Two independent fragilities each collapsed the shape→shape morph back to
a grow-from-dots, which is why it only sometimes worked.
The hold was 600ms against an arrival whose timing is DECODE time: the
same track costs ~5ms once the session holds its waveform in memory but
hundreds of ms to over a second on the first cold decode. 2000ms covers
the cold case with room; fresh-stream searches take well past that, so
the loading story still gets the lane.
And the hold bailed on a bar-count mismatch — but the lane's width follows
the song TITLE now, so switching between a long and a short name resizes
the lane mid-gap and the guard threw the held shape away. Held and morphed
heights are refitted to the new count instead (nearest neighbour — it is a
moving start point, on screen for under a second).
Four consecutive cached switches measured after the fix: minimum lane
height 15.1 on every one (dots are ~2, the old dip hit ~5). Gapless
playback is untouched — the hold and morph are pure painting, and the
sink-append path never waits on the lane.
The arrival morph honestly started from whatever the lane showed — and on
a track change the lane always showed dots, because the waveform empties
the moment the queue moves. Every switch therefore played the same
grow-from-zero, when the picked motion was one waveform transforming into
another.
A track change now HOLDS the outgoing shape for ARRIVE_HOLD_MS (600ms),
painted in unplayed grey since the new track owns the transport. A quick
arrival — a local file, a cached stream — lands inside the hold and the
morph runs directly from the old bars into the new ones; a slow stream
load falls to the dots-and-swell story when the hold expires, exactly as
before. The rail mirrors the hold with the same shared constant, and
suppresses the loading swell while holding so the keyframes cannot fight
the held heights.
Measured across a cached track switch: the lane's mean height never left
16.9-17.4 (the dots sit at 2, the old dip hit 5.2) while the per-column
fingerprint changed — the shape transformed without ever falling.
Chosen on waveform-arrive.html (M2, direct morph, 1000ms): when a track
has its whole waveform at once — a local file, a fully-cached stream, or
the final decode replacing a stream's progressive peaks — every bar eases
from whatever the lane currently shows straight into the new shape, all
together. From the resting dots that reads as a uniform grow; from a
mid-sweep swell or the previous track's bars it is literally one waveform
transforming into another. The streaming rise keeps its left-to-right
story untouched; the morph fires only on a peaks swap at coverage 1, and
never on a resize, which re-lays the same shape and stays instant.
The canvas keeps a record of what it actually painted last frame — dots,
swell, rise, morph or settled — so the morph always starts from the truth
on screen, and the fade colours (accent, boundary blend, hover wash) stay
live through it. The rail mirrors the motion in CSS: an `arriving` class
carries the same 1000ms house-ease height transition, placed after the
rise rule so a stream's final decode arrives on this ease too.
Measured live on a cached start: bar heights walked 5.2 → 8.2 → 10.6 →
12.3 → 13.6 → 14.6 → 15.0 and settled at 15.1 at the 1000ms mark — the
ease-out curve, frame by frame.
The source chips are gone — the rail already tells that story — and with
them the measured slot, its effects, and the bar's only container query.
The now-playing cluster hugs the song name with no cap, giving ground only
once the scrubber hits its 260px floor; the artist's 55% ceiling applies
only when an album sits beside it, so a lone loading artist no longer
renders as two letters in a twelve-pixel box.
The waveform is rebuilt on honesty. WAVE_BUCKETS rises 400 → 2000 (~128ms
per bucket — at 400, every display bar was ~2s of audio averaged twice),
and one shared shaping in waveshape.js replaces both lanes' gain-into-clamp
rule, which flat-topped 53.8% of the bars on a real decode and was propped
up by per-bar noise in the rail — deleted; the lane shows the record, not a
hash of the bar index. Bars fold with a mean+peak blend and stretch across
the track's own p05–p97, so a loud master stops pinning to the ceiling and
a quiet one stops vanishing.
The playbar copies the rail's fade verbatim: whole bars blend accent→grey
with cuts landing in the 4px gap, and the one bar under the playhead
crossfades toward whatever its neighbours are — the wash while hovering,
the muted grey otherwise. The redraw gate watches that blend instead of a
0.75px playhead move, so both lanes now step on every position event.
Loading is drawn, not implied: the solid fallback bar is gone and the lane
is always the bars, always seekable. Empty, it rests as the rail's dots; a
swell crosses them while a waveform is computed (2s sweep, 0.5s rest); a
streaming track's bars stand up left→right on a 40ms cadence, each rising
over 2s. The rise frontier is the waveform's OWN coverage, reported by
stream_waveform beside the peaks — the old contract zero-padded partial
peaks to full length and let the UI fold them against a fresher byte
count, which stretched the whole shape between refreshes. Where the bars
end is how much of the track has actually loaded; cached and local tracks
arrive at coverage 1 and pop in complete. The first partial is also
requested eagerly (fresh refresh clock per track, 700ms retries until
peaks exist), closing most of the audio-before-lane gap.
KeelrLeek