Re: [Usability] Modifiers + Scroll => Zoom, which modifiers to use?

[Jody Goldberg <jody gnome org>]

On Tue, May 31, 2005 at 11:43:23AM +0100, Calum Benson wrote:
> On Tue, 2005-05-31 at 01:36, Dave Ahlswede wrote:
> 
> > So we're *really* locking a standard here.
> 
> There's been a guideline in the HIG about this for ages:
> 
> http://developer.gnome.org/projects/gup/hig/2.0/input.html#mouse-buttons
> 
>         Ctrl-scrollwheel-up should zoom into the window or control under
>         the mouse pointer, and Ctrl-scrollwheel-down should zoom out.
>         Zooming in this way should not move keyboard focus to the window
>         or control being zoomed.
> 
> There's also a remark in the draft version that Shift-scrollwheel should
> probably scroll a window horizontally.

Things are more complex than what the HIG addresses.

1) Some mice have both horizontal and vertical scroll wheels.
2) It is useful to support horizontal and vertical scrolling even
   with only one wheel
3) MS uses ctrl-wheel to adjust zoom
4) There are app specific scroll wheel operations.  The HIG should
   be clear what modifiers are available.
5) It should be clear how modifiers interact

As an additional data point Gnumeric does the following in order of
precedence :
    META	transpose direction
    SHIFT	application specific
    CTRL	increase/decrease magnification (in steps of 15%)

That leaves shift, and shift-ctrl as app specific chords