com.drew.imaging.png

Class PngChunkType

java.lang.Object

com.drew.imaging.png.PngChunkType

public class PngChunkType
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
private byte[]	_bytes
private static java.util.Set<java.lang.String>	_identifiersAllowingMultiples
private boolean	_multipleAllowed
static PngChunkType	bKGD
static PngChunkType	cHRM
static PngChunkType	gAMA
static PngChunkType	hIST
static PngChunkType	iCCP
static PngChunkType	IDAT
static PngChunkType	IEND
static PngChunkType	IHDR Denotes a critical PngChunk that contains basic information about the PNG image.
static PngChunkType	iTXt
static PngChunkType	pHYs
static PngChunkType	PLTE Denotes a critical PngChunk that contains palette entries.
static PngChunkType	sBIT
static PngChunkType	sPLT
static PngChunkType	sRGB
static PngChunkType	tEXt Denotes an ancillary PngChunk that contains textual data, having first a keyword and then a value.
static PngChunkType	tIME
static PngChunkType	tRNS
static PngChunkType	zTXt

Constructor Summary

Constructors

Constructor and Description
PngChunkType(byte[] bytes)
PngChunkType(java.lang.String identifier)
PngChunkType(java.lang.String identifier, boolean multipleAllowed)

Method Summary

Modifier and Type	Method and Description
boolean	areMultipleAllowed()
boolean	equals(java.lang.Object o)
java.lang.String	getIdentifier()
int	hashCode()
boolean	isAncillary()
boolean	isCritical()
private static boolean	isLowerCase(byte b)
boolean	isPrivate()
boolean	isSafeToCopy()
private static boolean	isUpperCase(byte b)
private static boolean	isValidByte(byte b)
java.lang.String	toString()
private static void	validateBytes(byte[] bytes)

Methods inherited from class java.lang.Object

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

Field Detail

_identifiersAllowingMultiples

private static final java.util.Set<java.lang.String> _identifiersAllowingMultiples

IHDR

public static final PngChunkType IHDR

Denotes a critical PngChunk that contains basic information about the PNG image. This must be the first chunk in the data sequence, and may only occur once.

The format is:

• pixel width 4 bytes, unsigned and greater than zero
• pixel height 4 bytes, unsigned and greater than zero
• bit depth 1 byte, number of bits per sample or per palette index (not per pixel)
• color type 1 byte, maps to PngColorType enum
• compression method 1 byte, currently only a value of zero (deflate/inflate) is in the standard
• filter method 1 byte, currently only a value of zero (adaptive filtering with five basic filter types) is in the standard
• interlace method 1 byte, indicates the transmission order of image data, currently only 0 (no interlace) and 1 (Adam7 interlace) are in the standard

PLTE

public static final PngChunkType PLTE

Denotes a critical PngChunk that contains palette entries. This chunk should only appear for a PngColorType of IndexedColor, and may only occur once in the PNG data sequence.

The chunk contains between one and 256 entries, each of three bytes:

• red 1 byte
• green 1 byte
• blue 1 byte

The number of entries is determined by the chunk length. A chunk length indivisible by three is an error.

IDAT

public static final PngChunkType IDAT

IEND

public static final PngChunkType IEND

cHRM

public static final PngChunkType cHRM

gAMA

public static final PngChunkType gAMA

iCCP

public static final PngChunkType iCCP

sBIT

public static final PngChunkType sBIT

sRGB

public static final PngChunkType sRGB

bKGD

public static final PngChunkType bKGD

hIST

public static final PngChunkType hIST

tRNS

public static final PngChunkType tRNS

pHYs

public static final PngChunkType pHYs

sPLT

public static final PngChunkType sPLT

tIME

public static final PngChunkType tIME

iTXt

public static final PngChunkType iTXt

tEXt

public static final PngChunkType tEXt

Denotes an ancillary PngChunk that contains textual data, having first a keyword and then a value. If multiple text data keywords are needed, then multiple chunks are included in the PNG data stream.

The format is:

• keyword 1-79 bytes
• null separator 1 byte (\0)
• text string 0 or more bytes

Text is interpreted according to the Latin-1 character set [ISO-8859-1]. Newlines should be represented by a single linefeed character (0x9).

zTXt

public static final PngChunkType zTXt

_bytes

private final byte[] _bytes

_multipleAllowed

private final boolean _multipleAllowed

Constructor Detail

PngChunkType

public PngChunkType(java.lang.String identifier)
             throws PngProcessingException

Throws:

PngProcessingException

PngChunkType

public PngChunkType(java.lang.String identifier,
                    boolean multipleAllowed)
             throws PngProcessingException

Throws:

PngProcessingException

PngChunkType

public PngChunkType(byte[] bytes)
             throws PngProcessingException

Throws:

PngProcessingException

Method Detail

validateBytes

private static void validateBytes(byte[] bytes)
                           throws PngProcessingException

Throws:

PngProcessingException

isCritical

public boolean isCritical()

isAncillary

public boolean isAncillary()

isPrivate

public boolean isPrivate()

isSafeToCopy

public boolean isSafeToCopy()

areMultipleAllowed

public boolean areMultipleAllowed()

isLowerCase

private static boolean isLowerCase(byte b)

isUpperCase

private static boolean isUpperCase(byte b)

isValidByte

private static boolean isValidByte(byte b)

getIdentifier

public java.lang.String getIdentifier()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object