https://openjdk.java.net/ 
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package sun.swing;

import javax.swing.JComponent;
import java.awt.Component;
import java.awt.Cursor;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragGestureRecognizer;
import java.awt.dnd.DragSource;
import java.awt.dnd.DropTarget;
import java.awt.dnd.InvalidDnDOperationException;
import java.awt.dnd.peer.DragSourceContextPeer;


The interface by means of which the JLightweightFrame class communicates to its client application. 
 The client application implements this interface so it can response to requests and process notifications from JLightweightFrame. An implementation of this interface is associated with a 
JLightweightFrame instance via the JLightweightFrame.setContent method. A hierarchy of components contained in the JComponent instance returned by the getComponent method should not contain any heavyweight components, otherwise JLightweightFrame may fail to paint it. 
Author:Artem Ananiev, Anton Tarasov, Jim Graham
/**
 * The interface by means of which the {@link JLightweightFrame} class
 * communicates to its client application.
 * <p>
 * The client application implements this interface so it can response
 * to requests and process notifications from {@code JLightweightFrame}.
 * An implementation of this interface is associated with a {@code
 * JLightweightFrame} instance via the {@link JLightweightFrame#setContent}
 * method.
 *
 * A hierarchy of components contained in the {@code JComponent} instance
 * returned by the {@link #getComponent} method should not contain any
 * heavyweight components, otherwise {@code JLightweightFrame} may fail
 * to paint it.
 *
 * @author Artem Ananiev
 * @author Anton Tarasov
 * @author Jim Graham
 */
public interface LightweightContent {

    
The client application overrides this method to return the 
JComponent instance which the JLightweightFrame container will paint as its lightweight content. A hierarchy of components contained in this component should not contain any heavyweight objects. 
Returns:the component to paint
/**
     * The client application overrides this method to return the {@code
     * JComponent} instance which the {@code JLightweightFrame} container
     * will paint as its lightweight content. A hierarchy of components
     * contained in this component should not contain any heavyweight objects.
     *
     * @return the component to paint
     */
    public JComponent getComponent();

    
JLightweightFrame calls this method to notify the client application that it acquires the paint lock. The client application should implement the locking mechanism in order to synchronize access to the content image data, shared between JLightweightFrame and the client application. 
See Also:
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that it acquires the paint lock. The client application
     * should implement the locking mechanism in order to synchronize access
     * to the content image data, shared between {@code JLightweightFrame}
     * and the client application.
     *
     * @see #paintUnlock
     */
    public void paintLock();

    
JLightweightFrame calls this method to notify the client application that it releases the paint lock. The client application should implement the locking mechanism in order to synchronize access to the content image data, shared between JLightweightFrame and the client application. 
See Also:
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that it releases the paint lock. The client application
     * should implement the locking mechanism in order to synchronize access
     * to the content image data, shared between {@code JLightweightFrame}
     * and the client application.
     *
     * @see #paintLock
     */
    public void paintUnlock();

    
JLightweightFrame calls this method to notify the client application that a new data buffer has been set as a content pixel buffer. Typically this occurs when a buffer of a larger size is created in response to a content resize event. 
 The method reports a reference to the pixel data buffer, the content image bounds within the buffer and the line stride of the buffer. These values have the following correlation. The width and height matches the layout size of the content (the component returned from the getComponent method). The x and y is the origin of the content, (0, 0) in the layout coordinate space of the content, appearing at data[y * scale * linestride + x * scale] in the buffer. A pixel with indices (i, j), where (0 <= i < width) and (0 <= j < height), in the layout coordinate space of the content is represented by a scale^2 square of pixels in the physical coordinate space of the buffer. The top-left corner of the square has the following physical coordinate in the buffer: data[(y + j) * scale * linestride + (x + i) * scale]. 
Params:
  • data – the content pixel data buffer of INT_ARGB_PRE type
  • x – the logical x coordinate of the image
  • y – the logical y coordinate of the image
  • width – the logical width of the image
  • height – the logical height of the image
  • linestride – the line stride of the pixel buffer
  • scale – the scale factor of the pixel buffer
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that a new data buffer has been set as a content pixel
     * buffer. Typically this occurs when a buffer of a larger size is
     * created in response to a content resize event.
     * <p>
     * The method reports a reference to the pixel data buffer, the content
     * image bounds within the buffer and the line stride of the buffer.
     * These values have the following correlation.
     * The {@code width} and {@code height} matches the layout size of the content
     * (the component returned from the {@link #getComponent} method). The
     * {@code x} and {@code y} is the origin of the content, {@code (0, 0)}
     * in the layout coordinate space of the content, appearing at
     * {@code data[y * scale * linestride + x * scale]} in the buffer.
     * A pixel with indices {@code (i, j)}, where {@code (0 <= i < width)} and
     * {@code (0 <= j < height)}, in the layout coordinate space of the content
     * is represented by a {@code scale^2} square of pixels in the physical
     * coordinate space of the buffer. The top-left corner of the square has the
     * following physical coordinate in the buffer:
     * {@code data[(y + j) * scale * linestride + (x + i) * scale]}.
     *
     * @param data the content pixel data buffer of INT_ARGB_PRE type
     * @param x the logical x coordinate of the image
     * @param y the logical y coordinate of the image
     * @param width the logical width of the image
     * @param height the logical height of the image
     * @param linestride the line stride of the pixel buffer
     * @param scale the scale factor of the pixel buffer
     */
    default public void imageBufferReset(int[] data,
                                 int x, int y,
                                 int width, int height,
                                 int linestride,
                                 int scale)
    {
        imageBufferReset(data, x, y, width, height, linestride);
    }

    
The default implementation for #imageBufferReset uses a hard-coded value
of 1 for the scale factor. Both the old and the new methods provide
default implementations in order to allow a client application to run
with any JDK version without breaking backward compatibility.

