窗口应用程序。
本例在上一版的基础上实现了高亮元素、移动元素、上下文菜单、旋转元素、设置自定义颜色。
1、自定义常量包：
1 // Defines application wide constants 2 package Constants; 3 import java.awt.*; 4 import javax.swing.*; 5 import java.awt.image.BufferedImage; 6 7 public class SketcherConstants { 8 // Path for images 9 public final static String imagePath = "E:/JavaProject/BeginningJava/Images/"; 10 11 // Toolbar icons 12 public final static Icon NEW24 = new ImageIcon(imagePath + "New24.gif"); 13 public final static Icon OPEN24 = new ImageIcon(imagePath + "Open24.gif"); 14 public final static Icon SAVE24 = new ImageIcon(imagePath + "Save24.gif"); 15 public final static Icon SAVEAS24 = new ImageIcon(imagePath + "SaveAs24.gif"); 16 public final static Icon PRINT24 = new ImageIcon(imagePath + "Print24.gif"); 17 18 public final static Icon LINE24 = new ImageIcon(imagePath + "Line24.gif"); 19 public final static Icon RECTANGLE24 = new ImageIcon(imagePath + "Rectangle24.gif"); 20 public final static Icon CIRCLE24 = new ImageIcon(imagePath + "Circle24.gif"); 21 public final static Icon CURVE24 = new ImageIcon(imagePath + "Curve24.gif"); 22 public final static Icon TEXT24 = new ImageIcon(imagePath + "Text24.gif"); 23 24 public final static Icon RED24 = new ImageIcon(imagePath + "Red24.gif"); 25 public final static Icon GREEN24 = new ImageIcon(imagePath + "Green24.gif"); 26 public final static Icon BLUE24 = new ImageIcon(imagePath + "Blue24.gif"); 27 public final static Icon YELLOW24 = new ImageIcon(imagePath + "Yellow24.gif"); 28 public final static ImageIcon CUSTOM24 = new ImageIcon(new BufferedImage(24, 24, BufferedImage.TYPE_INT_ARGB)); 29 30 // Menu item icons 31 public final static Icon NEW16 = new ImageIcon(imagePath + "new16.gif"); 32 public final static Icon OPEN16 = new ImageIcon(imagePath + "Open16.gif"); 33 public final static Icon SAVE16 = new ImageIcon(imagePath + "Save16.gif"); 34 public final static Icon SAVEAS16 = new ImageIcon(imagePath + "SaveAs16.gif"); 35 public final static Icon PRINT16 = new ImageIcon(imagePath + "print16.gif"); 36 37 public final static Icon LINE16 = new ImageIcon(imagePath + "Line16.gif"); 38 public final static Icon RECTANGLE16 = new ImageIcon(imagePath + "Rectangle16.gif"); 39 public final static Icon CIRCLE16 = new ImageIcon(imagePath + "Circle16.gif"); 40 public final static Icon CURVE16 = new ImageIcon(imagePath + "Curve16.gif"); 41 public final static Icon TEXT16 = new ImageIcon(imagePath + "Text16.gif"); 42 43 public final static Icon RED16 = new ImageIcon(imagePath + "Red16.gif"); 44 public final static Icon GREEN16 = new ImageIcon(imagePath + "Green16.gif"); 45 public final static Icon BLUE16 = new ImageIcon(imagePath + "Blue16.gif"); 46 public final static Icon YELLOW16 = new ImageIcon(imagePath + "Yellow16.gif"); 47 public final static ImageIcon CUSTOM16 = new ImageIcon(new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB)); 48 49 // Element type definitions 50 public final static int LINE = 101; 51 public final static int RECTANGLE = 102; 52 public final static int CIRCLE = 103; 53 public final static int CURVE = 104; 54 public final static int TEXT = 105; 55 56 // Initial conditions 57 public final static int DEFAULT_ELEMENT_TYPE = LINE; 58 public final static Color DEFAULT_ELEMENT_COLOR = Color.BLUE; 59 public final static Color HIGHLIGHT_COLOR = Color.MAGENTA; 60 public final static Font DEFAULT_FONT = new Font("Serif", Font.BOLD, 12); 61 62 // Font point size range specification 63 public final static int POINT_SIZE_MIN = 8; // Minimum font point size 64 public final static int POINT_SIZE_MAX = 24; // Maximum font point size 65 public final static int POINT_SIZE_STEP = 2; // Point size step 66 67 // Operating modes 68 public final static String NORMAL = "Normal"; 69 public final static String MOVE = "Move"; 70 public final static String ROTATE = "Rotate"; 71 }
2、窗口框架：
1 // Frame for the Sketcher application 2 import javax.swing.*; 3 import javax.swing.border.*; 4 import java.awt.event.*; 5 import java.awt.*; 6 import java.awt.image.BufferedImage; 7 import java.awt.font.TextLayout; 8 import java.awt.geom.Rectangle2D; 9 10 import static java.awt.event.InputEvent.*; 11 import static java.awt.Color.*; 12 import static Constants.SketcherConstants.*; 13 import static javax.swing.Action.*; 14 15 @SuppressWarnings("serial") 16 public class SketcherFrame extends JFrame implements ActionListener { 17 // Constructor 18 public SketcherFrame(String title, Sketcher theApp) { 19 setTitle(title); // Set the window title 20 this.theApp = theApp; // Save app. object reference 21 setJMenuBar(menuBar); // Add the menu bar to the window 22 setDefaultCloseOperation(EXIT_ON_CLOSE); // Default is exit the application 23 24 setCustomIconColor(CUSTOM16,customColor); // Setup small custom color icon 25 setCustomIconColor(CUSTOM24,customColor); // Setup large custom color icon 26 createFileMenu(); // Create the File menu 27 createElementMenu(); // Create the element menu 28 createColorMenu(); // Create the element menu 29 optionsMenu = new JMenu("Options"); // Create options menu 30 optionsMenu.setMnemonic('O'); // Create shortcut 31 menuBar.add(optionsMenu); // Add options to menu bar 32 33 createPopupMenu(); // Create popup 34 35 // Add the font choice item to the options menu 36 fontItem = new JMenuItem("Choose font..."); 37 fontItem.addActionListener(this); 38 optionsMenu.add(fontItem); 39 40 fontDlg = new FontDialog(this); // Create the font dialog 41 42 createToolbar(); 43 toolBar.setRollover(true); 44 45 JMenu helpMenu = new JMenu("Help"); // Create Help menu 46 helpMenu.setMnemonic('H'); // Create Help shortcut 47 48 // Add the About item to the Help menu 49 aboutItem = new JMenuItem("About"); // Create About menu item 50 aboutItem.addActionListener(this); // Listener is the frame 51 helpMenu.add(aboutItem); // Add item to menu 52 menuBar.add(helpMenu); // Add Help menu to menu bar 53 54 getContentPane().add(toolBar, BorderLayout.NORTH); // Add the toolbar 55 getContentPane().add(statusBar, BorderLayout.SOUTH); // Add the statusbar 56 } 57 58 // Create File menu item actions 59 private void createFileMenuActions() { 60 newAction = new FileAction("New", 'N', CTRL_DOWN_MASK); 61 openAction = new FileAction("Open", 'O', CTRL_DOWN_MASK); 62 closeAction = new FileAction("Close"); 63 saveAction = new FileAction("Save", 'S', CTRL_DOWN_MASK); 64 saveAsAction = new FileAction("Save As..."); 65 printAction = new FileAction("Print", 'P', CTRL_DOWN_MASK); 66 exitAction = new FileAction("Exit", 'X', CTRL_DOWN_MASK); 67 68 // Initialize the array 69 FileAction[] actions = {openAction, closeAction, saveAction, saveAsAction, printAction, exitAction}; 