33 lines
983 B
Plaintext
33 lines
983 B
Plaintext
(lib 'plot)
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(define width 600)
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(define height 400)
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(plot-size width height) ;; set image size
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(define (blue x y) (rgb 0.0 0.0 1.0)) ;; a constant function
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(plot-rgb blue 1 1) ;; blue everywhere
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(lib 'types) ;; uint32 and uint8 vector types
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;; bit-map pixel access
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(define bitmap (pixels->uint32-vector)) ;; screen to vector of int32
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→ 240000
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(define (pix-at x y) (vector-ref bitmap (+ x (* y width))))
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(rgb->list (pix-at 100 200)) → (0 0 255 255) ;; rgb blue
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;; writing to bitmap
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(define (set-color-xy x y col) (vector-set! bitmap (+ x (* y width)) col))
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(for* ((x 100)(y 200)) (set-color-xy x y (rgb 1 1 0))) ;; to bitmap
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(vector->pixels bitmap) ;; bitmap to screen
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;; bit-map color components (r g b a) = index (0 1 2 3) access
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(define bitmap (pixels->uint8-clamped-vector)) ;; screen to vector of uint8
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(vector-length bitmap)
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→ 960000
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(define (blue-at-xy x y) (vector-ref bitmap (+ x 3 (* y width)))) ;; 3 = blue component
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(blue-at-xy 100 200)
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→ 255
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