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<td >Qt 5.12</td><td ><a href="qtcore-index.html">Qt Core</a></td><td ><a href="qtcore-module.html">C++ Classes</a></td><td >QLine</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qtcore-index.html">Qt 5.12.6 Reference Documentation</a></td>
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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#related-non-members">Related Non-Members</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">QLine Class</h1>
<!-- $$$QLine-brief -->
<p>The <a href="qline.html">QLine</a> class provides a two-dimensional vector using integer precision. <a href="#details">More...</a></p>
<!-- @@@QLine -->
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QLine></span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += core</td></tr></table></div><ul>
<li><a href="qline-members.html">List of all members, including inherited members</a></li>
</ul>
<a name="public-functions"></a>
<h2 id="public-functions">Public Functions</h2>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qline.html#QLine">QLine</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qline.html#QLine-1">QLine</a></b>(const QPoint &<i>p1</i>, const QPoint &<i>p2</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qline.html#QLine-2">QLine</a></b>(int <i>x1</i>, int <i>y1</i>, int <i>x2</i>, int <i>y2</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QPoint </td><td class="memItemRight bottomAlign"><b><a href="qline.html#p1">p1</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QPoint </td><td class="memItemRight bottomAlign"><b><a href="qline.html#p2">p2</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qline.html#x1">x1</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qline.html#x2">x2</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qline.html#y1">y1</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qline.html#y2">y2</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QPoint </td><td class="memItemRight bottomAlign"><b><a href="qline.html#center">center</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qline.html#dx">dx</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qline.html#dy">dy</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qline.html#isNull">isNull</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qline.html#setP1">setP1</a></b>(const QPoint &<i>p1</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qline.html#setP2">setP2</a></b>(const QPoint &<i>p2</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qline.html#setLine">setLine</a></b>(int <i>x1</i>, int <i>y1</i>, int <i>x2</i>, int <i>y2</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qline.html#setPoints">setPoints</a></b>(const QPoint &<i>p1</i>, const QPoint &<i>p2</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qline.html#translate">translate</a></b>(const QPoint &<i>offset</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qline.html#translate-1">translate</a></b>(int <i>dx</i>, int <i>dy</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QLine </td><td class="memItemRight bottomAlign"><b><a href="qline.html#translated">translated</a></b>(const QPoint &<i>offset</i>) const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QLine </td><td class="memItemRight bottomAlign"><b><a href="qline.html#translated-1">translated</a></b>(int <i>dx</i>, int <i>dy</i>) const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qline.html#operator-not-eq">operator!=</a></b>(const QLine &<i>line</i>) const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qline.html#operator-eq-eq">operator==</a></b>(const QLine &<i>line</i>) const</td></tr>
</table></div>
<a name="related-non-members"></a>
<h2 id="related-non-members">Related Non-Members</h2>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> QDataStream &</td><td class="memItemRight bottomAlign"><b><a href="qline.html#operator-lt-lt">operator<<</a></b>(QDataStream &<i>stream</i>, const QLine &<i>line</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QDataStream &</td><td class="memItemRight bottomAlign"><b><a href="qline.html#operator-gt-gt">operator>></a></b>(QDataStream &<i>stream</i>, QLine &<i>line</i>)</td></tr>