/**
     * The default implementation for #imageBufferReset uses a hard-coded value
     * of 1 for the scale factor. Both the old and the new methods provide
     * default implementations in order to allow a client application to run
     * with any JDK version without breaking backward compatibility.
     */
    default public void imageBufferReset(int[] data,
                                 int x, int y,
                                 int width, int height,
                                 int linestride)
    {
        imageBufferReset(data, x, y, width, height, linestride, 1);
    }

    
JLightweightFrame calls this method to notify the client application that the content image bounds have been changed within the image's pixel buffer. 
Params:
  • x – the x coordinate of the image
  • y – the y coordinate of the image
  • width – the width of the image
  • height – the height of the image
See Also:
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content image bounds have been changed within the
     * image's pixel buffer.
     *
     * @param x the x coordinate of the image
     * @param y the y coordinate of the image
     * @param width the width of the image
     * @param height the height of the image
     *
     * @see #imageBufferReset
     */
    public void imageReshaped(int x, int y, int width, int height);

    
JLightweightFrame calls this method to notify the client application that a part of the content image, or the whole image has been updated. The method reports bounds of the rectangular dirty region. The dirtyX and dirtyY is the origin of the dirty rectangle, which is relative to the origin of the content, appearing at data[(y + dirtyY] * linestride + (x + dirtyX)] in the pixel buffer (see imageBufferReset). All indices data[(y + dirtyY + j) * linestride + (x + dirtyX + i)] where (0 <= i < dirtyWidth) and (0 <= j < dirtyHeight) will represent valid pixel data, (i, j) in the coordinate space of the dirty rectangle. 
Params:
  • dirtyX – the x coordinate of the dirty rectangle,
       relative to the image origin
  • dirtyY – the y coordinate of the dirty rectangle,
       relative to the image origin
  • dirtyWidth – the width of the dirty rectangle
  • dirtyHeight – the height of the dirty rectangle
See Also:
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that a part of the content image, or the whole image has
     * been updated. The method reports bounds of the rectangular dirty region.
     * The {@code dirtyX} and {@code dirtyY} is the origin of the dirty
     * rectangle, which is relative to the origin of the content, appearing
     * at {@code data[(y + dirtyY] * linestride + (x + dirtyX)]} in the pixel
     * buffer (see {@link #imageBufferReset}). All indices
     * {@code data[(y + dirtyY + j) * linestride + (x + dirtyX + i)]} where
     * {@code (0 <= i < dirtyWidth)} and {@code (0 <= j < dirtyHeight)}
     * will represent valid pixel data, {@code (i, j)} in the coordinate space
     * of the dirty rectangle.
     *
     * @param dirtyX the x coordinate of the dirty rectangle,
     *        relative to the image origin
     * @param dirtyY the y coordinate of the dirty rectangle,
     *        relative to the image origin
     * @param dirtyWidth the width of the dirty rectangle
     * @param dirtyHeight the height of the dirty rectangle
     *
     * @see #imageBufferReset
     * @see #imageReshaped
     */
    public void imageUpdated(int dirtyX, int dirtyY,
                             int dirtyWidth, int dirtyHeight);

    
JLightweightFrame calls this method to notify the client application that the frame has grabbed focus. 
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the frame has grabbed focus.
     */
    public void focusGrabbed();

    
JLightweightFrame calls this method to notify the client application that the frame has ungrabbed focus. 
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the frame has ungrabbed focus.
     */
    public void focusUngrabbed();

    
JLightweightFrame calls this method to notify the client application that the content preferred size has changed. 
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content preferred size has changed.
     */
    public void preferredSizeChanged(int width, int height);

    
JLightweightFrame calls this method to notify the client application that the content maximum size has changed. 
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content maximum size has changed.
     */
    public void maximumSizeChanged(int width, int height);

    
JLightweightFrame calls this method to notify the client application that the content minimum size has changed. 
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that the content minimum size has changed.
     */
    public void minimumSizeChanged(int width, int height);

    
JLightweightFrame calls this method to notify the client application that in needs to set a cursor 
Params:
  • cursor – a cursor to set
/**
     * {@code JLightweightFrame} calls this method to notify the client
     * application that in needs to set a cursor
     * @param cursor a cursor to set
     */
    default public void setCursor(Cursor cursor) { }

    
Create a drag gesture recognizer for the lightweight frame.

/**
     * Create a drag gesture recognizer for the lightweight frame.
     */
    default public <T extends DragGestureRecognizer> T createDragGestureRecognizer(
            Class<T> abstractRecognizerClass,
            DragSource ds, Component c, int srcActions,
            DragGestureListener dgl)
    {
        return null;
    }

    
Create a drag source context peer for the lightweight frame.

/**
     * Create a drag source context peer for the lightweight frame.
     */
    default public DragSourceContextPeer createDragSourceContextPeer(DragGestureEvent dge) throws InvalidDnDOperationException
    {
        return null;
    }

    
Adds a drop target to the lightweight frame.

/**
     * Adds a drop target to the lightweight frame.
     */
    default public void addDropTarget(DropTarget dt) {}

    
Removes a drop target from the lightweight frame.

/**
     * Removes a drop target from the lightweight frame.
     */
    default public void removeDropTarget(DropTarget dt) {}
}