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Variable font inspector
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Lorp Tuned ui modes (colour schemes) and improved how they’re handled
We can now have points displayed as:

* square (uses fill, strokeWidth and stroke)
* circle (uses fill, strokeWidth and stroke)
* triangle (uses fill, strokeWidth and stroke)
* x-shape (uses strokeWidth and stroke)
* +-shape (uses strokeWidth and stroke)

In the uiMode definition object, we use a parent "point" definition, then we can override it in glyphDefault.points and glyphCurrent.points
Latest commit cad51b5 Dec 13, 2019
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Samsa is a web app that visualizes how variable fonts (VF) work. Type designers, font developers, front end developers and others can use Samsa to open VFs, then inspect VF glyph outlines and other data as they explore the VF designspace using sliders and other UI controls.


Samsa uses the Samsa-Core JavaScript library for processing variable fonts. The library implements much of the OpenType 1.8 Variations specification.

Samsa-Core can also output static TrueType (TTF) fonts, and the Samsa web app provides export of static TTFs from any designspace location. (Note: These are not production ready.)

Samsa is written in ES6 JavaScript with no dependencies. It is normally installed on web servers, but can also be run from any folder with no server setup by double-clicking samsa-gui.html.

Also provided are a command-line utility, Samsa-CLI (samsa-cli.js, for execution via Node.js), and a simple browser VF polyfill, Samsa-Polyfill, samsa-polyfill.js. These are both very short scripts that depend on the Samsa-Core library.


  • Samsa is the main web app.
  • Samsa-CLI is a command-line utility for generating static instances from VFs. It is executed using Node.js.
  • Samsa-Core is the JavaScript library that powers Samsa-GUI and Samsa-CLI.
  • Samsa-Polyfill is a demo that uses Samsa-Core to implement a VF polyfill in browsers.

Try Samsa

There are several ways to try Samsa:

  • Visit
  • Download the repository and double-click samsa-gui.html
    • This works fine for drag-drop usage, but does not allow fonts to be loaded from a server.
  • Download the files and install on a web server
    • You can make a symbolic link from index.html to samsa-gui.html or simply rename samsa-gui.html to index.html
    • Edit fonts/_fontlist_.json to make fonts available from the fonts folder on your server.


The Samsa project grew out of:

  • 2013 work on TTJS, a browser-based TTF outline editor in JavaScript
  • 2017 work to write a VF browser polyfill
  • 2017–2018 work to extend Axis-Praxis in order to visualize what happens inside VFs as designspace location changes

An early version of the VF polyfill was demo’d at TYPO Labs 2017 [video]. The visualization project took a separate development path from Axis-Praxis, and an early version of Samsa was demo’d at TGA Raabs 2017 and TYPO Labs 2018.

With support from Google Fonts in 2019, Samsa now has numerous fixes and other improvements including a new UI, and is released under the Apache-2.0 license.

The name Samsa comes from Gregor Samsa, the protagonist of Franz Kafka’s story, The Metamorphosis.


Feedback and contributions (UI ideas, feature ideas, code) are welcome. Please use the GitHub issues system to report bugs and to suggest improvements.

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