CanvasPane

java.lang.Object
- diva.canvas.CanvasPane

All Implemented Interfaces:

CanvasComponent, EventAcceptor

Direct Known Subclasses:

BasicCanvasPane, GraphicsPane
```
public abstract class CanvasPane
extends java.lang.Object
implements EventAcceptor, CanvasComponent
```
A canvas pane groups canvas layers. The layers all share the same logical-to-screen transform as the canvas pane. This is an abstract superclass of all canvas panes, and provides the implementation of everything related to panes but the storage of the layers. Subclasses must provide methods to add and (possibly) reorder and remove layers. Particular applications may choose to create their own special-purpose sub-classes.

Version:

$Id: CanvasPane.java 70398 2014-10-22 23:44:32Z cxh $

Author:

John Reekie

Accepted Rating:
Yellow

Constructor Summary

Constructors
Constructor and Description

CanvasPane()

Constructors
Constructor and Description
`CanvasPane()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`_initNewLayer(CanvasLayer l)` Helper method to initialize a layer when it is added to this pane.
`protected void`	`_nullifyLayer(CanvasLayer l)` Helper method to tell a layer when it is been removed from this pane.
`void`	`dispatchEvent(java.awt.AWTEvent event)` Dispatch an AWT event on this pane.
`JCanvas`	`getCanvas()` Get the containing canvas, or null if there isn't one.
`CanvasComponent`	`getParent()` Get the parent component, or null if there isn't one.
`java.awt.geom.Point2D`	`getSize()` Get the size of this pane, in logical coordinates.
`protected java.lang.String`	`getToolTipText(LayerEvent event)` Get the toolTipText for the point in the given LayerEvent.
`TransformContext`	`getTransformContext()` Return the transform context of this pane.
`boolean`	`isAntialiasing()` Return whether or not this pane is antialiased
`boolean`	`isEnabled()` Test the enabled flag of this pane.
`java.util.Iterator`	`layers()` Return an iteration of the layers, in undefined order.
`abstract java.util.Iterator`	`layersFromBack()` Return an iteration of the layers from back to front -- that is, in redraw order.
`abstract java.util.Iterator`	`layersFromFront()` Return an iteration of the layers from front to back -- that is, in event-processing order.
`void`	`paint(java.awt.Graphics2D g)` Paint this pane onto a 2D graphics context.
`void`	`paint(java.awt.Graphics2D g, java.awt.geom.Rectangle2D region)` Paint this pane onto a 2D graphics object, within the given region.
`protected void`	`processLayerEvent(LayerEvent event)` Process a layer event that has occurred on this pane.
`void`	`repaint()` Schedule a repaint of this pane.
`void`	`repaint(DamageRegion d)` Accept notification that a repaint has occurred somewhere in this pane.
`void`	`scale(double xcenter, double ycenter, double xscale, double yscale)` Scale this pane the given amount.
`void`	`setAntialiasing(boolean val)` Set whether or not to use antialiasing when drawing this pane.
`void`	`setCanvas(JCanvas canvas)` Set the containing canvas of this pane.
`void`	`setEnabled(boolean flag)` Set the enabled flag of this pane.
`void`	`setParent(CanvasComponent parent)` Set the parent component of this pane.
`void`	`setSize(double width, double height)` Set the size of this pane, in logical coordinates.
`void`	`setSize(java.awt.geom.Point2D size)` Set the size of this pane, in logical coordinates.
`void`	`setTransform(java.awt.geom.AffineTransform at)` Set the transform that maps logical coordinates into the parent's coordinates.
`void`	`translate(double x, double y)` Translate this pane the given distance.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CanvasPane
```
public CanvasPane()
```
- Method Detail
  - dispatchEvent
```
public void dispatchEvent(java.awt.AWTEvent event)
```
    Dispatch an AWT event on this pane. Currently only layer events are handled.
    
    Specified by:
    
    dispatchEvent in interface EventAcceptor
  - getParent
```
public final CanvasComponent getParent()
```
    Get the parent component, or null if there isn't one. Only one of the canvas or the display parent can be non-null.
    
    Specified by:
    
    getParent in interface CanvasComponent
    
    Returns:
    
    The parent of this component.
  - getCanvas
```
public final JCanvas getCanvas()
```
    Get the containing canvas, or null if there isn't one. Only one of the canvas or the display parent can be non-null.
  - isAntialiasing
```
public final boolean isAntialiasing()
```
    Return whether or not this pane is antialiased
  - getToolTipText
```
protected java.lang.String getToolTipText(LayerEvent event)
```
    Get the toolTipText for the point in the given LayerEvent. Pass the event to all the layers in this canvas pane in order from front to back. The returned value will be the first non-null tooltip string returned by one of the layers. If all the layers return a null tooltip, then return null indicating that no tooltip should be displayed.
  - getTransformContext
```
public final TransformContext getTransformContext()
```
    Return the transform context of this pane.
    
    Specified by:
    
    getTransformContext in interface CanvasComponent
    
    Returns:
    
    The transform context of this component.
  - getSize
```
public java.awt.geom.Point2D getSize()
```
    Get the size of this pane, in logical coordinates. If the pane is contained directly in a JCanvas, the size is obtained from the JCanvas. Otherwise, it returns the size previously set with setSize().
  - isEnabled
```
public final boolean isEnabled()
```
    Test the enabled flag of this pane. Note that this flag does not indicate whether the pane is actually enabled, as its canvas or one if its ancestors may not be enabled.
    