</table></div>
<a name="details"></a>
<!-- $$$QLine-description -->
<div class="descr">
<h2 id="details">Detailed Description</h2>
<p>The <a href="qline.html">QLine</a> class provides a two-dimensional vector using integer precision.</p>
<p>A <a href="qline.html">QLine</a> describes a finite length line (or a line segment) on a two-dimensional surface. The start and end points of the line are specified using integer point accuracy for coordinates. Use the <a href="qlinef.html">QLineF</a> constructor to retrieve a floating point copy.</p>
<div class="table"><table class="generic">
<tr valign="top" class="odd"><td ><img src="images/qline-point.png" alt="" /></td><td ><img src="images/qline-coordinates.png" alt="" /></td></tr>
</table></div>
<p>The positions of the line's start and end points can be retrieved using the <a href="qline.html#p1">p1</a>(), <a href="qline.html#x1">x1</a>(), <a href="qline.html#y1">y1</a>(), <a href="qline.html#p2">p2</a>(), <a href="qline.html#x2">x2</a>(), and <a href="qline.html#y2">y2</a>() functions. The <a href="qline.html#dx">dx</a>() and <a href="qline.html#dy">dy</a>() functions return the horizontal and vertical components of the line. Use <a href="qline.html#isNull">isNull</a>() to determine whether the <a href="qline.html">QLine</a> represents a valid line or a null line.</p>
<p>Finally, the line can be translated a given offset using the <a href="qline.html#translate">translate</a>() function.</p>
</div>
<p><b>See also </b><a href="qlinef.html">QLineF</a>, <a href="../qtgui/qpolygon.html">QPolygon</a>, and <a href="qrect.html">QRect</a>.</p>
<!-- @@@QLine -->
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$QLine[overload1]$$$QLine -->
<h3 class="fn" id="QLine"><a name="QLine"></a>QLine::<span class="name">QLine</span>()</h3>
<p>Constructs a null line.</p>
<!-- @@@QLine -->
<!-- $$$QLine$$$QLineconstQPoint&constQPoint& -->
<h3 class="fn" id="QLine-1"><a name="QLine-1"></a>QLine::<span class="name">QLine</span>(const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>p1</i>, const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>p2</i>)</h3>
<p>Constructs a line object that represents the line between <i>p1</i> and <i>p2</i>.</p>
<!-- @@@QLine -->
<!-- $$$QLine$$$QLineintintintint -->
<h3 class="fn" id="QLine-2"><a name="QLine-2"></a>QLine::<span class="name">QLine</span>(<span class="type">int</span> <i>x1</i>, <span class="type">int</span> <i>y1</i>, <span class="type">int</span> <i>x2</i>, <span class="type">int</span> <i>y2</i>)</h3>
<p>Constructs a line object that represents the line between (<i>x1</i>, <i>y1</i>) and (<i>x2</i>, <i>y2</i>).</p>
<!-- @@@QLine -->
<!-- $$$p1[overload1]$$$p1 -->
<h3 class="fn" id="p1"><a name="p1"></a><span class="type"><a href="qpoint.html">QPoint</a></span> QLine::<span class="name">p1</span>() const</h3>
<p>Returns the line's start point.</p>
<p><b>See also </b><a href="qline.html#setP1">setP1</a>(), <a href="qline.html#x1">x1</a>(), <a href="qline.html#y1">y1</a>(), and <a href="qline.html#p2">p2</a>().</p>
<!-- @@@p1 -->
<!-- $$$p2[overload1]$$$p2 -->
<h3 class="fn" id="p2"><a name="p2"></a><span class="type"><a href="qpoint.html">QPoint</a></span> QLine::<span class="name">p2</span>() const</h3>
<p>Returns the line's end point.</p>
<p><b>See also </b><a href="qline.html#setP2">setP2</a>(), <a href="qline.html#x2">x2</a>(), <a href="qline.html#y2">y2</a>(), and <a href="qline.html#p1">p1</a>().</p>
<!-- @@@p2 -->
<!-- $$$x1[overload1]$$$x1 -->
<h3 class="fn" id="x1"><a name="x1"></a><span class="type">int</span> QLine::<span class="name">x1</span>() const</h3>
<p>Returns the x-coordinate of the line's start point.</p>
<p><b>See also </b><a href="qline.html#p1">p1</a>().</p>
<!-- @@@x1 -->
<!-- $$$x2[overload1]$$$x2 -->
<h3 class="fn" id="x2"><a name="x2"></a><span class="type">int</span> QLine::<span class="name">x2</span>() const</h3>
<p>Returns the x-coordinate of the line's end point.</p>
<p><b>See also </b><a href="qline.html#p2">p2</a>().</p>
<!-- @@@x2 -->
<!-- $$$y1[overload1]$$$y1 -->
