java.lang.Objectjava.awt.Component
java.awt.Canvas
public class Canvas
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.
Nested Class Summary | |
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protected class |
Canvas.AccessibleAWTCanvas
This class implements accessibility support for the Canvas class. |
Nested classes/interfaces inherited from class java.awt. Component |
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Component.AccessibleAWTComponent , Component.BaselineResizeBehavior , Component.BltBufferStrategy , Component.FlipBufferStrategy |
Field Summary |
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Fields inherited from class java.awt. Component |
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BOTTOM_ALIGNMENT , CENTER_ALIGNMENT , LEFT_ALIGNMENT , RIGHT_ALIGNMENT , TOP_ALIGNMENT |
Fields inherited from interface java.awt.image. ImageObserver |
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ABORT , ALLBITS , ERROR , FRAMEBITS , HEIGHT , PROPERTIES , SOMEBITS , WIDTH |
Constructor Summary | |
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Canvas
() Constructs a new Canvas. |
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Canvas
(
GraphicsConfiguration
config) Constructs a new Canvas given a GraphicsConfiguration object. |
Method Summary | |
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void |
addNotify
() Creates the peer of the canvas. |
void |
createBufferStrategy
(int numBuffers) Creates a new strategy for multi-buffering on this component. |
void |
createBufferStrategy
(int numBuffers,
BufferCapabilities
caps) Creates a new strategy for multi-buffering on this component with the required buffer capabilities. |
AccessibleContext |
getAccessibleContext
() Gets the AccessibleContext associated with this Canvas. |
BufferStrategy |
getBufferStrategy
() Returns the BufferStrategy used by this component. |
void |
paint
(
Graphics
g) Paints this canvas. |
void |
update
(
Graphics
g) Updates this canvas. |
Methods inherited from class java.lang. Object |
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clone , equals , finalize , getClass , hashCode , notify , notifyAll , wait , wait , wait |
Constructor Detail |
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public Canvas()
public Canvas(GraphicsConfiguration config)
Method Detail |
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public void addNotify()
public void paint(Graphics g)
Most applications that subclass Canvas should override this method in order to perform some useful operation (typically, custom painting of the canvas). The default operation is simply to clear the canvas. Applications that override this method need not call super.paint(g).
public void update(Graphics g)
This method is called in response to a call to repaint. The canvas is first cleared by filling it with the background color, and then completely redrawn by calling this canvas's paint method. Note: applications that override this method should either call super.update(g) or incorporate the functionality described above into their own code.
public void createBufferStrategy(int numBuffers)
Each time this method is called, the existing buffer strategy for this component is discarded.
public void createBufferStrategy(int numBuffers, BufferCapabilities caps) throws AWTException
Each time this method is called, the existing buffer strategy for this component is discarded.
public BufferStrategy getBufferStrategy()
public AccessibleContext getAccessibleContext()