Canvas encoding

Find it in the repository

Collector source

core/signals/canvas/encoding.ts

Export

measurementModule · Signal object

Field definitions

core/definitions/canvas/encoding.ts

Capture membership

Product capture · common/capture/product.ts

Page registration

app/signals/registry.ts

Field projection

core/results/measurement.ts

Execution contract

Signal

canvas.encoding

Collector

canvas.encoding

API / surface

core/signals/canvas/encoding.ts

Timeout

1750 ms

Companion signals

None

Fixture inputs

Inline owned corpora (listed below)

• core/fixtures/canvas/encoder.ts · sha256:3529c496f13b9befd379b27889dee9118a29774b2dd2360e3d7bb1444b77f10c

[
  {
    "key": "canvas.encoding.responses",
    "inputs": {
      "input": {
        "width": 16,
        "height": 16,
        "colorSpace": "srgb",
        "corpus": "encoder-r1"
      },
      "png": {
        "type": "image/png",
        "quality": null
      },
      "jpeg-default": {
        "type": "image/jpeg",
        "quality": null
      },
      "jpeg-low": {
        "type": "image/jpeg",
        "quality": 0.25
      },
      "jpeg-high": {
        "type": "image/jpeg",
        "quality": 0.75
      },
      "jpeg-invalid-quality": {
        "type": "image/jpeg",
        "quality": 2
      },
      "webp-default": {
        "type": "image/webp",
        "quality": null
      },
      "webp-high": {
        "type": "image/webp",
        "quality": 0.75
      },
      "invalid-format": {
        "type": "image/x-introspection-invalid",
        "quality": null
      }
    },
    "controls": {}
  }
]

One collector runs per invocation. Results and JSON select this signal’s fields; any companions execute in the same collector.

Generated source manifest lists runtime files, fixture URLs and content digests for this build. The Source tab provides a copyable console sample.

Run and edit locally

From the repository root, start the Astro app, then open /signals/canvas.encoding. Edit the collector source and reload the page to load its new build.

pnpm run dev:web

In a browser module served by this repository’s Vite graph:

import { createCollector } from "/core/collect"
import { measurementModule } from "/core/signals/canvas/encoding"

const signal = measurementModule
const collector = createCollector()
const suite = { signals: [signal] }
const result = await collector.collect(suite)

Reuse the collector owner for repeated calls so collection can enforce cleanup. This returns the collector’s raw result; app/signals/projection.ts selects the retained fields shown on this page.

rg -n 'measurementModule' core app tests
pnpm run check
pnpm run test tests/unit/app/focused-projection.test.ts