CID format is Adobe's latest published font format. It has the characteristics of easy expansion, high speed, good compatibility, simplicity, flexibility, etc. It has become a hot spot for domestic Chinese font development, and can also provide users with better results and more Font.
CID (character identifier) ​​is a character identification code, which consists of two parts: CIDFont and CMap. CIDFont file is the total character set, including all common characters in a specific language. Sorting these characters, their sequence numbers in the total character set are the CID identifiers (Index) of each character; CMap (Character Map) table That is, a character mapping file can map a character's code to a character's CID ID. The CID font library is designed for the large character set market. The basic process is to first find the CID identification code in the CMap table according to the character encoding, and then find the corresponding font data in the CIDFont file.
Compared with the traditional TrueType font library, the advantages of the CID font library are as follows:
1. Easy expansion: From the foregoing, it is easy to add more character sets and encodings to existing CID fonts. The font developer can create a basic character set before adding more words to meet the needs of different users.
2 speed: In the existing printer on compatible print, CID font speed and OCF font library is equivalent, but in the future through the direct support of CID font Postscript interpreter, speed can be accelerated by 50%, to achieve efficient processing of documents This demand is even more urgent for companies with large business volumes.
3. Compatibility: Since in all CID fonts the glyph description uses the standard Type 1 format, it is compatible with most operating systems, application software, and output devices for cross-platform operations such as Macintosh, Windows, and UNIX , And based on the Internet PDF flow, the compatibility requirements are higher.
4. Simplicity: The CID font format greatly reduces the number of font files, from one hundred files in the OCF font library to one, and the storage capacity is reduced by about 15%. Therefore, the production, installation, and debugging of the font library are relatively easy.
5. High quality: In addition to maintaining the original Type 1 prompt information, it also added black and white control prompts to strengthen the control of Chinese, Japanese, and Korean scripts with complex strokes.
6. Anti-piracy: The CID font is essentially a Postscript program protected by copyright. It is easy to install anti-theft protection on the CID font.
These features of the CID font fulfill many of the requirements of the PDF digital workflow and are highly practical.