Decide the arrow graphics item's docking point

[sajis997]

Hi forum,

This may be a more a mathematical question that the qt related one, but i need to post it here just in case some one might know.

Which point on the ellipse gives the shortest distance from the mouse click position inside the ellipse ?



Regards
Sajjad

[ChrisW67]

The Diagram Scene Example does this sort of thing for polygonal objects by looking for the intersection of the arrow line and each line in the polygon. You cannot do this for the ellipse though, and I cannot see an obvious Qt way to do this (there may be one though).

For ellipses you will need to do more maths. For ellipse where an axis is horizontal then this is trivial: http://mathworld.wolfram.com/Ellipse...ersection.html. For ellipses in other orientations you may need to rotate first. For partial ellipses the problem is much more difficult.