jdk/src/share/classes/java/awt/GraphicsEnvironment.java
changeset 2 90ce3da70b43
child 2372 229b2c88d29c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/awt/GraphicsEnvironment.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,425 @@
+/*
+ * Copyright 1997-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+
+package java.awt;
+
+import java.awt.image.BufferedImage;
+import java.util.Locale;
+import sun.java2d.HeadlessGraphicsEnvironment;
+import sun.java2d.SunGraphicsEnvironment;
+
+/**
+ *
+ * The <code>GraphicsEnvironment</code> class describes the collection
+ * of {@link GraphicsDevice} objects and {@link java.awt.Font} objects
+ * available to a Java(tm) application on a particular platform.
+ * The resources in this <code>GraphicsEnvironment</code> might be local
+ * or on a remote machine.  <code>GraphicsDevice</code> objects can be
+ * screens, printers or image buffers and are the destination of
+ * {@link Graphics2D} drawing methods.  Each <code>GraphicsDevice</code>
+ * has a number of {@link GraphicsConfiguration} objects associated with
+ * it.  These objects specify the different configurations in which the
+ * <code>GraphicsDevice</code> can be used.
+ * @see GraphicsDevice
+ * @see GraphicsConfiguration
+ */
+
+public abstract class GraphicsEnvironment {
+    private static GraphicsEnvironment localEnv;
+
+    /**
+     * The headless state of the Toolkit and GraphicsEnvironment
+     */
+    private static Boolean headless;
+
+    /**
+     * The headless state assumed by default
+     */
+    private static Boolean defaultHeadless;
+
+    /**
+     * This is an abstract class and cannot be instantiated directly.
+     * Instances must be obtained from a suitable factory or query method.
+     */
+    protected GraphicsEnvironment() {
+    }
+
+    /**
+     * Returns the local <code>GraphicsEnvironment</code>.
+     * @return the local <code>GraphicsEnvironment</code>
+     */
+    public static synchronized GraphicsEnvironment getLocalGraphicsEnvironment() {
+        if (localEnv == null) {
+            String nm = (String) java.security.AccessController.doPrivileged
+                (new sun.security.action.GetPropertyAction
+                 ("java.awt.graphicsenv", null));
+
+            try {
+//                      long t0 = System.currentTimeMillis();
+                localEnv =
+                    (GraphicsEnvironment) Class.forName(nm).newInstance();
+//              long t1 = System.currentTimeMillis();
+//              System.out.println("GE creation took " + (t1-t0)+ "ms.");
+                if (isHeadless()) {
+                    localEnv = new HeadlessGraphicsEnvironment(localEnv);
+                }
+            } catch (ClassNotFoundException e) {
+                throw new Error("Could not find class: "+nm);
+            } catch (InstantiationException e) {
+                throw new Error("Could not instantiate Graphics Environment: "
+                                + nm);
+            } catch (IllegalAccessException e) {
+                throw new Error ("Could not access Graphics Environment: "
+                                 + nm);
+            }
+        }
+
+        return localEnv;
+    }
+
+    /**
+     * Tests whether or not a display, keyboard, and mouse can be
+     * supported in this environment.  If this method returns true,
+     * a HeadlessException is thrown from areas of the Toolkit
+     * and GraphicsEnvironment that are dependent on a display,
+     * keyboard, or mouse.
