opentypejs/opentype.js

TrueType Collection file. Error: Unsupported OpenType signature ttcf

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#379 opened on Apr 24, 2019

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 (4 comments) (0 reactions) (0 assignees)JavaScript (4,170 stars) (512 forks)batch import
enhancementgood first issue

Description

I am trying to open font file with multiple styles inside.

Expected Behavior

font collection file is handled, opentype.js finds multiple fonts.

Current Behavior

image

Possible Solution

I have know idea to be honest :)

Steps to Reproduce (for bugs)

compile multiple ttf fonts into one file using this guide https://graphicdesign.stackexchange.com/a/104892/137343

Context

I want to get supported styles from font file

Your Environment

  • Version used: web preview
  • Font used: roboto from google fonts
  • Browser Name and version: latest stable firefox and chrome
  • Operating System and version (desktop or mobile): mac, ubuntu 19.04
  • Link to your project:

Contributor guide

Tech stack
javascript
Domain
tooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
JavaScriptOpenType font format
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
The issue requests support for TrueType Collection files (.ttc) which begin with the 'ttcf' signature. The library currently expects an OpenType font with a single sfnt version. To implement, one could detect the 'ttcf' signature at the start of the file, then parse the number of fonts and offsets to each font table, and finally load each font similarly to the existing single font parsing. Potential starting points: the parseBuffer or parse function in the source code. Comments on the issue may indicate that maintainers are open to contributions.