[vbox-dev] mouse integration concept level overview?

Huihong Luo huisinro at yahoo.com
Wed Nov 30 20:22:49 GMT 2011

Thanks for the clarification. Yes, I noted that, when absolute positing is enabled, mouse intergration works w/o additions, which is very nice !

--- On Wed, 11/30/11, Michael Thayer <michael.thayer at oracle.com> wrote:

From: Michael Thayer <michael.thayer at oracle.com>
Subject: Re: [vbox-dev] mouse integration concept level overview?
To: "Huihong Luo" <huisinro at yahoo.com>
Cc: vbox-dev at virtualbox.org
Date: Wednesday, November 30, 2011, 11:57 AM

This is correct.  However, the USB tablet is not related to the Guest 
Additions (although it is also used for mouse integration as it supports 
absolute reporting), so it doesn't fit into the same schema - instead it 
has to conform to the USB HID specification.



On 11/30/2011 07:39 PM, Huihong Luo wrote:
> Seems in UsbMouse.cpp, the tablet reports 0-0x7fff range, which is
> different from 0xffff, is this correct? I wanted to confirm this.
> Thanks,
> --- On *Tue, 9/6/11, Michael Thayer /<michael.thayer at oracle.com>/* wrote:
>     From: Michael Thayer <michael.thayer at oracle.com>
>     Subject: Re: [vbox-dev] mouse integration concept level overview?
>     To: "Huihong Luo" <huisinro at yahoo.com>
>     Cc: vbox-dev at virtualbox.org
>     Date: Tuesday, September 6, 2011, 12:19 PM
>     Hello Huihong,
>     On Tue, 2011-09-06 at 10:25 -0700, Huihong Luo wrote:
>      > I noted that Windows additions (vboxmouse.sys and VBoxMouseNT.sys)
>      > doesn't perform any conversion from this 0-FFFF percentange
>      > coordinates, however X11 additions convert them to screen resolution.
>      > Does Windows happen to use the same measurement of 0-0xFFFF ?
>     Yes, since we originally only supported Windows as a guest the Additions
>     and Host-to-Guest protocol were originally designed to work comfortably
>     with Windows. Note that X.Org has evolved/improved quite a bit over the
>     years - if you look at vboxmouse_15.c, which supports a range of
>     different "vintages" of X.Org, you will see that the older ones require
>     us to manually convert the values we read to pixel offsets, whereas the
>     newest let us specify the range of values we return and take care of all
>     the conversion for us. (With an off-by-half pixel error unfortunately
>     which we have to work around in the host code, but such is life.)
>      > Another thing is that the cursor shape at pointer disppears when
>      > moving out of vm guest window, does virtualbox perform some special
>      > task to make the curson not to appear? or the host simply reports
>     some
>      > out of range positions to the guest. I was curious how this is
>      > handled.
>     When mouse integration is enabled the software guest cursor is hidden,
>     and instead the host cursor tracks the shape that the guest cursor would
>     have. From the point of view of the Additions we are providing a
>     hardware cursor (most graphics cards provide a hardware sprite for this
>     purpose), and it is telling us where it should be and what shape it
>     should be. And obviously when the host pointer is not above the guest
>     window it simply takes on the shape requested by whatever other host
>     application it moves over next.
>     Of course, since we don't let the guest move the host cursor this only
>     works if the guest wants it to be where it is already, but since our
>     input driver is providing the position data this usually works.
>     Regards,
>     Michael
>      > --- On Fri, 9/2/11, Michael Thayer <michael.thayer at oracle.com
>     <http://us.mc1603.mail.yahoo.com/mc/compose?to=michael.thayer@oracle.com>>
>     wrote:
>      >
>      >
>      > From: Michael Thayer <michael.thayer at oracle.com