+     * @return <code>true</code> if this environment cannot support
+     * a display, keyboard, and mouse; <code>false</code>
+     * otherwise
+     * @see java.awt.HeadlessException
+     * @since 1.4
+     */
+    public static boolean isHeadless() {
+        return getHeadlessProperty();
+    }
+
+    /**
+     * @return warning message if headless state is assumed by default;
+     * null otherwise
+     * @since 1.5
+     */
+    static String getHeadlessMessage() {
+        if (headless == null) {
+            getHeadlessProperty(); // initialize the values
+        }
+        return defaultHeadless != Boolean.TRUE ? null :
+            "\nNo X11 DISPLAY variable was set, " +
+            "but this program performed an operation which requires it.";
+    }
+
+    /**
+     * @return the value of the property "java.awt.headless"
+     * @since 1.4
+     */
+    private static boolean getHeadlessProperty() {
+        if (headless == null) {
+            java.security.AccessController.doPrivileged(
+            new java.security.PrivilegedAction() {
+                public Object run() {
+                    String nm = System.getProperty("java.awt.headless");
+
+                    if (nm == null) {
+                        /* No need to ask for DISPLAY when run in a browser */
+                        if (System.getProperty("javaplugin.version") != null) {
+                            headless = defaultHeadless = Boolean.FALSE;
+                        } else {
+                            String osName = System.getProperty("os.name");
+                            headless = defaultHeadless =
+                                Boolean.valueOf(("Linux".equals(osName) || "SunOS".equals(osName)) &&
+                                                (System.getenv("DISPLAY") == null));
+                        }
+                    } else if (nm.equals("true")) {
+                        headless = Boolean.TRUE;
+                    } else {
+                        headless = Boolean.FALSE;
+                    }
+                    return null;
+                }
+                }
+            );
+        }
+        return headless.booleanValue();
+    }
+
+    /**
+     * Check for headless state and throw HeadlessException if headless
+     * @since 1.4
+     */
+    static void checkHeadless() throws HeadlessException {
+        if (isHeadless()) {
+            throw new HeadlessException();
+        }
+    }
+
+    /**
+     * Returns whether or not a display, keyboard, and mouse can be
+     * supported in this graphics environment.  If this returns true,
+     * <code>HeadlessException</code> will be thrown from areas of the
+     * graphics environment that are dependent on a display, keyboard, or
+     * mouse.
+     * @return <code>true</code> if a display, keyboard, and mouse
+     * can be supported in this environment; <code>false</code>
+     * otherwise
+     * @see java.awt.HeadlessException
+     * @see #isHeadless
+     * @since 1.4
+     */
+    public boolean isHeadlessInstance() {
+        // By default (local graphics environment), simply check the
+        // headless property.
+        return getHeadlessProperty();
+    }
+
+    /**
+     * Returns an array of all of the screen <code>GraphicsDevice</code>
+     * objects.
+     * @return an array containing all the <code>GraphicsDevice</code>
+     * objects that represent screen devices
+     * @exception HeadlessException if isHeadless() returns true
+     * @see #isHeadless()
+     */
+    public abstract GraphicsDevice[] getScreenDevices()
+        throws HeadlessException;
+
+    /**
+     * Returns the default screen <code>GraphicsDevice</code>.
+     * @return the <code>GraphicsDevice</code> that represents the
+     * default screen device
+     * @exception HeadlessException if isHeadless() returns true
+     * @see #isHeadless()
+     */
+    public abstract GraphicsDevice getDefaultScreenDevice()
+        throws HeadlessException;
+
+    /**
+     * Returns a <code>Graphics2D</code> object for rendering into the
+     * specified {@link BufferedImage}.
+     * @param img the specified <code>BufferedImage</code>
+     * @return a <code>Graphics2D</code> to be used for rendering into
+     * the specified <code>BufferedImage</code>
+     * @throws NullPointerException if <code>img</code> is null
+     */
+    public abstract Graphics2D createGraphics(BufferedImage img);
+
+    /**
+     * Returns an array containing a one-point size instance of all fonts
+     * available in this <code>GraphicsEnvironment</code>.  Typical usage
+     * would be to allow a user to select a particular font.  Then, the
+     * application can size the font and set various font attributes by
+     * calling the <code>deriveFont</code> method on the choosen instance.
+     * <p>
+     * This method provides for the application the most precise control
+     * over which <code>Font</code> instance is used to render text.
+     * If a font in this <code>GraphicsEnvironment</code> has multiple
+     * programmable variations, only one
+     * instance of that <code>Font</code> is returned in the array, and
+     * other variations must be derived by the application.
