Per the owner's idea: instead of moving the banner out of the per-screen header
(which would change its position), remember the banner's "life stage" and resume
it on the next screen. The engine already keeps the message + rotation timing;
this adds the scroll offset:
- bannerEngine tracks the in-flight scroll (target, duration, start). On attach,
if a scroll is still running, it computes the current offset and calls the new
host's resumeScroll(fromTx, toPx, remaining) — the view jumps to the carried
offset and continues to the end over the remaining time, instead of restarting
at the left.
- A finished scroll is left at its end; the rotator's own loop then takes over.
Verified: spot-checked in the browser (a long message at offset -785 resumes at
-788 on the next screen, not 0) and unit-tested (attach mid-scroll calls
resumeScroll with a partial offset and the remaining duration).
The previous engine kept the scheduler running but the view re-`show()`-ed the
current message on every (re)mount, replaying the fade on each navigation — which
looked like the cycle restarting (especially for a single message). Now:
- A mounted AdBanner reads the engine's live message (bannerCurrent) and renders
it immediately, with no fade; attach no longer re-shows. Only a real advance
fades. Verified: opacity stays 1.0 across a navigation, message preserved.
- The fade is manual opacity on a .fadewrap layer (not transition:fade), kept
independent of the scroll (inner track transform), so a long message still
fades at both ends and a {#key} remount cannot force an intro fade.
- A viewport size change (portrait↔landscape) re-measures the current message
(remeasureBanner on resize/orientationchange, debounced) so the scroll
re-evaluates for the new width — the owner accepts the restart on resize.
Rotator gains restart(); engine gains bannerCurrent()/remeasureBanner().
Engine continuity + remeasure unit-tested.
Banner UX refinements (owner feedback):
- Position: render the banner inside Header (under the title) instead of in
Screen, so it sits in the same place on every screen. In the game the grown
nav's spare height now falls below the banner (banner under title, board
pinned to the bottom) — it no longer jumps to the game area.
- Continuity: move the rotation into a persistent module engine
(lib/bannerEngine) — the scheduler + timer live outside the components, so a
navigation (which remounts the view) continues the cycle instead of restarting
it. Each AdBanner only attaches as the DOM host and resyncs to the live message.
- Fades: a long, scrolling message now fades at both ends. The fade is a
{#if} transition:fade layer, independent of the scroll (the inner track's
transform), so the two no longer interfere.
Verified live (mock + Playwright): same position in lobby and game; the cycle
continues across lobby↔game; opacity sampling shows fade-out + fade-in for the
long message. Engine continuity unit-tested.
Ilia Denisov