20 lines
623 B
Racket
20 lines
623 B
Racket
#lang racket/gui
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(require slideshow/pict)
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(define-values (*width* *height*) (values 400 40))
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(define (shades inc)
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(for/list ([scale (in-range 0 (+ 1 inc) inc)])
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(round (* 255 scale))))
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(define (grays increment direction)
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(define colors (shades increment))
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(apply hc-append
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((if (eq? direction 'right) identity reverse)
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(for/list ([c colors])
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(colorize (filled-rectangle
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(/ *width* (length colors)) *height*)
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(make-color c c c))))))
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(vc-append (grays 1/8 'right) (grays 1/16 'left)
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(grays 1/32 'right) (grays 1/64 'left))
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