ScreenToGif.Pages.Crop.pictureCrop_MouseUp C# (CSharp) Méthode

        private void pictureCrop_MouseUp(object sender, MouseEventArgs e)
        {
            //Quite a work with this thing huh...

            if (e.Button != MouseButtons.Left)
                return;

            if (e.X > _posX && e.Y > _posY)
            {
                _width = Math.Abs(e.X - _posX);
                _height = Math.Abs(e.Y - _posY);
            }
            else if (e.X < _posX && e.Y < _posY)
            {
                _width = Math.Abs(_posX - e.X);
                _height = Math.Abs(_posY - e.Y);

                _posX = e.X;
                _posY = e.Y;
            }
            else if (e.X < _posX && e.Y > _posY) // top right to bottom left
            {
                _width = Math.Abs(_posX - e.X);
                _height = Math.Abs(_posY - e.Y);

                _posX = e.X;
            }
            else if (e.X > _posX && e.Y < _posY)  //bottom left to top right
            {
                _width = Math.Abs(_posX - e.X);
                _height = Math.Abs(_posY - e.Y);

                _posY = e.Y;
            }
            else if (e.X == _posX && e.Y == _posY)
            {
                this.Text = Resources.Title_CropNoSelection;
                tbHeight.Text = "0"; 
                tbWidth.Text = "0";
                _width = 0;
                _height = 0;
                _g.DrawImage(_bitmap, 0, 0);
                return;
            }

            if (_posX + _width > pictureCrop.Size.Width)
                _width = pictureCrop.Size.Width - _posX;

            if (_posY + _height > pictureCrop.Size.Height)
                _height = pictureCrop.Size.Height - _posY;

            if (_posX < 0)
            {
                _width = _width - Math.Abs(_posX);
                _posX = 0;
            }

            if (_posY < 0)
            {
                _height = _height - Math.Abs(_posY);
                _posY = 0;
            }

            this.Text = Resources.Title_Crop;
            tbWidth.Text = _width.ToString();
            tbHeight.Text = _height.ToString();

            _g.DrawImage(_bitmap, 0, 0);
            Rectangle = new Rectangle(_posX, _posY, _width, _height);
            _g = pictureCrop.CreateGraphics();
            _g.DrawRectangle(_pen, Rectangle);
        }