Re: How should Touchscreen Input Drives behave (OpenEZX pcap_ts)

Andy Ross
2006-05-18T16:17:43Z

Harald Welte wrote:
> 0) What kind of X/Y/Pressure values should I return? Are they supposed
> to be scaled to the X/Y resolution of the LCD? As of now, I return
> X_ABS, Y_ABS and PRESSURE values between 0 and 1000 (each).
>
> However, the coordinates are actually inverted, so '0,0' corresponds
> to the lower right corner of the screen, whereas '1000,1000' is the
> upper left corner. Shall I invert them (i.e. return 1000-coord')?

The native driver reports pressure as either 65535 or 0, and doesn't
(seem to) scale the x/y values at all. The uncalibrated values and
180 degree rotation (actually, my phone shows a slight rotation error
or a few pixels) are definitely reported to user space without
modification.

A matrix-based recalibrator will handle any orientation so long as the
corners are known, and so long as you report a pressure of zero
meaning "pen up" everything should be compatible regardless of the
units you choose.

Andy