* feat(sdk): expose a paint query for transparent-composition hit-testing
A host layering a transparent composition over other content has to know
whether a point carries ink before it decides to swallow a click. The adapter
only answered "what element is here", so AI Studio wrote its own answer and
could not reach the per-pixel alpha the adapter already samples for <img>.
Add PreviewAdapter.paintsAt, plus the pieces it is built from on a new
./adapters/iframe subpath so a host with different hit-test policy can compose
its own walk.
The walk is geometric rather than elementsFromPoint-based: that stack omits
pointer-events:none nodes, and a decorative overlay carrying it still paints,
so a z-stack query would report no ink over visible artwork — the direction
that makes a composition vanish from under the cursor.
fullBleedFraction is an option rather than a constant because "a layer covering
the whole frame is background, not artwork" is host policy, not a fact about
the composition.
* fix(sdk): scope the full-bleed frame to the root under the point
compositionFrameArea took the smallest [data-composition-id] in the whole
document, so an unrelated sub-composition sized the reference frame for points
nowhere near it: a 300x300 badge in a corner made every mid-size painter in a
1920x1080 outer frame read as full-bleed, and the composition went
click-through under artwork the user can plainly see. That is the direction the
fail-safe exists to avoid, and the docs already described the intended
behaviour — the innermost root CONTAINING the point.
Also read the alpha channel instead of matching known transparent spellings.
Only the `transparent` keyword computes to rgba(0, 0, 0, 0); a faded-out white
stays rgba(255, 255, 255, 0), which the set counted as painted. That erred
toward absorbing clicks rather than losing them, so it was a false positive
rather than a hazard, but it is wrong.
Both are pinned by tests that fail when the fix is reverted.
* fix(sdk): stop the paint query answering "no ink" over visible artwork
Four cases where the walk landed on the wrong side of its own fail-safe.
The full-bleed veto tested the winner's border-box area even when the alpha
sampler had just read an opaque pixel there, so a full-frame transparent PNG or
SVG overlay — the case this feature exists for — reported background over
visibly opaque artwork, with no fullBleedFraction that worked. Ink now carries
how it was established, and a measured pixel is never vetoed. An image whose
pixels could NOT be read stays inferred, so a tainted CDN overlay still yields
to the veto rather than absorbing every click.
Composition roots were excluded from candidacy outright, so a root carrying a
background answered false even at fraction 0, where the docs promise every
painting box counts. Roots are candidates now; the veto discounts them without
a special case, since a root's box is the frame.
An <img> with a clear pixel early-returned past its own background, padding
plate and border, which any other element would have counted.
A same-origin iframe mid-navigation exposes a readable but empty document, so
the !doc guard never fired and a loading composition answered a confident
"no ink" — the exact failure the null convention exists to prevent.
Also: the sort comparator's epsilon tie was intransitive, leaving the
smallest-first guarantee (and the lazy single-sample property that rides on it)
engine-dependent; the guide's pass-through recipe called a function that does
not exist and hand-waved the coordinate mapping that makes it correct; and the
reference now states the under-counts alongside the over-counts, the walk's
blindness to runtime-mounted content, and compositionPaintsAt's preconditions.
Each fix is pinned by a test that fails when the fix is reverted.
* refactor(sdk)!: invert the paint query to isProvablyEmptyAt
paintsAt handed callers three falsy bottom values with opposite safe readings:
false meant "no ink, pass the click through", null meant "not knowable, treat as
painted", and undefined from an adapter without the method also meant painted.
The idiomatic `if (!preview.paintsAt?.(x, y)) passThrough()` therefore did the
dangerous thing for two of the three, and the convention needed defending in the
interface docstring, the reference and the guide — plus a dedicated comment and
a pinning test on the headless adapter to stop null regressing to false.
Inverting the polarity collapses the tri-state to a plain boolean and makes the
safe reading structural: true only when the composition was readable and nothing
painted there, so ink, an unreadable or still-loading document, and a missing
implementation all land on "keep the composition clickable". The prose stays as
rationale, but nothing depends on a reader remembering it.
PaintsAtOptions becomes PaintQueryOptions, since it now describes the walk that
both the adapter method and the exported compositionPaintsAt share rather than
one method's arguments. compositionPaintsAt keeps its ink-positive name: it
answers the other question, and its docstring points callers who need the
fail-safe contract at the adapter.
Nothing is released yet, so no consumer is on the old name.
- edit-operations: dispatch() does not consult can() (session.ts:608 -> applyOp
with no validation; a no-timeline addGsapTween/addLabel is a no-op but a missing
target still writes via selector fallback). Use Rames's wording: call can() first
and skip on failure — no false 'applies nothing' guarantee.
- timing-and-animation: the second E_NO_GSAP_TIMELINE site — gated setGsapTween on
an error it cannot return and called shipped parser code 'a later phase'. Rewrote
to gate addGsapTween (which can return it); dropped the stale can() comment in
types.ts:595.
- html-schema: data-playback-start is read by runtime, Studio and CLI (Studio also
writes it, timelineEditingHelpers.ts); only the compile path is media-start only.
Document the layered precedence instead of calling it runtime-only.
Round-2 findings from Magi (#2/#3/#4) and Rames.
A `<br>` is a void element but `resolveSingleChildTextTarget` treated a lone
`<br>` child as the element's text target. So `getOwnText(<h1>A<br>B</h1>)`
read the `<br>`'s (empty) textContent → `text: null`, which consumers surface
as "not editable", and `setOwnText` wrote into the `<br>`, corrupting it
(serialized as invalid `</br>`).
Exclude void elements from the single-child text target; read `<br>` as "\n";
and rebuild the text/`<br>` run from the newline-separated value on write,
reusing existing `<br>` nodes so their identity (data-hf-id) survives an
in-place edit.
Vance Ingalls