trig

func CircleAngleAtPoint ¶

func CircleAngleAtPoint(point, mid image.Point) int

CircleAngleAtPoint given a point on a circle and its midpoint, calculates the angle in degrees. Angles are zero at the X axis and grow counter-clockwise.

func CirclePointAtAngle ¶

func CirclePointAtAngle(degrees int, mid image.Point, radius int) image.Point

CirclePointAtAngle given an angle in degrees and a circle midpoint and radius, calculates coordinates of a point on the circle at that angle. Angles are zero at the X axis and grow counter-clockwise.

func FilterByAngle ¶

func FilterByAngle(points []image.Point, mid image.Point, start, end int) ([]image.Point, error)

FilterByAngle filters the provided points, returning only those that fall within the starting and the ending angle on a circle with the provided mid point.

func PointIsIn ¶

func PointIsIn(p image.Point, points []image.Point) bool

PointIsIn asserts whether the provided point is inside of a shape outlined with the provided points. Does not verify that the shape is closed or complete, it merely counts the number of intersections with the shape on one row.

func RangeMid ¶

func RangeMid(start, end int) (int, error)

RangeMid returns an angle that lies in the middle between start and end. E.g:

0,10   => 5
350,10 => 0

func RangeSize ¶

func RangeSize(start, end int) (int, error)

RangeSize returns the size of the degree range. E.g:

0,25  => 25
359,1 => 2