User interaction: measurement between two points

[choucavalier]

I need to implement a domain-specific user interaction on a plot I am building.

The user needs to be able to measure the "distance" between two points.

For that, I need the user to be able to manually trace a segment between two points on the plot (not limited to actual lines, the points can be anywhere).

Is there a way to implement that user interaction with mosaic at the moment?

I feel like this is currently not part of the specs.

If it's not possible to represent that symbolically in the specs, it means that this should be implemented with custom JavaScript (D3.js probably?). Is there any guideline / example for how to extend a mosaic plot with custom D3.js code?

Thanks ❤️

[domoritz]

I don't understand the user interaction you are looking for but to implement custom clients, you can look at these docs: https://idl.uw.edu/mosaic/web-clients/.

[jheer]

My understanding is that you'd like users to be able to:

1. Draw out an interval between two points (a, b) along an axis
2. Display the distance between the points in data units ((b - a) or a date diff)

I don't think this is achievable with the current declarative specs. You could create a param and bind an interval selection to it to capture a user selected interval, but there's no way to then calculate the distance between interval end points within the spec.

However, if you are using the JS API (not a YAML or JSON spec) there should be some relatively simple things you could do:

• Listen to changes to the interval "span" param and update two other params (one for each endpoint) that then drive updates to other Mosaic plots, or
• Add your own web component that simply listens to changes on the interval span param and updates the displayed distance. I don't think any other integration with the Mosaic architecture would be needed.