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package java.awt;


Capabilities and properties of buffers.

Author:Michael Martak
See Also:
Since:1.4
/**
 * Capabilities and properties of buffers.
 *
 * @see java.awt.image.BufferStrategy#getCapabilities()
 * @see GraphicsConfiguration#getBufferCapabilities
 * @author Michael Martak
 * @since 1.4
 */
public class BufferCapabilities implements Cloneable {

    private ImageCapabilities frontCaps;
    private ImageCapabilities backCaps;
    private FlipContents flipContents;

    
Creates a new object for specifying buffering capabilities

Params:
  • frontCaps – the capabilities of the front buffer; cannot be
null
  • backCaps – the capabilities of the back and intermediate buffers;
cannot be null
  • flipContents – the contents of the back buffer after page-flipping,
null if page flipping is not used (implies blitting)
Throws:
/**
     * Creates a new object for specifying buffering capabilities
     * @param frontCaps the capabilities of the front buffer; cannot be
     * <code>null</code>
     * @param backCaps the capabilities of the back and intermediate buffers;
     * cannot be <code>null</code>
     * @param flipContents the contents of the back buffer after page-flipping,
     * <code>null</code> if page flipping is not used (implies blitting)
     * @exception IllegalArgumentException if frontCaps or backCaps are
     * <code>null</code>
     */
    public BufferCapabilities(ImageCapabilities frontCaps,
        ImageCapabilities backCaps, FlipContents flipContents) {
        if (frontCaps == null || backCaps == null) {
            throw new IllegalArgumentException(
                "Image capabilities specified cannot be null");
        }
        this.frontCaps = frontCaps;
        this.backCaps = backCaps;
        this.flipContents = flipContents;
    }

    
Returns:the image capabilities of the front (displayed) buffer
/**
     * @return the image capabilities of the front (displayed) buffer
     */
    public ImageCapabilities getFrontBufferCapabilities() {
        return frontCaps;
    }

    
Returns:the image capabilities of all back buffers (intermediate buffers
are considered back buffers)
/**
     * @return the image capabilities of all back buffers (intermediate buffers
     * are considered back buffers)
     */
    public ImageCapabilities getBackBufferCapabilities() {
        return backCaps;
    }

    
Returns:whether or not the buffer strategy uses page flipping; a set of
buffers that uses page flipping
can swap the contents internally between the front buffer and one or
more back buffers by switching the video pointer (or by copying memory
internally).  A non-flipping set of
buffers uses blitting to copy the contents from one buffer to
another; when this is the case, getFlipContents returns
null
/**
     * @return whether or not the buffer strategy uses page flipping; a set of
     * buffers that uses page flipping
     * can swap the contents internally between the front buffer and one or
     * more back buffers by switching the video pointer (or by copying memory
     * internally).  A non-flipping set of
     * buffers uses blitting to copy the contents from one buffer to
     * another; when this is the case, <code>getFlipContents</code> returns
     * <code>null</code>
     */
    public boolean isPageFlipping() {
        return (getFlipContents() != null);
    }

    
See Also:
Returns:the resulting contents of the back buffer after page-flipping.
This value is null when the isPageFlipping
returns false, implying blitting.  It can be one of
FlipContents.UNDEFINED
(the assumed default), FlipContents.BACKGROUND,
FlipContents.PRIOR, or
FlipContents.COPIED.
/**
     * @return the resulting contents of the back buffer after page-flipping.
     * This value is <code>null</code> when the <code>isPageFlipping</code>
     * returns <code>false</code>, implying blitting.  It can be one of
     * <code>FlipContents.UNDEFINED</code>
     * (the assumed default), <code>FlipContents.BACKGROUND</code>,
     * <code>FlipContents.PRIOR</code>, or
     * <code>FlipContents.COPIED</code>.
     * @see #isPageFlipping
     * @see FlipContents#UNDEFINED
     * @see FlipContents#BACKGROUND
     * @see FlipContents#PRIOR
     * @see FlipContents#COPIED
     */
    public FlipContents getFlipContents() {
        return flipContents;
    }

    
See Also:
Returns:whether page flipping is only available in full-screen mode.  If this
is true, full-screen exclusive mode is required for
page-flipping.
/**
     * @return whether page flipping is only available in full-screen mode.  If this
     * is <code>true</code>, full-screen exclusive mode is required for
     * page-flipping.
     * @see #isPageFlipping
     * @see GraphicsDevice#setFullScreenWindow
     */
    public boolean isFullScreenRequired() {
        return false;
    }

    
See Also:
Returns:whether or not
page flipping can be performed using more than two buffers (one or more
intermediate buffers as well as the front and back buffer).
/**
     * @return whether or not
     * page flipping can be performed using more than two buffers (one or more
     * intermediate buffers as well as the front and back buffer).
     * @see #isPageFlipping
     */
    public boolean isMultiBufferAvailable() {
        return false;
    }

    
Returns:a copy of this BufferCapabilities object.
/**
     * @return a copy of this BufferCapabilities object.
     */
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            // Since we implement Cloneable, this should never happen
            throw new InternalError(e);
        }
    }

    // Inner class FlipContents
    
A type-safe enumeration of the possible back buffer contents after
page-flipping

Since:1.4
/**
     * A type-safe enumeration of the possible back buffer contents after
     * page-flipping
     * @since 1.4
     */
    public static final class FlipContents extends AttributeValue {

        private static int I_UNDEFINED = 0;
        private static int I_BACKGROUND = 1;
        private static int I_PRIOR = 2;
        private static int I_COPIED = 3;

        private static final String NAMES[] =
            { "undefined", "background", "prior", "copied" };

        
When flip contents are UNDEFINED, the
contents of the back buffer are undefined after flipping.

See Also:
/**
         * When flip contents are <code>UNDEFINED</code>, the
         * contents of the back buffer are undefined after flipping.
         * @see #isPageFlipping
         * @see #getFlipContents
         * @see #BACKGROUND
         * @see #PRIOR
         * @see #COPIED
         */
        public static final FlipContents UNDEFINED =
            new FlipContents(I_UNDEFINED);

        
When flip contents are BACKGROUND, the
contents of the back buffer are cleared with the background color after
flipping.

See Also:
/**
         * When flip contents are <code>BACKGROUND</code>, the
         * contents of the back buffer are cleared with the background color after
         * flipping.
         * @see #isPageFlipping
         * @see #getFlipContents
         * @see #UNDEFINED
         * @see #PRIOR
         * @see #COPIED
         */
        public static final FlipContents BACKGROUND =
            new FlipContents(I_BACKGROUND);

        
When flip contents are PRIOR, the
contents of the back buffer are the prior contents of the front buffer
(a true page flip).

See Also:
/**
         * When flip contents are <code>PRIOR</code>, the
         * contents of the back buffer are the prior contents of the front buffer
         * (a true page flip).
         * @see #isPageFlipping
         * @see #getFlipContents
         * @see #UNDEFINED
         * @see #BACKGROUND
         * @see #COPIED
         */
        public static final FlipContents PRIOR =
            new FlipContents(I_PRIOR);

        
When flip contents are COPIED, the
contents of the back buffer are copied to the front buffer when
flipping.

See Also:
/**
         * When flip contents are <code>COPIED</code>, the
         * contents of the back buffer are copied to the front buffer when
         * flipping.
         * @see #isPageFlipping
         * @see #getFlipContents
         * @see #UNDEFINED
         * @see #BACKGROUND
         * @see #PRIOR
         */
        public static final FlipContents COPIED =
            new FlipContents(I_COPIED);

        private FlipContents(int type) {
            super(type, NAMES);
        }

    } // Inner class FlipContents

}