Class GifImageParser

java.lang.Object

org.apache.commons.imaging.common.BinaryFileParser

org.apache.commons.imaging.AbstractImageParser<GifImagingParameters>

org.apache.commons.imaging.formats.gif.GifImageParser

All Implemented Interfaces:

XmpEmbeddable<GifImagingParameters>

public class GifImageParser
extends AbstractImageParser<GifImagingParameters>
implements XmpEmbeddable<GifImagingParameters>

Field Summary

Fields

Modifier and Type	Field	Description
private static final String[]	ACCEPTED_EXTENSIONS
private static final int	APPLICATION_EXTENSION_LABEL
private static final int	COMMENT_EXTENSION
private static final String	DEFAULT_EXTENSION
private static final int	EXTENSION_CODE
private static final byte[]	GIF_HEADER_SIGNATURE
private static final int	GRAPHIC_CONTROL_EXTENSION
private static final int	IMAGE_SEPARATOR
private static final int	INTERLACE_FLAG_MASK
private static final int	LOCAL_COLOR_TABLE_FLAG_MASK
private static final Logger	LOGGER
private static final int	PLAIN_TEXT_EXTENSION
private static final int	SORT_FLAG_MASK
private static final int	TERMINATOR_BYTE
private static final byte[]	XMP_APPLICATION_ID_AND_AUTH_CODE
private static final int	XMP_COMPLETE_CODE
private static final int	XMP_EXTENSION

Constructor Summary

Constructors

Constructor	Description
GifImageParser()	Constructs a new instance with the little-endian byte order.

Method Summary

Modifier and Type	Method	Description
private int	convertColorTableSize(int tableSize)
(package private) static DisposalMethod	createDisposalMethodFromIntValue(int value)
boolean	dumpImageFile(PrintWriter pw, ByteSource byteSource)	Writes the ImageInfo and format-specific information for the image content of the specified byte source to a PrintWriter
private <T extends GifBlock> List<T>	findAllBlocks(List<GifBlock> blocks, int code)	See readBlocks(GifHeaderInfo, InputStream, boolean, FormatCompliance) for reference how the blocks are created.
private List<GifImageData>	findAllImageData(GifImageContents imageContents)
private GifBlock	findBlock(List<GifBlock> blocks, int code)
private GifImageData	findFirstImageData(GifImageContents imageContents)
protected String[]	getAcceptedExtensions()	Gets an array of all accepted extensions
protected ImageFormat[]	getAcceptedTypes()	Gets an array of ImageFormat objects describing all accepted types
List<BufferedImage>	getAllBufferedImages(ByteSource byteSource)	Gets all images specified by the byte source (some formats may include multiple images within a single data source).
BufferedImage	getBufferedImage(ByteSource byteSource, GifImagingParameters params)	Gets a buffered image specified by the byte source (for sources that specify multiple images, choice of which image is returned is implementation dependent).
private BufferedImage	getBufferedImage(GifImageData imageData, byte[] globalColorTable)
private int[]	getColorTable(byte[] bytes)
private List<String>	getComments(List<GifBlock> blocks)
String	getDefaultExtension()	Gets the default extension for the format specified by an implementation of ImageParser.
GifImagingParameters	getDefaultParameters()	Gets a default parameters instance for this parser.
FormatCompliance	getFormatCompliance(ByteSource byteSource)	Determines the format compliance of the content of the supplied byte source based on rules provided by a specific implementation.
byte[]	getIccProfileBytes(ByteSource byteSource, GifImagingParameters params)	Gets an array of bytes describing the International Color Consortium (ICC) specification for the color space of the image contained in the input byteSource.
ImageInfo	getImageInfo(ByteSource byteSource, GifImagingParameters params)	Gets image information from the specified ByteSource.
Dimension	getImageSize(ByteSource byteSource, GifImagingParameters params)	Gets the size of the image described by the specified ByteSource.
ImageMetadata	getMetadata(ByteSource byteSource, GifImagingParameters params)	Gets image metadata from the specified byte source.
String	getName()	Gets a descriptive name for the implementation of an ImageParser.
String	getXmpXml(ByteSource byteSource, XmpImagingParameters<GifImagingParameters> params)	Extracts embedded XML metadata as XML string.
private List<GifBlock>	readBlocks(GifHeaderInfo ghi, InputStream is, boolean stopBeforeImageData, FormatCompliance formatCompliance)
private byte[]	readColorTable(InputStream is, int tableSize)
private GifImageContents	readFile(ByteSource byteSource, boolean stopBeforeImageData)
private GifImageContents	readFile(ByteSource byteSource, boolean stopBeforeImageData, FormatCompliance formatCompliance)
private GenericGifBlock	readGenericGifBlock(InputStream is, int code)
private GenericGifBlock	readGenericGifBlock(InputStream is, int code, byte[] first)
private GraphicControlExtension	readGraphicControlExtension(int code, InputStream is)
private GifHeaderInfo	readHeader(InputStream is, FormatCompliance formatCompliance)
private ImageDescriptor	readImageDescriptor(GifHeaderInfo ghi, int blockCode, InputStream is, boolean stopBeforeImageData, FormatCompliance formatCompliance)
private byte[]	readSubBlock(InputStream is)
private int	simplePow(int base, int power)
private void	writeAsSubBlocks(byte[] bytes, OutputStream os)
void	writeImage(BufferedImage src, OutputStream os, GifImagingParameters params)	Writes the content of a BufferedImage to the specified output stream.

