printpreviewdialog.java

物业管理系统

package wuYeGuanLi;

import java.awt.event.*;
import java.awt.*;
import java.awt.print.*;
import javax.swing.*;
//import wf.common.SystemProperties;
import java.awt.geom.*;

public class PrintPreviewDialog
    extends JDialog
    implements ActionListener {
  private JButton nextButton = new JButton("Next");
  private JButton previousButton = new JButton("Previous");
  private JButton closeButton = new JButton("Close");
  private JPanel buttonPanel = new JPanel();
  private PreviewCanvas canvas;

  public PrintPreviewDialog(Frame parent, String title, boolean modal,
                            PrintTest pt, String str) {
    super(parent, title, modal);
    canvas = new PreviewCanvas(pt, str);
    setLayout();
  }

  private void setLayout() {
    this.getContentPane().setLayout(new BorderLayout());
    this.getContentPane().add(canvas, BorderLayout.CENTER);

    nextButton.setMnemonic('N');
    nextButton.addActionListener(this);
    buttonPanel.add(nextButton);
    previousButton.setMnemonic('N');
    previousButton.addActionListener(this);
    buttonPanel.add(previousButton);
    closeButton.setMnemonic('N');
    closeButton.addActionListener(this);
    buttonPanel.add(closeButton);
    this.getContentPane().add(buttonPanel, BorderLayout.SOUTH);
    Dimension screen = Toolkit.getDefaultToolkit().getScreenSize();
    this.setBounds( (int) ( (screen.width - 400) / 2),
                   (int) ( (screen.height - 400) / 2), 400,
                   400);
  }

  public void actionPerformed(ActionEvent evt) {
    Object src = evt.getSource();
    if (src == nextButton) {
      nextAction();
    }
    else if (src == previousButton) {
      previousAction();
    }
    else if (src == closeButton) {
      closeAction();
    }
  }

  private void closeAction() {
    this.setVisible(false);
    this.dispose();
  }

  private void nextAction() {
    canvas.viewPage(1);
  }

  private void previousAction() {
    canvas.viewPage( -1);
  }

  class PreviewCanvas
      extends JPanel {
    private String printStr;
    private int currentPage = 0;
    private PrintTest preview;

    public PreviewCanvas(PrintTest pt, String str) {
      printStr = str;
      preview = pt;
    }

    public void paintComponent(Graphics g) {
      super.paintComponent(g);
      Graphics2D g2 = (Graphics2D) g;
      PageFormat pf = PrinterJob.getPrinterJob().defaultPage();

      double xoff;
      double yoff;
      double scale;
      double px = pf.getWidth();
      double py = pf.getHeight();
      double sx = getWidth() - 1;
      double sy = getHeight() - 1;
      if (px / py < sx / sy) {
        scale = sy / py;
        xoff = 0.5 * (sx - scale * px);
        yoff = 0;
      }
      else {
        scale = sx / px;
        xoff = 0;
        yoff = 0.5 * (sy - scale * py);
      }
      g2.translate( (float) xoff, (float) yoff);
      g2.scale( (float) scale, (float) scale);

      Rectangle2D page = new Rectangle2D.Double(0, 0, px, py);
      g2.setPaint(Color.white);
      g2.fill(page);
      g2.setPaint(Color.black);
      g2.draw(page);

      try {
        preview.print(g2, pf, currentPage);
      }
      catch (PrinterException pe) {
        //g2.draw(new Line2D.Double(0, 0, px, py));
        //g2.draw(new Line2D.Double(0, px, 0, py));
      }
    }

    public void viewPage(int pos) {
      int newPage = currentPage + pos;
      if (0 <= newPage && newPage < preview.getPagesCount(printStr)) {
        currentPage = newPage;
        repaint();
      }
    }
  }
}