typst/typst

Justification for Arabic

Open

#195 opened on Mar 23, 2023

View on GitHub
 (10 comments) (10 reactions) (0 assignees)Rust (53,538 stars) (1,574 forks)batch import
feature requesthelp wantedlayouttext

Description

Justification of Arabic text is very unique. Usually, they do not add whitespace between words. Instead, Arabic text is justified using two ways:

  • Using more "compressed" or "stretchy" variant glyphs. OT have a tag called jalt to provide these alternatives.
  • Stretching the words by inserting Tatweel between letters.

Example of justified Arabic text from ref. Blue shows the swash Kaf, purple is used for the final elongated Alif, orange marks the Returning Yeh (Bari-Ye), and yellow highlights the use of Tatweels inserted. image

Exmaple of Tatweel insertion: image

Ref:

Contributor guide

Tech stack
rust
Domain
backend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
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
Understanding of Arabic typographyFamiliarity with OpenType featuresRust programming knowledge
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
15
Research direction
Investigate the existing text justification implementation in typst's layout engine. Explore OpenType feature handling, particularly the 'jalt' tag and Tatweel insertion. Review linked references for Arabic justification algorithms. Engage with maintainers on issue #195 for guidance on desired approach.
Justification for Arabic · typst/typst#195 | Good First Issue