downLoadDraw(canvas, ctx, url, x, y, w, h) {
      return new Promise((resolve, reject) => {
        uni.getImageInfo({
          src: url,
          success: (res) => {
            const img = canvas.createImage();
            img.onload = () => {
              console.log(img);
              ctx.drawImage(img, x, y, w, h);
              resolve();
            };
            img.src = res.path; //微信请求返回头像
          },
          fail: (err) => {
            this.$toast("图片加载失败，请稍后重试");
            reject();
            return false;
          },
          complete: (res) => {
            console.log(res);
          },
        });
      });
    },

仅供参考