@verb #1177:"area" this none this rxdo #1177
@program #1177:"area" this none this
"Copied from Terra (#1000):area by Hacker (#60) Aug 31 08:21:02 2002"
":area(x) => {{0, 0}, {0, 1}, {0, -1}, ...}"
"Returns a list of all x/y tuples that fall within a circle of radius x"
{radius} = args
quarter = {}
for y in [1..radius]
  arc = cos($pi / 2.0 / tofloat(radius) * tofloat(y)) * tofloat(radius)
  for x in [1..toint(arc + 0.5)]
    quarter = {@quarter, {x, y}}
  endfor
endfor
area = {{0, 0}}
for z in [1..radius]
  area = {@area, {0, z}, {0, -z}, {z, 0}, {-z, 0}}
endfor
for z in (quarter)
  area = setadd(area, {z[1], z[2]})
  area = setadd(area, {z[2], z[1]})
  area = setadd(area, {-z[1], z[2]})
  area = setadd(area, {-z[2], z[1]})
  area = setadd(area, {-z[1], -z[2]})
  area = setadd(area, {-z[2], -z[1]})
  area = setadd(area, {z[1], -z[2]})
  area = setadd(area, {z[2], -z[1]})
endfor
"area = $list_utils:remove_duplicates(area)"
return area
.