Module java.desktop

Package javax.imageio.plugins.tiff

Class TIFFTag

java.lang.Object

javax.imageio.plugins.tiff.TIFFTag

public class TIFFTag
extends Object

A class defining the notion of a TIFF tag. A TIFF tag is a key that may appear in an Image File Directory (IFD). In the IFD each tag has some data associated with it, which may consist of zero or more values of a given data type. The combination of a tag and a value is known as an IFD Entry or TIFF Field.

The actual tag values used in the root IFD of a standard ("baseline") tiff stream are defined in the BaselineTIFFTagSet class.

Since:

9

See Also:

• BaselineTIFFTagSet
• TIFFField
• TIFFTagSet

Field Summary

Fields

Modifier and Type	Field	Description
static final int	MAX_DATATYPE	The numerically largest constant representing a TIFF data type.
static final int	MIN_DATATYPE	The numerically smallest constant representing a TIFF data type.
static final int	TIFF_ASCII	Flag for null-terminated ASCII strings.
static final int	TIFF_BYTE	Flag for 8 bit unsigned integers.
static final int	TIFF_DOUBLE	Flag for 64 bit IEEE doubles.
static final int	TIFF_FLOAT	Flag for 32 bit IEEE floats.
static final int	TIFF_IFD_POINTER	Flag for IFD pointer defined in TIFF Tech Note 1 in TIFF Specification Supplement 1.
static final int	TIFF_LONG	Flag for 32 bit unsigned integers.
static final int	TIFF_RATIONAL	Flag for pairs of 32 bit unsigned integers.
static final int	TIFF_SBYTE	Flag for 8 bit signed integers.
static final int	TIFF_SHORT	Flag for 16 bit unsigned integers.
static final int	TIFF_SLONG	Flag for 32 bit signed integers.
static final int	TIFF_SRATIONAL	Flag for pairs of 32 bit signed integers.
static final int	TIFF_SSHORT	Flag for 16 bit signed integers.
static final int	TIFF_UNDEFINED	Flag for 8 bit uninterpreted bytes.
static final String	UNKNOWN_TAG_NAME	The name assigned to a tag with an unknown tag number.

Constructor Summary

Constructors

Constructor	Description
TIFFTag(String name, int number, int dataTypes)	Constructs a TIFFTag with a given name, tag number, and set of legal data types.
TIFFTag(String name, int number, int dataTypes, int count)	Constructs a TIFFTag with a given name, tag number, set of legal data types, and value count.
TIFFTag(String name, int number, TIFFTagSet tagSet)	Constructs a TIFFTag with a given name, tag number and TIFFTagSet to which it refers.

Method Summary

Modifier and Type	Method	Description
protected void	addValueName(int value, String name)	Adds a mnemonic name for a particular value that this tag's data may take on.
int	getCount()	Returns the value count of this tag.
int	getDataTypes()	Returns a bit mask indicating the set of data types that may be used to store the data associated with the tag.
String	getName()	Returns the name of the tag, as it will appear in image metadata.
int[]	getNamedValues()	Returns an array of values for which mnemonic names are defined.
int	getNumber()	Returns the integer used to represent the tag.
static int	getSizeOfType(int dataType)	Returns the number of bytes used to store a value of the given data type.
TIFFTagSet	getTagSet()	Returns the TIFFTagSet of which this tag is a part.
String	getValueName(int value)	Returns the mnemonic name associated with a particular value that this tag's data may take on, or null if no name is present.
boolean	hasValueNames()	Returns true if there are mnemonic names associated with the set of legal values for the data associated with this tag.
boolean	isDataTypeOK(int dataType)	Returns true if the given data type may be used for the data associated with this tag.
boolean	isIFDPointer()	Returns true if this tag is used to point to an IFD structure containing additional tags.

Methods declared in class java.lang.Object

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

Field Details

TIFF_BYTE

public static final int TIFF_BYTE

Flag for 8 bit unsigned integers.

See Also:

• Constant Field Values

TIFF_ASCII

public static final int TIFF_ASCII

Flag for null-terminated ASCII strings.

