On Mon, 14 Mar 2016 14:44:34 +0200 Pekka Paalanen <ppaala...@gmail.com> wrote:
> On Sat, 12 Mar 2016 11:33:40 -0800 > "Jasper St. Pierre" <jstpie...@mecheye.net> wrote: > > > I have to bring this up, because it's not necessarily true. There's > > something you're missing. After working on embedded SoCs, I realize > > that a lot of them put the YUV video plane *behind* the main RGB > > plane. This allows them to do subtitles and OSD controls over the > > video without stacking it RGB -> YUV -> RGB, as you might imagine. > > Oh my. > > > Thankfully, some of these systems allow you to put the video on top of > > RGB, but not all. Some even just have two YUV planes (for > > picture-in-picture) and one RGB plane on top, not even a cursor plane. > > > > On embedded systems where they have fullscreen control, they simply > > render alpha-graphics into the RGB window, and then stack a YUV plane > > behind it to blend against. > > > > Wayland, in its current subsurface architecture, can't support this > > system, unfortunately. The best thing I could think of here was to > > have Wayland consider a punch-through when it sees a YUV plane stacked > > under an RGB one from the same client, and it knows the scanout is > > ARGB. But maybe that's too auto-magical. > > > > I think that could work, but the implementation would need to be > > tricky about all the special cases, if we cared enough to make those > > work, e.g. surfaces under the punch-through need to be knocked out, > > but surfaces above can't be, since they're stacked on top. And that > > implies surfaces under the punch-through can't themselves use > > overlays, etc. > > I don't think it should be *that* hard, but of course I'm only talking > from Weston implementation point of view. FYI, I've filed https://phabricator.freedesktop.org/T7351 Thanks, pq
pgpBjcwCJF9Me.pgp
Description: OpenPGP digital signature
_______________________________________________ wayland-devel mailing list wayland-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/wayland-devel
