Question

是否可以将JPanel或任何其他组件发送到打印机？或者我是否必须手动将所有绘图实现到图形对象？

我尝试使用JPanel的Print *功能打印到图形对象，但打印的页面是空白的。

Answer 1

查看Java打印API and tutorial以及JComponent.print（Graphics）。

这是一个基本课程，它将打印任何适合1页的组件（我不能因此而受到赞誉，我从Marty Hall's tutorial得到了代码）：

import java.awt.*;
import java.awt.print.*;
import javax.swing.*;

/**
 * Generic component printer.  This object allows any AWT or Swing component  (or DCT system)
 * to be printed by performing it pre and post print responsibilities.
 * <p>
 * When printing components, the role of the print method is nothing more than to scale the Graphics, turn off double
 * buffering, and call paint.  There is no particular reason to put that print method in the component being printed.  A
 * better approach is to build a generic printComponent method to which you simply pass the component you want printed.
 * <p>
 * With Swing, almost all components have double buffering turned on by default. In general, this is a great benefit,
 * making for convenient and efficient painting. However, in the specific case of printing, it can is a huge problem.
 * First, since printing components relies on scaling the coordinate system and then simply calling the component's
 * paint method, if double buffering is enabled printing amounts to little more than scaling up the buffer (off-screen
 * image) which results in ugly low-resolution printing like you already had available. Secondly, sending these huge
 * buffers to the printer results in huge print spooler files which take a very long time to print. Consequently this
 * object globally turns off double buffering before printing and turns it back on afterwards.
 * <p>
 * Threading Design : [x] Single Threaded  [ ] Threadsafe  [ ] Immutable  [ ] Isolated
 */

public class ComponentPrinter
extends Object
implements Printable
{

// *****************************************************************************
// INSTANCE PROPERTIES
// *****************************************************************************

private Component                       component;                              // the component to print

// *****************************************************************************
// INSTANCE CREATE/DELETE
// *****************************************************************************

public ComponentPrinter(Component com) {
    component=com;
    }

// *****************************************************************************
// INSTANCE METHODS
// *****************************************************************************

public void print() throws PrinterException {
    PrinterJob                          printJob=PrinterJob.getPrinterJob();

    printJob.setPrintable(this);
    if(printJob.printDialog()) {
        printJob.print();
        }
    }

public int print(Graphics gc, PageFormat pageFormat, int pageIndex) {
    if(pageIndex>0) {
        return NO_SUCH_PAGE;
        }

    RepaintManager                      mgr=RepaintManager.currentManager(component);
    Graphics2D                          g2d=(Graphics2D)gc;

    g2d.translate(pageFormat.getImageableX(),pageFormat.getImageableY());
    mgr.setDoubleBufferingEnabled(false);                                       // only for swing components
    component.paint(g2d);
    mgr.setDoubleBufferingEnabled(true);                                        // only for swing components
    return PAGE_EXISTS;
    }

// *****************************************************************************
// STATIC METHODS
// *****************************************************************************

static public void printComponent(Component com) throws PrinterException {
    new ComponentPrinter(com).print();
    }

} // END PUBLIC CLASS

Answer 2

This tutorial提及翻译Graphics对象。你试过了吗？

Answer 3

请考虑this answer将Component打印到多个页面：

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.print.*;

import javax.swing.RepaintManager;

public class PrintMultiPageUtil implements Printable, Pageable {
    private Component componentToBePrinted;
    private PageFormat format;
    private int numPages;

    public PrintMultiPageUtil(Component componentToBePrinted) {
        this.componentToBePrinted = componentToBePrinted;

        // get total space from component  
        Dimension totalSpace = this.componentToBePrinted.getPreferredSize();

        // calculate for DIN A4
        format = PrinterJob.getPrinterJob().defaultPage();
        numPages = (int) Math.ceil(totalSpace .height/format.getImageableHeight());
    }

    public void print() {
        PrinterJob printJob = PrinterJob.getPrinterJob();

        // show page-dialog with default DIN A4
        format = printJob.pageDialog(printJob.defaultPage());

        printJob.setPrintable(this);
        printJob.setPageable(this);

        if (printJob.printDialog())
            try {
                printJob.print();
            } catch(PrinterException pe) {
                System.out.println("Error printing: " + pe);
            }
    }

    public int print(Graphics g, PageFormat pageFormat, int pageIndex) {
        if ((pageIndex < 0) | (pageIndex >= numPages)) {
            return(NO_SUCH_PAGE);
        } else {
            Graphics2D g2d = (Graphics2D)g;
            g2d.translate(pageFormat.getImageableX(), pageFormat.getImageableY() - pageIndex * pageFormat.getImageableHeight());
            disableDoubleBuffering(componentToBePrinted);
            componentToBePrinted.paint(g2d);
            enableDoubleBuffering(componentToBePrinted);
            return(PAGE_EXISTS);
        }
    }

    public static void disableDoubleBuffering(Component c) {
        RepaintManager currentManager = RepaintManager.currentManager(c);
        currentManager.setDoubleBufferingEnabled(false);
    }

    public static void enableDoubleBuffering(Component c) {
        RepaintManager currentManager = RepaintManager.currentManager(c);
        currentManager.setDoubleBufferingEnabled(true);
    }

    @Override
    public int getNumberOfPages() {
        // TODO Auto-generated method stub
        return numPages;
    }

    @Override
    public PageFormat getPageFormat(int arg0) throws IndexOutOfBoundsException {
        return format;
    }

    @Override
    public Printable getPrintable(int arg0) throws IndexOutOfBoundsException {
        // TODO Auto-generated method stub
        return this;
    }
}

将JPanel发送到打印机

3 个答案: