It creates all the GUI components and processes events from them. PolygonCanvas is a Canvas that processes events in the polygon drawing area. PolygonTri has the responsibility of drawing the triangulated polygon and calculating the positions of the vertices so the polygon is a Delaunay triangulation. SortableVector extends Vector to allow the sorting of Vectors of Objects that implement the Comparable interface. Point2d represents 2d points with floating point coordinates.
Edge represents a single edge of the triangulation.
StackLayout is a LayoutManager that lays out components in a vertical column. I didn't write it.