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41 import java.awt.event.*;
42 import java.awt.*;
43 import java.applet.*;
44
45 import java.util.Vector  ;
46
47 public class DrawTest extends Applet{
48 DrawPanel panel;
49 DrawControls controls;
50
51 public void init() {
52 setLayout(new BorderLayout());
53 panel = new DrawPanel();
54 controls = new DrawControls(panel);
55 add("Center", panel);
56 add("South",controls);
57 }
58
59 public void destroy() {
60 remove(panel);
61 remove(controls);
62 }
63
64 public static void main(String args[]) {
65 Frame f = new Frame("DrawTest");
66 DrawTest drawTest = new DrawTest();
67 drawTest.init();
68 drawTest.start();
69
70 f.add("Center", drawTest);
71 f.setSize(300, 300);
72 f.show();
73 }
74 public String getAppletInfo() {
75 return "A simple drawing program.";
76 }
77 }
78
79 class DrawPanel extends Panel implements MouseListener, MouseMotionListener {
80 public static final int LINES = 0;
81 public static final int POINTS = 1;
82 int mode = LINES;
83 Vector lines = new Vector ();
84 Vector colors = new Vector ();
85 int x1,y1;
86 int x2,y2;
87
88 public DrawPanel() {
89 setBackground(Color.white);
90 addMouseMotionListener(this);
91 addMouseListener(this);
92 }
93
94 public void setDrawMode(int mode) {
95 switch (mode) {
96 case LINES:
97 case POINTS:
98 this.mode = mode;
99 break;
100 default:
101 throw new IllegalArgumentException ();
102 }
103 }
104
105
106 public void mouseDragged(MouseEvent e) {
107 e.consume();
108 switch (mode) {
109 case LINES:
110 x2 = e.getX();
111 y2 = e.getY();
112 break;
113 case POINTS:
114 default:
115 colors.addElement(getForeground());
116 lines.addElement(new Rectangle(x1, y1, e.getX(), e.getY()));
117 x1 = e.getX();
118 y1 = e.getY();
119 break;
120 }
121 repaint();
122 }
123
124 public void mouseMoved(MouseEvent e) {
125 }
126
127 public void mousePressed(MouseEvent e) {
128 e.consume();
129 switch (mode) {
130 case LINES:
131 x1 = e.getX();
132 y1 = e.getY();
133 x2 = -1;
134 break;
135 case POINTS:
136 default:
137 colors.addElement(getForeground());
138 lines.addElement(new Rectangle(e.getX(), e.getY(), -1, -1));
139 x1 = e.getX();
140 y1 = e.getY();
141 repaint();
142 break;
143 }
144 }
145
146 public void mouseReleased(MouseEvent e) {
147 e.consume();
148 switch (mode) {
149 case LINES:
150 colors.addElement(getForeground());
151 lines.addElement(new Rectangle(x1, y1, e.getX(), e.getY()));
152 x2 = -1;
153 break;
154 case POINTS:
155 default:
156 break;
157 }
158 repaint();
159 }
160
161 public void mouseEntered(MouseEvent e) {
162 }
163
164 public void mouseExited(MouseEvent e) {
165 }
166
167 public void mouseClicked(MouseEvent e) {
168 }
169
170 public void paint(Graphics g) {
171 int np = lines.size();
172
173
174 g.setColor(getForeground());
175 for (int i=0; i < np; i++) {
176 Rectangle p = (Rectangle)lines.elementAt(i);
177 g.setColor((Color)colors.elementAt(i));
178 if (p.width != -1) {
179 g.drawLine(p.x, p.y, p.width, p.height);
180 } else {
181 g.drawLine(p.x, p.y, p.x, p.y);
182 }
183 }
184 if (mode == LINES) {
185 g.setColor(getForeground());
186 if (x2 != -1) {
187 g.drawLine(x1, y1, x2, y2);
188 }
189 }
190 }
191 }
192
193
194 class DrawControls extends Panel implements ItemListener {
195 DrawPanel target;
196
197 public DrawControls(DrawPanel target) {
198 this.target = target;
199 setLayout(new FlowLayout());
200 setBackground(Color.lightGray);
201 target.setForeground(Color.red);
202 CheckboxGroup group = new CheckboxGroup();
203 Checkbox b;
204 add(b = new Checkbox(null, group, false));
205 b.addItemListener(this);
206 b.setForeground(Color.red);
207 add(b = new Checkbox(null, group, false));
208 b.addItemListener(this);
209 b.setForeground(Color.green);
210 add(b = new Checkbox(null, group, false));
211 b.addItemListener(this);
212 b.setForeground(Color.blue);
213 add(b = new Checkbox(null, group, false));
214 b.addItemListener(this);
215 b.setForeground(Color.pink);
216 add(b = new Checkbox(null, group, false));
217 b.addItemListener(this);
218 b.setForeground(Color.orange);
219 add(b = new Checkbox(null, group, true));
220 b.addItemListener(this);
221 b.setForeground(Color.black);
222 target.setForeground(b.getForeground());
223 Choice shapes = new Choice();
224 shapes.addItemListener(this);
225 shapes.addItem("Lines");
226 shapes.addItem("Points");
227 shapes.setBackground(Color.lightGray);
228 add(shapes);
229 }
230
231 public void paint(Graphics g) {
232 Rectangle r = getBounds();
233 g.setColor(Color.lightGray);
234 g.draw3DRect(0, 0, r.width, r.height, false);
235
236 int n = getComponentCount();
237 for(int i=0; i<n; i++) {
238 Component comp = getComponent(i);
239 if (comp instanceof Checkbox) {
240 Point loc = comp.getLocation();
241 Dimension d = comp.getSize();
242 g.setColor(comp.getForeground());
243 g.drawRect(loc.x-1, loc.y-1, d.width+1, d.height+1);
244 }
245 }
246 }
247
248 public void itemStateChanged(ItemEvent e) {
249 if (e.getSource() instanceof Checkbox) {
250 target.setForeground(((Component)e.getSource()).getForeground());
251 } else if (e.getSource() instanceof Choice) {
252 String choice = (String ) e.getItem();
253 if (choice.equals("Lines")) {
254 target.setDrawMode(DrawPanel.LINES);
255 } else if (choice.equals("Points")) {
256 target.setDrawMode(DrawPanel.POINTS);
257 }
258 }
259 }
260 }
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Java API By Example, From Geeks To Geeks.