Use a PathFigure object to store ArcSegment objects and other segments.
An elliptical arc is defined by its start and end points, x- and y-radius, x-axis rotation factor, a value indicating whether the arc should be greater than 180 degrees, and a value describing the direction in which the arc is drawn. The ArcSegment class does not contain a property for the starting point of the arc; it only defines the destination point of the arc it represents. The beginning point of the arc is the current point of the PathFigure to which the ArcSegment is added.
The following illustrations demonstrate the different end point, Size, and RotationAngle settings.
IsLargeArc and SweepDirection
For most arcs of a particular position, size, and rotation, there are four different arcs that can be drawn; the IsLargeArc and SweepDirection properties indicate which arc to use.
Of the four candidate arc sweeps, two represent large arcs with sweeps of 180 degrees or greater, and two represent smaller arcs with sweeps 180 degrees or less. If IsLargeArc is true, then one of the two larger arc sweeps is chosen; otherwise, if IsLargeArc is false, one of the smaller arc sweeps is chosen. The remaining two arc candidates are each drawn in a different direction: Counterclockwise or Clockwise. The SweepDirection property specifies which one to use.
The following illustrations show different IsLargeArc and SweepDirection settings.
ArcSegment objects with different IsLargeArc settings
ArcSegment objects with different SweepDirection settings