<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- stylesheet.qdoc --> <title>Customizing Qt Widgets Using Style Sheets | Qt Widgets 5.12.6</title> <link rel="stylesheet" type="text/css" href="style/offline-simple.css" /> <script type="text/javascript"> document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css"); // loading style sheet breaks anchors that were jumped to before // so force jumping to anchor again setTimeout(function() { var anchor = location.hash; // need to jump to different anchor first (e.g. none) location.hash = "#"; setTimeout(function() { location.hash = anchor; }, 0); }, 0); </script> </head> <body> <div class="header" id="qtdocheader"> <div class="main"> <div class="main-rounded"> <div class="navigationbar"> <table><tr> <td >Qt 5.12</td><td ><a href="qtwidgets-index.html">Qt Widgets</a></td><td >Customizing Qt Widgets Using Style Sheets</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right"><a href="qtwidgets-index.html">Qt 5.12.6 Reference Documentation</a></td> </tr></table> </div> </div> <div class="content"> <div class="line"> <div class="content mainContent"> <link rel="prev" href="stylesheet-designer.html" /> <link rel="next" href="stylesheet-reference.html" /> <p class="naviNextPrevious headerNavi"> <a class="prevPage" href="stylesheet-designer.html">Qt Designer Integration</a> <span class="naviSeparator"> ◦ </span> <a class="nextPage" href="stylesheet-reference.html">Qt Style Sheets Reference</a> </p><p/> <div class="sidebar"> <div class="toc"> <h3><a name="toc">Contents</a></h3> <ul> <li class="level1"><a href="#the-box-model">The Box Model</a></li> <li class="level1"><a href="#sub-controls">Sub-controls</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">Customizing Qt Widgets Using Style Sheets</h1> <span class="subtitle"></span> <!-- $$$stylesheet-customizing.html-description --> <div class="descr"> <a name="details"></a> <p>When using style sheets, every widget is treated as a box with four concentric rectangles: the margin rectangle, the border rectangle, the padding rectangle, and the content rectangle. The box model describes this in further detail.</p> <a name="box-model"></a><a name="the-box-model"></a> <h2 id="the-box-model">The Box Model</h2> <p>The four concentric rectangles appear conceptually as below:</p> <p class="centerAlign"><img src="images/stylesheet-boxmodel.png" alt="" /></p><ul> <li>The margin falls outside the border.</li> <li>The border is drawn between the margin and the padding.</li> <li>The padding falls inside the border, between the border and the actual contents.</li> <li>The content is what is left from the original widget or subcontrol once we have removed the margin, the border, and the padding.</li> </ul> <p>The <a href="stylesheet-reference.html#margin-prop">margin</a>, <a href="stylesheet-reference.html#border-width-prop">border-width</a>, and <a href="stylesheet-reference.html#padding-prop">padding</a> properties all default to zero. In that case, all four rectangles (<code>margin</code>, <code>border</code>, <code>padding</code>, and <code>content</code>) coincide exactly.</p> <p>You can specify a background for the widget using the <a href="stylesheet-reference.html#background-image-prop">background-image</a> property. By default, the background-image is drawn only for the area inside the border. This can be changed using the <a href="stylesheet-reference.html#background-clip-prop">background-clip</a> property. You can use <a href="stylesheet-reference.html#background-repeat-prop">background-repeat</a> and <a href="stylesheet-reference.html#background-origin-prop">background-origin</a> to control the repetition and origin of the background image.</p> <p>A background-image does not scale with the size of the widget. To provide a "skin" or background that scales along with the widget size, one must use <a href="stylesheet-reference.html#border-image-prop">border-image</a>. Since the border-image property provides an alternate background, it is not required to specify a background-image when border-image is specified. In the case, when both of them are specified, the border-image draws over the background-image.</p> <p>In addition, the <a href="stylesheet-reference.html#image-prop">image</a> property may be used to draw an image over the border-image. The image specified does not tile or stretch and when its size does not match the size of the widget, its alignment is specified using the <a href="stylesheet-reference.html#image-position-prop">image-position</a> property. Unlike background-image and border-image, one may specify a SVG in the image property, in which case the image is scaled automatically according to the widget size.</p> <p>The steps to render a rule are as follows:</p> <ul> <li>Set clip for entire rendering operation (border-radius)</li> <li>Draw the background (background-image)</li> <li>Draw the border (border-image, border)</li> <li>Draw overlay image (image)</li> </ul> <a name="sub-controls"></a><a name="sub-controls"></a> <h2 id="sub-controls">Sub-controls</h2> <p>A widget is considered as a hierarchy (tree) of subcontrols drawn on top of each other. For example, the <a href="qcombobox.html">QComboBox</a> draws the drop-down sub-control followed by the down-arrow sub-control. A <a href="qcombobox.html">QComboBox</a> is thus rendered as follows:</p> <ul> <li>Render the <a href="qcombobox.html">QComboBox</a> { } rule</li> <li>Render the QComboBox::drop-down { } rule</li> <li>Render the QComboBox::down-arrow { } rule</li> </ul> <p>Sub-controls share a parent-child relationship. In the case of <a href="qcombobox.html">QComboBox</a>, the parent of down-arrow is the drop-down and the parent of drop-down is the widget itself. Sub-controls are positioned within their parent using the <a href="stylesheet-reference.html#subcontrol-position-prop">subcontrol-position</a> and <a href="stylesheet-reference.html#subcontrol-origin-prop">subcontrol-origin</a> properties.</p> <p>Once positioned, sub-controls can be styled using the <a href="stylesheet-customizing.html#box-model">box model</a>.</p> <p><b>Note: </b>With complex widgets such as <a href="qcombobox.html">QComboBox</a> and <a href="qscrollbar.html">QScrollBar</a>, if one property or sub-control is customized, <b>all</b> the other properties or sub-controls must be customized as well.</p></div> <!-- @@@stylesheet-customizing.html --> <p class="naviNextPrevious footerNavi"> <a class="prevPage" href="stylesheet-designer.html">Qt Designer Integration</a> <span class="naviSeparator"> ◦ </span> <a class="nextPage" href="stylesheet-reference.html">Qt Style Sheets Reference</a> </p> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2019 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.<br/> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br/> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners. </p> </div> </body> </html>