Re: Qt graphics zooming

[John W. Eaton]

On 03/03/2015 02:01 PM, Ben Abbott wrote:
> > On Mar 3, 2015, at 1:55 PM, John W. Eaton <address@hidden> wrote:
> >
> > On 03/03/2015 01:28 PM, Rik wrote:
> >
> > > This works well when using single mouse clicks.  I would add the same
> > > code to the canvasWheelEvent so that mouse wheel zoom is also based on
> > > the current location.
> > >
> > > -- Canvas.cc:795 --
> > > // FIXME: should we zoom about point for 2D plots?
> > >
> > > ap.zoom (mode, factor);
> > > -- End Code --
> > >
> > > It looks like that may have been intended.
> >
> > I'm not sure that's how Matlab works.  Maybe someone else can verify?
> >
> > I don't really care one way or the other, but if we diverge from what Matlab 
> > does, I expect we'll get a bug report about it...
> >
> > jwe
>
> I happy to try on Matlab, but I'm not following what needs to be done.
>
> To illustrate where I'm lost .... If the mouse clicking the a zoom button why 
> would the zoom be based upon the location of the mouse?
>
> If a hot key is being used to zoom, I don't think Matlab supports that.

If you create a plot, then select the zoom mode from the toolbar, then 
click in the plot window, does the zooming happen around the location of 
the click, or does it happen around the center of the plot axes?

Similarly, if you are in zoom mode and zoom with the mouse wheel, does 
it zoom around the location of the cursor, or does it zoom around the 
center of the plot axes?

jwe