Pretext: Fast DOM-Free Text Height Measurement

Pretext: a JavaScript/TypeScript library for multiline text height measurement and per-line layout.

Key features:

• Measures text height via canvas glyph widths. No DOM reflow
• Supports RTL scripts, bidirectional text, and emoji out of the box
• Provides line-by-line iterators for canvas, SVG, and WebGL rendering
• Variable-width column flow for float-aware text layout
• TypeScript type definitions included

A great pick if you're building virtualized lists, masonry grids, or any custom text renderer that needs pixel-accurate paragraph heights at scale.

👉 Blog Post

👉 GitHub Repo

👉 Live Demo