Computes the area of that part of a disc that is not covered by other discs.
areaLoss(X, r, ..., W=as.owin(X), subset=NULL,
                 exact=FALSE,
                 ngrid=spatstat.options("ngrid.disc"))A matrix with one row for each point in X (or X[subset])
  and one column for each value in r.
Locations of the centres of discs.
    A point pattern (object of class "ppp").
Disc radius, or vector of disc radii.
Ignored.
Optional. Window (object of class "owin")
    inside which the area should be calculated.
Optional. Index identifying a subset of the points of X
    for which the area difference should be computed.
Choice of algorithm.
    If exact=TRUE, areas are computed exactly using
    analytic geometry. If exact=FALSE then a faster algorithm
    is used to compute a discrete approximation to the areas.
Integer. Number of points in the square grid used to compute
    the discrete approximation, when exact=FALSE.
Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner rolfturner@posteo.net
This function computes, for each point X[i] in X
  and for each radius r,
  the area of that part of the disc of radius r centred at the
  location X[i] that is not covered by any of the
  other discs of radius r centred at the points X[j]
  for j not equal to i.
  This area is important in some calculations related to
  the area-interaction model AreaInter.
The result is a matrix, with one row for each point in X
  and one column for each entry of r.
AreaInter,
  areaGain,
  dilated.areas