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| 32 | <td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QRangeControl Class Reference</h1>
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| 33 |
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| 34 | <p>The QRangeControl class provides an integer value within a range.
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| 35 | <a href="#details">More...</a>
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| 36 | <p><tt>#include <<a href="qrangecontrol-h.html">qrangecontrol.h</a>></tt>
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| 37 | <p>Inherited by <a href="qdial.html">QDial</a>, <a href="qscrollbar.html">QScrollBar</a>, <a href="qslider.html">QSlider</a>, and <a href="qspinbox.html">QSpinBox</a>.
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| 38 | <p><a href="qrangecontrol-members.html">List of all member functions.</a>
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| 39 | <h2>Public Members</h2>
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| 40 | <ul>
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| 41 | <li class=fn><a href="#QRangeControl"><b>QRangeControl</b></a> ()</li>
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| 42 | <li class=fn><a href="#QRangeControl-2"><b>QRangeControl</b></a> ( int minValue, int maxValue, int lineStep, int pageStep, int value )</li>
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| 43 | <li class=fn>virtual <a href="#~QRangeControl"><b>~QRangeControl</b></a> ()</li>
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| 44 | <li class=fn>int <a href="#value"><b>value</b></a> () const</li>
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| 45 | <li class=fn>void <a href="#setValue"><b>setValue</b></a> ( int value )</li>
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| 46 | <li class=fn>void <a href="#addPage"><b>addPage</b></a> ()</li>
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| 47 | <li class=fn>void <a href="#subtractPage"><b>subtractPage</b></a> ()</li>
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| 48 | <li class=fn>void <a href="#addLine"><b>addLine</b></a> ()</li>
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| 49 | <li class=fn>void <a href="#subtractLine"><b>subtractLine</b></a> ()</li>
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| 50 | <li class=fn>int <a href="#minValue"><b>minValue</b></a> () const</li>
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| 51 | <li class=fn>int <a href="#maxValue"><b>maxValue</b></a> () const</li>
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| 52 | <li class=fn>void <a href="#setRange"><b>setRange</b></a> ( int minValue, int maxValue )</li>
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| 53 | <li class=fn>void <a href="#setMinValue"><b>setMinValue</b></a> ( int minVal )</li>
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| 54 | <li class=fn>void <a href="#setMaxValue"><b>setMaxValue</b></a> ( int maxVal )</li>
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| 55 | <li class=fn>int <a href="#lineStep"><b>lineStep</b></a> () const</li>
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| 56 | <li class=fn>int <a href="#pageStep"><b>pageStep</b></a> () const</li>
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| 57 | <li class=fn>void <a href="#setSteps"><b>setSteps</b></a> ( int lineStep, int pageStep )</li>
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| 58 | <li class=fn>int <a href="#bound"><b>bound</b></a> ( int v ) const</li>
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| 59 | </ul>
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| 60 | <h2>Protected Members</h2>
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| 61 | <ul>
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| 62 | <li class=fn>int <a href="#positionFromValue"><b>positionFromValue</b></a> ( int logical_val, int span ) const</li>
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| 63 | <li class=fn>int <a href="#valueFromPosition"><b>valueFromPosition</b></a> ( int pos, int span ) const</li>
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| 64 | <li class=fn>void <a href="#directSetValue"><b>directSetValue</b></a> ( int value )</li>
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| 65 | <li class=fn>int <a href="#prevValue"><b>prevValue</b></a> () const</li>
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| 66 | <li class=fn>virtual void <a href="#valueChange"><b>valueChange</b></a> ()</li>
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| 67 | <li class=fn>virtual void <a href="#rangeChange"><b>rangeChange</b></a> ()</li>
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| 68 | <li class=fn>virtual void <a href="#stepChange"><b>stepChange</b></a> ()</li>
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| 69 | </ul>
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| 70 | <hr><a name="details"></a><h2>Detailed Description</h2>
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| 71 |
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| 72 |
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| 73 | The QRangeControl class provides an integer value within a range.