<h3 class="fn" id="y1"><a name="y1"></a><span class="type">int</span> QLine::<span class="name">y1</span>() const</h3>
<p>Returns the y-coordinate of the line's start point.</p>
<p><b>See also </b><a href="qline.html#p1">p1</a>().</p>
<!-- @@@y1 -->
<!-- $$$y2[overload1]$$$y2 -->
<h3 class="fn" id="y2"><a name="y2"></a><span class="type">int</span> QLine::<span class="name">y2</span>() const</h3>
<p>Returns the y-coordinate of the line's end point.</p>
<p><b>See also </b><a href="qline.html#p2">p2</a>().</p>
<!-- @@@y2 -->
<!-- $$$center[overload1]$$$center -->
<h3 class="fn" id="center"><a name="center"></a><span class="type"><a href="qpoint.html">QPoint</a></span> QLine::<span class="name">center</span>() const</h3>
<p>Returns the center point of this line. This is equivalent to (<a href="qline.html#p1">p1</a>() + <a href="qline.html#p2">p2</a>()) / 2, except it will never overflow.</p>
<p>This function was introduced in Qt 5.8.</p>
<!-- @@@center -->
<!-- $$$dx[overload1]$$$dx -->
<h3 class="fn" id="dx"><a name="dx"></a><span class="type">int</span> QLine::<span class="name">dx</span>() const</h3>
<p>Returns the horizontal component of the line's vector.</p>
<p><b>See also </b><a href="qline.html#dy">dy</a>().</p>
<!-- @@@dx -->
<!-- $$$dy[overload1]$$$dy -->
<h3 class="fn" id="dy"><a name="dy"></a><span class="type">int</span> QLine::<span class="name">dy</span>() const</h3>
<p>Returns the vertical component of the line's vector.</p>
<p><b>See also </b><a href="qline.html#dx">dx</a>().</p>
<!-- @@@dy -->
<!-- $$$isNull[overload1]$$$isNull -->
<h3 class="fn" id="isNull"><a name="isNull"></a><span class="type">bool</span> QLine::<span class="name">isNull</span>() const</h3>
<p>Returns <code>true</code> if the line is not set up with valid start and end point; otherwise returns <code>false</code>.</p>
<!-- @@@isNull -->
<!-- $$$setP1[overload1]$$$setP1constQPoint& -->
<h3 class="fn" id="setP1"><a name="setP1"></a><span class="type">void</span> QLine::<span class="name">setP1</span>(const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>p1</i>)</h3>
<p>Sets the starting point of this line to <i>p1</i>.</p>
<p>This function was introduced in Qt 4.4.</p>
<p><b>See also </b><a href="qline.html#setP2">setP2</a>() and <a href="qline.html#p1">p1</a>().</p>
<!-- @@@setP1 -->
<!-- $$$setP2[overload1]$$$setP2constQPoint& -->
<h3 class="fn" id="setP2"><a name="setP2"></a><span class="type">void</span> QLine::<span class="name">setP2</span>(const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>p2</i>)</h3>
<p>Sets the end point of this line to <i>p2</i>.</p>
<p>This function was introduced in Qt 4.4.</p>
<p><b>See also </b><a href="qline.html#setP1">setP1</a>() and <a href="qline.html#p2">p2</a>().</p>
<!-- @@@setP2 -->
<!-- $$$setLine[overload1]$$$setLineintintintint -->
<h3 class="fn" id="setLine"><a name="setLine"></a><span class="type">void</span> QLine::<span class="name">setLine</span>(<span class="type">int</span> <i>x1</i>, <span class="type">int</span> <i>y1</i>, <span class="type">int</span> <i>x2</i>, <span class="type">int</span> <i>y2</i>)</h3>
<p>Sets this line to the start in <i>x1</i>, <i>y1</i> and end in <i>x2</i>, <i>y2</i>.</p>
<p>This function was introduced in Qt 4.4.</p>
<p><b>See also </b><a href="qline.html#setP1">setP1</a>(), <a href="qline.html#setP2">setP2</a>(), <a href="qline.html#p1">p1</a>(), and <a href="qline.html#p2">p2</a>().</p>
<!-- @@@setLine -->
<!-- $$$setPoints[overload1]$$$setPointsconstQPoint&constQPoint& -->
<h3 class="fn" id="setPoints"><a name="setPoints"></a><span class="type">void</span> QLine::<span class="name">setPoints</span>(const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>p1</i>, const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>p2</i>)</h3>
<p>Sets the start point of this line to <i>p1</i> and the end point of this line to <i>p2</i>.</p>
<p>This function was introduced in Qt 4.4.</p>
<p><b>See also </b><a href="qline.html#setP1">setP1</a>(), <a href="qline.html#setP2">setP2</a>(), <a href="qline.html#p1">p1</a>(), and <a href="qline.html#p2">p2</a>().</p>
<!-- @@@setPoints -->
