/**
     * @return true if the least distance between point (px,py) and segment (x1,y1) - (x2,y2) is
     *         less then specified tolerance
     */
    private static boolean segmentContainsPoint(int x1, int y1, int x2, int y2, int px, int py,
            int tolerance)
    {
        /*
         * Point should be located inside Rectangle(x1 -+ tolerance, y1 -+ tolerance, x2 +-
         * tolerance, y2 +- tolerance)
         */
        Rectangle lineBounds = Rectangle.SINGLETON;
        lineBounds.setSize(0, 0);
        lineBounds.setLocation(x1, y1);
        lineBounds.union(x2, y2);
        lineBounds.expand(tolerance, tolerance);
        if (!lineBounds.contains(px, py))
        {
            return false;
        }

        /*
         * If this is horizontal, vertical line or dot then the distance between specified point
         * and segment is not more then tolerance (due to the lineBounds check above)
         */
        if (x1 == x2 || y1 == y2)
        {
            return true;
        }

        /*
         * Calculating square distance from specified point to this segment using formula for Dot
         * product of two vectors.
         */
        int v1x = x2 - x1;
        int v1y = y2 - y1;
        int v2x = px - x1;
        int v2y = py - y1;
        int numerator = v2x * v1y - v1x * v2y;
        int denominator = v1x * v1x + v1y * v1y;
        int squareDistance = (int) ((long) numerator * numerator / denominator);
        return squareDistance <= tolerance * tolerance;
    }