>     <http://us.mc1603.mail.yahoo.com/mc/compose?to=michael.thayer@oracle.com>>
>      > Subject: Re: [vbox-dev] mouse integration concept level overview?
>      > To: "Huihong Luo" <huisinro at yahoo.com
>     <http://us.mc1603.mail.yahoo.com/mc/compose?to=huisinro@yahoo.com>>
>      > Cc: vbox-dev at virtualbox.org
>     <http://us.mc1603.mail.yahoo.com/mc/compose?to=vbox-dev@virtualbox.org>
>      > Date: Friday, September 2, 2011, 1:47 PM
>      >
>      >
>      > Hello Huihong,
>      >
>      > On Thu, 2011-09-01 at 20:56 -0700, Huihong Luo wrote:
>      > > I need to know a bit more about the mouse integration. Can
>     someone explain in big picture on what happened when a mouse pointer
>     is moving from host to the guest? once the mouse inside the guest
>     window, host informs the guest about the mouse positions? etc.
>      > >
>      > > I need to get some ideas on this in order to implement the
>     drag-and-drop feature for vbox. Right now, it's stuck when the mouse
>     is dragged from host to vm, how the guest side knows about that. I
>     need to press a key for now to tell the guest side, so the dnd isn't
>     smooth yet. A good understanding on mouse integration would be very
>     helpful.
>      > > _______________________________________________ vbox-dev
>     mailing list vbox-dev at virtualbox.org
>     <http://us.mc1603.mail.yahoo.com/mc/compose?to=vbox-dev@virtualbox.org>
>     http://vbox.innotek.de/mailman/listinfo/vbox-dev
>      >
>      > I'm afraid that this will be a quick-ish explanation for now. When
>      > absolute pointer reporting is enabled (see the
>     VMMDevReq_GetMouseStatus
>      > VMM device request) the current pointer position can be requested
>     with
>      > the VMMDevReqMousePointer request. This is reported as a
>     percentage of
>      > the width and height (respectively) of the guest screen -
>     expressed as a
>      > value from 0 to 0xFFFF - or of the virtual desktop for multi-monitor
>      > guests. The host works out what percentage values correspond to the
>      > position of the host pointer relative to the host window the
>     machine is
>      > running in, and the Additions report the position back to the
>     guest in a
>      > way that the guest OS can convert to the correct pixel offset.
>     The host
>      > sends a VMM device event (basically an interrupt and a data word)
>     when
>      > absolute reporting is enabled or disabled and when new position
>     data is
>      > available.
>      >
>      > Hope that helps a bit.
>      >
>      > Regards,
>      >
>      > Michael
>     --
>     ORACLE Deutschland B.V. & Co. KG Michael Thayer
>     Werkstrasse 24 VirtualBox engineering
>     71384 Weinstadt, Germany mailto:michael.thayer at oracle.com
>     <http://us.mc1603.mail.yahoo.com/mc/compose?to=michael.thayer@oracle.com>
>     Hauptverwaltung: Riesstr. 25, D-80992 München
>     Registergericht: Amtsgericht München, HRA 95603
>     Komplementärin: ORACLE Deutschland Verwaltung B.V.
>     Hertogswetering 163/167, 3543 AS Utrecht, Niederlande
>     Handelsregister der Handelskammer Midden-Niederlande, Nr. 30143697
>     Geschäftsführer: Jürgen Kunz, Marcel van de Molen, Alexander van der Ven

ORACLE Deutschland B.V. & Co. KG   Michael Thayer
Werkstrasse 24                     VirtualBox engineering
71384 Weinstadt, Germany           mailto:michael.thayer at oracle.com

Hauptverwaltung: Riesstr. 25, D-80992 München
Registergericht: Amtsgericht München, HRA 95603

Komplementärin: ORACLE Deutschland Verwaltung B.V.
Hertogswetering 163/167, 3543 AS Utrecht, Niederlande
Handelsregister der Handelskammer Midden-Niederlande, Nr. 30143697
Geschäftsführer: Jürgen Kunz, Marcel van de Molen, Alexander van der Ven
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