70 fileActions = actions; 71 72 // Add toolbar icons 73 newAction.putValue(LARGE_ICON_KEY, NEW24); 74 openAction.putValue(LARGE_ICON_KEY, OPEN24); 75 saveAction.putValue(LARGE_ICON_KEY, SAVE24); 76 saveAsAction.putValue(LARGE_ICON_KEY, SAVEAS24); 77 printAction.putValue(LARGE_ICON_KEY, PRINT24); 78 79 // Add menu item icons 80 newAction.putValue(SMALL_ICON, NEW16); 81 openAction.putValue(SMALL_ICON, OPEN16); 82 saveAction.putValue(SMALL_ICON, SAVE16); 83 saveAsAction.putValue(SMALL_ICON,SAVEAS16); 84 printAction.putValue(SMALL_ICON, PRINT16); 85 86 // Add tooltip text 87 newAction.putValue(SHORT_DESCRIPTION, "Create a new sketch"); 88 openAction.putValue(SHORT_DESCRIPTION, "Read a sketch from a file"); 89 closeAction.putValue(SHORT_DESCRIPTION, "Close the current sketch"); 90 saveAction.putValue(SHORT_DESCRIPTION, "Save the current sketch to file"); 91 saveAsAction.putValue(SHORT_DESCRIPTION, "Save the current sketch to a new file"); 92 printAction.putValue(SHORT_DESCRIPTION, "Print the current sketch"); 93 exitAction.putValue(SHORT_DESCRIPTION, "Exit Sketcher"); 94 } 95 96 // Helper method to set custom icon color 97 private void setCustomIconColor(ImageIcon icon, Color color) { 98 BufferedImage image = (BufferedImage)(icon.getImage()); 99 int width = image.getWidth(); // Image width 100 int indent = width == 16 ? 3 : 2; // Indent for filled rectangle 101 int rectSize = width - 2*indent; // Filled rectangle size 102 Graphics2D g2D = image.createGraphics(); 103 g2D.setPaint(color); 104 g2D.fillRect(indent,indent,rectSize,rectSize); // Fill centered rectangle 105 if(width == 24) { 106 TextLayout textLayout = new TextLayout("C", g2D.getFont(), g2D.getFontRenderContext()); 107 Rectangle2D.Float rect = (Rectangle2D.Float)textLayout.getBounds(); 108 g2D.setPaint(new Color(255-color.getRed(),255-color.getGreen(), 255-color.getBlue())); 109 g2D.drawString("C", (width-rect.width)/2, (width+rect.height)/2); 110 } 111 g2D.dispose(); 112 } 113 114 115 // Create the File menu 116 private void createFileMenu() { 117 JMenu fileMenu = new JMenu("File"); // Create File menu 118 fileMenu.setMnemonic('F'); // Create shortcut 119 createFileMenuActions(); // Create Actions for File menu item 120 121 // Construct the file drop-down menu 122 fileMenu.add(newAction); // New Sketch menu item 123 fileMenu.add(openAction); // Open sketch menu item 124 fileMenu.add(closeAction); // Close sketch menu item 125 fileMenu.addSeparator(); // Add separator 126 fileMenu.add(saveAction); // Save sketch to file 127 fileMenu.add(saveAsAction); // Save As menu item 128 fileMenu.addSeparator(); // Add separator 129 fileMenu.add(printAction); // Print sketch menu item 130 fileMenu.addSeparator(); // Add separator 131 fileMenu.add(exitAction); // Print sketch menu item 132 menuBar.add(fileMenu); // Add the file menu 133 } 134 135 // Create Element menu actions 136 private void createElementTypeActions() { 137 lineAction = new TypeAction("Line", LINE, 'L', CTRL_DOWN_MASK); 138 rectangleAction = new TypeAction("Rectangle", RECTANGLE, 'R', CTRL_DOWN_MASK); 139 circleAction = new TypeAction("Circle", CIRCLE,'C', CTRL_DOWN_MASK); 140 curveAction = new TypeAction("Curve", CURVE,'U', CTRL_DOWN_MASK); 141 textAction = new TypeAction("Text", TEXT,'T', CTRL_DOWN_MASK); 142 143 // Initialize the array 144 TypeAction[] actions = {lineAction, rectangleAction, circleAction, curveAction, textAction}; 145 typeActions = actions; 146 147 // Add toolbar icons 148 lineAction.putValue(LARGE_ICON_KEY, LINE24); 149 rectangleAction.putValue(LARGE_ICON_KEY, RECTANGLE24); 150 circleAction.putValue(LARGE_ICON_KEY, CIRCLE24); 151 curveAction.putValue(LARGE_ICON_KEY, CURVE24); 152 textAction.putValue(LARGE_ICON_KEY, TEXT24); 153 154 // Add menu item icons 155 lineAction.putValue(SMALL_ICON, LINE16); 156 rectangleAction.putValue(SMALL_ICON, RECTANGLE16); 157 circleAction.putValue(SMALL_ICON, CIRCLE16); 158 curveAction.putValue(SMALL_ICON, CURVE16); 159 textAction.putValue(SMALL_ICON, TEXT16); 160 161 // Add tooltip text 162 lineAction.putValue(SHORT_DESCRIPTION, "Draw lines"); 163 rectangleAction.putValue(SHORT_DESCRIPTION, "Draw rectangles"); 164 circleAction.putValue(SHORT_DESCRIPTION, "Draw circles"); 165 curveAction.putValue(SHORT_DESCRIPTION, "Draw curves"); 166 textAction.putValue(SHORT_DESCRIPTION, "Draw text"); 167 } 168 169 // Create the Elements menu 170 private void createElementMenu() { 171 createElementTypeActions(); 172 elementMenu = new JMenu("Elements"); // Create Elements menu 173 elementMenu.setMnemonic('E'); // Create shortcut 174 createRadioButtonDropDown(elementMenu, typeActions, lineAction); 175 menuBar.add(elementMenu); // Add the element menu 176 } 177 178 // Create Color menu actions 179 private void createElementColorActions() { 180 redAction = new ColorAction("Red", RED, 'R', CTRL_DOWN_MASK|ALT_DOWN_MASK); 181 yellowAction = new ColorAction("Yellow", YELLOW, 'Y', CTRL_DOWN_MASK|ALT_DOWN_MASK); 182 greenAction = new ColorAction("Green", GREEN, 'G', CTRL_DOWN_MASK|ALT_DOWN_MASK); 183 blueAction = new ColorAction("Blue", BLUE, 'B', CTRL_DOWN_MASK|ALT_DOWN_MASK); 184 customAction = new ColorAction("Custom...", BLUE, 'C', CTRL_DOWN_MASK|ALT_DOWN_MASK); 185 186 // Initialize the array 187 ColorAction[] actions = {redAction, greenAction, blueAction, yellowAction, customAction}; 188 colorActions = actions; 189 190 // Add toolbar icons 191 redAction.putValue(LARGE_ICON_KEY, RED24); 192 greenAction.putValue(LARGE_ICON_KEY, GREEN24); 193 blueAction.putValue(LARGE_ICON_KEY, BLUE24); 194 yellowAction.putValue(LARGE_ICON_KEY, YELLOW24); 195 customAction.putValue(LARGE_ICON_KEY, CUSTOM24); 196 197 // Add menu item icons 198 redAction.putValue(SMALL_ICON, RED16); 199 greenAction.putValue(SMALL_ICON, GREEN16); 200 blueAction.putValue(SMALL_ICON, BLUE16); 201 yellowAction.putValue(SMALL_ICON, YELLOW16); 202 customAction.putValue(SMALL_ICON, CUSTOM16); 203 204 // Add tooltip text 205 redAction.putValue(SHORT_DESCRIPTION, "Draw in red"); 206 greenAction.putValue(SHORT_DESCRIPTION, "Draw in green"); 207 blueAction.putValue(SHORT_DESCRIPTION, "Draw in blue"); 208 yellowAction.putValue(SHORT_DESCRIPTION, "Draw in yellow"); 209 customAction.putValue(SHORT_DESCRIPTION, "Draw in custom color"); 210 } 211 212 // Create the Color menu 213 private void createColorMenu() { 214 createElementColorActions(); 215 colorMenu = new JMenu("Color"); // Create Elements menu 216 colorMenu.setMnemonic('C'); // Create shortcut 217 createRadioButtonDropDown(colorMenu, colorActions, blueAction); 218 menuBar.add(colorMenu); // Add the color menu 219 } 220 221 // Menu