cocoa devdraw: use gestures by default

Remove swipe gestures.
Keep only 2-finger pinching and 3-finger tapping.

[rsc, 2012-01-16 22:31:11]

I am not sure about this particular set of gestures.
I like the pinch for full screen and the 3-tap for middle
click, given that 2-tap is already right click.
However, the swipes really seem to come out of left
field, and they are acme-specific.  I am inclined
to drop them all.  The cut/copy/paste already have 
keystroke shortcuts anyway.

A cleaner way to accommodate chording would be if
you could, while holding one finger on the trackpad,
put down a second finger to make a 1+3 chord, and
then when you let go, you're back to just 1.
Similarly putting down two extra fingers would give 
a 1+2 chord, and starting with three fingers and
raising two would give a 2+1 chord.  I don't know if
that is possible, but it means I don't have to learn
extra magic swipes: once I know how to do l, m, r
clicks, I know how to combine them.

Is that possible?

Thanks.

[djeannot24, 2012-01-18 15:26:36]

I removed swipe gestures. Consequently, you can
forget the 2 Acme patches regarding undo and
argtext.

(I pulled plan9port in between, so Codereview's
"Delta from patch set" between 2 and 1 is
meaningless: a problem I had not foreseen. We must
use "Side-by-side diffs" instead.)

I think your chording idea would be hard to
implement. For example, if you put 3 fingers at
the "same time", the trackpad could still register
that your left finger touched the device first,
and so, as you prepared yourself for a 2+1,
you end up with a 1+2.

Initially, I also thought using my trackpad like a
mouse, but I came to the conclusion that a
trackpad was not like a mouse. I think that
chording was an excellent idea for mouse but that
swiping is more natural for trackpad.

I stopped using a mouse since the end of August,
and I find the combination of Acme + trackpad
delightful, and far more convenient than the
combination of Acme + mouse (that I am using right
now, because of my problem with Codereview). Of
course, one must activates the "dragging with drag
lock" option to make a trackpad useful.

But I recognize that my swipe code is just a hack.
I think the ideal would be to forward gesture
events to p9p apps (with a gestures.h,
initgestures(), etc.) and let them do whatever
they want with these events.

But I would be not at all shocked by Acme's using
of swipes with trackpad, chords with mouse, and
shortcuts with keyboard. They are just different
kind of devices.

[rsc, 2012-01-18 15:30:32]

What kind of events does the trackpad send
if you do a 3-tap and then take two fingers off?

I am not worried about interpreting a 3-tap as
a 1+2 tap because the trackpad already contains
logic to tell those apart, right?  I mean, 3-taps
work right now without being misinterpreted.
I wouldn't want to replace that recognition logic
but I wonder if the trackpad is sending us
event data that we could use directly.

Thanks.
Russ

[djeannot24, 2012-01-18 17:09:17]

Cocoa sends us the following high level events:
swiping, pinching, and rotating. After a 2-tap,
Cocoa sends us a mousedown event immediately
followed by a mouseup event. After a 3-tap, cocoa
sends us no high level event currently.

So we use low level "touch" events to recognize
3-taps.

Each touch event represents the status of 1
finger. Each time the status of 1 finger changes,
we receive an event for each finger on the
trackpad with its current status: down, up, moving
or stationary.

Here is the 3-tap implementation:

	switch eventstatus
	case fingerdown
		n = getnfinger
		if n is 3
			start timer
			tapping = 1
		if n > 3
			tapping = 0
	case fingermove
			tapping = 0
	case fingerup
		n = getnfinger
		if n is 0
			if tapping and timer<400msec
				sendclick 2

	$PLAN9/src/cmd/devdraw/cocoa-screen.m:/^gettouch

Here is the Apple documentation:

	http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/EventO...

Tell me if I misunderstand you.

[rsc, 2012-01-21 03:27:03]

LGTM

[rsc, 2012-01-21 03:44:36]

*** Submitted as a8c5d2dcba94 ***

devdraw: enable gestures on OS X

Remove swipe gestures.
Keep only 2-finger pinching and 3-finger tapping.

R=rsc
CC=plan9port.codebot
http://codereview.appspot.com/5498094

Committer: Russ Cox <rsc@swtch.com>

[marius.eriksen, 2012-02-01 16:32:27]

Another possibility for 2-1 is 3-fingers + physical click. Since physical clicks
are the 1 button, this is pretty consistent: 3-finger tap is 2 button, then the
click for the 1 (while the 3 fingers are still there).


On 2012/01/18 15:30:32, rsc wrote:
> What kind of events does the trackpad send
> if you do a 3-tap and then take two fingers off?
> 
> I am not worried about interpreting a 3-tap as
> a 1+2 tap because the trackpad already contains
> logic to tell those apart, right?  I mean, 3-taps
> work right now without being misinterpreted.
> I wouldn't want to replace that recognition logic
> but I wonder if the trackpad is sending us
> event data that we could use directly.
> 
> Thanks.
> Russ

[marius.eriksen, 2012-02-01 16:33:25]

(I agree with David that gestures really are different from mouse buttons -- but
it seems simpler to maintain reasonable analogies, unless we get 1st class
gesture support in devdraw that can be passed along to the application)

[djeannot24, 2012-02-01 17:56:16]

> However, the swipes really seem to come out of left
> field, and they are acme-specific.

> A cleaner way to accommodate chording would be [...]

My opinion is that chording also is Acme-specific
(but maybe I am mistaken), and that Acme's
chording is limited. Here an email I sent to Russ:

I used Acme's chording for 4 years. During that
time, I perceived those 3 limitations:

1) If you have previously selected some text, you
can't easily cut it with the mouse. You must
either reselect it, click on 'Cut' somewhere or
use the keyboard.

2) If you have previously selected some text, you
can't easily copy it with the mouse. You must
either reselect it, click on 'Snarf' somewhere or
use the keyboard.

3) If you have previously selected some text, you
can't easily replace it with the mouse. You must
either reselect it, click on 'Paste' somewhere or
use the keyboard.

With the swipe gestures, I do:

1) swipe-left anywhere in the Acme window

2) swipe-up anywhere in the Acme window

3) swipe-right anywhere in the Acme window

And I see no more limitation. All the editing is
done easily with the trackpad.

What delighted me when I discovered Acme was that
I could use it during 10 minutes before to realize
that I was using the wrong keyboard layout: so
much things could be done with just the mouse!

I think It's even more true with the trackpad.

I can even pilot Acme with my other hand now :)

The problem with swiping is that, since OS X Lion,
we don't receive swipe events anymore, unless we
change the default configuration, because a swipe
event means 3-finger, and Lion uses 3-finger by
default for Mission Control, etc.

I hope Apple will soon find a solution. A simple
one would be:

If the system uses 3-finger swipes, a swipe event means 4-finger.
If the system uses 4-finger swipes, a swipe event means 3-finger.