Implementing right click and middle click drag

Sagar Tewari iaansagar at
Sat Jul 14 12:16:34 UTC 2018


I'm adding states to implement the above changes and have a query regarding
the 'tap_event' enum. What do the enum values 'TAP_EVENT_THUMB,
Do they mean that a thumb or palm has been placed on the touchpad, or that
one of the touch locations is actually a thumb or palm? If latter is the
case, what does the value 'TAP_EVENT_PALM_UP' mean?

On Sat, Jul 14, 2018 at 3:09 PM Sagar Tewari <iaansagar at> wrote:

> Hi,
> This is the proposed design of state machine for implementing right click
> drag as double tap followed by a single tap. I intend to implement the
> middle tap drag in a similar way. The new stuff in inside the dashed
> boundaries. This is the intended behaviour:
> 1. A double tap followed by a single tap and move will act as a right
> click drag.
> 2. If drag lock is enabled, the user will have to tap to end the right
> click drag.
> Please review it and let me know of any required modifications.
> On Thu, Jul 12, 2018 at 8:22 AM Sagar Tewari <iaansagar at> wrote:
>> Thanks, I'll get myself working on it.
>> On Thu, Jul 12, 2018, 08:19 Peter Hutterer <peter.hutterer at>
>> wrote:
>>> On Tue, Jul 10, 2018 at 01:06:17PM +0530, Sagar Tewari wrote:
>>> > I would like to work on implementing right and middle click drag as
>>> > two/three finger tap followed by a single tap drag, the way it works in
>>> > synaptics driver. I found that this topic has been discussed
>>> previously:
>>> >
>>> >
>>> > But this was the single main on that topic in the archives.
>>> >
>>> > To Peter Hutterer, where can I find the patch being discussed in that
>>> mail?
>>> > Would it be better to start from scratch since the patch was apparantly
>>> > flawed?
>>> I've forwarded the attachments from that thread to you off-list.
>>> Basically, that patch was incomplete and didn't handle some states and
>>> transitions. It also wasn't documented clearly, in that it didn't explain
>>> what it *intended* to do. For hairy stuff like this, knowing what the
>>> intention was is more important than the code so we know what is a bug
>>> and
>>> what isn't.
>>> Note that the state machine is the main source of information here, the
>>> actual tapping code is just a bunch of switch statements based on the
>>> state.
>>> Cheers,
>>>    Peter
> --
> Best Regards
> Sagar Tewari

Best Regards
Sagar Tewari
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