RFC: DataVisAnnotationTask tools

[srallen]

The current LightCurveViewer is coupled to the functionality of TESS. It has the function to be able to record an annotation of an x-point and the width of the brush. This appears has a full height column on the plot. This RFC will capture comments on how to add this functionality in addition to other possible annotation tools to the ScatterPlotViewer

We have setup a task type of DataVisAnnotationTask which is similar in structure to the DrawingTask in that it has an array of tools that can be defined. A single tool exists now for Graph2dRangeXTool which corresponds with the current functionality for the annotation with the LightCurveViewer. Going forward, we need to add an SVG layer to the ScatterPlotViewer to listen for events and to render the annotation shapes similar to the InteractionLayer used for the drawing task.

Since we use visx with the ScatterPlotViewer, there area few low level libraries we can use to possibly [achieve this:

• @visx/drag
• @visx/event
• @visx/marker

The ScatterPlotViewer needs this interaction layer built in addition to a component for the column-like shape for the existing Graph2dRangeXTool possibly using the marker library. There isn't a shape component for this now because the LightCurveViewer transfers responsibility for rendering to d3.

In addition, we may want to build two more tool types like:

• A Graph2dRangeYTool that is just like the Graph2dRangeXTool, but has an annotation of a y-point and a height. It would render a shape that was a full row.
• A Graph2dRangeXAndYTool that would either annotate the center x and y point with a width and height or possibly record a range of points. This depends on the data needed for a project that might want to do this. This would render like a rectangle on the plot.

For now, we know projects want to do annotations like TESS, so this a definite future enhancement to the ScatterPlotViewer, particularly for the complex composite viewers that use it.

The lab would need to be updated as well to have a task editor for this, plus the tools available if the appropriate subject viewer was enabled for the workflow.

[srallen]

Noting here this issue #999