#357 QwtPlotOpenGLCanvas devicePixelRatio Qt6

[peppermg]

When using QwtPlotOpenGLCanvas if you have multiple screens with different resolutions and drag a plot from one screen to another the canvas will become offset. This behavior can be seen in the refreshtest example (screenshots attached). This issue was discovered after porting a project from Qt5.15.2 to Qt6.4, issue does not appear to happen in Qt5.

changing

const qreal pixelRatio = QwtPainter::devicePixelRatio( NULL );

to

const qreal pixelRatio = QwtPainter::devicePixelRatio( this );

in QwtPlotOpenGLCanvas::paintGL() appears to fix the issue

[Uwe Rathmann]

Of course you are right. Fixed in all branches >= 6.2