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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>QDirectPainter Class Reference</h1>
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| 33 |
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| 34 | <p>The QDirectPainter class provides direct access to the video hardware.
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| 35 | <a href="#details">More...</a>
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| 36 | <p><tt>#include <<a href="qdirectpainter_qws-h.html">qdirectpainter_qws.h</a>></tt>
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| 37 | <p>Inherits <a href="qpainter.html">QPainter</a>.
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| 38 | <p><a href="qdirectpainter-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="#QDirectPainter"><b>QDirectPainter</b></a> ( const QWidget * w )</li>
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| 42 | <li class=fn><a href="#~QDirectPainter"><b>~QDirectPainter</b></a> ()</li>
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| 43 | <li class=fn>uchar * <a href="#frameBuffer"><b>frameBuffer</b></a> ()</li>
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| 44 | <li class=fn>int <a href="#lineStep"><b>lineStep</b></a> ()</li>
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| 45 | <li class=fn>int <a href="#transformOrientation"><b>transformOrientation</b></a> ()</li>
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| 46 | <li class=fn>int <a href="#numRects"><b>numRects</b></a> () const</li>
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| 47 | <li class=fn>const QRect & <a href="#rect"><b>rect</b></a> ( int i ) const</li>
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| 48 | <li class=fn>QRegion <a href="#region"><b>region</b></a> () const</li>
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| 49 | <li class=fn>int <a href="#depth"><b>depth</b></a> () const</li>
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| 50 | <li class=fn>int <a href="#width"><b>width</b></a> () const</li>
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| 51 | <li class=fn>int <a href="#height"><b>height</b></a> () const</li>
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| 52 | <li class=fn>int <a href="#xOffset"><b>xOffset</b></a> () const</li>
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| 53 | <li class=fn>int <a href="#yOffset"><b>yOffset</b></a> () const</li>
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| 54 | <li class=fn>QPoint <a href="#offset"><b>offset</b></a> () const</li>
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| 55 | <li class=fn>QSize <a href="#size"><b>size</b></a> () const</li>
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| 56 | <li class=fn>void <a href="#setAreaChanged"><b>setAreaChanged</b></a> ( const QRect & r )</li>
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| 57 | </ul>
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| 58 | <hr><a name="details"></a><h2>Detailed Description</h2>
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| 59 |
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| 60 |
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| 61 | The QDirectPainter class provides direct access to the video hardware.
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| 62 | <p>
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| 63 | <p> Only available in Qt/Embedded.
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| 64 | <p> When the hardware is known and well defined, as is often the case
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| 65 | with software for embedded devices, it may be useful to manipulate
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| 66 | the underlying video hardware directly. In order to do this in a
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| 67 | way that is co-operative with other applications, you must lock
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| 68 | the video hardware for exclusive use for a small time while you
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| 69 | write to it, and you must know the clipping region which is
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| 70 | allocated to a widget.
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| 71 | <p> QDirectPainter provides this functionality.
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| 72 | <p> In the simplest case, you make a QDirectPainter on a widget and
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| 73 | then, observing the clip region, perform some platform-specific
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| 74 | operation. For example:
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| 75 | <pre>
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| 76 | void MyWidget::updatePlatformGraphics()
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| 77 | {
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| 78 | QDirectPainter dp( this );
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| 79 | for ( int i = 0; i < dp.numRects; i++ ) {
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| 80 | const <a href="qrect.html">QRect</a>& clip = dp.<a href="#rect">rect</a>(i);
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| 81 | ... // platform specific operation
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| 82 | }
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| 83 | }
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| 84 | </pre>
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| 85 |
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| 86 | <p> The platform-specific code has access to the display, but should
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| 87 | only modify graphics in the rectangles specified by <a href="#numRects">numRects</a>() and
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| 88 | <a href="#rect">rect</a>(). Note that these rectangles are relative to the entire
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| 89 | display.
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| 90 | <p> The <a href="#offset">offset</a>() function returns the position of the widget relative
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| 91 | to the entire display, allowing you to offset platform-specific
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| 92 | operations appropriately. The <a href="#xOffset">xOffset</a>() and <a href="#yOffset">yOffset</a>() functions
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| 93 | merely return the component values of offset().
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| 94 | <p> For simple frame-buffer hardware, the <a href="#frameBuffer">frameBuffer</a>(), <a href="#lineStep">lineStep</a>(),
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| 95 | and <a href="#depth">depth</a>() functions provide basic access, though some hardware
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| 96 | configurations are insufficiently specified by such simple
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| 97 | parameters.
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| 98 | <p> Note that while a QDirectPainter exists, the entire Qt/Embedded
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| 99 | window system is locked from use by other applications. Always
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| 100 | construct the QDirectPainter as an auto (stack) variable, and be
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| 101 | very careful to write robust and stable code within its scope.
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| 102 | <p>See also <a href="graphics.html">Graphics Classes</a>.
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| 103 |
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| 104 | <hr><h2>Member Function Documentation</h2>
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| 105 | <h3 class=fn><a name="QDirectPainter"></a>QDirectPainter::QDirectPainter ( const <a href="qwidget.html">QWidget</a> * w )
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| 106 | </h3>
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| 107 | Construct a direct painter on <em>w</em>. The display is locked and the
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| 108 | mouse cursor is hidden if it is above <em>w</em>.
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| 109 |
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| 110 | <h3 class=fn><a name="~QDirectPainter"></a>QDirectPainter::~QDirectPainter ()
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| 111 | </h3>
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| 112 | Destroys the direct painter. The mouse cursor is revealed if
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| 113 | necessary and the display is unlocked.
