50 lines
1.4 KiB
Scheme
50 lines
1.4 KiB
Scheme
(define plotter
|
|
(lambda (fx res x1 x2 y1 y2)
|
|
(let* ((dx (- x2 x1)) (dy (- y2 y1)) (delta (/ dx res))
|
|
(fstr (format "~a" fx))
|
|
(f (eval (list 'lambda '(x) fx))))
|
|
(letrec
|
|
((scaled
|
|
(lambda (f x y)
|
|
(f
|
|
(* res (/ (- x x1) dx))
|
|
(* res (/ (- y y1) dy)))))
|
|
(scaled-d
|
|
(lambda (f x y xd yd)
|
|
(f
|
|
(+ xd (* res (/ (- x x1) dx)))
|
|
(+ yd (* res (/ (- y y1) dy))))))
|
|
(plotit
|
|
(lambda (x)
|
|
(scaled draw-line x (f x))
|
|
(if (< x x2) (plotit (+ x delta))))))
|
|
(draw-color 0 0 0)
|
|
(draw-font "Helvetica" 12)
|
|
(scaled draw-move 0 (* 1.1 y2)) (draw-string "y")
|
|
(scaled draw-move (* 1.1 x2) 0) (draw-string "x")
|
|
(draw-move
|
|
(- (/ res 2)
|
|
(/ (car (string-size fstr "Helvetica" 12)) 2))
|
|
(+ 30 res))
|
|
(draw-string (format "~a" fstr))
|
|
(scaled draw-move 0 y1)
|
|
(scaled draw-line 0 y2)
|
|
(scaled-d draw-move 0 y2 -5 -7)
|
|
(scaled draw-line 0 y2)
|
|
(scaled-d draw-move 0 y2 +5 -7)
|
|
(scaled draw-line 0 y2)
|
|
(scaled draw-move x1 0)
|
|
(scaled draw-line x2 0)
|
|
(scaled-d draw-move x2 0 -7 -5)
|
|
(scaled draw-line x2 0)
|
|
(scaled-d draw-move x2 0 -7 +5)
|
|
(scaled draw-line x2 0)
|
|
(draw-color 255 0 0)
|
|
(scaled draw-move x1 (f x1))
|
|
(plotit x1)))))
|
|
|
|
(plotter '(* x x x) 70 -5.0 5.0 -50.0 50.0)
|
|
(plotter '(sin x) 50 -5.0 5.0 -1.0 1.0)
|
|
(plotter '(* x (sin x)) 100 -25.0 25.0 -25.0 25.0)
|
|
(plotter '(+ (* x x) (* -5 x) 6) 80 -1.0 5.0 -3.0 10.0)
|