translate-image.js

/**

* 压缩

* @param {Object} imgSrc 图片url

* @param {Object} callback 回调设置返回值

*/

export function translate(imgSrc,callback) {

var img = new Image();

img.src = imgSrc;

img.onload = function() {

var that = this;

var h = that.height;

// 默认按比例压缩

var w = that.width;

var canvas = document.createElement('canvas');

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

var anw = document.createAttribute("width");

anw.nodeValue = w;

var anh = document.createAttribute("height");

anh.nodeValue = h;

canvas.setAttributeNode(anw);

canvas.setAttributeNode(anh);

ctx.drawImage(that, 0, 0, w, h);

//压缩比例

var quality = 0.1;

var base64 = canvas.toDataURL('image/jpeg', quality);

canvas = null;

var blob=base64ToBlob(base64);

// console.log(blob)

//Blob对象转blob地址

var blobUrl=window.URL.createObjectURL(blob);

callback(blobUrl);

}

}

/**

* base转Blob对象

* @param {Object} base64 base64地址

*/

export function base64ToBlob(base64) {

var arr = base64.split(','),

mime = arr[0].match(/:(.*?);/)[1],

bstr = atob(arr[1]),

n = bstr.length,

u8arr = new Uint8Array(n);

while (n--) {

u8arr[n] = bstr.charCodeAt(n);

}

return new Blob([u8arr], {

type: mime

});

}

调用压缩方法