java.awt
public class Canvas extends Component implements Serializable, Accessible
Canvas
component provides a blank rectangular
area, which the client application can use for drawing and for
capturing events. By overriding the paint()
method,
the canvas can be used for anything from simple line drawings to
full-scale custom components.Modifier and Type | Class and Description |
---|---|
protected class |
Canvas.AccessibleAWTCanvas
This class provides accessibility support for the canvas.
|
Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
Constructor and Description |
---|
Canvas()
Initializes a new instance of
Canvas . |
Canvas(GraphicsConfiguration graphicsConfiguration)
Initializes a new instance of
Canvas
with the supplied graphics configuration. |
Modifier and Type | Method and Description |
---|---|
void |
addNotify()
Creates the native peer for this object.
|
void |
createBufferStrategy(int numBuffers)
Creates a buffering strategy that manages how this canvas is
repainted.
|
void |
createBufferStrategy(int numBuffers,
BufferCapabilities caps)
Creates a buffering strategy that manages how this canvas is
repainted.
|
AccessibleContext |
getAccessibleContext()
Gets the AccessibleContext associated with this
Canvas . |
BufferStrategy |
getBufferStrategy()
Returns the buffer strategy used by the canvas.
|
void |
paint(Graphics gfx)
Repaints the canvas window.
|
void |
update(Graphics graphics)
Updates the canvas in response to a request to
repaint() it. |
action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMinimumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, 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, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, validate
public Canvas()
Canvas
.public Canvas(GraphicsConfiguration graphicsConfiguration)
Canvas
with the supplied graphics configuration.graphicsConfiguration
- the graphics configuration to use
for this particular canvas.public void addNotify()
addNotify
in class Component
Component.isDisplayable()
,
Component.removeNotify()
public void paint(Graphics gfx)
paint
in class Component
gfx
- the Graphics
to use for paintingComponent.update(Graphics)
public AccessibleContext getAccessibleContext()
Canvas
.
The context is created, if necessary.getAccessibleContext
in interface Accessible
getAccessibleContext
in class Component
public void createBufferStrategy(int numBuffers)
numBuffers
- the number of buffers in this strategyIllegalArgumentException
- if requested number of buffers
is less than oneIllegalStateException
- if this canvas is not displayablepublic void createBufferStrategy(int numBuffers, BufferCapabilities caps) throws AWTException
numBuffers
- the number of buffers in this strategycaps
- the requested buffering capabilitiesAWTException
- if the requested capabilities are not
supportedIllegalArgumentException
- if requested number of buffers
is less than one or if caps is nullpublic BufferStrategy getBufferStrategy()
public void update(Graphics graphics)
repaint()
it. The canvas is cleared
with the current background colour, before paint()
is called to add the new contents. Subclasses
which override this method should either call this
method via super.update(graphics)
or re-implement
this behaviour, so as to ensure that the canvas is
clear before painting takes place.update
in class Component
graphics
- the graphics context.Component.paint(Graphics)
,
Component.repaint()