Control point or shape to follow connector geometry

[Andy]

Ideally I want to restrict a control point for a dynamic connector to
only be positioned somewhere along the line itself, can I do this with
a formula in the control point? The line is likely to be a right angle
connector.

Alternatively, can i constrain another shape to be only positioned
somewhere along the line?

I was considering, dropping a shape over the line. Then if the shape
is moved, repeatedly doing a spatial search to see if the shape is
positioned on the line and if so remembering that position. If I find
the shape has moved away from the line I would reposition it back to
the last known position on the line. Just this seems a rather
complicated solution.

Essentially I have a line on which i need to mark certain positions.

Any suggestions welcomed?

 

[JuneTheSecond]

Dynamic connector is protected against adding control point. Some of static
connectors of old type has control point, you can examine these connectors.

 

[Andy]

I need to use dynamic connectors, so will have to try to constrain
another shape to be positioned over the line.

 

[JuneTheSecond]

If straight line, formula would be simple. Please examine old type connectoers.