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| 74 | <p>
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| 75 | <p> Although originally designed for the <a href="qscrollbar.html">QScrollBar</a> widget, the
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| 76 | QRangeControl can also be used in conjunction with other widgets
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| 77 | such as <a href="qslider.html">QSlider</a> and <a href="qspinbox.html">QSpinBox</a>. Here are the five main concepts in
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| 78 | the class:
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| 79 | <p> <ol type=1>
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| 80 | <p> <li> <em>Current value</em> The bounded integer that
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| 81 | QRangeControl maintains. <a href="#value">value</a>() returns it, and several
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| 82 | functions, including <a href="#setValue">setValue</a>(), set it.
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| 83 | <p> <li> <em>Minimum</em> The lowest value that value() can ever
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| 84 | return. Returned by <a href="#minValue">minValue</a>() and set by <a href="#setRange">setRange</a>() or one of the
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| 85 | constructors.
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| 86 | <p> <li> <em>Maximum</em> The highest value that value() can ever
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| 87 | return. Returned by <a href="#maxValue">maxValue</a>() and set by setRange() or one of the
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| 88 | constructors.
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| 89 | <p> <li> <em>Line step</em> The smaller of two natural steps that
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| 90 | QRangeControl provides and typically corresponds to the user
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| 91 | pressing an arrow key. The line step is returned by <a href="#lineStep">lineStep</a>()
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| 92 | and set using <a href="#setSteps">setSteps</a>(). The functions <a href="#addLine">addLine</a>() and
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| 93 | <a href="#subtractLine">subtractLine</a>() respectively increment and decrement the current
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| 94 | value by lineStep().
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| 95 | <p> <li> <em>Page step</em> The larger of two natural steps that
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| 96 | QRangeControl provides and typically corresponds to the user
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| 97 | pressing PageUp or PageDown. The page step is returned by
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| 98 | <a href="#pageStep">pageStep</a>() and set using setSteps(). The functions <a href="#addPage">addPage</a>() and
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| 99 | substractPage() respectively increment and decrement the current
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| 100 | value by pageStep().
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| 101 | <p> </ol>
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| 102 | <p> Unity (1) may be viewed as a third step size. <a href="#setValue">setValue</a>() lets you
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| 103 | set the current value to any integer in the allowed range, not
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| 104 | just <a href="#minValue">minValue</a>() + <em>n</em> * lineStep() for integer values of <em>n</em>.
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| 105 | Some widgets may allow the user to set any value at all; others
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| 106 | may just provide multiples of lineStep() or pageStep().
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| 107 | <p> QRangeControl provides three virtual functions that are well
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| 108 | suited for updating the on-screen representation of range controls
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| 109 | and emitting signals: <a href="#valueChange">valueChange</a>(), <a href="#rangeChange">rangeChange</a>() and
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| 110 | <a href="#stepChange">stepChange</a>().
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| 111 | <p> QRangeControl also provides a function called <a href="#bound">bound</a>() which lets
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| 112 | you force arbitrary integers to be within the allowed range of the
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| 113 | range control.
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| 114 | <p> We recommend that all widgets that inherit QRangeControl provide
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| 115 | at least a signal called valueChanged(); many widgets will want to
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| 116 | provide addStep(), <a href="#addPage">addPage</a>(), substractStep() and substractPage()
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| 117 | as slots.
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| 118 | <p> Note that you must use multiple inheritance if you plan to
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| 119 | implement a widget using QRangeControl because QRangeControl is
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| 120 | not derived from <a href="qwidget.html">QWidget</a>.
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| 121 | <p>See also <a href="misc.html">Miscellaneous Classes</a>.
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| 122 |
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| 123 | <hr><h2>Member Function Documentation</h2>
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| 124 | <h3 class=fn><a name="QRangeControl"></a>QRangeControl::QRangeControl ()
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| 125 | </h3>
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| 126 | Constructs a range control with a minimum value of 0, maximum
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| 127 | value of 99, line step of 1, page step of 10 and initial value 0.
