2016年11月1日火曜日

開発環境

素数夜曲 (吉田 武 (著)、東海大学出版会)の付録D(女王陛下のLISP)、D.6(パスカルの三角形と剰余)、D.6.5(パスカルカラーの世界)を JavaScript で取り組んでみる。

コード(Emacs)

HTML5

<div id="graph0"></div>
<label for="row0">段数: </label>
<input id="row0" type="number" min="0" step="1" value="63">
<label for="m0">除数: </label>
<input id="m0" type="number" min="1" step="1" max="12" value="3">
<label for="r0">点の半径: </label>
<input id="r0" type="number" min="1" step="1" value="4">

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.6/d3.min.js" integrity="sha256-5idA201uSwHAROtCops7codXJ0vja+6wbBrZdQ6ETQc=" crossorigin="anonymous"></script>

<script src="sample8.js"></script>

JavaScript

{
    let div_graph = document.querySelector('#graph0'),
        input_row = document.querySelector('#row0'),
        input_m = document.querySelector('#m0'),
        input_r = document.querySelector('#r0'),
        inputs = [input_row, input_m, input_r],
        width = 600,
        height = 600,
        padding = 20,
        svg,
        colors = ['yellow', 'black', 'orange', 'yelloGreen ', 'green',
                  'lightBlue', 'purple', 'red', 'brown', 'blue', 'pink',
                  'white'];

    let iota = (start, end, step=1) => {
        let result = [];
        
        for (let i = start; i <= end; i += step) {
            result.push(i);
        }
        return result;
    };
    let fact = (n) => {
        let result = 1;
        for (let i = 2; i <= n; i += 1) {
            result *= i;
        }
        return result;
    };
    let bc = (n, r) => {
        return Math.round(fact(n) / (fact(r) * fact(n - r)));
    };
    let row = (n) => {
        return iota(0, n).map((x) => bc(n, x));
    };
    let row_mod = (n, m) => {
        return row(n).map((x) => Math.round(x % m));
    };
    let tri_n = (n) => {
        let y = -n;
        
        return iota(y, n, 2).map((x) => [x, y]);
    };
    let mod_xy = (n, m) => {
        let a = tri_n(n),
            b = row_mod(n, m),
            result = [];

        for (let i = 0; i < a.length; i += 1) {
            let x = a[i].slice();
            x.push(b[i]);
            result.push(x);
        }
        return result;
    };
    let plot_data = (n, m) => {
        return iota(0, n).map((x) => mod_xy(x, m))
            .reduce((x, y) => x.concat(y), []);
    };
    let draw = () => {
        let n = parseInt(input_row.value, 10) - 1,
            m = parseInt(input_m.value, 10),
            r = parseInt(input_r.value, 10),
            // dataset = build(n, m),
            dataset = plot_data(n, m),
            xscale,
            yscale;

        xscale = d3.scaleLinear()
            .domain([-n, n])
            .range([padding, width - padding]);
        yscale = d3.scaleLinear()
            .domain([0, -n])
            .range([padding, height * Math.sqrt(3) / 2 - padding]);

        div_graph.innerHTML = '';
        svg = d3.select('#graph0')
            .append('svg')
            .attr('width', width)
            .attr('height', height);

        svg.selectAll('circle')
            .data(dataset)
            .enter()
            .append('circle')
            .attr('cx', (d) => xscale(d[0]))
            .attr('cy', (d) => yscale(d[1]))
            .attr('r', r)
            .attr('fill', (d) => {
                return colors[d[2]];
            });
    };

    inputs.forEach((input) => input.onchange = draw);
    draw();
}

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