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function circumcircle(a, b, c) { | |
this.a = a | |
this.b = b | |
this.c = c | |
var A = b.x - a.x, | |
B = b.y - a.y, | |
C = c.x - a.x, | |
D = c.y - a.y, | |
E = A * (a.x + b.x) + B * (a.y + b.y), | |
F = C * (a.x + c.x) + D * (a.y + c.y), | |
G = 2 * (A * (c.y - b.y) - B * (c.x - b.x)), | |
minx, miny, dx, dy | |
/* If the points of the triangle are collinear, then just find the | |
* extremes and use the midpoint as the center of the circumcircle. */ | |
if(Math.abs(G) < 0.000001) { | |
minx = Math.min(a.x, b.x, c.x) | |
miny = Math.min(a.y, b.y, c.y) | |
dx = (Math.max(a.x, b.x, c.x) - minx) * 0.5 | |
dy = (Math.max(a.y, b.y, c.y) - miny) * 0.5 | |
this.x = minx + dx | |
this.y = miny + dy | |
this.r = sqrt(dx * dx + dy * dy) | |
} | |
else { | |
this.x = (D*E - B*F) / G | |
this.y = (A*F - C*E) / G | |
dx = this.x - a.x | |
dy = this.y - a.y | |
this.r = sqrt(dx * dx + dy * dy) | |
} | |
} |
Author
edgar-maciel
commented
Mar 9, 2015
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