This is a very fast version of cir with allowOverlap = TRUE, allowDuplicates = FALSE,
returnIndices = TRUE, returnDistances = TRUE, and includeBehavior = "excludePixels".
It is used inside spread2, when asymmetry is active. The basic algorithm is to run cir
just once, then add to the xy coordinates of every locus

.cirSpecialQuick(landscape, loci, maxRadius, minRadius)

## Arguments

landscape |
Raster on which the circles are built. |

loci |
Numeric. An alternative to `coords` . These are the indices on
`landscape` to initiate this function. See `coords` . Default is one
point in centre of `landscape` .. |

maxRadius |
Numeric vector of length 1 or same length as coords |

minRadius |
Numeric vector of length 1 or same length as `coords` . Default is
`maxRadius` , meaning return all cells that are touched
by the narrow ring at that exact radius. If smaller than `maxRadius` ,
then this will create a buffer or donut or ring. |