<!-- $$$translate[overload1]$$$translateconstQPoint& -->
<h3 class="fn" id="translate"><a name="translate"></a><span class="type">void</span> QLine::<span class="name">translate</span>(const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>offset</i>)</h3>
<p>Translates this line by the given <i>offset</i>.</p>
<!-- @@@translate -->
<!-- $$$translate$$$translateintint -->
<h3 class="fn" id="translate-1"><a name="translate-1"></a><span class="type">void</span> QLine::<span class="name">translate</span>(<span class="type">int</span> <i>dx</i>, <span class="type">int</span> <i>dy</i>)</h3>
<p>This is an overloaded function.</p>
<p>Translates this line the distance specified by <i>dx</i> and <i>dy</i>.</p>
<!-- @@@translate -->
<!-- $$$translated[overload1]$$$translatedconstQPoint& -->
<h3 class="fn" id="translated"><a name="translated"></a><span class="type"><a href="qline.html#QLine">QLine</a></span> QLine::<span class="name">translated</span>(const <span class="type"><a href="qpoint.html">QPoint</a></span> &<i>offset</i>) const</h3>
<p>Returns this line translated by the given <i>offset</i>.</p>
<p>This function was introduced in Qt 4.4.</p>
<!-- @@@translated -->
<!-- $$$translated$$$translatedintint -->
<h3 class="fn" id="translated-1"><a name="translated-1"></a><span class="type"><a href="qline.html#QLine">QLine</a></span> QLine::<span class="name">translated</span>(<span class="type">int</span> <i>dx</i>, <span class="type">int</span> <i>dy</i>) const</h3>
<p>This is an overloaded function.</p>
<p>Returns this line translated the distance specified by <i>dx</i> and <i>dy</i>.</p>
<p>This function was introduced in Qt 4.4.</p>
<!-- @@@translated -->
<!-- $$$operator!=[overload1]$$$operator!=constQLine& -->
<h3 class="fn" id="operator-not-eq"><a name="operator-not-eq"></a><span class="type">bool</span> QLine::<span class="name">operator!=</span>(const <span class="type"><a href="qline.html#QLine">QLine</a></span> &<i>line</i>) const</h3>
<p>Returns <code>true</code> if the given <i>line</i> is not the same as <i>this</i> line.</p>
<p>A line is different from another line if any of their start or end points differ, or the internal order of the points is different.</p>
<!-- @@@operator!= -->
<!-- $$$operator==[overload1]$$$operator==constQLine& -->
<h3 class="fn" id="operator-eq-eq"><a name="operator-eq-eq"></a><span class="type">bool</span> QLine::<span class="name">operator==</span>(const <span class="type"><a href="qline.html#QLine">QLine</a></span> &<i>line</i>) const</h3>
<p>Returns <code>true</code> if the given <i>line</i> is the same as <i>this</i> line.</p>
<p>A line is identical to another line if the start and end points are identical, and the internal order of the points is the same.</p>
<!-- @@@operator== -->
</div>
<div class="relnonmem">
<h2>Related Non-Members</h2>
<!-- $$$operator<<[overload1]$$$operator<<QDataStream&constQLine& -->
<h3 class="fn" id="operator-lt-lt"><a name="operator-lt-lt"></a><span class="type"><a href="qdatastream.html">QDataStream</a></span> &<span class="name">operator<<</span>(<span class="type"><a href="qdatastream.html">QDataStream</a></span> &<i>stream</i>, const <span class="type"><a href="qline.html#QLine">QLine</a></span> &<i>line</i>)</h3>
<p>Writes the given <i>line</i> to the given <i>stream</i> and returns a reference to the stream.</p>
<p><b>See also </b><a href="datastreamformat.html">Serializing Qt Data Types</a>.</p>
<!-- @@@operator<< -->
<!-- $$$operator>>[overload1]$$$operator>>QDataStream&QLine& -->
<h3 class="fn" id="operator-gt-gt"><a name="operator-gt-gt"></a><span class="type"><a href="qdatastream.html">QDataStream</a></span> &<span class="name">operator>></span>(<span class="type"><a href="qdatastream.html">QDataStream</a></span> &<i>stream</i>, <span class="type"><a href="qline.html#QLine">QLine</a></span> &<i>line</i>)</h3>
<p>Reads a line from the given <i>stream</i> into the given <i>line</i> and returns a reference to the stream.</p>
<p><b>See also </b><a href="datastreamformat.html">Serializing Qt Data Types</a>.</p>
<!-- @@@operator>> -->
</div>
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