Re: ScrollZoomer

[Houssem B. <hou...@gm...>]

Hi Uwe,

  Thanks a lot for your answer.
I'll let you know my advance on this.

Regards,
Houssem

On Dec 18, 2007 10:33 AM, Uwe Rathmann <Uwe...@ti...> wrote:

> On Monday 17 December 2007 15:02, Houssem BDIOUI wrote:
>
> >   Is it possible to adapt the ScrollZoomer of the real-time example
> > in order to scroll around a zoomed plot having 2 y-axes (right and
> left)?
>
> Of course it is possible somehow, but I'm not sure if it is easy enough,
> that
> you like it. I would try to overload QwtPlotZoomer::rescale().
>
> Something like this:
>
> virtual void YourZoomer: public ScrollZoomer
> {
> protected:
>    virtual void rescale()
>    {
>         ScrollZoomer::rescale();
>
>         // now calculate the opposite y-axis
>         // from the ratio of the y-axis and adjust it
>         // using plot()->setAxisScale()
>         ...
>    }
> }
>
> Another idea is to use two zoomers ( like in the bode plot ), but only one
> of
> the is a ScrollZoomer. The other zoomer needs to be connected to the
> valueChanged signal of the vertical scrollbar.
>
> > A second question: why isn't this scrolling capability is'nt integrated
> in
> > the Qwt library itself?
>
> I'm not happy with this class, because it has no concept for plots with
> more
> than one x/y axis. But it seems to be useful for many applications, so I
> already though about an integration in 5.1.
>
> Uwe
>
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