Re: [Usability] How much intendation should be used for grouped widgets?

[merchan baton phys lsu edu]

On Sun, Jun 15, 2003 at 02:08:07PM +0200, Christian Neumair wrote:
> I originally sent this mail to the hig list, but as I'd like to reach a
> bigger developer/subscriber base, this mail has been resent to the
> usability list.
> 
> Our current HIGifying situation is more than unsatisfying when it comes
> to the category intendation. Currently three different values are used:
> 12 px, 18 px as well as 4 spaces ("    ").

Do not use 4 spaces; that's a bad hack that should never have been
suggested by the HIG.

Spacing recommendation throughout the HIG neglects the developers.
Programming with Gtk+, when you see the HIG state 12px should be used,
you assume that an integer argument to some function will be 12. This is,
sadly, not the case. The HIG requires you to look at what is rendered,
adjust, look again, adjust, ad nauseam, until you can count 12px between
two points. Nevermind that another theme may change that.

Incredible? See http://bugzilla.gnome.org/show_bug.cgi?id=95773


> While the HIG states that you ought to "(i)ndent group members 12 pixels
> to denote hierarchy and association." [1], another image on the same
> page [2] obviously uses 18 px for that. In my opinion this shows that
> the HIG authors themselves prefer 18 px over 12 px.

This particular problem has been mentioned in the bug reports pertaining
to indented groups.

  http://bugzilla.gnome.org/show_bug.cgi?id=96374
  http://bugzilla.gnome.org/show_bug.cgi?id=98384


> In my AbiWord HIGifying efforts I used 18 px for that intendation and I
> must say that it looks way better than 12 px. Third candidate it the
> "    " intendation, but I don't think it's a good idea to make the
> indenation dependant on the currently used font width.

It depend on font width, but not that way. Ideally, it would be a function
of em width so that there is a obvious but not obnoxious indentation; too
much for a small font looks askew, too little for a large font is almost
imperceptible. Gtk+ does not (yet?) make em-based sizes easy, so such a
recommendation would be a disservice to developers.

It could be done, or at least approximated, by finding the current basic
em size, watching for theme changes, and setting or changing spaces as
appropriate. However, that's a lot of code which may be unnecessary by 3.0,
and a theme could specify different fonts for different widgets.

And a fixed number of em-widths may not be appropriate. It may be better
to have, for example: 6 em-widths for small fonts, 5 for a middle range
of font sizes, and 4 for very large fonts. Nobody's really looked at this
yet, as far as I know.


> [1]
> http://developer.gnome.org/projects/gup/hig/1.0/layout.html#window-layout-spacing
> 
> [2]
> http://developer.gnome.org/projects/gup/hig/1.0/images/layout_callouts.png
> 


Cheers,
Greg