    Specified by:
    
    isEnabled in interface EventAcceptor
  - layers
```
public java.util.Iterator layers()
```
    Return an iteration of the layers, in undefined order. The default implementation simply calls layersFromFront().
  - layersFromBack
```
public abstract java.util.Iterator layersFromBack()
```
    Return an iteration of the layers from back to front -- that is, in redraw order.
  - layersFromFront
```
public abstract java.util.Iterator layersFromFront()
```
    Return an iteration of the layers from front to back -- that is, in event-processing order.
  - paint
```
public void paint(java.awt.Graphics2D g)
```
    Paint this pane onto a 2D graphics context. This implementation paints all layers that implement VisibleComponent, from back to front. The transform of this pane is written into the graphics context, so any layer that changes the transform is obliged to return it to its prior state after finishing.
  - paint
```
public void paint(java.awt.Graphics2D g,
                  java.awt.geom.Rectangle2D region)
```
    Paint this pane onto a 2D graphics object, within the given region. This implementation paints all layers that implement VisibleComponent, from highest index to lowest index. The transform of this pane is written into the graphics context, so any layer that changes the transform is obliged to return it to its prior state after finishing.
  - processLayerEvent
```
protected void processLayerEvent(LayerEvent event)
```
    Process a layer event that has occurred on this pane. If the pane is not enabled, return without doing anything. Otherwise, pass the event to each layer that implements the EventAcceptor interface, from front to back. After each layer, check whether the event has been consumed, and return if so.
  - repaint
```
public void repaint()
```
    Schedule a repaint of this pane. The pane passes the repaint request to its parent, if it has one.
    
    Specified by:
    
    repaint in interface CanvasComponent
  - repaint
```
public void repaint(DamageRegion d)
```
    Accept notification that a repaint has occurred somewhere in this pane. Notify the damage region that it is passing through a transform context, and then forward the notification up to the parent.
    
    Specified by:
    
    repaint in interface CanvasComponent
    
    Parameters:
    
    d - The region where a repaint has occurred.
  - setAntialiasing
```
public void setAntialiasing(boolean val)
```
    Set whether or not to use antialiasing when drawing this pane.
  - setCanvas
```
public final void setCanvas(JCanvas canvas)
```
    Set the containing canvas of this pane. If the canvas is not null and the parent is not null, throw an exception. This method is not intended for general use, only by JCanvas and subclasses.
  - setEnabled
```
public final void setEnabled(boolean flag)
```
    Set the enabled flag of this pane. If the flag is false, then the pane will not respond to user input events.
    
    Specified by:
    
    setEnabled in interface EventAcceptor
  - setParent
```
public final void setParent(CanvasComponent parent)
```
    Set the parent component of this pane. If the parent is not null and the canvas is not null, throw an exception.
  - setSize
```
public void setSize(double width,
                    double height)
```
    Set the size of this pane, in logical coordinates. If the pane is directly contained by a JCanvas, subsequent calls to the getSize() and getPreferredSize() methods of the JCanvas will return the size set here.
  - setSize
```
public void setSize(java.awt.geom.Point2D size)
```
    Set the size of this pane, in logical coordinates. If the pane is directly contained by a JCanvas, subsequent calls to the getSize() and getPreferredSize() methods of the JCanvas will return the size set here.
  - setTransform
```
public final void setTransform(java.awt.geom.AffineTransform at)
```
    Set the transform that maps logical coordinates into the parent's coordinates. If there is no parent, the "parent" is taken to be the screen. An exception will be thrown if the transform is null. Note that the transform will be remembered by this pane, so any further changes to the transform will affect the pane. This version has a flag that can be used to avoid calling the 'updateRangeModel' method
  - translate
```
public void translate(double x,
                      double y)
```
    Translate this pane the given distance. The translation is done such that it works "correctly" in the presence of scaling.
  - scale
```
public void scale(double xcenter,
                  double ycenter,
                  double xscale,
                  double yscale)
```
    Scale this pane the given amount. The first two arguments are the center point to scale about, the second two are the horizontal and vertical scale factors.
  - _initNewLayer
```
protected void _initNewLayer(CanvasLayer l)
```
    Helper method to initialize a layer when it is added to this pane. Any subclass must be sure to call this whenever it creates a new layer or accepts one to add to itself.
  - _nullifyLayer
```
protected void _nullifyLayer(CanvasLayer l)
```
    Helper method to tell a layer when it is been removed from this pane. Any subclass must be sure to call this whenever it removes a layer.

Class CanvasPane

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

CanvasPane

Method Detail

dispatchEvent

getParent

getCanvas

isAntialiasing

getToolTipText

getTransformContext

getSize

isEnabled

layers

layersFromBack

layersFromFront

paint

paint

processLayerEvent

repaint

repaint

setAntialiasing

setCanvas

setEnabled

setParent

setSize

setSize

setTransform

translate

scale

_initNewLayer

_nullifyLayer