[linux-audio-dev] mouse wheel behavior and RFC: human interface guidelines

[Lee Revell]

On Sat, 2004-08-21 at 14:45, Thorsten Wilms wrote:
> On Sat, Aug 21, 2004 at 06:35:44PM +0200, Melanie wrote:
> > Hi,
> > 
> > it's backwards in a "numerical" sense, in that the numbers increase with 
> > one slider type, but decrease with another, using the same command.
> > 
> > However, UI designers don't think in numbers, but associations.
> > 
> > Left is generally associated with up, right with down, as we read left to 
> > right, top to bottom. Therefore, up MUST map to left, down MUST map to 
> > right, otherwise, non-mathematically minded people get uttely confused.
> 
> I couldn't find anything on the web abou this.
> But I asume the behaviour was thought out for 
> scrollbars and transfered to sliders.
> 
> With scrollbars scrolling lets say a table, the vertical scrollbar 
> has top = start, bottom = end. Horizontal scrollbar left = start, 
> right = end. Wheeling up on vertical sliders means scrolling 
> toward the vertical start. Wheeling up on the horizontal slider 
> should therefor mean scrolling to the horizontal start -> scrolling 
> left.
> 

Very interesting.  You are probably correct. 

> But there's nothing to scroll with sliders. They're not about 
> a position in space.
> 
> Today might well have been the first time I used the wheel 
> on common sliders, and it felt backwards!
> 

Agreed.  I can understand why Microsoft (and thus QT and GTK) chose to
do it this way, but I bet audio users make MUCH heavier use of sliders
than almost anyone else.  So, an informal survey of Linux audio users is
actually pretty good data. 

> Fan-slider wheeling will stay as is, differing from QT and 
> GTK sliders. But I doubt the folks behind the toolkits would 
> listen and change wheeling direction.
> 

True, no reason to break it for people who are used to the old behavior,
and MS does do extensive usability testing.  However this NEEDS to be
made configurable system-wide.  This way CCRMA and AGNULA (for example)
can ship with the non-default slider behavior if their users prefer it.

Lee