svn: r10329
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@ -13,10 +13,8 @@ The teachpack provides two sets of tools. The first allows students to
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create and display a series of animated scenes, i.e., a simulation. The
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second one generalizes the first by adding interactive GUI features.
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@declare-exporting[teachpack/htdp/world #:use-sources (teachpack/htdp/image)]
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@section[#:tag "basics"]{Basics}
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The teachpack assumes working knowledge of the basic image manipulation
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@ -29,10 +27,14 @@ primitives and introduces a special kind of image: a scene.
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The teachpack can display only @tech{Scene}s, which are images whose
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pinholes are at position @scheme[(0,0)].
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@defproc[(empty-scene [width natural-number/c][height natural-number/c]) (unsyntax @tech{Scene})]{Creates a @scheme[width] x @scheme[height] @tech{Scene}.}
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@defproc[(empty-scene [width natural-number/c]
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[height natural-number/c])
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(unsyntax @tech{Scene})]
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{Creates a @scheme[width] x @scheme[height] @tech{Scene}.}
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@defproc[(place-image [img image?] [x number?][y number?][s (unsyntax @tech{Scene})]) (unsyntax @tech{Scene})]{
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Creates a scene by placing @scheme[img] at @scheme[(x,y)] into @scheme[s];
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@defproc[(place-image [img image?] [x number?][y number?]
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[s (unsyntax @tech{Scene})]) (unsyntax @tech{Scene})]
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{Creates a scene by placing @scheme[img] at @scheme[(x,y)] into @scheme[s];
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@scheme[(x,y)] are comp. graph. coordinates, i.e., they count left and
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down from the upper-left corner.}
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@ -151,9 +153,9 @@ A @tech{KeyEvent} represents key board events, e.g., keys pressed or
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whenever the canvas must be redrawn. The canvas is usually re-drawn after a tick event, a keyboard
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event, or a mouse event has occurred. The generated scene is displayed in the world's canvas.}
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@defproc[(is-end-of-world [last-world? (-> (unsyntax @tech{World}) boolean?)]) true]{
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@defproc[(stop-when [last-world? (-> (unsyntax @tech{World}) boolean?)]) true]{
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Tell DrScheme to call @scheme[last-world?] whenever the canvas is
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drawn. If this call produces @scheme[true], the clock is stopped; no
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drawn. If this call produces @scheme[true], the clock is stopped; no more
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tick events, @tech{KeyEvent}s, or @tech{MouseEvent}s are forwarded to
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the respective handlers. As a result, the canvas isn't updated either.}
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