Package com.drew.metadata.gif

Class GifReader

java.lang.Object

com.drew.metadata.gif.GifReader

public class GifReader
extends Object

Reader of GIF encoded data. Resources:

• https://wiki.whatwg.org/wiki/GIF
• https://www.w3.org/Graphics/GIF/spec-gif89a.txt
• http://web.archive.org/web/20100929230301/http://www.etsimo.uniovi.es/gifanim/gif87a.txt

Field Summary

Fields

Modifier and Type	Field	Description
private static final String	GIF_87A_VERSION_IDENTIFIER
private static final String	GIF_89A_VERSION_IDENTIFIER

Constructor Summary

Constructors

Constructor	Description
GifReader()

Method Summary

Modifier and Type	Method	Description
void	extract(SequentialReader reader, Metadata metadata)
private static byte[]	gatherBytes(SequentialReader reader)
private static byte[]	gatherBytes(SequentialReader reader, int firstLength)
private static void	readApplicationExtensionBlock(SequentialReader reader, int blockSizeBytes, Metadata metadata)
private static GifCommentDirectory	readCommentBlock(SequentialReader reader, int blockSizeBytes)
private static GifControlDirectory	readControlBlock(SequentialReader reader)
private static void	readGifExtensionBlock(SequentialReader reader, Metadata metadata)
private static GifHeaderDirectory	readGifHeader(SequentialReader reader)
private static GifImageDirectory	readImageBlock(SequentialReader reader)
private static Directory	readPlainTextBlock(SequentialReader reader, int blockSizeBytes)
private static void	skipBlocks(SequentialReader reader)

Methods inherited from class java.lang.Object

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

Field Details

GIF_87A_VERSION_IDENTIFIER

private static final String GIF_87A_VERSION_IDENTIFIER

See Also:

• Constant Field Values

GIF_89A_VERSION_IDENTIFIER

private static final String GIF_89A_VERSION_IDENTIFIER

See Also:

• Constant Field Values

Constructor Details

GifReader

public GifReader()

Method Details

extract

public void extract(SequentialReader reader,
 Metadata metadata)

readGifHeader

private static GifHeaderDirectory readGifHeader(SequentialReader reader)
                                         throws IOException

Throws:

IOException

readGifExtensionBlock

private static void readGifExtensionBlock(SequentialReader reader,
 Metadata metadata)
                                   throws IOException

Throws:

IOException

readPlainTextBlock

private static Directory readPlainTextBlock(SequentialReader reader,
 int blockSizeBytes)
                                     throws IOException

Throws:

IOException

readCommentBlock

private static GifCommentDirectory readCommentBlock(SequentialReader reader,
 int blockSizeBytes)
                                             throws IOException

Throws:

IOException

readApplicationExtensionBlock

private static void readApplicationExtensionBlock(SequentialReader reader,
 int blockSizeBytes,
 Metadata metadata)
                                           throws IOException

Throws:

IOException

readControlBlock

private static GifControlDirectory readControlBlock(SequentialReader reader)
                                             throws IOException

Throws:

IOException

readImageBlock

private static GifImageDirectory readImageBlock(SequentialReader reader)
                                         throws IOException

Throws:

IOException

gatherBytes

private static byte[] gatherBytes(SequentialReader reader)
                           throws IOException

Throws:

IOException

gatherBytes

private static byte[] gatherBytes(SequentialReader reader,
 int firstLength)
                           throws IOException

Throws:

IOException

skipBlocks

private static void skipBlocks(SequentialReader reader)
                        throws IOException

Throws:

IOException