printabletextarea.java

JAVA程序设计与实践.rar

/*
 * 文件名:PrintableTextArea.java
 * 说  明:文本编辑框,实现了Printable接口,可打印文字
 */
// 导入相关包
import java.awt.*;
import java.io.*;
import java.awt.print.*;

import javax.swing.*;
import javax.swing.text.*;

// 主类PrintableTextArea
class PrintableTextArea extends JTextArea
                        implements Printable {
  // 属性声明
  String str;
  Font font;
  PrinterJob pj;
  PageFormat defaultFormat;
  int visiblePageWidth = 0, visiblePageHeight = 0;
  final static int PageX = 10, PageY = 10;
  
  // 构造方法
  PrintableTextArea(int rows, int columns) {
    super(rows, columns);
  }
  
  // 打印方法
  public void printIt(String str, Font font) {
    this.str = str;
    this.font = font;
    pj = PrinterJob.getPrinterJob();
    defaultFormat = pj.defaultPage();
    pj.setPrintable(this, defaultFormat);
    visiblePageWidth = (int)defaultFormat.getImageableWidth();
    visiblePageHeight = (int)defaultFormat.getImageableHeight();
    if(pj.printDialog()) {
      try {
        pj.print();
      } catch(PrinterException e) {
      }
    }
  }
  // print方法
  public int print(Graphics g, PageFormat pf, int page) throws PrinterException {
    if(page >= 1)
      return Printable.NO_SUCH_PAGE;
    Graphics2D g2 = (Graphics2D) g;
    g2.translate((int)pf.getImageableX(), (int)pf.getImageableY());
    g2.setFont(font);
    int fontHeight = 0, fontStringWidth = 0;
    int line = 0;
    String s = null;
    FontMetrics fm = getFontMetrics(font);
    fontHeight = fm.getHeight();
    try{
      DataOutputStream osw = new DataOutputStream(new FileOutputStream("$temp.$$p"));
      osw.writeBytes(str);
      osw.close();
    } catch(IOException e) {
    }
    try {
      BufferedReader br = new BufferedReader(new FileReader("$temp.$$p"));
      s = br.readLine();
      while(s != null) {
        if(s.length() == 0)
          g2.drawString(" ", PageX, PageY + fontHeight*(line++));
        else {
          //g2.drawString(s, PageX, PageY + fontHeight*(line++));
          fontStringWidth = fm.stringWidth(s);
          if(fontStringWidth > visiblePageWidth) {
            String s1, s2;
            int goBack = 0;
            while( fm.stringWidth(s1 = s.substring(0, s.length() - goBack)) >
                   visiblePageWidth) {
              goBack++;
            }
            s1 = s.substring(0, s.length() - goBack);
            s2 = s.substring(s.length() - goBack - 1);
            g2.drawString(s1, PageX, PageY + fontHeight*(line++));
            g2.drawString(s2, PageX, PageY + fontHeight*(line++));
          }
          else {
            g2.drawString(s, PageX, PageY + fontHeight*(line++));
          }
        }
        s = br.readLine();
      }
      br.close();
    } catch(IOException e) {
    }
    return Printable.PAGE_EXISTS;
  }

}

/* other usefull functions
PageFormat defaultFormat = pj.defaultPage();
defaultFormat.getImageableX();
defaultFormat.getImageableY();
defaultFormat.getWidth();
defaultFormat.getHeight();
defaultFormat.getImageableWidth();
defaultFormat.getImageableHeight();


PageFormat selectedFormat = pj.pageDialog(defaultFormat);
selectFormat.getImageableX();
selectFormat.getImageableY();
selectFormat.getWidth();
selectFormat.getHeight();
selectFormat.getImageableWidth();
selectFormat.getImageableHeight();

stringWidth(String str)

*/