//---------------------------------------------------------------------------
void __fastcall getLineData(double *OutLength, double *OutAngle, int x1, int y1, int x2, int y2)
{
int x_ord, y_ord;
double hypo, angle;
y_ord = y1 - y2;
x_ord = x2 - x1;
hypo = sqrt(y_ord*y_ord + x_ord*x_ord);
if (hypo == 0)
    {
    *OutAngle = 0;
    *OutLength = 0;
    return;
    }
// calculate angle as it's in the first quadrant
angle = asin((double)abs(y_ord) / hypo);
// let's check the quadrant.
// first or second quadrant?
if (y_ord >= 0)
    {
    if (x_ord < 0)
       angle = M_PI - angle;
    }
// third or fourth quadrant?
else
    {
    angle = - angle;
    if (x_ord < 0)
        angle = -M_PI - angle;
    }
*OutAngle = angle;
*OutLength = hypo;
//NOTE: output angle is in radians.
//To convert radians to degrees: angle = 180.0*angle/M_PI;
}

//------------------------------------------------------------------------------------------------
// Rotate array of points by some angle (in radians)
//------------------------------------------------------------------------------------------------
void __fastcall rotatePoints(TPoint *points, int points_number, TPoint *origin, double angle)
{
int ox, oy, x1, y1;
ox = origin->x;
oy = origin->y;
for (int i = 0; i < points_number; i++)
    {
    x1 = points[i].x;
    y1 = points[i].y;
    points[i].x = fast_ftol(ox + (x1 - ox)*cos(angle) - (y1 - oy)*sin(angle));
    points[i].y = fast_ftol(oy + (x1 - ox)*sin(angle) + (y1 - oy)*cos(angle));
    }
//NOTE: replace fast_ftol function with rounding function at your choice.
}
//------------------------------------------------------------------------------------------------
// Translate array of points given some radius vector (x,y) 
//------------------------------------------------------------------------------------------------
void __fastcall translatePoints(TPoint *points, int points_number, TPoint *trans)
{
for (int i = 0; i < points_number; i++)
    {
    points[i].x += trans->x;
    points[i].y += trans->y;
    }
}
//---------------------------------------------------------------------------
// Reflect array of points around arbitrarty line (given origin and angle)
//---------------------------------------------------------------------------
void __fastcall reflectPoints(TPoint *points, int points_number, TPoint *origin, double angle)
{
int ox, oy, x1, y1;
ox = origin->x;
oy = origin->y;
for (int i = 0; i < points_number; i++)
    {
    x1 = points[i].x;
    y1 = points[i].y;
    points[i].x = fast_ftol(ox + (x1 - ox)*cos(2.0*angle) + (y1 - oy)*sin(2.0*angle));
    points[i].y = fast_ftol(oy + (x1 - ox)*sin(2.0*angle) - (y1 - oy)*cos(2.0*angle));
    }
//NOTE: replace fast_ftol function with rounding function at your choice.
}

// third or fourth quadrant?
else
    {
    if (x_ord <= 0)
        angle = M_PI + angle;
    else
        angle = 2.0*M_PI - angle;    
    }