Re: [Usability] Zoom Controls

[Bastien Nocera <hadess hadess net>]

On Wed, 2010-04-21 at 21:46 +0100, Allan Day wrote:
> > Coincidentally, yesterday I was trying to munge Federico's ideas into 
> > the UI Pattern Template I've been working on-- primarily to continue to 
> > exercise the template rather than suggest a concrete design for zoom 
> > controls, so I'm not saying the pattern I came up with is particularly 
> > valid-- I do still show the zoom in terms of percentage, for example. 
> > But just for the record, here's where I got to (some sections incomplete):
> > <http://live.gnome.org/UsabilityProject/HIG/ImageZoomExamplePattern>
> 
> There's some really good stuff on this page.
> 
> <snip>
> > I mentioned on IRC yesterday that I think there are actually probably a 
> > couple of different use cases here-- the one where the bounds of the 
> > allowable zooming are practically infinite (e.g. a vector graphics 
> > editor), and one where you could sensibly define them for most use cases 
> </snip>
> 
> Yes - it'll be useful to distinguish those in the pattern and to suggest
> different controls accordingly.
> 
> > In the 'defined bounds' case, I think providing a slider can still be 
> > useful, and I do quite like the way OpenOffice's zoom slider works, with 
> > a couple of 'magnetic' points along the way for 'fit width' and 'fit to 
> > window'.  Where the bounds are large, having the slider behave in some 
> > sort of exponential fashion might also be an option, although that would 
> > probably need some tinkering to make it feel right and work well.
> 
> I'm still not entirely sure about the practical benefits of sliders, but
> they may have non-practical advantages: they can look nice, and I
> suspect people like them as something that they can play with. They can
> be a nice change from the usual kinds of widgets you encounter.

Two things I wanted to mention.

Totem also has a zoom feature, though it doesn't have toolbar items for
it. We use menus and the default zoom level is "1:1", we say "Zoom
reset" for the "normal zoom" button.

The second thing is that Mitch did some work on the GtkScaleButton,
which is currently only used for volume buttons, to allow them be
horizontal. The goal was to be able to have unintrusive/small buttons
that would allow you to select the zoom level.

With very little work, somebody could provide a GtkZoomButton to the
same effect for use in toolbar where the space might be more
constrained.

For image management application, when the zoom is an essential feature,
another more verbose widget could be necessary.

Cheers