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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (developer.feedback@nokia.com) |
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6 ** |
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7 ** This file is part of the HbCore module of the UI Extensions for Mobile. |
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8 ** |
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9 ** GNU Lesser General Public License Usage |
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10 ** This file may be used under the terms of the GNU Lesser General Public |
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11 ** License version 2.1 as published by the Free Software Foundation and |
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12 ** appearing in the file LICENSE.LGPL included in the packaging of this file. |
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13 ** Please review the following information to ensure the GNU Lesser General |
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14 ** Public License version 2.1 requirements will be met: |
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15 ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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16 ** |
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17 ** In addition, as a special exception, Nokia gives you certain additional |
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18 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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19 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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20 ** |
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21 ** If you have questions regarding the use of this file, please contact |
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22 ** Nokia at developer.feedback@nokia.com. |
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23 ** |
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24 ****************************************************************************/ |
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25 |
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26 #include "hbpointrecorder_p.h" |
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27 |
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28 #include <QDebug> |
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29 //#define VELOCITY_DEBUG |
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30 #ifndef VELOCITY_DEBUG |
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31 # define DEBUG if (0) qDebug |
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32 #else |
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33 # define DEBUG qDebug |
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34 #endif |
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35 |
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36 /*! |
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37 @hbcore |
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38 \internal |
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39 \class HbPointRecorder |
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40 |
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41 \brief Class to store and hold list of points and timestamps. |
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42 |
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43 */ |
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44 |
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45 /*! |
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46 \internal |
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47 \brief Constructor for HbPointRecorder |
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48 \return |
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49 |
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50 */ |
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51 HbPointRecorder::HbPointRecorder() |
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52 { |
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53 } |
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54 |
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55 /*! |
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56 \internal |
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57 \brief Destructor for HbPointRecorder |
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58 \return |
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59 |
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60 */ |
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61 HbPointRecorder::~HbPointRecorder() |
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62 { |
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63 } |
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64 |
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65 /*! |
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66 \internal |
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67 \brief Records point to list with timestamp. |
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68 \param point Point to be recorded. |
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69 \param time Time to be recorded. |
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70 \return Nothing. |
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71 |
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72 */ |
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73 void HbPointRecorder::record(qreal point, QTime time) |
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74 { |
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75 // No point to record a point, if timestamp is less or equal with previous. |
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76 if ( !isEmpty() && lastTime().msecsTo(time) == 0 ) |
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77 { |
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78 DEBUG() << "Ignoring point, because no difference in time stamps."; |
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79 return; |
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80 } |
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81 |
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82 // In case the list contains two or more points, direction can be |
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83 // determined. Each new point added needs to be checked for direction |
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84 // change. |
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85 if ( mPoints.length() > 1 ) |
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86 { |
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87 // Clear list, on direction change. Leave the last recorded point |
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88 // to the list, as it can be considered as first point for new direction. |
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89 if ( dirChanged( point ) ) |
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90 { |
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91 qreal tempPoint = lastPoint(); |
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92 QTime tempTime = lastTime(); |
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93 |
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94 clear(); |
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95 |
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96 mPoints.append( tempPoint ); |
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97 mTimes.append( tempTime ); |
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98 } |
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99 } |
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100 |
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101 // Finally check, if the position has changed. Don't record point, when no position |
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102 // change. |
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103 if ( isEmpty() || point != lastPoint() ) |
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104 { |
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105 // Add point and time to list. |
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106 mPoints.append( point ); |
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107 mTimes.append( time ); |
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108 } |
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109 else |
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110 { |
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111 DEBUG() << "Ignoring point, because it equals previous."; |
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112 } |
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113 } |
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114 |
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115 /*! |
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116 \internal |
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117 \brief |
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118 \return True, when no recorded items. |
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119 |
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120 */ |
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121 bool HbPointRecorder::isEmpty() const |
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122 { |
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123 // This situation should be impossible to even happen, but in case |
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124 // the lists are out of sync. The result of empty list dictates the |
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125 // result of this test. |
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126 return !mTimes.length() && !mPoints.length(); |
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127 } |
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128 |
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129 /*! |
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130 \internal |
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131 \brief |
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132 \return Last recorded point. |
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133 |
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134 */ |
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135 qreal HbPointRecorder::lastPoint() const |
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136 { |
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137 Q_ASSERT(!isEmpty()); |
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138 return mPoints.last(); |
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139 } |
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140 |
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141 /*! |
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142 \internal |
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143 \brief |
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144 \return Last recorded timestamp. |
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145 |
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146 */ |
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147 const QTime& HbPointRecorder::lastTime() const |
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148 { |
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149 Q_ASSERT(!isEmpty()); |
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150 return mTimes.last(); |
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151 } |
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152 |
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153 /*! |
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154 \internal |
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155 \brief Checks if new point causes direction change. |
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156 \param point The point suspected cause direction change. |
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157 \return True, when direction changes. |
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158 */ |
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159 bool HbPointRecorder::dirChanged( qreal point ) const |
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160 { |
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161 qreal x0 = mPoints.at(mPoints.length()-2); |
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162 qreal x1 = mPoints.at(mPoints.length()-1); |
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163 qreal dir0 = x1 - x0; |
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164 qreal dir1 = point - x1; |
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165 |
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166 // Check for '+' and '-' -signs in directions. Opposite signs means |
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167 // direction change. |
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168 return ( dir0 < 0 && dir1 >= 0 ) || ( dir0 > 0 && dir1 <= 0 ); |
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169 } |
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170 |
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171 /*! |
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172 \internal |
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173 \param T type of items in the list. |
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174 \brief Returns given number of items from the end. |
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175 \return List of items. |
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176 |
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177 This function gets items from the given list from the end by the |
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178 amount of items specified by 'number' parameter. In case, when the |
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179 length of the list is less than required number of items, complete |
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180 list is provided instead. |
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181 */ |
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182 template <class T> |
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183 QList<T> HbPointRecorder::getLastItems( QList<T> list, int number ) const |
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184 { |
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185 if ( list.length() <= number ) |
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186 { |
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187 return list; |
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188 } |
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189 else |
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190 { |
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191 QList<T> tempList; |
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192 for ( int i = list.length(); --i >= list.length()-number; ) |
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193 { |
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194 tempList.insert(0, list.at(i)); |
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195 } |
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196 return tempList; |
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197 } |
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198 } |
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199 |
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200 /*! |
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201 \internal |
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202 \copydoc HbPointRecorder::getLastItems |
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203 */ |
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204 QList<qreal> HbPointRecorder::getLastPoints( int number ) const |
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205 { |
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206 return getLastItems(mPoints, number); |
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207 } |
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208 |
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209 /*! |
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210 \internal |
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211 \copydoc HbPointRecorder::getLastItems |
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212 */ |
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213 QList<QTime> HbPointRecorder::getLastTimes( int number ) const |
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214 { |
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215 return getLastItems(mTimes, number); |
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216 } |
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217 |
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218 /*! |
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219 \internal |
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220 \brief |
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221 \return Last recorded timestamp. |
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222 |
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223 */ |
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224 void HbPointRecorder::clear() |
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225 { |
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226 mPoints.clear(); |
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227 mTimes.clear(); |
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228 } |