ac26fe7554
Also, updates some of the mzlib files to point at `racket/*' libraries rather than to `scheme/*' ones.
145 lines
5.3 KiB
Racket
145 lines
5.3 KiB
Racket
#lang scribble/doc
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@(require "common.rkt" scribble/bnf)
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@definterface/title[font-name-directory<%> ()]{
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There is one @racket[font-name-directory<%>] object:
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@racket[the-font-name-directory]. It implements a mapping from font
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specifications (face, family, style, and weight) to information for
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rendering text on a specific device. Programmers rarely need to
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directly invoke methods of @racket[the-font-name-directory]. It is
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used automatically when drawing text to a @racket[dc<%>]
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object. Nevertheless, @racket[the-font-name-directory] is available
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so that programmers can query or modify the mapping manually. A
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programmer may also need to understand how the face-and-family
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mapping works.
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To extract mapping information from @racket[the-font-name-directory],
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first obtain a @defterm{font ID}, which is an index based on a family
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and optional face string. Font IDs are returned by
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@method[font-name-directory<%> find-or-create-font-id] and
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@method[font-name-directory<%> get-font-id] . A Font ID can be
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combined with a weight and style to obtain a specific mapping value
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via @method[font-name-directory<%> get-screen-name] or
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@method[font-name-directory<%> get-post-script-name].
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For a family without a face string, the corresponding font ID has a
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useful built-in mapping for every platform and device. For a family with a
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face string, @racket[the-font-name-directory] interprets the string
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(in a platform-specific way) to generate a mapping for ``screen''
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drawing (to a canvas's @racket[dc<%>], a @racket[bitmap-dc%], or a
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@racket[printer-dc%]). When drawing to a @racket[post-script-dc%]
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object, the face-specific mapping defaults to the family's mapping.
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@defmethod[(find-family-default-font-id [family (one-of/c 'default 'decorative 'roman 'script
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'swiss 'modern 'symbol 'system)])
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exact-integer?]{
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Gets the font ID representing the default font for a family. See
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@racket[font%] for information about font families.
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}
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@defmethod[(find-or-create-font-id [name string?]
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[family (one-of/c 'default 'decorative 'roman 'script
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'swiss 'modern 'symbol 'system)])
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exact-integer?]{
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Gets the face name for a font ID, initializing the mapping for
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the face name if necessary.
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Font ID are useful only as mapping indices for
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@indexed-racket[the-font-name-directory].
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}
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@defmethod[(get-face-name [font-id exact-integer?])
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(or/c string? false/c)]{
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Gets the face name for a font ID. If the font ID corresponds to
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the default font for a particular family, @racket[#f] is returned.
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}
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@defmethod[(get-family [font-id exact-integer?])
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(one-of/c 'default 'decorative 'roman 'script
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'swiss 'modern 'symbol 'system)]{
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Gets the family for a font ID. See
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@racket[font%] for information about font families.
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}
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@defmethod[(get-font-id [name string?]
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[family (one-of/c 'default 'decorative 'roman 'script
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'swiss 'modern 'symbol 'system)])
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exact-integer?]{
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Gets the font ID for a face name paired with a default family. If the
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mapping for the given pair is not already initialized, @racket[0] is
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returned. See also @method[font-name-directory<%>
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find-or-create-font-id].
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Font ID are useful only as mapping indices for
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@indexed-racket[the-font-name-directory].
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}
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@defmethod[(get-post-script-name [font-id exact-integer?]
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[weight (one-of/c 'normal 'bold 'light)]
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[style (one-of/c 'normal 'italic 'slant)])
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(or/c string? false/c)]{
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Gets a PostScript font name for a font ID, weight, and style
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combination.
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See @racket[font%] for information about @racket[weight] and
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@racket[style].
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}
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@defmethod[(get-screen-name [font-id exact-integer?]
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[weight (one-of/c 'normal 'bold 'light)]
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[style (one-of/c 'normal 'italic 'slant)])
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(or/c string? false/c)]{
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Gets a platform-dependent screen font name (used for drawing to a
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canvas's @racket[dc<%>], a @racket[bitmap-dc%], or a
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@racket[printer-dc%]) for a font ID, weight, and style combination.
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See @racket[font%] for information about @racket[weight] and
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@racket[style].
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}
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@defmethod[(set-post-script-name [font-id exact-integer?]
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[weight (one-of/c 'normal 'bold 'light)]
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[style (one-of/c 'normal 'italic 'slant)]
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[name string?])
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void?]{
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Sets a PostScript font name for a font ID, weight, and style
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combination. See also @method[font-name-directory<%>
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get-post-script-name].
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See @racket[font%] for information about @racket[weight] and @racket[style].
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}
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@defmethod[(set-screen-name [font-id exact-integer?]
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[weight (one-of/c 'normal 'bold 'light)]
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[style (one-of/c 'normal 'italic 'slant)]
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[name string?])
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void?]{
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Sets a platform-dependent screen font name (used for drawing to a
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canvas's @racket[dc<%>], a @racket[bitmap-dc%], or a
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@racket[printer-dc%]) for a font ID, weight, and style combination.
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See @racket[font%] for information about @racket[weight] and
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@racket[style].
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}}
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