private double getTouchDegrees(float xPos, float yPos) {
		float x = xPos - mTranslateX;
		float y = yPos - mTranslateY;
		//invert the x-coord if we are rotating anti-clockwise
		x= (mClockwise) ? x:-x;
		// convert to arc Angle
		double angle = Math.toDegrees(Math.atan2(y, x) + (Math.PI / 2)
				- Math.toRadians(mRotation));
		if (angle < 0) {
			angle = 360 + angle;
		}
		angle -= mStartAngle;
		return angle;
	}
Notification that the user has finished a touch gesture. Clients may
want to use this to re-enable advancing the seekarc.

@param seekArc
           The SeekArc in which the touch gesture began
SeekArc_library/src/com/triggertrap/seekarc/SeekArc.java