Contents
What is a CID font?
CID stands for Character Identifier font, which is a digital font technology primarily used for high-quality print output. A CID font is a format used to encode and display characters in the Adobe PostScript and PDF (Portable Document Format) files.
CID fonts are unique in that they use a different approach to encoding and displaying characters compared to traditional fonts. Instead of representing each character with a specific glyph (visual representation of a character), CID fonts use a character identifier (CID) number to reference a specific glyph in a font’s glyph library.
CID fonts are often used for languages that have a large number of characters, such as CJK (Chinese, Japanese, and Korean) languages. Since these languages have thousands of characters, a traditional font format would require a massive set of glyphs, which would be impractical. CID fonts overcome this limitation by using a smaller set of glyph shapes and assigning a unique CID number to each character.
The CID font architecture
CID fonts are composed of two main components: the CIDFont dictionary and the CIDToGIDMap.
The CIDFont dictionary contains information about the font, such as font name, glyph width, and other font-specific attributes. It also includes a reference to the CIDToGIDMap, which is a mapping table that associates each CID with its corresponding glyph identifier (GID).
The CIDToGIDMap is crucial for rendering text using CID fonts. It maps the CID numbers to the GID numbers, which then point to specific glyphs in the font’s glyph library. This mapping allows software applications to accurately display the correct glyphs for each character based on their CID.
Benefits of using CID fonts
CID fonts offer several benefits, especially for languages with many characters:
1. Compact file size: Since CID fonts use a smaller set of glyph shapes and reference them through CID and GID numbers, the font files tend to be smaller compared to traditional fonts that require a complete set of glyphs for each character.
2. Efficient document representation: CID fonts allow for efficient representation of documents containing a large number of characters. They eliminate redundancy by using a single glyph shape for multiple characters that share a similar structure.
3. Flexibility: CID fonts are highly flexible and can be scaled, rotated, and otherwise modified without losing quality. This is particularly useful for digital and print documents that require various typographic transformations.
4. Support for complex scripts: CID fonts are known for their excellent support of complex scripts, such as Arabic, Hebrew, and Indian languages. They can handle the complex shaping and contextual ligatures required by these scripts with ease.
In summary, CID fonts are a unique digital font technology that enables high-quality print output for languages with a large number of characters. Its character identifier-based approach allows for efficient and compact font files, excellent support for complex scripts, and flexibility in typographic transformations.
Reference Articles
Read also
[Google Chrome] The definitive solution for right-click translations that no longer come up.