pfc 2d Example 1.3 Use of a FISH range element

Example 1.3 Use of a FISH range element
;fname: range2.dat
new
set random
generate x=0,100 y=0,100 rad=1.1,1.1 id=1,1000
;
def circle_element
range_element
;
; ----- Defines a FISH range element that determines whether an object
; lies within a circle of radius [ce_rad] with center at
; ([ce_x], [ce_y]).
;
; INPUT: fc_arg(0) - object being queried for range inclusion
; fc_arg(1) - object position (x-component)
; fc_arg(2) - object position (y-component)
; ce_x, ce_y - center of circle
; ce_rad - radius of circle
;
; RETURN VALUE: 0 - object does not lie within circle

; When called, function value is initialized to 1.
;
_x = fc_arg(1)
_y = fc_arg(2)
_dist = sqrt( (_x - ce_x)?2 + (_y - ce_y)?2 )
if _dist > ce_rad then ; bp is not within the circle
circle_element = 0
end_if
end