edu.umd.cs.piccolox.swing
Class PDefaultScrollDirector

java.lang.Object
  edu.umd.cs.piccolox.swing.PDefaultScrollDirector

All Implemented Interfaces:

PScrollDirector, PropertyChangeListener, EventListener

public class PDefaultScrollDirector
extends Object
implements PScrollDirector, PropertyChangeListener

The default scroll director implementation. This default implementation follows the widely accepted model of scrolling - namely the scrollbars control the movement of the window over the document rather than the movement of the document under the window.

Author:

Lance Good

Field Summary

protected PCamera	camera The canvas' camera.
protected PRoot	root The canvas' root.
protected boolean	scrollInProgress Flag to indicate when scrolling is currently in progress.
protected PScrollPane	scrollPane The scrollpane that contains the viewport.
protected PCanvas	view The canvas that this class directs.
protected PViewport	viewPort The viewport that signals this scroll director.

Constructor Summary

PDefaultScrollDirector()
The default constructor.

Method Summary

Point	getViewPosition(Rectangle2D viewBounds) Get the View position given the specified camera bounds.
Dimension	getViewSize(Rectangle2D viewBounds) Get the size of the view based on the specified camera bounds.
void	install(PViewport targetViewPort, PCanvas targetView) Installs the scroll director and adds the appropriate listeners.
void	propertyChange(PropertyChangeEvent pce) Invoked when the camera's view changes, or the bounds of the root or camera changes.
void	setViewPosition(double x, double y) Set the view position in a manner consistent with standardized scrolling.
boolean	shouldRevalidateScrollPane() Should the ScrollPane be revalidated.
void	unInstall() Uninstall the scroll director from the viewport.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

viewPort

protected PViewport viewPort

The viewport that signals this scroll director.

scrollPane

protected PScrollPane scrollPane

The scrollpane that contains the viewport.

view

protected PCanvas view

The canvas that this class directs.

camera

protected PCamera camera

The canvas' camera.

root

protected PRoot root

The canvas' root.

scrollInProgress

protected boolean scrollInProgress

Flag to indicate when scrolling is currently in progress.

Constructor Detail

PDefaultScrollDirector

public PDefaultScrollDirector()

The default constructor.

Method Detail

install

public void install(PViewport targetViewPort,
                    PCanvas targetView)

Installs the scroll director and adds the appropriate listeners.

Specified by:

install in interface PScrollDirector

Parameters:

targetViewPort - viewport on which this director directs

targetView - PCanvas that the viewport looks at

unInstall

public void unInstall()

Uninstall the scroll director from the viewport.

Specified by:

unInstall in interface PScrollDirector

getViewPosition

public Point getViewPosition(Rectangle2D viewBounds)

Get the View position given the specified camera bounds.

Specified by:

getViewPosition in interface PScrollDirector

Parameters:

viewBounds - The bounds for which the view position will be computed

Returns:

The view position

getViewSize

public Dimension getViewSize(Rectangle2D viewBounds)

Get the size of the view based on the specified camera bounds.

Specified by:

getViewSize in interface PScrollDirector

Parameters:

viewBounds - The view bounds for which the view size will be computed

Returns:

The view size

setViewPosition

public void setViewPosition(double x,
                            double y)

Set the view position in a manner consistent with standardized scrolling.

Specified by:

setViewPosition in interface PScrollDirector

Parameters:

x - The new x position

y - The new y position

propertyChange

public void propertyChange(PropertyChangeEvent pce)

Invoked when the camera's view changes, or the bounds of the root or camera changes.

Specified by:

propertyChange in interface PropertyChangeListener

Parameters:

pce - property change event to examine

shouldRevalidateScrollPane

public boolean shouldRevalidateScrollPane()

Should the ScrollPane be revalidated. This occurs when either the scroll bars are showing and should be remove or are not showing and should be added.

Returns:

Whether the scroll pane should be revalidated