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include <mach.h>
# MK_FIND -- Procedure to detect the object in a file closest to the
# input cursor position.
int procedure mk_find (cl, xcur, ycur, xlist, ylist, label, id, ltid, tol)
int cl # coordinates file descriptor
real xcur, ycur # x and y cursor position
real xlist, ylist # x and y list position
char label[ARB] # label string
int id # sequence number of detected object in list
int ltid # current sequence number in the list
real tol # tolerance for detection
real x, y, dist2, ldist2, tol2
int fscan(), nscan()
begin
if (cl == NULL)
return (0)
call seek (cl, BOF)
ltid = 0
# Initialize
id = 0
dist2 = MAX_REAL
tol2 = tol ** 2
# Fetch the coordinates.
while (fscan (cl) != EOF) {
call gargr (x)
call gargr (y)
call gargwrd (label, SZ_LINE)
if (nscan () < 2)
next
if (nscan () < 3)
label[1] = EOS
ltid = ltid + 1
ldist2 = (x - xcur) ** 2 + (y - ycur) ** 2
if (ldist2 > tol2)
next
if (ldist2 > dist2)
next
xlist = x
ylist = y
dist2 = ldist2
id = ltid
}
return (id)
end
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