How to get angle of point from center point?

Question

If I have 2 points (x0,y0) which is the center of the circle, and another point (x,y) (this is the red dot on the circle boundary in the image). How can I get the angle of the d

Answer 1

You were very close :-)

Change this:

 angle = atan(float(dy)/float(dx))

To this:

 angle = degrees(atan2(float(dy), float(dx)))

The atan2() function is between than atan() because it considers the signs to the inputs and goes all the way around the circle:

atan2(...)
    atan2(y, x)

    Return the arc tangent (measured in radians) of y/x.
    Unlike atan(y/x), the signs of both x and y are considered

The degrees() function converts from radians to degrees:

degrees(...)
    degrees(x)

    Convert angle x from radians to degrees.

Also, as Rich and Cody pointed-out you need to fix your dy calculation.