acm.graphics

Class GImage

java.lang.Object

acm.graphics.GObject

acm.graphics.GImage

All Implemented Interfaces:

GResizable, GScalable, Serializable, Cloneable

public class GImage
extends GObject
implements GResizable, GScalable

The GImage class is a graphical object whose appearance is defined by an image.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
GImage(Image image) Creates a new GImage object at the origin that displays the specified image.
GImage(Image image, double x, double y) Creates a new GImage object at the specified coordinates.
GImage(int[][] array) Creates a new GImage object at the origin.
GImage(int[][] array, double x, double y) Creates a new GImage object at the specified coordinates.
GImage(String name) Creates a new GImage object by looking for an image with that name.
GImage(String name, double x, double y) Creates a new GImage object at the specified coordinates.

Method Summary

Modifier and Type	Method and Description
static int	createRGBPixel(int red, int green, int blue) Creates an opaque pixel value with the color components given by red, green, and blue.
static int	createRGBPixel(int red, int green, int blue, int alpha) Creates a pixel value with the color components given by red, green, and blue and the transparency value alpha.
void	fit(double width, double height) Resizes the image to the largest size that fits within the given width/height while maintaining the image's "aspect ratio" (not stretching the image's relative width/height).
static int	getAlpha(int pixel) Returns the alpha component from an RGB value.
protected Rectangle	getAWTBounds() Returns an AWT Rectangle that specifies the bounds of this object.
static int	getBlue(int pixel) Returns the blue component from an RGB value.
GRectangle	getBounds() Returns the bounding box of this object.
static int	getGreen(int pixel) Returns the green component from an RGB value.
Image	getImage() Returns the image stored inside this GImage.
int[][]	getPixelArray() Returns a two-dimensional array of pixel values from the stored image.
static int	getRed(int pixel) Returns the red component from an RGB value.
acm.graphics.GDimension	getSize() Returns the size of this object as a GDimension.
boolean	inBounds(double x, double y) Returns whether the given x/y pixel position is within the bounds of the image, in other words, whether it is between (0, 0) and (w, h).
protected void	paint2d(Graphics2D graphics2d) Implements the paint2d operation for this graphical object.
void	saveImage(File file) Saves the image to the specified file.
void	saveImage(String filename) Saves the image to a file with the specified filename.
void	scale(double sx, double sy) Scales the object on the screen by the scale factors sx and sy.
void	setBounds(double x, double y, double width, double height) Changes the bounds of this object to the specified values.
void	setBounds(GRectangle bounds) Changes the bounds of this object to the values from the specified GRectangle.
void	setImage(Image image) Resets the image used by this GImage object to the new image specified as an argument.
void	setImage(String name) Resets the image used by this GImage object to the one identified by the argument name, which is processed exactly as described in the constructors.
void	setPixelArray(int[][] pixels) Sets the image to use the given two-dimensional array of pixel values.
void	setSize(double width, double height) Changes the size of this object to the specified width and height.
void	setSize(acm.graphics.GDimension size) Changes the size of this object to the specified GDimension.

Methods inherited from class acm.graphics.GObject

addActionListener, addMouseListener, addMouseMotionListener, areMouseListenersEnabled, clone, colorName, colorName, colorNameFriendly, contains, contains, createTransformedGraphics, fireActionEvent, fireActionEvent, fireMouseListeners, getBottomY, getCenterLocation, getCenterX, getCenterY, getColor, getComponent, getHeight, getLineWidth, getLocation, getMatrix, getObjectColor, getParent, getRightX, getWidth, getX, getY, intersects, isAntiAliasing, isVisible, move, movePolar, paint, paramString, pause, removeActionListener, removeMouseListener, removeMouseMotionListener, repaint, rotate, scale, sendBackward, sendForward, sendToBack, sendToFront, setAntiAliasing, setBottomY, setCenterLocation, setCenterLocation, setCenterX, setCenterY, setColor, setLineWidth, setLocation, setLocation, setParent, setRightX, setVisible, setX, setY, start, start, toString, updateEnabledList

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface acm.graphics.GScalable

scale

Constructor Detail

GImage

public GImage(Image image)

Creates a new GImage object at the origin that displays the specified image.