Methods inherited from class AbstractImageParser

canAcceptExtension, canAcceptExtension, canAcceptType, dumpImageFile, dumpImageFile, dumpImageFile, getAllBufferedImages, getAllBufferedImages, getAllImageParsers, getBufferedImage, getBufferedImage, getBufferedImageFactory, getFormatCompliance, getFormatCompliance, getIccProfileBytes, getIccProfileBytes, getIccProfileBytes, getIccProfileBytes, getImageInfo, getImageInfo, getImageInfo, getImageSize, getImageSize, getImageSize, getImageSize, getMetadata, getMetadata, getMetadata, getMetadata, getMetadata

Methods inherited from class BinaryFileParser

debugNumber, debugNumber, getByteOrder, setByteOrder

Methods inherited from class Object

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

Field Details

LOGGER

private static final Logger LOGGER

DEFAULT_EXTENSION

private static final String DEFAULT_EXTENSION

ACCEPTED_EXTENSIONS

private static final String[] ACCEPTED_EXTENSIONS

GIF_HEADER_SIGNATURE

private static final byte[] GIF_HEADER_SIGNATURE

EXTENSION_CODE

private static final int EXTENSION_CODE

See Also:

• Constant Field Values

IMAGE_SEPARATOR

private static final int IMAGE_SEPARATOR

See Also:

• Constant Field Values

GRAPHIC_CONTROL_EXTENSION

private static final int GRAPHIC_CONTROL_EXTENSION

See Also:

• Constant Field Values

COMMENT_EXTENSION

private static final int COMMENT_EXTENSION

See Also:

• Constant Field Values

PLAIN_TEXT_EXTENSION

private static final int PLAIN_TEXT_EXTENSION

See Also:

• Constant Field Values

XMP_EXTENSION

private static final int XMP_EXTENSION

See Also:

• Constant Field Values

TERMINATOR_BYTE

private static final int TERMINATOR_BYTE

See Also:

• Constant Field Values

APPLICATION_EXTENSION_LABEL

private static final int APPLICATION_EXTENSION_LABEL

See Also:

• Constant Field Values

XMP_COMPLETE_CODE

private static final int XMP_COMPLETE_CODE

See Also:

• Constant Field Values

LOCAL_COLOR_TABLE_FLAG_MASK

private static final int LOCAL_COLOR_TABLE_FLAG_MASK

See Also:

• Constant Field Values

INTERLACE_FLAG_MASK

private static final int INTERLACE_FLAG_MASK

See Also:

• Constant Field Values

SORT_FLAG_MASK

private static final int SORT_FLAG_MASK

See Also:

• Constant Field Values

XMP_APPLICATION_ID_AND_AUTH_CODE

private static final byte[] XMP_APPLICATION_ID_AND_AUTH_CODE

Constructor Details

GifImageParser

public GifImageParser()

Constructs a new instance with the little-endian byte order.

