[PATCH] fixesproto v6: Pointer barrier thresholds
Peter Hutterer
peter.hutterer at who-t.net
Wed May 2 23:35:38 PDT 2012
On Thu, May 03, 2012 at 12:40:58PM +1000, Christopher James Halse Rogers wrote:
> On Thu, 2012-05-03 at 11:05 +1000, Peter Hutterer wrote:
> > On Tue, Apr 03, 2012 at 01:42:38PM +1000, Christopher James Halse Rogers wrote:
> > > ---
> > >
> > > I've got a corresponding xserver patch, but it needs updating for the
> > > Great Reindent of '12. Might as well get support for the protocol additions
> > > before fixing it up.
> > >
> > > A slightly different variant of this (it's gone through a number of iterations
> > > in conjunction with the Unity team) is used by the Unity shell as infrastructure
> > > for the one-launcher-per-display support, so there's evidence that it's a usable
> > > protocol.
> >
> > looks good, a few minor clarifications are needed below. The main change I'd
> > like to see is a change to use generic events instead of a standard event..
>
> I'll finish reading up on how to make that happen, then :)
>
> >
> > we've hit the maximum event number in the past, adding another non-generic
> > event can cause us to stretch over the limit.
> > http://lists.x.org/archives/xorg-devel/2010-March/006716.html
> >
> > > configure.ac | 2 +-
> > > fixesproto.txt | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > xfixesproto.h | 59 +++++++++++++++++++++++++++++++++++
> > > xfixeswire.h | 23 +++++++++++--
> > > 4 files changed, 173 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/configure.ac b/configure.ac
> > > index f85b802..07dd29a 100644
> > > --- a/configure.ac
> > > +++ b/configure.ac
> > > @@ -22,7 +22,7 @@ dnl
> > > dnl Process this file with autoconf to create configure.
> > >
> > > AC_PREREQ([2.60])
> > > -AC_INIT([FixesProto], [5.0],
> > > +AC_INIT([FixesProto], [6.0],
> > > [https://bugs.freedesktop.org/enter_bug.cgi?product=xorg])
> > > AM_INIT_AUTOMAKE([foreign dist-bzip2])
> > > AM_MAINTAINER_MODE
> > > diff --git a/fixesproto.txt b/fixesproto.txt
> > > index 5903ac9..6f8c705 100644
> > > --- a/fixesproto.txt
> > > +++ b/fixesproto.txt
> > > @@ -650,6 +650,100 @@ DestroyPointerBarrier
> > >
> > > Errors: Barrier
> > >
> > > +************* XFIXES VERSION 6 OR BETTER ***********
> > > +
> > > +13. Pointer Barriers Expansion
> > > +
> > > +This update extends pointer barriers to optionally allow the pointer through
> > > +when a threshold is reached. This can be useful for desktop environments that
> > > +wish to use a large region of the screen, such as an entire edge, to provide a
> > > +casual target while allowing determined movement to pass through.
> > > +
> > > +13.1 Types
> > > +
> > > + BarrierEvent: {Hit, ThresholdExceeded}
> > > + BarrierEventID: CARD32
> > > +
> > > +13.2 Events
> > > +
> > > +BarrierNotify
> > > +
> > > + subtype: BarrierEvent
> > > + window: WINDOW
> > > + event-id: BarrierEventID
> > > + barrier: BARRIER
> > > + velocity: CARD32
> > > + x, y: INT16
> > > + raw-displacement: FP1616
> > > + delta-t: INT16
> > > + deviceid: INT16
> > > +
> > > +13.3 Requests
> > > +
> > > +SelectBarrierInput
> > > +
> > > + window: WINDOW
> > > + event-mask: SETofBarrierEvent
> > > +
> > > +
> > > + This request directs barrier events to the named window. Subtype
> > > + indicates the trigger of the event, which is Hit when the barrier has
> > > + prevented pointer movement and ThresholdExceeded when the barrier has
> > > + been hit but has not prevented pointer movement due to the threshold
> > > + being exceeded.
> > > +
> > > + Barrier is the barrier on which the event was triggered. (x,y) contain
> > > + the coordinates of the pointer after restriction by any applicable
> > > + barriers, and velocity is the unrestricted instantaneous velocity
> > > + of the pointer, perpendicular to the barrier.
> >
> > how is velocity defined?
> > (edit: found it below, this should be either in some common section or
> > everywhere. You could just define a VELOCITY type and explain it there)
>
> That makes sense, I'll do so.
>
> >
> > > +
> > > + deviceid is the identifier of the device which caused the barrier
> > > + event, raw-displacement and delta-t are the raw valuator (purpendicular
> >
> > I'm not sure what you raw-displacement here is, can you clarify?
> >
>
> Raw-displacement is exactly the value you'd get if you were subscribed
> to XI 2 raw events and selected the valuator perpendicular to the
> barrier.
