private float sweep(float tan1X,float tan1Y,float tan2X,float tan2Y){
  final float minorSweep=(float)Math.toDegrees(2 * (Math.asin(.5 * Geometry.distance(tan1X,tan1Y,tan2X,tan2Y) / mScaledTouchSlop)));
  return 360 - minorSweep;
}

private float sweep ( float tan1X , float tan1Y , float tan2X , float tan2Y ) { final float minorSweep = ( float ) Math . toDegrees ( 2 * ( Math . asin ( .5 * Geometry . distance ( tan1X , tan1Y , tan2X , tan2Y ) / mScaledTouchSlop ) ) ) ; return 360 - minorSweep ; }
find the angle in degrees between two tangent points