Parameters:

image - The image to use as the contents of this GImage

Usage:

GImage gimage = new GImage(image);

GImage

public GImage(String name)

Creates a new GImage object by looking for an image with that name. The search for an image by name consists of the following steps:

1. Check to see if an image with that name has already been defined. If so, return that image.

2. Check to see if there is a resource available with that name whose contents can be read as an Image. If so, read the image from the resource file.

3. Load the image from a file with the specified name, relative to the application directory or the applet code base.

Parameters:

name - The name used to search for the contents of this image

Usage:

GImage gimage = new GImage(name);

GImage

public GImage(int[][] array)

Creates a new GImage object at the origin. The array parameter is a two-dimensional pixel array in which each pixel value consists of an integer that is subdivided into four eight-bit bytes, as follows:

alpha << 24 | red << 16 | green << 8 | blue

The alpha value indicates the transparency, and the other values are the red, green, and blue components of the color.

Parameters:

array - A two-dimensional pixel array

Usage:

GImage gimage = new GImage(array);

GImage

public GImage(Image image,
              double x,
              double y)

Creates a new GImage object at the specified coordinates. The image parameter is used to initialize the appearance of the image.

Parameters:

image - The image to use as the contents of this GImage

x - The x-coordinate of the upper left corner of the image

y - The y-coordinate of the upper left corner of the image

Usage:

GImage gimage = new GImage(image, x, y);

GImage

public GImage(String name,
              double x,
              double y)

Creates a new GImage object at the specified coordinates. The name parameter is used to identify an image to display, as described in the single-argument version of the GImage constructor.

Parameters:

name - The name used to search for the contents of this image

x - The x-coordinate of the upper left corner of the image

y - The y-coordinate of the upper left corner of the image

Usage:

GImage gimage = new GImage(image, x, y);

GImage

public GImage(int[][] array,
              double x,
              double y)

Creates a new GImage object at the specified coordinates. The array parameter is a two-dimensional pixel array in which each pixel value consists of an integer that is subdivided into four eight-bit bytes, as follows:

alpha << 24 | red << 16 | green << 8 | blue

The alpha value indicates the transparency, and the other values are the red, green, and blue components of the color.

Parameters:

array - A two-dimensional pixel array

x - The x-coordinate of the upper left corner of the image

y - The y-coordinate of the upper left corner of the image

Usage:

GImage gimage = new GImage(array, x, y);

Method Detail

createRGBPixel

public static int createRGBPixel(int red,
                                 int green,
                                 int blue)

Creates an opaque pixel value with the color components given by red, green, and blue.

Parameters:

red - The red component of the pixel (0 to 255)

green - The green component of the pixel (0 to 255)

blue - The blue component of the pixel (0 to 255)

Returns:

An opaque pixel value containing these components

Usage:

int pixel = GImage.createRGBPixel(red, green, blue);

createRGBPixel

public static int createRGBPixel(int red,
                                 int green,
                                 int blue,
                                 int alpha)

Creates a pixel value with the color components given by red, green, and blue and the transparency value alpha.

Parameters:

red - The red component of the pixel (0 to 255)

green - The green component of the pixel (0 to 255)

blue - The blue component of the pixel (0 to 255)

alpha - The transparency value of the pixel (0 to 255)

Returns:

A pixel value containing these components

Usage:

int pixel = GImage.createRGBPixel(red, green, blue);

fit

public void fit(double width,
                double height)

Resizes the image to the largest size that fits within the given width/height while maintaining the image's "aspect ratio" (not stretching the image's relative width/height).

Parameters:

width - maximum width, in pixels

height - maximum height, in pixels

getAlpha

public static int getAlpha(int pixel)

Returns the alpha component from an RGB value.

Parameters:

pixel - An int containing a pixel value as alpha/red/green/blue.

Returns:

The alpha component of the pixel

Usage:

int alpha = GImage.getAlpha(pixel);

getAWTBounds

protected Rectangle getAWTBounds()

Returns an AWT Rectangle that specifies the bounds of this object.

Returns:

A Rectangle that specifies the bounds of this object

Usage:

Rectangle r = grect.getAWTBounds();

getBlue

public static int getBlue(int pixel)

Returns the blue component from an RGB value.

Parameters:

pixel - An int containing a pixel value as alpha/red/green/blue.

Returns:

The blue component of the pixel

Usage:

int blue = GImage.getBlue(pixel);

getBounds

public GRectangle getBounds()

Returns the bounding box of this object.

