Touchpad's absolute touch coordinates

Question

Is it possible to read input directly from a Alps touchpad? I am trying to turn my touchpad into a cheap drawing tablet so I need to read the raw unprocessed x and y coordinates of where it was touched relative to the physical touchpad. So if I touch the bottom left corner of the touchpad, it should correspond to (0,0) etc.

I am trying to do this with Windows by the way.

I can already do this with a Synaptics touchpad, but that's only because Synaptics has a nice SDK that gave me full control of the device. I couldn't find a similar thing for Alps. Is there anyway to do this using the windows api or directinput or whatever?

Answer 1

Sorry but the Alps driver is really limited, it doesn't even give you a way to turn it off (so annoying sometimes!) Unless you are into reverse-engineering the DLLs that ship with it (hard) or writing a filter driver to capture the input directly (even harder) I would suggest just using a Synaptics device if you really want to go that route.

Apart from that would to be to grab the processed XY coordinates - this is an example in C#. Try that first, it is quite easy and maybe it will be precise enough.

Or just buy a drawing tablet, it could be cheaper depending on the time you could spend trying to make your (much smaller) touchpad do kinda the same thing but not very well.