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5 Font Handling5.1 Overview of Fonts and EncodingsFont handling is one of the most complex aspects of document formats. In this sectionwe will summarize PDFlib’s main characteristics with regard to font handling.5.1.1 Supported Font FormatsPDFlib supports a variety of font types. This section summarizes the supported fonttypes and notes some of the most important aspects of these formats.PostScript Type 1 fonts. PostScript fonts can be packaged in various file formats, andare usually accompanied by a separate file containing metrics and other font-related information.PDFlib supports Mac and Windows PostScript fonts, and all common file formatsfor PostScript font outline and metrics data.TrueType fonts. PDFlib supports vector-based TrueType fonts, but not those based onbitmaps. The TrueType font file must be supplied in Windows TTF or TTC format, ormust be installed in the Mac or Windows operating system.OpenType fonts. OpenType is a modern font format which combines PostScript andTrueType technology, and uses a platform-independent file format. There are two flavorsof OpenType fonts, both of which are supported by PDFlib:> OpenType fonts with TrueType outlines (*.ttf) look and feel like usual TrueTypefonts.> OpenType fonts with PostScript outlines (*.otf) contain PostScript data in a True-Type-like file format. This flavor is also called CFF (Compact Font Format).Contrary to PostScript Type 1 fonts, TrueType and OpenType fonts do not require anyadditional metrics file since the metrics information is included in the font file itself.Chinese, Japanese, and Korean (CJK) fonts. In addition to Acrobat’s standard CJK fonts(see Section 5.6, »Chinese, Japanese, and Korean Fonts«, page 116), PDFlib supports customCJK fonts in the TrueType and OpenType formats. Generally these fonts are treatedsimilarly to Western fonts.Type 3 fonts. In addition to PostScript, TrueType, and OpenType fonts, PDFlib alsosupports the concept of user-defined (Type 3) PDF fonts. Unlike the common font formats,user-defined fonts are not fetched from an external source (font file or operatingsystem services), but must be completely defined by the client by means of PDFlib’s nativetext, graphics, and image functions. Type 3 fonts are useful for the following purposes:> bitmap fonts,> custom graphics, such as logos can easily be printed using simple text operators,> Japanese gaiji (user-defined characters) which are not available in any predefinedfont or encoding.5.1 Overview of Fonts and Encodings 95