java/awt/GraphicsConfiguration.java

/* GraphicsConfiguration.java -- describes characteristics of graphics
   Copyright (C) 2000, 2001, 2002 Free Software Foundation

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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02110-1301 USA.

Linking this library statically or dynamically with other modules is
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permission to link this library with independent modules to produce an
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package java.awt;

import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.VolatileImage;

/**
 * This class describes the configuration of various graphics devices, such
 * as a monitor or printer. Different configurations may exist for the same
 * device, according to the different native modes supported.
 *
 * <p>Virtual devices are supported (for example, in a multiple screen
 * environment, a virtual device covers all screens simultaneously); the
 * configuration will have a non-zero relative coordinate system in such
 * a case.
 *
 * @author Eric Blake (ebb9@email.byu.edu)
 * @see Window
 * @see Frame
 * @see GraphicsEnvironment
 * @see GraphicsDevice
 * @since 1.0
 * @status updated to 1.4
 */
public abstract class GraphicsConfiguration
{

  /** The cached image capabilities. */
  private ImageCapabilities imageCapabilities;

  /** The cached buffer capabilities. */
  private BufferCapabilities bufferCapabilities;

  /**
   * The default constructor.
   *
   * @see GraphicsDevice#getConfigurations()
   * @see GraphicsDevice#getDefaultConfiguration()
   * @see GraphicsDevice#getBestConfiguration(GraphicsConfigTemplate)
   * @see Graphics2D#getDeviceConfiguration()
   */
  protected GraphicsConfiguration ()
  {
  }

  /**
   * Gets the associated device that this configuration describes.
   *
   * @return the device
   */
  public abstract GraphicsDevice getDevice();

  /**
   * Returns a buffered image optimized to this device, so that blitting can
   * be supported in the buffered image.
   *
   * @param w the width of the buffer
   * @param h the height of the buffer
   * @return the buffered image, or null if none is supported
   */
  public abstract BufferedImage createCompatibleImage(int w, int h);

  /**
   * Returns a buffered volatile image optimized to this device, so that
   * blitting can be supported in the buffered image. Because the buffer is
   * volatile, it can be optimized by native graphics accelerators.
   *
   * @param w the width of the buffer
   * @param h the height of the buffer
   * @return the buffered image, or null if none is supported
   * @see Component#createVolatileImage(int, int)
   * @since 1.4
   */
  public abstract VolatileImage createCompatibleVolatileImage(int w, int h);

  /**
   * Returns a buffered volatile image optimized to this device, and with the
   * given capabilities, so that blitting can be supported in the buffered
   * image. Because the buffer is volatile, it can be optimized by native
   * graphics accelerators.
   *
   * @param w the width of the buffer
   * @param h the height of the buffer
   * @param caps the desired capabilities of the image buffer
   * @return the buffered image, or null if none is supported
   * @throws AWTException if the capabilities cannot be met
   * @since 1.4
   */
  public VolatileImage createCompatibleVolatileImage(int w, int h,
                                                     ImageCapabilities caps)
    throws AWTException
  {
    // Must be overridden by implementations to check caps.
    return createCompatibleVolatileImage(w, h);
  }

  /**
   * Returns a buffered volatile image optimized to this device, and
   * with the given transparency. Because the buffer is volatile, it
   * can be optimized by native graphics accelerators.
   *
   * @param width the width of the buffer
   * @param height the height of the buffer
   * @param transparency the transparency value for the buffer
   * @return the buffered image, or null if none is supported
   * @since 1.5
   */
  public abstract VolatileImage createCompatibleVolatileImage(int width,
                                                              int height,
                                                              int transparency);

  /**
   * Creates a volatile image with the specified capabilities and transparency.
   * If the backend cannot meet the requested capabilities and transparency,
   * an AWTException is thrown.
   *
   * @param width the width of the image
   * @param height the height of the image
   * @param caps the requested capabilities
   * @param transparency the required transparency
   *
   * @return a volatile image with the specified capabilites and transparency
   *
   * @throws AWTException if the required capabilities and transparency cannot
   *         be met
   *
   * @since 1.5
   */
  public VolatileImage createCompatibleVolatileImage(int width, int height,
                                                     ImageCapabilities caps,
                                                     int transparency)
    throws AWTException
  {
    // Must be overridden by implementations to check caps.
    return createCompatibleVolatileImage(width, height, transparency);
  }

  /**
   * Returns a buffered image optimized to this device, and with the specified
   * transparency, so that blitting can be supported in the buffered image.
   *
   * @param w the width of the buffer
   * @param h the height of the buffer
   * @param transparency the transparency of the buffer
   * @return the buffered image, or null if none is supported
   * @see Transparency#OPAQUE
   * @see Transparency#BITMASK
   * @see Transparency#TRANSLUCENT
   */
  public abstract BufferedImage createCompatibleImage(int w, int h,
                                                      int transparency);

  /**
   * Gets the color model of the corresponding device.
   *
   * @return the color model
   */
  public abstract ColorModel getColorModel();

  /**
   * Gets a color model for the corresponding device which supports the desired
   * transparency level.
   *
   * @param transparency the transparency of the model
   * @return the color model, with transparency
   * @see Transparency#OPAQUE
   * @see Transparency#BITMASK
   * @see Transparency#TRANSLUCENT
   */
  public abstract ColorModel getColorModel(int transparency);

  /**
   * Returns a transform that maps user coordinates to device coordinates. The
   * preferred mapping is about 72 user units to 1 inch (2.54 cm) of physical
   * space. This is often the identity transform. The device coordinates have
   * the origin at the upper left, with increasing x to the right, and
   * increasing y to the bottom.
   *
   * @return the transformation from user space to device space
   * @see #getNormalizingTransform()
   */
  public abstract AffineTransform getDefaultTransform();

  /**
   * Returns a transform that maps user coordinates to device coordinates. The
   * exact mapping is 72 user units to 1 inch (2.54 cm) of physical space.
   * This is often the identity transform. The device coordinates have the
   * origin at the upper left, with increasing x to the right, and increasing
   * y to the bottom. Note that this is more accurate (and thus, sometimes more
   * costly) than the default transform.
   *
   * @return the normalized transformation from user space to device space
   * @see #getDefaultTransform()
   */
  public abstract AffineTransform getNormalizingTransform();

  /**
   * Returns the bounds of the configuration, in device coordinates. If this
   * is a virtual device (for example, encompassing several screens), the
   * bounds may have a non-zero origin.
   *
   * @return the device bounds
   * @since 1.3
   */
  public abstract Rectangle getBounds();

  /**
   * Returns the buffering capabilities of this configuration.
   *
   * @return the buffer capabilities
   * @since 1.4
   */
  public BufferCapabilities getBufferCapabilities()
  {
    if (imageCapabilities == null)
      getImageCapabilities();

    if (bufferCapabilities == null)
      bufferCapabilities = new BufferCapabilities(imageCapabilities,
                                                  imageCapabilities, null);
    return bufferCapabilities;
  }

  /**
   * Returns the imaging capabilities of this configuration.
   *
   * @return the image capabilities
   * @since 1.4
   */
  public ImageCapabilities getImageCapabilities()
  {
    if (imageCapabilities == null)
      imageCapabilities = new ImageCapabilities(false);
    return imageCapabilities;
  }
} // class GraphicsConfiguration