<!-- index.ttml -->
<camera class="camera" device-position="back" flash="off" binderror="onError"></camera>
<button type="primary" bindtap="createContext">授权并创建cameraContext</button>
<button type="primary" bindtap="setZoom">设置缩放级别</button>

// index.js
Page({
  onError(e) {
    tt.showModal({
      title: "相机出错",
      content: JSON.stringify(e),
      showCancel: false,
    });
  },
  createContext() {
    tt.getSetting({
      success: (res) => {
        let cameraAllowed = res.authSetting["scope.camera"];
        if (cameraAllowed) {
          this.ctx = tt.createCameraContext();
        } else {
          tt.showToast({
            title: "请授权相机后重新进入",
          });
        }
      },
      fail: (err) => {
        tt.showModal({
          title: "获取授权失败",
          content: JSON.stringify(err),
        });
      },
    });
  },
  setZoom() {
    this.ctx.setZoom({
      zoom: 8,
      success(res) {
        tt.showToast({
          title: `设置 zoom 为: ${res.zoom}`,
        });
      },
      fail(err) {
        tt.showModal({
          content: `设置缩放失败: ${JSON.stringify(err)}`,
        });
      },
    });
  },
});