c# - Rotating a circle with mouse with direction -

i rotating circle mouse want there limit on how far circle can rotated. (lets 3 full times). when reaches it's limit can no longer turned in same direction, opposite direction can be. got stopping after max turns i'm trying find direction , every time mouse passes x-axis of circle direction changes because atan2 gives me angle relative x-axis. new mouse position in 1 quadrant , last position in quadrant subtracting these angles doesn't give me want. did explain well? suggestions?

private void helmpb_mousemove(object sender, mouseeventargs e)     {         if ((e.button != mousebuttons.left) || _dontturn) return;         double angle = offsetangle();         point temp = mouseposition;         float degrees = convert.tosingle(angle - _offsetangle);         float diff = _lasthelmangle - degrees;         float absdiff = math.abs(diff) % 360;         if (absdiff > 180) absdiff = 360 - absdiff;         double angle1 = math.atan2(_lasthelmpoint.y, _lasthelmpoint.x);         if (angle1 < 0) angle1 += 2*math.pi;         double angle2 = math.atan2(temp.y, temp.x);         if (angle2 < 0) angle2 += 2*math.pi;         double direction = angle1 - angle2;         direction = direction*(180/math.pi);         _deltahelmturn += convert.tosingle(absdiff);         if (_deltahelmturn >= (_maxhelmturn*360.0))         {             if (direction > 0 && _lasthelmdirection > 0)             {                 _deltahelmturn = convert.tosingle(_maxhelmturn*360.0);                 degrees = convert.tosingle(_maxhelmturn*360.0)%360;             }         }         _lasthelmdirection = direction;         _lasthelmpoint = mouseposition;         _lasthelmangle = convert.tosingle(degrees);         _samehelmrotation = convert.tosingle(degrees);         helmpb.image.dispose();         waterdepthplot.update();         helmpb.image = rotateimage(_originalhelmimage, -degrees);         helmpb.update();     }  private double offsetangle()     {         int helmxmid = helmpb.pointtoscreen(point.empty).x + (helmpb.width / 2);         int helmymid = helmpb.pointtoscreen(point.empty).y + (helmpb.height / 2);         double angle = anglefrompoints(mouseposition, new point(helmxmid, helmymid));         return angle;     }  private double anglefrompoints(point pt1, point pt2)     {         point p = new point(pt1.x - pt2.x, pt1.y - pt2.y);         double alpha;         if (p.y == 0) alpha = p.x > 0 ? 0d : 180d;         else         {             double f = 1d * p.x / (math.sqrt(p.x * p.x + p.y * p.y));             alpha = math.acos(f) * 180d / math.pi;             if (p.y > 0) alpha = 360d - alpha;         }         return alpha;     } 

the direction of rotation between 2 vectors equivalent sign of cross product.

//returns 1 ccw, -1 cw, 0 no change private int direction(point from, point to) {     double cross = (from.x * to.y) - (from.y * to.x);     return math.sign(cross); }