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| 128 |
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| 129 | <h3 class=fn><a name="QRangeControl-2"></a>QRangeControl::QRangeControl ( int minValue, int maxValue, int lineStep, int pageStep, int value )
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| 130 | </h3>
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| 131 | Constructs a range control whose value can never be smaller than
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| 132 | <em>minValue</em> or greater than <em>maxValue</em>, whose line step size is
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| 133 | <em>lineStep</em> and page step size is <em>pageStep</em> and whose value is
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| 134 | initially <em>value</em> (which is guaranteed to be in range using
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| 135 | <a href="#bound">bound</a>()).
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| 136 |
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| 137 | <h3 class=fn><a name="~QRangeControl"></a>QRangeControl::~QRangeControl ()<tt> [virtual]</tt>
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| 138 | </h3>
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| 139 | Destroys the range control
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| 140 |
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| 141 | <h3 class=fn>void <a name="addLine"></a>QRangeControl::addLine ()
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| 142 | </h3>
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| 143 | Equivalent to <tt>setValue( value() + lineStep() )</tt>.
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| 144 | <p> If the value is changed, then <a href="#valueChange">valueChange</a>() is called.
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| 145 | <p> <p>See also <a href="#subtractLine">subtractLine</a>(), <a href="#addPage">addPage</a>(), and <a href="#setValue">setValue</a>().
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| 146 |
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| 147 | <h3 class=fn>void <a name="addPage"></a>QRangeControl::addPage ()
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| 148 | </h3>
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| 149 | Equivalent to <tt>setValue( value() + pageStep() )</tt>.
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| 150 | <p> If the value is changed, then <a href="#valueChange">valueChange</a>() is called.
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| 151 | <p> <p>See also <a href="#subtractPage">subtractPage</a>(), <a href="#addLine">addLine</a>(), and <a href="#setValue">setValue</a>().
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| 152 |
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| 153 | <h3 class=fn>int <a name="bound"></a>QRangeControl::bound ( int v ) const
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| 154 | </h3>
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| 155 | Forces the value <em>v</em> to be within the range from <a href="#minValue">minValue</a>() to
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| 156 | <a href="#maxValue">maxValue</a>() inclusive, and returns the result.
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| 157 | <p> This function is provided so that you can easily force other
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| 158 | numbers than <a href="#value">value</a>() into the allowed range. You do not need to
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| 159 | call it in order to use QRangeControl itself.
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| 160 | <p> <p>See also <a href="#setValue">setValue</a>(), <a href="#value">value</a>(), <a href="#minValue">minValue</a>(), and <a href="#maxValue">maxValue</a>().
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| 161 |
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| 162 | <h3 class=fn>void <a name="directSetValue"></a>QRangeControl::directSetValue ( int value )<tt> [protected]</tt>
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| 163 | </h3>
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| 164 | Sets the range control <em>value</em> directly without calling
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| 165 | <a href="#valueChange">valueChange</a>().
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| 166 | <p> Forces the new <em>value</em> to be within the legal range.
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| 167 | <p> You will rarely have to call this function. However, if you want
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| 168 | to change the range control's value inside the overloaded method
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| 169 | valueChange(), <a href="#setValue">setValue</a>() would call the function valueChange()
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| 170 | again. To avoid this recursion you must use <a href="#directSetValue">directSetValue</a>()
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| 171 | instead.
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| 172 | <p> <p>See also <a href="#setValue">setValue</a>().
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| 173 |
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| 174 | <h3 class=fn>int <a name="lineStep"></a>QRangeControl::lineStep () const
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| 175 | </h3>
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| 176 |
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| 177 | <p> Returns the line step.
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| 178 | <p> <p>See also <a href="#setSteps">setSteps</a>() and <a href="#pageStep">pageStep</a>().
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| 179 |
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| 180 | <h3 class=fn>int <a name="maxValue"></a>QRangeControl::maxValue () const
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| 181 | </h3>
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| 182 |
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| 183 | <p> Returns the maximum value of the range.
