Segment

An alternative interpretation of paths that is convenient for mathematical operations.

Here, a path is viewed as a list of segments with a start and end point.

= LineSegment (Vec2 Float) (Vec2 Float)

| Quadratic (Vec2 Float) (Vec2 Float) (Vec2 Float)

| Cubic (Vec2 Float) (Vec2 Float) (Vec2 Float) (Vec2 Float)

| Arc

{ start : Vec2 Float

, end : Vec2 Float

, radii : ( Float, Float )

, xAxisRotate : Float

, arcFlag : ArcFlag

, direction : Direction

}

The four types of segments.

For segments, the xAxisRotate field is in radians.

Operations

at : Float -> Segment -> ( Float, Float )

Get the location at a point on the curve, only defined in the range [0, 1].

length : Segment -> Float

The approximate length of a segment

{ minDepth : Int

, error : Float

}

-> Segment

-> Float

Supply the options for the approximation

minDepth: Minimum recursion depth for calculating the length of arc segments. Default is 10.
error: Minimal amount of progress that an recursive step must make. Default is 1.0e-12.

derivativeAtFirst : Segment -> Float2

The derivative at the starting point of the segment

derivativeAtFinal : Segment -> Float2

The derivative at the ending point of the segment

angle : Segment -> Segment -> Float

The angle between the end of segment1 and the start of segment2

startingPoint : Segment -> Vec2 Float

Extract the starting point from a segment

toDrawTo : Segment -> DrawTo

Convert a segment to a drawto instruction.

toSegment : Segment -> DrawTo -> List Segment

Convert a drawto into a segment

This function needs the previous segment to the starting point and (for bezier curves) the control points