creation helper 222 private void createRadioButtonDropDown(JMenu menu, Action[] actions, Action selected) { 223 ButtonGroup group = new ButtonGroup(); 224 JRadioButtonMenuItem item = null; 225 for(Action action : actions) { 226 group.add(menu.add(item = new JRadioButtonMenuItem(action))); 227 if(action == selected) { 228 item.setSelected(true); // This is default selected 229 } 230 } 231 } 232 233 // Create pop-up menu 234 private void createPopupMenu() { 235 // Element menu items 236 popup.add(new JMenuItem(lineAction)); 237 popup.add(new JMenuItem(rectangleAction)); 238 popup.add(new JMenuItem(circleAction)); 239 popup.add(new JMenuItem(curveAction)); 240 popup.add(new JMenuItem(textAction)); 241 242 popup.addSeparator(); 243 244 // Color menu items 245 popup.add(new JMenuItem(redAction)); 246 popup.add(new JMenuItem(yellowAction)); 247 popup.add(new JMenuItem(greenAction)); 248 popup.add(new JMenuItem(blueAction)); 249 popup.add(new JMenuItem(customAction)); 250 } 251 252 // Create toolbar buttons on the toolbar 253 private void createToolbar() { 254 for(FileAction action: fileActions){ 255 if(action != exitAction && action != closeAction) 256 addToolbarButton(action); // Add the toolbar button 257 } 258 toolBar.addSeparator(); 259 260 // Create Color menu buttons 261 for(ColorAction action:colorActions){ 262 addToolbarButton(action); // Add the toolbar button 263 } 264 265 toolBar.addSeparator(); 266 267 // Create Elements menu buttons 268 for(TypeAction action:typeActions){ 269 addToolbarButton(action); // Add the toolbar button 270 } 271 } 272 273 // Create and add a toolbar button 274 private void addToolbarButton(Action action) { 275 JButton button = new JButton(action); // Create from Action 276 button.setBorder(BorderFactory.createCompoundBorder( // Add button border 277 new EmptyBorder(2,5,5,2), // Outside border 278 BorderFactory.createRaisedBevelBorder())); // Inside border 279 button.setHideActionText(true); // No label on the button 280 toolBar.add(button); // Add the toolbar button 281 } 282 283 // Return the current drawing color 284 public Color getElementColor() { 285 return elementColor; 286 } 287 288 // Return the current element type 289 public int getElementType() { 290 return elementType; 291 } 292 293 // Return current text font 294 public Font getFont() { 295 return textFont; 296 } 297 298 // Method to set the current font 299 public void setFont(Font font) { 300 textFont = font; 301 } 302 303 // Retrieve the pop-up menu 304 public JPopupMenu getPopup() { 305 return popup; 306 } 307 308 // Set radio button menu checks 309 private void setChecks(JMenu menu, Object eventSource) { 310 if(eventSource instanceof JButton){ 311 JButton button = (JButton)eventSource; 312 Action action = button.getAction(); 313 for(int i = 0 ; i<menu.getItemCount() ; ++i) { 314 JMenuItem item = menu.getItem(i); 315 item.setSelected(item.getAction() == action); 316 } 317 } 318 } 319 320 // Handle About menu events 321 public void actionPerformed(ActionEvent e) { 322 if(e.getSource() == aboutItem) { 323 // Create about dialog with the app window as parent 324 JOptionPane.showMessageDialog(this, // Parent 325 "Sketcher Copyright Ivor Horton 2011", // Message 326 "About Sketcher", // Title 327 JOptionPane.INFORMATION_MESSAGE); // Message type 328 } else if(e.getSource() == fontItem) { // Set the dialog window position 329 fontDlg.setLocationRelativeTo(this); 330 fontDlg.setVisible(true); // Show the dialog 331 } 332 } 333 334 // Inner class defining Action objects for File menu items 335 class FileAction extends AbstractAction { 336 // Create action with a name 337 FileAction(String name) { 338 super(name); 339 } 340 341 // Create action with a name and accelerator 342 FileAction(String name, char ch, int modifiers) { 343 super(name); 344 putValue(ACCELERATOR_KEY, KeyStroke.getKeyStroke(ch, modifiers)); 345 346 // Now find the character to underline 347 int index = name.toUpperCase().indexOf(ch); 348 if(index != -1) { 349 putValue(DISPLAYED_MNEMONIC_INDEX_KEY, index); 350 } 351 } 352 353 // Event handler 354 public void actionPerformed(ActionEvent e) { 355 // You will add action code here eventually... 356 } 357 } 358 359 // Inner class defining Action objects for Element type menu items 360 class TypeAction extends AbstractAction { 361 // Create action with just a name property 362 TypeAction(String name, int typeID) { 363 super(name); 364 this.typeID = typeID; 365 } 366 367 // Create action with a name and an accelerator 368 private TypeAction(String name,int typeID, char ch, int modifiers) { 369 this(name, typeID); 370 putValue(ACCELERATOR_KEY, KeyStroke.getKeyStroke(ch, modifiers)); 371 372 // Now find the character to underline 373 int index = name.toUpperCase().indexOf(ch); 374 if(index != -1) { 375 putValue(DISPLAYED_MNEMONIC_INDEX_KEY, index); 376 } 377 } 378 379 public void actionPerformed(ActionEvent e) { 380 elementType = typeID; 381 setChecks(elementMenu, e.getSource()); 382 statusBar.setTypePane(typeID); 383 } 384 385 private int typeID; 386 } 387 388 // Handles color menu items 389 class ColorAction extends AbstractAction { 390 // Create an action with a name and a color 391 public ColorAction(String name, Color color) { 392 super(name); 393 this.color = color; 394 } 395 396 // Create an action with a name, a color, and an accelerator 397 public ColorAction(String name, Color color, char ch, int modifiers) { 398 this(name, color); 399 putValue(ACCELERATOR_KEY, KeyStroke.getKeyStroke(ch, modifiers)); 400 401 // Now find the character to underline 402 int index = name.toUpperCase().indexOf(ch); 403 if(index != -1) { 404 putValue(DISPLAYED_MNEMONIC_INDEX_KEY, index); 405 } 406 } 407 408 public void actionPerformed(ActionEvent e) { 409 if(this == customAction) { 410 // This could be a new custom color 411 Color newColor = JColorChooser.showDialog(SketcherFrame.this, "Select Custom Color", customColor); 412 if(newColor != null) { 413 elementColor = customColor = newColor; 414 415 // Setup small custom color icons 416 setCustomIconColor(CUSTOM16,customColor); 417 setCustomIconColor(CUSTOM24,customColor); 418 toolBar.repaint(); // Repaint the toolbar 419 } 420 } else { 421 // This is just a standard color change 422 elementColor = color; 423 } 424 statusBar.setColorPane(elementColor); // Update the status bar 425 setChecks(colorMenu, e.getSource()); // Set Color menu checks 426 } 427 428 private Color color; 429 } 430 431 // File actions 432 private FileAction newAction, openAction, closeAction, saveAction, saveAsAction, printAction, exitAction; 433 private FileAction[] fileActions; // File actions