Re: Multitouch on FR ... imho should be possible to mimic
The Digital Pioneer wrote:
It's tough to say until someone tries it. I don't have the GUI expertise
to do anything of the sort, but I'd love to see someone try it.
Testing is easy - no expertice needed.
Edit /etc/X11/Xserver
You'll find the parameter list for the xserver under a GTA02 (or GTA01)
heading. Currently, it is:
ARGS=$ARGS -dpi ${DPI} -screen ${SCREEN_SIZE} -mousetslib -hide-cursor
-root-ppm /usr/share/pixmaps/xsplash-vga.ppm vt1
Remove the -hide-cursor, then restart X or just boot the thing.
You will now get a visible mouse cursor, shaped like a X. It always move
to wherever the touchscreen driver believe you're touching the screen.
Touch the screen, the X moves under your finger. Lift your finger, and
you'll see it. Touch or drag with a stylus, and you'll see the mouse
cursor move around. Just like on a PC screen.
Now touch down with two fingers, and see the mouse cursor move/jump to
somewhere inbetween. That is what the touchscreen driver sees, that is
what software can _try_ to interpret as a gesture.
Try it, see for yourself. Do the midpoint seem stable enough to resize
a window? If not, is it at least stable enough to detect a rough
gesture? Do it slide wildly as you move your fingers?
I just tested myself.
With firm pressure, the cursor stays between my fingers. There is some
hight-frequency jitter as firmly pressed fingers slide - this can
probably be filtered out.
With normal light pressure and one moving finger, the cursor slides back
and forth between the midpoint and the stationary finger. Apparently,
the moving finger almost disapper at times. The cursor is always closer
to the stationary finger. No surprise - it is natural to apply more
pressure with a stationary finger. Especially if the device is hand-held.
If I hold two fingers on the screen, I can move the cursor back and
forth between the two positions with precision, by varying finger
pressure. One could control a 2D sidescroll game this way, except it'd
be way easier to just use the stylus for direct control.
Helge Hafting
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Re: Multitouch on FR ... imho should be possible to mimic
You saw this, didn't you: http://lists.openmoko.org/pipermail/community/2009-March/044481.html r -- | risto h. kurppa | risto at kurppa dot fi | http://risto.kurppa.fi ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
That's an excellent point, Helge. I just tried it, and it works quite well. The cursor doesn't go exactly to the midpoint, but I would say it's definitely usable data. It moves almost exactly as expected. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
This has been discussed multiple times since last ~15months. The basic assumption a middle-point when touching with 2 fingers might be anyway exactly in the middle is incorrect. It depends on pressure of each touchpoint. There have been many different opinions about feasibility of this approach, I for one think it won't work. cheers jOERG Am Do 19. März 2009 schrieb Yaroslav Halchenko: Hi All, I've been cherishing the idea for a while but got no spare time to even code a proof of concept. so I decided to share it with you so someone could do that for the common advantage ;) Indeed we can't register both touches -- as a result hardware returns midpoint. BUT what if you touch screen with two fingers (at some inter-finger distance like half of screen width) not at the same time but within lets say 100-200ms. Ie you click with one finger just slightly before the other one. then driver reports 2 coordinates where there is a significant immediate jump from first coordinate to the midpoint between the two, which would be as much as 1/2 of distance between the fingers. such behavior would signal that 2 fingers are on the screen! then if you move 2nd finger somewhere, midpoint would move and that movement can be taken as a multitouch gesture, ie if you are expanding 2nd finger away from first one -- it is like 'zoom-out' or increase of smth. analogously, by comparing to the first coordinate (of 1st finger) rotations / horizontal zoomin/ vertical zooming etc could be derived multitouch gesture mode would stop when fingers leave the screen or there is once again a singificant jump from prev coordinate (like you raise one finger up prior to the other one) alternative mode can be that after 'two finger' non-synchroneous touch which switches to multitouch mode you drive your gesture with only second finger (ie raise the first one off the screen) -- that would allow for better control over the gesture since no averaging of coordinates between two points would happen. And again, multitouch mode is left whenever finger is raised of the screen. if someone is to implement/test such approach, qwo might be a nice code base to start from... alternatively I guess tslib for those with debian+fbdev xserver. -- .-. =-- /v\ = Keep in touch// \\ (yoh@|www.)onerussian.com Yaroslav Halchenko /( )\ ICQ#: 60653192 Linux User^^-^^[17] ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community signature.asc Description: This is a digitally signed message part. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
It's tough to say until someone tries it. I don't have the GUI expertise to do anything of the sort, but I'd love to see someone try it. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
--- On Tue, 3/24/09, Joerg Reisenweber jo...@openmoko.org wrote: This has been discussed multiple times since last ~15months. The basic assumption a middle-point when touching with 2 fingers might be anyway exactly in the middle is incorrect. It depends on pressure of each touchpoint. There have been many different opinions about feasibility of this approach, I for one think it won't work. --- On Tue, 3/24/09, The Digital Pioneer digitalpion...@gmail.com wrote: It's tough to say until someone tries it. I don't have the GUI expertise to do anything of the sort, but I'd love to see someone try it. I have seen this thread long as well. I am not sure what you are trying to do because I have not read all the mails, but for simple tasks the middle-point when touching with two fingers works... you need to use your imagination when developing with multi touch in your minds. For Linball I simply use the middle-point when touching with two fingers to be able to use both flippers to try to do trapping, and that works fine. So just use the middle for multi touch, write code to test and you will realize out how to use multi touch for your purposes with this behavior. If you were talking in another idea completely different, my apologies for this OT :) Regards, Rafa ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
