<div dir="ltr">Then I'd like some stronger wording in this patch that dictates that unmapping and remapping a surface by either destroying the xdg_surface or attaching a NULL buffer should be indistinguishable. No "hidden state", either accessible or inaccessible to the app (such as stacking order, window position, or user-added hints or settings) should leak through an unmap/map cycle, if such wording hasn't been added already.</div><div class="gmail_extra"> <div class="gmail_quote">On Sun, Jul 16, 2017 at 11:32 PM, Jonas Ådahl <<a href="mailto:jadahl@gmail.com" target="_blank">jadahl@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Sun, Jul 16, 2017 at 11:16:25PM -0700, Jasper St. Pierre wrote: > (Coming into this one late) > > When I first wrote xdg-shell, I maintained that attaching a NULL buffer > should be illegal since it has no benefit compared to destroying the > surface, but compositors might not reset all data attached to the surface, > making a weird exception where clients depend on bugs where state isn't > always reset. And the "resetting of all data" might seem like strange > behavior to clients. > > Has this rationale changed? Pretty much. It was never specified anywhere so implementations differed (weston and mutter implemented it like that but not sure anyone else did), it contradicted some wording in wayland.xml and it was a behaviour disliked by some, thus a middle ground was reached that clearly defines it as no state should be kept. I intend to try to make sure at least libweston-desktop and mutter respects this fully. Jonas <div class="HOEnZb"><div class="h5"> > > On Tue, Jul 11, 2017 at 8:11 PM, David Edmundson <<a href="mailto:davidedmundson@kde.org">davidedmundson@kde.org</a>> > wrote: > > > > > > >> The idea is that having unmapped by null-attach means the > >> xdg_surface/xdg_toplevel etc is reset to the exact same state that it > >> had when first created, thus to map again, one would do what one would > >> do the same as when mapping it for the first time: set up the state > >> (set_title, (set_maximized?), set_app_id), commit, wait for configure, > >> then attach a new buffer given the configure event data. > >> > >> > >> Thanks, I'd totally forgotten the commit as I was only looking in this > > interface. > > It's clear now. > > > > David > > > > _______________________________________________ > > wayland-devel mailing list > > <a href="mailto:wayland-devel@lists.freedesktop.org">wayland-devel@lists.freedesktop.org</a> > > <a href="https://lists.freedesktop.org/mailman/listinfo/wayland-devel" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/wayland-devel</a> > > > > > > > -- > Jasper </div></div></blockquote></div> <div> </div>-- <div class="gmail_signature" data-smartmail="gmail_signature"> Jasper </div> </div>