Yesterday, Adobe, in cooperation with Google, announced that the Adobe CFF rasterizer has been contributed FreeType. If you’re a font geek, this is fantastic news. If not, you might be thinking to yourself, “CFF is what again? Why is this important?”.
In a nutshell, modern outline fonts use two formats, TrueType and CFF. A TrueType font has a lot of ‘hinting’ in the font file itself, indicating how best the font should be rendered. CFF font files contain less hinting. They are dependent more on the quality of the rasterizer.
However, because there is less hinting within the file, and due to its efficient file format, CFF fonts are on average about 20-50% smaller than TrueType fonts.
FreeType is an open source library used for font rendering on Android, iOS, Chrome OS, GNU/Linux, and other free Unix operating system derivatives such as FreeBSD and NetBSD. That makes for more than a billion devices running FreeType.
Let’s take a look at how the Adobe CFF rasterizer improves the rendering of CFF fonts. The left column below contains a CFF font rendered with the FreeType hinter. The middle column is rendered with FreeType’s light-auto hinter. And finally, the right column is rendered with the CFF rasterizer that Adobe has contributed to FreeType:
The difference is pretty self-evident.
I don’t think it’s a big leap to understand why it is important to have smaller font files on mobile devices and to have the rendering of those fonts improve dramatically.
More good news for the Web.