Uncaught ReferenceError: cnavasa is not defined
现实PK理想
2015-09-24 18:38
var imagedate=contexta.getImageData(0,0,canvasa.width,cnavasa.height);为什么会报错 求解
3回答
-
- 杜新明
- 2016-11-24 10:49:27
在本机搭建的web服务器环境下运行
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- 现实PK理想
- 2015-09-25 09:07:25
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
</style>
</head>
<body>
<div style="margin: 20px auto; width:1700px;">
<canvas id="canvasa" width="800" height="560" style="display:block;float:left;border:1px solid #aaa;">
</canvas>
<canvas id="canvasb" width="800" height="560" style="display:block;float:right;border:1px solid #aaa;">
</canvas>
</div>
<a href="javascript:filter()">filter</a>
<script language="javascript">
var canvasa=document.getElementById("canvasa");
var contexta=canvasa.getContext("2d");
var canvasb=document.getElementById("canvasb");
var contextb=canvasb.getContext("2d");
var img=new Image()
window.onload=function(){
img.src="css精美案列/55d4263e00019bed00000000/canvas-image/05-image-filter/autumn.jpg";
img.onload=function(){
contexta.drawImage(img,0,0,canvasa.width,canvasa.height);
}
}
function filter(){//下面这句话一直报错原因是未能执行“getImageData”“CanvasRenderingContext2D“，
var imagedata=contexta.getImageData(0,0,canvasa.width,canvasa.height);
contextb.putImageData(imagedata,0,0,0,0,canvasb.height,canvasb.width);
console.log("ok");
}
</script>
</body>
</html> -
- 化龙贝
- 2015-09-24 19:08:23
contexta 是神马？
Canvas玩转图像处理
60396 学习 · 127 问题
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