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Chapter 23 java.awt.peer Reference |
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ComponentPeer
Name
ComponentPeer
![[Graphic: Figure from the text]](./figs/compon4.gif)
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.
- image
- 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.
- producer
- 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.
- width
- 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.
- f
- Returns
-
Font sizing information for the desired font.
getGraphics
public abstract Graphics getGraphics()
- Throws
-
- InternalException
-
If acquiring a graphics context is unsupported
- InternalException
- 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.
- e
- 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.
- g
- 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.
- image
- Returns
-
true if the image has already loaded, false otherwise.
- Description
-
Forces the image to start loading.
public abstract void print (Graphics g)
- Parameters
-
- g
-
Graphics context of component.
- g
- 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.
- tm
- 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.
- x
- 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.
- c
- 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.
- x
- Description
-
Relocates and resizes the component's peer.
setCursor
public abstract void setCursor (Cursor cursor)
- Parameters
-
- cursor
-
New cursor.
- 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.
- b
- Description
-
Enables or disables the peer.
setFont
public abstract void setFont (Font f)
- Parameters
-
- f
-
New font for the component.
- f
- 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.
- c
- 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.
- b
- 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
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| ChoicePeer |  |
ContainerPeer |
