@mrjj thank you a lot!
The original source-code of this old post was not working and it have a lot of warnings...
So I modified to get a complete and zero errors/warnings modern Qt example.
Here is the full source-code:
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtCharts/QChartView>
#include <QtCharts/QLineSeries>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
//Build a series to add to the chart
QtCharts::QLineSeries *series = new QtCharts::QLineSeries();
*series << QPointF(11, 1) << QPointF(13, 3) << QPointF(17, 6) << QPointF(18, 3) << QPointF(20, 2);
//Create a chart object and format
QtCharts::QChart *chart = new QtCharts::QChart();
chart->legend()->hide();
chart->addSeries(series);
chart->createDefaultAxes();
chart->axes(Qt::Vertical).first()->setGridLineVisible(false);
chart->axes(Qt::Horizontal).first()->setGridLineVisible(false);
//Bring in the background image from Qt resource
QImage skyplot(":/SkyPlot.jpg");
if (skyplot.isNull()) { return; }
// ===== CHART VIEWER ===== //
// Create a Chart Viewer:
QtCharts::QChartView* chartView = new QtCharts::QChartView();
//Add the chart to the view widget
chartView->setChart(chart);
chartView->setRenderHint(QPainter::Antialiasing, true);
//Note: Since we added the chart to the view we can now
//scale and translate the image appropriately. The chart
//has an appropriate size.
//Grab the size of the plot and view areas
int width = static_cast<int>(chart->plotArea().width());
int height = static_cast<int>(chart->plotArea().height());
int ViewW = static_cast<int>(chartView->width());
int ViewH = static_cast<int>(chartView->height());
//scale the image to fit plot area
skyplot = skyplot.scaled(QSize(width, height));
//We have to translate the image because setPlotAreaBackGround
//starts the image in the top left corner of the view not the
//plot area. So, to offset we will make a new image the size of
//view and offset our image within that image with white
QImage translated(ViewW, ViewH, QImage::Format_ARGB32);
translated.fill(Qt::white);
QPainter painter(&translated);
QPointF TopLeft = chart->plotArea().topLeft();
painter.drawImage(TopLeft, skyplot);
//Display image in background
chart->setPlotAreaBackgroundBrush(translated);
chart->setPlotAreaBackgroundVisible(true);
// Add widget to GUI:
ui->gridLayout->addWidget(chartView);
}
3 key points:
In the UI file, you have to add a gridLayout to the MainWindow window.
Add the charts in your *.pro file Qt += charts
The background image must be in a Qt resource file
The final result is this chart + a backgroud image:
[image: d474cfe6-3659-4baf-8935-59ca8075ba3e.png]
