This repository includes a Typst layout package and a Crystal harness to produce bit-exact PNG fixtures for MSG_320x240 message-window rendering.

Files

1. Typst package: typst/social-badge/layout.typ
2. Case manifest: testdata/typst/layout_cases.json
3. Crystal runner: scripts/check_typst_layouts.cr
4. Render outputs: testdata/typst/out/*.typ and testdata/typst/out/*.png

Typst package API

Use render-message-window(...) from typst/social-badge/layout.typ.

Parameters:

1. body content block containing Typst-authored message layout.
2. Optional font_id (nsm, ns, ser, atk, ibm).

The package renders only the message window (320x240) with a fixed 8px inset content box (304x224).

Built-in helpers exported by the package:

1. #place(loc)[content] for alignment within the message window content box.
2. #qr("https://...") for real QR symbol rendering (glyph only, no caption text).

#qr(...) is backed by the vendored local tiaoma package at typst/vendor/tiaoma, so Typst fixture rendering does not depend on network package downloads.

Example:

#import "../../../typst/social-badge/layout.typ": render-message-window, place, qr
#render-message-window(font_id: "nsm")[
  #place(bottom + right)[#qr("https://bbb.io/badge")]
]

Running checks

Run comparison against expected hashes:

crystal run scripts/check_typst_layouts.cr

Update expected hashes after intentional layout changes:

crystal run scripts/check_typst_layouts.cr -- --update

Run one case only:

crystal run scripts/check_typst_layouts.cr -- --case qr_only_right

Bit-exact behavior

1. The runner compiles each case with typst compile --format png --ppi 96.
2. It computes SHA-256 for each PNG.
3. It compares each hash to expected_sha256 in the case manifest.
4. In --update mode, it rewrites expected_sha256 values.

If hashes mismatch, the process exits non-zero for CI or local gate checks.