java实现打印的实例
时间:2007-05-29 yycnet.yeah.net yyc译
非常不幸，打印时没有多少事情是可以自动进行的。相反，为完成打印，我们必须经历大量机械的、非OO（面向对象）的步骤。但打印一个图形化的组件时，可能多少有点儿自动化的意思：默认情况下，print()方法会调用paint()来完成自己的工作。大多数时候这都已经足够了，但假如还想做一些特别的事情，就必须知道页面的几何尺寸。下面这个例子同时演示了文字和图形的打印，以及打印图形时可以采取的不同方法。此外，它也对打印支持进行了测试：
//: PrintDemo.java
// Printing with Java 1.1
import java.awt.*;
import java.awt.event.*;
public class PrintDemo extends Frame {
Button
printText = new Button("Print Text"),
printGraphics = new Button("Print Graphics");
TextField ringNum = new TextField(3);
Choice faces = new Choice();
Graphics g = null;
Plot plot = new Plot3(); // Try different plots
Toolkit tk = Toolkit.getDefaultToolkit();
public PrintDemo() {
ringNum.setText("3");
ringNum.addTextListener(new RingL());
Panel p = new Panel();
p.setLayout(new FlowLayout());
printText.addActionListener(new TBL());
p.add(printText);
p.add(new Label("Font:"));
p.add(faces);
printGraphics.addActionListener(new GBL());
p.add(printGraphics);
p.add(new Label("Rings:"));
p.add(ringNum);
setLayout(new BorderLayout());
add(p, BorderLayout.NORTH);
add(plot, BorderLayout.CENTER);
String[] fontList = tk.getFontList();
for(int i = 0; i < fontList.length; i++)
faces.add(fontList[i]);
faces.select("Serif");
}
class PrintData {
public PrintJob pj;
public int pageWidth, pageHeight;
PrintData(String jobName) {
pj = getToolkit().getPrintJob(
PrintDemo.this, jobName, null);
if(pj != null) {
pageWidth = pj.getPageDimension().width;
pageHeight= pj.getPageDimension().height;
g = pj.getGraphics();
}
}
void end() { pj.end(); }
}
class ChangeFont {
private int stringHeight;
ChangeFont(String face, int style,int point){
if(g != null) {
g.setFont(new Font(face, style, point));
stringHeight =
g.getFontMetrics().getHeight();
}
}
int stringWidth(String s) {
return g.getFontMetrics().stringWidth(s);
}
int stringHeight() { return stringHeight; }
}
class TBL implements ActionListener {
public void actionPerformed(ActionEvent e) {
PrintData pd =
new PrintData("Print Text Test");
// Null means print job canceled:
if(pd == null) return;
String s = "PrintDemo";
ChangeFont cf = new ChangeFont(
faces.getSelectedItem(), Font.ITALIC,72);
g.drawString(s,
(pd.pageWidth - cf.stringWidth(s)) / 2,
(pd.pageHeight - cf.stringHeight()) / 3);
s = "A smaller point size";
cf = new ChangeFont(
faces.getSelectedItem(), Font.BOLD, 48);
g.drawStri |
