[PATCH xserver 00/12] xwayland: Pointer confinement and warping

[Jonas Ådahl]

On Fri, Sep 09, 2016 at 10:38:32AM -0600, Keith Packard wrote:
> Peter Hutterer <peter.hutterer at who-t.net> writes:
> 
> > Keith, I think the ABI changes should go in before we lock down, this is a
> > pretty important feature for the Wayland transition and our release cycles
> > aren't exactly predictable at this point.
> 
> Yeah, the ABI changes look harmless enough, although I do wonder why the
> existing DDX interfaces for tracking the cursor aren't sufficient. For
> confining the cursor, we've already got the CursorLimits function which
> is called on every confine, and of course WarpPointer always calls
> SetCursorPosition.

Both those functions are called from places all over the place and we'd
have to do guess work in hw/xwayland to try to figure out when they were
actually just warps and not arbitrary cursor position changes, and when
a certain combination of CursorLimit arguments mean confineTo and not
something else.

ConfineTo is about asking the compositor to do limit cursor movements
for us, since Xwayland doesn't have the ability to do so. Trying to use
CursorLimits to try to guess when that happened as a result of a grab
with a confineTo seems just as fragile and hard to understand as trying
to use SetCursorPosition for detecting cursor movement happened to be a
result of a pointer warp, compared to just calling vfuncs for when those
things actually happened.


Jonas

> 
> -- 
> -keith