The previous axis swapping code would oddly rely on the input coordinates
remaining on untransformed device coordinates, while those are gotten on
screen coordinates (hence rotated), this would cause swapping not to kick
in, and result in swapped X/Y scaling to be applied to X/Y ranges.
So make the axis swapping code be calculated upon screen coordinates, as
the collected points already are, and swap the applied scalings if
necessary.
Also, the code that swapped coordinates before returning to the caller
would scramble min/max values when swapping x/y. Fix that too, minimum
and maximum should stay like that when swapping axes.
https://bugzilla.gnome.org/show_bug.cgi?id=732442
Calibration must be performed based on the device w/h ranges and the
screen size, so in which coordinates the monitor is virtually mapped
matters little on device coordinates. This fixes calibration of devices
attached to a monitor elsewhere than (0,0) in the screen.
https://bugzilla.gnome.org/show_bug.cgi?id=719574
Copies over files from a trimmed version of xinput-calibrator and
modifies the Makefile.am to build the program as a seperate utility.
This is just to verify the functionality of the code when built with
gnome-control-center.
https://bugzilla.gnome.org/show_bug.cgi?id=657423
