## What
Exposes the `pretext` text-measurement API on `window.__hyperframes`, so the API our agent-facing docs already describe actually exists.
Adds `pretext.prepare`, `.layout`, `.prepareWithSegments`, `.measureLineStats`, `.measureNaturalWidth`.
## Why
`skills/hyperframes-core/references/determinism-rules.md` is required reading for any agent authoring a composition. Line 59 tells them to call `window.__hyperframes.pretext.prepare(text, font)` then `pretext.layout(prepared, maxWidth, lineHeight)` for text measurement without a DOM reflow.
That object did not exist. The runtime exposed exactly `fitTextFontSize` and `getVariables`. Any composition following the documented recipe threw at runtime.
Deleting the doc line was the smaller change, but reflow-free measurement is genuinely the right tool for sizing text per frame, and `fitTextFontSize` is already built on it. Making the docs true is the better fix.
## How
- New `packages/core/src/text/pretext.ts` assembles the exposed surface in one place, with the include/exclude rationale next to it.
- `entry.ts` attaches it alongside the existing helpers. Sub-compositions inherit it for free: the scoping shim builds its scoped variant with `Object.assign({}, base, { getVariables })`, so anything added to the base object is carried through.
Two deliberate decisions:
**Wider than the doc named.** `layout()` returns only `{ lineCount, height }`. The doc's own "shrinkwrap containers" use case needs a width, which is impossible with just `prepare` + `layout`. `measureNaturalWidth` and `measureLineStats` make that claim achievable; `prepareWithSegments` is their required input.
**`clearCache` and `setLocale` withheld.** Both mutate state shared across compositions. Exposing them would let one composition change how a later one measures, making a render depend on what ran before it.
**Doc correction.** The reference called this "pure arithmetic, ~0.0002 ms per call". Not quite: `prepare` measures fonts through a canvas and throws outside a browser. Only the steps after a prepared string are arithmetic. Reworded, and documented the width helpers and the omissions.
## Trade-off
The runtime bundle grows **4,903 bytes (+1.30%)**, from 377,865 to 382,768. That ships inline in every composition. Measured by building the artifact with and without the change.
## Test plan
- [x] Unit tests added/updated
- [x] Manual testing performed
- [x] Documentation updated (if applicable)
`packages/core/src/text/pretext.test.ts` guards the shape of the published surface: the two documented names exist, the width helpers exist, and the two stateful functions are absent. Behaviour is deliberately not asserted there. `prepare` needs a canvas, and mocking it (as `fitTextFontSize.test.ts` must) would assert nothing real.
Real behaviour was verified by rendering a composition that calls the documented API:
```
lines=2 height=216 naturalWidth=1785
```
Self-consistent: natural width 1785 exceeds the 1600 container so it wraps to 2 lines, and 2 x 108 line-height is exactly the reported 216. The frame was inspected visually.
Also run:
- `packages/core` full suite from the package root: **903 passed, 46 files**
- `tsc --noEmit` and `tsc --noEmit -p tsconfig.runtime.json`: clean
- `oxlint` / `oxfmt`: clean
## Follow-ups (not in this PR)
An audit of the wider attribute surface found several more doc/runtime mismatches, including `data-gpu-mode` documented as an HTML attribute when it is a config field, and `data-no-timeline` being real, load-bearing, and absent from the table agents read. Those are separate changes.
The color-grading engine hides its source element with inline
'opacity: 0 !important', so any code that later reads or re-captures the
element's opacity sees the hide instead of the authored value. Stamp the
authored inline opacity on every [data-color-grading] element at document
parse time (MutationObserver installed at runtime-bundle eval, before any
composition script runs) and prefer the stamp when hiding/restoring.
Also re-sync the grading canvas when the source's inline geometry mutates
(rAF-throttled style observer): a studio drag moves the source via its
transform, which fires no media event, so the visible canvas froze in
place until the next seek.
Adds the parametrized-render primitive from hf#592 by reusing the existing
data-composition-variables schema as the source of declared defaults.
