ttf-spacing

*.ttf files parser. Returns json with decoded subset of TTF tables or mapping unicode char to its spacing information.

Useful for calculating spacing of letters for text rendering. See index.html for example.

Parsed ttf file additionally contains glyphIndexMap object, which is dictionary mapping utf-8 char to glyphIndex which is used in other tables such as loca or hmtx.

Usage

yarn parse spacing Inter-Regular.ttf spacing.json
yarn parse ttf Inter-Regular.ttf font.json

Install

Clone the repository. Sorry, no npm package for now.

Docs

Library handles following tables:

• tables
• head
• name
• cmap
• maxp
• loca
• hhea
• hmtx
• glyf

For exact types, consult types.ts.

Shape of glyph spacing information is as follows:

export type Glyph = {
  x: number;
  y: number;
  width: number;
  height: number;
  lsb: number;
  rsb: number;
};

Where lsb is left side bearing, as found in hmtx table, while rsb is right side bearing, calculated with following formula:

const rsb = hmtx.advanceWidth - hmtx.leftSideBearing - (glyf.xMax - glyf.xMin);