Multitouch on the MacBook Air and Beyond

[sjamaan]

But the hardware doesn't report two independent presses, it reports the average. That's because many implementations can't reliably sense two independent presses (e.g. if you place two fingers on the same horizontal, even if apart, then it can't locate them independently), so the average is a useful abstraction.

Here's an intresting experiment: hold one finger still on the touchpad and move the other one up or down. You'll notice that this gesture is recognised as two-finger scrolling. It's not just the average that is reported, because scrolling would then occur at half speed, which is not the case. However, it's still possible the touchpad 'feels' something moving and detects two fingers without registering the relative and absolute positions of the fingers. Position detection is a requirement for gestures like pinch and rotate.
I think the question is "can our current hardware detect the position of a finger on the trackpad, or does it just register movement?"
Three finger-swiping must be possible using our current hardware because this gesture requires only movement detection, and we know our trackpads can detect the difference between one, two or three fingers.

 

[samh004]

I should think even if Apple doesn't introduce this in 10.5.2 for the rest of us, it should be supported if someone knew which files were necessary to copy over.

Maybe, just maybe, the three-fingered gesture wont work, but there's no reason the pinch/expand and rotate shouldn't work.

I think the question is "can our current hardware detect the position of a finger on the trackpad, or does it just register movement?"

This will be answered as soon as someone pulls apart the MBA and compares the trackpad part number to the existing MB/P's part numbers.

 

[TBi]

But the hardware doesn't report two independent presses, it reports the average. That's because many implementations can't reliably sense two independent presses (e.g. if you place two fingers on the same horizontal, even if apart, then it can't locate them independently), so the average is a useful abstraction.

If two fingers are on the same horizontal then it can tell the difference by looking at the vertical scale. Remember you have both X and Y coordinates. The X might be the same but as long as the Y is different the trackpad knows where it is.

The limitation isn't really in the trackpad itself, but more in the interface between the trackpad and the mainboard. If the interface only sends the co-ordinates it's current/newest touch then multitouch won't work. If it sends the co-ordinates of every single touch then multi touch will work.

I'd say the macbook trackpad could almost do 4 finger touching.

<SNIP>I think the question is "can our current hardware detect the position of a finger on the trackpad, or does it just register movement?"<SNIP>

Every trackpad only registers position the position of your finger. It's the cpu which reads the changing positions and translates this into movement on the screen.

Basically as you move your finger across the pad it gives off X,Y coordinates like this

(1,0) ... (1,1) ... (1,2) ... (1,3)

and the cpu moves the mouse cursor appropriately

 

[blackie]

Try this.

1) i) Place two fingers in line vertically = scrolling works.
ii) Place a third finger in line horizontally with any of those two fingers = scrolling works (as long as you move all three at the same distance)
iii) Place a third finger anywhere else = scrolling doesn't work.

2) Same is true if you flip fingers 90degrees, initially placing two fingers in a line horizontally.


3) i) Place two fingers diagonally from each other = scrolling works
ii) Place a third finger in line with both fingers (finnish the triangle) = scrolling works
iii) Place a third finger anywhere else = scrolling doesn't work.

4) Place three fingers on the same axis = scrolling doesn't work

5) place four fingers to form a square/rectagle = scrolling works

Must be something to do with the way the touch pad recognizes separate contact points using x and y axes. Where a third contact point is recognized on either axis scrolling no longer works. The pad recognizes a third contact point however... does it know where it is?

 

[davidtmarquez]

question is, why do we even fuss about three finger-ed scrolling?

I mean, there is only ONE thing you can do with three fingers on a trackpad.
I'd hope more on the rotation and pinching features.

 

[blackie]

Here's an intresting experiment: hold one finger still on the touchpad and move the other one up or down. You'll notice that this gesture is recognised as two-finger scrolling. It's not just the average that is reported, because scrolling would then occur at half speed, which is not the case. However, it's still possible the touchpad 'feels' something moving and detects two fingers without registering the relative and absolute positions of the fingers. Position detection is a requirement for gestures like pinch and rotate.
I think the question is "can our current hardware detect the position of a finger on the trackpad, or does it just register movement?"
Three finger-swiping must be possible using our current hardware because this gesture requires only movement detection, and we know our trackpads can detect the difference between one, two or three fingers.

