Dynamic label for nearest visible Narrative Entry

[IanMayo]

The narrative entries add valuable extra context to what's happening on the plot.

If the narrative entry was displayed next to the current vessel position, it would associate that extra detail with the platform it relates to, at the relevant time.

One solution to this is a modification to the Snail Painter. If on, then the nearest visible narrative entry for that platform would be displayed. I think we would need to know the "window" of time around time-now that a narrative is relevant. It could be anywhere from 5 seconds to 15 minutes.

I guess we need these options:

• Show nearest visible narrative: boolean
• Nearest Narrative Font: font
• Nearest time window: seconds

These options would fall in a new Narrative Entry section of Snail Properties:

These values should be persisted as new SnailPainter properties in the DPF (xml) file. I'm happy to handle this persistence, if necessary. The new properties would go in the <gui><component> section.

A good datafile to Drive this issue is sample.dpf - since it carries narratives and tracks.

Update: Pause on this task until the clients have considered the best way of providing it. EB suggested one route to providing it could be through the optional Label/Comment field on position entries.