Supporting visual charts that lack semantic structure/APIs

[matatk]

Technologies like SVG and D3 can be used to create visual, interactive, charts. However they lack chart-specific APIs that AudioChart can use directly (such as to "visually select/highlight series 0, datum 42", for example, whilst the chart is being played back). But AudioChart can load data from raw JSON objects and HTML tables, and with a little bit of work it should be possible for content authors to write hooks that can be used as visual callbacks. Therefore this issue is really about two things:

1. Seeing how much effort is needed to interface with less-structured visual charts
   • the data behind them
   • visual highlighting
2. Providing clear documentation and examples as to how.

Some things that should help:

• The backing data should already be available, either already on the page (as HTML table, or JSON) or it could be made available. (Making an example of this for users to follow should be considered MVP.)
• One specific idea re SVG would be to latch on to existing markup such as when ARIA has been used to give table semantics to the SVG. (This could be considered MVP+1.)