Package bdsup2sub.tools

Class EnhancedPngEncoder

java.lang.Object

bdsup2sub.tools.PngEncoder

bdsup2sub.tools.EnhancedPngEncoder

public class EnhancedPngEncoder
extends PngEncoder

Version:

1.5, 19 Oct 2003 (modified by 0xdeadbeef in 2009 and mjuhasz in 2012) CHANGES:
--------
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
Added modifications for unsigned short images
(contributed by Christian at xpogen.com)
10-Nov-2012 : Removed unused constants and useless method override. (mjuhasz)

Field Summary

Fields

Modifier and Type	Field	Description
private BufferedImage	image
private static final byte[]	PLTE	PLTE tag.
private static final byte[]	TRNS	tRNS tag.
private int	tType
private WritableRaster	wRaster

Fields inherited from class bdsup2sub.tools.PngEncoder

bytePos, bytesPerPixel, compressionLevel, crc, crcValue, encodeAlpha, filter, FILTER_LAST, FILTER_NONE, FILTER_SUB, FILTER_UP, height, IDAT, IEND, IHDR, leftBytes, maxPos, pngBytes, priorRow, width

Constructor Summary

Constructors

Modifier	Constructor	Description
	EnhancedPngEncoder()
	EnhancedPngEncoder(BufferedImage image)	Class constructor specifying BufferedImage to encode, with no alpha channel encoding.
	EnhancedPngEncoder(BufferedImage image, boolean encodeAlpha)	Class constructor specifying BufferedImage to encode, and whether to encode alpha.
	EnhancedPngEncoder(BufferedImage image, boolean encodeAlpha, int whichFilter)	Class constructor specifying BufferedImage to encode, whether to encode alpha, and filter to use.
private	EnhancedPngEncoder(BufferedImage image, boolean encodeAlpha, int whichFilter, int compLevel)	Class constructor specifying BufferedImage source to encode, whether to encode alpha, filter to use, and compression level.

Method Summary

Modifier and Type	Method	Description
(package private) boolean	establishStorageInfo()	Get and set variables that determine how picture is stored.
byte[]	pngEncode()	Creates an array of bytes that is the PNG equivalent of the current image.
void	setImage(BufferedImage image)	Set the BufferedImage to be encoded.
(package private) void	writeAlpha(IndexColorModel icm)
protected void	writeHeader()	Write a PNG "IHDR" chunk into the pngBytes array.
protected boolean	writeImageData()	Write the image data into the pngBytes array.
(package private) void	writePalette(IndexColorModel icm)

Methods inherited from class bdsup2sub.tools.PngEncoder

filterSub, filterUp, getCompressionLevel, getEncodeAlpha, getFilter, resizeByteArray, setCompressionLevel, setEncodeAlpha, setFilter, setImage, writeByte, writeBytes, writeBytes, writeEnd, writeInt2, writeInt4

Methods inherited from class java.lang.Object

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

Field Details

PLTE

private static final byte[] PLTE

PLTE tag.

TRNS

private static final byte[] TRNS

tRNS tag.

image

private BufferedImage image

wRaster

private WritableRaster wRaster

tType

private int tType

Constructor Details

EnhancedPngEncoder

public EnhancedPngEncoder()

EnhancedPngEncoder

public EnhancedPngEncoder(BufferedImage image)

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

Parameters:

image - A Java BufferedImage object

EnhancedPngEncoder

public EnhancedPngEncoder(BufferedImage image,
 boolean encodeAlpha)

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

Parameters:

image - A Java BufferedImage object

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

EnhancedPngEncoder

public EnhancedPngEncoder(BufferedImage image,
 boolean encodeAlpha,
 int whichFilter)

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

Parameters:

image - A Java BufferedImage object

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

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

EnhancedPngEncoder

private EnhancedPngEncoder(BufferedImage image,
 boolean encodeAlpha,
 int whichFilter,
 int compLevel)

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

Parameters:

image - A Java BufferedImage object

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

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

compLevel - 0..9

Method Details

setImage

public void setImage(BufferedImage image)

Set the BufferedImage to be encoded.

Parameters:

image - A Java BufferedImage object

pngEncode

public byte[] pngEncode()

Creates an array of bytes that is the PNG equivalent of the current image.

Overrides:

pngEncode in class PngEncoder

Returns:

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

establishStorageInfo

boolean establishStorageInfo()

Get and set variables that determine how picture is stored. Retrieves the writable raster of the buffered image, as well its transfer type. Sets number of output bytes per pixel, and, if only eight-bit bytes, turns off alpha encoding.

Returns:

true if 1-byte or 4-byte data, false otherwise

writeHeader

protected void writeHeader()

Write a PNG "IHDR" chunk into the pngBytes array.

Overrides:

writeHeader in class PngEncoder

writePalette

void writePalette(IndexColorModel icm)

writeAlpha

void writeAlpha(IndexColorModel icm)

writeImageData

protected boolean writeImageData()

Write the image data into the pngBytes array. This will write one or more PNG "IDAT" chunks. In order to conserve memory, this method grabs as many rows as will fit into 32K bytes, or the whole image; whichever is less.

Overrides:

writeImageData in class PngEncoder

Returns:

true if no errors; false if error grabbing pixels