1 /* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 27 package java.awt; 28 29 import java.awt.image.BufferedImage; 30 import java.security.AccessController; 31 import java.util.Locale; 32 33 import sun.font.FontManager; 34 import sun.font.FontManagerFactory; 35 import sun.java2d.HeadlessGraphicsEnvironment; 36 import sun.java2d.SunGraphicsEnvironment; 37 import sun.security.action.GetPropertyAction; 38 39 /** 40 * 41 * The <code>GraphicsEnvironment</code> class describes the collection 42 * of {@link GraphicsDevice} objects and {@link java.awt.Font} objects 43 * available to a Java(tm) application on a particular platform. 44 * The resources in this <code>GraphicsEnvironment</code> might be local 45 * or on a remote machine. <code>GraphicsDevice</code> objects can be 46 * screens, printers or image buffers and are the destination of 47 * {@link Graphics2D} drawing methods. Each <code>GraphicsDevice</code> 48 * has a number of {@link GraphicsConfiguration} objects associated with 49 * it. These objects specify the different configurations in which the 50 * <code>GraphicsDevice</code> can be used. 51 * @see GraphicsDevice 52 * @see GraphicsConfiguration 53 */ 54 55 public abstract class GraphicsEnvironment { 56 private static GraphicsEnvironment localEnv; 57 58 /** 59 * The headless state of the Toolkit and GraphicsEnvironment 60 */ 61 private static Boolean headless; 62 63 /** 64 * The headless state assumed by default 65 */ 66 private static Boolean defaultHeadless; 67 68 /** 69 * This is an abstract class and cannot be instantiated directly. 70 * Instances must be obtained from a suitable factory or query method. 71 */ 72 protected GraphicsEnvironment() { 73 } 74 75 /** 76 * Returns the local <code>GraphicsEnvironment</code>. 77 * @return the local <code>GraphicsEnvironment</code> 78 */ 79 public static synchronized GraphicsEnvironment getLocalGraphicsEnvironment() { 80 if (localEnv == null) { 81 localEnv = createGE(); 82 } 83 84 return localEnv; 85 } 86 87 /** 88 * Creates and returns the GraphicsEnvironment, according to the 89 * system property 'java.awt.graphicsenv'. 90 * 91 * @return the graphics environment 92 */ 93 private static GraphicsEnvironment createGE() { 94 GraphicsEnvironment ge; 95 String nm = AccessController.doPrivileged(new GetPropertyAction("java.awt.graphicsenv", null)); 96 try { 97 // long t0 = System.currentTimeMillis(); 98 Class<GraphicsEnvironment> geCls; 99 try { 100 // First we try if the bootclassloader finds the requested 101 // class. This way we can avoid to run in a privileged block. 102 geCls = (Class<GraphicsEnvironment>)Class.forName(nm); 103 } catch (ClassNotFoundException ex) { 104 // If the bootclassloader fails, we try again with the 105 // application classloader. 106 ClassLoader cl = ClassLoader.getSystemClassLoader(); 107 geCls = (Class<GraphicsEnvironment>)Class.forName(nm, true, cl); 108 } 109 ge = geCls.newInstance(); 110 // long t1 = System.currentTimeMillis(); 111 // System.out.println("GE creation took " + (t1-t0)+ "ms."); 112 if (isHeadless()) { 113 ge = new HeadlessGraphicsEnvironment(ge); 114 } 115 } catch (ClassNotFoundException e) { 116 throw new Error("Could not find class: "+nm); 117 } catch (InstantiationException e) { 118 throw new Error("Could not instantiate Graphics Environment: " 119 + nm); 120 } catch (IllegalAccessException e) { 121 throw new Error ("Could not access Graphics Environment: " 122 + nm); 123 } 124 return ge; 125 } 126 127 /** 128 * Tests whether or not a display, keyboard, and mouse can be 129 * supported in this environment. If this method returns true, 130 * a HeadlessException is thrown from areas of the Toolkit 131 * and GraphicsEnvironment that are dependent on a display, 132 * keyboard, or mouse. 