Get geolocation from clicking on a map

[FlorianJacta]

Description

The goal would be to get the lon/lat of a point when clicking anywhere on a map.

This was asked by a user here

Acceptance Criteria

• Ensure new code is unit tested, and check code coverage is at least 90%.
• Create related issue in taipy-doc for documentation and Release Notes.
• Check if a new demo could be provided based on this, or if legacy demos could be benefit from it.
• Ensure any change is well documented.

Code of Conduct

• I have checked the existing issues.
• I am willing to work on this issue (optional)

[FabienLelaquais]

So that's going to be a tricky one because of the nature of the chart control.
We may consider an on_click callback that would be invoked when users click the chart, and fill a payload with as much information as we get - such as lat/lon in the case of a georeferenced dataset...

[FredLL-Avaiga]

Taipy uses plotly.js for displaying charts
Plotly.js doesn't allow natively to catch click event on the background of charts.
But there is a way (a bit hacky)

• we can add a event listener to the chart div
• then get the information from a non public structure in plotly.js

plotlyDiv.addEventListener('click', function(evt) {
    console.log("click", "latitude", plotlyDiv._fullLayout.map._subplot.yaxis.p2c(), "longitude", plotlyDiv._fullLayout.map._subplot.xaxis.p2c());})

and make it available via a standard Taipy callback on_click

[FredLL-Avaiga]

Interesting: there's a PR opened for this (for the last 6 years)
plotly/plotly.js#5443