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| 114 |
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| 115 | <h3 class=fn>int <a name="depth"></a>QDirectPainter::depth () const
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| 116 | </h3>
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| 117 | Returns the bit-depth of the display.
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| 118 |
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| 119 | <h3 class=fn>uchar * <a name="frameBuffer"></a>QDirectPainter::frameBuffer ()
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| 120 | </h3>
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| 121 | Returns a pointer to the framebuffer memory if available.
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| 122 |
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| 123 | <h3 class=fn>int <a name="height"></a>QDirectPainter::height () const
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| 124 | </h3>
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| 125 | Returns the height of the widget drawn upon.
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| 126 |
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| 127 | <h3 class=fn>int <a name="lineStep"></a>QDirectPainter::lineStep ()
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| 128 | </h3>
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| 129 | Returns the spacing in bytes from one framebuffer line to the
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| 130 | next.
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| 131 |
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| 132 | <h3 class=fn>int <a name="numRects"></a>QDirectPainter::numRects () const
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| 133 | </h3>
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| 134 | Returns the number of rectangles in the drawable region.
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| 135 | <p> <p>See also <a href="#rect">rect</a>() and <a href="#region">region</a>().
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| 136 |
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| 137 | <h3 class=fn><a href="qpoint.html">QPoint</a> <a name="offset"></a>QDirectPainter::offset () const
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| 138 | </h3>
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| 139 | Returns the position of the widget relative to the entire display.
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| 140 |
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| 141 | <h3 class=fn>const <a href="qrect.html">QRect</a> & <a name="rect"></a>QDirectPainter::rect ( int i ) const
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| 142 | </h3>
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| 143 | Returns a reference to rectangle <em>i</em> of the drawable region.
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| 144 | Valid values for <em>i</em> are 0..<a href="#numRects">numRects</a>()-1.
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| 145 | <p> <p>See also <a href="#region">region</a>().
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| 146 |
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| 147 | <h3 class=fn><a href="qregion.html">QRegion</a> <a name="region"></a>QDirectPainter::region () const
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| 148 | </h3>
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| 149 | Returns the region of the framebuffer which represents the exposed
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| 150 | area of the widget being painted on. Note that this may be a sub-area of
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| 151 | the clip region, because of child widgets and overlapping cousin widgets.
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| 152 | <p> <p>See also <a href="#numRects">numRects</a>() and <a href="#rect">rect</a>().
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| 153 |
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| 154 | <h3 class=fn>void <a name="setAreaChanged"></a>QDirectPainter::setAreaChanged ( const <a href="qrect.html">QRect</a> & r )
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| 155 | </h3>
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| 156 | Sets the area changed by the transaction to <em>r</em>. By default, the
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| 157 | entire widget is assumed to have changed. The area changed is only
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| 158 | used by some graphics drivers, so often calling this function for
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| 159 | a smaller area will make no difference to performance.
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| 160 |
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| 161 | <h3 class=fn><a href="qsize.html">QSize</a> <a name="size"></a>QDirectPainter::size () const
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| 162 | </h3>
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| 163 | Returns the size of the widget drawn upon.
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| 164 | <p> <p>See also <a href="#width">width</a>() and <a href="#height">height</a>().
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| 165 |
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| 166 | <h3 class=fn>int <a name="transformOrientation"></a>QDirectPainter::transformOrientation ()
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| 167 | </h3>
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| 168 | Returns a number that signifies the orientation of the
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| 169 | framebuffer.
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| 170 | <center><table cellpadding="4" cellspacing="2" border="0">
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| 171 | <tr bgcolor="#f0f0f0"> <td valign="top" colspan="1" rowspan="1"> 0 <td valign="top" colspan="1" rowspan="1"> no rotation
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| 172 | <tr bgcolor="#d0d0d0"> <td valign="top" colspan="1" rowspan="1"> 1 <td valign="top" colspan="1" rowspan="1"> 90 degrees rotation
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| 173 | <tr bgcolor="#f0f0f0"> <td valign="top" colspan="1" rowspan="1"> 2 <td valign="top" colspan="1" rowspan="1"> 180 degrees rotation
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| 174 | <tr bgcolor="#d0d0d0"> <td valign="top" colspan="1" rowspan="1"> 3 <td valign="top" colspan="1" rowspan="1"> 270 degrees rotation
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| 175 | </table></center>
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| 176 |
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| 177 | <h3 class=fn>int <a name="width"></a>QDirectPainter::width () const
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| 178 | </h3>
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| 179 | Returns the width of the widget drawn upon.
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| 180 |
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| 181 | <h3 class=fn>int <a name="xOffset"></a>QDirectPainter::xOffset () const
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| 182 | </h3>
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| 183 | Returns the X-position of the widget relative to the entire
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| 184 | display.
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| 185 |
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| 186 | <h3 class=fn>int <a name="yOffset"></a>QDirectPainter::yOffset () const
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| 187 | </h3>
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| 188 | Returns the Y-position of the widget relative to the entire
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| 189 | display.
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| 190 |
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| 191 | <!-- eof -->
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| 192 | <hr><p>
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| 193 | This file is part of the <a href="index.html">Qt toolkit</a>.
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| 194 | Copyright © 1995-2007
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| 195 | <a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
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| 196 | <table width=100% cellspacing=0 border=0><tr>
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| 197 | <td>Copyright © 2007
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| 198 | <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
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| 199 | <td align=right><div align=right>Qt 3.3.8</div>
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| 200 | </table></div></address></body>
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| 201 | </html>
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