TrueType

TrueType is an outline font standard developed by Apple Computer in the late 1980s as a competitor to Adobe's Type 1 fonts. It was designed to offer improved scalability and greater control over font rendering compared to earlier font technologies.

The TrueType format specifies fonts using Bézier curves to define the shape of each character. These curves are then used by the font rasterizer to create the bitmap representation of the character at the desired size and resolution. A key feature of TrueType is its hinting system, which provides instructions on how to adjust the font's shape at small sizes to maintain legibility and prevent distortion. These hints guide the rasterizer in prioritizing certain features, such as stems and serifs, to ensure they are rendered sharply, even at low resolutions.

TrueType was initially included as the standard font format in Apple's Macintosh operating system and was later adopted by Microsoft for Windows. Its cross-platform availability contributed significantly to its widespread acceptance and use. It remains a widely used font format today.

The format is open, meaning that its specification is publicly available, allowing font designers and software developers to create and use TrueType fonts without licensing fees. This openness has fostered a large ecosystem of TrueType fonts, both commercial and freely available. TrueType fonts commonly have the file extension .ttf. OpenType fonts, a later development, often include TrueType outlines and also use the .ttf extension, making the distinction based solely on the extension unreliable. OpenType fonts can also use PostScript outlines and the .otf extension.