+     * <p>
+     * If a font in this environment has multiple programmable variations,
+     * such as Multiple-Master fonts, only one instance of that font is
+     * returned in the <code>Font</code> array.  The other variations
+     * must be derived by the application.
+     *
+     * @return an array of <code>Font</code> objects
+     * @see #getAvailableFontFamilyNames
+     * @see java.awt.Font
+     * @see java.awt.Font#deriveFont
+     * @see java.awt.Font#getFontName
+     * @since 1.2
+     */
+    public abstract Font[] getAllFonts();
+
+    /**
+     * Returns an array containing the names of all font families in this
+     * <code>GraphicsEnvironment</code> localized for the default locale,
+     * as returned by <code>Locale.getDefault()</code>.
+     * <p>
+     * Typical usage would be for presentation to a user for selection of
+     * a particular family name. An application can then specify this name
+     * when creating a font, in conjunction with a style, such as bold or
+     * italic, giving the font system flexibility in choosing its own best
+     * match among multiple fonts in the same font family.
+     *
+     * @return an array of <code>String</code> containing font family names
+     * localized for the default locale, or a suitable alternative
+     * name if no name exists for this locale.
+     * @see #getAllFonts
+     * @see java.awt.Font
+     * @see java.awt.Font#getFamily
+     * @since 1.2
+     */
+    public abstract String[] getAvailableFontFamilyNames();
+
+    /**
+     * Returns an array containing the names of all font families in this
+     * <code>GraphicsEnvironment</code> localized for the specified locale.
+     * <p>
+     * Typical usage would be for presentation to a user for selection of
+     * a particular family name. An application can then specify this name
+     * when creating a font, in conjunction with a style, such as bold or
+     * italic, giving the font system flexibility in choosing its own best
+     * match among multiple fonts in the same font family.
+     *
+     * @param l a {@link Locale} object that represents a
+     * particular geographical, political, or cultural region.
+     * Specifying <code>null</code> is equivalent to
+     * specifying <code>Locale.getDefault()</code>.
+     * @return an array of <code>String</code> containing font family names
+     * localized for the specified <code>Locale</code>, or a
+     * suitable alternative name if no name exists for the specified locale.
+     * @see #getAllFonts
+     * @see java.awt.Font
+     * @see java.awt.Font#getFamily
+     * @since 1.2
+     */
+    public abstract String[] getAvailableFontFamilyNames(Locale l);
+
+    /**
+     * Registers a <i>created</i> <code>Font</code>in this
+     * <code>GraphicsEnvironment</code>.
+     * A created font is one that was returned from calling
+     * {@link Font#createFont}, or derived from a created font by
+     * calling {@link Font#deriveFont}.
+     * After calling this method for such a font, it is available to
+     * be used in constructing new <code>Font</code>s by name or family name,
+     * and is enumerated by {@link #getAvailableFontFamilyNames} and
+     * {@link #getAllFonts} within the execution context of this
+     * application or applet. This means applets cannot register fonts in
+     * a way that they are visible to other applets.
+     * <p>
+     * Reasons that this method might not register the font and therefore
+     * return <code>false</code> are:
+     * <ul>
+     * <li>The font is not a <i>created</i> <code>Font</code>.
+     * <li>The font conflicts with a non-created <code>Font</code> already
+     * in this <code>GraphicsEnvironment</code>. For example if the name
+     * is that of a system font, or a logical font as described in the
+     * documentation of the {@link Font} class. It is implementation dependent
+     * whether a font may also conflict if it has the same family name
+     * as a system font.
+     * <p>Notice that an application can supersede the registration
+     * of an earlier created font with a new one.
+     * </ul>
+     * @return true if the <code>font</code> is successfully
+     * registered in this <code>GraphicsEnvironment</code>.
