com.drew.metadata.jpeg
Class JpegDirectory

java.lang.Object
  com.drew.metadata.Directory
      com.drew.metadata.jpeg.JpegDirectory

public class JpegDirectory
extends Directory

Directory of tags and values for the SOF0 Jpeg segment. This segment holds basic metadata about the image.

Author:

Darrell Silver http://www.darrellsilver.com and Drew Noakes http://drewnoakes.com

Field Summary

protected static HashMap<Integer,String>	_tagNameMap
static int	TAG_JPEG_COMPONENT_DATA_1 the first of a possible 4 color components.
static int	TAG_JPEG_COMPONENT_DATA_2 the second of a possible 4 color components.
static int	TAG_JPEG_COMPONENT_DATA_3 the third of a possible 4 color components.
static int	TAG_JPEG_COMPONENT_DATA_4 the fourth of a possible 4 color components.
static int	TAG_JPEG_COMPRESSION_TYPE
static int	TAG_JPEG_DATA_PRECISION This is in bits/sample, usually 8 (12 and 16 not supported by most software).
static int	TAG_JPEG_IMAGE_HEIGHT The image's height.
static int	TAG_JPEG_IMAGE_WIDTH The image's width.
static int	TAG_JPEG_NUMBER_OF_COMPONENTS Usually 1 = grey scaled, 3 = color YcbCr or YIQ, 4 = color CMYK Each component TAG_COMPONENT_DATA_[1-4], has the following meaning: component Id(1byte)(1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q), sampling factors (1byte) (bit 0-3 vertical., 4-7 horizontal.), quantization table number (1 byte).

Fields inherited from class com.drew.metadata.Directory

_definedTagList, _descriptor, _tagMap

Constructor Summary

JpegDirectory()

Method Summary

JpegComponent	getComponent(int componentNumber)
int	getImageHeight()
int	getImageWidth()
String	getName() Provides the name of the directory, for display purposes.
int	getNumberOfComponents()
protected HashMap<Integer,String>	getTagNameMap() Provides the map of tag names, hashed by tag type identifier.

Methods inherited from class com.drew.metadata.Directory

addError, containsTag, getBoolean, getBooleanObject, getByteArray, getDate, getDate, getDescription, getDouble, getDoubleObject, getErrorCount, getErrors, getFloat, getFloatObject, getInt, getIntArray, getInteger, getLong, getLongObject, getObject, getRational, getRationalArray, getString, getString, getStringArray, getTagCount, getTagName, getTags, hasErrors, setBoolean, setByteArray, setDate, setDescriptor, setDouble, setDoubleArray, setFloat, setFloatArray, setInt, setIntArray, setLong, setObject, setObjectArray, setRational, setRationalArray, setString, setStringArray

Methods inherited from class java.lang.Object

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

Field Detail

TAG_JPEG_COMPRESSION_TYPE

public static final int TAG_JPEG_COMPRESSION_TYPE

See Also:

Constant Field Values

TAG_JPEG_DATA_PRECISION

public static final int TAG_JPEG_DATA_PRECISION

This is in bits/sample, usually 8 (12 and 16 not supported by most software).

See Also:

Constant Field Values

TAG_JPEG_IMAGE_HEIGHT

public static final int TAG_JPEG_IMAGE_HEIGHT

The image's height. Necessary for decoding the image, so it should always be there.

See Also:

Constant Field Values

TAG_JPEG_IMAGE_WIDTH

public static final int TAG_JPEG_IMAGE_WIDTH

The image's width. Necessary for decoding the image, so it should always be there.

See Also:

Constant Field Values

TAG_JPEG_NUMBER_OF_COMPONENTS

public static final int TAG_JPEG_NUMBER_OF_COMPONENTS

Usually 1 = grey scaled, 3 = color YcbCr or YIQ, 4 = color CMYK Each component TAG_COMPONENT_DATA_[1-4], has the following meaning: component Id(1byte)(1 = Y, 2 = Cb, 3 = Cr, 4 = I, 5 = Q), sampling factors (1byte) (bit 0-3 vertical., 4-7 horizontal.), quantization table number (1 byte).

This info is from http://www.funducode.com/freec/Fileformats/format3/format3b.htm

See Also:

Constant Field Values

TAG_JPEG_COMPONENT_DATA_1

public static final int TAG_JPEG_COMPONENT_DATA_1

the first of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS.

See Also:

Constant Field Values

TAG_JPEG_COMPONENT_DATA_2

public static final int TAG_JPEG_COMPONENT_DATA_2

the second of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS.

See Also:

Constant Field Values

TAG_JPEG_COMPONENT_DATA_3

public static final int TAG_JPEG_COMPONENT_DATA_3

the third of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS.

See Also:

Constant Field Values

TAG_JPEG_COMPONENT_DATA_4

public static final int TAG_JPEG_COMPONENT_DATA_4

the fourth of a possible 4 color components. Number of components specified in TAG_JPEG_NUMBER_OF_COMPONENTS.

See Also:

Constant Field Values

_tagNameMap

protected static final HashMap<Integer,String> _tagNameMap

Constructor Detail

JpegDirectory

public JpegDirectory()

Method Detail

getName

public String getName()

Description copied from class: Directory

Provides the name of the directory, for display purposes. E.g. Exif

Specified by:

getName in class Directory

Returns:

the name of the directory

getTagNameMap

protected HashMap<Integer,String> getTagNameMap()

Description copied from class: Directory

Provides the map of tag names, hashed by tag type identifier.

Specified by:

getTagNameMap in class Directory

Returns:

the map of tag names

getComponent

public JpegComponent getComponent(int componentNumber)

Parameters:

componentNumber - The zero-based index of the component. This number is normally between 0 and 3. Use getNumberOfComponents for bounds-checking.

Returns:

the JpegComponent having the specified number.

getImageWidth

public int getImageWidth()
                  throws MetadataException

Throws:

MetadataException

getImageHeight

public int getImageHeight()
                   throws MetadataException

Throws:

MetadataException

getNumberOfComponents

public int getNumberOfComponents()
                          throws MetadataException

Throws:

MetadataException