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<td >Qt 5.12</td><td ><a href="qtdatavisualization-index.html">Qt Data Visualization</a></td><td >Qt Quick 2 Scatter Example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right"><a href="qtdatavisualization-index.html">Qt Data Visualization | Commercial or GPLv3</a></td>
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<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#running-the-example">Running the Example</a></li>
<li class="level1"><a href="#application-basics">Application Basics</a></li>
<li class="level1"><a href="#setting-up-the-graph">Setting up the Graph</a></li>
<li class="level1"><a href="#adding-data-to-the-graph">Adding Data to the Graph</a></li>
<li class="level1"><a href="#example-contents">Example Contents</a></li>
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<h1 class="title">Qt Quick 2 Scatter Example</h1>
<span class="subtitle"></span>
<!-- $$$qmlscatter-brief -->
<p>Using <a href="qml-qtdatavisualization-scatter3d.html">Scatter3D</a> in a QML application.</p>
<!-- @@@qmlscatter -->
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<div class="descr"> <a name="details"></a>
<p>The Qt Quick 2 scatter example shows how to make a simple scatter graph visualization using <a href="qml-qtdatavisualization-scatter3d.html">Scatter3D</a> and Qt Quick 2.</p>
<p>For instructions about how to interact with the graph, see <a href="qtdatavisualization-interacting-with-data.html">this page</a>.</p>
<p>For instructions how to create a new Qt Quick 2 application of your own, see Qt Creator help.</p>
<p class="centerAlign"><img src="images/qmlscatter-example.png" alt="" /></p><a name="running-the-example"></a>
<h2 id="running-the-example">Running the Example</h2>
<p>To run the example from Qt Creator, open the <b>Welcome</b> mode and select the example from <b>Examples</b>. For more information, visit Building and Running an Example.</p>
<a name="application-basics"></a>
<h2 id="application-basics">Application Basics</h2>
<p>Before diving into the QML code, let's take a look at the application <code>main.cpp</code>.</p>
<p>This application implements a 'Quit' button in the UI, so we want to connect the QQmlEngine::quit() signal to our application's QWindow::close() slot:</p>
<pre class="cpp">
<span class="type">QObject</span><span class="operator">::</span>connect(viewer<span class="operator">.</span>engine()<span class="operator">,</span> <span class="operator">&</span><span class="type">QQmlEngine</span><span class="operator">::</span>quit<span class="operator">,</span> <span class="operator">&</span>viewer<span class="operator">,</span> <span class="operator">&</span><span class="type">QWindow</span><span class="operator">::</span>close);
</pre>
<p>To make deployment little simpler, we gather all of the application's <code>.qml</code> files to a resource file (<code>qmlscatter.qrc</code>):</p>
<pre class="cpp">
<span class="operator"><</span>RCC<span class="operator">></span>
<span class="operator"><</span>qresource prefix<span class="operator">=</span><span class="string">"/"</span><span class="operator">></span>
<span class="operator"><</span>file<span class="operator">></span>qml<span class="operator">/</span>qmlscatter<span class="operator">/</span>Data<span class="operator">.</span>qml<span class="operator"><</span><span class="operator">/</span>file<span class="operator">></span>
<span class="operator"><</span>file<span class="operator">></span>qml<span class="operator">/</span>qmlscatter<span class="operator">/</span>main<span class="operator">.</span>qml<span class="operator"><</span><span class="operator">/</span>file<span class="operator">></span>
<span class="operator"><</span>file<span class="operator">></span>qml<span class="operator">/</span>qmlscatter<span class="operator">/</span>NewButton<span class="operator">.</span>qml<span class="operator"><</span><span class="operator">/</span>file<span class="operator">></span>
<span class="operator"><</span><span class="operator">/</span>qresource<span class="operator">></span>
<span class="operator"><</span><span class="operator">/</span>RCC<span class="operator">></span>
</pre>
<p>This also requires us to set the <code>main.qml</code> to be read from the resource (<code>qrc:</code>):</p>
<pre class="cpp">
viewer<span class="operator">.</span>setSource(<span class="type">QUrl</span>(<span class="string">"qrc:/qml/qmlscatter/main.qml"</span>));
</pre>
<p>Lastly, we want the application to run in a maximized window:</p>
<pre class="cpp">
viewer<span class="operator">.</span>showMaximized();
</pre>
<a name="setting-up-the-graph"></a>
<h2 id="setting-up-the-graph">Setting up the Graph</h2>
<p>First we'll import all the QML modules we need:</p>
<pre class="qml">
import QtQuick 2.1
import QtQuick.Layouts 1.0
import QtDataVisualization 1.0
import "."
