This is a format for presenting fonts in PDF files that was initially conceived to store symbols in the Japanese and Chinese languages because it had a 16-bit structure and allowed for more precise adjustment. CID expands the the potential for PostScript by supporting languages that do not have a left-to-right orientation, and by supporting even a vertical mode of orientation.
It is used as a common format for bitmaps in operating systems environments based on the UNIX kernel. It is designed for use in many types of graphics. It can be used for all kinds of data with two-dimensional arrays. It covers the RGB-space and transparency levels.