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I am writing a simple program to display raster data using qgis api C++.
When I open raster data that has different coordinate systems, the on-the-fly feature does not work on my mapCanvas.
Can someone help me?

OpenGisData::OpenGisData(QWidget *parent)
: QMainWindow(parent)
{
    setupUi(this);
    QWidget* centralWidget = OpenGisDataClass::centralWidget;
    mMapCanvas = new QgsMapCanvas(centralWidget);
    QGridLayout* gridLayout = new QGridLayout;
    gridLayout->addWidget(mMapCanvas);
    centralWidget->setLayout(gridLayout);
    connect(actionOpen, &QAction::triggered, this, &OpenGisData::open);
}
void OpenGisData::open()
{
    QString fileName = QFileDialog::getOpenFileName(this, "Open data", "D:\\Test");
    if (!fileName.isEmpty())
    {
        QgsRasterLayer* rasterLayer = new QgsRasterLayer(fileName);
        if (rasterLayer && rasterLayer->isValid())
        {
            QList<QgsMapLayer*> layers = mMapCanvas->layers();
            layers.append(rasterLayer);

            mMapCanvas->setLayers(layers);
            mMapCanvas->zoomToFullExtent();
        }
    }
}
0

I solved my problem by adding the following code:

connect(QgsProject::instance(), &QgsProject::crsChanged, [=] {
    QgsCoordinateReferenceSystem crs = QgsProject::instance()->crs();
    mMapCanvas->setDestinationCrs(crs);
});

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