On 11/12/05, Robert Kern <[EMAIL PROTECTED]> wrote:
Ben Bush wrote:
> is there any code to decide whether a point is located within the circle
> by three other points?
# Converted from my C++ code.
# C.f. http://www.ics.uci.edu/~eppstein/junkyard/circumcenter.html
def circumcenter(x0, y0,
x1, y1,
x2, y2):
x0m2 = x0 - x2
y1m2 = y1 - y2
x1m2 = x1 - x2
y0m2 = y0 - y2
x0p2 = x0 + x2
y1p2 = y1 + y2
x1p2 = x1 + x2
y0p2 = y0 + y2
D = x0m2*y1m2 - x1m2*y0m2
# You probably want to test for D being close to 0 here
centerx = (((x0m2*x0p2 + y0m2*y0p2)/2*y1m2)
- (x1m2*x1p2 + y1m2*y1p2)/2*y0m2) / D
centery = (((x1m2*x1p2 + y1m2*y1p2)/2*x0m2)
- (x0m2*x0p2 + y0m2*y0p2)/2*x1m2) / D
return centerx, centery
def incircle(x0, y0,
x1, y1,
x2, y2,
x, y):
centerx, centery = circumcenter(x0, y0, x1, y1, x2, y2)
return ((x-centerx)**2 + (y-centery)**2 <=
(x0-centerx)**2 + (y0-centery)**2)
--
Robert Kern
[EMAIL PROTECTED]
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter
Thanks!
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