Re: serious data plot bug

[Uwe R. <Uwe...@ti...>]

On Monday 28 January 2008 21:24, Igor Mironchick wrote:

> I test my app with and without using QwtPlotCurve::ClipPolygons. And
> there is one question. Why by default there are no any optimisation with
> plotting curves? When it seems by the naked eye that plotting with
> QwtPlotCurve::ClipPolygons are much faster than without!!!

Its only faster because of the special characteristics of your data and the 
bad way Qt4 deals with it. In most situations ( using a default pen or no 
points very far outside ) polygon clipping is slower, because the calculation 
itsself takes time without improving anything. And I want to have the default 
Qwt settings suitable for the average use case.

By the way: the problem might be worse on Windows, but should be there on all 
platforms, because Qt renders all of these huge lines without checking if 
this makes sense at all.

Uwe