Intersection Detection
This demo showcases how to find and highlight intersections and overlaps between graph
items.
The
Intersections
algorithm calculates all geometric intersections between nodes, edges, and labels in a
diagram. Checking whether items overlap can be helpful in various scenarios. For example,
you could check if a newly inserted or moved graph item intersects other items. Or, more
generally, if there are overlaps, a layout algorithm could be applied to rearrange the
graph and resolve the overlaps.
The result of the algorithm is provided as a list of
Intersection
objects, where each one represents the intersection between exactly two elements and
additionally provides the exact points describing the shape of the intersection. The
shapes of the intersections are visualized in this demo using different colors for
different kind of intersections (see righthand panel).
Things to Try

Observe the intersections
in the provided initial sample graph. They are highlighted using different colors, while
the actual graph items are painted in gray.

Move a graph item
to see how the result of the intersection algorithm changes. The result is recomputed
on the fly when modifying the graph.

Explore the settings
of the intersection algorithm in the righthand sidebar.