用图片填充HTML5弧 - HTML5 Canvas [英] Fill HTML5 arc with a picture - HTML5 Canvas

问题描述

我有一个HTML5画布（ JSFiddle ）看起来像：

I have a HTML5 Canvas (JSFiddle) that looks like:

我通过以下方法创建球：

I am creating the balls by the following method:

function createball(x,y,r,color){
    context.beginPath();
    context.arc(x,y,r,0,Math.PI*2,true);
    context.fillStyle = color;
    context.fill();

}

如何用图像填充球？我的意思是一个可能有图案或一些自然色的图像？

How can I fill the ball with image? I mean a image that might have patters or some natural color?

推荐答案

您可以创建一个模式并将球的fillStyle设置为该模式

You could create a pattern and set the ball's fillStyle to that pattern

这是示例代码和演示：

var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var cw=canvas.width;
var ch=canvas.height;


var img=new Image();
img.onload=start;
img.src="https://dl.dropboxusercontent.com/u/139992952/multple/checkerboard.jpg";
function start(){
  var pattern=ctx.createPattern(img,'repeat');
  ctx.beginPath();
  ctx.arc(50,50,15,0,Math.PI*2);
  ctx.closePath();
  ctx.fillStyle=pattern;
  ctx.fill();
  ctx.stroke();
}

body{ background-color: ivory; }
#canvas{border:1px solid red;}

<h4>Source Image:</h4>
<img src='https://dl.dropboxusercontent.com/u/139992952/multple/checkerboard.jpg'>
<h4>Fill Circle with pattern made from source image</h4>
<canvas id="canvas" width=100 height=100></canvas>

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