>
> It (and delta-t) are here so that a client can get a pre-acceleration
> idea of the velocity and user behaviour if the client desires. This is
> useful for clients to determine when they want to release the barrier.
Two questions:
Is this really enough then? don't you need x and y to determine that?
Compare a movement of -10/0 against a vertical barrier with a movement of
-10/-70. The former is almost certainly trying to push through, the latter
is almost certainly trying to move north, but wobbling a bit.
(also, raw event data is in FP3232, iirc)
second - is the raw driver data enough? isn't the accelerated data of more
interest since it maps much more against what the user is trying to do?
I have no clue what data the driver submits, but I have a rough feeling of
how much the mouse will move when I do.
> > s/valuator/valuators
> > typo: purpendicular
> >
> And I thought I'd spell-checked it. Oops :).
>
> > > + to the barrier) and time-since-last-input-event for deviceid
> > > + respectively.
> > > +
> > > + event-id is an identifier for this barrier event. A barrier event
> > > + begins when the pointer is first restricted by the barrier, and ends
> > > + with the first mouse event that is not restricted by the barrier.
> >
> > event-id is unique per-device? per-server? per-something?
> > I assume the second, given that device id isn't required to release the
> > pointer, might be worth pointing out.
>
> Unique per-barrier per-server, modulo wrap around. I'll make this
> clearer.
>
> >
> > > +
> > > + In the case of multiple overlapping barriers an event is sent for each.
> > > +
> > > +CreatePointerBarrierVelocity
> > > +
> > > + barrier: BARRIER
> > > + drawable: DRAWABLE
> > > + x1, y2, x2, y2: INT16
> > > + directions: CARD32
> > > + velocity: CARD32
> > > + devices: LISTofDEVICEID
> > > +
> > > + Creates a pointer barrier along the line specified by the given
> > > + coordinates on the screen associated with the given drawable. This
> > > + has identical semantics to CreatePointerBarrier, except that the
> > > + barrier created will not block the pointer if the threshold
> > > + velocity is exceeded. The velocity is measured in px/sec perpendicular
> > > + to the barrier.
> >
> > should state that px/sec is after acceleration is applied (i suspect that's
> > the case) just to make sure that's clear
>
> Yup.
>
> >
> > > +
> > > + Once the pointer has been stopped by the barrier it will remain blocked
> > > + for the duration of the barrier event.
> > > +
> > > + Errors: IDChoice, Window, Value, Device
> > > +
> > > +BarrierReleasePointer
> > > +
> > > + barrier: BARRIER
> > > + event-id: BarrierEventID
> > > +
> > > + Temporarily allow the pointer to pass through a pointer barrier.
> > > + This disables the barrier for as long as event-id is valid - that is,
> > > + as long as the pointer remains in contact with the barrier.
> > > +
> > > + Requests to release the pointer for an event-id which is not current
> > > + are silently ignored.
> > > +
> > > + Errors: Barrier
> > > +
> > > +
> >
> > is there a need for this to take a number of event-ids?
> > corner-case, certainly, I admit.
>
> Hm. Given that I've earlier said that in the case of multiple
> overlapping barriers an event is sent for each, this might indeed be
> necessary.
>
> To properly support multiple overlapping barriers I think there'd need
> to be changes elsewhere. Specifically, if a single pointer event is
> blocked by multiple barriers the server sends out an event for each
> barrier, but the client has no way of knowing whether that's a response
> to a single pointer movement or not.
>
> This could easily be supported by adding an extra field to the
> BarrierEvent for the number of subsequent events triggered by the same
> pointer event.
>
> I'm not sure if this is worth doing.
if you use GenericEvents you have space and you can pack all Barriers hit by
a single pointer movement into the same event.
