RE: Re: Philips Dexscape TouchScreen Problem

["Keith Doxey" <ukha@xxxxxxxxxxx>]

Hi Darren,

I did some work on touchscreens a year or so ago.

They report their position as an absolute value that is the same
irrespective of resolution. Windows then takes this value and scales it
based on the actual display resolution that the machine is running and
converts it to a pixel coordinate.

Try running BOTH screens at the same resolution and it should then be
reasonable accurate.

You say you are cloning the display, but in reality you are scaling the
display as you are running different resolutions on both screens even
though
they look the same.

Quite how you overcome the problem, I dont know, but I hope I might have
hit
upon the cause.

When I was messing about with reading the touch screen in VB I got one of
the calculations wrond and flipped the touch screen top left corner to
bottom right. Was quite fun to try and press on the wrong bit of the screen
to get the button you wanted :)

Regards

Keith

> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx]On Behalf Of
> darren_karp2001
> Sent: 02 May 2006 09:41
> To: ukha_d@xxxxxxx
> Subject: [ukha_d] Re: Philips Dexscape TouchScreen Problem
>
>
> Something like that Phil, yes.
>
> As I said if I extend my desktop on to the touchscreen the
> touchscreen does nothing (apart from displaying the desktop of
> course), but if I clone it then the touchscreen works but its out of
> alignment. In the center of the screen it seems good but as you move
> out it gets worse.
>
> If I match the resolution to 1024 x 768 then at the lefthand side of
> the touchscreen its accurate but the further right I go the worst it
> gets!
>
> Very odd...and very annoying.
>
> Any tips?
> Darren
>
>
>
> --- In ukha_d@xxxxxxx, "Phil Harris" <phil@...> wrote:
> >
> >
> > > -----Original Message-----
> > > From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx]
> > > On Behalf Of darren_karp2001
> > > Sent: 02 May 2006 08:52
> > > To: ukha_d@xxxxxxx
> > > Subject: [ukha_d] Re: Philips Dexscape TouchScreen Problem
> > >
> > > Nice try Phil :)
> >
> > Why thankyou...
> >
> > > It's really rather weird. It appears from doing some basic
> > > research that when you extend a desktop on to a touchscreen
> > > monitor Windows no longer receives the input, but as a clone
> > > it works but as I said the alignment is WAY off (over an
inch).
> > >
> > > I'm thinking that it has something to do with the fact that
> > > the resolution of the main desktop is 1280 x 1024 and the
> > > touchscreen is 1024 x 768 but that shouldn't really matter
> > > I would have thought.
> >
> > I'm assuming that the touchscreen driver probably reports its
> coordinates
> > back on a scale of 1024 x 768 whereas you are feeding it a
desktop
> image
> > that is larger than that - does it at one corner get more
accurate
> whilst at
> > the diagonally opposite corner get further and further out?
> >
> > Phil
> >
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>