Calamus (DTP)

Calamus is a RIP itself and handles various, adjustable raster dot sizes at the same time. It handles rasterization information per document, page or even per frame. It also uses a unique, notable method of cutting raster dots, which means that a screen raster can be cropped or clipped at certain borders, given by the document layout elements. Thus, it does not require any external RIP for interpretation, rendering and screening of documents. Using a special module, Calamus supports dot rasterization (using the term Star Screening) which is a frequency modulated method of halftoning (Stochastic screening).

Kerning in Calamus works with sets of left and right bounds measured at different heights for each glyph

Rather than using kerning pairs or relying on simple side-bearing measurements, Calamus’ native fonts encode left and right bounds for each character at eight different latitudes.[3] Unlike the kerning information in other formats, the resulting jigsaw-pieces can be used to fit characters together, even if those characters are from different fonts or if they are set at different sizes.

In contrast, the kerning implementation in OpenType and TrueType only works when adjacent characters are part of the same font, which can result in character collisions or poor kerning in some instances. The alternative is to use optical kerning, where the shapes of the characters are analysed to determine the appropriate distances; Calamus’ approach might be regarded as a simplification of that, working with a low-resolution version of the final character.

• iCalamus
• Atari ST character set

• Official Calamus website
• Official iCalamus website
• Review of Calamus SL2006