Package edu.macalester.graphics

Class Image

java.lang.Object

edu.macalester.graphics.GraphicsObject

edu.macalester.graphics.Image

public class Image
extends GraphicsObject

A bitmap image that can be drawn to the screen.

An image’s position is the upper left corner of its bounding box. Its size is the size of the underying image file by default, but you can shrink it using setMaxWidth() and setMaxHeight().

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	Image.PixelFormat	Describes the presence and order of color channels in an array of pixels.

Constructor Summary

Constructors

Constructor	Description
Image(double x, double y)	Creates an Image placeholder with no current image.
Image(double x, double y, BufferedImage image)	Creates a bitmap image from the given BufferedImage.
Image(double x, double y, String path)	Creates a bitmap image from the given file.
Image(int width, int height, byte[] pixels, Image.PixelFormat format)	Creates a new image using raw pixel data from the given array.
Image(int width, int height, float[] pixels, Image.PixelFormat format)	Creates a new image using raw pixel data from the given array.
Image(int width, int height, int[] pixels)	Creates a new image using raw pixel data from the given array, one int per pixel.
Image(BufferedImage image)	Creates a bitmap image from the given BufferedImage, positioned at (0, 0).
Image(String path)	Creates a bitmap image from the given file, positioned at (0,0).

Method Summary

Modifier and Type	Method	Description
protected void	drawInLocalCoordinates(Graphics2D gc)	For internal use.
Rectangle2D	getBounds()	Returns the bounding box of this graphics object in its local coordinates.
protected Object	getEqualityAttributes()	For internal use only.
int	getImageHeight()	Get the height of the underlying image in pixels.
int	getImageWidth()	Get the width of the underlying image in pixels.
void	setImagePath(String path)	Changes the image displayed by this graphics element.
void	setMaxHeight(double maxHeight)	Causes the image to shrink (preserving aspect ratio) if the image height is larger than the given maximum height.
void	setMaxWidth(double maxWidth)	Causes the image to shrink (preserving aspect ratio) if the image width is larger than the given maximum width.
boolean	testHitInLocalCoordinates(double x, double y)	Tests whether the point (x, y) touches the image.
byte[]	toByteArray(Image.PixelFormat format)	Returns the pixels in this image as an array of bytes, one byte per color channel per pixel, interleaved in the order specified by format.
float[]	toFloatArray(Image.PixelFormat format)	Returns the pixels in this image as an array of floats, one number per color channel per pixel, interleaved in the order specified by format.
int[]	toIntArray()	Returns the pixels in this image as an array of ints, one int per pixel.
String	toString()

Methods inherited from class edu.macalester.graphics.GraphicsObject

addObserver, changed, equals, getAnchor, getBoundsInParent, getCanvas, getCenter, getElementAt, getElementAtLocalCoordinates, getEmbeddedComponent, getHeight, getParent, getPosition, getRotation, getScale, getScaleX, getScaleY, getSize, getSizeInParent, getWidth, getX, getY, hashCode, isInBounds, moveBy, moveBy, removeObserver, renderToBuffer, rotateBy, setAnchor, setAnchor, setCenter, setCenter, setPosition, setPosition, setRotation, setScale, setScale, setScale, setX, setY, testHit

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

Image

public Image(double x,
 double y)

Creates an Image placeholder with no current image.

Image

public Image(String path)

Creates a bitmap image from the given file, positioned at (0,0). Acceptable file formats include: GIF, PNG, JPEG, BMP, and WBMP.

Parameters:

path - path of image file to load, relative to the res/ directory.

Image

public Image(double x,
 double y,
 String path)

Creates a bitmap image from the given file. Acceptable file formats include: GIF, PNG, JPEG, BMP, and WBMP.

Parameters:

path - path of image file to load, relative to the res/ directory.

Image

public Image(int width,
 int height,
 float[] pixels,
 Image.PixelFormat format)

Creates a new image using raw pixel data from the given array. The range for sample values is [0...1], and values outside that range are pinned to it when generating the image (i.e. any value ≥ 1 is full intensity, and any value ≤ 0 is zero intensity). There is one array element per color channel, with channels interleaved (see Image.PixelFormat.)

For example, the array { 1, 0.5f, 0, 0, 0, 0.5f } with the RGB pixel format specifies one orange pixel (R=100%, G=50%, B=0%), then one dark blue pixel (R=0%, G=0%, B=50%).

