Wegen geänderter Sicherheitseinstellungen kann dieses Applet aktuell nicht ausgeführt werden. Man studiere den Quellcode.
Dieses applet wird im Body des Quelltext dieses HTML-Dokuments wie folgt aufgerufen:
.....
<applet code="DrawTest.class" width="400" height=200">
</applet>
.....
Der Quelltext von "DrawTest.java" (von Sami Shaio, SUN Microsystems):
/* **************************************************************************************** */
/*
* @(#)DrawTest.java 1.14 95/09/01 Sami Shaio
*
* Copyright (c) 1994-1995 Sun Microsystems, Inc. All Rights Reserved.
*/
import java.awt.*;
import java.applet.*;
import java.util.Vector;
public class DrawTest extends applet {
public void init() {
setLayout(new BorderLayout());
DrawPanel dp = new DrawPanel();
add("Center", dp);
add("South",new DrawControls(dp));
}
public boolean handleEvent(Event e) {
switch (e.id) {
case Event.WINDOW_DESTROY:
System.exit(0);
return true;
default:
return false;
}
}
public static void main(String args[]) {
Frame f = new Frame("DrawTest");
DrawTest drawTest = new DrawTest();
drawTest.init();
drawTest.start();
f.add("Center", drawTest);
f.resize(300, 300);
f.show();
}
}
class DrawPanel extends Panel {
public static final int LINES = 0;
public static final int POINTS = 1;
int mode = LINES;
Vector lines = new Vector();
Vector colors = new Vector();
int x1,y1;
int x2,y2;
int xl, yl;
public DrawPanel() {
setBackground(Color.white);
}
public void setDrawMode(int mode) {
switch (mode) {
case LINES:
case POINTS:
this.mode = mode;
break;
default:
throw new IllegalArgumentException();
}
}
public boolean handleEvent(Event e) {
switch (e.id) {
case Event.MOUSE_DOWN:
switch (mode) {
case LINES:
x1 = e.x;
y1 = e.y;
x2 = -1;
break;
case POINTS:
default:
colors.addElement(getForeground());
lines.addElement(new Rectangle(e.x, e.y, -1, -1));
x1 = e.x;
y1 = e.y;
repaint();
break;
}
return true;
case Event.MOUSE_UP:
switch (mode) {
case LINES:
colors.addElement(getForeground());
lines.addElement(new Rectangle(x1, y1, e.x, e.y));
x2 = xl = -1;
break;
case POINTS:
default:
break;
}
repaint();
return true;
case Event.MOUSE_DRAG:
switch (mode) {
case LINES:
xl = x2;
yl = y2;
x2 = e.x;
y2 = e.y;
break;
case POINTS:
default:
colors.addElement(getForeground());
lines.addElement(new Rectangle(x1, y1, e.x, e.y));
x1 = e.x;
y1 = e.y;
break;
}
repaint();
return true;
case Event.WINDOW_DESTROY:
System.exit(0);
return true;
default:
return false;
}
}
public void paint(Graphics g) {
int np = lines.size();
/* draw the current lines */
g.setColor(getForeground());
g.setPaintMode();
for (int i=0; i < np; i++) {
Rectangle p = (Rectangle)lines.elementAt(i);
g.setColor((Color)colors.elementAt(i));
if (p.width != -1) {
g.drawLine(p.x, p.y, p.width, p.height);
} else {
g.drawLine(p.x, p.y, p.x, p.y);
}
}
if (mode == LINES) {
g.setXORMode(getBackground());
if (xl != -1) {
/* erase the last line. */
g.drawLine(x1, y1, xl, yl);
}
g.setColor(getForeground());
g.setPaintMode();
if (x2 != -1) {
g.drawLine(x1, y1, x2, y2);
}
}
}
}
class DrawControls extends Panel {
DrawPanel target;
public DrawControls(DrawPanel target) {
this.target = target;
setLayout(new FlowLayout());
setBackground(Color.lightGray);
target.setForeground(Color.red);
CheckboxGroup group = new CheckboxGroup();
Checkbox b;
add(b = new Checkbox(null, group, false));
b.setBackground(Color.red);
add(b = new Checkbox(null, group, false));
b.setBackground(Color.green);
add(b = new Checkbox(null, group, false));
b.setBackground(Color.blue);
add(b = new Checkbox(null, group, false));
b.setBackground(Color.pink);
add(b = new Checkbox(null, group, false));
b.setBackground(Color.orange);
add(b = new Checkbox(null, group, true));
b.setBackground(Color.black);
target.setForeground(b.getForeground());
Choice shapes = new Choice();
shapes.addItem("Lines");
shapes.addItem("Points");
shapes.setBackground(Color.lightGray);
add(shapes);
}
public void paint(Graphics g) {
Rectangle r = bounds();
g.setColor(Color.lightGray);
g.draw3DRect(0, 0, r.width, r.height, false);
}
public boolean action(Event e, Object arg) {
if (e.target instanceof Checkbox) {
target.setForeground(((Component)e.target).getBackground());
} else if (e.target instanceof Choice) {
String choice = (String)arg;
if (choice.equals("Lines")) {
target.setDrawMode(DrawPanel.LINES);
} else if (choice.equals("Points")) {
target.setDrawMode(DrawPanel.POINTS);
}
}
return true;
}
}
/* **************************************************************************************** */