SweptAngle

When constructing circular or elliptical arcs, it is sometimes necessary to specify which of several possible arcs you want. For example, if you ask for a circular arc from the point (1, 0) to the point (0, 1) with a radius of 1, there are four possible solutions:

An arc with a swept angle of 90 degrees, with center point at (0, 0)
An arc with a swept angle of -270 degrees, with center point at (0, 0)
An arc with a swept angle of -90 degrees, with center point at (1, 1)
An Arc with a swept angle of 270 degrees, with center point at (1, 1)

The SweptAngle type is used in these cases to specify which arc you want.

type alias SweptAngle =

SweptAngle

Indicate which of four possible arcs you would like to construct. Used by Arc2d.withRadius and EllipticalArc2d.fromEndpoints.

smallPositive : SweptAngle

Construct a counterclockwise arc with a swept angle between 0 and 180 degrees.

smallNegative : SweptAngle

Construct a clockwise arc with a swept angle between 0 and -180 degrees.

largePositive : SweptAngle

Construct a counterclockwise arc with a swept angle between 180 and 360 degrees.

largeNegative : SweptAngle

Construct a clockwise arc with a swept angle between -180 and -360 degrees.

ianmackenzie/elm-geometry/4.0.0

SweptAngle

Modules