Package 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 https://drewnoakes.com

Field Summary

Fields

Modifier and Type	Field	Description
static final int	TAG_COMPONENT_DATA_1	the first of a possible 4 color components.
static final int	TAG_COMPONENT_DATA_2	the second of a possible 4 color components.
static final int	TAG_COMPONENT_DATA_3	the third of a possible 4 color components.
static final int	TAG_COMPONENT_DATA_4	the fourth of a possible 4 color components.
static final int	TAG_COMPRESSION_TYPE
static final int	TAG_DATA_PRECISION	This is in bits/sample, usually 8 (12 and 16 not supported by most software).
static final int	TAG_IMAGE_HEIGHT	The image's height.
static final int	TAG_IMAGE_WIDTH	The image's width.
static final int	TAG_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).

Constructor Summary

Constructors

Constructor	Description
JpegDirectory()

Method Summary

Modifier and Type	Method	Description
JpegComponent	getComponent(int componentNumber)
int	getImageHeight()
int	getImageWidth()
String	getName()	Provides the name of the directory, for display purposes.
int	getNumberOfComponents()

Methods inherited from class com.drew.metadata.Directory

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

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

TAG_COMPRESSION_TYPE

public static final int TAG_COMPRESSION_TYPE

See Also:

• Constant Field Values

TAG_DATA_PRECISION

public static final int TAG_DATA_PRECISION

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

See Also:

• Constant Field Values

TAG_IMAGE_HEIGHT

public static final int TAG_IMAGE_HEIGHT

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

See Also:

• Constant Field Values

TAG_IMAGE_WIDTH

public static final int TAG_IMAGE_WIDTH

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

See Also:

• Constant Field Values

TAG_NUMBER_OF_COMPONENTS

public static final int TAG_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_COMPONENT_DATA_1

public static final int TAG_COMPONENT_DATA_1

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

See Also:

• Constant Field Values

TAG_COMPONENT_DATA_2

public static final int TAG_COMPONENT_DATA_2

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

See Also:

• Constant Field Values

TAG_COMPONENT_DATA_3

public static final int TAG_COMPONENT_DATA_3

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

See Also:

• Constant Field Values

TAG_COMPONENT_DATA_4

public static final int TAG_COMPONENT_DATA_4

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

See Also:

• Constant Field Values

Constructor Details

JpegDirectory

public JpegDirectory()

Method Details

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

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