Method Details

createDisposalMethodFromIntValue

static DisposalMethod createDisposalMethodFromIntValue(int value)
                                                throws ImagingException

Throws:

ImagingException

convertColorTableSize

private int convertColorTableSize(int tableSize)

dumpImageFile

public boolean dumpImageFile(PrintWriter pw,
 ByteSource byteSource)
                      throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Writes the ImageInfo and format-specific information for the image content of the specified byte source to a PrintWriter

Overrides:

dumpImageFile in class AbstractImageParser<GifImagingParameters>

Parameters:

pw - print writer used for writing the ImageInfo

byteSource - A valid byte source.

Returns:

A valid PrintWriter.

Throws:

ImagingException - In the event that the specified content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful read or access operation.

findAllBlocks

private <T extends GifBlock> List<T> findAllBlocks(List<GifBlock> blocks,
 int code)

See readBlocks(GifHeaderInfo, InputStream, boolean, FormatCompliance) for reference how the blocks are created. They should match the code we are giving here, returning the correct class type. Internal only.

findAllImageData

private List<GifImageData> findAllImageData(GifImageContents imageContents)
                                     throws ImagingException

Throws:

ImagingException

findBlock

private GifBlock findBlock(List<GifBlock> blocks,
 int code)

findFirstImageData

private GifImageData findFirstImageData(GifImageContents imageContents)
                                 throws ImagingException

Throws:

ImagingException

getAcceptedExtensions

protected String[] getAcceptedExtensions()

Description copied from class: AbstractImageParser

Gets an array of all accepted extensions

Specified by:

getAcceptedExtensions in class AbstractImageParser<GifImagingParameters>

Returns:

A valid array of one or more elements.

getAcceptedTypes

protected ImageFormat[] getAcceptedTypes()

Description copied from class: AbstractImageParser

Gets an array of ImageFormat objects describing all accepted types

Specified by:

getAcceptedTypes in class AbstractImageParser<GifImagingParameters>

Returns:

A valid array of one or more elements.

getAllBufferedImages

public List<BufferedImage> getAllBufferedImages(ByteSource byteSource)
                                         throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Gets all images specified by the byte source (some formats may include multiple images within a single data source).

Overrides:

getAllBufferedImages in class AbstractImageParser<GifImagingParameters>

Parameters:

byteSource - A valid instance of ByteSource.

Returns:

A valid (potentially empty) list of BufferedImage objects.

Throws:

ImagingException - In the event that the specified content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful read or access operation.

getBufferedImage

public BufferedImage getBufferedImage(ByteSource byteSource,
 GifImagingParameters params)
                               throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Gets a buffered image specified by the byte source (for sources that specify multiple images, choice of which image is returned is implementation dependent).

Specified by:

getBufferedImage in class AbstractImageParser<GifImagingParameters>

Parameters:

byteSource - A valid instance of ByteSource

params - Optional instructions for special-handling or interpretation of the input data (null objects are permitted and must be supported by implementations).

Returns:

A valid instance of BufferedImage.

