:.· The font engine

To display a glyph, meaning to rasterize it for an output device, several steps are necessary.

1. The 'master outline' description (fig. 1-1) of the glyph is scaled to the designated size (fig. 1-2)


2. The scaled outline (fig. 1-2) is placed on the coordinate system with its instruction set taking the resolution of the output device into consideration. (fig. 1-3).


3. The 'scan converter' then converts the so-called 'grid-fitted outline' to a bitmap appropriate for the output device (fig. 1-4).


Resolution problems may occur during rasterization. If the output device's resolution is too low, such as in the case of a monitor, there are not enough pixels available to correctly display a character, or not all details of a small font can be displayed because not all pixels can be appropriately set. For this reason TrueType fonts are supplied with 'instruction' which are basically programs nested within the font itself. They determine how to handle glyphs or the whole font in critical situations. This is also called 'hinting'. The goal here is to provide the best possible output quality at all times.