as an array 434 435 // Element type actions 436 private TypeAction lineAction, rectangleAction, circleAction, curveAction, textAction; 437 private TypeAction[] typeActions; // Type actions as an array 438 439 // Element color actions 440 private ColorAction redAction, yellowAction,greenAction, blueAction, customAction; 441 private ColorAction[] colorActions; // Color actions as an array 442 443 private JMenuBar menuBar = new JMenuBar(); // Window menu bar 444 private JMenu elementMenu; // Elements menu 445 private JMenu colorMenu; // Color menu 446 private JMenu optionsMenu; // Options menu 447 448 private StatusBar statusBar = new StatusBar(); // Window status bar 449 private FontDialog fontDlg; // The font dialog 450 451 private JMenuItem aboutItem; // About menu item 452 private JMenuItem fontItem; // Font chooser menu item 453 454 private JPopupMenu popup = new JPopupMenu("General"); // Window pop-up 455 private Color elementColor = DEFAULT_ELEMENT_COLOR; // Current element color 456 private Color customColor = DEFAULT_ELEMENT_COLOR; // Current custom color 457 private int elementType = DEFAULT_ELEMENT_TYPE; // Current element type 458 private Font textFont = DEFAULT_FONT; // Default font for text elements 459 private JToolBar toolBar = new JToolBar(); // Window toolbar 460 private Sketcher theApp; // The application object 461 }
3、元素类：
1 import java.awt.*; 2 import java.io.Serializable; 3 import static Constants.SketcherConstants.*; 4 import java.awt.geom.*; 5 6 public abstract class Element implements Serializable{ 7 8 public Element(Point position, Color color) { 9 this.position = new Point(position); 10 this.color = color; 11 } 12 13 protected Element(Color color) { 14 this.color = color; 15 } 16 17 // Returns the color of the element 18 public Color getColor() { 19 return color; 20 } 21 22 // Returns the position of the element 23 public Point getPosition() { 24 return position; 25 } 26 27 // Returns the bounding rectangle enclosing an element boundary 28 public java.awt.Rectangle getBounds() { 29 AffineTransform at = AffineTransform.getTranslateInstance(position.x, position.y); 30 at.rotate(angle); 31 at.translate(-position.x, -position.y); 32 return at.createTransformedShape(bounds).getBounds(); 33 } 34 35 // Set or reset highlight color 36 public void setHighlighted(boolean highlighted) { 37 this.highlighted = highlighted; 38 } 39 40 // Create a new element 41 public static Element createElement(int type, Color color, Point start, Point end) { 42 switch(type) { 43 case LINE: 44 return new Element.Line(start, end, color); 45 case RECTANGLE: 46 return new Rectangle(start, end, color); 47 case CIRCLE: 48 return new Circle(start, end, color); 49 case CURVE: 50 return new Curve(start, end, color); 51 default: 52 assert false; // We should never get to here 53 } 54 return null; 55 } 56 57 // Draw a geometric element of type Shape 58 protected void draw(Graphics2D g2D, Shape element) { 59 g2D.setPaint(highlighted ? Color.MAGENTA : color); // Set the element color 60 AffineTransform old = g2D.getTransform(); // Save copy of current transform 61 g2D.translate((double)position.x, (double)position.y); // Add a translation to current transform 62 g2D.rotate(angle); // Rotate about position 63 g2D.draw(element); // Draw the element 64 g2D.setTransform(old); // Restore original transform 65 } 66 67 // Move an element 68 public void move(int deltaX, int deltaY) { 69 position.translate(deltaX, deltaY); 70 bounds.translate(deltaX, deltaY); 71 } 72 73 // Rotate an element 74 public void setRotation(double angle) { 75 this.angle = angle; 76 } 77 78 // Get the rotation angle 79 public double getRotation() { 80 return angle; 81 } 82 83 // Nested class defining a line 84 public static class Line extends Element { 85 public Line(Point start, Point end, Color color) { 86 super(start, color); 87 line = new Line2D.Double(origin.x, origin.y, end.x - position.x, end.y - position.y); 88 bounds = new java.awt.Rectangle( 89 Math.min(start.x ,end.x), Math.min(start.y, end.y), 90 Math.abs(start.x - end.x)+1, Math.abs(start.y - end.y)+1); 91 } 92 93 // Change the end point for the line 94 public void modify(Point start, Point last) { 95 line.x2 = last.x - position.x; 96 line.y2 = last.y - position.y; 97 bounds = new java.awt.Rectangle( 98 Math.min(start.x ,last.x), Math.min(start.y, last.y), 99 Math.abs(start.x - last.x)+1, Math.abs(start.y - last.y)+1); 100 } 101 102 // Display the line 103 public void draw(Graphics2D g2D) { 104 draw(g2D, line); // Draw the line 105 } 106 private Line2D.Double line; 107 private final static long serialVersionUID = 1001L; 108 } 109 110 // Nested class defining a rectangle 111 public static class Rectangle extends Element { 112 public Rectangle(Point start, Point end, Color color) { 113 super(new Point(Math.min(start.x, end.x), Math.min(start.y, end.y)), color); 114 rectangle = new Rectangle2D.Double( 115 origin.x, origin.y, // Top-left corner 116 Math.abs(start.x - end.x), Math.abs(start.y - end.y)); // Width & height 117 bounds = new java.awt.Rectangle( 118 Math.min(start.x ,end.x), Math.min(start.y, end.y), 119 Math.abs(start.x - end.x)+1, Math.abs(start.y - end.y)+1); 120 } 121 122 // Display the rectangle 123 public void draw(Graphics2D g2D) { 124 draw(g2D, rectangle); // Draw the rectangle 125 } 126 127 // Method to redefine the rectangle 128 public void modify(Point start, Point last) { 129 bounds.x = position.x = Math.min(start.x, last.x); 130 bounds.y = position.y = Math.min(start.y, last.y); 131 rectangle.width = Math.abs(start.x - last.x); 132 rectangle.height = Math.abs(start.y - last.y); 133 bounds.width = (int)rectangle.width + 1; 134 bounds.height = (int)rectangle.height + 1; 135 } 136 137 private Rectangle2D.Double rectangle; 138 private final static long serialVersionUID = 1001L; 139 } 140 141 // Nested class defining a circle 142 public static class Circle extends Element { 143 public Circle(Point center, Point circum, Color color) { 144 super(color); 145 146 // Radius is distance from center to circumference 147 double radius = center.distance(circum); 148 position = new Point(center.x - (int)radius, center.y - (int)radius); 149 circle = new Ellipse2D.Double(origin.x, origin.y, 2.*radius, 2.