CSS OpenType Font Feature Control

I have been working on adding OpenType font feature control to Gecko. An experimental implementation is currently available for Mac OS X and Windows. To enable OpenType feature support in this version, ensure that the gfx.text_layout.harfbuzz preference to true in about:config; restart the browser after changing this setting.

WARNING: This is NOT A FINAL OR PRE-RELEASE VERSION. This program is provided without any guarantees of stability, so please use it at your own risk. It is recommended that you back up your profile regularly, as there may be bugs that corrupt your data. If that sounds scary, you'd probably be better off waiting until font feature support is part of a shipping release.

Several pages are available here that show examples of how CSS control of font features might be used to enhance web pages:

• Recipes showing the use of OpenType fractions
• Tabular data showing options for numeral form and spacing
• MEgalopolis, a bold display font with numerous quirky features
• Turkish, showing language-specific OpenType behavior

John Daggett has also posted some examples using font features:

• Simple display text example using MEgalopolis Extra
• Tabular data with and without numeral-spacing features
• Another recipe example using OpenType fractions
• Historical text with appropriate "period" rendering

There is also an OpenType Feature Playground page where you can experiment further with features, using whatever OpenType fonts you may have available.