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New Improvements to Dynamic Subsetting «

New Improvements to Dynamic Subsetting


Ryan Arruda in News on May 28, 2015

We’re really excited to announce an update to our Dynamic Subsetting technology that helps power the Web Fonts service.

In a nutshell, instead of serving entire fonts to an end user, our Dynamic Subsetting technology creates custom fonts containing only the characters needed to display the page, thus reducing the file size of the font. As you probably can guess, smaller font sizes generally mean faster loading fonts.

“While our previous subsetting technology made impressive inroads in file size reduction and loading time, our new iteration performs even better”

The newest iteration of our Dynamic Subsetting technology optimizes font delivery even further by subsetting the OpenType tables of a font. This will greatly reduce the size of fonts that contain large GSUB, GPOS and GDEF tables, which store information related to advanced typographic features, as well as shaping and positioning text. Also, after a glyph is removed from a font, we now remap the remaining glyphs, allowing us to drastically reduce the size of “index” based tables. Because of this we’ve seen great performance gains for Asian language fonts that—due to their large character sets—often present prohibitively large file sizes for Web use.

Dynamic Subsetting

While our previous subsetting technology made impressive inroads in file size reduction and loading time, our new iteration performs even better: our internal tests produced, on average, fonts with file sizes five times smaller and download times three times faster compared to our previous subsetter. For Korean fonts the gain is even larger—on average providing results 10 times faster than before. Another important gain our technology has achieved is subsetting support for complex scripts—like Arabic and Indic—in addition to East Asian fonts.

The good news is that these updates are all backwards compatible, meaning if you’re using Dynamic Subsetting today, you won’t need to take extra steps to reap the improved benefits for East Asian fonts. Dynamic Subsetting is also automatically enabled for East Asian fonts when using JavaScript publishing; check out our FAQ if you’d like instructions for enabling subsetting for non-East Asian fonts.

Lastly, to help further boost speed we’ve also added additional servers around the globe, as well as implemented a performance-based load balancer—this means font requests are processed by the server closest to your end viewer.

Keep an eye out as we continue to make improvements to the speed and performance of the Web Fonts service!