Annotation editing support in toolbox

What problem does this feature solve?

Currently there is no easy way for a user to add annotations to a chart. The data can be initialised with labelled points but for my use case, I need my data analysts to be able to highlight a chart area and directly add annotations in a similar way to http://demo.blacklabel.pl/ (see the buttons in the top right: text, rectangle)

What does the proposed API look like?

1. The toolbox would be able to be initialised with addAnnotations: true - this would add buttons in the top right corner similar to http://demo.blacklabel.pl/

2. When annotations are added, an event would be triggered with a payload like this:

{
   annotationAdded: { annotationType: 'rectangle', annotationText: 'blah', annotationXMin: 123, annotationXMax: 150, annotationYMin: 100, annotationYMax: 200 },
   allAnnotations: [{ annotationType: 'rectangle', annotationText: 'blah', annotationXMin: 123, annotationXMax: 150, annotationYMin: 100, annotationYMax: 200 }]
}

[tomasz-zablocki-ziegert]

It’s the only missing feature that makes our team hesitant about adopting echarts for our product. It’s already a majority of our customers that made it clear that it’s a mandatory to have it.

[Ovilia]

Yes. We are considering enhance labeling feature with annotation. There shall be much work to do, and it is scheduled in ECharts v5, which we haven’t begin with yet.