Re: panning in scrolledWindow/viewport

[Kees Kling <ckling upcmail nl>]

On 10/09/2012 09:50 AM, Ian Martin wrote:
> On 08/10/12 00:04, Kees Kling wrote:
> > Hi all,
> >
> > I'm working on a project to display images. These images are loaded 
> > in a Gtk::DrawingArea. Most of the time these images are too big, so 
> > I want to pan these images with the mouse. I tried a viewport and a 
> > scrolled window to pack this drawingarea and do the panning in a 
> > motion_notify_event by changing the values of the gtk::adjustment 
> > object. It is working, but terrible slow. It must be possible to do 
> > this faster, because when I load these images in the "Gimp" I can do 
> > this type of panning in a rather smooth way.
> >
> > So my questions are
> >
> > Must I use a viewport or scrolledwindow object?
> >
> > Is it correct to pan by changing the adjustment objects or is there a 
> > better ( faster ) way?
> >
> > Thanks
> >
> > Kees Kling
> > _______________________________________________
> > gtkmm-list mailing list
> > gtkmm-list gnome org
> > https://mail.gnome.org/mailman/listinfo/gtkmm-list
> Hi Kees,
> Did you look at using a Gtk::Layout?  It packs the Gtk::DrawingArea 
> into a viewport for you, and seemed to work better for me.
>
> Ian.

Hi Ian,

thanks for your advise. Meanwhile I was still woring on the project and 
found out that the scrolling wasn't the real botlleneck, but the way I 
was rendering the image. I changed that and had a lot of speed 
improvement, but I will try your method

Thanks

Kees