TrueType 上的專利

目前 Apple 在 TrueType 規格上擁有三項專利：

1. US Patent 5159668
2. US Patent 5155805
3. US Patent 5325479

其中除 1. 外（有日本專利）都和亞洲國家無關，主要是美國專利。而且除 3. 外都已經過期了。3. 要 2012 才到期。因此我們私下使用是完全無需理會專利問題的。相關問題請參考：

 http://freetype.sourceforge.net/patents.html

感謝分享，看了才知道說原來已經有兩個過期了。只是沒過期的那個很明顯還是會影響FreeType，當然只跟要商業販賣產品的公司有關了。

Apple 的 truetype bytecode 專利過期了！

Prettier Fonts Coming Your Way

...

For years font rendering in Linux was encumbered or restricted from using the functions of the True Type Bytecode Interpreter because the technology to interpret hinting instructions was patented by Apple. Freetype attempted to mimic these functions so users could enjoy a nice anti-aliased font, and as time progressed fonts became more and more attractive. But generally Linux still did not render fonts as nicely as Windows and Mac systems. Savvy users could enable the Bytecode Interpreter themselves much like those who bravely install the patented codecs required to view certain video formats. Sometimes smaller distributions with little to fear from legal action might have enabled it, but for the most part the larger commercially-backed distributions shipped with the legal Freetype - depriving users of beautifully rendered fonts.

But all that is history. As of May 2010, those patents have expired and as of July 12 with version 2.4.0, Freetype ships with the Bytecode Interpreter enabled. Version 2.4.1 was released July 18 to address a small bug found in 2.4.0. Freetype is released under a BSD-style FreeType License and the GPL.

賀！

(專利頁面上還是寫 May 28,2012 才過期，但我想 FreeType 作者應該不會搞錯吧？)

May 28,2012那個是預估的過期日。