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
