CODEWITHSUNDEEP
pythongeometry
hadim
hadim

Reputation: 646

How to calculate all the points defining two crossing circles in Python?

I want to calculate the points defining two crossing circles in Python. See the plot below of the points I want to calculate.

enter image description here

I have the following algorithm to calculate the point defining one circle : 

def get_circle_points(x_center, y_center, radius, n=20):
    xpoints = []
    ypoints = []
    for i in range(0, n+1):
        x = math.cos(2*math.pi/n*i) * radius + x_center
        y =  math.sin(2*math.pi/n*i) * radius + y_center
        xpoints.append(x)
        ypoints.append(y)
    return xpoints, ypoints

One important limitation is that I can't import numpy, only pure Python answer are ok.

Upvotes: 0

Views: 100

Answers (1)

MBo
MBo

Reputation: 80187

Very simple approach (with some excessive calculations):

Get start angle as

sa = atan2(yc2-yc1, xc2-xc1)

Generate the first circle points in angle range sa..sa + 2*Pi

Check - if point (px,py) is outside the second circle, add it to result list (px-cx2)^2+(py-cy2)^2 > r2^2

Generate the second circle points in angle range sa - Pi..sa + Pi

Check - if point (px,py) is outside the first circle, add it to result list (px-cx1)^2+(py-cy1)^2 > r1^2

More effective approach - calculate intersection points angles and scan only needed angle ranges.

Upvotes: 1

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