Specified by:

getBounds in class GObject

Returns:

The bounding box for this object

Usage:

GRectangle bounds = gimage.getBounds();

getGreen

public static int getGreen(int pixel)

Returns the green component from an RGB value.

Parameters:

pixel - An int containing a pixel value as alpha/red/green/blue.

Returns:

The green component of the pixel

Usage:

int green = GImage.getGreen(pixel);

getImage

public Image getImage()

Returns the image stored inside this GImage.

Returns:

The Image object stored inside this GImage

Usage:

Image image = gimage.getImage();

getRed

public static int getRed(int pixel)

Returns the red component from an RGB value.

Parameters:

pixel - An int containing a pixel value as alpha/red/green/blue.

Returns:

The red component of the pixel

Usage:

int red = GImage.getRed(pixel);

getSize

public acm.graphics.GDimension getSize()

Returns the size of this object as a GDimension.

Overrides:

getSize in class GObject

Returns:

The size of this object

Usage:

GDimension size = gimage.getSize();

inBounds

public boolean inBounds(double x,
                        double y)

Returns whether the given x/y pixel position is within the bounds of the image, in other words, whether it is between (0, 0) and (w, h).

Parameters:

x - the pixel's x-coordinate

y - the pixel's y-coordinate

Returns:

true if the given x/y pixel position is between (0, 0) and (w, h)

paint2d

protected void paint2d(Graphics2D graphics2d)

Implements the paint2d operation for this graphical object. This method is not called directly by clients.

Specified by:

paint2d in class GObject

Parameters:

graphics2d - The graphics context into which the painting is done

Noshow:

saveImage

public void saveImage(File file)

Saves the image to the specified file. The data format for the image file is determined by the suffix of the filename. If the suffix of the file is not recognized as a supported image type, calling this method generates an error.

Parameters:

file - The File to which the image is saved

Usage:

gimage.saveImage(file);

saveImage

public void saveImage(String filename)

Saves the image to a file with the specified filename. The data format for the image file is determined by the suffix of the filename. If the suffix of the file is not recognized as a supported image type, calling this method generates an error.

Parameters:

filename - The name of the file to which the image is saved

Usage:

gimage.saveImage(filename);

setBounds

public void setBounds(double x,
                      double y,
                      double width,
                      double height)

Changes the bounds of this object to the specified values.

Specified by:

setBounds in interface GResizable

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

Usage:

gimage.setBounds(x, y, width, height);

setBounds

public final void setBounds(GRectangle bounds)

Changes the bounds of this object to the values from the specified GRectangle.

Specified by:

setBounds in interface GResizable

Parameters:

bounds - A GRectangle specifying the new bounds

Usage:

gimage.setBounds(bounds);

setImage

public void setImage(Image image)

Resets the image used by this GImage object to the new image specified as an argument. Calling setImage automatically changes the size of the image to be equal to that of the image data.

Parameters:

image - The image to use as the contents of this GImage

Usage:

gimage.setImage(image);

setImage

public void setImage(String name)

Resets the image used by this GImage object to the one identified by the argument name, which is processed exactly as described in the constructors. Calling setImage automatically changes the size of the image to be equal to that of the image data.

Parameters:

name - The name used to search for the contents of this image

Usage:

gimage.setImage(name);

setSize

public void setSize(double width,
                    double height)

Changes the size of this object to the specified width and height.

Specified by:

setSize in interface GResizable

Parameters:

width - The new width of the object

height - The new height of the object

Usage:

gimage.setSize(width, height);

setSize

public final void setSize(acm.graphics.GDimension size)

Changes the size of this object to the specified GDimension.

Specified by:

setSize in interface GResizable

Parameters:

size - A GDimension object specifying the size

Usage:

gimage.setSize(size);

Noshow:

scale

public void scale(double sx,
                  double sy)

Scales the object on the screen by the scale factors sx and sy.

Specified by:

scale in interface GScalable

Overrides:

scale in class GObject

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

Usage:

gobj.scale(sx, sy);

getPixelArray

public int[][] getPixelArray()

Returns a two-dimensional array of pixel values from the stored image.

Returns:

A two-dimensional array of pixel values from the stored image

Usage:

int[][] array = gimage.getPixelArray();

setPixelArray

public void setPixelArray(int[][] pixels)

Sets the image to use the given two-dimensional array of pixel values.

Usage:

gimage.setPixelArray(array);