Stefan Monnier wrote: FWIW, there's another source of info that might be used: jitter. When you have two fingers pressed, not only the reported position is more-or-less the middle point, but it's also jittery. So you could detect such jitter as a tell-tale of multitouch and then use the jitter itself (orientation and magnitude) as an indicator of the actual position of the fingers. Whether it would be sufficiently reliable to be used, I don't know. Unfortunately, the jitter has many interpretations. * The user is moving the fingers apart * The user is moving the fingers together * The user holds the finger still, but pressure varies You may be able to get a decent multitouch with one limitation - the first finger stay still. With that limitation, the first finger establish some base point (the point to rotate around, or the point that stand still when something is resized.) When the second finger comes down it does all the movement, and its location is at any time twice as far out from the base as the midpoint the FR actually register. Well, perhaps a bit less than twice as far out, as pressure probably is higher for the stationary finger. Helge Hafting ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
Unfortunately, the jitter has many interpretations. * The user is moving the fingers apart * The user is moving the fingers together * The user holds the finger still, but pressure varies I think the jitter you should see with multitouch should be quite different from finger moves: much higher frequency. Stefan ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Multitouch on FR ... imho should be possible to mimic
Hi All, I've been cherishing the idea for a while but got no spare time to even code a proof of concept. so I decided to share it with you so someone could do that for the common advantage ;) Indeed we can't register both touches -- as a result hardware returns midpoint. BUT what if you touch screen with two fingers (at some inter-finger distance like half of screen width) not at the same time but within lets say 100-200ms. Ie you click with one finger just slightly before the other one. then driver reports 2 coordinates where there is a significant immediate jump from first coordinate to the midpoint between the two, which would be as much as 1/2 of distance between the fingers. such behavior would signal that 2 fingers are on the screen! then if you move 2nd finger somewhere, midpoint would move and that movement can be taken as a multitouch gesture, ie if you are expanding 2nd finger away from first one -- it is like 'zoom-out' or increase of smth. analogously, by comparing to the first coordinate (of 1st finger) rotations / horizontal zoomin/ vertical zooming etc could be derived multitouch gesture mode would stop when fingers leave the screen or there is once again a singificant jump from prev coordinate (like you raise one finger up prior to the other one) alternative mode can be that after 'two finger' non-synchroneous touch which switches to multitouch mode you drive your gesture with only second finger (ie raise the first one off the screen) -- that would allow for better control over the gesture since no averaging of coordinates between two points would happen. And again, multitouch mode is left whenever finger is raised of the screen. if someone is to implement/test such approach, qwo might be a nice code base to start from... alternatively I guess tslib for those with debian+fbdev xserver. -- .-. =-- /v\ = Keep in touch// \\ (yoh@|www.)onerussian.com Yaroslav Halchenko /( )\ ICQ#: 60653192 Linux User^^-^^[17] ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
I have wondered if this was possible before, and I don't see why it can't be implemented, but it is limited as the only motion it could really detect (I would think) is moving the fingers closer or further, and if you move both fingers apart at the same rate, the midpoint doesn't move, so you have to know how to use it right. Still, I'd like to see it implemented, since it should (in theory) work once you get used to it. Just my 2 cents... ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
you can do rotation as well -- just a little bit of 'logic' to decide either it is a linear or circular motion (of 2nd finger in respect to the 1st one) On Thu, 19 Mar 2009, The Digital Pioneer wrote: I have wondered if this was possible before, and I don't see why it can't be implemented, but it is limited as the only motion it could really detect (I would think) is moving the fingers closer or further, and if you move both fingers apart at the same rate, the midpoint doesn't move, so you have to know how to use it right. Still, I'd like to see it implemented, since it should (in theory) work once you get used to it. Just my 2 cents... ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community -- .-. =-- /v\ = Keep in touch// \\ (yoh@|www.)onerussian.com Yaroslav Halchenko /( )\ ICQ#: 60653192 Linux User^^-^^[17] ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
Ahh, right, of course. You just have to remember to keep one finger still. :) ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
that is why may be 2nd way (raising 1st finger up after 2nd reached the screen, so there are 2 jumps in coordinates: d/2, and d/2 in a single direction) might be preferable way -- then you drive your 'multitouch' mode with any gesture you like while assuming that 'other' finger is still in the original position... actually it can be two separate modes 1. two fingers on screen -- use for moving 2. 2nd finger on screen -- rotation, whatelse ;) I think clever solution can jump between the two of them (depending on either you again put 1st finger back on the screen)... just a little tiny state machine ;) On Thu, 19 Mar 2009, The Digital Pioneer wrote: Ahh, right, of course. You just have to remember to keep one finger still. :) ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community -- .-. =-- /v\ = Keep in touch// \\ (yoh@|www.)onerussian.com Yaroslav Halchenko /( )\ ICQ#: 60653192 Linux User^^-^^[17] ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Multitouch on FR ... imho should be possible to mimic
FWIW, there's another source of info that might be used: jitter. When you have two fingers pressed, not only the reported position is more-or-less the middle point, but it's also jittery. So you could detect such jitter as a tell-tale of multitouch and then use the jitter itself (orientation and magnitude) as an indicator of the actual position of the fingers. Whether it would be sufficiently reliable to be used, I don't know. Stefan ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
