作用
- html2canvas可以通過純JS對瀏覽器端經行截屏，但截圖的精確度還有待提高，部分css不可識別，所以在canvas中不能完美呈現原畫面樣式
支持的瀏覽器
- Firefox 3.5+
- Google Chrome
- Opera 12+
- IE9+
- Safari 6+
基本語法
//兩個參數：所需要截圖的元素id，截圖后要執行的函數， canvas為截圖后返回的最后一個canvas
html2canvas(document.getElementById('id')).then(function(canvas) {document.body.appendChild(canvas);});
可用參數
| 參數名稱 | 類型 | 默認值 | 描述 |
|---|---|---|---|
| allowTaint | boolean | false | Whether to allow cross-origin images to taint the canvas---允許跨域 |
| background | string | #fff | Canvas background color, if none is specified in DOM. Set undefined for transparent---canvas的背景顏色，如果沒有設定默認透明 |
| height | number | null | Define the heigt of the canvas in pixels. If null, renders with full height of the window.---canvas高度設定 |
| letterRendering | boolean | false | Whether to render each letter seperately. Necessary if letter-spacing is used.---在設置了字間距的時候有用 |
| logging | boolean | false | Whether to log events in the console.---在console.log()中輸出信息 |
| proxy | string | undefined | Url to the proxy which is to be used for loading cross-origin images. If left empty, cross-origin images won't be loaded.---代理地址 |
| taintTest | boolean | true | Whether to test each image if it taints the canvas before drawing them---是否在渲染前測試圖片 |
| timeout | number | 0 | Timeout for loading images, in milliseconds. Setting it to 0 will result in no timeout.---圖片加載延遲，默認延遲為0，單位毫秒 |
| width | number | null | Define the width of the canvas in pixels. If null, renders with full width of the window.---canvas寬度 |
| useCORS | boolean | false | Whether to attempt to load cross-origin images as CORS served, before reverting back to proxy--這個我也不知道是干嘛的 |
例子
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title>html2canvas example</title>
<script type="text/javascript" src="html2canvas.js"></script>
</head>
<script type="text/javascript">
function takeScreenshot() {
console.log('test');
html2canvas(document.getElementById('view'), {
onrendered: function(canvas) {
document.body.appendChild(canvas);
},
// width: 300,
// height: 300
});
}
</script>
<body>
<div id="view" style="background:url(test.jpg) 50%; width: 700px; height: 500px;">
<input type="button" value="截圖" onclick="takeScreenshot()">
</div>
</body>
</html>
效果圖
Paste_Image.png
- 截圖后
Paste_Image.png
