var image = new Image()

					// 网络图片 处理跨域问题

					image.setAttribute('crossOrigin', 'anonymous')

					image.src = img

					image.onload = () => {

						//width、height调用时传入具体像素值，控制大小 ,不传则默认图像大小

						var canvas = document.createElement("canvas")

						canvas.width = width ? width : image.width

						canvas.height = height ? height : image.height

						var ctx = canvas.getContext("2d")

						// // 创建图片纹理

						var pattern = ctx.createPattern(image, "no-repeat")

						// 如果是正方形图片

						if (canvas.width == canvas.height) {

							console.log('正方形')

							// // 绘制一个圆

							ctx.arc(canvas.width/2, canvas.height/2, canvas.width/2, 0, 2 * Math.PI)

							// // 填充绘制的圆

							ctx.fillStyle = pattern

							ctx.fill()

						}else {

							console.log('长方形')

							ctx.save();

							ctx.arc(image.width/2, image.height/2, Math.min(image.width, image.height) / 2, 0, 2 * Math.PI);

							// 从画布上裁剪出这个圆形

							ctx.clip();

							canvas.width = width ? width : image.width/2

							canvas.height = height ? height : image.width/2

							ctx.drawImage(image, 0, 0, Math.min(image.width, image.height) / 2, Math.min(image.width, image.height) / 2);

							ctx.restore();

							ctx.clearRect(0, 0, canvas.width, canvas.height);    //清空画布

							// // 绘制一个圆

							ctx.arc(canvas.width/2, canvas.height/2, canvas.width/2, 0, 2 * Math.PI)

							// // 填充绘制的圆

							ctx.fillStyle = pattern

							ctx.fill()

						}

						var dataURL = canvas.toDataURL()

						_this.avatar = dataURL