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利用html5canvas给图片增加文字水印

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>

<body>
<canvas id=‘myCanvas‘ style="width: 280px; height: 280px" width="280" height="280"></canvas>
<script type="text/javascript">


getImg(‘候经理‘,80);
function getImg(text,fsz){

var c = document.getElementById("myCanvas");
var cxt = c.getContext("2d");
var img = new Image();
img.src = http://www.mamicode.com/‘hj.png‘;
img.onload=function(){//图片加载完成,才可处理
cxt.drawImage(img,0,0,280,280,0,0,280,280);
cxt.save();
cxt.font = fsz+"px Arial";
cxt.textBaseline = ‘middle‘;//更改字号后,必须重置对齐方式,否则居中麻烦。设置文本的垂直对齐方式
cxt.textAlign = ‘center‘;
var tw = cxt.measureText(text).width;
var ftop = c.height/2;
var fleft = c.width/2;
cxt.fillStyle="#ff0000";
cxt.fillRect(fleft-tw/2,ftop-fsz/2,tw,fsz);//矩形在画布居中方式
cxt.fillStyle="#ffffff";
cxt.fillText(text,fleft,ftop);//文本元素在画布居中方式
cxt.strokeStyle = ‘yellow‘;
cxt.strokeText(text,fleft,ftop);//文字边框
};

}

</script>

</body>
</html>

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结果

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利用html5canvas给图片增加文字水印