Try moving one finger up and one finger down at same speed = they cancel each other out. One faster than the other and scrolling occurs. Actually it seems scrolling stops when two independent movements are recognized and the resulting movement is slight gaps in recognition.

 

[Don.Key]

If this is only software issue and apple will artificially block old hardware from enabling it, I am almost 100% sure that 3rd party products like steermouse will go around that.

 

[Vinnie_vw]

Well us iBook users got screwed on the two-fingered right-click for nearly two years after the Intels came out. Any software/driver-hack was blocked also as Apple patented the method and threatened any hacking company into submission. In Leopard it finally works, just a software-change.

So don't expect Apple to play nice this time either. Judging by their past behaviour, you'll either have to get a new Macbook or wait for the next OSX-upgrade. And I seriously doubt that the cheap Macbook revisions will see that feature anytime soon. If anything, they'll try to upsell people the pros, but they don't want people to pay anything less than the Air.

 

[TBi]

Try this.

1) i) Place two fingers in line vertically = scrolling works.
ii) Place a third finger in line horizontally with any of those two fingers = scrolling works (as long as you move all three at the same distance)
iii) Place a third finger anywhere else = scrolling doesn't work.

For point (ii) the touch pad can't actually see your third finger because of the way the touch pad works. Remember the touchpad takes readings at only two edges of the pad (left and bottom say). When you touch the pad it creates a change in the pad which is picked up somewhere along the left edge and somewhere along the bottom edge. So it can't see a point where the other two fingers cross.

For point (iii) the third finger isn't hidden by the other two and so the trackpad sees it. That's why it doesn't scroll any more.

Well us iBook users got screwed on the two-fingered right-click for nearly two years after the Intels came out. Any software/driver-hack was blocked also as Apple patented the method and threatened any hacking company into submission. In Leopard it finally works, just a software-change.

I had two finger scrolling working on my iBook with iScroll2.

 

[avincent52]

Mad props for the Macrumors upgrade.

I was so busy trying to get my MBP to work (long story) that I never even thought to look for the advanced trackpad features.

I'll use scroll and control click more than swipe or rotate, so I'm a happy camper.

best
Allen

 

[spinko]

one finger, two fingers,...

don't you all think that the MBA would have been much more innovative with a swivel screen on which one could point, pull, pinch and more directly on the objects and not through a trackpad ?? But then it probably would have been more expensive ... but innovative..

 

[zedsdead]

It's a shame that when people actually get the interview Jobs they don't ever ask him any questions that are really worthwhile. Why not press him about the Macbook and Macbook Pro being able to upgrade to the new Touchpad Features? Granted, he probably won't answer, but he at least may say, "It's just not possible."

As for the multi-touch features, the most useful seems to be the folder scrolling.

I really would like Apple to introduce some sort of multi-touch mouse.

 

[Thomas Harte]

It's not just the average that is reported, because scrolling would then occur at half speed

It is on my Core Duo MacBook Pro. Similarly, if I put one finger down then put another down on the far end of the pad then the cursor moves according to half the vector between them. Indeed, even my old titanium Powerbook does the second thing, for as long as the touchpad still works at all.

If two fingers are on the same horizontal then it can tell the difference by looking at the vertical scale.

Not always. Some touchpads use capacitance across the pad to measure how far away from each edge the finger is, rather than using a matrix based approach.

What I'm saying is: it depends on the exact make and operation method of the touchpads in the existing laptops. It's not necessarily possible, from a touchpad-only hardware point of view, from a connection between the touchpad and computer point of view and from a software running the touchpad point of view.

Also relevant, I note that Synaptics (who make most, maybe all (?) Apple touchpads) have announced 'multitouch' touchpads at CES 2008 and report that it requires a firmware patch. If the patch does extend to the touchpads used by Apple, and Apple don't want to give us the functionality, then don't expect a third party application to be able to enable it. It won't be as simple as hooking some internal driver signals that Apple are ignoring, as enabling two finger scrolls was.

 

[Manic Mouse]

Yes, it would be good. But it wouldn't be for a long time even if they do. Those new features are part of the macbook air at the moment and they will only keep them there to sell it. it's marketing.
a similar thing happened with the 5g ipod and ipod classic. They are both exactly the same hardware wise, but apple have kept the newer gui on the clasic so that you have more of a reason to buy the classic and not keep your 5g.

