diva.canvas

Class CanvasLayer

java.lang.Object

diva.canvas.CanvasLayer

All Implemented Interfaces:

CanvasComponent

Direct Known Subclasses:

EventLayer, FigureLayer, GridLayer, OverlayLayer

public abstract class CanvasLayer
extends java.lang.Object
implements CanvasComponent

A canvas layer is a single layer that lives within a CanvasPane. This is an abstract class -- concrete subclasses provide facilities for drawing graphics or handling events.

Version:

$Id$

Author:

John Reekie

Pt.AcceptedRating:

Yellow

Field Summary

Fields

Modifier and Type	Field and Description
(package private) CanvasPane	_containingPane The pane containing this layer.

Constructor Summary

Constructors

Constructor and Description
CanvasLayer() Create a new layer that is not in a pane.
CanvasLayer(CanvasPane pane) Create a new layer within the given pane.

Method Summary

Modifier and Type	Method and Description
CanvasPane	getCanvasPane() Get the pane containing this layer.
java.awt.geom.Rectangle2D	getLayerBounds() Get the bounds of the shapes draw in this layer.
CanvasComponent	getParent() Get the parent component, or null if there isn't one.
java.lang.String	getToolTipText(LayerEvent e) Get the toolTipText for the point in the given MouseEvent.
TransformContext	getTransformContext() Return the transform context of the parent pane, if there is one.
void	repaint() Schedule a repaint of this layer.
void	repaint(DamageRegion d) Accept notification that a repaint has occurred somewhere in this layer.
void	setParent(CanvasComponent parent) Set the parent component of this layer.

Methods inherited from class java.lang.Object

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

Field Detail

_containingPane

CanvasPane _containingPane

The pane containing this layer.

Constructor Detail

CanvasLayer

public CanvasLayer()

Create a new layer that is not in a pane. The layer will not be displayed, and its coordinate transformation will be as though it were a one-to-one mapping. Use of this constructor is strongly discouraged, as many of the geometry-related methods expect to see a pane.

CanvasLayer

public CanvasLayer(CanvasPane pane)

Create a new layer within the given pane.

Parameters:

pane - The pane in which to create the layer

Method Detail

getCanvasPane

public final CanvasPane getCanvasPane()

Get the pane containing this layer. This may be null.

Returns:

The pane containing the layter

getLayerBounds

public java.awt.geom.Rectangle2D getLayerBounds()

Get the bounds of the shapes draw in this layer. In this base class, return an empty rectangle.

Returns:

The bounds of this layer.

getParent

public final CanvasComponent getParent()

Get the parent component, or null if there isn't one. This will return the same object as getCanvasPane().

Specified by:

getParent in interface CanvasComponent

Returns:

The parent of this component.

getToolTipText

public java.lang.String getToolTipText(LayerEvent e)

Get the toolTipText for the point in the given MouseEvent. This works pretty much as regular event propagation in processLayerEvent.

Parameters:

e - The layer event, ignored in this class.

Returns:

This method always returns null.

getTransformContext

public final TransformContext getTransformContext()

Return the transform context of the parent pane, if there is one.

Specified by:

getTransformContext in interface CanvasComponent

Returns:

The transform context of this component.

repaint

public void repaint()

Schedule a repaint of this layer. The layer passes the repaint request to its containing pane, if there is one. Otherwise it does nothing.

Specified by:

repaint in interface CanvasComponent

repaint

public void repaint(DamageRegion d)

Accept notification that a repaint has occurred somewhere in this layer. Pass the notification up to the parent pane.

Specified by:

repaint in interface CanvasComponent

Parameters:

d - The region where a repaint has occurred.

setParent

public final void setParent(CanvasComponent parent)

Set the parent component of this layer. This must be an instance of CanvasPane.

Parameters:

parent - The parent of this layer