GObject

java.lang.Object
- stanford.androidlib.graphics.GObject

Direct Known Subclasses:

GCompound, GImage, GLabel, GLine, GOval, GPolygon, GRect, GSprite
```
public abstract class GObject
extends Object
```
GObject is the superclass for all of the various kinds of graphical objects such as lines, ovals, rectangles, ellipses, and other polygons.

Constructor Summary

Constructors
Constructor and Description

GObject()
Constructs a new empty object.

GObject(GCanvas canvas)
Constructs a new empty object and adds it to the given canvas.

Constructors
Constructor and Description
`GObject()` Constructs a new empty object.
`GObject(GCanvas canvas)` Constructs a new empty object and adds it to the given canvas.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`GObject`	`addTo(GCanvas canvas)` Adds this GObject to the given graphical canvas.
`GObject`	`addTo(GCanvas canvas, float x, float y)` Adds this GObject to the given graphical canvas.
`GObject`	`addTo(GCanvas canvas, GPoint location)` Adds this GObject to the given graphical canvas.
`boolean`	`contains(float x, float 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.
`float`	`getBottomY()` Returns the max Y of this object.
`GRectangle`	`getBounds()` Returns the bounding box of this object, which is defined to be the smallest rectangle that covers everything drawn by the figure.
`float`	`getCenterX()` Returns the x-value of the center of this object.
`float`	`getCenterY()` Returns the y-value of the center of this object.
`Paint`	`getColor()` Returns the color used to display this object.
`Paint`	`getFillColor()` Returns the color used to display the filled region of this object.
`GCanvas`	`getGCanvas()` Returns the simple canvas this GObject is drawn inside of.
`float`	`getHeight()` Returns the height of this object, which is defined to be the height of the bounding box.
`float`	`getLeftX()` Returns this object's leftmost x-coordinate.
`GPoint`	`getLocation()` Returns the location of this object as a GPoint.
`Paint`	`getPaint()` Returns the color used to display this object.
`float`	`getRightX()` Returns the max X of this object.
`GDimension`	`getSize()` Returns the size of the bounding box for this object.
`float`	`getTopY()` Returns this object's top y-coordinate.
`float`	`getWidth()` Returns the width of this object, which is defined to be the width of the bounding box.
`float`	`getX()` Returns the x-coordinate of the object.
`float`	`getY()` Returns the y-coordinate of the object.
`boolean`	`intersects(GObject obj)` True if this object touches the other object.
`boolean`	`isFilled()` Returns whether this object is filled.
`boolean`	`isVisible()` Checks to see whether this object is visible.
`GObject`	`moveBy(float dx, float dy)` Moves the object on the screen using the displacements dx and dy.
`GObject`	`moveByPolar(float r, float theta)` Moves the object using displacements given in polar coordinates.
`GObject`	`moveTo(float x, float y)` Moves the object on the screen to the given x/y position.
`GObject`	`moveTo(GObject gobj)` Moves this GObject to have the same location as the given other GObject.
`GObject`	`moveTo(GPoint point)` Moves the object on the screen to the given point's x/y position.
`GObject`	`moveToPolar(float r, float theta)` Moves the object using displacements given in polar coordinates.
`abstract void`	`paint(Canvas canvas)` 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.
`GObject`	`remove()` Removes this object from its graphical canvas, if it is added to one.
`void`	`repaint()` Instructs this object to redraw itself by calling the postInvalidate method on its enclosing GCanvas as needed.
`GObject`	`scale(float sf)` Scales the object on the screen by the scale factor `sf`, which applies in both dimensions.
`GObject`	`scale(float sx, float sy)` Scales the object on the screen by the scale factors `sx` and `sy`.
`GObject`	`sendBackward()` Moves this object one step toward the back in the z dimension.
`GObject`	`sendForward()` Moves this object one step toward the front in the z dimension.
`GObject`	`sendToBack()` Moves this object to the back of the display in the z dimension.
`GObject`	`sendToFront()` Moves this object to the front of the display in the z dimension.
`GObject`	`setBottomY(float bottomY)` Sets the object's bottom y-coordinate to be the given value.
`GObject`	`setBounds(float x, float y, float width, float height)` Changes the bounds of this object to the specified values.
`GObject`	`setBounds(GPoint location, GDimension size)` Changes the bounds of this object to the specified values.
`GObject`	`setBounds(GRectangle bounds)` Changes the bounds of this object to the values from the specified `GRectangle`.
`GObject`	`setCanvas(Canvas canvas)` Sets the canvas this object is in.
`GObject`	`setColor(Paint paint)` Sets the color used to display this object.
`GObject`	`setFillColor(Paint color)` Sets the color used to display the filled region of this object.
`GObject`	`setFilled(boolean fill)` Sets whether this object is filled.
`GObject`	`setGCanvas(GCanvas gcanvas)` Sets the canvas on which this GObject should be drawn.
`GObject`	`setLocation(float x, float y)` Sets the location of this object to the point (x, y).
`GObject`	`setLocation(GObject gobj)` Moves this GObject to have the same location as the given other GObject.
`GObject`	`setLocation(GPoint point)` Sets the location of this object to the given point's (x, y) location.
`GObject`	`setPaint(Paint paint)` Sets the paint used to display this object.
`GObject`	`setRightX(float rightX)` Sets the object's rightmost x-coordinate to be the given value.
`GObject`	`setSize(float width, float height)` Changes the size of this object to the specified width and height.
`GObject`	`setSize(GDimension size)` Changes the size of this object to the specified `GDimension`.
`GObject`	`setVisible(boolean visible)` Sets whether this object is visible.
`GObject`	`setX(float x)` Sets the x-location of this object.
`GObject`	`setY(float y)` Sets the y-location of this object.
`String`	`toString()` Returns a string representation of this object, including its class name, x/y coordinates, width, and height.
`GObject`	`translate(float dx, float dy)` Moves the object on the screen using the displacements dx and dy.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - GObject
```
public GObject()
```
    Constructs a new empty object.
  - GObject
```
public GObject(GCanvas canvas)
```
    Constructs a new empty object and adds it to the given canvas.
- Method Detail
  - addTo
```
public GObject addTo(GCanvas canvas)
```
    Adds this GObject to the given graphical canvas. A convenience method that just calls the canvas's add(GObject) method.
  - addTo
```
public GObject addTo(GCanvas canvas,
                     float x,
                     float y)
```
    Adds this GObject to the given graphical canvas. A convenience method that just calls the canvas's add(GObject) method.
  - addTo
```
public GObject addTo(GCanvas canvas,
                     GPoint location)
```
    Adds this GObject to the given graphical canvas. A convenience method that just calls the canvas's add(GObject) method.
  - contains
```
public boolean contains(float x,
                        float y)
```
    Checks to see whether a point is inside the object.
  - contains
```
public boolean contains(GPoint pt)
```
    Checks to see whether a point is inside the object.
    