*radius); 150 bounds = new java.awt.Rectangle(position.x, position.y, 151 1 + (int)circle.width, 1 + (int)circle.height); 152 } 153 154 // Display the circle 155 public void draw(Graphics2D g2D) { 156 draw(g2D, circle); // Draw the circle 157 } 158 159 // Recreate this circle 160 public void modify(Point center, Point circum) { 161 double radius = center.distance(circum); 162 circle.width = circle.height = 2*radius; 163 position.x = center.x - (int)radius; 164 position.y = center.y - (int)radius; 165 bounds = new java.awt.Rectangle(position.x, position.y, 166 1 + (int)circle.width, 1 + (int)circle.height); 167 } 168 169 private Ellipse2D.Double circle; 170 private final static long serialVersionUID = 1001L; 171 } 172 173 // Nested class defining a curve 174 public static class Curve extends Element { 175 public Curve(Point start, Point next, Color color) { 176 super(start, color); 177 curve = new GeneralPath(); 178 curve.moveTo(origin.x, origin.y); // Set current position as origin 179 curve.lineTo(next.x - position.x, next.y - position.y); // Add segment 180 bounds = new java.awt.Rectangle( 181 Math.min(start.x, next.x), Math.min(start.y, next.y), 182 Math.abs(next.x - start.x)+1, Math.abs(next.y - start.y)+1); 183 } 184 185 // Add another segment 186 public void modify(Point start, Point next) { 187 curve.lineTo(next.x - position.x, next.y - position.y); // Add segment 188 bounds.add(new java.awt.Rectangle(next.x,next.y, 1, 1)); // Extend bounds 189 } 190 191 192 // Display the curve 193 public void draw(Graphics2D g2D) { 194 draw(g2D, curve); // Draw the curve 195 } 196 197 private GeneralPath curve; 198 private final static long serialVersionUID = 1001L; 199 } 200 201 // Nested class defining a Text element 202 public static class Text extends Element { 203 public Text(String text, Point start, Color color, FontMetrics fm) { 204 super(start, color); 205 this.text = text; 206 this.font = fm.getFont(); 207 maxAscent = fm.getMaxAscent(); 208 bounds = new java.awt.Rectangle(position.x, position.y, 209 fm.stringWidth(text) + 4, maxAscent+ fm.getMaxDescent() + 4); 210 } 211 212 public void draw(Graphics2D g2D) { 213 g2D.setPaint(highlighted ? HIGHLIGHT_COLOR : color); 214 Font oldFont = g2D.getFont(); // Save the old font 215 g2D.setFont(font); // Set the new font 216 217 AffineTransform old = g2D.getTransform(); // Save the current transform 218 g2D.translate((double)position.x, (double)position.y); // Add translation transform to current 219 g2D.rotate(angle); // Rotate about position 220 // Reference point for drawString() is the baseline of the 1st character 221 g2D.drawString(text, origin.x + 2, maxAscent + 2); 222 g2D.setTransform(old); // Restore original transform 223 g2D.setFont(oldFont); // Restore the old font 224 } 225 226 public void modify(Point start, Point last) { 227 // No code is required here, but you must supply a definition 228 } 229 230 private Font font; // The font to be used 231 private int maxAscent; // Maximum ascent 232 private String text; // Text to be displayed 233 private final static long serialVersionUID = 1001L; 234 } 235 236 // Abstract Element class methods 237 public abstract void draw(Graphics2D g2D); 238 public abstract void modify(Point start, Point last); 239 240 // Element class fields 241 protected Point position; // Position of a shape 242 protected Color color; // Color of a shape 243 protected java.awt.Rectangle bounds; // Bounding rectangle 244 protected static final Point origin = new Point(); // Origin for elements 245 protected boolean highlighted = false; // Highlight flag 246 protected double angle = 0.0; // Element rotation 247 private final static long serialVersionUID = 1001L; 248 }
4、模型类：
1 import java.io.Serializable; 2 import java.util.*; 3 4 public class SketcherModel extends Observable implements Serializable, Iterable<Element> { 5 6 //Remove an element from the sketch 7 public boolean remove(Element element) { 8 boolean removed = elements.remove(element); 9 if(removed) { 10 setChanged(); 11 notifyObservers(element.getBounds()); 12 } 13 return removed; 14 } 15 16 //Add an element to the sketch 17 public void add(Element element) { 18 elements.add(element); 19 setChanged(); 20 notifyObservers(element.getBounds()); 21 } 22 23 // Get iterator for sketch elements 24 public Iterator<Element> iterator() { 25 return elements.iterator(); 26 } 27 28 29 protected LinkedList<Element> elements = new LinkedList<>(); 30 private final static long serialVersionUID = 1001L; 31 }
5、字体对话框类：
1 // Class to define a dialog to choose a font 2 import java.awt.*; 3 import javax.swing.*; 4 import java.awt.event.*; 5 import javax.swing.event.*; 6 import static Constants.SketcherConstants.*; 7 8 @SuppressWarnings("serial") 9 class FontDialog extends JDialog 10 implements ActionListener, // For buttons etc. 11 ListSelectionListener, // For list box 12 ChangeListener { // For the spinner 13 // Constructor 14 public FontDialog(SketcherFrame window) { 15 // Call the base constructor to create a modal dialog 16 super(window, "Font Selection", true); 17 font = window.getFont(); // Get the current font 18 19 // Create the dialog button panel 20 JPanel buttonPane = new JPanel(); // Create a panel to hold buttons 21 22 // Create and add the buttons to the buttonPane 23 buttonPane.add(ok = createButton("OK")); // Add the OK button 24 buttonPane.add(cancel = createButton("Cancel")); // Add the Cancel button 25 getContentPane().add(buttonPane, BorderLayout.SOUTH); // Add pane 26 27 // Code to create the data input panel 28 JPanel dataPane = new JPanel(); // Create the data entry panel 29 dataPane.setBorder(BorderFactory.createCompoundBorder( // Pane border 30 BorderFactory.createLineBorder(Color.BLACK), 31 BorderFactory.createEmptyBorder(5, 5, 5, 5))); 32 GridBagLayout gbLayout = new GridBagLayout(); // Create the layout 33 dataPane.setLayout(gbLayout); // Set the pane layout 34 GridBagConstraints constraints = new GridBagConstraints(); 35 36 // Create the font choice and add it to the input panel 37 JLabel label = new JLabel("Choose a Font"); 38 constraints.fill = GridBagConstraints.HORIZONTAL; 39 constraints.gridwidth = GridBagConstraints.REMAINDER; 40 gbLayout.setConstraints(label, constraints); 41 dataPane.add(label); 42 43 // Code to set up font list choice component 44 GraphicsEnvironment e = GraphicsEnvironment.getLocalGraphicsEnvironment(); 45 String[] fontNames = e.getAvailableFontFamilyNames(); // Get font names 46 47 fontList = new JList<>(fontNames); // Create list of font names 48 fontList.setValueIsAdjusting(true); // single event selection 49 fontList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); 50 fontList.setSelectedValue(font.getFontName(),true); 51 fontList.addListSelectionListener(this); 52 fontList.setToolTipText("Choose a font"); 53 JScrollPane chooseFont = new JScrollPane(fontList); // Scrollable list 54 chooseFont.setMinimumSize(new Dimension(400,100)); 55 chooseFont.setWheelScrollingEnabled(true); // Enable mouse wheel