BCGControlBar Pro for MFC
void CBCGPDiagramCustomShape::AddArc ( const CBCGPPoint pt,
const CBCGPSize  szRadius,
BOOL  bIsClockwise = TRUE,
BOOL  bIsLargeArc = FALSE,
double  dblRotationAngle = 0. 

Adds an arc segment to the shape geometry.

ptThe arc end point.
szRadiusThe arc radius.
bIsClockwiseTRUE if arc is clockwise.
bIsLargeArcTRUE if the arc is large (more than 180 degrees).
dblRotationAngle(optional) The arc rotation angle.