Throws:

ImagingException - In the event that the specified content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful read or access operation.

getBufferedImage

private BufferedImage getBufferedImage(GifImageData imageData,
 byte[] globalColorTable)
                                throws ImagingException

Throws:

ImagingException

getColorTable

private int[] getColorTable(byte[] bytes)
                     throws ImagingException

Throws:

ImagingException

getComments

private List<String> getComments(List<GifBlock> blocks)
                          throws IOException

Throws:

IOException

getDefaultExtension

public String getDefaultExtension()

Description copied from class: AbstractImageParser

Gets the default extension for the format specified by an implementation of ImageParser. Some parsers can support more than one extension (i.e. .JPEG, .JPG; .TIF, .TIFF, etc.).

Specified by:

getDefaultExtension in class AbstractImageParser<GifImagingParameters>

Returns:

A valid string.

getDefaultParameters

public GifImagingParameters getDefaultParameters()

Description copied from class: AbstractImageParser

Gets a default parameters instance for this parser.

Specified by:

getDefaultParameters in class AbstractImageParser<GifImagingParameters>

Returns:

default parameters instance

getFormatCompliance

public FormatCompliance getFormatCompliance(ByteSource byteSource)
                                     throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Determines the format compliance of the content of the supplied byte source based on rules provided by a specific implementation.

Overrides:

getFormatCompliance in class AbstractImageParser<GifImagingParameters>

Parameters:

byteSource - A valid instance of ByteSource

Returns:

true if the content is format-compliant; otherwise, false

Throws:

ImagingException - may be thrown by sub-classes

IOException - may be thrown by sub-classes

getIccProfileBytes

public byte[] getIccProfileBytes(ByteSource byteSource,
 GifImagingParameters params)
                          throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Gets an array of bytes describing the International Color Consortium (ICC) specification for the color space of the image contained in the input byteSource. Not all formats support ICC profiles.

Specified by:

getIccProfileBytes in class AbstractImageParser<GifImagingParameters>

Parameters:

byteSource - A valid ByteSource.

params - Optional instructions for special-handling or interpretation of the input data.

Returns:

If available, a valid array of bytes; otherwise, a null

Throws:

ImagingException - In the event that the specified content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful read or access operation.

getImageInfo

public ImageInfo getImageInfo(ByteSource byteSource,
 GifImagingParameters params)
                       throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Gets image information from the specified ByteSource. Format-specific ImageParser implementations are expected to return a valid ImageInfo object or to throw an ImageReadException if unable to process the specified data.

The params argument provides a mechanism for individual implementations to pass optional information into the parser. Not all formats will require this capability. Because the base class may call this method with a null params argument, implementations should always include logic for ignoring null input.

Specified by:

getImageInfo in class AbstractImageParser<GifImagingParameters>

Parameters:

byteSource - A valid ByteSource object

params - Optional instructions for special-handling or interpretation of the input data (null objects are permitted and must be supported by implementations).

Returns:

A valid image information object describing the content extracted from the specified data.

Throws:

ImagingException - In the event that the specified content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful data access operation.

getImageSize

public Dimension getImageSize(ByteSource byteSource,
 GifImagingParameters params)
                       throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Gets the size of the image described by the specified ByteSource.

Specified by:

getImageSize in class AbstractImageParser<GifImagingParameters>

Parameters:

byteSource - A valid reference to a ByteSource.

params - Optional instructions for special-handling or interpretation of the input data.

Returns:

A valid instance of Dimension.

Throws:

ImagingException - In the event that the specified content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful read or access operation.

getMetadata

public ImageMetadata getMetadata(ByteSource byteSource,
 GifImagingParameters params)
                          throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Gets image metadata from the specified byte source. Format-specific ImageParser implementations are expected to return a valid IImageMetadata object or to throw an ImageReadException if unable to process the specified byte source.

The params argument provides a mechanism for individual implementations to pass optional information into the parser. Not all formats will require this capability. Because the base class may call this method with a null params argument, implementations should always include logic for ignoring null input.

Specified by:

getMetadata in class AbstractImageParser<GifImagingParameters>

Parameters:

byteSource - A valid byte source.

params - Optional instructions for special-handling or interpretation of the input data (null objects are permitted and must be supported by implementations).