scroll 56 57 // Panel to display font sample 58 JPanel display = new JPanel(true); 59 fontDisplay = new JLabel("Sample Size: x X y Y z Z"); 60 fontDisplay.setFont(font); 61 fontDisplay.setPreferredSize(new Dimension(350,100)); 62 display.add(fontDisplay); 63 64 //Create a split pane with font choice at the top and font display at the bottom 65 JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, 66 true, 67 chooseFont, 68 display); 69 gbLayout.setConstraints(splitPane, constraints); // Split pane constraints 70 dataPane.add(splitPane); // Add to the data pane 71 72 // Set up the size choice using a spinner 73 JPanel sizePane = new JPanel(true); // Pane for size choices 74 label = new JLabel("Choose point size: "); // Prompt for point size 75 sizePane.add(label); // Add the prompt 76 77 chooseSize = new JSpinner(new SpinnerNumberModel(font.getSize(), 78 POINT_SIZE_MIN, POINT_SIZE_MAX, POINT_SIZE_STEP)); 79 chooseSize.setValue(font.getSize()); // Set current font size 80 chooseSize.addChangeListener(this); 81 sizePane.add(chooseSize); 82 83 // Add spinner to pane 84 gbLayout.setConstraints(sizePane, constraints); // Set pane constraints 85 dataPane.add(sizePane); // Add the pane 86 87 // Set up style options using radio buttons 88 bold = new JRadioButton("Bold", (font.getStyle() & Font.BOLD) > 0); 89 italic = new JRadioButton("Italic", (font.getStyle() & Font.ITALIC) > 0); 90 bold.addItemListener(new StyleListener(Font.BOLD)); // Add button listeners 91 italic.addItemListener(new StyleListener(Font.ITALIC)); 92 JPanel stylePane = new JPanel(true); // Create style pane 93 stylePane.add(bold); // Add buttons 94 stylePane.add(italic); // to style pane... 95 gbLayout.setConstraints(stylePane, constraints); // Set pane constraints 96 dataPane.add(stylePane); // Add the pane 97 98 getContentPane().add(dataPane, BorderLayout.CENTER); 99 pack(); 100 setVisible(false); 101 } 102 103 // Create a dialog button 104 JButton createButton(String label) { 105 JButton button = new JButton(label); // Create the button 106 button.setPreferredSize(new Dimension(80,20)); // Set the size 107 button.addActionListener(this); // Listener is the dialog 108 return button; // Return the button 109 } 110 111 // Handler for button events 112 public void actionPerformed(ActionEvent e) { 113 if(e.getSource()== ok) { // If it's the OK button 114 ((SketcherFrame)getOwner()).setFont(font); // ...set selected font 115 } else { 116 font = ((SketcherFrame)getOwner()).getFont(); // Restore the current font 117 fontDisplay.setFont(font); 118 chooseSize.setValue(font.getSize()); // Restore the point size 119 fontList.setSelectedValue(font.getName(),true); 120 int style = font.getStyle(); 121 bold.setSelected((style & Font.BOLD) > 0); // Restore the 122 italic.setSelected((style & Font.ITALIC) > 0); // style options 123 } 124 // Now hide the dialog - for ok or cancel 125 setVisible(false); 126 } 127 128 // List selection listener method 129 public void valueChanged(ListSelectionEvent e) { 130 if(!e.getValueIsAdjusting()) { 131 font = new Font(fontList.getSelectedValue(), font.getStyle(), font.getSize()); 132 fontDisplay.setFont(font); 133 fontDisplay.repaint(); 134 } 135 } 136 137 // Handle spinner state change events 138 public void stateChanged(ChangeEvent e) { 139 int fontSize = ((Number)(((JSpinner)e.getSource()).getValue())).intValue(); 140 font = font.deriveFont((float)fontSize); 141 fontDisplay.setFont(font); 142 fontDisplay.repaint(); 143 } 144 145 // Iner class defining listeners for radio buttons 146 class StyleListener implements ItemListener { 147 public StyleListener(int style) { 148 this.style = style; 149 } 150 151 // Event handler for font style changes 152 public void itemStateChanged(ItemEvent e) { 153 int fontStyle = font.getStyle(); 154 if(e.getStateChange()==ItemEvent.SELECTED) { // If style was selected 155 fontStyle |= style; // turn it on in the font style 156 } else { 157 fontStyle &= ~style; // otherwise turn it off 158 } 159 font = font.deriveFont(fontStyle); // Get a new font 160 fontDisplay.setFont(font); // Change the label font 161 fontDisplay.repaint(); // repaint 162 } 163 private int style; // Style for this listener 164 } 165 166 private JList<String> fontList; // Font list 167 private JButton ok; // OK button 168 private JButton cancel; // Cancel button 169 private JRadioButton bold; // Bold style button 170 private JRadioButton italic; // Italic style button 171 private Font font; // Currently selected font 172 private JSpinner chooseSize; // Font size options 173 private JLabel fontDisplay; // Font sample 174 }
6、状态栏类：
1 // Class defining a status bar 2 import javax.swing.*; 3 import java.awt.*; 4 import javax.swing.border.BevelBorder; 5 import static Constants.SketcherConstants.*; 6 7 @SuppressWarnings("serial") 8 class StatusBar extends JPanel { 9 // Constructor 10 public StatusBar() { 11 setLayout(new FlowLayout(FlowLayout.LEFT, 10, 3)); 12 setBackground(Color.LIGHT_GRAY); 13 setBorder(BorderFactory.createLineBorder(Color.DARK_GRAY)); 14 setColorPane(DEFAULT_ELEMENT_COLOR); 15 setTypePane(DEFAULT_ELEMENT_TYPE); 16 add(colorPane); // Add color pane to status bar 17 add(typePane); // Add type pane to status bar 18 } 19 20 // Set color pane contents 21 public void setColorPane(Color color) { 22 String text = null; // Text for the color pane 23 Icon icon = null; // Icon to be displayed 24 if(color.equals(Color.RED)) { 25 text = "RED"; 26 icon = RED16; 27 } else if(color.equals(Color.YELLOW)) { 28 text = "YELLOW"; 29 icon = YELLOW16; 30 } else if(color.equals(Color.GREEN)) { 31 text = "GREEN"; 32 icon = GREEN16; 33 } else if(color.equals(Color.BLUE)) { 34 text = "BLUE"; 35 icon = BLUE16; 36 } else { 37 text = "CUSTOM"; 38 icon = CUSTOM16; 39 } 40 colorPane.setIcon(icon); 41 colorPane.setText(text); // Set the pane text 42 } 43 44 // Set type pane label 45 public void setTypePane(int elementType) { 46 String text = null; // Text for the type pane 47 switch(elementType) { 48 case LINE: 49 text = "LINE"; 50 break; 51 case RECTANGLE: 52 text = "RECTANGLE"; 53 break; 54 case CIRCLE: 55 text = "CIRCLE"; 56 break; 57 case CURVE: 58 text = "CURVE"; 59 break; 60 case TEXT: 61 text = "TEXT"; 62 break; 63 default: 64 assert false; 65 } 66 typePane.setText(text); // Set the pane text 67 } 68 69 // Panes in the status bar 70 private StatusPane colorPane = new StatusPane("BLUE", BLUE16);; 71 private StatusPane typePane = new StatusPane("LINE"); 72 73 // Class defining a status bar pane 74 class StatusPane extends JLabel { 75 // Constructor - text only 76 public StatusPane(String text) { 77 super(text, LEFT); 78 setupPane(); 79 } 80 81 // Constructor - text with an icon 82 public StatusPane(String text, Icon icon) { 83 super(text, icon, LEFT); 84 setupPane(); 85 } 86 87 // Helper method for use by constructors 88 private void setupPane() { 89 setBackground(Color.LIGHT_GRAY); // Set background color 90 setForeground(Color.BLACK); // Set foreground color 91 setFont(paneFont); // Set the fixed font 92 setBorder(BorderFactory.createCompoundBorder( 93 BorderFactory.createBevelBorder(BevelBorder.LOWERED), // Outside border 94 BorderFactory.createEmptyBorder(0,5,0,3))); // Inside border 95 setPreferredSize(new Dimension(80,20)); 96 } 97 98 // Font for pane text 99 private Font paneFont = new Font("Serif", Font.PLAIN, 10); 100 } 101 }