    Throws:
    
    NullPointerException - if pt is null
  - getBottomY
```
public final float getBottomY()
```
    Returns the max Y of this object.
  - getBounds
```
public GRectangle getBounds()
```
    Returns the bounding box of this object, which is defined to be the smallest rectangle that covers everything drawn by the figure.
  - getCenterX
```
public final float getCenterX()
```
    Returns the x-value of the center of this object.
  - getCenterY
```
public final float getCenterY()
```
    Returns the y-value of the center of this object.
  - getColor
```
public final Paint getColor()
```
    Returns the color used to display this object.
  - getFillColor
```
public final Paint getFillColor()
```
    Returns the color used to display the filled region of this object. If none has been set, getFillColor returns the color of the object.
    
    Returns:
    
    The color used to display the filled region of this object
    
    Usage:
    
    Color color = gobj.getFillColor();
  - getGCanvas
```
public final GCanvas getGCanvas()
```
    Returns the simple canvas this GObject is drawn inside of. If none, returns null.
  - getHeight
```
public float getHeight()
```
    Returns the height of this object, which is defined to be the height of the bounding box.
  - getLeftX
```
public float getLeftX()
```
    Returns this object's leftmost x-coordinate.
  - getLocation
```
public final GPoint getLocation()
```
    Returns the location of this object as a GPoint.
  - getPaint
```
public final Paint getPaint()
```
    Returns the color used to display this object.
  - getRightX
```
public final float getRightX()
```
    Returns the max X of this object.
  - getSize
```
public final GDimension getSize()
```
    Returns the size of the bounding box for this object.
  - getTopY
```
public float getTopY()
```
    Returns this object's top y-coordinate.
  - getWidth
```
public float getWidth()
```
    Returns the width of this object, which is defined to be the width of the bounding box.
  - getX
```
public float getX()
```
    Returns the x-coordinate of the object.
  - getY
```
public float getY()
```
    Returns the y-coordinate of the object.
  - intersects
```
public final boolean intersects(GObject obj)
```
    True if this object touches the other object.
    
