グリッド模写用のグリッドを表示するSVGファイルを生成するRacketスクリプト

grid.rkt

#lang racket/base

(require racket/format)
(require racket/list)

; grid.rkt

(define x-split 4)
(define y-split 4)
(define margin 50)
(define extension 50)
(define x-grid-size 2000)
(define y-grid-size 2000)
(define line-width 2)
(define line-color "red")

;
; svg writer
;

(printf
    "<svg xmlns=~s viewBox=~s>~n"
    "http://www.w3.org/2000/svg"
    (format "0 0 ~a ~a"
        (+ x-grid-size (* 2 (+ margin extension)))
        (+ y-grid-size (* 2 (+ margin extension)))))

(newline)

(define (near x) (~r x #:precision 3))

(for ((i (range (add1 x-split))))
    (define x (near (+ margin extension (/ (* i x-grid-size) x-split))))
    (printf
        "  <line x1=~s y1=~s x2=~s y2=~s stroke=~s stroke-width=~s />~n"
        x
        (near margin)
        x
        (near (+ margin extension y-grid-size extension))
        line-color
        (near line-width)))

(newline)

(for ((i (range (add1 y-split))))
    (define y (near (+ margin extension (/ (* i y-grid-size) y-split))))
    (printf
        "  <line x1=~s y1=~s x2=~s y2=~s stroke=~s stroke-width=~s />~n"
        (near margin)
        y
        (near (+ margin extension x-grid-size extension))
        y
        line-color
        (near line-width)))

(newline)

(printf "</svg>~n")