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Class com.sun.java.swing.JViewport

java.lang.Object
   |
   +----java.awt.Component
           |
           +----java.awt.Container
                   |
                   +----com.sun.java.swing.JComponent
                           |
                           +----com.sun.java.swing.JViewport

public class JViewport

extends JComponent

backingStore

backingStoreGraphics

backingStoreImage

changeEvent

changeListener

isViewSizeSet

lastPaintPosition

The last viewPosition that we've painted, so we know how much of the backing store image is valid.

scrollUnderway

viewListener

JViewport()

add(Component)

Sets the Viewports one lightweight child, x can be null.

addChangeListener(ChangeListener)

ChangeListeners are notified whenever the views position or extent size changes.

computeBlit(Point, Point, Point, Point, Dimension, Rectangle)

Computes the parameters for a blit where the backing store image currently contains oldLoc in the upper left hand corner and we're scrolling to newLoc.

createLayoutManager()

Subclassers can override this to install a different layout manager (or null) in the constructor.

createViewListener()

getExtentSize()

Returns the size of the visible part of the view in view coordinates.

getInsets()

The viewport "scrolls" it's child (called the "view") by the normal parent/child clipping (typically the view is moved in the opposite direction of the scroll).

getView()

Returns the Viewports one child or null.

getViewPosition()

Returns the view coordinates that appear in the upper left hand corner of the viewport, 0,0 if there's no view.

getViewSize()

If the views size hasn't been explicitly set return the preferred size, otherwise return the views current size.

isBackingStoreEnabled()

Returns true if this viewport is maintaining an offscreen image of its contents.

paint(Graphics)

If backingStore is enabled, paint to the backingStore Image and blit that to the screen.

remove(Component)

removeChangeListener(ChangeListener)

repaint(long, int, int, int, int)

If we're in the middle of a setViewPosition() call and backingStore is turned on, then attempt to blit the common part of the old view and the new one.

scrollRectToVisible(Rectangle)

Overridden to scroll the View such that aRect within the View becomes visible.

setBackingStoreEnabled(boolean)

If true if this viewport will maintain an offscreen image of its contents.

setBounds(int, int, int, int)

setExtentSize(Dimension)

Set the size of the visible part of the view, newExtent is in view coordinates.

setView(Component)

Sets the Viewports one lightweight child, x can be null.

setViewPosition(Point)

Sets the view coordinates that appear in the upper left hand corner of the viewport, null if there's no view.

setViewSize(Dimension)

Sets the view coordinates that appear in the upper left hand corner of the viewport, null if there's no view.

toViewCoordinates(Dimension)

Convert a size in pixel coordinates to view coordinates.

toViewCoordinates(Point)

Convert a point in pixel coordinates to view coordinates.

 protected boolean isViewSizeSet

 protected Point lastPaintPosition

The last viewPosition that we've painted, so we know how much of the backing store image is valid.

 protected boolean backingStore

 protected Image backingStoreImage

 protected Graphics backingStoreGraphics

 protected boolean scrollUnderway

 protected ComponentListener viewListener

 protected ChangeListener changeListener

 protected ChangeEvent changeEvent

 public JViewport()

 public Component add(Component x)

Sets the Viewports one lightweight child, x can be null.

Overrides:

add in class Container

See Also:

setView.

 public void remove(Component x)

Overrides:

remove in class Container

 public void scrollRectToVisible(Rectangle contentRect)

Overridden to scroll the View such that aRect within the View becomes visible.

Overrides:

scrollRectToVisible in class JComponent

 public final Insets getInsets()

The viewport "scrolls" it's child (called the "view") by the normal parent/child clipping (typically the view is moved in the opposite direction of the scroll). Non-zero insets aren't possible without introducing an extra container.

Overrides:

getInsets in class JComponent

 public void paint(Graphics g)

If backingStore is enabled, paint to the backingStore Image and blit that to the screen.

Overrides:

paint in class JComponent

 public void setBounds(int x,
                       int y,
                       int w,
                       int h)

Overrides:

setBounds in class JComponent

 public boolean isBackingStoreEnabled()

Returns true if this viewport is maintaining an offscreen image of its contents.

 public void setBackingStoreEnabled(boolean x)

If true if this viewport will maintain an offscreen image of its contents. The image is used to reduce the cost of small one dimensional changes to the viewPosition. Rather than repainting the entire viewport we use Graphics.copyArea() to effect some of the scroll.

 public Component getView()

Returns the Viewports one child or null.

 public void setView(Component x)

Sets the Viewports one lightweight child, x can be null.

 public Dimension getViewSize()

If the views size hasn't been explicitly set return the preferred size, otherwise return the views current size. If there's no view return 0,0.

 public void setViewSize(Dimension newSize)

Sets the view coordinates that appear in the upper left hand corner of the viewport, null if there's no view.

 public Point getViewPosition()

Returns the view coordinates that appear in the upper left hand corner of the viewport, 0,0 if there's no view.

 public void setViewPosition(Point p)

Sets the view coordinates that appear in the upper left hand corner of the viewport, null if there's no view.

 public void repaint(long t,
                     int x,
                     int y,
                     int w,
                     int h)

If we're in the middle of a setViewPosition() call and backingStore is turned on, then attempt to blit the common part of the old view and the new one.

Overrides:

repaint in class JComponent

 protected boolean computeBlit(Point oldLoc,
                               Point newLoc,
                               Point blitFrom,
                               Point blitTo,
                               Dimension blitSize,
                               Rectangle blitPaint)

Computes the parameters for a blit where the backing store image currently contains oldLoc in the upper left hand corner and we're scrolling to newLoc. The blit* parameters are returned.

 public Dimension getExtentSize()

Returns the size of the visible part of the view in view coordinates.

 public Dimension toViewCoordinates(Dimension size)

Convert a size in pixel coordinates to view coordinates. Subclasses of viewport that support "logical coordinates" will override this method.

 public Point toViewCoordinates(Point p)

Convert a point in pixel coordinates to view coordinates. Subclasses of viewport that support "logical coordinates" will override this method.

 public void setExtentSize(Dimension newExtent)

Set the size of the visible part of the view, newExtent is in view coordinates.

 protected JViewport. ViewListener createViewListener()

 public void addChangeListener(ChangeListener x)

ChangeListeners are notified whenever the views position or extent size changes.

 public void removeChangeListener(ChangeListener x)

 protected LayoutManager createLayoutManager()

Subclassers can override this to install a different layout manager (or null) in the constructor. Returns a new JViewportLayout object.

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