onChooseImage() {
				uni.chooseImage({
					count: 1,
					sizeType: ['compressed'],
					fail: () => {
						this.$u.toast('选择照片失败')
					},
					success: (res) => {
						let blob = res.tempFilePaths[0]

						//获取blob
						this.blobToBase64(blob, 300).then(res => {
							console.log('base64=='+res)

						})
					}
				})
			},
			blobToBase64(blob, wid) {
				return new Promise((resolve, reject) => {
					let image = new Image();
					image.onload = function() {
						let canvas = document.createElement('canvas');
						var w = this.naturalWidth,
							h = this.naturalHeight,
							scale = w / h;
						w = wid || w;
						h = w / scale;
						canvas.width = w
						canvas.height = h;
						// 将图片插入画布并开始绘制
						canvas.getContext('2d').drawImage(image, 0, 0, w, h);
						// result
						let result = canvas.toDataURL('image/png')
						resolve(result);
					};
					image.setAttribute("crossOrigin", 'Anonymous');
					image.src = blob;
					// 图片加载失败的错误处理
					image.onerror = () => {
						reject(new Error('urlToBase64 error'));
					};
				})
			},