awaforge

tableLtsh

AGPL-3.0-onlyRelease 2L4

Table LTSH — per-glyph Linear Threshold (OT §6.4.21).

Module tableLtsh | Source packages/front/office/fonts/src/table/ltsh.js | Deps fontErrors, fontReader | Worker-safe yes

For each glyph, the ppem above which the advance width becomes strictly linear (deviation = 0 relative to the upem/1000-scaled value).

Exports

Symbol Type Description
parseLtsh function (bytes) => { version, numGlyphs, yPels: Uint8Array }.
tableLtsh factory Factory { name, dependencies, factory }.

Usage

import fw from '@awacloud/fw';
import { fw_require, modules } from '@awacloud/fonts';

for (const m of [...fw_require, ...modules]) fw.runtime.register(m);
const { parseLtsh } = fw.runtime.resolve('tableLtsh');
const ltsh = parseLtsh(sfnt.tables.LTSH.bytes);
console.log(ltsh.yPels[10]); // ppem threshold for gid 10

Notes

  • yPels is a Uint8Array (independent copy of the source buffer).
  • Throws fonts/ltsh-truncated if the payload is shorter than 4 + numGlyphs.

See also

  • hdmx — companion table