Survey about the Touchscreen

Al Johnson openmoko at
Sat Nov 22 15:39:59 CET 2008

On Saturday 22 November 2008, Anton Persson wrote:
> > > If you want those applications then you
> > > need to have some sort of keyboard. When the Ilume keyboard is active
> > > you only have perhaps 60% left of the screen. That means your
> > > application only have _half_ a VGA display. This practically eliminates
> > > the pro that people here have been bringing up, the full VGA display.
> >
> > The Psion's only half-VGA and it works fine there. The Psion does make
> > better
> > use of the screen space, but that's an application issue.
> Which means that you would still be happy if you had a slightly bigger
> display and a slightly thicker stylus, right?

Probably not. I found the lack of precision on the iPhone intensely irritating 
when I tried it. I also found that my touches were often not registered, 
probably because I am used to tiny fingertip or fingernail touches that work 
well on resistive screens. The G1 seemed to behave similarly. I could 
probably relearn my touchscreen use, but the loss of precision would be a 
constant background irritant and will preclude the use of small target areas 
that the high pixel density makes possible. Perhaps it's due to years of 
Psion use, but I'm almost as accurate with a fingernail as I am with a 

> Maybe even happier if you could use both
> your thumbs to push buttons on the on-screen keyboard. (For shift/alt keys
> etc. But of course, that could be solved by adding a couple of more real
> buttons..)

That would be good, but would be multipointer not simply multitouch. The 
iPhone can't do it if the guitar-type apps are anyting to go by. Now MPX is 
in mailline xorg we could support that, but I don't know that there's any 
touchscreen hardware available that can track multiple fingers independently. 
I don't think it's a technical problem to make one, but that's a conversation 
we've already had.

> > > If you think I'm wrong, could you please tell me in which situations
> > > you really
> > > could use application X or Y on your OpenMoko? And I mean in a
> > > situation where you would not have easy access to your EeePC in your
> > > back-pack.
> >
> > Exactly the same situations where I use them on the Psion, probably more
> > because I would carry it in situations where even the Psion is too big.
> > When
> > I first got the Psion I found myself using it in many more situations
> > than I
> had expected, simply because it was there and it worked.
> OK, that's a convincing example to me.  But I'm not convinced that a
> capacitive
> screen+stylus would prevent you from doing the same things. The iPhone has
> a bigger display but is in total smaller than the OpenMoko, and correct me
> (again) if I'm wrong, but aren't there some sort of word-processor for the
> iPhone too?

The problem for me is the mismatch between the high DPI of the screen and the 
precision of the touch detection. The capacitive touchscreen would prevent us 
from making full use of the display capabilities.

From a pure usability point of view changing from resistive to capacitive has 
upsides and downsides.
+ More robust
+ Multitouch possible
- Reduced precision
- Requires relearning for habituated resistive screen users.
From my experience so far the downsides outweigh the upsides, but extended use 
may change my mind.

> > > On the other hand, if you add a multi touch capable LCD panel, then you
> > > would
> > > enable software developers like myself to develop a whole range of new
> > > applications that are _not_ possible on a desktop or on the current
> > > OpenMoko...
> > > Applications that you will never see on the current OpenMoko.
> > >
> > > (I'm still not ruling out the possibility of a multi touch enabled
> > > resistive screen,
> > > but I never heard of such a thing...)
> >
> > I've never seen a commercial one, but I don't think it presents too many
> > technical hurdles. unfortunately Openmoko aren't big enough to push a
> > manufacturer to make such a thing, unlike Apple.
> True, which means we will probably never see a resistive multi touch
> enabled screen on an OpenMoko...
>     Best regards
>       Anton

More information about the community mailing list