- Runtime helper window.__hyperframes.getVariables() (also exported from
@hyperframes/core) reads data-composition-variables defaults from the
document root and merges window.__hfVariables (CLI override) on top.
Returns Partial<T> for typed access; supports a generic for editor
ergonomics. Same code path runs in dev preview and at render time.
- CLI render --variables '<json>' / --variables-file <path> populates the
override. Mutually exclusive; fail-fast on conflicting flags, missing
file, unparseable JSON, or non-object payloads. parseVariablesArg is
exported as a pure function so validation paths stay unit-testable.
- Engine injects window.__hfVariables via evaluateOnNewDocument before
any page script runs, so the helper sees the merged values on its
first call. Empty payloads are skipped to avoid pointless init scripts.
- Producer threads variables through RenderConfig and into the engine's
CaptureOptions; Docker mode forwards --variables to the in-container
CLI invocation via dockerRunArgs.
Composition authors declare variables once on the root <html> element:
<html data-composition-variables='[
{"id":"title","type":"string","label":"Title","default":"Hello"}
]'>
and read them in any composition script:
const { title } = window.__hyperframes.getVariables();
A render with `--variables '{"title":"Q4 Report"}'` overrides the default
without modifying the composition source. Missing keys fall through to
the declared defaults, so dev preview and CLI renders without --variables
behave identically.
This is PR 1 of a 4-PR stack. Sub-comp per-instance scoping (carrying
host data-variable-values through the inlined sub-comp's getVariables()
call) lands in PR 2; schema validation and lint in PR 3; skill / scaffold
distribution in PR 4.
Tests: 9 new unit tests for getVariables() (jsdom), 11 new CLI tests
covering parseVariablesArg validation paths and Docker passthrough,
2 new dockerRunArgs assertions for the --variables flag. All existing
tests green (core 611, cli 208, engine 519).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Add @chenglou/pretext dependency and fitTextFontSize() utility that uses
canvas measureText to compute the largest font size that fits text within
a given width. Replaces character-count heuristics with actual font-aware
measurement.
- New fitTextFontSize() in @hyperframes/core/text, exposed on window.__hyperframes
- Generalized for all text elements (captions, titles, etc.), not just captions
- Unit tests (mocked pretext) + browser integration test (real Chromium canvas)
- Updated captions skill docs with usage, exit guarantee, and self-lint patterns
Co-authored-by: James <james.russo@heygen.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* feat: initial code port from hyperframes-internal
Port all OSS-ready packages from the internal monorepo:
- @hyperframes/core — shared types, HTML generation, GSAP utilities, runtime
- @hyperframes/cli — CLI for creating, previewing, and rendering compositions
- @hyperframes/engine — framework-agnostic rendering engine (BeginFrame + FFmpeg)
- @hyperframes/producer — video rendering pipeline (Puppeteer + FFmpeg)
- @hyperframes/ui-player — browser-based video player component
- @hyperframes/studio — composition editor (React frontend + Hono backend)
Includes regression test suite with Docker-based test harness.
All HeyGen-internal references, deployment infrastructure, and
proprietary assets have been removed. Package names migrated
from @app/* to @hyperframes/*.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix: scrub internal codenames and stale references from OSS port
- Replace static.heygen.ai runtime URLs in test fixtures
- Remove internal CDN publish script (publish-hyperframe-runtime.ts)
- Replace sandbox-studio, sandbox-interceptor, __magicEditRuntime
with neutral names (studio, hyperframe-runtime, __hyperframeRuntime)
- Fix stale Vault API / localhost references in docs
- Remove broken deprecated_studio link
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix: remove remaining internal codenames and stale references
- Delete stale producer README.md and PIPELINE.md (referenced nonexistent files)
- Replace "Cerberus" codename with "HyperFrames" in test design reviews
- Replace magic-edit postMessage identifiers with hf-preview/hf-parent
- Rename debug-magic-edit-timeline.ts to debug-timeline.ts
- Replace "Motion Cut" with "HyperFrames" in Timeline comments
- Fix studio/CLI references to nonexistent archive package
(use local data/projects/ dir, stub render proxy)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Miguel Ángel