平成26年度(2014) 第3回試験 問18 | ウェブデザイン技能検定 ２級

var count = 100;
var nX = 100;
var nY = 100;
start(170, 100);
for (var i = 1; i <= count; i++) {
    var radians = 2 * i * Math.PI / count;
    drawLine(nX + 50 * Math.cos(radians) * 1.4, nY + 50 * Math.sin(radians));
}

var x1 = 0;
var y1 = 0;
function start(x, y) {
    x1 = x;
    y1 = y;
}
function drawLine(x2, y2) {
    var canvas = document.getElementById("myCanvas");
    var ctx = canvas.getContext("2d");
    ctx.beginPath();
    ctx.moveTo(x1, y1);
    ctx.lineTo(x2, y2);
    ctx.stroke();

    x1 = x2;
    y1 = y2;
}