java.awt
Class Canvas

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Canvas

public class Canvas

extends Component

A Canvas component represents a blank rectangular area of the screen onto which the application can draw or from which the application can trap input events from the user.

An application must subclass the Canvas class in order to get useful functionality such as creating a custom component. The paint method must be overridden in order to perform custom graphics on the canvas.

Since:

JDK1.0

See Also:

Serialized Form

Inner classes inherited from class java.awt.Component

Component.AWTTreeLock, Component.NativeInLightFixer

Field Summary

private static String	base
private GraphicsConfiguration	graphicsConfig
private static int	nameCounter
private static long	serialVersionUID

Fields inherited from class java.awt.Component

actionListenerK, adjustmentListenerK, appContext, assert, background, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, changeSupport, componentListener, componentListenerK, componentOrientation, componentSerializedDataVersion, containerListenerK, cursor, dropTarget, enabled, eventMask, focusListener, focusListenerK, font, foreground, hasFocus, height, incRate, inputMethodListener, inputMethodListenerK, isInc, isPacked, itemListenerK, keyListener, keyListenerK, LEFT_ALIGNMENT, locale, LOCK, minSize, mouseListener, mouseListenerK, mouseMotionListener, mouseMotionListenerK, name, nameExplicitlySet, newEventsOnly, ownedWindowK, parent, peer, peerFont, popups, prefSize, RIGHT_ALIGNMENT, serialVersionUID, textListenerK, TOP_ALIGNMENT, valid, visible, width, windowListenerK, x, y

Constructor Summary

Canvas()
Constructs a new Canvas.

Canvas(GraphicsConfiguration config)
Constructs a new Canvas given a GraphicsConfiguration object.

Method Summary

void	addNotify() Creates the peer of the canvas.
(package private) String	constructComponentName() Construct a name for this component.
void	paint(Graphics g) This method is called to repaint this canvas.
(package private) boolean	postsOldMouseEvents()

Methods inherited from class java.awt.Component

, action, add, addComponentListener, addFocusListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addPropertyChangeListener, addPropertyChangeListener, areInputMethodsEnabled, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, deliverEvent, disable, disableEvents, dispatchEvent, dispatchEventImpl, doLayout, enable, enable, enableEvents, enableInputMethods, eventEnabled, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentOrientation, getCursor, getDropTarget, getFont_NoClientCode, getFont, getFontMetrics, getForeground, getGraphics, getHeight, getInputContext, getInputMethodRequests, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getName, getNativeContainer, getParent_NoClientCode, getParent, getPeer, getPreferredSize, getSize, getSize, getToolkit, getToolkitImpl, getTreeLock, getWidth, getWindowForObject, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, initIDs, inside, invalidate, isDisplayable, isDoubleBuffered, isEnabled, isEnabledImpl, isFocusTraversable, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, layout, lightweightPrint, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, paramString, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, processFocusEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, readObject, remove, removeComponentListener, removeFocusListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFont, setForeground, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, show, size, toString, transferFocus, update, validate, writeObject

Methods inherited from class java.lang.Object

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

Field Detail

base

private static final String base

nameCounter

private static int nameCounter

graphicsConfig

private GraphicsConfiguration graphicsConfig

serialVersionUID

private static final long serialVersionUID

Constructor Detail

Canvas

public Canvas()

Constructs a new Canvas.

Canvas

public Canvas(GraphicsConfiguration config)

Constructs a new Canvas given a GraphicsConfiguration object.

Parameters:

config - a reference to a GraphicsConfiguration object.

See Also:

GraphicsConfiguration

Method Detail

constructComponentName

String constructComponentName()

Construct a name for this component. Called by getName() when the name is null.

Overrides:

constructComponentName in class Component

addNotify

public void addNotify()

Creates the peer of the canvas. This peer allows you to change the user interface of the canvas without changing its functionality.

Overrides:

addNotify in class Component

See Also:

Toolkit.createCanvas(java.awt.Canvas), Component.getToolkit()

paint

public void paint(Graphics g)

This method is called to repaint this canvas. Most applications that subclass Canvas should override this method in order to perform some useful operation.

The paint method provided by Canvas redraws this canvas's rectangle in the background color.

The graphics context's origin (0, 0) is the top-left corner of this canvas. Its clipping region is the area of the context.

Parameters:

g - the graphics context.

Overrides:

paint in class Component

See Also:

Graphics

postsOldMouseEvents

boolean postsOldMouseEvents()

Overrides:

postsOldMouseEvents in class Component