    Throws:
    
    NullPointerException - if obj is null
  - isFilled
```
public final boolean isFilled()
```
    Returns whether this object is filled.
    
    Returns:
    
    The color used to display the object
    
    Usage:
    
    if (gobj.isFilled()) . . .
  - isVisible
```
public final boolean isVisible()
```
    Checks to see whether this object is visible.
  - moveBy
```
public final GObject moveBy(float dx,
                            float dy)
```
    Moves the object on the screen using the displacements dx and dy.
  - moveByPolar
```
public final GObject moveByPolar(float r,
                                 float theta)
```
    Moves the object using displacements given in polar coordinates.
  - moveTo
```
public GObject moveTo(float x,
                      float y)
```
    Moves the object on the screen to the given x/y position.
  - moveTo
```
public final GObject moveTo(GObject gobj)
```
    Moves this GObject to have the same location as the given other GObject.
    
    Throws:
    
    NullPointerException - if gobj is null
  - moveTo
```
public GObject moveTo(GPoint point)
```
    Moves the object on the screen to the given point's x/y position.
  - moveToPolar
```
public final GObject moveToPolar(float r,
                                 float theta)
```
    Moves the object using displacements given in polar coordinates.
  - paint
```
public abstract void paint(Canvas canvas)
```
    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.
  - remove
```
public GObject remove()
```
    Removes this object from its graphical canvas, if it is added to one. Equivalent to calling remove(thisGObject) on the canvas.
  - repaint
```
public void repaint()
```
    Instructs this object to redraw itself by calling the postInvalidate method on its enclosing GCanvas as needed.
  - scale
```
public GObject scale(float sx,
                     float sy)
```
    Scales the object on the screen by the scale factors sx and sy.
    
    Parameters:
    
    sx - The factor used to scale all coordinates in the x direction
    
    sy - The factor used to scale all coordinates in the y direction
    
    Throws:
    
    IllegalArgumentException - if sx or sy is not a positive number
    
    Usage:
    
    gobj.scale(sx, sy);
  - scale
```
public GObject scale(float sf)
```
    Scales the object on the screen by the scale factor sf, which applies in both dimensions.
    
    Parameters:
    
    sf - The factor used to scale all coordinates in both dimensions
    
    Throws:
    
    IllegalArgumentException - if sf is not a positive number
    
    Usage:
    
    gobj.scale(sf);
  - sendBackward
```
public final GObject sendBackward()
```
    Moves this object one step toward the back in the z dimension.
  - sendForward
```
public final GObject sendForward()
```
    Moves this object one step toward the front in the z dimension.
  - sendToBack
```
public final GObject sendToBack()
```
    Moves this object to the back of the display in the z dimension.
  - sendToFront
```
public final GObject sendToFront()
```
    Moves this object to the front of the display in the z dimension.
  - setBottomY
```
public GObject setBottomY(float bottomY)
```
    Sets the object's bottom y-coordinate to be the given value. This does not resize the object but moves it as though you had set its top y-coordinate to bottomY - getHeight().
  - setBounds
```
public GObject setBounds(float x,
                         float y,
                         float width,
                         float height)
```
    Changes the bounds of this object to the specified values.
    
    Parameters:
    
    x - The new x-coordinate for the object
    
    y - The new y-coordinate for the object
    
    width - The new width of the object
    
    height - The new height of the object
    
    Throws:
    
    IllegalArgumentException - if width or height is negative
    
    Usage:
    
    gimage.setBounds(x, y, width, height);
  - setBounds
```
public GObject setBounds(GPoint location,
                         GDimension size)
```
    Changes the bounds of this object to the specified values.
    
    Parameters:
    
    location - The new x/y-coordinates for the object
    
    size - The new width/height of the object
    
    Throws:
    
    IllegalArgumentException - if width or height is negative
    
    Usage:
    
    gimage.setBounds(x, y, width, height);
  - setBounds
```
public GObject setBounds(GRectangle bounds)
```
    Changes the bounds of this object to the values from the specified GRectangle.
    
