Determines whether a window is convex.
is.convex(x)Window (object of class "owin").
Logical value, equal to TRUE if x is convex.
If x is a rectangle, the result is TRUE.
If x is polygonal, the result is TRUE if x consists of a
single polygon and this polygon is equal to the minimal convex hull
of its vertices computed by chull.
If x is a mask, the algorithm first extracts all boundary
pixels of x using vertices. Then it computes
the (polygonal) convex hull \(K\) of the boundary pixels.
The result is TRUE if every boundary pixel lies within
one pixel diameter of an edge of \(K\).