7、视图类：
1 import javax.swing.*; 2 import java.util.*; 3 import java.awt.*; 4 import java.awt.event.*; 5 import javax.swing.event.MouseInputAdapter; 6 import static Constants.SketcherConstants.*; 7 import java.awt.geom.Line2D; 8 9 @SuppressWarnings("serial") 10 public class SketcherView extends JComponent implements Observer { 11 public SketcherView(Sketcher theApp) { 12 this.theApp = theApp; 13 MouseHandler handler = new MouseHandler(); // create the mouse listener 14 addMouseListener(handler); // Listen for button events 15 addMouseMotionListener(handler); // Listen for motion events 16 17 // Add the pop-up menu items 18 JMenuItem moveItem = elementPopup.add(new JMenuItem("Move")); 19 JMenuItem deleteItem = elementPopup.add(new JMenuItem("Delete")); 20 JMenuItem rotateItem = elementPopup.add(new JMenuItem("Rotate")); 21 JMenuItem sendToBackItem = elementPopup.add(new JMenuItem("Send-to-back")); 22 23 // Create the menu item listeners 24 moveItem.addActionListener(new ActionListener(){ 25 public void actionPerformed(ActionEvent e){ 26 mode = MOVE; 27 selectedElement = highlightElement; 28 } 29 }); 30 deleteItem.addActionListener(new ActionListener(){ 31 public void actionPerformed(ActionEvent e){ 32 deleteElement(); 33 } 34 }); 35 rotateItem.addActionListener(new ActionListener(){ 36 public void actionPerformed(ActionEvent e){ 37 mode = ROTATE; 38 selectedElement = highlightElement; 39 } 40 }); 41 sendToBackItem.addActionListener(new ActionListener(){ 42 public void actionPerformed(ActionEvent e){ 43 sendToBack(); // Handle the send-to-back event 44 } 45 }); 46 } 47 48 // Send-to Back operation 49 private void sendToBack() { 50 if(highlightElement != null) { 51 SketcherModel sketch = theApp.getModel(); 52 if(sketch.remove(highlightElement)) { 53 sketch.add(highlightElement); 54 } else { 55 JOptionPane.showMessageDialog( 56 SketcherView.this,"Element not found to remove.", 57 "Remove Element from Sketch", JOptionPane.ERROR_MESSAGE); 58 } 59 } 60 } 61 62 // Delete element operation 63 private void deleteElement() { 64 if(highlightElement != null) { 65 if(!theApp.getModel().remove(highlightElement)) { 66 JOptionPane.showMessageDialog( 67 SketcherView.this,"Element not found to remove.", 68 "Remove Element from Sketch", JOptionPane.ERROR_MESSAGE); 69 } 70 highlightElement = null; 71 } 72 } 73 74 // Method called by Observable object when it changes 75 public void update(Observable o, Object rectangle) { 76 if(rectangle != null) { 77 repaint((java.awt.Rectangle)rectangle); 78 } else { 79 repaint(); 80 } 81 } 82 83 // Method to draw on the view 84 @Override 85 public void paint(Graphics g) { 86 Graphics2D g2D = (Graphics2D)g; // Get a 2D device context 87 for(Element element: theApp.getModel()) { // For each element in the model 88 element.draw(g2D); // ...draw the element 89 } 90 } 91 92 class MouseHandler extends MouseInputAdapter { 93 @Override 94 public void mousePressed(MouseEvent e) { 95 start = e.getPoint(); // Save the cursor position in start 96 buttonState = e.getButton(); // Record which button was pressed 97 98 if(showContextMenu(e)) { 99 start = null; 100 buttonState = MouseEvent.NOBUTTON; 101 return; 102 } 103 104 if(theApp.getWindow().getElementType() == TEXT && mode == NORMAL) return; 105 106 // Initialize rotation angles when mode is ROTATE 107 if(mode == ROTATE && selectedElement != null) { 108 oldAngle = selectedElement.getRotation(); 109 angle = 0.0; 110 } 111 112 if(buttonState == MouseEvent.BUTTON1 && mode == NORMAL) { 113 g2D = (Graphics2D)getGraphics(); // Get graphics context 114 g2D.setXORMode(getBackground()); // Set XOR mode 115 } 116 } 117 118 119 // Show the context menu when an element is highlighted 120 private boolean showContextMenu(MouseEvent e) { 121 if(e.isPopupTrigger()){ 122 if(last != null) { // If mouse was dragged 123 start = last; // show popup at last cursor position 124 } 125 if(highlightElement == null) { // If there is no highlighted element 126 // Show the popup menu from the app window 127 theApp.getWindow().getPopup().show(SketcherView.this, start.x, start.y); 128 } else { // Otherwise... 129 // Show the element operations context menu 130 elementPopup.show(SketcherView.this, start.x, start.y); 131 } 132 return true; 133 } 134 return false; 135 } 136 137 @Override 138 public void mouseDragged(MouseEvent e) { 139 last = e.getPoint(); // Save cursor position 140 if(theApp.getWindow().getElementType() == TEXT && mode == NORMAL) return; 141 142 // Select operation based on sketching mode 143 switch(mode){ 144 case NORMAL: 145 // Creating an element 146 if(buttonState == MouseEvent.BUTTON1) { 147 if(tempElement == null) { // Is there an element? 148 tempElement = Element.createElement( // No, so create one 149 theApp.getWindow().getElementType(), 150 theApp.getWindow().getElementColor(), 151 start, last); 152 } else { 153 tempElement.draw(g2D); // Yes draw to erase it 154 tempElement.modify(start, last); // Now modify it 155 } 156 tempElement.draw(g2D); // and draw it 157 } 158 break; 159 case MOVE: 160 // Moving an element 161 if(buttonState == MouseEvent.BUTTON1 && selectedElement != null) { 162 selectedElement.move(last.x-start.x, last.y-start.y); // Move it 163 repaint(); 164 start = last; // Make start current point 165 } 166 break; 167 case ROTATE: 168 // Rotating an element 169 if(buttonState == MouseEvent.BUTTON1 && selectedElement != null) { 170 angle += getAngle(selectedElement.getPosition(), start, last); 171 if(angle != 0.0) { // If there is rotation 172 selectedElement.setRotation(oldAngle + angle); // Rotate the element 173 repaint(); // Repaint the view 174 start = last; // last is start next time 175 } 176 } 177 break; 178 } 179 } 180 181 // Helper method for calculating the rotation angle 182 double getAngle(Point position, Point start, Point last) { 183 // Get perpendicular distance from last to line from position to start 184 double