java3think in java笔记(111)---打印 (2008-04-24 16:58:28)
标签：杂谈
1 默认情况下，print()方法会调用paint()来完成自己的工作。
2 选择一种字体和大小，决定字符串在页面上存在的位置，并且使用Graphics.drawSrting()方法在页面上画出字符串.必须精确地计算每行字符串在页面上存在的位置并确定字符串不会超出页面底部或者同其它行冲突。
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.drawString(s,
(pd.pageWidth - cf.stringWidth(s)) / 2,
(int)((pd.pageHeight -
cf.stringHeight())/1.5));
g.dispose();
pd.end();
}
}
class GBL implements ActionListener {
public void actionPerformed(ActionEvent e) {
PrintData pd =
new PrintData("Print Graphics Test");
if(pd == null) return;
plot.print(g);
g.dispose();
pd.end();
}
}
class RingL implements TextListener {
public void textValueChanged(TextEvent e) {
int i = 1;
try {
i = Integer.parseInt(ringNum.getText());
} catch(NumberFormatException ex) {
i = 1;
}
plot.rings = i;
plot.repaint();
}
}
public static void main(String[] args) {
Frame pdemo = new PrintDemo();
pdemo.setTitle("Print Demo");
pdemo.addWindowListener(
new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
pdemo.setSize(500, 500);
pdemo.setVisible(true);
}
}
class Plot extends Canvas {
public int rings = 3;
}
class Plot1 extends Plot {
// Default print() calls paint():
public void paint(Graphics g) {
int w = getSize().width;
int h = getSize().height;
int xc = w / 2;
int yc = w / 2;
int x = 0, y = 0;
for(int i = 0; i < rings; i++) {
if(x < xc && y < yc) {
g.drawOval(x, y, w, h);
x += 10; y += 10;
w -= 20; h -= 20;
}
}
}
}
class Plot2 extends Plot {
// To fit the picture to the page, you must
// know whether you're printing or painting:
public void paint(Graphics g) {
int w, h;
if(g instanceof PrintGraphics) {
PrintJob pj =
((PrintGraphics)g).getPrintJob();
w = pj.getPageDimension().width;
h = pj.getPageDimension().height;
}
else {
w = getSize().width;
h = getSize().height;
}
int xc = w / 2;
int yc = w / 2;
int x = 0, y = 0;
for(int i = 0; i < rings; i++) {
if(x < xc && y < yc) {
g.drawOval(x, y, w, h);
x += 10; y += 10;
w -= 20; h -= 20;
}
}
}
}
class Plot3 extends Plot {
// Somewhat better. Separate
// printing from painting:
public void print(Graphics g) {
// Assume it's a PrintGraphics object:
PrintJob pj =
((PrintGraphics)g).getPrintJob();
int w = pj.getPageDimension().width;
int h = pj.getPageDimension().height;
doGraphics(g, w, h);
}
public void paint(Graphics g) {
int w = getSize().width;
int h = getSize().height;
doGraphics(g, w, h);
}
private void doGraphics(
Graphics g, int w, int h) {
int xc = w / 2;
int yc = w / 2;
int x = 0, y = 0;
for(int i = 0; i < rings; i++) {
if(x < xc && y < yc) {
g.drawOval(x, y, w, h);
x += 10; y += 10;
w -= 20; h -= 20;
}
}
}
}
评论0