There is one
font-name-directory<%> object:
the-font-name-directory. It implements a mapping from font
specifications (face, family, style, and weight) to information for
rendering text on a specific device. Programmers rarely need to
directly invoke methods of
the-font-name-directory. It is
used automatically when drawing text to a
dc<%>
object. Nevertheless,
the-font-name-directory is available
so that programmers can query or modify the mapping manually. A
programmer may also need to understand how the face-and-family
mapping works.
To extract mapping information from the-font-name-directory,
first obtain a font ID, which is an index based on a family
and optional face string. Font IDs are returned by
find-or-create-font-id and
get-font-id . A Font ID can be
combined with a weight and style to obtain a specific mapping value
via get-screen-name or
get-post-script-name.
For a family without a face string, the corresponding font ID has a
useful built-in mapping for every platform and device. For a family with a
face string, the-font-name-directory interprets the string
(in a platform-specific way) to generate a mapping for
drawing (to a canvas’s dc<%>, a bitmap-dc%, or a
printer-dc%).
Currently, on all platforms, a face string is interpreted as a
Pango font description when it
contains a comma, otherwise it is treated as a family name. A
face can thus be just a family name such as "Helvetica", a family
followed by a comma and font modifiers as in "Helvetica, Bold", or a sequence of comma-separated
familie names followed by space-separated font options as an
"Helvetica, Arial, bold italic". Any size in a font
description is overridden by a given font%’s size. Any
(slant) style or weight options in a font description are overridden
by a non-'normal value for a given font%’s style or
weight, respectively.
Gets the font ID representing the default font for a family. See
font% for information about font families.
Gets the face name for a font ID, initializing the mapping for
the face name if necessary.
Font ID are useful only as mapping indices for
the-font-name-directory.
Gets the face name for a font ID. If the font ID corresponds to
the default font for a particular family, #f is returned.
Gets the family for a font ID. See
font% for information about font families.
Gets the font ID for a face name paired with a default family. If the
mapping for the given pair is not already initialized,
0 is
returned. See also
find-or-create-font-id.
Font ID are useful only as mapping indices for
the-font-name-directory.
Gets a PostScript font description for a font ID, weight, and style
combination.
See font% for information about weight and
style.
Gets a platform-dependent screen font description (used for drawing to a
canvas’s
dc<%>, a
bitmap-dc%, or a
printer-dc%) for a font ID, weight, and style combination.
See font% for information about weight and
style.
Sets a PostScript font description for a font ID, weight, and style
combination. See also
get-post-script-name.
See font% for information about weight and style.
Sets a platform-dependent screen font description (used for drawing to a
canvas’s
dc<%>, a
bitmap-dc%, or a
printer-dc%) for a font ID, weight, and style combination.
See
font% for information about
weight and
style.