2018年9月22日土曜日

学習環境

アニメーションが面白かったので、変化していく様を手動で自分の好みの速度で眺めることが出来るようにしてみた。

コード(Emacs)

HTML5

<div id="graph0"></div>
<pre id="output0"></pre>
<label for="r0">r = </label>
<input id="r0" type="number" min="0" value="2">
<label for="dtheta">dθ = </label>
<input id="dtheta" type="number" min="0" value="0.25">

<br>
<label for="x1">x1 = </label>
<input id="x1" type="number" value="-1.5">
<label for="x2">x2 = </label>
<input id="x2" type="number" value="1.5">
<br>
<label for="y1">y1 = </label>
<input id="y1" type="number" value="-1.5">
<label for="y2">y2 = </label>
<input id="y2" type="number" value="1.5">
<br>
<label for="n0">その</label>
<input id="n0" type="number" step="1" min="1" max="3" value="1">
<br>
<label for="alpha0">α =</label>
<input id="alpha0" type="number" step="15" value="0">

<button id="draw0">draw</button>
<button id="clear0">clear</button>

<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="sample.js"></script>

JavaScript

let div0 = document.querySelector('#graph0'),
    pre0 = document.querySelector('#output0'),
    width = 600,
    height = 600,
    padding = 50,
    btn0 = document.querySelector('#draw0'),
    btn1 = document.querySelector('#clear0'),
    input_r = document.querySelector('#r0'),
    input_dtheta = document.querySelector('#dtheta'),
    input_x1 = document.querySelector('#x1'),
    input_x2 = document.querySelector('#x2'),
    input_y1 = document.querySelector('#y1'),
    input_y2 = document.querySelector('#y2'),
    input_n0 = document.querySelector('#n0'),
    input_alpha = document.querySelector('#alpha0'),
    inputs = [input_r, input_dtheta, input_x1, input_x2, input_y1, input_y2,
              input_n0, input_alpha],
    p = (x) => pre0.textContent += x + '\n',
    range = (start, end, step=1) => {
        let res = [];
        for (let i = start; i < end; i += step) {
            res.push(i);
        }
        return res;
    };

let draw = () => {
    pre0.textContent = '';

    let r = parseFloat(input_r.value),
        d_theta = parseFloat(input_dtheta.value),
        x1 = parseFloat(input_x1.value),
        x2 = parseFloat(input_x2.value),
        y1 = parseFloat(input_y1.value),
        y2 = parseFloat(input_y2.value),
        n0 = parseInt(input_n0.value),
        alpha = parseFloat(input_alpha.value);

    if (r === 0 || x1 > x2 || y1 > y2) {
        return;
    }    

    let points = [],        
        lines = [],
        f = [
            (theta) => [
                Math.cos((2 * theta + alpha) / 180 * Math.PI),
                Math.sin(theta / 180 * Math.PI),
                'red'
            ],
            (theta) => [
                Math.cos((3 * theta + alpha) / 180 * Math.PI),
                Math.sin(2 * theta / 180 * Math.PI),
                'green'
            ],
            (theta) => [
                Math.cos(1.25 * theta / 180 * Math.PI),
                Math.sin((2 * theta + alpha) / 180 * Math.PI),
                'blue'
            ]
        ][n0 - 1];

    for (let theta = 0; theta < 360; theta += d_theta) {
        points.push(f(theta));
    }
    
    let xscale = d3.scaleLinear()
        .domain([x1, x2])
        .range([padding, width - padding]);
    let yscale = d3.scaleLinear()
        .domain([y1, y2])
        .range([height - padding, padding]);

    let xaxis = d3.axisBottom().scale(xscale);
    let yaxis = d3.axisLeft().scale(yscale);
    div0.innerHTML = '';
    let svg = d3.select('#graph0')
        .append('svg')
        .attr('width', width)
        .attr('height', height);

    svg.selectAll('line')
        .data([[x1, 0, x2, 0], [0, y1, 0, y2]].concat(lines))
        .enter()
        .append('line')
        .attr('x1', (d) => xscale(d[0]))
        .attr('y1', (d) => yscale(d[1]))
        .attr('x2', (d) => xscale(d[2]))
        .attr('y2', (d) => yscale(d[3]))
        .attr('stroke', (d) => d[4] || 'black');

    svg.selectAll('circle')
        .data(points)
        .enter()
        .append('circle')
        .attr('cx', (d) => xscale(d[0]))
        .attr('cy', (d) => yscale(d[1]))
        .attr('r', r)
        .attr('fill', (d) => d[2] || 'green');

    svg.append('g')
        .attr('transform', `translate(0, ${height - padding})`)
        .call(xaxis);

    svg.append('g')
        .attr('transform', `translate(${padding}, 0)`)
        .call(yaxis);

    p(f);
};

inputs.forEach((input) => input.onchange = draw);
btn0.onclick = draw;
btn1.onclick = () => pre0.textContent = '';
draw();

注意: ブラウザーが固まる場合が有り。(その場合はコピーしてローカルで試してみてください。)











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