QwtPlotSpectroCurve: how to use triangles, squares, etc. instead of dot?

[Alekon]

Hi,

this is my first message in this forum, and firstly - Uwe, great work (Qwt), many thanks!

And now the question - it is in the thread title. For instance, I want two QwtPlotSpectroCurve on a plot: first with dots and second with triangles to distinguish them.

Thanks

[Cah]

Maybe subclass QwtPlotSpectroCurve and overload drawDots()...

[Alekon]

Thanks for your interest.

drawPoints() can be used. After some preparation work, it calls QwtPainter::drawPoint() that may be replaced with something that draws what I need (triangle, rect, etc.).

[Cah]

After some preparation work, it calls QwtPainter::drawPoint() that may be replaced with something that draws what I need (triangle, rect, etc.).

QwtPainter::drawPoint() is a wrapper for QPainter::drawPoint().
QPainter::drawPoint() is non virtual.

[Uwe]

QwtPlotSpectroCurve is a plot item for 3d points where the z value is mapped to color. As this is obviously not what you need consider to derive from its base class ( = displaying 3d points somehow ) instead.

In case of deriving from QwtPlotSpectroCurve you would have to overload QwtPlotSpectroCurve::drawDots() accepting that parts of the class API are left pointless.

Uwe