; |
|
101 } |
|
102 |
|
103 /** |
|
104 * @return Length of the gesture in points |
|
105 */ |
|
106 inline TReal GestureLength( const TXnPointArray& aPoints ) |
|
107 { |
|
108 return TVector( aPoints[0], aPoints[aPoints.Count() - 1] ).Length(); |
|
109 } |
|
110 |
|
111 /** |
|
112 * @return ETrue if aAngleUnderTest is almost aAngle |
|
113 * Closeness of the angles is controlled by KAngleTolerance |
|
114 */ |
|
115 static TBool IsNear( TReal aAngleUnderTest, TReal aAngle ) |
|
116 { |
|
117 return aAngle - KAngleTolerance <= aAngleUnderTest && |
|
118 aAngleUnderTest <= aAngle + KAngleTolerance; |
|
119 } |
|
120 |
|
121 /** |
|
122 * @return the angle as a direction flags of TGesture |
|
123 */ |
|
124 inline TXnGestureCode Direction( TReal aAngle ) |
|
125 { |
|
126 TXnGestureCode direction = EGestureUnknown; |
|
127 |
|
128 if ( IsNear( aAngle, 90.0 ) ) |
|
129 { |
|
130 direction = EGestureSwipeDown; |
|
131 } |
|
132 else if ( IsNear( aAngle, 180.0 ) ) |
|
133 { |
|
134 direction = EGestureSwipeLeft; |
|
135 } |
|
136 else if ( IsNear( aAngle, 270.0 ) ) |
|
137 { |
|
138 direction = EGestureSwipeUp; |
|
139 } |
|
140 else if ( 360.0 - KAngleTolerance <= aAngle || aAngle <= KAngleTolerance ) |
|
141 { |
|
142 direction = EGestureSwipeRight; |
|
143 } |
|
144 else // for lint warning |
|
145 { |
|
146 // unknown angle |
|
147 } |
|
148 |
|
149 return direction; |
|
150 } |
|
151 |
|
152 /** @return direction between points */ |
|
153 inline TXnGestureCode Direction( const TPoint& aFromPoint, const TPoint& aToPoint ) |
|
154 { |
|
155 return Direction( TVector( aFromPoint, aToPoint ).Angle() ); |
|
156 } |
|
157 |
|
158 /** @return overall direction between points */ |
|
159 static TXnGestureCode GeneralDirection( const TXnPointArray& aPoints ) |
|
160 { |
|
161 return Direction( aPoints[0], aPoints[aPoints.Count() - 1]); |
|
162 } |
|
163 |
|
164 /** |
|
165 * @return the last received point that is different that the latest point, |
|
166 * or first point if no point is different than latest |
|
167 */ |
|
168 inline TPoint PreviousPoint( const TXnPointArray& aPoints ) |
|
169 { |
|
170 TPoint latestPoint = aPoints[aPoints.Count() - 1]; |
|
171 TInt i = aPoints.Count() - 1; |
|
172 while ( --i >= 0 ) |
|
173 { |
|
174 if ( latestPoint != aPoints[i] ) |
|
175 { |
|
176 return aPoints[i]; |
|
177 } |
|
178 } |
|
179 return aPoints[0]; |
|
180 } |
|
181 |
|
182 /** @return direction between last two points */ |
|
183 inline TXnGestureCode LastDirection( const TXnPointArray& aPoints ) |
|
184 { |
|
185 if ( aPoints.Count() > 1 ) |
|
186 { |
|
187 // return direction between latest and previous points. |
|
188 // pick the previous point that is different than the last point |
|
189 // because while using an x or y filter array, more than one |
|
190 // sequential points may look like the same point because |
|
191 // the differing coordinate coordinate is filtered out. For example, |
|
192 // if dragging left and slightly up, many y coordinates will have the |
|
193 // same value, while only x differs. |
|
194 return Direction( PreviousPoint( aPoints ), aPoints[aPoints.Count() - 1] ); |
|
195 } |
|
196 return EGestureUnknown; |
|
197 } |
|
198 |
|
199 // ---------------------------------------------------------------------------- |
|
200 // Return gesture code of a gesture formed by a sequence of points |
|
201 // ---------------------------------------------------------------------------- |
|
202 // |
|
203 TXnGestureCode TXnGestureRecogniser::GestureCode( const TXnPointArray& aPoints ) const |
|
204 { |
|
205 __ASSERT_DEBUG( aPoints.Count() > 0, Panic( EGesturePanicIllegalLogic ) ); |
|
206 |
|
207 if (aPoints.Count() <= 0) |
|
208 return EGestureUnknown; |
|
209 |
|
210 if ( IsTap( aPoints ) ) |
|
211 { |
|
212 return EGestureTap; |
|
213 } |
|
214 |
|
215 if ( GestureLength( aPoints ) >= KMinSwipeLength ) |
|
216 { |
|
217 TXnGestureCode direction = GeneralDirection( aPoints ); |
|
218 if ( direction != LastDirection( aPoints ) ) |
|
219 { |
|
220 direction = EGestureUnknown; |
|
221 } |
|
222 return direction; |
|
223 } |
|
224 |
|
225 // the pointer was moved but was either not moved far enough, or was |
|
226 // brought back to close to the starting point |
|
227 return EGestureUnknown; |
|
228 } |