RE: [Discuss-gnuradio] gr_qtgui, SWIG. QT Signals and such

[Mike Cornelius]

> -----Original Message-----
> From: Alexandru Csete [mailto:address@hidden
> Sent: Wednesday, 5 January 2011 12:47 AM
> To: Mike Cornelius
> Cc: Tom Rondeau; address@hidden
> Subject: Re: [Discuss-gnuradio] gr_qtgui, SWIG. QT Signals and such
> 
> Greetings,
> 
> Few months ago I started experimenting with using Qt and the gr-qtgui
> component and I found it to be much easier to work with that wxPython.
> 

Hi Alex,

Credit where credit is due, It was actually your gqrx project that got me
started on this :)
I noticed in your screenshots that you had changed the plot colours and I
thought 'That looks nicer, I wonder how he did that ?', of course once I
started playing around with the qtgui code I figured there were a few more
things that I could fiddle with.

> I found the additional controls to be useful when they are needed but
> they take up quite a lot pf vertical space. In the present
> configuration they consume about 1/3 of the vertical space and this
> doesn't leave much room for application widgets on e.g. laptop screens
> which are usually limited to less than 800 pixels.
> 

Furthermore the current control isn't ideally suited to having more than 1
plot on an UI or to small plot areas.
I don't want to neglect the existing control though as having to put
together a custom layout is probably more trouble than it's worth in a lot
of cases.
I think adding interfaces to the existing control for things like the
markers, grids, colours and the form controls would be useful too.



> On Tue, Jan 4, 2011 at 10:00 AM, Mike Cornelius <address@hidden>
> wrote:
> > On Tue, Jan 4, 2011 at 2:42 AM, Tom Rondeau <address@hidden>
> wrote:
> >> On Mon, Jan 3, 2011 at 2:53 AM, Mike Cornelius <address@hidden>
> wrote:
> >>> - Added a center frequency marker and interface
> >>> - Changed zoomer to use drag select rather than click select
> >>
> >> I'm not sure what you mean by this. Probably GUI lingo that I'm not
> >> familiar with. Could you explain?
> >
> > The CF marker is a vertical line in the centre of the spectrum plot
> window,
> > it's a handy visual tuning aid (like Marker->CF on an a spectrum
> analyser).
> 
> May I suggest to make it a generic marker that can be placed anywhere
> not just at the center. Also, enabling the major grids of the QwtPlot
> widget will add a vertical line at 0.
> 

Absolutely.

> > Presently the zoom function in gr_qtgui works as 'click - drag -
> click' I
> > changed it to 'button down - drag - button up'
> 
> To me 'button down - drag - button up' already zooms on all gr-qtgui
> plots. 'click - drag - click' does nothing...
> I wonder if this is some desktop specific setting? I use Gnome desktop.
> 
> Alex

Hmm interesting, I use Gnome too (Ubuntu 10.4)

The change was trivial, in FrequencyDisplayPlot.cc I changed:-

_zoomer->setSelectionFlags(QwtPicker::RectSelection |
QwtPicker::ClickSelection);
to
_zoomer->setSelectionFlags(QwtPicker::RectSelection |
QwtPicker::DragSelection);

Mike