This is a webapp for working with web fonts, and contains useful functionality for deploying them to production:
- Subsetting: Reduce the character set of the fonts to only languages used on your website, and remove unnecessary OpenType features, saving space
- Instancing: Convert variable fonts to sets of static fonts.
- Converting: Convert TTF/OTF fonts to WOFF2 (and optionally WOFF, if you need to support older browsers). You can also use this app as a WOFF(2) -> TTF converter if you so desire.
- Packaging: Do all of the above and generate a CSS file containing
@font-facedeclarations for all the fonts. You can then download all the fonts and use them for your site.
Unlike all similar web-based tools that I'm aware of, this runs entirely client-side via WebAssembly. Despite the performance penalty of running in WebAssembly compared to native code, this is actually significantly faster than other web-based tools I've tested, and probably all the Python ones too.
The actual font subsetting/instancing is done via the HarfBuzz library, compiled to WebAssembly.
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Glypht:
- Performs subsetting, instancing, conversion, and packaging.
- Performs conversion in parallel using web workers.
- Is browser-based, but runs client-side--no fonts are ever uploaded to a third-party server.
- Is designed with first-class support for variable fonts. Many similar tools don't support variable fonts at all, and those that do (e.g. pyftsubset) don't support subsetting the variable axes themselves.
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FontSquirrel's webfont generator:
- Performs subsetting, hinting, conversion, feature flattening/freezing, and packaging.
- Seems to perform its own secret-sauce autohinting by default, even if the font already has hinting.
- "Auto-adjusts" vertical metrics by default.
- May also do other processing steps that are geared towards the legacy web and are of dubious merit today.
- Runs server-side, and is extremely slow (10 seconds just to upload small font files, around a minute to process them) 84C0 .
- Doesn't support variable fonts; just returns a .zip containing no font files at all (after the requisite 1-minute wait).
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- Performs character subsetting only; doesn't do any conversion.
- Runs server-side; quite fast, but appears to have a hidden file size limit that it doesn't tell you about, and fails silently if you exceed it.
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- Does both subsetting and conversion, as a command-line tool.
- Written in Python and hence may be tricky to install.
- Unlike Glypht, doesn't support instancing, pinning, or restricting the range of OpenType variation axes (for variable fonts).
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- Command-line tool; shells out to
pyftsubsetfor the subsetting part. - Allows for very precise subsetting by scanning for all characters used in a given file or set of files.
- Command-line tool; shells out to
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- Command-line interface for the same API that Glypht uses internally.
- Supports all the same subsetting operations as Glypht does.
- Performs subsetting only, no conversion.
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- Performs conversion only; no subsetting.
- Doesn't generate CSS.
- Runs client-side, but only uses one thread (Glypht can convert multiple fonts in parallel).
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- Performs packaging of fonts available from Google Fonts, allowing them to be self-hosted.
- Instancing is required; variable fonts will be converted into static fonts, increasing the total download size. This is not Google Fonts' fault, but rather a limitation of google-webfonts-helper itself.
- Doesn't support any non-default OpenType features (like character variants, stylistic sets, tabular figures, small caps, etc), since Google Fonts strips them.
Variable font support is so useful because variable fonts are smaller than static fonts. One variable font in a variety of styles is typically smaller than the equivalent split into several static fonts, and can be served with just one HTTP request.
Take Inter, for example. It's a variable font with a weight that ranges from 100 to 900.
With Glypht's default subsetting settings, the font (in WOFF2 format) is 235KB at this full range of weights.
Let's say you only need certain weights, say, 400 (regular) to 700 (bold). If you export those weights as two separate static fonts with weights 400 and 700, the "regular" weight is 101KB and the "bold" weight is 103KB, for a total of 204KB.
However, Glypht lets you go even further and limit the font's weight range while keeping it a variable font. As far as I know, hb-subset is the only other tool which can do this.
If Inter's weight range is limited to 400-700, with the other settings remaining the same, the font is now 163KB, smaller than both the full variable font and the pair of static fonts! As an added bonus, you get all the weights between 400 and 700 for free.
- Instance different character sets into different font files, using the
@font-facerule'sunicode-rangeproperty - Allow for "freezing" OpenType features (see https://twardoch.github.io/fonttools-opentype-feature-freezer/)
- Autohinting
- This is tricky because we may need different autohinters for CFF/CFF2 and TrueType outlines
- Move the core functionality into a library and expose a CLI for it as well
- Preview the glyphs in a font
- Preview font features (see https://fontdrop.info/)
- Make use of the data in https://github.com/google/fonts/ for font preview text, axis descriptions, etc.
- Support the new incremental font transfer standard
- Probably should wait for it to be actually standardized though
- Use the feature tag info registry more (show explanations of font features)