TrueType

Once Apple developed TrueType technology, the company included it in Mac OS System 7 and later and released an add-on package for System 6 to allow use of TrueType fonts. Although TrueType is still fully supported, Mac OS X also has native support for Adobe's Type 1 and Microsoft and Adobe's OpenType formats.

Microsoft has aggressively pushed TrueType into the Windows operating system and includes a fairly useful library of TT fonts with their systems. In addition, they have recently added a number of new font smoothing technologies, including ClearType which can significantly improve readability on LCD based displays. Like Apple, Microsoft has in recent years added Adobe-provided support for Type 1 and OpenType to their operating system, with Windows 2000 and XP.

The characters (or glyphs) in TrueType fonts are made of straight line segments and other quadratic Bézier curves. The standard includes a virtual machine that executes programs inside the font, processing the "hints" of the glyphs (that is, modifying them slightly so that the outline rasterizer produces fewer artifacts when drawing a glyph at a low resolution).

The FreeType project attempts to create an independent implementation of the TrueType standard (as well as other font standards). It ran into legal problems because parts of the TrueType hinting virtual machine were patented by Apple, a fact not mentioned in the TrueType standards. (Patent holders who contribute to standards not published by a major standards body such as ISO are not required to disclose the scope of their patents.) More recent FreeType releases include an automatic hinter that analyzes glyph shapes and corrects them, thus avoiding the patented technology.

Related articles

• Typography
• Typeface

External Links

• The TrueType Specification: http://www.truetype.demon.co.uk/ttspec.htm
• The FreeType project: http://www.freetype.org/