发送一个JPanel到打印机

Question

是否可以直接向打印机发送JPanel或任何其他组件？还是我必须手动执行所有绘图到图形对象？

我试图使用JPanel的Print *函数打印到图形对象，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）。

这是一个基本的类将打印的符合第1页上的任何组件（我不能把信贷对于这一点，我从Marty Hall's tutorial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提到翻译Graphics对象。你尝试过吗？