Basic math often eludes me. I was working on a graph and realized I didn’t remember how to rotate something outside 90° chunks.
radians = degrees * (pi/180)
To rotate a set of points in 2d. Move the group of points so their center is at the origin (0,0). Keep track of how much you adjusted the x and y coords to move the shape back once you have rotated it, then adjust the X,Y for each point:
new x = x * cos(radians) – y * sin(radians)
new y = y * cos(radians) + x * sin (radians)
add the x and y shift the point wasmoved . If you want to rotate clockwise inverse the angle or flip the operations +,- for new x and y