diva.canvas

Class JCanvas

java.lang.Object

java.awt.Component

java.awt.Container

javax.swing.JComponent

diva.canvas.JCanvas

All Implemented Interfaces:

ImageObserver, MenuContainer, Printable, Serializable

Direct Known Subclasses:

JCanvasPalette, JGraph, JSketch, TestDrawActions

public class JCanvas
extends JComponent
implements Printable

The JCanvas class is the center-piece of this package. The canvas is composed of a canvas pane, which in turn is composed of one or more layers. Each layer may contain arbitrary graphics, although commonly at least one layer is an instance of a "figure layer" class that contains figure objects. The main role of the JCanvas class is to provide the physical screen space on which layers draw themselves, and to interface to the Swing component hierarchy.

This architecture allows a graphics developer to write code for a pane and a set of layers, without being concerned about whether the pane and its layers will be directly contained by a JCanvas or within some other layer. For example, it will be possible for a visualization component to be "embedded" in a larger component.

Version:

$Revision: 1.49 $

Author:

John Reekie

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces inherited from class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces inherited from class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

Fields inherited from class javax.swing.JComponent

listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Fields inherited from class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.print.Printable

NO_SUCH_PAGE, PAGE_EXISTS

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

Constructors

Constructor and Description
JCanvas() Create a new canvas that contains a single GraphicsPane.
JCanvas(CanvasPane pane) Create a new canvas that contains the given CanvasPane.

Method Summary

Modifier and Type	Method and Description
CanvasPane	getCanvasPane() Get the canvas pane contained by this component.
String	getToolTipText(MouseEvent e) Get the toolTipText for the point in the given MouseEvent.
boolean	isFocusTraversable() Return whether or not focus should be traversable across this object.
void	paintComponent(Graphics g) Paint the canvas.
int	print(Graphics graphics, PageFormat format, int index) Print the canvas to a printer, represented by the specified graphics object.
int	print(Graphics graphics, PageFormat format, int index, Rectangle2D printRegion) Print the canvas to a printer, represented by the specified graphics object.
protected void	processMouseEvent(MouseEvent e) Process a mouse event.
protected void	processMouseMotionEvent(MouseEvent e) Process a mouse motion event.
void	repaint(DamageRegion d) Accept notification that a repaint has occurred on in this canvas.
void	setCanvasPane(CanvasPane pane) Set the canvas pane contained by this JCanvas.
void	setDoubleBuffered(boolean flag) Turn double-buffering on this canvas on or off.
void	setPreferredSize(Dimension d) Set the preferred size of this JCanvas.

Methods inherited from class javax.swing.JComponent

addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getTopLevelAncestor, getTransferHandler, getUIClassID, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintImmediately, paintImmediately, paramString, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update, updateUI

Methods inherited from class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTree

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAccessibleContext, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle

Methods inherited from class java.lang.Object

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

Constructor Detail

JCanvas

public JCanvas()

Create a new canvas that contains a single GraphicsPane. This is the simplest way of using the JCanvas. Mouse events on the canvas are enabled by default.

JCanvas

public JCanvas(CanvasPane pane)

Create a new canvas that contains the given CanvasPane. Mouse events on the canvas are enabled by default.

Method Detail

getCanvasPane

public final CanvasPane getCanvasPane()

Get the canvas pane contained by this component.

getToolTipText

public String getToolTipText(MouseEvent e)

Get the toolTipText for the point in the given MouseEvent. Ask the canvasPane for a toolTip for the location of the mouse event. Note that you should not in general call setToolTipText on this canvas, since the value is ignored and the value returned by this method used instead. Even worse, if you call setToolTipText(null), then tooltips will probably get disabled entirely!

Overrides:

getToolTipText in class JComponent

isFocusTraversable

public boolean isFocusTraversable()

Return whether or not focus should be traversable across this object. This must return true to allow keyboard events to be grabbed. Return true in this class.

Overrides:

isFocusTraversable in class Component

paintComponent

public void paintComponent(Graphics g)

Paint the canvas. Every layer in this canvas will be requested to paint itself.

This method allocates an offscreen buffer if necessary, and then paints the canvas into the right buffer and blits it to the on-screen buffer.

Acknowledgement: some of this code was adapted from code posted by Jonathon Knudsen to the Java2D mailing list, May 1998.

Overrides:

paintComponent in class JComponent

print

public int print(Graphics graphics,
                 PageFormat format,
                 int index)
          throws PrinterException

Print the canvas to a printer, represented by the specified graphics object. Scale the size of the canvas to fit onto the printed page, while preserving the shape of the objects on the page.

Specified by:

print in interface Printable

Parameters:

graphics - The context into which the page is drawn.

format - The size and orientation of the page being drawn.

index - The zero based index of the page to be drawn.

Returns:

PAGE_EXISTS if the page is rendered successfully, or NO_SUCH_PAGE if pageIndex specifies a non-existent page.

Throws:

PrinterException - If the print job is terminated.

print

public int print(Graphics graphics,
                 PageFormat format,
                 int index,
                 Rectangle2D printRegion)
          throws PrinterException

Print the canvas to a printer, represented by the specified graphics object. Scale the given printRegion to fit onto the printed page, while preserving the shape of the objects on the page.

Parameters:

graphics - The context into which the page is drawn.

format - The size and orientation of the page being drawn.

index - The zero based index of the page to be drawn.

printRegion - The rectangular region of the canvaws, in screen coordinates, that will be printed to the screen.

Returns:

PAGE_EXISTS if the page is rendered successfully, or NO_SUCH_PAGE if pageIndex specifies a non-existent page.

Throws:

PrinterException - If the print job is terminated.

repaint

public void repaint(DamageRegion d)

Accept notification that a repaint has occurred on in this canvas. Call the given damage region to generate the appopriate calls to the Swing repaint manager.

setCanvasPane

public final void setCanvasPane(CanvasPane pane)

Set the canvas pane contained by this JCanvas. If there is already a pane in this JCanvas, replace it. If the pane already is in a canvas, remove it from that other canvas.

setDoubleBuffered

public void setDoubleBuffered(boolean flag)

Turn double-buffering on this canvas on or off. This method overrides the inherited method to delete the off-screen buffer.

Overrides:

setDoubleBuffered in class JComponent

setPreferredSize

public void setPreferredSize(Dimension d)

Set the preferred size of this JCanvas. In addition to calling the superclass method, this calls setSize() on the contained pane.

Overrides:

setPreferredSize in class JComponent

processMouseEvent

protected void processMouseEvent(MouseEvent e)

Process a mouse event. This method overrides the inherited method to create a LayerEvent or LayerMotionEvent and pass the event on to its pane (if it is not null). The mouse event is passed to the superclass' method for handling.

Overrides:

processMouseEvent in class JComponent

processMouseMotionEvent

protected void processMouseMotionEvent(MouseEvent e)

Process a mouse motion event. This method overrides the inherited method to create a LayerEvent or LayerMotionEvent and pass the event on to its pane (if it is not null). The mouse event is passed to the superclass' method for handling.

Overrides:

processMouseMotionEvent in class JComponent