Answering "how do I give you root": you don't. tools/plymouth-preview.sh
renders the splash — LUKS dialog included — into X11 windows in ~10s with
no reboot, no root and no DRM:
- unshare -rm = user + mount namespace; every mount dies with it.
- /run/plymouth is BOTH the socket dir and the compiled-in plugin path
(`strings plymouthd` → /run/plymouth/plugins/), so we bind a writable dir
over it AND recreate its symlinks — miss those and plymouth can't find
x11.so, silently skips X11 and reaches for a tty.
- never pass --tty (main.c:2133 takes the X11 path only while default_tty
is unset); /dev/dri is masked so a preview physically cannot mode-set a
real output — which matters on a docked session (#127).
- PLY_CREATE_FAKE_MULTI_HEAD_SETUP fakes 800x600 + 640x480 heads.
- debug wants plymouth.debug=stream: — `file:` buffers and yields nothing.
What it proved immediately: with a STABLE two-head canvas the current theme
centres correctly on both heads. So the geometry is fine and #137 really is
the timing bug (positions frozen at parse time vs a canvas that resizes
when a head arrives) — recorded in the item.
And it caught my own fix: hoisting positions into layout() rendered the
background on both heads and nothing else — no logo, no bar — with NO parse
error logged. Reverted rather than shipped, because that script draws the
passphrase box on an encrypted machine. #137 carries the failure, the prime
suspect (plymouth script scope: assignment lands in `local` unless the name
already exists) and the fast edit/render loop for the next attempt.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
