36 lines
No EOL
1.1 KiB
Scheme
36 lines
No EOL
1.1 KiB
Scheme
#lang sicp
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(#%require sicp-pict)
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; inappropriate for the way racket implemented these vectors
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;(define (make-vect x y) (cons x y))
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;(define (xcor-vect v) (car v))
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;(define (ycor-vect v) (cdr v))
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(define (xcor-vect v) (vector-xcor v))
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(define (ycor-vect v) (vector-ycor v))
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(define (add-vect u v)
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(make-vect (+ (xcor-vect u) (xcor-vect v))
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(+ (ycor-vect u) (ycor-vect v))))
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(define (sub-vect u v)
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(make-vect (- (xcor-vect u) (xcor-vect v))
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(- (ycor-vect u) (ycor-vect v))))
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(define (scale-vect s v)
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(make-vect (* s (xcor-vect v))
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(* s (ycor-vect v))))
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(define (transform-painter painter origin corner1 corner2)
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(lambda (frame)
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(let ((m (frame-coord-map frame)))
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(let ((new-origin (m origin)))
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(painter (make-frame
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new-origin
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(sub-vect (m corner1) new-origin)
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(sub-vect (m corner2) new-origin)))))))
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(define (flip-horiz painter)
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(transform-painter painter
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(make-vect 1.0 0.0)
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(make-vect 0.0 0.0)
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(make-vect 1.0 1.0))) |