@J-Hilk Ok that's enough I think. One more question what will happen to scrolleft(). If I keep on incrementing these, will there be any increase in runtime memory or processor load?

Hello! If I understood correctly, and you want to use the same chart view to represent the data in different forms like bars or line, I don't see any reason why not. If you take a look at https://doc.qt.io/qt-5/qtcharts-lineandbar-example.html, you can find an example of showing both a bar and line charts in the same chart, at the same time. From there, you can modify to show just one at a time, so in your case switching between the series when the menu action is triggered.

@psryan it's a member of the Context2d QML type. See the docs for that and Canvas.

@suslucoder If your files all have the same structure (separator, data etc.), yes, you should actually.

@suslucoder said in Creating a chart with multiple datas: Should i delete them? No. Why would you?

@suslucoder What exactly can't you understand? In the documentation @SGaist posted there is even an example with signal/slot with parameter...

In the loop you use to read your file.

@JonB Hmmmm, i got. actually what i want to do is scrolling my chart. I have about 20 point, and i cant see all of them on the secreen. It shows just up to the size of the axis, and the others cant seen on the secreen. There are too many datas on the right but we cannot see.

@Pl45m4 Thank you

@JonB Thank you, it works

@suslucoder As the error message tells you addSeries takes a QAbstractSeries, not a string list as parameter. You have to pass it one of the QAreaSeries, QBoxPlotSeries, QCandlestickSeries, QPieSeries, and QXYSeries. You also should tell us what data your file actually contains? If it contains x/y values then you first have to convert the data to numbers and create a QXYSeries instance and fill it with that data (https://doc.qt.io/qt-5/qxyseries.html#append).

@SGaist Good catch. yes its x,y. It was more about num being undeclared at that point in time :) Changed as not to confuse future readers.

When using line series, we've had severe performance problems. We end up with thousands of series to handle all of the gaps and have to create parallel scatter series because we want icons for each point that aren't part of the standard icon set. We pay a huge cost both constructing and destructing the series. Seems like it may be refreshing on each add series, but even removeAllSeries is slow. Have tried many things to suspend the painting, but with no timing effect. Any ideas on how to have many gaps without destroying performance?

Yes, in another project. QGraphicsView lays a top of QAbstaractScrollArea, so scroll bars appears there out of a box. But it requires a few lines of code to add scrolling by drag a scene. This time I needed QML way.

@KRHC hi and welcome to devnet, You need QApplication if you use anything that relies on the widgets module. Otherwise, there's no need for it and you would just bloat your deployment for no good reason.

@vishnu The control will go ahead if and only if both properties are initialized. Its a normal & operation.

Hi @Hedge, You have following ways to do it: Defining QML Types from C++ In short create a QObject derived class and register it using qmlRegisterType so that it is available in QML. Exposing Attributes of C++ Types to QML Create a QObject derived class , add some public slots or Q_INVOKABLE functions and make these available by setting that class as a contextProperty. In both the cases it will be good idea to provide some properties defined as Q_PROPERTY with their respective signals so that QML gets notified on changes in the values of these properties from C++.

Hi, QtCharts is a commercial package, you should rather contact the Qt Company through your Qt Account Support Center link.

BarSeries { id: currentPlot axisX: BarCategoryAxis { id: categoryAxis labelsFont:Qt.font({pointSize: 6}) Qt.font function accept an javascript object with all keys relevant to font. The most commonly used properties are: string font.family bool font.bold bool font.italic bool font.underline real font.pointSize int font.pixelSize

vertexData() returns only the data in ram and not the real VBO which is stored in GPU-ram. As soon as you mark it as dirty it gets completely copied into GPU. Meanwhile I have implemented a direct opengl-way where I create the VBO myself. Thanks anyway! cu

Hi and welcome to devnet, The best way to have information for 1 and 2 is to contact the Qt Company directly. These two modules are available to the commercial customers but you can try them with the trial package. AFAIK, Qwt only provides widgets I don't know that one Hope it helps