DrawInfiniteLine

#region GetPoints Methods

        private Tuple<Point, Point> GetPointsInfLine(int x1, int y1, int x2, int y2)
        {
            return GetPointsInfLine(new Point(x1, y1), new Point(x2, y2));
        }

        private Tuple<Point, Point> GetPointsInfLine(Point p1, Point p2)
        {
            var a = p1.Y - p2.Y;
            var b = p2.X - p1.X;
            var c = p1.X * p2.Y - p1.Y * p2.X;

            return GetPointsInfLine(a, b, c);
        }

        private Tuple<Point, Point> GetPointsInfLine(int a, int b, int c)
        {
            var height = picture.Height;
            var width = picture.Width;
            var centerX = picture.Width / 2;
            var centerY = picture.Height / 2;

            if (b == 0)
            {
                return new Tuple<Point, Point>(new Point(centerX + (int) (-c * scale / a), 0),
                    new Point(centerX + (int) (-c * scale / a), height));
            }

            if (a == 0)
            {
                return new Tuple<Point, Point>(new Point(0, centerY - (int) (-c * scale / b)),
                    new Point(width, centerY - (int) (-c * scale / b)));
            }

            var leftX = 0 - centerX;
            var leftY = centerY + (int) ((a * leftX + c * scale) / b);
            leftX = 0;

            var rightX = width - centerX;
            var rightY = centerY + (int) ((a * rightX + c * scale) / b);
            rightX = width;

            return new Tuple<Point, Point>(new Point(leftX, leftY), new Point(rightX, rightY));
        }

        #endregion