在画布上绘制多边形时的间隙

Question

我正在使用以下内容在html画布上绘制多边形：

var canvas = document.getElementById("mycanvas");
var ctx = canvas.getContext("2d");

var numberOfSides = 6,
    size = 20,
    Xcenter = 25,
    Ycenter = 25;

ctx.beginPath();
ctx.moveTo (Xcenter +  size * Math.cos(0), Ycenter +  size *  Math.sin(0));          

for (var i = 1; i <= numberOfSides;i += 1) {
    ctx.lineTo (Xcenter + size * Math.cos(i * 2 * Math.PI / numberOfSides), Ycenter + size * Math.sin(i * 2 * Math.PI / numberOfSides));
}

ctx.strokeStyle = "#000000";
ctx.lineWidth = 10;
ctx.stroke();

不幸的是，它在多边形的末端留下了间隙。 任何想法如何解决这个问题？

Jsfiddle在这里

Answer 1

不必绘制所有6个点，而仅绘制前5个，然后调用ctx.closePath();

http://jsfiddle.net/757mavjb/2/

var canvas = document.getElementById("mycanvas");
var ctx = canvas.getContext("2d");

var numberOfSides = 6,
    size = 20,
    Xcenter = 25,
    Ycenter = 25;

ctx.beginPath();
ctx.moveTo (Xcenter +  size * Math.cos(0), Ycenter +  size *  Math.sin(0));          

for (var i = 1; i < numberOfSides;i += 1) {
    ctx.lineTo (Xcenter + size * Math.cos(i * 2 * Math.PI / numberOfSides), Ycenter + size * Math.sin(i * 2 * Math.PI / numberOfSides));
}
ctx.closePath();

ctx.strokeStyle = "#000000";
ctx.lineWidth = 10;
ctx.stroke();

（请注意，从i <= numberOfSides更改为i < numberOfSides ）

Answer 2

尝试多画一点以填补空白：

for (var i = 1; i <= numberOfSides+1;i += 1) {
    ctx.lineTo (Xcenter + size * Math.cos(i * 2 * Math.PI / numberOfSides), Ycenter + size * Math.sin(i * 2 * Math.PI / numberOfSides));
}