[linux-audio-dev] Knobs / widget design (radial movement)

Lee Revell rlrevell at joe-job.com
Sat Jun 26 05:33:59 UTC 2004


On Fri, 2004-06-25 at 17:23, Fons Adriaensen wrote:
> On Fri, Jun 25, 2004 at 03:38:10PM -0400, Lee Revell wrote:
> > I think this is a lot of the reason European (especially Dutch) design
> > is so much more advanced than American.  In the States, a fire exit sign
> > says 'EXIT'.  In the Netherlands, it is an icon that unmistakably means
> > 'this way out', without any text required.  This is *much* harder to do
> > than just 'EXIT' in big red letters, but required.  If there is a fire 
> > in Amsterdam for example, you will have people from 5-10 different
> > countries running for the exit.
> 
> Yes, that's true. I remember driving in the US, and how I found it very 
> odd for all the roadsigns to tell me in plain English what I was or wasn't
> supposed to do. But 'graphic' signs can be completely useless as well.
> At work I have a telephone with something like 20 extra buttons besides
> the numeric keypad. They all have mysterious signs on them that defy both
> my imagination and logic reasoning. I'd much prefer for them to be labeled
> 'Hold', 'Transfer', etc. than by the totally uncomprehensible things there
> are now.  

It boggles my mind how little attention people who design phones
(ethernet/IP phones are the worst) give to usability.  I suspect that
most of them don't do usability test one.

Designing for usability is not rocket science.  For the phone example,
the options (in decreasing order of desirability) are:

	1. A self-explanatory pictorial representation.
	2. A text label.
	3. An incomprehensible pictorial representation.
	4. An incomprehensible text label.

Only 1 and 2 are acceptable.  If you can't find an icon that clearly and
unambiguously says 'Hold' (for example) then you MUST use a text label.

The question of whether an icon 'clearly and unambiguously' represents a
function MUST NOT be decided by the designer's intuition, but on REAL
USABILITY TESTS WITH REAL USERS.  Put a phone in front of 10 test
subjects, and have them 'put someone on hold'.  90% should go straight
for the right button.  Otherwise your design FAILS the usability test,
and you need a better icon.  Only when you have exhausted every
conceivable icon should you resort to a text label.

> > With regards to radial movement, the only self-explanatory way to do it
> > that I have seen is mousewheel-on-mouseover.  People will figure this
> > out with no documentation at all.  Please make your radial controls work
> > this way unless there is a good reason not to.
> 
> If you have a mousewheel :-)

I think the length and variety of responses to the basic question, "what
is an intuitive way to move a radial control with the mouse pointer" is
a compelling argument for getting a wheel mouse.

If the mouse wheel is not present, then you can fall back to whatever
behavior you want.  Most people will just use the wheel.

Lee




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