Finding Points On Perimeter Of a Circle

Question

I need to draw line from the centre of a circle. For this I first chose centre of the image as a circle centre and draw a circle with known radius. After that using parametr

Answer 1

sin and cos expect the angle to be in radians. If you provide the angle in degrees, the actual difference will be 6 == 6 - 2 * Pi which is about -16.22°.

So just calculate the radians from degrees:

x = cx + r * cos(a * CV_PI / 180.0)
y = cy + r * sin(a * CV_PI / 180.0)