+     * @throws NullPointerException if <code>font</code> is null
+     * @since 1.6
+     */
+    public boolean registerFont(Font font) {
+        if (font == null) {
+            throw new NullPointerException("font cannot be null.");
+        }
+        return sun.font.FontManager.registerFont(font);
+    }
+
+    /**
+     * Indicates a preference for locale-specific fonts in the mapping of
+     * logical fonts to physical fonts. Calling this method indicates that font
+     * rendering should primarily use fonts specific to the primary writing
+     * system (the one indicated by the default encoding and the initial
+     * default locale). For example, if the primary writing system is
+     * Japanese, then characters should be rendered using a Japanese font
+     * if possible, and other fonts should only be used for characters for
+     * which the Japanese font doesn't have glyphs.
+     * <p>
+     * The actual change in font rendering behavior resulting from a call
+     * to this method is implementation dependent; it may have no effect at
+     * all, or the requested behavior may already match the default behavior.
+     * The behavior may differ between font rendering in lightweight
+     * and peered components.  Since calling this method requests a
+     * different font, clients should expect different metrics, and may need
+     * to recalculate window sizes and layout. Therefore this method should
+     * be called before user interface initialisation.
+     * @since 1.5
+     */
+    public void preferLocaleFonts() {
+        sun.font.FontManager.preferLocaleFonts();
+    }
+
+    /**
+     * Indicates a preference for proportional over non-proportional (e.g.
+     * dual-spaced CJK fonts) fonts in the mapping of logical fonts to
+     * physical fonts. If the default mapping contains fonts for which
+     * proportional and non-proportional variants exist, then calling
+     * this method indicates the mapping should use a proportional variant.
+     * <p>
+     * The actual change in font rendering behavior resulting from a call to
+     * this method is implementation dependent; it may have no effect at all.
+     * The behavior may differ between font rendering in lightweight and
+     * peered components. Since calling this method requests a
+     * different font, clients should expect different metrics, and may need
+     * to recalculate window sizes and layout. Therefore this method should
+     * be called before user interface initialisation.
+     * @since 1.5
+     */
+    public void preferProportionalFonts() {
+        sun.font.FontManager.preferProportionalFonts();
+    }
+
+    /**
+     * Returns the Point where Windows should be centered.
+     * It is recommended that centered Windows be checked to ensure they fit
+     * within the available display area using getMaximumWindowBounds().
+     * @return the point where Windows should be centered
+     *
+     * @exception HeadlessException if isHeadless() returns true
+     * @see #getMaximumWindowBounds
+     * @since 1.4
+     */
+    public Point getCenterPoint() throws HeadlessException {
+    // Default implementation: return the center of the usable bounds of the
+    // default screen device.
+        Rectangle usableBounds =
+         SunGraphicsEnvironment.getUsableBounds(getDefaultScreenDevice());
+        return new Point((usableBounds.width / 2) + usableBounds.x,
+                         (usableBounds.height / 2) + usableBounds.y);
+    }
+
+    /**
+     * Returns the maximum bounds for centered Windows.
+     * These bounds account for objects in the native windowing system such as
+     * task bars and menu bars.  The returned bounds will reside on a single
+     * display with one exception: on multi-screen systems where Windows should
+     * be centered across all displays, this method returns the bounds of the
+     * entire display area.
+     * <p>
+     * To get the usable bounds of a single display, use
+     * <code>GraphicsConfiguration.getBounds()</code> and
+     * <code>Toolkit.getScreenInsets()</code>.
+     * @return  the maximum bounds for centered Windows
+     *
+     * @exception HeadlessException if isHeadless() returns true
+     * @see #getCenterPoint
+     * @see GraphicsConfiguration#getBounds
+     * @see Toolkit#getScreenInsets
+     * @since 1.4
+     */
+    public Rectangle getMaximumWindowBounds() throws HeadlessException {
+    // Default implementation: return the usable bounds of the default screen
+    // device.  This is correct for Microsoft Windows and non-Xinerama X11.
+        return SunGraphicsEnvironment.getUsableBounds(getDefaultScreenDevice());
+    }
+}