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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

implements Accessible

backingStore

backingStoreImage

changeEvent

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)

Adds a ChangeListener to the button.

computeBlit(int, int, 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()

fireStateChanged()

getAccessibleRole()

Get the role of this object.

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.

getViewRect()

Return a rectangle whose origin is getViewPosition and size is getExtentSize().

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)

Depending on whether the backingStore is enabled, either paint the image through the backing store or paint just the recently exposed part, using the backing store to "blit" the remainder.

remove(Component)

removeChangeListener(ChangeListener)

Removes a ChangeListener from the button.

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)

Moves and resizes this component.

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 boolean scrollUnderway

 protected ComponentListener viewListener

 protected transient 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)

Depending on whether the backingStore is enabled, either paint the image through the backing store or paint just the recently exposed part, using the backing store to "blit" the remainder.

Overrides:

paint in class JComponent

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

Moves and resizes this component.

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 Rectangle getViewRect()

Return a rectangle whose origin is getViewPosition and size is getExtentSize(). This is the visible part of the view, in view coordinates.

Returns:

The visible part of the view, in view coordinates.

 protected boolean computeBlit(int dx,
                               int dy,
                               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 l)

Adds a ChangeListener to the button.

 public void removeChangeListener(ChangeListener l)

Removes a ChangeListener from the button.

 protected void fireStateChanged()

 protected LayoutManager createLayoutManager()

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

 public AccessibleRole getAccessibleRole()

Get the role of this object.

Returns:

an instance of AccessibleRole describing the role of the object

Overrides:

getAccessibleRole in class JComponent

See Also:

AccessibleRole

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