Java tutorial
/* * Copyright (c) 1997, 2013, Oracle and/or its affiliates. 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. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.awt; import java.awt.geom.AffineTransform; import java.awt.image.BufferedImage; import java.awt.image.ColorModel; import java.awt.image.VolatileImage; import java.awt.image.WritableRaster; import sun.awt.image.SunVolatileImage; /** * The {@code GraphicsConfiguration} class describes the * characteristics of a graphics destination such as a printer or monitor. * There can be many {@code GraphicsConfiguration} objects associated * with a single graphics device, representing different drawing modes or * capabilities. The corresponding native structure will vary from platform * to platform. For example, on X11 windowing systems, * each visual is a different {@code GraphicsConfiguration}. * On Microsoft Windows, {@code GraphicsConfiguration}s represent * PixelFormats available in the current resolution and color depth. * <p> * In a virtual device multi-screen environment in which the desktop * area could span multiple physical screen devices, the bounds of the * {@code GraphicsConfiguration} objects are relative to the * virtual coordinate system. When setting the location of a * component, use {@link #getBounds() getBounds} to get the bounds of * the desired {@code GraphicsConfiguration} and offset the location * with the coordinates of the {@code GraphicsConfiguration}, * as the following code sample illustrates: * </p> * * <pre> * Frame f = new Frame(gc); // where gc is a GraphicsConfiguration * Rectangle bounds = gc.getBounds(); * f.setLocation(10 + bounds.x, 10 + bounds.y); </pre> * * <p> * To determine if your environment is a virtual device * environment, call {@code getBounds} on all of the * {@code GraphicsConfiguration} objects in your system. If * any of the origins of the returned bounds is not (0, 0), * your environment is a virtual device environment. * * <p> * You can also use {@code getBounds} to determine the bounds * of the virtual device. To do this, first call {@code getBounds} on all * of the {@code GraphicsConfiguration} objects in your * system. Then calculate the union of all of the bounds returned * from the calls to {@code getBounds}. The union is the * bounds of the virtual device. The following code sample * calculates the bounds of the virtual device. * * <pre>{@code * Rectangle virtualBounds = new Rectangle(); * GraphicsEnvironment ge = GraphicsEnvironment. * getLocalGraphicsEnvironment(); * GraphicsDevice[] gs = * ge.getScreenDevices(); * for (int j = 0; j < gs.length; j++) { * GraphicsDevice gd = gs[j]; * GraphicsConfiguration[] gc = * gd.getConfigurations(); * for (int i=0; i < gc.length; i++) { * virtualBounds = * virtualBounds.union(gc[i].getBounds()); * } * } }</pre> * * @see Window * @see Frame * @see GraphicsEnvironment * @see GraphicsDevice */ /* * REMIND: What to do about capabilities? * The * capabilities of the device can be determined by enumerating the possible * capabilities and checking if the GraphicsConfiguration * implements the interface for that capability. * */ public abstract class GraphicsConfiguration { private static BufferCapabilities defaultBufferCaps; private static ImageCapabilities defaultImageCaps; /** * This is an abstract class that cannot be instantiated directly. * Instances must be obtained from a suitable factory or query method. * * @see GraphicsDevice#getConfigurations * @see GraphicsDevice#getDefaultConfiguration * @see GraphicsDevice#getBestConfiguration * @see Graphics2D#getDeviceConfiguration */ protected GraphicsConfiguration() { } /** * Returns the {@link GraphicsDevice} associated with this * {@code GraphicsConfiguration}. * @return a {@code GraphicsDevice} object that is * associated with this {@code GraphicsConfiguration}. */ public abstract GraphicsDevice getDevice(); /** * Returns a {@link BufferedImage} with a data layout and color model * compatible with this {@code GraphicsConfiguration}. This * method has nothing to do with memory-mapping * a device. The returned {@code BufferedImage} has * a layout and color model that is closest to this native device * configuration and can therefore be optimally blitted to this * device. * @param width the width of the returned {@code BufferedImage} * @param height the height of the returned {@code BufferedImage} * @return a {@code BufferedImage} whose data layout and color * model is compatible with this {@code GraphicsConfiguration}. */ public BufferedImage createCompatibleImage(int width, int height) { ColorModel model = getColorModel(); WritableRaster raster = model.createCompatibleWritableRaster(width, height); return new BufferedImage(model, raster, model.isAlphaPremultiplied(), null); } /** * Returns a {@code BufferedImage} that supports the specified * transparency and has a data layout and color model * compatible with this {@code GraphicsConfiguration}. This * method has nothing to do with memory-mapping * a device. The returned {@code BufferedImage} has a layout and * color model that can be optimally blitted to a device * with this {@code GraphicsConfiguration}. * @param width the width of the returned {@code BufferedImage} * @param height the height of the returned {@code BufferedImage} * @param transparency the specified transparency mode * @return a {@code BufferedImage} whose data layout and color * model is compatible with this {@code GraphicsConfiguration} * and also supports the specified transparency. * @throws IllegalArgumentException if the transparency is not a valid value * @see Transparency#OPAQUE * @see Transparency#BITMASK * @see Transparency#TRANSLUCENT */ public BufferedImage createCompatibleImage(int width, int height, int transparency) { if (getColorModel().getTransparency() == transparency) { return createCompatibleImage(width, height); } ColorModel cm = getColorModel(transparency); if (cm == null) { throw new IllegalArgumentException("Unknown transparency: " + transparency); } WritableRaster wr = cm.createCompatibleWritableRaster(width, height); return new BufferedImage(cm, wr, cm.isAlphaPremultiplied(), null); } /** * Returns a {@link VolatileImage} with a data layout and color model * compatible with this {@code GraphicsConfiguration}. * The returned {@code VolatileImage} * may have data that is stored optimally for the underlying graphics * device and may therefore benefit from platform-specific rendering * acceleration. * @param width the width of the returned {@code VolatileImage} * @param height the height of the returned {@code VolatileImage} * @return a {@code VolatileImage} whose data layout and color * model is compatible with this {@code GraphicsConfiguration}. * @see Component#createVolatileImage(int, int) * @since 1.4 */ public VolatileImage createCompatibleVolatileImage(int width, int height) { VolatileImage vi = null; try { vi = createCompatibleVolatileImage(width, height, null, Transparency.OPAQUE); } catch (AWTException e) { // shouldn't happen: we're passing in null caps assert false; } return vi; } /** * Returns a {@link VolatileImage} with a data layout and color model * compatible with this {@code GraphicsConfiguration}. * The returned {@code VolatileImage} * may have data that is stored optimally for the underlying graphics * device and may therefore benefit from platform-specific rendering * acceleration. * @param width the width of the returned {@code VolatileImage} * @param height the height of the returned {@code VolatileImage} * @param transparency the specified transparency mode * @return a {@code VolatileImage} whose data layout and color * model is compatible with this {@code GraphicsConfiguration}. * @throws IllegalArgumentException if the transparency is not a valid value * @see Transparency#OPAQUE * @see Transparency#BITMASK * @see Transparency#TRANSLUCENT * @see Component#createVolatileImage(int, int) * @since 1.5 */ public VolatileImage createCompatibleVolatileImage(int width, int height, int transparency) { VolatileImage vi = null; try { vi = createCompatibleVolatileImage(width, height, null, transparency); } catch (AWTException e) { // shouldn't happen: we're passing in null caps assert false; } return vi; } /** * Returns a {@link VolatileImage} with a data layout and color model * compatible with this {@code GraphicsConfiguration}, using * the specified image capabilities. * If the {@code caps} parameter is null, it is effectively ignored * and this method will create a VolatileImage without regard to * {@code ImageCapabilities} constraints. * * The returned {@code VolatileImage} has * a layout and color model that is closest to this native device * configuration and can therefore be optimally blitted to this * device. * @return a {@code VolatileImage} whose data layout and color * model is compatible with this {@code GraphicsConfiguration}. * @param width the width of the returned {@code VolatileImage} * @param height the height of the returned {@code VolatileImage} * @param caps the image capabilities * @exception AWTException if the supplied image capabilities could not * be met by this graphics configuration * @since 1.4 */ public VolatileImage createCompatibleVolatileImage(int width, int height, ImageCapabilities caps) throws AWTException { return createCompatibleVolatileImage(width, height, caps, Transparency.OPAQUE); } /** * Returns a {@link VolatileImage} with a data layout and color model * compatible with this {@code GraphicsConfiguration}, using * the specified image capabilities and transparency value. * If the {@code caps} parameter is null, it is effectively ignored * and this method will create a VolatileImage without regard to * {@code ImageCapabilities} constraints. * * The returned {@code VolatileImage} has * a layout and color model that is closest to this native device * configuration and can therefore be optimally blitted to this * device. * @param width the width of the returned {@code VolatileImage} * @param height the height of the returned {@code VolatileImage} * @param caps the image capabilities * @param transparency the specified transparency mode * @return a {@code VolatileImage} whose data layout and color * model is compatible with this {@code GraphicsConfiguration}. * @see Transparency#OPAQUE * @see Transparency#BITMASK * @see Transparency#TRANSLUCENT * @throws IllegalArgumentException if the transparency is not a