External screening engines

The Core RIP publishes a screening API that allows you to supply code (screening modules) to apply your own halftoning algorithms. Screening modules convert continuous tone raster data into screened data. Because the screening algorithm programmed in a screening module is specified by code, it can support any type of screening algorithm, including error diffusion, stochastic, non-monotonic, and object type and color dependent algorithms.

The halftoned rasters are generated band by band during the RIPping process. This reduces the memory requirement as a full page of contone raster doesn't need to be stored. It also allows the screening to be parallelized (assuming a suitable screening algorithm in the module), since the rasterizing in the Core RIP is already multithreaded. OTOH, a module can request that the bands are submitted to it in strictly serialized order, should the algorithm require that.

Multiple screening modules can be registered and used on the same page.

Example modules are provided.

For technical information about the API, see Halftone module interface.