Base64 PNG数据到HTML5画布

一尘不染

Base64 PNG数据到HTML5画布

html

我想将以Base64编码的PNG图像加载到canvas元素。我有以下代码：

<html>
<head>
</head>
<body>
<canvas id="c"></canvas>
<script type="text/javascript">

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

data =  "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAIAAAACDbGyAAAAAXNSR0IArs4c6QAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB9oMCRUiMrIBQVkAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAADElEQVQI12NgoC4AAABQAAEiE+h1AAAAAElFTkSuQmCC";

ctx.drawImage(data, 0, 0);

</script>
</body>
</html>

在Chrome 8中，我收到错误消息： Uncaught TypeError: Type error

在Firefox的Firebug中，这是：“对象的类型与与该对象关联的参数的预期类型不兼容”代码：“ 17”

在那个base64中，是我在GIMP中制作的5x5px黑色PNG正方形，并将其转换为GNU / Linux程序base64中的base64。

阅读 378

2020-05-10

共1个答案

一尘不染

从外观上看，您实际上需要像这样传递一个imageImage对象

var canvas = document.getElementById("c");

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



var image = new Image();

image.onload = function() {

  ctx.drawImage(image, 0, 0);

};

image.src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAIAAAACDbGyAAAAAXNSR0IArs4c6QAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB9oMCRUiMrIBQVkAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAADElEQVQI12NgoC4AAABQAAEiE+h1AAAAAElFTkSuQmCC";


<canvas id="c"></canvas>

我已经在chrome中尝试过了，效果很好。

2020-05-10