>
> >
> > > 99. Future compatibility
> > >
> > > This extension is not expected to remain fixed. Future changes will
> > > diff --git a/xfixesproto.h b/xfixesproto.h
> > > index fcf409a..4e2d3d6 100644
> > > --- a/xfixesproto.h
> > > +++ b/xfixesproto.h
> > > @@ -532,6 +532,65 @@ typedef struct {
> > >
> > > #define sz_xXFixesDestroyPointerBarrierReq 8
> > >
> > > +/*************** Version 6.0 ******************/
> > > +
> > > +#define BarrierEventID CARD32
> > > +
> > > +typedef struct {
> > > + CARD8 type;
> > > + CARD8 subtype;
> > > + CARD16 sequenceNumber B16;
> > > + Window window; B32;
> > > + BarrierEventID event_id B32;
> > > + Barrier barrier;
> > > + CARD32 velocity B32;
> > > + INT16 x B16;
> > > + INT16 y B16;
> > > + CARD32 raw_displacement B32;
> > > + CARD16 delta_t B16;
> > > + CARD16 deviceid B16;
> > > +} xXFixesBarrierNotifyEvent;
> >
> > see generic event comment
> >
> > > +typedef struct {
> > > + CARD8 reqType;
> > > + CARD8 xfixesReqType;
> > > + CARD16 length B16;
> > > + Barrier barrier B32;
> > > + Window window B32;
> > > + INT16 x1 B16;
> > > + INT16 y1 B16;
> > > + INT16 x2 B16;
> > > + INT16 y2 B16;
> > > + CARD32 directions;
> > > + CARD32 velocity;
> > > + CARD16 pad B16;
> > > + CARD16 num_devices B16;
> > > + /* array of CARD16 devices */
> > > +} xXFixesCreatePointerBarrierVelocityReq;
> > > +
> > > +#define sz_xXFixesCreatePointerBarrierVelocityReq 32
> >
> > it'd be great to shoehorn this into the existing request but I suspect that
> > has a potential to break things. so reluctantly ack
>
> It'd be a SMOP to have the server/libxfixes use a different request
> based on whether or not both sides support fixes v6, but that would be
> an extra piece to get wrong.
yeah, and nasty. I suspect we have enough requests left in xfixes to not
worry about this yet :)
Cheers,
Peter
> > > +
> > > +typedef struct {
> > > + CARD8 reqType;
> > > + CARD8 xfixesReqType;
> > > + CARD16 length B16;
> > > + Window window B32;
> > > + CARD32 eventMask B32;
> > > +} xXFixesSelectBarrierInputReq;
> > > +
> > > +#define sz_xXFixesSelectBarrierInputReq 12
> > > +
> > > +typedef struct {
> > > + CARD8 reqType;
> > > + CARD8 xfixesReqType;
> > > + CARD16 length B16;
> > > + Barrier barrier B32;
> > > + BarrierEventID event_id B32;
> > > +} xXFixesBarrierReleasePointerReq;
> > > +
> > > +#define sz_xXFixesBarrierReleasePointerReq 12
> > > +
> > > +#undef BarrierEventID
> > > #undef Barrier
> > > #undef Region
> > > #undef Picture
> > > diff --git a/xfixeswire.h b/xfixeswire.h
> > > index 432349a..0230595 100644
> > > --- a/xfixeswire.h
> > > +++ b/xfixeswire.h
> > > @@ -48,7 +48,7 @@
> > > #define _XFIXESWIRE_H_
> > >
> > > #define XFIXES_NAME "XFIXES"
> > > -#define XFIXES_MAJOR 5
> > > +#define XFIXES_MAJOR 6
> > > #define XFIXES_MINOR 0
> > >
> > > /*************** Version 1 ******************/
> > > @@ -89,8 +89,12 @@
> > > /*************** Version 5 ******************/
> > > #define X_XFixesCreatePointerBarrier 31
> > > #define X_XFixesDestroyPointerBarrier 32
> > > +/*************** Version 6 ******************/
> > > +#define X_XFixesCreatePointerBarrierVelocity 33
> > > +#define X_XFixesSelectBarrierInput 34
> > > +#define X_XFixesBarrierReleasePointer 35
> > >
> > > -#define XFixesNumberRequests (X_XFixesDestroyPointerBarrier+1)
> > > +#define XFixesNumberRequests (X_XFixesBarrierReleasePointer+1)
> > >
> > > /* Selection events share one event number */
> > > #define XFixesSelectionNotify 0
> > > @@ -111,8 +115,6 @@
> > >
> > > #define XFixesDisplayCursorNotifyMask (1L << 0)
> > >
> > > -#define XFixesNumberEvents (2)
> > > -
> > > /* errors */
> > > #define BadRegion 0
> > > #define BadBarrier 1
> > > @@ -136,4 +138,17 @@
> > > #define BarrierNegativeX (1L << 2)
> > > #define BarrierNegativeY (1L << 3)
> > >
> > > +/*************** Version 6 ******************/
> > > +
> > > +#define XFixesBarrierNotify 2
> > > +
> > > +#define XFixesBarrierHitNotify 0
> > > +#define XFixesBarrierThresholdExceededNotify 1
> > > +
> > > +#define XFixesBarrierHitNotifyMask (1L << 0)
> > > +#define XFixesBarrierThresholdExceededNotifyMask (1L << 1)
> > > +
> > > +#define XFixesNumberEvents (XFixesBarrierNotify+1)
> > > +
> > > +
> > > #endif /* _XFIXESWIRE_H_ */
> > > --
> > > 1.7.9.1
> >
> > _______________________________________________
> > xorg-devel at lists.x.org: X.Org development
> > Archives: http://lists.x.org/archives/xorg-devel
> > Info: http://lists.x.org/mailman/listinfo/xorg-devel
>
>
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