pinch/zoom for Android Java

This humble code interpretes the distance between two pointers as the ratio.

	static final int NumberOfMyPointers = 2;
	static final float minimumDistance2object = 0.1f;
	static final float maximumDistance2object = 3.0f;
	static final float MaxRatio2Screen = 5.0f;
//////////////////////////////////////////////
    	private float pointerCoord_X[];
    	private float pointerCoord_Y[];
    	private float pointersDistance;
    	private float pointersDistance_current;
    	private float pointersDistance_origin;
    	private float pointersDistance_delta;
    	private float distance2object;
//////////////////////////////////////////////
        public void resetOrigin(){
        	float dX, dY;
		dX = pointerCoord_X[1] - pointerCoord_X[0];
		dY = pointerCoord_Y[1] - pointerCoord_Y[0];
		pointersDistance_origin = (float) Math.sqrt((dX*dX)+(dY*dY));        	
        }
        
        @Override
        public void onTouchEvent(MotionEvent me) {
        	// by Android API ref., 
        	// idx = [0, getPointerCount() -1]
        	// id = keep while touched, reset on down to minimum empty.
        	// The bottom line is, all you should refer is idx 0 and 1. Id is useless for zoom and pinch.
        	int i, j;
        	float dX, dY, d;
        	int ma = me.getActionMasked();
        	int me_num_pointers = me.getPointerCount();
    		switch(ma){
    		case(MotionEvent.ACTION_POINTER_DOWN):
    			if (me_num_pointers < NumberOfMyPointers) break;
    			for (i=0;i<NumberOfMyPointers;i++){
    				pointerCoord_X[i] = me.getX(i);
    				pointerCoord_Y[i] = me.getY(i);
    			}
    			resetOrigin();
   			pointersDistance += pointersDistance_delta;
    			break;
    		case(MotionEvent.ACTION_MOVE):
    			if (me_num_pointers < NumberOfMyPointers) break;
    			for (i=0;i<NumberOfMyPointers;i++){
    				pointerCoord_X[i] = me.getX(i);
    				pointerCoord_Y[i] = me.getY(i);
    			}
   			dX = pointerCoord_X[1] - pointerCoord_X[0];
   			dY = pointerCoord_Y[1] - pointerCoord_Y[0];
   			pointersDistance_current = (float) Math.sqrt((dX*dX)+(dY*dY));
   			pointersDistance_delta = pointersDistance_current - pointersDistance_origin; 
   			d = pointersDistance + pointersDistance_delta;
   			if (d < screenWidth){
				resetOrigin();
				pointersDistance_delta =  screenWidth  - pointersDistance;
   				d = screenWidth;
   			}else if (d > MaxRatio2Screen*screenWidth){ 
				resetOrigin();
				pointersDistance_delta = 5.0f*w - pointersDistance;
				d = MaxRatio2Screen*screenWidth;
    			}
   			distance2object = ((float)screenWidth)/d;
    			break;
        	default:
        		break;
            }
            super.onTouchEvent(me);
        }