See Also:

• Constant Field Values

TIFF_SHORT

public static final int TIFF_SHORT

Flag for 16 bit unsigned integers.

See Also:

• Constant Field Values

TIFF_LONG

public static final int TIFF_LONG

Flag for 32 bit unsigned integers.

See Also:

• Constant Field Values

TIFF_RATIONAL

public static final int TIFF_RATIONAL

Flag for pairs of 32 bit unsigned integers.

See Also:

• Constant Field Values

TIFF_SBYTE

public static final int TIFF_SBYTE

Flag for 8 bit signed integers.

See Also:

• Constant Field Values

TIFF_UNDEFINED

public static final int TIFF_UNDEFINED

Flag for 8 bit uninterpreted bytes.

See Also:

• Constant Field Values

TIFF_SSHORT

public static final int TIFF_SSHORT

Flag for 16 bit signed integers.

See Also:

• Constant Field Values

TIFF_SLONG

public static final int TIFF_SLONG

Flag for 32 bit signed integers.

See Also:

• Constant Field Values

TIFF_SRATIONAL

public static final int TIFF_SRATIONAL

Flag for pairs of 32 bit signed integers.

See Also:

• Constant Field Values

TIFF_FLOAT

public static final int TIFF_FLOAT

Flag for 32 bit IEEE floats.

See Also:

• Constant Field Values

TIFF_DOUBLE

public static final int TIFF_DOUBLE

Flag for 64 bit IEEE doubles.

See Also:

• Constant Field Values

TIFF_IFD_POINTER

public static final int TIFF_IFD_POINTER

Flag for IFD pointer defined in TIFF Tech Note 1 in TIFF Specification Supplement 1.

See Also:

• Constant Field Values

MIN_DATATYPE

public static final int MIN_DATATYPE

The numerically smallest constant representing a TIFF data type.

See Also:

• Constant Field Values

MAX_DATATYPE

public static final int MAX_DATATYPE

The numerically largest constant representing a TIFF data type.

See Also:

• Constant Field Values

UNKNOWN_TAG_NAME

public static final String UNKNOWN_TAG_NAME

The name assigned to a tag with an unknown tag number. Such a tag may be created for example when reading an IFD and a tag number is encountered which is not in any of the TIFFTagSets known to the reader.

See Also:

• Constant Field Values

Constructor Details

TIFFTag

public TIFFTag(String name,
 int number,
 int dataTypes,
 int count)

Constructs a TIFFTag with a given name, tag number, set of legal data types, and value count. A negative value count signifies that either an arbitrary number of values is legal or the required count is determined by the values of other fields in the IFD. A non-negative count specifies the number of values which an associated field must contain. The tag will have no associated TIFFTagSet.

If there are mnemonic names to be associated with the legal data values for the tag, addValueName() should be called on the new instance for each name. Mnemonic names apply only to tags which have integral data type.

See the documentation for getDataTypes() for an explanation of how the set of data types is to be converted into a bit mask.

Parameters:

name - the name of the tag.

number - the number used to represent the tag.

dataTypes - a bit mask indicating the set of legal data types for this tag.

count - the value count for this tag.

Throws:

NullPointerException - if name is null.

IllegalArgumentException - if number is negative or dataTypes is negative or specifies an out of range type.

TIFFTag

public TIFFTag(String name,
 int number,
 TIFFTagSet tagSet)

Constructs a TIFFTag with a given name, tag number and TIFFTagSet to which it refers. The legal data types are set to include TIFF_LONG and TIFF_IFD_POINTER and the value count is unity. The TIFFTagSet will represent the set of TIFFTags which appear in the IFD pointed to. A TIFFTag represents an IFD pointer if and only if tagSet is non-null or the data type TIFF_IFD_POINTER is legal.

Parameters:

name - the name of the tag.

number - the number used to represent the tag.

tagSet - the TIFFTagSet to which this tag belongs.

Throws:

NullPointerException - if name or tagSet is null.

IllegalArgumentException - if number is negative.