133 * @return <code>true</code> if this environment cannot support 134 * a display, keyboard, and mouse; <code>false</code> 135 * otherwise 136 * @see java.awt.HeadlessException 137 * @since 1.4 138 */ 139 public static boolean isHeadless() { 140 return getHeadlessProperty(); 141 } 142 143 /** 144 * @return warning message if headless state is assumed by default; 145 * null otherwise 146 * @since 1.5 147 */ 148 static String getHeadlessMessage() { 149 if (headless == null) { 150 getHeadlessProperty(); // initialize the values 151 } 152 return defaultHeadless != Boolean.TRUE ? null : 153 "\nNo X11 DISPLAY variable was set, " + 154 "but this program performed an operation which requires it."; 155 } 156 157 /** 158 * @return the value of the property "java.awt.headless" 159 * @since 1.4 160 */ 161 private static boolean getHeadlessProperty() { 162 if (headless == null) { 163 java.security.AccessController.doPrivileged( 164 new java.security.PrivilegedAction<Object>() { 165 public Object run() { 166 String nm = System.getProperty("java.awt.headless"); 167 168 if (nm == null) { 169 /* No need to ask for DISPLAY when run in a browser */ 170 if (System.getProperty("javaplugin.version") != null) { 171 headless = defaultHeadless = Boolean.FALSE; 172 } else { 173 String osName = System.getProperty("os.name"); 174 if (osName.contains("OS X") && "sun.awt.HToolkit".equals( 175 System.getProperty("awt.toolkit"))) 176 { 177 headless = defaultHeadless = Boolean.TRUE; 178 } else { 179 headless = defaultHeadless = 180 Boolean.valueOf(("Linux".equals(osName) || 181 "SunOS".equals(osName) || 182 "FreeBSD".equals(osName) || 183 "NetBSD".equals(osName) || 184 "OpenBSD".equals(osName)) && 185 (System.getenv("DISPLAY") == null)); 186 } 187 } 188 } else if (nm.equals("true")) { 189 headless = Boolean.TRUE; 190 } else { 191 headless = Boolean.FALSE; 192 } 193 return null; 194 } 195 } 196 ); 197 } 198 return headless.booleanValue(); 199 } 200 201 /** 202 * Check for headless state and throw HeadlessException if headless 203 * @since 1.4 204 */ 205 static void checkHeadless() throws HeadlessException { 206 if (isHeadless()) { 207 throw new HeadlessException(); 208 } 209 } 210 211 /** 212 * Returns whether or not a display, keyboard, and mouse can be 213 * supported in this graphics environment. If this returns true, 214 * <code>HeadlessException</code> will be thrown from areas of the 215 * graphics environment that are dependent on a display, keyboard, or 216 * mouse. 217 * @return <code>true</code> if a display, keyboard, and mouse 218 * can be supported in this environment; <code>false</code> 219 * otherwise 220 * @see java.awt.HeadlessException 221 * @see #isHeadless 222 * @since 1.4 223 */ 224 public boolean isHeadlessInstance() { 225 // By default (local graphics environment), simply check the 226 // headless property. 227 return getHeadlessProperty(); 228 } 229 230 /** 231 * Returns an array of all of the screen <code>GraphicsDevice</code> 232 * objects. 233 * @return an array containing all the <code>GraphicsDevice</code> 234 * objects that represent screen devices 235 * @exception HeadlessException if isHeadless() returns true 236 * @see #isHeadless() 237 */ 238 public abstract GraphicsDevice[] getScreenDevices() 239 throws HeadlessException; 240 241 /** 242 * Returns the default screen <code>GraphicsDevice</code>. 243 * @return the <code>GraphicsDevice</code> that represents the 244 * default screen device 245 * @exception HeadlessException if isHeadless() returns true 246 * @see #isHeadless() 247 */ 248 public abstract GraphicsDevice getDefaultScreenDevice() 249 throws HeadlessException; 250 251 /** 252 * Returns a <code>Graphics2D</code> object for rendering into the 253 * specified {@link BufferedImage}. 254 * @param img the specified <code>BufferedImage</code> 255 * @return a <code>Graphics2D</code> to be used for rendering into 256 * the specified <code>BufferedImage</code> 257 * @throws NullPointerException if <code>img</code> is null 258 */ 259 public abstract Graphics2D createGraphics(BufferedImage img); 260 261 /** 262 * Returns an array containing a one-point size instance of all fonts 263 * available in this <code>GraphicsEnvironment</code>. Typical usage 264 * would be to allow a user to select a particular font. Then, the 265 * application can size the font and set various font attributes by 266 * calling the <code>deriveFont</code> method on the chosen instance. 267 * <p> 268 * This method provides for the application the most precise control 269 * over which <code>Font</code> instance is used to render text. 270 * If a font in this <code>GraphicsEnvironment</code> has multiple 271 * programmable variations, only one 272 * instance of that <code>Font</code> is returned in the array, and 273 * other variations must be derived by the application. 