PDFlib 8 Windows COM/.NET Tutorial

5.4.4 Searching for Fonts
Sources of Font Data. As mentioned earlier, fonts can be loaded explicitly with the
load_font( ) function or implicitly by supplying the fontname and encoding options to
various text output functions. You can use a font’s native name or work with arbitrary
custom names which will be used to locate the font data. Custom font names must be
unique within a document. In info_font( ) this font name can be queried with the
apiname key.
Subsequent calls to load_font( ) will return the same font handle if all options are
identical to those provided in the first call to this function (a few options are treated differently;
see PDFlib API Reference for details). Otherwise a new font handle will be created
for the same font name. PDFlib supports the following sources of font data:
> Disk-based or virtual font files
> Fonts pulled from the Windows or Mac operating system (host fonts)
> PDF standard fonts: these are from a small set of Latin and CJK fonts with wellknown
names
> Type 3 fonts which have been defined with begin_font( ) and related functions.
Cookbook A full code sample can be found in the Cookbook topic fonts/font_resources.
Search order for fonts. The font name supplied to PDFlib is a name string. PDFlib uses
the specified font name to search for fonts of various types in the following order. The
search process stops as soon as one of the steps located a usable font:
> The font name matches the name of a standard CJK font and the specified encoding
is the name of a predefined CMap (see Section 6.5.1, »Standard CJK Fonts«, page 172).
> The font name matches the name of a Type 3 font which has previously been created
in the same document with begin_font( ) (see Section 5.1.5, »Type 3 Fonts«, page 119).
> The font name matches the name in a FontOutline resource which connects the font
name with the name of a TrueType or OpenType font file.
> The font name matches the name in a FontAFM or FontPFM resource which connects
the font name with the name of a PostScript Type 1 font metrics file.
> The font name matches the name in a HostFont resource which connects the font
name with the name of a font installed on the system.
> The font name matches the name of a Latin core font (see »Latin core fonts«, page
135).
> The name matches the name of a host font installed on the system (see Section 5.4.5,
»Host Fonts on Windows and Mac OS X«, page 137).
> The font name matches the base name (i.e. without file name suffix) of a font file.
If no font was found, font loading stops with the following error message:
Font file (AFM, PFM, TTF, OTF etc.) or host font not found
Details regarding the resource categories can be found in Section 3.1.3, »Resource Configuration
and File Search«, page 62. The following sections discuss font loading for the
various classes of fonts in more detail.
132 Chapter 5: Font Handling (Edition for COM, .NET, and REALbasic)