使用html2canvas实现浏览器截图,必须在服务器环境下才能实现。
作用html2canvas可以通过纯JS对浏览器端经行截屏，但截图的精确度还有待提高，部分css不可识别，所以在canvas中不能完美呈现原画面样式
/*多行溢出省略就不行，只能超出隐藏了*/ .book_inf{ position: relative; overflow : hidden; text-overflow: ellipsis; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; }支持的浏览器/*参数：* #screenshots 所需要截图的元素id，截图后要执行的函数，* backgroundColor 配置项背景色* canvas为截图后返回的最后一个canvas*/function screenshotsImg(){ html2canvas(document.querySelector(#screenshots),{ backgroundColor: 'transparent',// 设置背景透明 }).then(canvas => { canvasTurnImg(canvas) //保存的图片格式转换方法 }); }可用配置项| 参数名称 | 类型 | 默认值 | 描述 |
|---|---|---|---|
| allowTaint | boolean | false | Whether to allow cross-origin images to taint the canvas---允许跨域 |
| background | string | #fff | Canvas background color, if none is specified in DOM. Set undefined for transparent---canvas的背景颜色，如果没有设定默认白色此处被坑，我改为backgroundColor可用 |
| height | number | null | Define the heigt of the canvas in pixels. If null, renders with full height of the window.---canvas高度设定 |
| letterRendering | boolean | false | Whether to render each letter seperately. Necessary if letter-spacing is used.---在设置了字间距的时候有用 |
| logging | boolean | false | Whether to log events in the console.---在console.log()中输出信息 |
| 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---是否在渲染前测试图片 |
| timeout | number | 0 | Timeout for loading images, in milliseconds. Setting it to 0 will result in no timeout.---图片加载延迟，默认延迟为0，单位毫秒 |
| width | number | null | Define the width of the canvas in pixels. If null, renders with full width of the window.---canvas宽度 |
| useCORS | boolean | false | Whether to attempt to load cross-origin images as CORS served, before reverting back to proxy--跨域代理 |
1、从canvas中直接提取图片元数据
// 图片导出为 png 格式 var type = 'png'; var imgData = canvas.toDataURL(type);
2、将mime-type改为image/octet-stream，强制让浏览器直接download
/** * 获取mimeType * @param {String} type the old mime-type * @return the new mime-type */var _fixType = function(type) { type = type.toLowerCase().replace(/jpg/i, 'jpeg'); var r = type.match(/png|jpeg|bmp|gif/)[0]; return 'image/' + r;}; // 加工image data，替换mime typeimgData = imgData.replace(_fixType(type),'image/octet-stream');3、图片download到本地
/** * 在本地进行文件保存 * @param {String} data 要保存到本地的图片数据 * @param {String} filename 文件名 */var saveFile = function(data, filename){ var save_link = document.createElementNS('http://www.w3.org/1999/xhtml', 'a'); save_link.href = data; save_link.download = filename; var event = document.createEvent('MouseEvents'); event.initMouseEvent('click', true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null); save_link.dispatchEvent(event);}; // 下载后的文件名var filename = 'baidufe_' + (new Date()).getTime() + '.' + type;// downloadsaveFile(imgData,filename);案例
案例
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