valid value * @exception AWTException if the supplied image capabilities could not * be met by this graphics configuration * @see Component#createVolatileImage(int, int) * @since 1.5 */ public VolatileImage createCompatibleVolatileImage(int width, int height, ImageCapabilities caps, int transparency) throws AWTException { VolatileImage vi = new SunVolatileImage(this, width, height, transparency, caps); if (caps != null && caps.isAccelerated() && !vi.getCapabilities().isAccelerated()) { throw new AWTException( "Supplied image capabilities could not " + "be met by this graphics configuration."); } return vi; } /** * Returns the {@link ColorModel} associated with this * {@code GraphicsConfiguration}. * @return a {@code ColorModel} object that is associated with * this {@code GraphicsConfiguration}. */ public abstract ColorModel getColorModel(); /** * Returns the {@code ColorModel} associated with this * {@code GraphicsConfiguration} that supports the specified * transparency. * @param transparency the specified transparency mode * @return a {@code ColorModel} object that is associated with * this {@code GraphicsConfiguration} and supports the * specified transparency or null if the transparency is not a valid * value. * @see Transparency#OPAQUE * @see Transparency#BITMASK * @see Transparency#TRANSLUCENT */ public abstract ColorModel getColorModel(int transparency); /** * Returns the default {@link AffineTransform} for this * {@code GraphicsConfiguration}. This * {@code AffineTransform} is typically the Identity transform * for most normal screens. The default {@code AffineTransform} * maps coordinates onto the device such that 72 user space * coordinate units measure approximately 1 inch in device * space. The normalizing transform can be used to make * this mapping more exact. Coordinates in the coordinate space * defined by the default {@code AffineTransform} for screen and * printer devices have the origin in the upper left-hand corner of * the target region of the device, with X coordinates * increasing to the right and Y coordinates increasing downwards. * For image buffers not associated with a device, such as those not * created by {@code createCompatibleImage}, * this {@code AffineTransform} is the Identity transform. * @return the default {@code AffineTransform} for this * {@code GraphicsConfiguration}. */ public abstract AffineTransform getDefaultTransform(); /** * Returns an {@code AffineTransform} that can be concatenated * with the default {@code AffineTransform} * of a {@code GraphicsConfiguration} so that 72 units in user * space equals 1 inch in device space. * <p> * For a particular {@link Graphics2D}, g, one * can reset the transformation to create * such a mapping by using the following pseudocode: * <pre> * GraphicsConfiguration gc = g.getDeviceConfiguration(); * * g.setTransform(gc.getDefaultTransform()); * g.transform(gc.getNormalizingTransform()); * </pre> * Note that sometimes this {@code AffineTransform} is identity, * such as for printers or metafile output, and that this * {@code AffineTransform} is only as accurate as the information * supplied by the underlying system. For image buffers not * associated with a device, such as those not created by * {@code createCompatibleImage}, this * {@code AffineTransform} is the Identity transform * since there is no valid distance measurement. * @return an {@code AffineTransform} to concatenate to the * default {@code AffineTransform} so that 72 units in user * space is mapped to 1 inch in device space. */ public abstract AffineTransform getNormalizingTransform(); /** * Returns the bounds of the {@code GraphicsConfiguration} * in the device coordinates. In a multi-screen environment * with a virtual device, the bounds can have negative X * or Y origins. * @return the bounds of the area covered by this * {@code GraphicsConfiguration}. * @since 1.3 */ public abstract Rectangle getBounds(); private static class DefaultBufferCapabilities extends BufferCapabilities { public DefaultBufferCapabilities(ImageCapabilities imageCaps) { super(imageCaps, imageCaps, null); } } /** * Returns the buffering capabilities of this * {@code GraphicsConfiguration}. * @return the buffering capabilities of this graphics * configuration object * @since 1.4 */ public BufferCapabilities getBufferCapabilities() { if (defaultBufferCaps == null) { defaultBufferCaps = new DefaultBufferCapabilities(getImageCapabilities()); } return defaultBufferCaps; } /** * Returns the image capabilities of this * {@code GraphicsConfiguration}. * @return the image capabilities of this graphics * configuration object * @since 1.4 */ public ImageCapabilities getImageCapabilities() { if (defaultImageCaps == null) { defaultImageCaps = new ImageCapabilities(false); } return defaultImageCaps; } /** * Returns whether this {@code GraphicsConfiguration} supports * the {@link GraphicsDevice.WindowTranslucency#PERPIXEL_TRANSLUCENT * PERPIXEL_TRANSLUCENT} kind of translucency. * * @return whether the given GraphicsConfiguration supports * the translucency effects. * * @see Window#setBackground(Color) * * @since 1.7 */ public boolean isTranslucencyCapable() { // Overridden in subclasses return false; } }