Class com.sun.java.swing.JViewport
java.lang.Object
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+----java.awt.Component
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+----java.awt.Container
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+----com.sun.java.swing.JComponent
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+----com.sun.java.swing.JViewport
- public class JViewport
- extends JComponent
- implements Accessible
The "view port" through which you see information as it scrolls
by underneath the "port hole". Kind of like moving a square
magnifying glass up and down a page. Moving the magnifying glass
up brings the contents above into view.
Warning: serialized objects of this class will not be compatible with
future swing releases. The current serialization support is appropriate
for short term storage or RMI between Swing1.0 applications. It will
not be possible to load serialized Swing1.0 objects with future releases
of Swing. The JDK1.2 release of Swing will be the compatibility
baseline for the serialized form of Swing objects.
Variable Index
- backingStore
-
- backingStoreImage
-
- isViewSizeSet
-
- lastPaintPosition
- The last viewPosition that we've painted, so we know how
much of the backing store image is valid.
- scrollUnderway
-
Constructor Index
- JViewport()
-
Method Index
- addChangeListener(ChangeListener)
- Add a ChangeListener to the list that's notified each time the views
size, position, or the viewports extent size has changed.
- addImpl(Component, Object, int)
- Sets the Viewports one lightweight child, child can be null.
- 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()
-
- getAccessibleContext()
- Get the AccessibleContext associated with this JComponent
- getExtentSize()
- Returns the size of the visible part of the view in view coordinates.
- getInsets()
-
- 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.
- isOptimizedDrawingEnabled()
- Returns true if this component tiles its children, i.e.
- 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)
- Remove a ChangeListener from the list that's notified each
time the views size, position, or the viewports extent size
has changed.
- repaint(long, int, int, int, int)
- We always repaint in our parent coordinate system to make sure
only one paint is performed by the RepaintManager
- 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.
- setBorder(Border)
- 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).
- 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,
view
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.
Variables
isViewSizeSet
protected boolean isViewSizeSet
lastPaintPosition
protected Point lastPaintPosition
- The last viewPosition that we've painted, so we know how
much of the backing store image is valid.
backingStore
protected boolean backingStore
backingStoreImage
protected transient Image backingStoreImage
scrollUnderway
protected boolean scrollUnderway
Constructors
JViewport
public JViewport()
Methods
addImpl
protected void addImpl(Component child,
Object constraints,
int index)
- Sets the Viewports one lightweight child, child can be null.
- Overrides:
- addImpl in class Container
- See Also:
- setView
remove
public void remove(Component child)
- Overrides:
- remove in class Container
scrollRectToVisible
public void scrollRectToVisible(Rectangle contentRect)
- Overridden to scroll the View such that aRect within the
View becomes visible.
- Overrides:
- scrollRectToVisible in class JComponent
setBorder
public final void setBorder(Border border)
- 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). A non-null border,
or non-zero insets, isn't supported, to prevent the geometry
of this component from becoming complex enough to inhibit
subclassing. To createa JViewport with a border, add it to a
JPanel that has a border.
- Overrides:
- setBorder in class JComponent
getInsets
public final Insets getInsets()
- Returns:
- new Insets(0, 0, 0, 0)
- Overrides:
- getInsets in class JComponent
- See Also:
- setBorder
isOptimizedDrawingEnabled
public boolean isOptimizedDrawingEnabled()
- Returns true if this component tiles its children, i.e.
- Overrides:
- isOptimizedDrawingEnabled in class JComponent
paint
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
setBounds
public void setBounds(int x,
int y,
int w,
int h)
- Overrides:
- setBounds in class Component
isBackingStoreEnabled
public boolean isBackingStoreEnabled()
- Returns true if this viewport is maintaining an offscreen
image of its contents.
setBackingStoreEnabled
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.
getView
public Component getView()
- Returns the Viewports one child or null.
- See Also:
- setView
setView
public void setView(Component view)
- Sets the Viewports one lightweight child,
view
can be null.
- See Also:
- getView
getViewSize
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.
setViewSize
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.
getViewPosition
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.
setViewPosition
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.
getViewRect
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.
computeBlit
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.
getExtentSize
public Dimension getExtentSize()
- Returns the size of the visible part of the view in view coordinates.
toViewCoordinates
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.
toViewCoordinates
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.
setExtentSize
public void setExtentSize(Dimension newExtent)
- Set the size of the visible part of the view, newExtent is
in view coordinates.
createViewListener
protected JViewport. ViewListener createViewListener()
createLayoutManager
protected LayoutManager createLayoutManager()
- Subclassers can override this to install a different
layout manager (or null) in the constructor. Returns
a new JViewportLayout object.
addChangeListener
public void addChangeListener(ChangeListener l)
- Add a ChangeListener to the list that's notified each time the views
size, position, or the viewports extent size has changed.
- See Also:
- removeChangeListener, setViewPosition, setViewSize, setExtentSize
removeChangeListener
public void removeChangeListener(ChangeListener l)
- Remove a ChangeListener from the list that's notified each
time the views size, position, or the viewports extent size
has changed.
- See Also:
- addChangeListener
fireStateChanged
protected void fireStateChanged()
repaint
public void repaint(long tm,
int x,
int y,
int w,
int h)
- We always repaint in our parent coordinate system to make sure
only one paint is performed by the RepaintManager
- Overrides:
- repaint in class JComponent
getAccessibleContext
public AccessibleContext getAccessibleContext()
- Get the AccessibleContext associated with this JComponent
- Returns:
- the AccessibleContext of this JComponent
- Overrides:
- getAccessibleContext in class JComponent