perp = Line2D.ptLineDist(position.x, position.y, 185 last.x, last.y, start.x, start.y); 186 187 // Get the distance from position to start 188 double hypotenuse = position.distance(start); 189 190 if(perp < 1.0 || hypotenuse < 1.0) return 0.0; // Ensure sensible values 191 192 // Angle is the arc sine of perp/hypotenuse. Clockwise is positive angle 193 return -Line2D.relativeCCW(position.x, position.y, start.x, start.y, 194 last.x, last.y)*Math.asin(perp/hypotenuse); 195 } 196 197 @Override 198 public void mouseReleased(MouseEvent e) { 199 if(mode == MOVE || mode == ROTATE) { 200 selectedElement = null; 201 start = last = null; 202 mode = NORMAL; 203 return; 204 } 205 206 if(showContextMenu(e)) { 207 start = last = null; 208 return; 209 } 210 211 // Check for TEXT being the element type 212 if(theApp.getWindow().getElementType() == TEXT && mode == NORMAL) { 213 if(last != null) { 214 start = last = null; 215 } 216 return; 217 } 218 219 if(e.getButton() == MouseEvent.BUTTON1) { 220 buttonState = MouseEvent.NOBUTTON; // Reset the button state 221 222 if(tempElement != null) { // If there is an element... 223 theApp.getModel().add(tempElement); // ...add it to the model... 224 tempElement = null; // ...and reset the field 225 } 226 if(g2D != null) { // If there抯 a graphics context 227 g2D.dispose(); // ...release the resource... 228 g2D = null; // ...and reset field to null 229 } 230 start = last = null; // Remove any points 231 mode = NORMAL; // Always normal after mouse released 232 } 233 } 234 235 @Override 236 public void mouseClicked(MouseEvent e) { 237 // Only if it's TEXT and button 1 was clicked 238 if(theApp.getWindow().getElementType() == TEXT && 239 buttonState == MouseEvent.BUTTON1) { 240 String text = JOptionPane.showInputDialog( 241 theApp.getWindow(),"Enter Input:", 242 "Create Text Element", JOptionPane.PLAIN_MESSAGE); 243 244 if(text != null && !text.isEmpty()) { // Only if text was entered 245 g2D = (Graphics2D)getGraphics(); 246 tempElement = new Element.Text(text, 247 start, 248 theApp.getWindow().getElementColor(), 249 g2D.getFontMetrics(theApp.getWindow().getFont())); 250 g2D.dispose(); 251 g2D = null; 252 if(tempElement != null) { 253 theApp.getModel().add(tempElement); 254 } 255 } 256 tempElement = null; // Reset for next element creation 257 start = null; // Reset for next element 258 } 259 } 260 261 // Handle mouse move events 262 @Override 263 public void mouseMoved(MouseEvent e) { 264 Point cursor = e.getPoint(); // Get current cursor position 265 266 for(Element element : theApp.getModel()) { // Go through the list... 267 if(element.getBounds().contains(cursor)) { // ....under the cursor 268 if(element==highlightElement) { // If it's already highlighted 269 return; // we are done 270 } 271 272 // Un-highlight any existing highlighted element 273 if(highlightElement!= null) { // If an element is highlighted 274 highlightElement.setHighlighted(false); // un-highlight it and 275 repaint(highlightElement.getBounds()); //... redraw it 276 } 277 278 element.setHighlighted(true); // Set highlight for new element 279 highlightElement = element; // Store new highlighted element 280 repaint(highlightElement.getBounds()); 281 return; 282 } 283 } 284 285 // Here there is no element under the cursor so... 286 if(highlightElement!=null) { // If an element is highlighted... 287 highlightElement.setHighlighted(false); // ...turn off highlighting... 288 repaint(highlightElement.getBounds()); // ... and redraw the element 289 highlightElement = null; // No element highlighted 290 } 291 } 292 293 @Override 294 public void mouseEntered(MouseEvent e) { 295 setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR)); 296 } 297 298 @Override 299 public void mouseExited(MouseEvent e) { 300 setCursor(Cursor.getDefaultCursor()); 301 } 302 303 private Point start; // Stores cursor position on press 304 private Point last; // Stores cursor position on drag 305 private Element tempElement = null; // Stores a temporary element 306 private int buttonState = MouseEvent.NOBUTTON; // Records button state 307 private Graphics2D g2D = null; // Temporary graphics context 308 } 309 310 private Sketcher theApp; // The application object 311 private Element highlightElement; // Highlighted element 312 private Element selectedElement; // Element for move or rotate operation 313 private double oldAngle = 0.0; // Initial element rotation 314 private double angle = 0.0; // Additional rotation 315 316 // Element operations context menu 317 private JPopupMenu elementPopup = new JPopupMenu("Element Operations"); 318 319 private String mode = NORMAL; // Sketching mode 320 }
8、Sketcher类：
1 // Sketching application 2 import javax.swing.*; 3 import java.awt.*; 4 import java.awt.event.*; 5 6 public class Sketcher { 7 public static void main(String[] args) { 8 theApp = new Sketcher(); // Create the application object 9 SwingUtilities.invokeLater(new Runnable() { 10 public void run() { 11 theApp.createGUI(); // Call GUI creator 12 } 13 }); 14 } 15 16 // Method to create the application GUI 17 private void createGUI() { 18 window = new SketcherFrame("Sketcher", this); // Create the app window 19 Toolkit theKit = window.getToolkit(); // Get the window toolkit 20 Dimension wndSize = theKit.getScreenSize(); // Get screen size 21 22 // Set the position to screen center & size to half screen size 23 window.setSize(wndSize.width/2, wndSize.height/2); // Set window size 24 window.setLocationRelativeTo(null); // Center window 25 26 window.addWindowListener(new WindowHandler()); // Add window listener 27 28 sketch = new SketcherModel(); // Create the model 29 view = new SketcherView(this); // Create the view 30 sketch.addObserver(view); // Register view with the model 31 window.getContentPane().add(view, BorderLayout.CENTER); 32 window.setVisible(true); 33 } 34 35 // Return a reference to the application window 36 public SketcherFrame getWindow() { 37 return window; 38 } 39 40 // Return a reference to the model 41 public SketcherModel getModel() { 42 return sketch; 43 } 44 45 // Return a reference to the view 46 public SketcherView getView() { 47 return view; 48 } 49 50 // Handler class for window events 51 class WindowHandler extends WindowAdapter { 52 // Handler for window closing event 53 @Override 54 public void windowClosing(WindowEvent e) { 55 // Code to be added here... 56 } 57 } 58 59 private SketcherModel sketch; // The data model for the sketch 60 private SketcherView view; // The view of the sketch 61 private SketcherFrame window; // The application window 62 private static Sketcher theApp; // The application object 63 }