    Parameters:
    
    bounds - A GRectangle specifying the new bounds
    
    Throws:
    
    IllegalArgumentException - if rect's width or height is negative
    
    Usage:
    
    gimage.setBounds(bounds);
  - setCanvas
```
public final GObject setCanvas(Canvas canvas)
```
    Sets the canvas this object is in. If null is passed, this object will not be associated with any canvas.
  - setColor
```
public GObject setColor(Paint paint)
```
    Sets the color used to display this object. This differs slightly from setPaint in that setPaint replaces ALL aspects of the paint, while setColor changes this object's color while retaining any other aspects of the paint such as font size.
    
    Throws:
    
    NullPointerException - if paint is null.
  - setFillColor
```
public GObject setFillColor(Paint color)
```
    Sets the color used to display the filled region of this object.
    
    Parameters:
    
    color - The color used to display the filled region of this object
    
    Throws:
    
    NullPointerException - if color is null
    
    Usage:
    
    gobj.setFillColor(color);
  - setFilled
```
public GObject setFilled(boolean fill)
```
    Sets whether this object is filled.
    
    Parameters:
    
    fill - true if the object should be filled, false for an outline
    
    Usage:
    
    gobj.setFilled(fill);
  - setGCanvas
```
public GObject setGCanvas(GCanvas gcanvas)
```
    Sets the canvas on which this GObject should be drawn. You probably should not call this directly, and should call add(GObject) on the canvas instead. If gcanvas is null, this object will not be associated with any canvas.
  - setLocation
```
public GObject setLocation(float x,
                           float y)
```
    Sets the location of this object to the point (x, y).
  - setLocation
```
public GObject setLocation(GPoint point)
```
    Sets the location of this object to the given point's (x, y) location.
  - setLocation
```
public GObject setLocation(GObject gobj)
```
    Moves this GObject to have the same location as the given other GObject.
    
    Throws:
    
    NullPointerException - if gobj is null.
  - setPaint
```
public GObject setPaint(Paint paint)
```
    Sets the paint used to display this object. This differs slightly from setColor in that setPaint replaces ALL aspects of the paint, while setColor changes this object's color while retaining any other aspects of the paint such as font size.
    
    Throws:
    
    NullPointerException - if paint is null.
  - setRightX
```
public GObject setRightX(float rightX)
```
    Sets the object's rightmost x-coordinate to be the given value. This does not resize the object but moves it as though you had set its leftmost x-coordinate to rightX - getWidth().
  - setSize
```
public GObject setSize(GDimension size)
```
    Changes the size of this object to the specified GDimension.
    
    Parameters:
    
    size - A GDimension object specifying the size
    
    Throws:
    
    NullPointerException - if size is null
    
    Usage:
    
    gimage.setSize(size);
    
    Noshow:
  - setSize
```
public GObject setSize(float width,
                       float height)
```
    Changes the size of this object to the specified width and height.
    
    Parameters:
    
    width - The new width of the object
    
    height - The new height of the object
    
    Throws:
    
    IllegalArgumentException - if width or height is negative
    
    Usage:
    
    gimage.setSize(width, height);
  - setVisible
```
public GObject setVisible(boolean visible)
```
    Sets whether this object is visible.
  - setX
```
public GObject setX(float x)
```
    Sets the x-location of this object. The y-location is unchanged.
  - setY
```
public GObject setY(float y)
```
    Sets the y-location of this object. The x-location is unchanged.
  - toString
```
public String toString()
```
    Returns a string representation of this object, including its class name, x/y coordinates, width, and height. Useful for debugging.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string representation of the object.
  - translate
```
public GObject translate(float dx,
                         float dy)
```
    Moves the object on the screen using the displacements dx and dy.

Class GObject

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

GObject

GObject

Method Detail

addTo

addTo

addTo

contains

contains

getBottomY

getBounds

getCenterX

getCenterY

getColor

getFillColor

getGCanvas

getHeight

getLeftX

getLocation

getPaint

getRightX

getSize

getTopY

getWidth

getX

getY

intersects

isFilled

isVisible

moveBy

moveByPolar

moveTo

moveTo

moveTo

moveToPolar

paint

remove

repaint

scale

scale

sendBackward

sendForward

sendToBack

sendToFront

setBottomY

setBounds

setBounds

setBounds

setCanvas

setColor

setFillColor

setFilled

setGCanvas

setLocation

setLocation

setLocation

setPaint

setRightX

setSize

setSize

setVisible

setX

setY

toString

translate