Rotate point from a given center in Flex - apache-flex

Question

I'm trying to rotate a point in my Canvas from a given point (center). In my MouseDown handler, I save the point where user click (oldPos), and in my MouseMove handler, I'm doing this:
private function onMouseMove(event:MouseEvent):void
{
// Where the user pointer right now
var endPoint:Point = new Point(event.localX,event.localY);
// Calculate angle in radians from the user pointer
var angle:Number = getLineAngleFromHorizontal(oldPos,endPoint);
var rad:Number = Math.PI * (angle / 180);
// Point which I want to rotate
pTop = new Point(oldPos.x,oldPos.y - 30);
var distance:Number = Point.distance(oldPos,pTop);
// Calculate the translation point from previously distance and angle
var translatePoint:Point = Point.polar(distance, rad);
// New point coordinates (in theory)
pTop.x += translatePoint.x;
pTop.y += translatePoint.y;
// Then, draw the line...
}
Where getLineAngleFromHorizontal is a function that returns the angle formed by a center and a give point:
private function getLineAngleFromHorizontal(p1:Point,p2:Point):Number
{
var RotVecOrigen:Point = new Point((p2.x-p1.x),(p2.y-p1.y));
var ModRot:Number = Math.sqrt((RotVecOrigen.x*RotVecOrigen.x)+(RotVecOrigen.y*RotVecOrigen.y));
var ret:Number;
if(((RotVecOrigen.x < 0) && (RotVecOrigen.y <= 0))||((RotVecOrigen.x >= 0) && (RotVecOrigen.y < 0)))
{
ret = Math.round((180.0*(Math.acos(RotVecOrigen.x/ModRot))/Math.PI));
}else{
ret = Math.round((180.0*(-Math.acos(RotVecOrigen.x/ModRot))/Math.PI));
}
return ret;
}
To see an example, watch the image below:
But I don't know why isn't work. I mean, pTop point isn't move where I want, and I think that my calcs are correct.
Can anybody help me? (maybe someone with Math knowledge)

Answer 1

I'm not entirely sure what you want to accomplish. Do you want your new point to be at an 330 degree offset from your center point?
If you want to move your point 330 degrees, use this:
function directionalDistance($start:Point, $direction:Number, $distance:Number, $zeroDegreesUp:Boolean = false):Point{
if($zeroDegreesUp) $direction = ( $direction + 270)%360;
var x:Number = Math.cos($direction * Math.PI / 180) * $distance;
var y:Number = Math.sin($direction * Math.PI / 180) * $distance;
return new Point($start.x +x, $start.y + y);
}
//
var newPoint:Point = directionalDistance(new Point(event.localX,event.localY), 330, 50, true);