com.drew.imaging.png

Class PngMetadataReader

java.lang.Object

com.drew.imaging.png.PngMetadataReader

public class PngMetadataReader
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
private static java.util.Set<PngChunkType>	_desiredChunkTypes
private static java.nio.charset.Charset	_latin1Encoding The PNG spec states that ISO_8859_1 (Latin-1) encoding should be used for: "tEXt" and "zTXt" chunks, both for keys and values (https://www.w3.org/TR/PNG/#11tEXt) "iCCP" chunks, for the profile name (https://www.w3.org/TR/PNG/#11iCCP) "sPLT" chunks, for the palette name (https://www.w3.org/TR/PNG/#11sPLT) Note that "iTXt" chunks use UTF-8 encoding (https://www.w3.org/TR/PNG/#11iTXt).

Constructor Summary

Constructors

Constructor and Description
PngMetadataReader()

Method Summary

Modifier and Type	Method and Description
private static void	processChunk(Metadata metadata, PngChunk chunk)
static Metadata	readMetadata(java.io.File file)
static Metadata	readMetadata(java.io.InputStream inputStream)

Methods inherited from class java.lang.Object

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

Field Detail

_desiredChunkTypes

private static java.util.Set<PngChunkType> _desiredChunkTypes

_latin1Encoding

private static java.nio.charset.Charset _latin1Encoding

The PNG spec states that ISO_8859_1 (Latin-1) encoding should be used for:

• "tEXt" and "zTXt" chunks, both for keys and values (https://www.w3.org/TR/PNG/#11tEXt)
• "iCCP" chunks, for the profile name (https://www.w3.org/TR/PNG/#11iCCP)
• "sPLT" chunks, for the palette name (https://www.w3.org/TR/PNG/#11sPLT)

Note that "iTXt" chunks use UTF-8 encoding (https://www.w3.org/TR/PNG/#11iTXt).

For more guidance: http://www.w3.org/TR/PNG-Decoders.html#D.Text-chunk-processing

Constructor Detail

PngMetadataReader

public PngMetadataReader()

Method Detail

readMetadata

public static Metadata readMetadata(java.io.File file)
                             throws PngProcessingException,
                                    java.io.IOException

Throws:

PngProcessingException

java.io.IOException

readMetadata

public static Metadata readMetadata(java.io.InputStream inputStream)
                             throws PngProcessingException,
                                    java.io.IOException

Throws:

PngProcessingException

java.io.IOException

processChunk

private static void processChunk(Metadata metadata,
                                 PngChunk chunk)
                          throws PngProcessingException,
                                 java.io.IOException

Throws:

PngProcessingException

java.io.IOException