I found some time to implement some of the features I want in the
synaptic touchpad. This is taken from synaptic.c:
I want to have more features :). Every touch pad (ps2 and serial) is now
be supported according to STIG and every feature/capability is read.
However there seems to be some very old serial touchpads that have an
advanced mode not mentioned in STIG.
Further I have added the following
Emulation of scrolling
The window drivers allow using the edge to emulate a wheel
mouse. When putting the finger at the right edge, a movement up or
down translates to wheel movement. Lift the finger again to operate
normally again.
Stick attached to a touchpad
Some touchpads have a stick "attached", so they share the same
port. In absolute mode the stick protocol is a simple ps2
protocol, except it is sent in an absolute packet. (In relative
mode both uses ps2)
Four buttons to work
Some touchpads have 4 buttons. Only 3 was read and the last was set
to up or down "button".
Multiple fingers
I have added an option to detect such by looking at pressure levels,
which is not that great. If the pad have the capability to detect
it, this is used instead, but this far from optimal. It does detect
two horizontal parted finger if in same vertical position, otherwise
the detection is bad. This is/was a problem as my wrist lays on the
laptop which gives a 45 deg to horizontal for my fingers. Now I try
to add further detections, which works for me in 95% of the time.
Multi finger tap
Using 1,2 or 3 fingers to make a tap translates into left, right or
middle button pressed. I originally thought about doing what is
called a "HOP" where after a quick finger shift the distance of the
hop decides which button is pressed. I dropped it partly because
synaptics did in version 3.2 and because it was harder than I
thought.
Multi finger less sensitive
Adding or removing a finger or just accidently touch the pad with
the palm while using the pad causes the pad to report the average
position between the touched places. This of cause gives annoying
erratic movements. When adding or removing fingers are detected
the mouse is stop for some small time to avoid this. This is not
perfect as the finger detection is not perfect, but it helps a lot!
Palm detection
Some touchpads tries to detect whether the reported data is from a
palm or similar. When reading this signal the movement is
stopped. Except the detection does not work very well :(
Enabling/disabling touchpad
A new corner action is to disable the touchpad. It is enabled again
by tapping the same corner. This is useful if I know I am going
to write a lot. The stick still works.
Debugging corner action
A corner action now allows toggling the debug information.
The structure has changed to handle both serial and ps2 touchpads. Many
variable names have changed.
The documentation referred to is from
"Synaptics TouchPad Interfacing Guide" revision 2.5
or just STIG
Peter
--
E-Mail: pebl@xxxxxxxxxx
Real name: Peter Berg Larsen
Where: Department of Computer Science, Copenhagen Uni., Denmark
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