压缩图片原地址https://my.oschina.net/u/3362856/blog/1162498
chooseImage: function (e) {//上传照片
var that = this;
wx.chooseImage({
count:1,//最多可以选择的图片张数，默认9
sizeType: [ 'compressed'], // 可以指定是原图还是压缩图，默认二者都有
sourceType: ['album', 'camera'], // 可以指定来源是相册还是相机，默认二者都有
success: function (res) {
// 返回选定照片的本地文件路径列表，tempFilePath可以作为img标签的src属性显示图片
that.setData({
files: res.tempFilePaths[0]
});
}
})
},
drawCanvas:function(){// 缩放图片
const ctx = wx.createCanvasContext('attendCanvasId');
let that=this;
wx.getImageInfo({
src: that.data.files,
success:function (res) {
if(res.width>500||res.height>500){//判断图片是否超过500像素
let scale=res.width/res.height//获取原图比例
that.setData({//构造画板宽高
canWidth:500,
canHeight:500/scale
})
//画出压缩图片
ctx.drawImage(that.data.files, 0, 0, that.data.canWidth, that.data.canHeight);
ctx.draw();
//等待压缩图片生成
var st =setTimeout(function(){
that.prodImageOpt();
clearTimeout(st);
},3000);
}else{
//上传图片
that.uploadFileOpt(that.data.files);
}
}
})
},
prodImageOpt:function(){// 获取压缩图片路径
var that =this;
wx.canvasToTempFilePath({
canvasId:'attendCanvasId',
success:function success(res) {
// 上传图片
that.uploadFileOpt(res.tempFilePath);
},
});
},
uploadFileOpt:function(path){//上传图片
let that=this;
wx.uploadFile({
url:'/api/uploadPath', //后台上传api路径
filePath: path,
name:'file',
success:function(res){
console.log(res);//因uploadFile无法在network中捕获故需打印返回内容
//to do
},
fail:e=>{
//to do
}
})
}
