ArcTo
status_t ArcTo(float rx, float ry,
s.ArcTo(rect.Width()/4, rect.Height()/4, 0, false, true, rect.RightTop());
shape.ArcTo(arcRX, arcRY, 45, true, true, BPoint(100, 20));
shape.ArcTo(arcRX, arcRY, 45, false, true, BPoint(100, 20));
shape.ArcTo(arcRX, arcRY, 45, true, false, BPoint(100, 20));
shape.ArcTo(arcRX, arcRY, 45, false, false, BPoint(100, 20));