The DVD player was the only thing still speaking a compositor the room
no longer runs. It asked sway's tree whether VLC's window had really
gone fullscreen, because VLC reports playing while its window is still
the black startup one the loading cover exists to hide.
VLC's own status was measured as a replacement and is not one: it
reports fullscreen true in the same 250ms poll as playing, because the
flag is the option it was started with and not a report about its
window. So the cover is held for a floor and capped by the deadline that
was already there, and the compositor is not asked anything.
Focus-or-launch went the same way. The session already takes an
exclusive lock, so a second one cannot start, and bringing an existing
one to the front is the panel's job.
classroom-window, classroom_sway and classroom_chrome are gone with it —
the last of them was reachable from nothing at all.
DVD also moves out of the status row, where it sat beside the clock as
though a disc were a machine reading. It is an application: it is in the
row with Wonder Ink and the browser, and classroom-provision removes it
from the layout on a machine with no optical drive, which retires
DVD_ENABLED. A computer that moves between rooms takes its drive with
it; nobody remembers to edit a file when it does.
The panel is rebuilt from the package at every login now. Plasma keeps
whatever panel it first built, so an update could change the bar in the
package and never change it in a room — measured, with an icon that
outlived the file it came from. Editing the live panel configuration was
tried instead and destroyed the panel, because the shell owns that file.
Removing it before the shell starts is safe and makes the desktop
stateless.
Co-Authored-By: Claude Opus 5 <[email protected]>
The readiness condition was playback state alone, and on a real disc
VLC reports playing well before its window has taken the screen. The
cover came off onto VLC's ordinary tiled startup window — black, sized
to everything except the dock's reserved strip — and the disc menu only
arrived afterwards. Exactly the state the cover exists to hide.
Ask sway instead. VLC only takes the display when its window goes
fullscreen, and the tree says when that happens. The cover now comes off
when VLC reports playing or paused, its window is fullscreen, and 800ms
have passed for the menu to draw its first frames. The playback check
runs first because it is local and cheap; the tree is only walked once
VLC claims to be playing something.
The twenty second deadline is unchanged: a cover with nothing behind it
is still the one outcome DVD mode must never produce.
Co-Authored-By: Claude Opus 5 <[email protected]>
Pressing DVD now enters DVD mode rather than opening VLC. VLC is still
the backend, because its dvdnav module is what decodes disc menus and
nothing else on Debian does that reliably, but nothing a person can see
or press belongs to it any more.
classroom-dvd-session owns the whole thing. It puts a full-screen black
layer-shell surface up the moment the button is pressed, starts VLC
behind it, and drops it once playback is actually on screen — so the
harsh cut from wallpaper to VLC's black window is gone, and no partial
VLC window or reserved dock strip is ever visible. A deadline drops the
surface regardless, because DVD mode must never leave a black screen
with nothing behind it.
The controls are a classroom bar on the overlay layer, the one layer
sway draws above a fullscreen window. It slides up when the pointer
reaches the bottom of the screen and hides again shortly after it
leaves. It is drawn from the dock's own stylesheet at the room's UI
scale, so it is the same surface, the same radius and the same white
icons. While hidden it only accepts the pointer in a thin strip along
the bottom edge, so a click on a disc menu goes to the disc.
The bar reaches VLC through an HTTP interface on loopback behind a
password generated per session, sending hotkey *actions* by name. That
is what makes the next part possible.
All 108 hotkeys VLC 3.0.23 defines are unset, then Space, Esc and the
arrow keys plus Enter are bound. Crop, aspect ratio, subtitles, audio
tracks and deinterlacing are no longer reachable by pressing a key at
random, and the arrow keys no longer change VLC's volume — the
television owns volume, and CEC will own it properly later.
Esc quits instead of leaving fullscreen. There is nothing to leave, and
leaving it was what stranded people on a black VLC window. Close, Eject
and Esc all ask VLC to quit and escalate to SIGTERM then SIGKILL if it
does not; when VLC exits by any route, including a crash, the session
ends and the classroom desktop comes back.
Verified against VLC 3.0.23 on Trixie: every argument accepted, every
control action accepted over the control interface, a wrong password
refused, and quit exiting cleanly. The surfaces were rendered under a
headless sway and screenshotted to check the bar against the dock.
Co-Authored-By: Claude Opus 5 <[email protected]>