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| 184 | <p> <p>See also <a href="#setMaxValue">setMaxValue</a>(), <a href="#setRange">setRange</a>(), and <a href="#minValue">minValue</a>().
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| 185 |
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| 186 | <h3 class=fn>int <a name="minValue"></a>QRangeControl::minValue () const
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| 187 | </h3>
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| 188 |
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| 189 | <p> Returns the minimum value of the range.
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| 190 | <p> <p>See also <a href="#setMinValue">setMinValue</a>(), <a href="#setRange">setRange</a>(), and <a href="#maxValue">maxValue</a>().
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| 191 |
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| 192 | <h3 class=fn>int <a name="pageStep"></a>QRangeControl::pageStep () const
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| 193 | </h3>
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| 194 |
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| 195 | <p> Returns the page step.
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| 196 | <p> <p>See also <a href="#setSteps">setSteps</a>() and <a href="#lineStep">lineStep</a>().
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| 197 |
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| 198 | <h3 class=fn>int <a name="positionFromValue"></a>QRangeControl::positionFromValue ( int logical_val, int span ) const<tt> [protected]</tt>
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| 199 | </h3>
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| 200 | Converts <em>logical_val</em> to a pixel position. <a href="#minValue">minValue</a>() maps to 0,
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| 201 | <a href="#maxValue">maxValue</a>() maps to <em>span</em> and other values are distributed evenly
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| 202 | in-between.
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| 203 | <p> This function can handle the entire integer range without
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| 204 | overflow, providing <em>span</em> is <= 4096.
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| 205 | <p> Calling this method is useful when actually drawing a range
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| 206 | control such as a <a href="qscrollbar.html">QScrollBar</a> on-screen.
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| 207 | <p> <p>See also <a href="#valueFromPosition">valueFromPosition</a>().
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| 208 |
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| 209 | <h3 class=fn>int <a name="prevValue"></a>QRangeControl::prevValue () const<tt> [protected]</tt>
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| 210 | </h3>
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| 211 |
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| 212 | <p> Returns the previous value of the range control. "Previous value"
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| 213 | means the value before the last change occurred. Setting a new
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| 214 | range may affect the value, too, because the value is forced to be
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| 215 | inside the specified range. When the range control is initially
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| 216 | created, this is the same as <a href="#value">value</a>().
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| 217 | <p> <a href="#prevValue">prevValue</a>() can be outside the current legal range if a call to
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| 218 | <a href="#setRange">setRange</a>() causes the current value to change. For example, if the
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| 219 | range was [0, 1000] and the current value is 500, setRange(0, 400)
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| 220 | makes value() return 400 and prevValue() return 500.
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| 221 | <p> <p>See also <a href="#value">value</a>() and <a href="#setRange">setRange</a>().
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| 222 |
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| 223 | <h3 class=fn>void <a name="rangeChange"></a>QRangeControl::rangeChange ()<tt> [virtual protected]</tt>
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| 224 | </h3>
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| 225 | This virtual function is called whenever the range control's range
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| 226 | changes. You can reimplement it if you want to be notified when
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| 227 | the range changes. The default implementation does nothing.
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| 228 | <p> Note that this method is called after the range has changed.
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| 229 | <p> <p>See also <a href="#setRange">setRange</a>(), <a href="#valueChange">valueChange</a>(), and <a href="#stepChange">stepChange</a>().
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| 230 |
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| 231 | <p>Reimplemented in <a href="qdial.html#rangeChange">QDial</a>, <a href="qslider.html#rangeChange">QSlider</a>, and <a href="qspinbox.html#rangeChange">QSpinBox</a>.
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| 232 | <h3 class=fn>void <a name="setMaxValue"></a>QRangeControl::setMaxValue ( int maxVal )
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| 233 | </h3>
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| 234 | Sets the minimum value of the range to <em>maxVal</em>.
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| 235 | <p> If necessary, the <a href="#minValue">minValue</a>() is adjusted so that the range remains
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| 236 | valid.
