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1 /* |
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2 * Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: Gesture helper interface |
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15 * |
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16 */ |
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17 |
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18 #ifndef _GESTUREHELPER_H_ |
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19 #define _GESTUREHELPER_H_ |
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20 |
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21 #include <e32base.h> |
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22 #include <gestureobserver.h> |
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23 |
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24 class CAlfEnv; |
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25 class CAlfDisplay; |
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26 class TAlfEvent; |
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27 struct TPointerEvent; |
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28 |
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29 namespace GestureHelper |
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30 { |
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31 |
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32 class CGestureHelperImpl; |
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33 |
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34 /** |
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35 * Gesture helper provides functionality to convert a stream of pointer events |
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36 * into a logical gesture, and to assist clients in calculation of gesture |
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37 * speed and distance. |
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38 * |
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39 * Interfaces |
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40 * - CGestureHelper is a parser of pointer events. Recognises gestures from |
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41 * a sequence of pointer events, and converts them to gesture commands. |
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42 * For documentation of callbacks, see @ref MGestureObserver. |
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43 * - MGestureObserver allows clients to get notified of gestures |
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44 * - MGestureEvent represents the gesture (event) |
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45 */ |
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46 NONSHARABLE_CLASS( CGestureHelper ) : public CBase |
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47 { |
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48 public: |
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49 /** |
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50 * The helper is expected to be a member variable, hence NewLC is not provided |
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51 */ |
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52 IMPORT_C static CGestureHelper* NewL( MGestureObserver& aObserver ); |
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53 |
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54 /** Destructor */ |
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55 IMPORT_C ~CGestureHelper(); |
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56 |
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57 /** |
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58 * Specify whether the helper will send hold events. By default, holding is enabled. |
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59 * "Hold" means user has held stylus/finger on the same position for a longer duration. |
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60 * |
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61 * Clients that require holding to be treated with no special meaning should disable |
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62 * holding to simplify their event handling. |
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63 * For example, assume the client uses swipe left/right to control navigation, and |
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64 * holding is enabled. If user holds, the client gets hold left/right |
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65 * event, and no swipe event. If user now drags left or right while still pressing |
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66 * stylus down, the client will not get a swipe event (since it already received a hold |
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67 * event). Upon release event, the client no reliable way of knowing whether the |
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68 * user swiped left/right or cancelled the swipe. This problem is removed if the |
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69 * client simply disables holding. In the above scenario while holding disabled, |
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70 * the client would get only swipe events (and released event). |
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71 * (Swipe can be cancelled by dragging towards, but not beyond, the starting position.) |
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72 */ |
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73 IMPORT_C void SetHoldingEnabled( TBool aEnabled ); |
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74 |
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75 /** |
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76 * @return whether sending hold events is currently enabled |
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77 * ("Hold" means user has held stylus/finger on the same position for a longer duration.) |
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78 */ |
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79 IMPORT_C TBool IsHoldingEnabled() const; |
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80 |
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81 /** |
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82 * Enables/disables double tap support. Double tap is disabled by default. |
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83 * When double tap is disabled, gesture helper emits tap events immediately when |
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84 * user lifts stylus/finger. |
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85 * When double tap is enabled, tap events are emitted after the double tap timeout passes. |
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86 * The timeout is the maximum time within which the second tap will be treated |
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87 * as a double tap. That is, there is a delay (sluggishness) before client receives |
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88 * the tap event when double tap is enabled. |
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89 * tap + timeout => tap event emitted after timeout |
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90 * tap + tap before timeout => double tap event emitted immediately after the second tap |
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91 * tap + swipe => tap + swipe events |
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92 * (tap + timeout + tap + timeout => two tap events) |
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93 */ |
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94 IMPORT_C void SetDoubleTapEnabled( TBool aEnabled ); |
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95 |
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96 /** |
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97 * @return whether double tap is currently enabled. See SetDoubleTapEnabled |
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98 */ |
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99 IMPORT_C TBool IsDoubleTapEnabled() const; |
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100 |
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101 /** |
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102 * Initialise pointer capture for Alfred |
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103 * This means that helper will receive drag events and pointer events that |
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104 * go outside the original visual area |
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105 */ |
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106 IMPORT_C void InitAlfredPointerCaptureL( CAlfEnv& aEnv, CAlfDisplay& aDisplay, |
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107 TInt aFreeControlGroupId ); |
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108 |
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109 /** |
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110 * Give a pointer event to the helper, to form a part of a gesture |
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111 * For AVKON-based client, this interface is the only option. |
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112 * Alfred-based client should use OfferEventL, as it allows gesture events to |
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113 * provider the visual on which the pointer event started. |
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114 * @param aEvent pointer event |
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115 * @return whether event was consumed or not |
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116 * EFalse the event is not a pointer events and if pointer up/drag |
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117 * event received without pointer down event |
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118 * ETrue in all the other cases of pointer event |
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119 */ |
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120 IMPORT_C TBool HandlePointerEventL( const TPointerEvent& aEvent ); |
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121 |
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122 /** |
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123 * Offer an Alf event. See HandlePointerEventL. |
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124 * @return whether event was consumed or not |
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125 * EFalse the event is not a pointer events and if pointer up/drag |
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126 * event received without pointer down event |
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127 * ETrue in all the other cases of pointer event |
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128 */ |
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129 IMPORT_C TBool OfferEventL( const TAlfEvent& aEvent ); |
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130 |
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131 /** |
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132 * Cancel ongoing recognision. Purges all pointer events given earlier, and |
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133 * starts afresh. It is not necessary to call Cancel before deleting the object. |
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134 */ |
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135 IMPORT_C void Cancel(); |
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136 |
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137 /** |
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138 * Adds a new observer to gesture helper events. Replaces any earlier observer. |
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139 * This is to allow sharing of gesture helper between different controls. |
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140 * The control which is currently shown (control that is on top of the roster) |
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141 * will add as an observer and the earlier control which is now not in focus will |
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142 * automatically be removed as an observer. |
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143 * |
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144 * This API should be used only when the gesture helper is shared between more |
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145 * than one control. Gesture helper can be shared only among the controls within the same roster. |
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146 * Only required for alf based applications, not required for CCoeControl. |
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147 * |
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148 */ |
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149 IMPORT_C void AddObserver(MGestureObserver* aObserver); |
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150 |
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151 private: |
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152 /// interface implementation |
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153 CGestureHelperImpl* iImpl; |
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154 }; |
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155 |
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156 } // namespace GestureHelper |
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157 |
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158 #endif // _GESTUREHELPER_H_ |