Accord.Controls.ManipulatorControl.ManipulatorControl_MouseDown C# (CSharp) Method

        private void ManipulatorControl_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                // get click point relatively to manipulation area's center
                int cX = e.X - areaMargin - areaRadius;
                int cY = e.Y - areaMargin - areaRadius;

                if (isSquareLook)
                {
                    if (
                        (cX <= areaRadius) && (cX >= -areaRadius) &&
                        (cY <= areaRadius) && (cY >= -areaRadius))
                    {
                        tracking = true;
                    }
                }
                else
                {
                    // check if the point is inside of manipulator
                    if (System.Math.Sqrt(cX * cX + cY * cY) <= areaRadius)
                    {
                        tracking = true;
                    }
                }

                if (tracking)
                {
                    manipulatatorX = (float)cX / areaRadius;
                    manipulatatorY = (float)-cY / areaRadius;

                    this.Capture = true;
                    this.Cursor = Cursors.Hand;

                    NotifyClients();
                    // start timer, which is used to notify
                    // about manipulator's position change
                    ticksBeforeNotificiation = -1;
                    timer.Start();
                }
            }
        }