See Also:

• TIFFTag(String, int, int, int)

TIFFTag

public TIFFTag(String name,
 int number,
 int dataTypes)

Constructs a TIFFTag with a given name, tag number, and set of legal data types. The value count of the tag will be undefined and it will have no associated TIFFTagSet.

Parameters:

name - the name of the tag.

number - the number used to represent the tag.

dataTypes - a bit mask indicating the set of legal data types for this tag.

Throws:

NullPointerException - if name is null.

IllegalArgumentException - if number is negative or dataTypes is negative or specifies an out of range type.

See Also:

• TIFFTag(String, int, int, int)

Method Details

getSizeOfType

public static int getSizeOfType(int dataType)

Returns the number of bytes used to store a value of the given data type.

Parameters:

dataType - the data type to be queried.

Returns:

the number of bytes used to store the given data type.

Throws:

IllegalArgumentException - if datatype is less than MIN_DATATYPE or greater than MAX_DATATYPE.

getName

public String getName()

Returns the name of the tag, as it will appear in image metadata.

Returns:

the tag name, as a String.

getNumber

public int getNumber()

Returns the integer used to represent the tag.

Returns:

the tag number, as an int.

getDataTypes

public int getDataTypes()

Returns a bit mask indicating the set of data types that may be used to store the data associated with the tag. For example, a tag that can store both SHORT and LONG values would return a value of:

 (1 << TIFFTag.TIFF_SHORT) | (1 << TIFFTag.TIFF_LONG)
 

Returns:

an int containing a bitmask encoding the set of valid data types.

getCount

public int getCount()

Returns the value count of this tag. If this value is positive, it represents the required number of values for a TIFFField which has this tag. If the value is negative, the count is undefined. In the latter case the count may be derived, e.g., the number of values of the BitsPerSample field is SamplesPerPixel, or it may be variable as in the case of most US-ASCII fields.

Returns:

the value count of this tag.

isDataTypeOK

public boolean isDataTypeOK(int dataType)

Returns true if the given data type may be used for the data associated with this tag.

Parameters:

dataType - the data type to be queried, one of TIFF_BYTE, TIFF_SHORT, etc.

Returns:

a boolean indicating whether the given data type may be used with this tag.

Throws:

IllegalArgumentException - if datatype is less than MIN_DATATYPE or greater than MAX_DATATYPE.

getTagSet

public TIFFTagSet getTagSet()

Returns the TIFFTagSet of which this tag is a part.

Returns:

the containing TIFFTagSet.

isIFDPointer

public boolean isIFDPointer()

Returns true if this tag is used to point to an IFD structure containing additional tags. A TIFFTag represents an IFD pointer if and only if its TIFFTagSet is non-null or the data type TIFF_IFD_POINTER is legal. This condition will be satisfied if and only if either getTagSet() != null or isDataTypeOK(TIFF_IFD_POINTER) == true.

Many TIFF extensions use the IFD mechanism in order to limit the number of new tags that may appear in the root IFD.

Returns:

true if this tag points to an IFD.

hasValueNames

public boolean hasValueNames()

Returns true if there are mnemonic names associated with the set of legal values for the data associated with this tag. Mnemonic names apply only to tags which have integral data type.

Returns:

true if mnemonic value names are available.

addValueName

protected void addValueName(int value,
 String name)

Adds a mnemonic name for a particular value that this tag's data may take on. Mnemonic names apply only to tags which have integral data type.

Parameters:

value - the data value.

name - the name to associate with the value.

getValueName

public String getValueName(int value)

Returns the mnemonic name associated with a particular value that this tag's data may take on, or null if no name is present. Mnemonic names apply only to tags which have integral data type.

Parameters:

value - the data value.

Returns:

the mnemonic name associated with the value, as a String.

getNamedValues

public int[] getNamedValues()

Returns an array of values for which mnemonic names are defined. The method getValueName() will return non-null only for values contained in the returned array. Mnemonic names apply only to tags which have integral data type.

Returns:

the values for which there is a mnemonic name.