An iOS-style focus pull: the thing arrives out of focus and the blur fades
off it as the opacity comes up. Opacity leads the blur (full opacity around
45%, blur still lifting), which is what separates it from a cross-fade.
Ships on tabs (440ms), agent windows (560ms), the terminal pane (520ms) and
connection lines (380ms), plus a `Soft focus` theme that sets all four.
Default stays `legacy`, so an untouched install is unchanged.
The terminal pane is the one surface that cannot blur itself the documented
way, and `blur` takes a deliberate exception to the "never a filter on
.terminal-container" rule. Every alternative was measured against a live
xterm and does not work: a backdrop-filter veil on ::before blurs perfectly
while STATIC, and Chrome silently drops the backdrop the moment ANY
animation runs on that pseudo-element (the veil computes blur(15.3px) while
the text behind it stays razor sharp); driving the radius from rAF buys the
same full-screen blur per frame plus main-thread work. The cost the rule
exists to avoid is inherent to blurring a terminal, so the style buys it
knowingly: opt-in, off by default, one ~520ms run per session open, class
straight back off, will-change still unset. Worst-case price, headless
SwiftShader with no GPU: frame deltas 16.7ms -> 33.3ms for the run, against
16.7ms flat for `fade`. cols x rows measured unchanged at 178x38 before,
during and after, so FitAddon never sees it.
The line entrance animates `filter` too, where each line already carried
its glow. Both kinds now hold it in --line-glow and both keyframes say
`blur(N) var(--line-glow)`, so the function lists match and interpolate
instead of the glow vanishing for the run and popping back (a lineage
line's glow is a different colour, set per element). Its 100% frame omits
`opacity` on purpose so the endpoint comes from the element's own resting
value: 0.9 subagent, 0.72 lineage, 0.95 working.
test/entrance-animations.test.ts is a new static guard over the whole
feature, not just this style: the rule -> keyframes -> theme-option chain a
style silently does nothing without, the terminal's paint-only property
allowlist (the FitAddon rule), the --line-glow contract, and reduced-motion
coverage. Mutation-checked both ways.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
All OFF by default (the `legacy` theme), so an untouched install behaves exactly
as before and every mark/apply hook short-circuits on its first line. Opt in via
App Settings > Appearance > Entrance Animations; per-surface control and a live
preview lab at ?animlab=1.
Surfaces and styles:
- Tabs: slide, pop, crt, unroll, boot, flip. A batch launched together cascades
by a configurable stagger.
- Terminal pane: crt, boot, wipe, slide, fade.
- Agent windows: fly (the pre-existing tab-to-window flight, still the default),
crt, materialize, unfold, beam, pop.
- Connection lines: draw, packet, fade.
Three constraints drove the design:
1. Tabs and connection lines are DESTROYED mid-animation on every re-render:
_fullRenderSessionTabs() replaces the strip's innerHTML and
_updateConnectionLinesImmediate() does `svg.innerHTML = ''`, both of which run
constantly while sessions and agents spawn. Each is tracked by id and
re-applied to the fresh element with a NEGATIVE animation-delay so it resumes
at the same offset instead of restarting or snapping. Verified on the real
path: a forced rebuild mid-draw resumed at -0.243s.
2. Terminal-pane styles animate transform/opacity/clip-path ONLY. xterm's
FitAddon derives rows+cols from getComputedStyle(parent).width/height, the
untransformed layout box, so transforms are invisible to it; animating
width/height/padding would have resized the PTY. Verified by forcing
fitAddon.fit() eight times mid-animation: dimensions held at 178x38.
3. A window entrance that transforms also moves the rect its connection line
aims at (crt drifts it 109px, pop 81px). `beam` animates opacity/filter only
(0px drift) so its line can draw toward a stable target; the others refresh
the lines on animationend.
Also fixes: an agent window spawning hidden (its agent belongs to a background
tab) is display:none, so its animation never runs and animationend never fires,
which left the entrance class and its inline custom property stuck on the window
permanently. Hidden windows now skip the entrance entirely.
Styles persist to their own codeman:*Anim localStorage keys, keeping them
per-device without touching the .strict() SettingsUpdateSchema.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Codeman maintainer