274 * <p> 275 * If a font in this environment has multiple programmable variations, 276 * such as Multiple-Master fonts, only one instance of that font is 277 * returned in the <code>Font</code> array. The other variations 278 * must be derived by the application. 279 * 280 * @return an array of <code>Font</code> objects 281 * @see #getAvailableFontFamilyNames 282 * @see java.awt.Font 283 * @see java.awt.Font#deriveFont 284 * @see java.awt.Font#getFontName 285 * @since 1.2 286 */ 287 public abstract Font[] getAllFonts(); 288 289 /** 290 * Returns an array containing the names of all font families in this 291 * <code>GraphicsEnvironment</code> localized for the default locale, 292 * as returned by <code>Locale.getDefault()</code>. 293 * <p> 294 * Typical usage would be for presentation to a user for selection of 295 * a particular family name. An application can then specify this name 296 * when creating a font, in conjunction with a style, such as bold or 297 * italic, giving the font system flexibility in choosing its own best 298 * match among multiple fonts in the same font family. 299 * 300 * @return an array of <code>String</code> containing font family names 301 * localized for the default locale, or a suitable alternative 302 * name if no name exists for this locale. 303 * @see #getAllFonts 304 * @see java.awt.Font 305 * @see java.awt.Font#getFamily 306 * @since 1.2 307 */ 308 public abstract String[] getAvailableFontFamilyNames(); 309 310 /** 311 * Returns an array containing the names of all font families in this 312 * <code>GraphicsEnvironment</code> localized for the specified locale. 313 * <p> 314 * Typical usage would be for presentation to a user for selection of 315 * a particular family name. An application can then specify this name 316 * when creating a font, in conjunction with a style, such as bold or 317 * italic, giving the font system flexibility in choosing its own best 318 * match among multiple fonts in the same font family. 319 * 320 * @param l a {@link Locale} object that represents a 321 * particular geographical, political, or cultural region. 322 * Specifying <code>null</code> is equivalent to 323 * specifying <code>Locale.getDefault()</code>. 324 * @return an array of <code>String</code> containing font family names 325 * localized for the specified <code>Locale</code>, or a 326 * suitable alternative name if no name exists for the specified locale. 327 * @see #getAllFonts 328 * @see java.awt.Font 329 * @see java.awt.Font#getFamily 330 * @since 1.2 331 */ 332 public abstract String[] getAvailableFontFamilyNames(Locale l); 333 334 /** 335 * Registers a <i>created</i> <code>Font</code>in this 336 * <code>GraphicsEnvironment</code>. 337 * A created font is one that was returned from calling 338 * {@link Font#createFont}, or derived from a created font by 339 * calling {@link Font#deriveFont}. 340 * After calling this method for such a font, it is available to 341 * be used in constructing new <code>Font</code>s by name or family name, 342 * and is enumerated by {@link #getAvailableFontFamilyNames} and 343 * {@link #getAllFonts} within the execution context of this 344 * application or applet. This means applets cannot register fonts in 345 * a way that they are visible to other applets. 346 * <p> 347 * Reasons that this method might not register the font and therefore 348 * return <code>false</code> are: 349 * <ul> 350 * <li>The font is not a <i>created</i> <code>Font</code>. 351 * <li>The font conflicts with a non-created <code>Font</code> already 352 * in this <code>GraphicsEnvironment</code>. For example if the name 353 * is that of a system font, or a logical font as described in the 354 * documentation of the {@link Font} class. It is implementation dependent 355 * whether a font may also conflict if it has the same family name 356 * as a system font. 357 * <p>Notice that an application can supersede the registration 358 * of an earlier created font with a new one. 359 * </ul> 360 * @return true if the <code>font</code> is successfully 361 * registered in this <code>GraphicsEnvironment</code>. 