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java.lang.Object acm.graphics.GObject
public abstract class GObject
This class is the common superclass of all graphical objects that can
be displayed on a GCanvas
.
Because it is an abstract class, you are not allowed to construct an
object whose class is GObject
directly. What you do
instead is construct one of the concrete subclasses like
GRect
or
GLine
.
The purpose of this class definition is to define methods that apply
to all graphical objects regardless of their specific class.
The GObject
class implements the Serializable
interface by saving all of the internal state of the object. The parent,
however, is saved only if the parent is a GCompound
.
Method Summary | |
---|---|
void |
addActionListener(ActionListener listener)
Adds an action listener to this graphical object. |
void |
addMouseListener(MouseListener listener)
Adds a mouse listener to this graphical object. |
void |
addMouseMotionListener(MouseMotionListener listener)
Adds a mouse motion listener to this graphical object. |
boolean |
contains(double x,
double y)
Checks to see whether a point is inside the object. |
boolean |
contains(GPoint pt)
Checks to see whether a point is inside the object. |
void |
fireActionEvent(ActionEvent e)
Triggers an action event for this graphical object. |
void |
fireActionEvent(String actionCommand)
Triggers an action event for this graphical object with the specified action command. |
abstract GRectangle |
getBounds()
Returns the bounding box of this object, which is defined to be the smallest rectangle that covers everything drawn by the figure. |
Color |
getColor()
Returns the color used to display this object. |
double |
getHeight()
Returns the height of this object, which is defined to be the height of the bounding box. |
GPoint |
getLocation()
Returns the location of this object as a GPoint . |
GContainer |
getParent()
Returns the parent of this object, which is the canvas or compound object in which it is enclosed. |
GDimension |
getSize()
Returns the size of the bounding box for this object. |
double |
getWidth()
Returns the width of this object, which is defined to be the width of the bounding box. |
double |
getX()
Returns the x-coordinate of the object. |
double |
getY()
Returns the y-coordinate of the object. |
boolean |
isVisible()
Checks to see whether this object is visible. |
void |
move(double dx,
double dy)
Moves the object on the screen using the displacements dx and dy . |
void |
movePolar(double r,
double theta)
Moves the object using displacements given in polar coordinates. |
abstract void |
paint(Graphics g)
All subclasses of GObject must define a paint
method which allows the object to draw itself on the Graphics
context passed in as the parameter g . |
void |
pause(double milliseconds)
Delays the calling thread for the specified time, which is expressed in milliseconds. |
void |
removeActionListener(ActionListener listener)
Removes an action listener from this graphical object. |
void |
removeMouseListener(MouseListener listener)
Removes a mouse listener from this graphical object. |
void |
removeMouseMotionListener(MouseMotionListener listener)
Removes a mouse motion listener from this graphical object. |
void |
sendBackward()
Moves this object one step toward the back in the z dimension. |
void |
sendForward()
Moves this object one step toward the front in the z dimension. |
void |
sendToBack()
Moves this object to the back of the display in the z dimension. |
void |
sendToFront()
Moves this object to the front of the display in the z dimension. |
void |
setColor(Color color)
Sets the color used to display this object. |
void |
setLocation(double x,
double y)
Sets the location of this object to the point ( x , y ). |
void |
setLocation(GPoint pt)
Sets the location of this object to the specified point. |
void |
setParent(GContainer parent)
Sets the parent of this object, which should be called only by the GContainer in which this is installed. |
void |
setVisible(boolean visible)
Sets whether this object is visible. |
String |
toString()
Overrides the toString method in Object to produce
more readable output. |
Methods inherited from class java.lang.Object |
---|
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Method Detail |
---|
public abstract void paint(Graphics g)
GObject
must define a paint
method which allows the object to draw itself on the Graphics
context passed in as the parameter g
.
g
- The graphics context into which the painting is donepublic abstract GRectangle getBounds()
getLocation
.
Given a GLabel
object, for
example, getLocation
returns the coordinates of the point on the baseline at which the
string begins; getBounds
, by contrast, returns a
rectangle that covers the entire window area occupied by the string.
public void setLocation(double x, double y)
x
, y
).
x
- The new x-coordinate for the objecty
- The new y-coordinate for the objectpublic final void setLocation(GPoint pt)
pt
- The new location for this objectpublic GPoint getLocation()
GPoint
.
GPoint
public double getX()
public double getY()
public void move(double dx, double dy)
dx
and dy
.
dx
- The distance to move the object in the x direction (positive is rightward)dy
- The distance to move the object in the y direction (positive is downward)public final void movePolar(double r, double theta)
r
specifies the distance to move and theta
specifies the angle in which the motion occurs. The angle is measured in
degrees increasing counterclockwise from the +x axis.
r
- The distance to movetheta
- The angle in which to move, measured in degrees
increasing counterclockwise from the +x axispublic GDimension getSize()
public double getWidth()
public double getHeight()
public boolean contains(double x, double y)
x
- The x-coordinate of the point being testedy
- The y-coordinate of the point being tested
true
if the point (x
, y
) is inside
the object, and false
otherwisepublic final boolean contains(GPoint pt)
pt
- The point being tested
true
if the point is inside the object, and false
otherwisepublic void sendToFront()
public void sendToBack()
public void sendForward()
public void sendBackward()
public void setColor(Color color)
color
- The color used to display this objectpublic Color getColor()
public void setVisible(boolean visible)
visible
- true
to make the object visible, false
to hide itpublic boolean isVisible()
true
if the object is visible, otherwise false
public String toString()
toString
method in Object
to produce
more readable output.
toString
in class Object
public GContainer getParent()
public void pause(double milliseconds)
Thread.sleep
, this method never throws an
exception.
milliseconds
- The sleep time in millisecondspublic void addMouseListener(MouseListener listener)
listener
- Any object that implements the MouseListener
interfacepublic void removeMouseListener(MouseListener listener)
listener
- The listener object to removepublic void addMouseMotionListener(MouseMotionListener listener)
listener
- Any object that implements the MouseMotionListener
interfacepublic void removeMouseMotionListener(MouseMotionListener listener)
listener
- The listener object to removepublic void addActionListener(ActionListener listener)
listener
- Any object that implements the ActionListener
interfacepublic void removeActionListener(ActionListener listener)
listener
- The listener object to removepublic void fireActionEvent(String actionCommand)
actionCommand
- The action command to include in the eventpublic void fireActionEvent(ActionEvent e)
e
- The ActionEvent
to firepublic void setParent(GContainer parent)
GContainer
in which this is installed. The
serialization behavior of the parent data depends on the parent
type. Because a GCompound
is serializable, it
needs to be maintained in a nontransient variable; other parent
classes are transient, so that these parents are not recorded
in the serial form.
|
Last updated: Sat, Aug 22, 2009 10:26 PM EDT | |||||||||
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