46 lines
1.7 KiB
Racket
46 lines
1.7 KiB
Racket
#lang scribble/doc
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@require["common.ss"]
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@defclass/title[pen-list% object% ()]{
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A @scheme[pen-list%] object maintains a list of @scheme[pen%]
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objects to avoid repeatedly creating pen objects. A @scheme[pen%]
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object in a pen list cannot be mutated.
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A global pen list @indexed-scheme[the-pen-list] is created automatically.
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@defconstructor/make[()]{
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Creates an empty pen list.
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}
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@defmethod*[([(find-or-create-pen [color (is-a?/c color%)]
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[width (real-in 0 255)]
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[style (one-of/c 'transparent 'solid 'xor 'hilite
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'dot 'long-dash 'short-dash 'dot-dash
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'xor-dot 'xor-long-dash 'xor-short-dash
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'xor-dot-dash)])
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(is-a?/c pen%)]
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[(find-or-create-pen [color-name string?]
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[width (real-in 0 255)]
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[style (one-of/c 'transparent 'solid 'xor 'hilite
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'dot 'long-dash 'short-dash 'dot-dash
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'xor-dot 'xor-long-dash 'xor-short-dash
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'xor-dot-dash)])
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(or/c (is-a?/c pen%) false/c)])]{
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Finds a pen of the given specification, or creates one and adds it to
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the list. The arguments are the same as for creating a @scheme[pen%]
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instance. When @scheme[color-name] is provided, however, the return
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value is @scheme[#f] when no color matching @scheme[color-name] can be
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found in @scheme[the-color-database].
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}}
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