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

[Lee Revell]

On Mon, 2004-08-23 at 11:19, Paul Winkler wrote:
> On Sat, Aug 21, 2004 at 04:22:36PM -0400, Lee Revell wrote:
> > I suspect that a GUI programmer or interface designer would expect
> > things to increase from top to bottom.  In GUI programming, the origin
> > is at the top left of the screen, and X,Y coorinates increase going
> > right and down respectively.  I am not sure why they didn't just follow
> > the Cartesian conventions here, but I believe it has been this way
> > forever.
> 
> I believe it's a historical artifact of early GUI software being
> pretty close to the hardware. CRT screens put the origin at top
> left and scan from left to right, top down.

OK, so if I were to start writing the Linux Audio Human Interface
Guidelines based on all of the feedback from this post, I would say
something like the following.  I have used the type of language you
would find in an Internet RFC.

"Sliders MUST be operable with the mouse wheel.  This MUST only be
enabled when mousing over a slider, otherwise, the mouse wheel MUST
retain its normal behavior of scrolling the window.

For a vertical slider, rolling the mouse button away from you
(hereafter: wheel-up event) MUST increase the value of the parameter,
and wheel-down MUST decrease the value.

For a horizontal slider, wheel-up SHOULD increase the value, and
wheel-down SHOULD decrease the value by default.  However, this behavior
MUST be configurable system-wide.  If a system-wide facility to control
this is unavailable then the app MUST provide a configuration
mechanism."

Additional submissions are welcome.

Lee