TrueType fonts are OpenType.

We’ve been serving fonts to iOS for a while now, but they only supported SVG fonts. This change marks an update to (we believe, superior) TrueType fonts.

It wasn’t clear in the post, but we have found the overall performance of TrueType fonts to be superior over SVG. The main factor driving this is that the time to render in the Mobile Safari is significantly less for TrueType files giving an ultimately better experience for your users.

I read that part of the Apple’s reasoning for not originally supporting embedded fonts was the obvious implications of file size for mobile devices. I find this ironic because as a Web Developer, I know that designers want to use the typefaces the choose, and when embedding isn’t an option, I’ve had to degrade to using Cufon or images, both of which are often larger in file size.

Obviously, a TrueType font file is smaller than a SVG font file but only if you do not permforme any king of compression. By using, SVGZ font file (which are SVG file compressed through GZip) or by dealing with Gz/deflate compression over HTTP, SVG compressed files are smaller than TrueType compressed file.

Of course, TrueType file are better rendered even if sometime it’s hard to say. But in a mobile environment, TrueType file remain quite heavy. I’ve made some tests that demonstrate to me that sometimes compressed SVG is better on low bandwidth connexions. I’m not sure there is a strait answer here and anyone should perform it’s one test with it’s own fonts to be sure.