362 * @throws NullPointerException if <code>font</code> is null 363 * @since 1.6 364 */ 365 public boolean registerFont(Font font) { 366 if (font == null) { 367 throw new NullPointerException("font cannot be null."); 368 } 369 FontManager fm = FontManagerFactory.getInstance(); 370 return fm.registerFont(font); 371 } 372 373 /** 374 * Indicates a preference for locale-specific fonts in the mapping of 375 * logical fonts to physical fonts. Calling this method indicates that font 376 * rendering should primarily use fonts specific to the primary writing 377 * system (the one indicated by the default encoding and the initial 378 * default locale). For example, if the primary writing system is 379 * Japanese, then characters should be rendered using a Japanese font 380 * if possible, and other fonts should only be used for characters for 381 * which the Japanese font doesn't have glyphs. 382 * <p> 383 * The actual change in font rendering behavior resulting from a call 384 * to this method is implementation dependent; it may have no effect at 385 * all, or the requested behavior may already match the default behavior. 386 * The behavior may differ between font rendering in lightweight 387 * and peered components. Since calling this method requests a 388 * different font, clients should expect different metrics, and may need 389 * to recalculate window sizes and layout. Therefore this method should 390 * be called before user interface initialisation. 391 * @since 1.5 392 */ 393 public void preferLocaleFonts() { 394 FontManager fm = FontManagerFactory.getInstance(); 395 fm.preferLocaleFonts(); 396 } 397 398 /** 399 * Indicates a preference for proportional over non-proportional (e.g. 400 * dual-spaced CJK fonts) fonts in the mapping of logical fonts to 401 * physical fonts. If the default mapping contains fonts for which 402 * proportional and non-proportional variants exist, then calling 403 * this method indicates the mapping should use a proportional variant. 404 * <p> 405 * The actual change in font rendering behavior resulting from a call to 406 * this method is implementation dependent; it may have no effect at all. 407 * The behavior may differ between font rendering in lightweight and 408 * peered components. Since calling this method requests a 409 * different font, clients should expect different metrics, and may need 410 * to recalculate window sizes and layout. Therefore this method should 411 * be called before user interface initialisation. 412 * @since 1.5 413 */ 414 public void preferProportionalFonts() { 415 FontManager fm = FontManagerFactory.getInstance(); 416 fm.preferProportionalFonts(); 417 } 418 419 /** 420 * Returns the Point where Windows should be centered. 421 * It is recommended that centered Windows be checked to ensure they fit 422 * within the available display area using getMaximumWindowBounds(). 423 * @return the point where Windows should be centered 424 * 425 * @exception HeadlessException if isHeadless() returns true 426 * @see #getMaximumWindowBounds 427 * @since 1.4 428 */ 429 public Point getCenterPoint() throws HeadlessException { 430 // Default implementation: return the center of the usable bounds of the 431 // default screen device. 432 Rectangle usableBounds = 433 SunGraphicsEnvironment.getUsableBounds(getDefaultScreenDevice()); 434 return new Point((usableBounds.width / 2) + usableBounds.x, 435 (usableBounds.height / 2) + usableBounds.y); 436 } 437 438 /** 439 * Returns the maximum bounds for centered Windows. 440 * These bounds account for objects in the native windowing system such as 441 * task bars and menu bars. The returned bounds will reside on a single 442 * display with one exception: on multi-screen systems where Windows should 443 * be centered across all displays, this method returns the bounds of the 444 * entire display area. 445 * <p> 446 * To get the usable bounds of a single display, use 447 * <code>GraphicsConfiguration.getBounds()</code> and 448 * <code>Toolkit.getScreenInsets()</code>. 449 * @return the maximum bounds for centered Windows 450 * 451 * @exception HeadlessException if isHeadless() returns true 452 * @see #getCenterPoint 453 * @see GraphicsConfiguration#getBounds 454 * @see Toolkit#getScreenInsets 455 * @since 1.4 456 */ 457 public Rectangle getMaximumWindowBounds() throws HeadlessException { 458 // Default implementation: return the usable bounds of the default screen 459 // device. This is correct for Microsoft Windows and non-Xinerama X11. 460 return SunGraphicsEnvironment.getUsableBounds(getDefaultScreenDevice()); 461 } 462 }