Ответ: Spot-функция для Apogee PDF RIP
Вдогон: в PLRM описана базовая идея построения соответствующей процедуры (раздел 7.4.4):
As a cell’s desired gray level varies from black to white, individual pixels
within the cell change from black to white in a well-defined sequence: if a particular
gray level includes certain white pixels, lighter grays will include the same
white pixels and some additional ones as well. The order in which pixels change
from black to white for increasing gray levels is determined by a PostScript procedure
called a spot function, which specifies the order of pixel whitening in an indirect
way that minimizes interactions with the screen frequency and angle.
Consider a halftone cell to have its own coordinate system: the center of the cell is
the origin and the corners are at coordinates ±1.0 horizontally and vertically.
Each pixel in the cell is centered at horizontal and vertical coordinates that both
lie in the range -1.0 to +1.0. For each pixel, the PostScript interpreter pushes the
pixel’s coordinates on the operand stack and calls the spot function procedure.
The procedure must return a single number in the range -1.0 to +1.0 that defines
the pixel’s position in the whitening order.
Дополнение: надеюсь, Вы понимаете, что с PS растрированием (Standard в терминологии Agfa) Вы практически гарантированно "попадаете" на муар?
