Snapshots

[miralemd]

Snapshots play a key role in exporting images and storytelling.

When a component is exported, a snapshot is taken of the current layout and is then rendered in the backend using that layout. This works fairly well as long as the enigma model is not used to e.g. fetch more data.

The developer should therefore be allowed to control what is included in the snapshot in order to reproduce the state of the component without the presence of a backend.

component: {
  render({ layout, context }) {
    if (layout.additionalData) { // assume a snapshot is being rendered
      // render stuff
    } else if (context.permissions.indexOf('fetch') !== -1) { // access to engine is permitted
      this.model.getHyperCubeData(/* */).then((pages) => {
        this.additionalData = pages; // temporarily store the data
      });
    }
  },
  takeSnapshot({ layout }) {
    // store the additional data
    layout.additionalData = this.additionalData;
  }
}

Related to #26