ComponentPeer

Name

Description

ComponentPeer is an interface that defines the basis for all non-menu GUI peer interfaces.

Interface Definition

public abstract interface java.awt.peer.ComponentPeer {
 // Interface Methods public abstract int checkImage (Image image, int width, int height, ImageObserver observer);
public abstract Image createImage (ImageProducer producer);
public abstract Image createImage (int width, int height);
public abstract void disable();  public abstract void dispose();
public abstract void enable();  public abstract ColorModel getColorModel();
public abstract FontMetrics getFontMetrics (Font f);
public abstract Graphics getGraphics();
public abstract Point getLocationOnScreen(); public abstract Dimension getMinimumSize(); public abstract Dimension getPreferredSize(); public abstract Toolkit getToolkit();
public abstract boolean handleEvent (Event e);
public abstract void hide();  public abstract boolean isFocusTraversable(); public abstract Dimension minimumSize();  public abstract void paint (Graphics g);
public abstract Dimension preferredSize ();  public abstract boolean prepareImage (Image image, int width, int height, ImageObserver observer);
public abstract void print (Graphics g);
public abstract void repaint (long tm, int x, int y, int width, int height);
public abstract void requestFocus();
public abstract void reshape (int x, int y, int width, int height);  public abstract void setBackground (Color c);
public abstract void setBounds (int x, int y, int width, int height); public abstract void setCursor (Cursor cursor); public abstract void setEnabled (boolean b); public abstract void setFont (Font f);
public abstract void setForeground (Color c);
public abstract void setVisible (boolean b); public abstract void show(); 
}

Interface Methods

checkImage

public abstract int checkImage (Image image, int width, int height, ImageObserver observer)

• Parameters
• • image
  • Image to check.
  • width
  • Horizontal size to which the image will be scaled.
  • height
  • Vertical size to which the image will be scaled.
  • observer
  • An ImageObserver to monitor image loading; normally, the object on which the image will be rendered.
• Returns
• ImageObserver flags ORed together indicating status.
• Description
• Checks status of image construction.

createImage

public abstract Image createImage (ImageProducer producer)

• Parameters
• • producer
  • An object that implements the ImageProducer interface to create a new image.
• Returns
• Newly created image instance.
• Description
• Creates an Image based upon an ImageProducer.

public abstract Image createImage (int width, int height)

• Parameters
• • width
  • Horizontal size for in-memory Image.
  • height
  • Vertical size for in-memory Image.
• Returns
• Newly created image instance.
• Description
• Creates an in-memory Image for double buffering.

disable

public abstract void disable()

• Description
• Disables component so that it is unresponsive to user interactions. Replaced by setEnabled(false).

dispose

public abstract void dispose()

• Description
• Releases resources used by peer.

enable

public abstract void enable()

• Description
• Enables component so that it is responsive to user interactions. Replaced by setEnabled(true).

getColorModel

public abstract ColorModel getColorModel()

• Returns
• ColorModel used to display the current component.

getFontMetrics

public abstract FontMetrics getFontMetrics (Font f)

• Parameters
• • f
  • A font whose metrics are desired.
• Returns
• Font sizing information for the desired font.

getGraphics

public abstract Graphics getGraphics()

• Throws
• • InternalException
  • If acquiring a graphics context is unsupported
• Returns
• Component's graphics context.

getLocationOnScreen

public abstract Point getLocationOnScreen()

• Returns
• The location of the component in the screen's coordinate space.

getMinimumSize

public abstract Dimension getMinimumSize()

• Returns
• The minimum dimensions of the component.

getPreferredSize

public abstract Dimension getPreferredSize()

• Returns
• The preferred dimensions of the component.

getToolkit

public abstract Toolkit getToolkit()

• Returns
• Toolkit of Component.

handleEvent

public abstract boolean handleEvent (Event e)

• Parameters
• • e
  • Event instance identifying what caused the method to be called.
• Returns
• true if the peer handled the event, false to propagate the event to the parent container.
• Description
• High-level event handling routine.

hide

public abstract void hide()

• Description
• Hides the component. Replaced by setVisible(false).

isFocusTraversable

public abstract boolean isFocusTraversable()

• Returns
• true if the peer can be tabbed onto, false otherwise.
• Description
• Determines if this peer is navigable using the keyboard.

minimumSize

public abstract Dimension minimumSize()

• Returns
• The minimum dimensions of the component. Replaced by getMinimumSize().

paint

public abstract void paint (Graphics g)

• Parameters
• • g
  • Graphics context of the component.
• Description
• Draws something in graphics context.

preferredSize

public abstract Dimension preferredSize()

• Returns
• The preferred dimensions of the component. Replaced by getPreferredSize().

prepareImage

public abstract boolean prepareImage (Image image, int width, int height, ImageObserver observer)

• Parameters
• • image
  • Image to load.
  • width
  • Horizontal size to which the image will be scaled.
  • height
  • Vertical size to which the image will be scaled.
  • observer
  • An ImageObserver to monitor image loading; normally, the object on which the image will be rendered.
• Returns
• true if the image has already loaded, false otherwise.
• Description
• Forces the image to start loading.

print

public abstract void print (Graphics g)

• Parameters
• • g
  • Graphics context of component.
• Description
• Print something from the graphics context.

repaint

public abstract void repaint (long tm, int x, int y, int width, int height)

• Parameters
• • tm
  • Millisecond delay allowed before repaint.
  • x
  • Horizontal origin of bounding box to redraw.
  • y
  • Vertical origin of bounding box to redraw.
  • width
  • Width of bounding box to redraw.
  • height
  • Height of bounding box to redraw.
• Description
• Requests scheduler to redraw portion of component within a time period.

requestFocus

public abstract void requestFocus()

• Description
• Requests this Component gets the input focus.

reshape

public abstract void reshape (int x, int y, int width, int height)

• Parameters
• • x
  • New horizontal position for component.
  • y
  • New vertical position for component.
  • width
  • New width for component.
  • height
  • New height for component.
• Description
• Relocates and resizes the component's peer. Replaced by setBounds(int, int, int, int).

setBackground

public abstract void setBackground (Color c)

• Parameters
• • c
  • New color for the background.
• Description
• Changes the background color of the component.

setBounds

public abstract void setBounds (int x, int y, int width, int height)

• Parameters
• • x
  • New horizontal position for component.
  • y
  • New vertical position for component.
  • width
  • New width for component.
  • height
  • New height for component.
• Description
• Relocates and resizes the component's peer.

setCursor

public abstract void setCursor (Cursor cursor)

• Parameters
• • cursor
  • New cursor.
• Description
• Changes the cursor of the component.

setEnabled

public abstract void setEnabled (boolean b)

• Parameters
• • b
  • true to enable the peer; false to disable it.
• Description
• Enables or disables the peer.

setFont

public abstract void setFont (Font f)

• Parameters
• • f
  • New font for the component.
• Description
• Changes the font used to display text in the component.

setForeground

public abstract void setForeground (Color c)

• Parameters
• • c
  • New foreground color for the component.
• Description
• Changes the foreground color of the component.

setVisible

public abstract void setVisible (boolean b)

• Parameters
• • b
  • true to show the peer; false to hide it.
• Description
• Shows or hides the peer.

show

public abstract void show()

• Description
• Makes the peer visible. Replaced by setVisible(true).

See Also

ButtonPeer, CanvasPeer, CheckboxPeer, ChoicePeer, Color, ColorModel, ContainerPeer, Cursor, Dimension, Event, Font, FontMetrics, Graphics, Image, ImageObserver, ImageProducer, LabelPeer, ListPeer, ScrollbarPeer, TextComponentPeer, Toolkit