</pre>
<p>The last <code>import</code> just imports all the qml files in the same directory as our <code>main.qml</code>, because that's where <code>NewButton.qml</code> and <code>Data.qml</code> are.</p>
<p>Then we create our main <code>Rectangle</code> and call it <code>mainView</code>:</p>
<pre class="qml">
Rectangle {
id: mainView
</pre>
<p>Then we'll add another <code>Item</code> inside the main <code>Rectangle</code>, and call it <code>dataView</code>. This will be the item to hold the <a href="qml-qtdatavisualization-scatter3d.html">Scatter3D</a> graph. We'll anchor it to the parent bottom:</p>
<pre class="qml">
Item {
id: dataView
anchors.bottom: parent.bottom
</pre>
<p>Next we're ready to add the <a href="qml-qtdatavisualization-scatter3d.html">Scatter3D</a> graph itself. We'll add it inside the <code>dataView</code> and name it <code>scatterGraph</code>. Let's make it fill the <code>dataView</code>:</p>
<pre class="qml">
Scatter3D {
id: scatterGraph
width: dataView.width
height: dataView.height
</pre>
<p>Now the graph is ready for use, but has no data. It also has the default axes and visual properties.</p>
<p>Let's modify some visual properties first by adding the following inside <code>scatterGraph</code>:</p>
<pre class="qml">
theme: themeIsabelle
shadowQuality: AbstractGraph3D.ShadowQualitySoftLow
</pre>
<p>We added a customized theme and changed the shadow quality. We're happy with the other visual properties, so we won't change them.</p>
<p>The custom theme is based on a predefined theme, but we change the font in it:</p>
<pre class="qml">
Theme3D {
id: themeIsabelle
type: Theme3D.ThemeIsabelle
font.family: "Lucida Handwriting"
font.pointSize: 40
}
</pre>
<p>Then it's time to start feeding the graph some data.</p>
<a name="adding-data-to-the-graph"></a>
<h2 id="adding-data-to-the-graph">Adding Data to the Graph</h2>
<p>Let's create a <code>Data</code> item inside the <code>mainView</code> and name it <code>seriesData</code>:</p>
<pre class="qml">
Data {
id: seriesData
}
</pre>
<p>The <code>seriesData</code> item contains the data models for all three series we use in this example.</p>
<p>This is the component that holds our data in <code>Data.qml</code>. It has an <code>Item</code> as the main component.</p>
<p>In the main component we'll add the data itself in a <code>ListModel</code> and name it <code>dataModel</code>:</p>
<pre class="qml">
ListModel {
id: dataModel
ListElement{ xPos: -10.0; yPos: 5.0; zPos: -5.0 }
...
