import com.imsl.chart.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Stack;
import javax.swing.JMenu;
import javax.swing.JMenuItem;

public class SampleZoom extends JFrameChart
                implements MouseListener, MouseMotionListener, ActionListener {
    private javax.swing.JPanel panel;
    private AxisXY  axis;
    private int     xFirst, yFirst;
    private int     xLast, yLast;
    private Stack   stack;
    
    public SampleZoom() {
        // create a scatter plot with some random points
        Chart chart = getChart();
        axis = new AxisXY(chart);
        int n = 1000;
        double x[] = new double[n];
        double y[] = new double[n];
        for (int k = 0;  k < n;  k++) {
            x[k] = 10.*Math.random();
            y[k] = 10.*Math.random();
        }
        Data data = new Data(axis, x, y);
        data.setDataType(Data.DATA_TYPE_MARKER);
        
        // add menu "Zoom" menu
        JMenu jMenuZoom = new JMenu("Zoom");
        jMenuZoom.setMnemonic('Z');
        addMenuItem(jMenuZoom, "Out");
        addMenuItem(jMenuZoom, "Restore");
        getJMenuBar().add(jMenuZoom);
        
        // save x-axis and y-axis Window attributes on this stack.
        // they are used to zoom out one level.
        stack = new Stack();
        
        // listen for mouse press events
        panel = getPanel();
        panel.addMouseListener(this);
    }
    
    /**
     *  Add a menu item
     */
    private void addMenuItem(JMenu jMenuZoom, String title) {
        JMenuItem jMenuItem = new JMenuItem(title);
        jMenuItem.setActionCommand(title);
        jMenuItem.setMnemonic(title.charAt(0));
        jMenuZoom.add(jMenuItem);
        jMenuItem.addActionListener(this);
    }
    
    /**
     *  A mouse press starts the zoom
     *  Record location of this point and listen for drag (motion) events.
     */
    public void mousePressed(MouseEvent event) {
        xFirst = xLast = event.getX();
        yFirst = yLast = event.getY();
        panel.addMouseMotionListener(this);
    }
    
    /**
     *  A mouse release ends the zoom.
     *  Stop listening for drag events and update the
     *  Window attribute in the x and y axes.
     */
    public void mouseReleased(MouseEvent event) {
        panel.removeMouseMotionListener(this);
        
        // ignore degenerate zooms
        if (xFirst==xLast || yFirst==yLast) {
            repaint();
            return;
        }
        
        // get window and convert to user coordinates
        double windowX[] = (double[])axis.getAxisX().getWindow();
        double windowY[] = (double[])axis.getAxisY().getWindow();
        
        // save the windows on the stack (for zoom out option)
        stack.add(windowX);
        stack.add(windowY);
        
        // get user coordinate of left-upper corner of the box
        // limit it to stay inside current window
        double boxLU[] = new double[2];
        int x = Math.min(xFirst, xLast);
        int y = Math.min(yFirst, yLast);
        axis.mapDeviceToUser(x, y, boxLU);

        // get user coordinate of right-lower corner of the box
        // limit it to stay inside current window
        double boxRL[] = new double[2];
        x = Math.max(xFirst, xLast);
        y = Math.max(yFirst, yLast);
        axis.mapDeviceToUser(x, y, boxRL);
        
        // set axis window to range of rubber-band box
        // and disable autoscale to force use of window settings
        axis.setAutoscaleInput(ChartNode.AUTOSCALE_OFF);
        double xa = Math.max(windowX[0], boxLU[0]);
        double xb = Math.min(windowX[1], boxRL[0]);
        double ya = Math.max(windowY[0], boxRL[1]);
        double yb = Math.min(windowY[1], boxLU[1]);
        axis.getAxisX().setWindow(xa, xb);
        axis.getAxisY().setWindow(ya, yb);
        
        // force redraw of the chart
        repaint();
    }
    
    /**
     *  A drag event continues the zoom.
     *  Erase the old rubber-band box and draw a new one.
     *  Also keep track of the location of this event.
     */
    public void mouseDragged(MouseEvent event) {
        // erase previous rectangle
        Graphics g = panel.getGraphics();
        g.setXORMode(Color.cyan);  // complement of drawing color red
        drawBox(g);
        
        // draw new rectangle
        xLast = event.getX();
        yLast = event.getY();
        g.setPaintMode();
        g.setColor(Color.red);
        drawBox(g);
    }
    
    public void mouseMoved(MouseEvent event) {}
    public void mouseEntered(MouseEvent event) {}
    public void mouseClicked(MouseEvent event) {}
    public void mouseExited(MouseEvent event) {}
    
    /**
     *  Draw a box with (xFirst,yFirst) and (xLast,yLast) as its corners.
     */
    private void drawBox(Graphics g) {
        int x = Math.min(xFirst, xLast);
        int y = Math.min(yFirst, yLast);
        int w = Math.abs(xLast - xFirst);
        int h = Math.abs(yLast - yFirst);
        g.drawRect(x, y, w, h);
    }
    
    /**
     *  Handle menu item events.
     *  Command "Out" zooms out one level.
     *  Command "Restore" undoes all zooms.
     */ 
    public void actionPerformed(ActionEvent actionEvent) {
        String command = actionEvent.getActionCommand();
        if (command.equals("Out")) {
            try {
                // zoom out by restoring window settings from the stack
                axis.getAxisY().setWindow((double[])stack.pop());
                axis.getAxisX().setWindow((double[])stack.pop());
            } catch (java.util.EmptyStackException e) {
                // no more levels to zoom out
                // restore original setting by turning on autoscale
                axis.setAutoscaleInput(ChartNode.AUTOSCALE_DATA);
            }
        } else if (command.equals("Restore")) {
            // restore original setting by turning on autoscale an empty stack
            axis.setAutoscaleInput(ChartNode.AUTOSCALE_DATA);
            stack.empty();
        }
        // force redraw of the chart
        repaint();
    }
    
    public static void main(String argv[]) {
        new SampleZoom().setVisible(true);
    }  
}