package components;import java.awt.*;import javax.swing.*;/* Rule.java is used by ScrollDemo.java. */public class Rule extends JComponent {    public static final int INCH = Toolkit.getDefaultToolkit().            getScreenResolution();    public static final int HORIZONTAL = 0;    public static final int VERTICAL = 1;    public static final int SIZE = 35;    public int orientation;    public boolean isMetric;    private int increment;    private int units;    public Rule(int o, boolean m) {        orientation = o;        isMetric = m;        setIncrementAndUnits();    }    public void setIsMetric(boolean isMetric) {        this.isMetric = isMetric;        setIncrementAndUnits();        repaint();    }    private void setIncrementAndUnits() {        if (isMetric) {            units = (int)((double)INCH / (double)2.54); // dots per centimeter            increment = units;        } else {            units = INCH;            increment = units / 2;        }    }    public boolean isMetric() {        return this.isMetric;    }    public int getIncrement() {        return increment;    }    public void setPreferredHeight(int ph) {        setPreferredSize(new Dimension(SIZE, ph));    }    public void setPreferredWidth(int pw) {        setPreferredSize(new Dimension(pw, SIZE));    }    protected void paintComponent(Graphics g) {        Rectangle drawHere = g.getClipBounds();        // Fill clipping area with dirty brown/orange.        g.setColor(new Color(230, 163, 4));        g.fillRect(drawHere.x, drawHere.y, drawHere.width, drawHere.height);        // Do the ruler labels in a small font that's black.        g.setFont(new Font("SansSerif", Font.PLAIN, 10));        g.setColor(Color.black);        // Some vars we need.        int end = 0;        int start = 0;        int tickLength = 0;        String text = null;        // Use clipping bounds to calculate first and last tick locations.        if (orientation == HORIZONTAL) {            start = (drawHere.x / increment) * increment;            end = (((drawHere.x + drawHere.width) / increment) + 1)                  * increment;        } else {            start = (drawHere.y / increment) * increment;            end = (((drawHere.y + drawHere.height) / increment) + 1)                  * increment;        }        // Make a special case of 0 to display the number        // within the rule and draw a units label.        if (start == 0) {            text = Integer.toString(0) + (isMetric ? " cm" : " in");            tickLength = 10;            if (orientation == HORIZONTAL) {                g.drawLine(0, SIZE-1, 0, SIZE-tickLength-1);                g.drawString(text, 2, 21);            } else {                g.drawLine(SIZE-1, 0, SIZE-tickLength-1, 0);                g.drawString(text, 9, 10);            }            text = null;            start = increment;        }        // ticks and labels        for (int i = start; i < end; i += increment) {            if (i % units == 0)  {                tickLength = 10;                text = Integer.toString(i/units);            } else {                tickLength = 7;                text = null;            }            if (tickLength != 0) {                if (orientation == HORIZONTAL) {                    g.drawLine(i, SIZE-1, i, SIZE-tickLength-1);                    if (text != null)                        g.drawString(text, i-3, 21);                } else {                    g.drawLine(SIZE-1, i, SIZE-tickLength-1, i);                    if (text != null)                        g.drawString(text, 9, i+3);                }            }        }    }}