</pre>
<p>We'll add two more of these for the other two series, and name them <code>dataModelTwo</code> and <code>dataModelThree</code>.</p>
<p>Then we need to expose the data models to be usable from <code>main.qml</code>. We do this by defining them as aliases in the main data component:</p>
<pre class="qml">
property alias model: dataModel
property alias modelTwo: dataModelTwo
property alias modelThree: dataModelThree
</pre>
<p>Now we can use the data from <code>Data.qml</code> with <code>scatterGraph</code> in <code>main.qml</code>. First we'll add a <a href="qml-qtdatavisualization-scatter3dseries.html">Scatter3DSeries</a> and call it <code>scatterSeries</code>:</p>
<pre class="qml">
Scatter3DSeries {
id: scatterSeries
</pre>
<p>Then we'll set up selection label format for the series:</p>
<pre class="qml">
itemLabelFormat: "Series 1: X:@xLabel Y:@yLabel Z:@zLabel"
</pre>
<p>And finally the data for series one in a <a href="qml-qtdatavisualization-itemmodelscatterdataproxy.html">ItemModelScatterDataProxy</a>. We set the data itself as <code>itemModel</code> for the proxy:</p>
<pre class="qml">
ItemModelScatterDataProxy {
itemModel: seriesData.model
xPosRole: "xPos"
yPosRole: "yPos"
zPosRole: "zPos"
}
</pre>
<p>We'll add the other two series in the same way, but modify some series-specific details a bit:</p>
<pre class="qml">
Scatter3DSeries {
id: scatterSeriesTwo
itemLabelFormat: "Series 2: X:@xLabel Y:@yLabel Z:@zLabel"
itemSize: 0.1
mesh: Abstract3DSeries.MeshCube
...
</pre>
<p>Then we'll modify the properties of the default axes in <code>scatterGraph</code> a bit:</p>
<pre class="qml">
axisX.segmentCount: 3
axisX.subSegmentCount: 2
axisX.labelFormat: "%.2f"
axisZ.segmentCount: 2
axisZ.subSegmentCount: 2
axisZ.labelFormat: "%.2f"
axisY.segmentCount: 2
axisY.subSegmentCount: 2
axisY.labelFormat: "%.2f"
</pre>
<p>After that we'll just add a few buttons to the <code>mainView</code> to control the graph. We'll only show one as an example:</p>
<pre class="qml">
NewButton {
id: shadowToggle
Layout.fillHeight: true
Layout.fillWidth: true
text: scatterGraph.shadowsSupported ? "Hide Shadows" : "Shadows not supported"
enabled: scatterGraph.shadowsSupported
onClicked: {
if (scatterGraph.shadowQuality === AbstractGraph3D.ShadowQualityNone) {
scatterGraph.shadowQuality = AbstractGraph3D.ShadowQualitySoftLow;
text = "Hide Shadows";
} else {
scatterGraph.shadowQuality = AbstractGraph3D.ShadowQualityNone;
text = "Show Shadows";
}
}
}
</pre>
<p>Then we'll modify <code>dataView</code> to make room for the buttons at the top:</p>
<pre class="qml">
Item {
id: dataView
anchors.bottom: parent.bottom
width: parent.width
height: parent.height - buttonLayout.height
...
</pre>
<p>And we're done!</p>
<a name="example-contents"></a>
<h2 id="example-contents">Example Contents</h2>
<p>Files:</p>
<ul>
<li><a href="qtdatavisualization-qmlscatter-main-cpp.html">qmlscatter/main.cpp</a></li>
<li><a href="qtdatavisualization-qmlscatter-qml-qmlscatter-data-qml.html">qmlscatter/qml/qmlscatter/Data.qml</a></li>
<li><a href="qtdatavisualization-qmlscatter-qml-qmlscatter-newbutton-qml.html">qmlscatter/qml/qmlscatter/NewButton.qml</a></li>
<li><a href="qtdatavisualization-qmlscatter-qml-qmlscatter-main-qml.html">qmlscatter/qml/qmlscatter/main.qml</a></li>
<li><a href="qtdatavisualization-qmlscatter-qmlscatter-pro.html">qmlscatter/qmlscatter.pro</a></li>
<li><a href="qtdatavisualization-qmlscatter-qmlscatter-qrc.html">qmlscatter/qmlscatter.qrc</a></li>
</ul>
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