d61eb53686
Started as fixing misindented definitions, then more indentations, then a bunch of similar things (square brackets, huge spaces at end-of-lines, etc).
93 lines
3.1 KiB
Racket
93 lines
3.1 KiB
Racket
#lang scribble/doc
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@(require scribble/manual "shared.rkt"
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(for-label racket teachpack/htdp/gui))
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@teachpack["gui"]{Simple Graphical User Interfaces}
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@;declare-exporting[teachpack/htdp/gui]
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@defmodule[#:require-form beginner-require htdp/gui]
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The teachpack provides functions for creating and manipulating graphical
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user interfaces. We recommend using @racketmodname[2htdp/universe] instead.
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@deftech{Window} A @tech{Window} is a data representation of a visible
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window on your computer screen.
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@deftech{GUI-ITEM} A @tech{GUI-Item} is a data representation of an active
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component of a window on your computer screen.
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@defproc[(create-window [g (listof (listof (unsyntax @tech{GUI-ITEM})))]) Window]{
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Creates a window from the ``matrix'' of gui items @racket[g].}
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@defproc[(window? [x any/c]) boolean?]{Is the given value a window?}
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@defproc[(show-window [w Window]) true]{Shows @racket[w].}
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@defproc[(hide-window [w window]) true]{Hides @racket[w].}
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@defproc[(make-button [label string>][callback (-> event% boolean)]) (unsyntax @tech{GUI-ITEM})]{Creates a
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button with @racket[label] and @racket[callback] function. The latter
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receives an argument that it may safely ignore.}
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@defproc[(make-message [msg string?]) (unsyntax @tech{GUI-ITEM})]{Creates a message item from @racket[msg].}
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@defproc[(draw-message [g (unsyntax @tech{GUI-ITEM})][m string?]) true]{Displays @racket[m]
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in message item @racket[g] and erases the current message.}
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@defproc[(make-text [txt string?]) (unsyntax @tech{GUI-ITEM})]{Creates an text editor (with
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label @racket[txt]) that allows users to enter text.}
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@defproc[(text-contents [g (unsyntax @tech{GUI-ITEM})]) string?]{
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Determines the current contents of a text @tech{GUI-ITEM}.}
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@defproc[(make-choice [choices (listof string?)]) (unsyntax @tech{GUI-ITEM})]{
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Creates a choice menu from @racket[choices] that permits users to choose
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from some alternatives.}
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@defproc[(choice-index [g (unsyntax @tech{GUI-ITEM})]) natural-number/c]{Determines the
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choice that is currently selected in a choice @tech{GUI-ITEM}; the result
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is the 0-based index in the choice menu}
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Example 1:
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@(begin
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#reader scribble/comment-reader
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(racketblock
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> (define w
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(create-window
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(list (list (make-button "QUIT" (lambda (e) (hide-window w)))))))
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;; A button appears on the screen.
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;; Click on the button and it will disappear.
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> (show-window w)
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;; The window disappears.
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))
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Example 2:
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@(begin
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#reader scribble/comment-reader
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(racketblock
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;; text1 : GUI-ITEM
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(define text1
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(make-text "Please enter your name"))
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;; msg1 : GUI-ITEM
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(define msg1
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(make-message (string-append "Hello, World" (make-string 33 #\SPACE))))
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;; Event -> true
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;; draws the current contents of text1 into msg1, prepended with "Hello, "
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(define (respond e)
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(draw-message msg1 (string-append "Hello, " (text-contents text1))))
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;; set up window with three "lines":
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;; a text field, a message, and two buttons
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;; fill in text and click OKAY
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(define w
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(create-window
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(list
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(list text1)
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(list msg1)
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(list (make-button "OKAY" respond)
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(make-button "QUIT" (lambda (e) (hide-window w)))))))
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))
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