#include <QCoreApplication>
#include <QImage>
#include <QPainter>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QImage img(200, 200, QImage::Format_ARGB32_Premultiplied);
    img.fill(Qt::transparent);
    QPainter p(&img);
    p.setPen(QPen(Qt::yellow, 3));
    p.drawLine(50, 50, 100, 50);
    p.end();
    img.save("example.png");

    return 0;
}