Graphics 2D paintComponent Ruler

// PRINTING RULER
        int x1, y1, x2, y2; int block = 40;
        Line2D line;

        // Horizontal
        x1 = y1 = 0;
        x2 = 0; y2 = 5;
        int center = 0;
        for (int i = 0; i < 40; i++)
        {
            line = new Line2D.Double(x1, y1, x2, y2);
            g2.draw(line);
            if (i < 10)
                center = x1 - 3;
            else
                center = x1 - 6;
            g2.drawString(i+"", center, 20);
            x1 += block;
            x2 += block;
        }

        // Vertical
        x1 = y1 = 0;
        x2 = 5; y2 = 0;
        for (int i = 0; i < 20; i++)
        {
            line = new Line2D.Double(x1, y1, x2, y2);
            g2.draw(line);
            g2.drawString(i+"", 8, y1 + 5);
            y1 += block;
            y2 += block;
        }