Anelok: save the slider !

Werner Almesberger werner at almesberger.net
Sun Aug 23 03:23:57 UTC 2015


Ron K. Jeffries wrote:
> Slider is OK concept, if it works.

Yes, that little "if" is the problem ...

> It's not clear to me what the proposed
> alternative is or how it would be used.

The alternative would be to add buttons (either micro switches
or domes) where the slider is now. With three buttons, you'd
have the same functionality as with the slider now, minus
sliding.

Comparison buttons (3 of them) vs. slider:

Attribute				Slider		Button
---------------------------------------	---------------	---------------
BOM cost				"free"		moderate / high
Response to dirt / aging		immune		degrade / fail
Mechanical load distribution		case top	PCB
(Unintended) activation threshold	low		medium
Signal processing			demanding	easy (debounce)
Tactile response			no		yes
Power consumption (when idle)		polling		none
Gestures, single touch			5		3 (5 ?)
	  multi touch			n/a		<= 4, may be messy

To scroll through a list, you'd press "up" or "down" repeatedly.
(There can be no auto-repeat because long presses are already
used for other functions.)

For example, when on the accounts list, the buttons are currently
assigned to the following functions:

Button	Tap			Long press	Very long press
-------	-----------------------	---------------	---------------
Top	Previous entry (up)	Setup (1, 2)	Setup (2)
Middle	unassigned		Select entry	Select entry
Bottom	Next entry (down)	Switch off	Zap session

(1) Would become "back" once directories are implemented and
    you're in a subdirectory.
(2) Or "Alert" if an asynchronous notification is pending.
    (Press "A" in the simulator to generate a radio alert.)

If you make a sliding movement while pressing on the slider,
fw/ui/input.c switches to slider mode and generates N pixels
up/down information.

You can play with all this in the simulator.

With more than three buttons, be it real or virtual (e.g., by
combining top/bottom and middle), auto-repeat would also be
possible. Going > 3 buttons may be get messy, though, given the
limited space.

> I am baffled as to how vi
> key bindings might be presented.

Ah, that's for the simulator:

Cursor key	vi key		Anelok slider area
---------------	---------------	------------------
Up		K		Top
Left		L		Middle
Down		J		Bottom

> Your note is very clever.

Thanks ! :)

- Werner



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