org.openscience.jmol.app
Class PngEncoder

java.lang.Object
  org.openscience.jmol.app.PngEncoder

public class PngEncoder
extends java.lang.Object

PngEncoder takes a Java Image object and creates a byte string which can be saved as a PNG file. The Image is presumed to use the DirectColorModel. Thanks to Jay Denny at KeyPoint Software http://www.keypoint.com/ who let me develop this code on company time. You may contact me with (probably very-much-needed) improvements, comments, and bug fixes at: david@catcode.com

Version:

1.4, 31 March 2000

Author:

J. David Eisenberg, http://catcode.com/pngencoder/, Christian Ribeaud (christian.ribeaud@genedata.com)

Field Summary

static boolean	ENCODE_ALPHA Constant specifying that alpha channel should be encoded.
static int	FILTER_LAST
static int	FILTER_NONE Constants for filters
static int	FILTER_SUB
static int	FILTER_UP
static boolean	NO_ALPHA Constant specifying that alpha channel should not be encoded.

Constructor Summary

PngEncoder()
Class constructor

PngEncoder(java.awt.Image image)
Class constructor specifying Image to encode, with no alpha channel encoding.

PngEncoder(java.awt.Image image, boolean encodeAlpha)
Class constructor specifying Image to encode, and whether to encode alpha.

PngEncoder(java.awt.Image image, boolean encodeAlpha, int whichFilter)
Class constructor specifying Image to encode, whether to encode alpha, and filter to use.

PngEncoder(java.awt.Image image, boolean encodeAlpha, int whichFilter, int compLevel)
Class constructor specifying Image source to encode, whether to encode alpha, filter to use, and compression level.

Method Summary

int	getCompressionLevel() Retrieve compression level
boolean	getEncodeAlpha() Retrieve alpha encoding status.
int	getFilter() Retrieve filtering scheme
byte[]	pngEncode() Creates an array of bytes that is the PNG equivalent of the current image.
byte[]	pngEncode(boolean encodeAlpha) Creates an array of bytes that is the PNG equivalent of the current image, specifying whether to encode alpha or not.
void	setCompressionLevel(int level) Set the compression level to use
void	setEncodeAlpha(boolean encodeAlpha) Set the alpha encoding on or off.
void	setFilter(int whichFilter) Set the filter to use
void	setImage(java.awt.Image image) Set the image to be encoded

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ENCODE_ALPHA

public static final boolean ENCODE_ALPHA

Constant specifying that alpha channel should be encoded.

See Also:

Constant Field Values

NO_ALPHA

public static final boolean NO_ALPHA

Constant specifying that alpha channel should not be encoded.

See Also:

Constant Field Values

FILTER_NONE

public static final int FILTER_NONE

Constants for filters

See Also:

Constant Field Values

FILTER_SUB

public static final int FILTER_SUB

See Also:

Constant Field Values

FILTER_UP

public static final int FILTER_UP

See Also:

Constant Field Values

FILTER_LAST

public static final int FILTER_LAST

See Also:

Constant Field Values

Constructor Detail

PngEncoder

public PngEncoder()

Class constructor

PngEncoder

public PngEncoder(java.awt.Image image)

Class constructor specifying Image to encode, with no alpha channel encoding.

Parameters:

image - A Java Image object which uses the DirectColorModel

See Also:

Image

PngEncoder

public PngEncoder(java.awt.Image image,
                  boolean encodeAlpha)

Class constructor specifying Image to encode, and whether to encode alpha.

Parameters:

image - A Java Image object which uses the DirectColorModel

encodeAlpha - Encode the alpha channel? false=no; true=yes

See Also:

Image

PngEncoder

public PngEncoder(java.awt.Image image,
                  boolean encodeAlpha,
                  int whichFilter)

Class constructor specifying Image to encode, whether to encode alpha, and filter to use.

Parameters:

image - A Java Image object which uses the DirectColorModel

encodeAlpha - Encode the alpha channel? false=no; true=yes

whichFilter - 0=none, 1=sub, 2=up

See Also:

Image

PngEncoder

public PngEncoder(java.awt.Image image,
                  boolean encodeAlpha,
                  int whichFilter,
                  int compLevel)

Class constructor specifying Image source to encode, whether to encode alpha, filter to use, and compression level.

Parameters:

image - A Java Image object

encodeAlpha - Encode the alpha channel? false=no; true=yes

whichFilter - 0=none, 1=sub, 2=up

compLevel - 0..9

See Also:

Image

Method Detail

setImage

public void setImage(java.awt.Image image)

Set the image to be encoded

Parameters:

image - A Java Image object which uses the DirectColorModel

See Also:

Image, DirectColorModel

pngEncode

public byte[] pngEncode(boolean encodeAlpha)

Creates an array of bytes that is the PNG equivalent of the current image, specifying whether to encode alpha or not.

Parameters:

encodeAlpha - boolean false=no alpha, true=encode alpha

Returns:

an array of bytes, or null if there was a problem

pngEncode

public byte[] pngEncode()

Creates an array of bytes that is the PNG equivalent of the current image. Alpha encoding is determined by its setting in the constructor.

Returns:

an array of bytes, or null if there was a problem

setEncodeAlpha

public void setEncodeAlpha(boolean encodeAlpha)

Set the alpha encoding on or off.

Parameters:

encodeAlpha - false=no, true=yes

getEncodeAlpha

public boolean getEncodeAlpha()

Retrieve alpha encoding status.

Returns:

boolean false=no, true=yes

setFilter

public void setFilter(int whichFilter)

Set the filter to use

Parameters:

whichFilter - from constant list

getFilter

public int getFilter()

Retrieve filtering scheme

Returns:

int (see constant list)

setCompressionLevel

public void setCompressionLevel(int level)

Set the compression level to use

Parameters:

level - 0 through 9

getCompressionLevel

public int getCompressionLevel()

Retrieve compression level

Returns:

int in range 0-9