CGAL 5.1.3 - 2D Envelopes

## Concepts

conceptEnvelopeDiagram_1
This concept defines the representation of an envelope diagram of a set of planar curve. The envelope diagram is a subdivision of the $$x$$-axis into 0-dimensional cells (vertices) and 1-dimensional cells (edges), such that the identity of the curves that induce the lower envelope (or the upper envelope) over each cell is fixed. More...

conceptEnvelopeDiagramEdge
An edge record in an envelope diagram, which represents a continuous portion of the $$x$$-axis. It is associated with a (possibly empty) set of curves that induce the envelope over this portion of the $$x$$-axis. Note that all curves in this set overlap over the interval represented by the edge. More...

conceptEnvelopeDiagramVertex
A vertex record in an envelope diagram. It is always associated with a point on the lower (upper) envelope of a non-empty set of curves. A vertex is also associated with a set of $$x$$-monotone curves that induce the envelope over this point. It is incident to two edges, one lying to its left and the other to its right. More...