61a99aff9d
Absolute devices may send relative events depending on the mode (synaptics by default, wacom per option). The relative events are added to the previous position, converted into device coordinates and then scaled into desktop coordinates for pointer movement. Because the device range must be mapped into the desktop coordinate range, this results in uneven scaling depending dimensions, e.g. on a setup with width == 2 * height, a relative movement of 10/10 in device coordinates results in a cursor movement of 20/10 (+ acceleration) Other commonly user-visible results: * the touchpad changing acceleration once an external monitor as added. * drawing a circle on a wacom tablet in relative mode gives an ellipsis in the same ratio as the desktop dimensions. Solution: pre-scale the incoming relative x/y coordinates by width/height ratio of the total desktop size. Then add them to the previous coordinates and scale back with the previous mapping, which will undo the pre-scaling and give us the right movement. X.Org Bug 31636 <http://bugs.freedesktop.org/show_bug.cgi?id=31636> Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net> Reviewed-by: Keith Packard <keithp@keithp.com>
X Server
The X server accepts requests from client applications to create windows,
which are (normally rectangular) "virtual screens" that the client program
can draw into.
Windows are then composed on the actual screen by the X server
(or by a separate composite manager) as directed by the window manager,
which usually communicates with the user via graphical controls such as buttons
and draggable titlebars and borders.
For a comprehensive overview of X Server and X Window System, consult the
following article:
http://en.wikipedia.org/wiki/X_server
All questions regarding this software should be directed at the
Xorg mailing list:
http://lists.freedesktop.org/mailman/listinfo/xorg
Please submit bug reports to the Xorg bugzilla:
https://bugs.freedesktop.org/enter_bug.cgi?product=xorg
The master development code repository can be found at:
git://anongit.freedesktop.org/git/xorg/xserver
http://cgit.freedesktop.org/xorg/xserver
For patch submission instructions, see:
http://www.x.org/wiki/Development/Documentation/SubmittingPatches
For more information on the git code manager, see:
http://wiki.x.org/wiki/GitPage