deadbeef.Tools
Class PngEncoder

java.lang.Object
  extended by deadbeef.Tools.PngEncoder
Direct Known Subclasses:
PngEncoderB

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

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA A copy of the GNU LGPL may be found at http://www.gnu.org/copyleft/lesser.html

Version:
1.5, 19 Oct 2003 CHANGES:
--------
19-Nov-2002 : CODING STYLE CHANGES ONLY (by David Gilbert for Object Refinery Limited);
19-Sep-2003 : Fix for platforms using EBCDIC (contributed by Paulo Soares);
19-Oct-2003 : Change private fields to protected fields so that
PngEncoderB can inherit them (JDE)
Fixed bug with calculation of nRows
Author:
J. David Eisenberg

Field Summary
static boolean ENCODE_ALPHA
          Constant specifying that alpha channel should be encoded.
static int FILTER_LAST
          Constants for filter (LAST)
static int FILTER_NONE
          Constants for filter (NONE)
static int FILTER_SUB
          Constants for filter (SUB)
static int FILTER_UP
          Constants for 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 filter (NONE)

See Also:
Constant Field Values

FILTER_SUB

public static final int FILTER_SUB
Constants for filter (SUB)

See Also:
Constant Field Values

FILTER_UP

public static final int FILTER_UP
Constants for filter (UP)

See Also:
Constant Field Values

FILTER_LAST

public static final int FILTER_LAST
Constants for 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