// 压缩上传图片
export function translate(imgSrc, scale, fileName, callback) {
	let img = new Image();
	img.src = imgSrc;
	img.onload = function() {
		let that = this;
		let h = that.height * 0.8; // 默认按比例压缩
		let w = that.width * 0.8;
		let canvas = document.createElement('canvas');
		let ctx = canvas.getContext('2d');
		let width = document.createAttribute("width");
		width.nodeValue = w;
		let height = document.createAttribute("height");
		height.nodeValue = h;
		canvas.setAttributeNode(width);
		canvas.setAttributeNode(height);
		ctx.drawImage(that, 0, 0, w, h);
		// 设置边框样式
		ctx.strokeStyle = '#fff';
		ctx.lineWidth = 5;
		ctx.strokeRect(0, 0, w, h);
		let dataurl = canvas.toDataURL('image/jpeg', scale); //压缩比例
		let arr = dataurl.split(','),
			mime = arr[0].match(/:(.*?);/)[1],
			bstr = atob(arr[1]),
			n = bstr.length,
			u8arr = new Uint8Array(n);
		while (n--) {
			u8arr[n] = bstr.charCodeAt(n);
		}
		let file = new File([u8arr], fileName, {
			type: mime
		});
		// file.lastModifiedDate = new Date();
		canvas = null;
		callback && callback(dataurl, file);
	}
}