Parameters:

width - Image width in pixels

height - Image height in pixels

pixels - Raw pixel data. Length must exactly match the number of required samples.

format - Color space and format of channels in the pixels array

Image

public Image(int width,
 int height,
 byte[] pixels,
 Image.PixelFormat format)

Creates a new image using raw pixel data from the given array. This interprets bytes as unsigned: zero intensity is 0, and full intensity is 255 (but Java represents this as -1, because the language does not have unsigned primitive types). There is one array element per color channel, with channels interleaved (see Image.PixelFormat.)

For example, the array { -1, 127, 0, 0, 0, 127 } with the RGB pixel format specifies one orange pixel (R=100%, G=50%, B=0%), then one dark blue pixel (R=0%, G=0%, B=50%).

Parameters:

width - Image width in pixels

height - Image height in pixels

pixels - Raw pixel data. Length must exactly match the number of required samples.

format - Color space and format of channels in the pixels array

Image

public Image(int width,
 int height,
 int[] pixels)

Creates a new image using raw pixel data from the given array, one int per pixel. Each pixel is in 32-bit ARGB format.

Parameters:

width - Image width in pixels

height - Image height in pixels

pixels - Raw pixel data. Length must exactly match the number of required samples.

Image

public Image(BufferedImage image)

Creates a bitmap image from the given BufferedImage, positioned at (0, 0). Note that changing the BufferedImage externally does not automatically force it to redraw. You will need to call CanvasWindow.draw() to see the changes.

Image

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

Creates a bitmap image from the given BufferedImage. Note that changing the BufferedImage externally does not automatically force it to redraw. You will need to call CanvasWindow.draw() to see the changes.

Method Details

setImagePath

public void setImagePath(String path)

Changes the image displayed by this graphics element.

Parameters:

path - path of image file to load, relative to the res/ directory.

setMaxWidth

public void setMaxWidth(double maxWidth)

Causes the image to shrink (preserving aspect ratio) if the image width is larger than the given maximum width.

setMaxHeight

public void setMaxHeight(double maxHeight)

Causes the image to shrink (preserving aspect ratio) if the image height is larger than the given maximum height.

drawInLocalCoordinates

protected void drawInLocalCoordinates(Graphics2D gc)

Description copied from class: GraphicsObject

For internal use. Draws this graphics object on the screen in its local coordinates, without rotation or scaling.

Specified by:

drawInLocalCoordinates in class GraphicsObject

getImageWidth

public int getImageWidth()

Get the width of the underlying image in pixels.

getImageHeight

public int getImageHeight()

Get the height of the underlying image in pixels.

testHitInLocalCoordinates

public boolean testHitInLocalCoordinates(double x,
 double y)

Tests whether the point (x, y) touches the image. Does not take into account image transparency.

Specified by:

testHitInLocalCoordinates in class GraphicsObject

getBounds

public Rectangle2D getBounds()

Description copied from class: GraphicsObject

Returns the bounding box of this graphics object in its local coordinates.

Specified by:

getBounds in class GraphicsObject

toByteArray

public byte[] toByteArray(Image.PixelFormat format)

Returns the pixels in this image as an array of bytes, one byte per color channel per pixel, interleaved in the order specified by format. Zero is minimum intensity, and 255 (or -1, since bytes are signed) is full intensity.

Note that when requesting a grayscale image, this method averages the color channels, which produces results that correspond poorly to perceived brightness.

See Also:

• Image(int,int,byte[],PixelFormat)
• toFloatArray(PixelFormat)
• toIntArray()

toFloatArray

public float[] toFloatArray(Image.PixelFormat format)

Returns the pixels in this image as an array of floats, one number per color channel per pixel, interleaved in the order specified by format. Zero is minimum intensity, and 1 is full intensity.

Note that when requesting a grayscale image, this method averages the color channels, which produces results that correspond poorly to perceived brightness.

See Also:

• Image(int,int,float[],PixelFormat)
• toByteArray(PixelFormat)

toIntArray

public int[] toIntArray()

Returns the pixels in this image as an array of ints, one int per pixel. Pixels use 32-bit ARGB encoding.

Note that the other methods that convert images to arrays return one array entry per color channel, while this method returns one array entry per pixel.

See Also:

• Image(int,int,byte[],PixelFormat)
• toFloatArray(PixelFormat)

getEqualityAttributes

protected Object getEqualityAttributes()

Description copied from class: GraphicsObject

For internal use only. Used to compute equals() and hashCode(). Returns an object whose equals() and hashCode() methods encompass the subclass-specific values that should be used to compute equality for the whole GraphicsObject.

Specified by:

getEqualityAttributes in class GraphicsObject

toString

public String toString()

Overrides:

toString in class Object