Returns:

A valid, potentially subject-matter-specific implementation of the IImageMetadata interface describing the content extracted from the source content.

Throws:

ImagingException - In the event that the ByteSource content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful data read operation.

getName

public String getName()

Description copied from class: AbstractImageParser

Gets a descriptive name for the implementation of an ImageParser.

Specified by:

getName in class AbstractImageParser<GifImagingParameters>

Returns:

a valid, subject-matter-specific string.

getXmpXml

public String getXmpXml(ByteSource byteSource,
 XmpImagingParameters<GifImagingParameters> params)
                 throws ImagingException,
IOException

Extracts embedded XML metadata as XML string.

Specified by:

getXmpXml in interface XmpEmbeddable<GifImagingParameters>

Parameters:

byteSource - File containing image data.

params - Map of optional parameters, defined in ImagingConstants.

Returns:

Xmp Xml as String, if present. Otherwise, returns null.

Throws:

ImagingException - In the event that the specified content does not conform to the format of the specific parser implementation.

IOException - In the event of unsuccessful read or access operation.

readBlocks

private List<GifBlock> readBlocks(GifHeaderInfo ghi,
 InputStream is,
 boolean stopBeforeImageData,
 FormatCompliance formatCompliance)
                           throws ImagingException,
IOException

Throws:

ImagingException

IOException

readColorTable

private byte[] readColorTable(InputStream is,
 int tableSize)
                       throws IOException

Throws:

IOException

readFile

private GifImageContents readFile(ByteSource byteSource,
 boolean stopBeforeImageData)
                           throws ImagingException,
IOException

Throws:

ImagingException

IOException

readFile

private GifImageContents readFile(ByteSource byteSource,
 boolean stopBeforeImageData,
 FormatCompliance formatCompliance)
                           throws ImagingException,
IOException

Throws:

ImagingException

IOException

readGenericGifBlock

private GenericGifBlock readGenericGifBlock(InputStream is,
 int code)
                                     throws IOException

Throws:

IOException

readGenericGifBlock

private GenericGifBlock readGenericGifBlock(InputStream is,
 int code,
 byte[] first)
                                     throws IOException

Throws:

IOException

readGraphicControlExtension

private GraphicControlExtension readGraphicControlExtension(int code,
 InputStream is)
                                                     throws IOException

Throws:

IOException

readHeader

private GifHeaderInfo readHeader(InputStream is,
 FormatCompliance formatCompliance)
                          throws ImagingException,
IOException

Throws:

ImagingException

IOException

readImageDescriptor

private ImageDescriptor readImageDescriptor(GifHeaderInfo ghi,
 int blockCode,
 InputStream is,
 boolean stopBeforeImageData,
 FormatCompliance formatCompliance)
                                     throws ImagingException,
IOException

Throws:

ImagingException

IOException

readSubBlock

private byte[] readSubBlock(InputStream is)
                     throws IOException

Throws:

IOException

simplePow

private int simplePow(int base,
 int power)

writeAsSubBlocks

private void writeAsSubBlocks(byte[] bytes,
 OutputStream os)
                       throws IOException

Throws:

IOException

writeImage

public void writeImage(BufferedImage src,
 OutputStream os,
 GifImagingParameters params)
                throws ImagingException,
IOException

Description copied from class: AbstractImageParser

Writes the content of a BufferedImage to the specified output stream.

The params argument provides a mechanism for individual implementations to pass optional information into the parser. Not all formats will support this capability. Currently, some of the parsers do not check for null arguments.

Overrides:

writeImage in class AbstractImageParser<GifImagingParameters>

Parameters:

src - An image giving the source content for output

os - A valid output stream for storing the formatted image

params - optional parameters, defining format-specific instructions for output (such as selections for data compression, color models, etc.)

Throws:

ImagingException - In the event that the output format cannot handle the input image or invalid params are specified.

IOException - In the event of an write error from the output stream.