Bulletproof Font Tester is a font proofing app that loads user-selected local font files and detects their OpenType features and variation axes. Everything is processed locally in the browser, using OpenType.js.
Available formatting options:
- Changing font size, line height, text alignment, text case transform, text and background colors.
- Toggling OpenType features on and off.
- Choosing localization language from the list of languages built into the font.
- Manipulating OpenType Variation axes.
A set of multilingual texts is collected in a separate project Language-Data. It includes a few kinds of texts:
- ordinary sentences,
- pangrams,
- lettering samples — defined as sets of A-Z words preferably repeating the initial letter within),
- gotchas — edge cases characteristic to the given language, things to look out for when desigining a typeface.
The selection of languages and texts is arbitrary and limited, but contributions are welcome. Currently the focus is on languages written with Latin and Cyrillic.
The app is equipped with a kerning string generator, along with a couple of predefined kerning patterns. See kerning generator help.
Any open text sample can be edited. In the editor tab some more options are available: setting bold and italic (with separately selectable fonts), as well as taking snapshots of the settings and using them as animation keyframes — can be useful for recording gifs or videos, or toggling multiple features on and off more quickly. See animation editor help.
Last tested in Node.JS v12.22.12.