edu.umd.cs.jazz.util
Class ZDefaultScrollDirector

java.lang.Object
  |
  +--edu.umd.cs.jazz.util.ZDefaultScrollDirector

All Implemented Interfaces:

java.util.EventListener, ZCameraListener, ZNodeListener, ZScrollDirector

public class ZDefaultScrollDirector

extends java.lang.Object

implements ZScrollDirector, ZCameraListener, ZNodeListener

The default implementation of the scroll director that 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

viewPort

protected ZViewport viewPort

The viewport that signals this scroll director

scrollPane

protected ZScrollPane scrollPane

The scrollpane that contains the viewport

view

protected ZCanvas view

The canvas that this class directs

camera

protected ZCamera camera

The canvas' camera

root

protected ZRoot root

The canvas' root

scrollInProgress

protected boolean scrollInProgress

Flag to indicate when scrolling is currently in progress

ZDefaultScrollDirector

public ZDefaultScrollDirector()

The default constructor

install

public void install(ZViewport viewPort,
                    ZCanvas view)

Installs the scroll director and adds the appropriate listeners

Specified by:

install in interface ZScrollDirector

Parameters:

viewPort - The viewport on which this director directs

view - The ZCanvas that the viewport looks at

unInstall

public void unInstall()

Uninstall the scroll director from the viewport

Specified by:

unInstall in interface ZScrollDirector

getViewPosition

public java.awt.Point getViewPosition(java.awt.geom.Rectangle2D viewBounds)

Get the View position given the specified camera bounds

Specified by:

getViewPosition in interface ZScrollDirector

Parameters:

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

Returns:

The view position

getViewSize

public java.awt.Dimension getViewSize(java.awt.geom.Rectangle2D viewBounds)

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

Specified by:

getViewSize in interface ZScrollDirector

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 ZScrollDirector

Parameters:

x - The new x position

y - The new y position

viewChanged

public void viewChanged(ZCameraEvent e)

Invoked when the camera's view transform changes.

Specified by:

viewChanged in interface ZCameraListener

Parameters:

e - The view changed camera event

boundsChanged

public void boundsChanged(ZNodeEvent e)

Invoked when a node has its bounds changed.

Specified by:

boundsChanged in interface ZNodeListener

Parameters:

e - The bounds changed event

globalBoundsChanged

public void globalBoundsChanged(ZNodeEvent e)

Invoked when a node has its global bounds changed. These can be ignored since a global bounds change will have a corresponding bounds change on the root

Specified by:

globalBoundsChanged in interface ZNodeListener

Parameters:

e - The ignored global bounds event

shouldRevalidateScrollPane

public boolean shouldRevalidateScrollPane()

Should the ScrollPane be revalidated? - This occurs when either the scrollbars are showing and should be remove or are note showing and should be added

Returns:

Whether the scroll pane should be revalidated