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§3.6 Interface ComponentPeer
The component peer interface specifies the methods that all implementations of Abstract
Window Toolkit components must define.
public interface java.awt.peer.ComponentPeer
{
// Methods
public abstract int §3.6.1
checkImage(Image img, int w, int h, ImageObserver o);
public abstract Image §3.6.2
createImage(ImageProducer producer);
public abstract Image §3.6.3
createImage(int width, int height);
public abstract void disable(); §3.6.4
public abstract void dispose(); §3.6.5
public abstract void enable(); §3.6.6
public abstract ColorModel getColorModel(); §3.6.7
public abstract FontMetrics getFontMetrics(Font font); §3.6.8
public abstract Graphics getGraphics(); §3.6.9
public abstract Toolkit getToolkit(); §3.6.10
public abstract boolean handleEvent(Event e); §3.6.11
public abstract void hide(); §3.6.12
public abstract Dimension minimumSize(); §3.6.13
public abstract void nextFocus(); §3.6.14
public abstract void paint(Graphics g); §3.6.15
public abstract Dimension preferredSize(); §3.6.16
public abstract boolean §3.6.17
prepareImage(Image img, int w, int h, ImageObserver o);
public abstract void print(Graphics g); §3.6.18
public abstract void repaint(long tm, int x, int y, §3.6.19
int width, int height);
public abstract void requestFocus(); §3.6.21
public abstract void reshape(int x, int y, int width, §3.6.22
int height);
public abstract void setBackground(Color c); §3.6.23
public abstract void setFont(Font f); §3.6.24
public abstract void setForeground(Color c); §3.6.25
public abstract void show(); §3.6.26
}
checkImage
public abstract int
checkImage(Image img, int w, int h, ImageObserver o)
- Returns the status of the construction of a scaled screen representation of
the specified image.
- This method does not cause the image to begin loading. An application
must use the prepareImage (II-§3.6.17) method to force the loading of an
image.
- Information on the flags returned by this method can be found
in (II-§2.11).
- Parameters:
img
- the Image whose status is being checked
w
- the width of the scaled version to check the status of
h
- the height of the scaled version to check the status of
o
- the ImageObserver object to be notified as the image is being
prepared
- Returns:
- the bitwise inclusive OR of the ImageObserver (II-§2.11) flags for the
data that is currently available
- See Also:
- prepareImage (II-§3.6.17).
createImage
public abstract Image createImage(ImageProducer producer)
- Creates an image from the specified image producer.
- Parameters:
producer
- the image producer
- Returns:
- the image produced
createImage
public abstract Image createImage(int width, int height)
- Creates an off-screen drawable image to be used for double buffering.
- Parameters:
width
- the specified width
height
- the specified height
- Returns:
- an off-screen drawable image.
disable
public abstract void disable()
- Makes the component insensitive to user input.
- See Also:
- enable (II-§3.6.6).
dispose
public abstract void dispose()
- Disposes of the component peer and any resources used by it
enable
public abstract void enable()
- Makes the component sensitive to user input. This is the default.
- See Also:
- disable (II-§3.6.4).
getColorModel
public abstract ColorModel getColorModel()
- Gets the component's color model (II-§2.1), which is an abstract class that
encapsulates how to translate between pixel values of an image and its red,
green, blue, and alpha components.
- Returns:
- the color model of the component.
getFontMetrics
public abstract FontMetrics getFontMetrics(Font font)
- Parameters:
font
- the font
- Returns:
- the font metrics for this component; if the component is not currently
on the screen, this method returns null.
getGraphics
public abstract Graphics getGraphics()
- Returns:
- the graphics context of this component; this method returns null if the
component is not currently on the screen.
- See Also:
- paint (II-§3.6.15).
getToolkit
public abstract Toolkit getToolkit()
- Returns:
- the toolkit that component peer is part of.
handleEvent
public abstract boolean handleEvent(Event e)
- This method is called when any event occurs inside the component.
- The method must return true to indicate that it has successfully handled the
action; or false if the event that triggered the action should be passed up to
the component's containing object.
- Parameters:
e
- the event
- Returns:
- false if the event is to be given to the component's containing object;
true if the event has been handled and no further action is necessary.
hide
public abstract void hide()
- Hides the component.
- See Also:
- show (II-§3.6.26).
minimumSize
public abstract Dimension minimumSize()
- Returns:
- the minimum size of this component.
- See Also:
- preferredSize (II-§3.6.16).
nextFocus
public abstract void nextFocus()
- Moves the focus to the next component.
paint
public abstract void paint(Graphics g)
- Paints the component.
- The
coordinate of the graphics context is the top-left corner of the
components. The clipping region of the graphics context is the rectangle of
the component.
- Parameters:
g
- the graphics context to use for painting.
preferredSize
public abstract Dimension preferredSize()
- Returns:
- the preferred size of this component.
- See Also:
- minimumSize (II-§3.6.13).
prepareImage
public abstract boolean
prepareImage(Image img, int w, int h, ImageObserver o)
- Prepares an image for rendering on this component at the specified width
and height.
- The image data is downloaded asynchronously in another thread and an
appropriately scaled screen representation of the image is generated.
- Parameters:
image
- the Image to prepare a screen representation for
width
- the width of the desired screen representation
height
- the height of the desired screen representation
observer
- the ImageObserver object to be notified as the image is being
prepared
- Returns:
- true if the image has already been fully prepared; false otherwise.
- See Also:
- ImageObserver (II-§2.11).
print
public abstract void print(Graphics g)
- Prints this component.
- The
coordinate of the graphics context is the top-left corner of the
components. The clipping region of the graphics context is the rectangle of
the component
- See Also:
- paint (II-§3.6.15).
repaint
public abstract void repaint(long tm, int x, int y,
int width, int height)
- Repaints the specified rectangle of the component.
- Parameters:
x
- the x coordinate
y
- the y coordinate
width
- the width
height
-
the height
- See Also:
- paint (II-§3.6.15).
requestFocus
public abstract void requestFocus()
- Requests the input focus.
reshape
public abstract void
reshape(int x, int y, int width, int height)
- Reshapes the component to the specified bounding rectangle.
- Parameters:
x
- the x coordinate
y
- the y coordinate
width
- the width of the component
height
- the height of the component
setBackground
public abstract void setBackground(Color c)
- Sets the background color for the component.
- Parameters:
c
- the color
setFont
public abstract void setFont(Font f)
- Sets the font of the component.
- Parameters:
f
- the font
setForeground
public abstract void setForeground(Color c)
- Sets the foreground color for the component.
- Parameters:
c
- the color
show
public abstract void show()
- Shows the component: if the component had been made invisible by a call
to the hide method (II-§3.6.12), make the component visible again.
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Java API Document (HTML generated by dkramer on April 22, 1996)
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