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| 237 | <p> <p>See also <a href="#maxValue">maxValue</a>() and <a href="#setMinValue">setMinValue</a>().
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| 238 |
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| 239 | <h3 class=fn>void <a name="setMinValue"></a>QRangeControl::setMinValue ( int minVal )
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| 240 | </h3>
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| 241 | Sets the minimum value of the range to <em>minVal</em>.
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| 242 | <p> If necessary, the <a href="#maxValue">maxValue</a>() is adjusted so that the range remains
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| 243 | valid.
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| 244 | <p> <p>See also <a href="#minValue">minValue</a>() and <a href="#setMaxValue">setMaxValue</a>().
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| 245 |
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| 246 | <h3 class=fn>void <a name="setRange"></a>QRangeControl::setRange ( int minValue, int maxValue )
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| 247 | </h3>
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| 248 | Sets the range control's minimum value to <em>minValue</em> and its
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| 249 | maximum value to <em>maxValue</em>.
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| 250 | <p> Calls the virtual <a href="#rangeChange">rangeChange</a>() function if one or both of the new
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| 251 | minimum and maximum values are different from the previous
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| 252 | setting. Calls the virtual <a href="#valueChange">valueChange</a>() function if the current
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| 253 | value is adjusted because it was outside the new range.
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| 254 | <p> If <em>maxValue</em> is smaller than <em>minValue</em>, <em>minValue</em> becomes
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| 255 | the only legal value.
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| 256 | <p> <p>See also <a href="#minValue">minValue</a>() and <a href="#maxValue">maxValue</a>().
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| 257 |
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| 258 | <p>Examples: <a href="listbox-example.html#x1441">listbox/listbox.cpp</a>, <a href="tutorial1-12.html#x2387">t12/lcdrange.cpp</a>, <a href="tutorial1-05.html#x2315">t5/main.cpp</a>, <a href="tutorial1-06.html#x2325">t6/main.cpp</a>, <a href="tutorial1-08.html#x2334">t8/lcdrange.cpp</a>, and <a href="xform-example.html#x1250">xform/xform.cpp</a>.
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| 259 | <h3 class=fn>void <a name="setSteps"></a>QRangeControl::setSteps ( int lineStep, int pageStep )
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| 260 | </h3>
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| 261 | Sets the range's line step to <em>lineStep</em> and page step to <em>pageStep</em>.
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| 262 | <p> Calls the virtual <a href="#stepChange">stepChange</a>() function if the new line step
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| 263 | or page step are different from the previous settings.
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| 264 | <p> <p>See also <a href="#lineStep">lineStep</a>(), <a href="#pageStep">pageStep</a>(), and <a href="#setRange">setRange</a>().
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| 265 |
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| 266 | <h3 class=fn>void <a name="setValue"></a>QRangeControl::setValue ( int value )
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| 267 | </h3>
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| 268 | Sets the range control's value to <em>value</em> and forces it to be
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| 269 | within the legal range.
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| 270 | <p> Calls the virtual <a href="#valueChange">valueChange</a>() function if the new value is
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| 271 | different from the previous value. The old value can still be
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| 272 | retrieved using <a href="#prevValue">prevValue</a>().
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| 273 | <p> <p>See also <a href="#value">value</a>().
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| 274 |
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| 275 | <h3 class=fn>void <a name="stepChange"></a>QRangeControl::stepChange ()<tt> [virtual protected]</tt>
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| 276 | </h3>
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| 277 | This virtual function is called whenever the range control's
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| 278 | line or page step settings change. You can reimplement it if you
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| 279 | want to be notified when the step changes. The default
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| 280 | implementation does nothing.
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| 281 | <p> Note that this method is called after a step setting has changed.
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| 282 | <p> <p>See also <a href="#setSteps">setSteps</a>(), <a href="#rangeChange">rangeChange</a>(), and <a href="#valueChange">valueChange</a>().
