Re: Two finger scrolling

[Brett Lymn <blymn%internode.on.net@localhost>]

On Sun, Mar 15, 2020 at 11:00:09PM +0000, nia wrote:
> I've just committed a handful of changes to synaptics.c that give me
> smooth two-finger scrolling out of the box.
> 
> I'm curious how many others are using multitouch touchpads and whether
> you notice any improvement.
> 

I will have a look when I get a chance.  Just one question, what happens
if you place one finger on the touchpad and then place another on the
touchpad in a different area and move that second finger?  Does the
cursor move or do you get scrolling?  The answer "scrolling" in this
situation is bad.  Thinkpads have external buttons wired, some laptops,
including my fujitsu do not have any external buttons.  That is the
whole reason for the button emulation code because clicking a click pad
results in a left button event - that is all you get, to emulate more
buttons in this situation the region the finger in determines the button
pressed.  So, to navigate a menu the first finger down determines the
button then a second finger is used to navigate. 

> The existing approximation (sysctl hw.synaptics.finger_scroll...) wasn't
> working for me at all, tweaking hw.synaptics.finger_scroll-min either
> gave me no scrolling or registered normal mouse movements as scrolling
> 
> I suspect my fingers are significantly smaller than whoever wrote this
> code. Was anyone using this successfully, and how does scrolling compare
> after my changes?

What can I say? It worked for me.  One thing I have learnt is there is a
massive variation between laptop trackpads when it comes to reporting
the W value so values that work on one laptop are bad on others, I am
surprised that you were unable to get a fscroll_min that would work for
you.

-- 
Brett Lymn
--
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