And guess what, with the Zune MS upgrade old models to new firmware! I would love to have the new interface on my iPod...

 

[wonderkid]

How about a multi-touch mouse?...

I still prefer to move the cursor using a mouse, but love the two finger scrolling on my Macbook and imagine the MacBook Air multi-touch will be even better. How about a mouse that replaces the scroll wheel and button area with a trackpad?

 

[TBi]

It is on my Core Duo MacBook Pro. Similarly, if I put one finger down then put another down on the far end of the pad then the cursor moves according to half the vector between them. Indeed, even my old titanium Powerbook does the second thing, for as long as the touchpad still works at all.

You are looking at this the wrong way. The computer sees the first press and moves the mouse to their. Now it sees the second press as if your hand had moved very quickly to another part of the touchpad and it moves the cursor accordingly. That's all, no more no less and no averaging.

If it only moves have the vector between them then that is because of mouse acceleration.

Not always. Some touchpads use capacitance across the pad to measure how far away from each edge the finger is, rather than using a matrix based approach.

The capacitance type pads also use a matrix system (except for the ipod scroll wheel but that's a different beast).

The capacitance changes the harder you press the pad so if it worked like you are saying then pressing down harder and softly will move the cursor. It doesn't work this way.

Resistive and capacitive pads both use a matrix to read the values, they just measure them a different way.

 

[elcid]

Someone start rooting through Terminal. It has got to be there with a simple 0 or 1 in order to get it to work. The touch can do it, it can defiantly distinguish all of the multi-touch gestures.

 

[dfunct]

I've got a quick question I hope someone can answer. Why has no-one hacked an iPod touch or an iPhone to be able to act as a multi touch input device for OSX yet?

 

[sjamaan]

Well us iBook users got screwed on the two-fingered right-click for nearly two years after the Intels came out. Any software/driver-hack was blocked also as Apple patented the method and threatened any hacking company into submission. In Leopard it finally works, just a software-change.

I had no idea two-finger right clicking works on older iBooks in Leopard. This gives me hope for the future regarding multitouch on current macs.

So don't expect Apple to play nice this time either.

I agree. When the iPhone was first announced, Jobs told how many patents there were in it. I forgot the exact number, but judging by that, they'll certainly have thought about third party applications trying to steal the technology if it's software based, because it's is the essence of the iPhone's interface. An official update, however, is possible by the time multitouch becomes less state-of-the-art, I think.

 

[TBi]

Someone start rooting through Terminal. It has got to be there with a simple 0 or 1 in order to get it to work. The touch can do it, it can defiantly distinguish all of the multi-touch gestures.

Even if the pad supports it, you'll need a whole new driver to make it work. You'll have to base it off the MBA's one (like iScroll2 was based off the powerbooks) and make it work on a regular MB/MBP.

It isn't as simple as a 0/1.

 

[TBi]

I've got a quick question I hope someone can answer. Why has no-one hacked an iPod touch or an iPhone to be able to act as a multi touch input device for OSX yet?

First you'd have to hack it to behave like a mouse and send the right signals over the cable for OSX to pick it up as a mouse, or also write a driver for OSX to make it think it's a mouse.

Then you'd have to hack it so the screen would send the right information to the mac.

They probably haven't done it because it's just hard. Though not impossible

 

[dfunct]

First you'd have to hack it to behave like a mouse and send the right signals over the cable for OSX to pick it up as a mouse, or also write a driver for OSX to make it think it's a mouse.

Then you'd have to hack it so the screen would send the right information to the mac.

They probably haven't done it because it's just hard. Though not impossible

Actually I was thinking of making it behave a bit more like a mini tablet ...

 

[eddx]

I really want this feature on my MBP

When Apple introduced two finger scrolling on the trackpads of the MacBooks it wasn't on the MBP for a couple of months but it was introduced later as an update.

Fingers crossed this comes to the whole laptop line

 

[TBi]

Actually I was thinking of making it behave a bit more like a mini tablet ...

You'd have to follow more or less the same process anyway

 

[techgeek]

...I'd love to see an external multi-touch trackpad accessory that can be used with desktop Macs as well as laptops though. Something matching the design of the new iMac keyboard would be great...

I second that!
Steve if you're reading this (and we all know you do) release a USB multitouch trackpad. You'll sell at least 2 of them

It would be awsome to use a device like that on my iMac. Much better than a mouse.