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| 283 |
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| 284 | <h3 class=fn>void <a name="subtractLine"></a>QRangeControl::subtractLine ()
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| 285 | </h3>
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| 286 | Equivalent to <tt>setValue( value() - lineStep() )</tt>.
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| 287 | <p> If the value is changed, then <a href="#valueChange">valueChange</a>() is called.
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| 288 | <p> <p>See also <a href="#addLine">addLine</a>(), <a href="#subtractPage">subtractPage</a>(), and <a href="#setValue">setValue</a>().
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| 289 |
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| 290 | <h3 class=fn>void <a name="subtractPage"></a>QRangeControl::subtractPage ()
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| 291 | </h3>
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| 292 | Equivalent to <tt>setValue( value() - pageStep() )</tt>.
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| 293 | <p> If the value is changed, then <a href="#valueChange">valueChange</a>() is called.
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| 294 | <p> <p>See also <a href="#addPage">addPage</a>(), <a href="#subtractLine">subtractLine</a>(), and <a href="#setValue">setValue</a>().
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| 295 |
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| 296 | <h3 class=fn>int <a name="value"></a>QRangeControl::value () const
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| 297 | </h3>
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| 298 |
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| 299 | <p> Returns the current range control value. This is guaranteed to be
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| 300 | within the range [minValue(), <a href="#maxValue">maxValue</a>()].
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| 301 | <p> <p>See also <a href="#setValue">setValue</a>() and <a href="#prevValue">prevValue</a>().
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| 302 |
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| 303 | <h3 class=fn>void <a name="valueChange"></a>QRangeControl::valueChange ()<tt> [virtual protected]</tt>
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| 304 | </h3>
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| 305 | This virtual function is called whenever the range control value
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| 306 | changes. You can reimplement it if you want to be notified when
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| 307 | the value changes. The default implementation does nothing.
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| 308 | <p> Note that this method is called after the value has changed. The
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| 309 | previous value can be retrieved using <a href="#prevValue">prevValue</a>().
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| 310 | <p> <p>See also <a href="#setValue">setValue</a>(), <a href="#addPage">addPage</a>(), <a href="#subtractPage">subtractPage</a>(), <a href="#addLine">addLine</a>(), <a href="#subtractLine">subtractLine</a>(), <a href="#rangeChange">rangeChange</a>(), and <a href="#stepChange">stepChange</a>().
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| 311 |
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| 312 | <p>Reimplemented in <a href="qdial.html#valueChange">QDial</a>, <a href="qslider.html#valueChange">QSlider</a>, and <a href="qspinbox.html#valueChange">QSpinBox</a>.
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| 313 | <h3 class=fn>int <a name="valueFromPosition"></a>QRangeControl::valueFromPosition ( int pos, int span ) const<tt> [protected]</tt>
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| 314 | </h3>
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| 315 | Converts the pixel position <em>pos</em> to a value. 0 maps to
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| 316 | <a href="#minValue">minValue</a>(), <em>span</em> maps to <a href="#maxValue">maxValue</a>() and other values are
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| 317 | distributed evenly in-between.
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| 318 | <p> This function can handle the entire integer range without
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| 319 | overflow.
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| 320 | <p> Calling this method is useful if you actually implemented a range
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| 321 | control widget such as <a href="qscrollbar.html">QScrollBar</a> and want to handle mouse press
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| 322 | events. This function then maps screen coordinates to the logical
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| 323 | values.
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| 324 | <p> <p>See also <a href="#positionFromValue">positionFromValue</a>().
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| 325 |
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| 326 | <!-- eof -->
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| 327 | <hr><p>
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| 328 | This file is part of the <a href="index.html">Qt toolkit</a>.
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| 329 | Copyright © 1995-2007
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| 330 | <a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
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| 331 | <table width=100% cellspacing=0 border=0><tr>
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| 332 | <td>Copyright © 2007
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| 333 | <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
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| 334 | <td align=right><div align=right>Qt 3.3.8</div>
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| 335 | </table></div></address></body>
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| 336 | </html>
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