QwtPlotZoomer Rectangle Color

Question

does anyone know how to change the box and text color of the QwtPlotZoomer object in C++? My plot canvas background is black and the box that is drawn when dragging the mouse is also black, making it difficult to see the zoom selection.

Thanks!

Answer 1

Use setRubberBandPen() to pass the QPen() that has the color of the edge of the rectangle.

Example:

#include <QApplication>
#include <QMainWindow>

#include <qwt_plot.h>
#include <qwt_plot_curve.h>
#include <qwt_plot_zoomer.h>


int main( int argc, char **argv )
{
    QApplication a( argc, argv );
    a.setStyleSheet("QwtPlotCanvas { background: black; } ");

    QwtPlot * plot = new QwtPlot();
    plot->setAxisAutoScale(QwtPlot::xBottom);
    plot->setAxisAutoScale(QwtPlot::yLeft);

    QwtPlotZoomer *zoomer;
    zoomer = new QwtPlotZoomer( QwtPlot::xBottom, QwtPlot::yLeft, plot->canvas() );
    zoomer->setRubberBandPen(QPen(Qt::white));

    // create data
    std::vector<double> x(100);
    std::vector<double> y1(x.size());

    for (size_t i = 0; i< x.size(); ++i) { x[i] = int(i)-50; }
    for (size_t i = 0; i< y1.size(); ++i) {
        y1[i] = i*i;
    }

    // first curve
    QwtPlotCurve *curve = new QwtPlotCurve();
    curve->setPen(Qt::white);
    curve->setRawSamples(&x[0], &y1[0], x.size());
    curve->attach( plot );
    plot->replot();

    QMainWindow window;
    window.setCentralWidget(plot);
    window.resize(800, 600);
    window.show();

    return a.exec();
}