chenglou/pretext

Health v2 · maintenance only

Flags: no_releases no_license

Adoption not part of the score

50754 stars · 2754 forks observed · 2026-10-12

What it is AI-extracted, prompt v1, taxonomy v1, 2026-09-21, confidence 0.97

Pretext is a pure JavaScript/TypeScript library that measures and lays out multiline text without touching the DOM. It works with Canvas, SVG and can be used server‑side for fast, accurate text height calculations.

Use cases

• Calculate the height of a paragraph of text without any DOM reads.
• Lay out multiline text manually for custom chat bubbles or masonry cards.
• Virtualize long lists by predicting item heights accurately.
• Create server‑side text layout for PDF or image generation.
• Implement custom line‑wrapping and justification algorithms in the browser.
• Build responsive UI components that need precise text dimensions.

When to choose

• You need fast, deterministic text height calculations without causing layout reflow.
• Your application performs virtual scrolling or occlusion and requires accurate size prediction.
• You want to render text to Canvas, SVG, or off‑screen contexts.
• You are building custom UI layouts (e.g., chat bubbles, masonry grids) that depend on precise line breaks.

When to avoid

• You already rely on native DOM measurement and performance is not a concern.
• You need a full typographic layout engine with advanced hyphenation, ligatures, or PDF typesetting.
• Your project is limited to environments without Canvas or SVG support.

Facets

library · maturity active

parser ui-components frontend web-development browser text-measurement multiline-layout canvas svg dom-free virtualization typescript layout nodejs

Member repositories

For agents

markdown · JSON · MCP: product_card(name="chenglou/pretext")