Abstract helper base class to access JPEG images. More...

#include <jpgimage.hpp>

Inheritance diagram for Exiv2::JpegBase:

[legend]

Protected Member Functions
Creators
	JpegBase (ImageType type, BasicIo::UniquePtr io, bool create, const byte initData[], size_t dataSize)
	Constructor that can either open an existing image or create a new image from scratch. If a new image is to be created, any existing data is overwritten. More...

Protected Member Functions inherited from Exiv2::Image
const std::string &	tagName (uint16_t tag)
	Return tag name for given tag id.

Manipulators
int	num_color_components_ {-1}
	image number of color components

std::string	sof_encoding_process_
	image encoding process

void	readMetadata () override
	Read all metadata supported by a specific image format from the image. Before this method is called, the image metadata will be cleared. More...

void	writeMetadata () override
	Write metadata back to the image. More...

void	printStructure (std::ostream &out, PrintStructureOption option, size_t depth) override
	Print out the structure of image file. More...

virtual int	writeHeader (BasicIo &oIo) const =0
	Writes the image header (aka signature) to the BasicIo instance. More...

Accessors
virtual bool	isThisType (BasicIo &iIo, bool advance) const =0
	Determine if the content of the BasicIo instance is of the type supported by this class. More...

Additional Inherited Members
Public Types inherited from Exiv2::Image
using	UniquePtr = std::unique_ptr< Image >
	Image auto_ptr type.

Public Member Functions inherited from Exiv2::Image
	Image (ImageType type, uint16_t supportedMetadata, BasicIo::UniquePtr io)
	Constructor taking the image type, a bitmap of the supported metadata types and an auto-pointer that owns an IO instance. See subclass constructor doc.

virtual	~Image ()=default
	Virtual Destructor.

ByteOrder	byteOrder () const
	Return the byte order in which the Exif metadata of the image is encoded. Initially, it is not set (invalidByteOrder).

bool	good () const
	Check if the Image instance is valid. Use after object construction. More...

virtual std::string	mimeType () const =0
	Return the MIME type of the image. More...

virtual uint32_t	pixelWidth () const
	Return the pixel width of the image.

virtual uint32_t	pixelHeight () const
	Return the pixel height of the image.

virtual const ExifData &	exifData () const
	Returns an ExifData instance containing currently buffered Exif data. More...

virtual const IptcData &	iptcData () const
	Returns an IptcData instance containing currently buffered IPTC data. More...

virtual const XmpData &	xmpData () const
	Returns an XmpData instance containing currently buffered XMP data. More...

virtual std::string	comment () const
	Return a copy of the image comment. May be an empty string.

virtual const std::string &	xmpPacket () const
	Return the raw XMP packet as a string.

virtual BasicIo &	io () const
	Return a reference to the BasicIo instance being used for Io. More...

AccessMode	checkMode (MetadataId metadataId) const
	Returns the access mode, i.e., the metadata functions, which this image supports for the metadata type metadataId. More...

bool	supportsMetadata (MetadataId metadataId) const
	Check if image supports a particular type of metadata. This method is deprecated. Use checkMode() instead.

bool	writeXmpFromPacket () const
	Return the flag indicating the source when writing XMP metadata.

const NativePreviewList &	nativePreviews () const
	Return list of native previews. This is meant to be used only by the PreviewManager.

void	setTypeSupported (ImageType imageType, uint16_t supportedMetadata)
	set type support for this image format

ImageType	imageType () const
	set type support for this image format

	Image (const Image &)=delete
	Copy constructor.

Image &	operator= (const Image &)=delete
	Assignment operator.

virtual void	setExifData (const ExifData &exifData)
	Assign new Exif data. The new Exif data is not written to the image until the writeMetadata() method is called. More...

virtual void	clearExifData ()
	Erase any buffered Exif data. Exif data is not removed from the actual image until the writeMetadata() method is called.

virtual void	setIptcData (const IptcData &iptcData)
	Assign new IPTC data. The new IPTC data is not written to the image until the writeMetadata() method is called. More...

virtual void	clearIptcData ()
	Erase any buffered IPTC data. IPTC data is not removed from the actual image until the writeMetadata() method is called.

virtual void	setXmpPacket (const std::string &xmpPacket)
	Assign a raw XMP packet. The new XMP packet is not written to the image until the writeMetadata() method is called. More...

virtual void	clearXmpPacket ()
	Erase the buffered XMP packet. XMP data is not removed from the actual image until the writeMetadata() method is called. More...

virtual void	setXmpData (const XmpData &xmpData)
	Assign new XMP data. The new XMP data is not written to the image until the writeMetadata() method is called. More...

virtual void	clearXmpData ()
	Erase any buffered XMP data. XMP data is not removed from the actual image until the writeMetadata() method is called. More...

virtual void	setComment (const std::string &comment)
	Set the image comment. The comment is written to the image when writeMetadata() is called.

virtual void	clearComment ()
	Erase any buffered comment. Comment is not removed from the actual image until the writeMetadata() method is called.

virtual void	setIccProfile (DataBuf &&iccProfile, bool bTestValid=true)
	Set the image iccProfile. The new profile is not written to the image until the writeMetadata() method is called. More...

virtual void	clearIccProfile ()
	Erase iccProfile. the profile is not removed from the actual image until the writeMetadata() method is called.

virtual bool	iccProfileDefined ()
	Returns the status of the ICC profile in the image instance.

virtual const DataBuf &	iccProfile () const
	return iccProfile

virtual void	setMetadata (const Image &image)
	Copy all existing metadata from source Image. The data is copied into internal buffers and is not written to the image until the writeMetadata() method is called. More...

virtual void	clearMetadata ()
	Erase all buffered metadata. Metadata is not removed from the actual image until the writeMetadata() method is called.

virtual ExifData &	exifData ()
	Returns an ExifData instance containing currently buffered Exif data. More...

virtual IptcData &	iptcData ()
	Returns an IptcData instance containing currently buffered IPTC data. More...

virtual XmpData &	xmpData ()
	Returns an XmpData instance containing currently buffered XMP data. More...

virtual std::string &	xmpPacket ()
	Return a modifiable reference to the raw XMP packet.

void	writeXmpFromPacket (bool flag)
	Determine the source when writing XMP. More...

void	setByteOrder (ByteOrder byteOrder)
	Set the byte order to encode the Exif metadata in. More...

void	printTiffStructure (BasicIo &io, std::ostream &out, PrintStructureOption option, size_t depth, size_t offset=0)
	Print out the structure of image file. More...

void	printIFDStructure (BasicIo &io, std::ostream &out, Exiv2::PrintStructureOption option, size_t start, bool bSwap, char c, size_t depth)
	Print out the structure of a TIFF IFD.

Static Public Member Functions inherited from Exiv2::Image
static bool	isBigEndianPlatform ()
	is the host platform bigEndian

static bool	isLittleEndianPlatform ()
	is the host platform littleEndian

static bool	isStringType (uint16_t type)

static bool	isShortType (uint16_t type)

static bool	isLongType (uint16_t type)

static bool	isLongLongType (uint16_t type)

static bool	isRationalType (uint16_t type)

static bool	is2ByteType (uint16_t type)

static bool	is4ByteType (uint16_t type)

static bool	is8ByteType (uint16_t type)

static bool	isPrintXMP (uint16_t type, Exiv2::PrintStructureOption option)

static bool	isPrintICC (uint16_t type, Exiv2::PrintStructureOption option)

static uint64_t	byteSwap (uint64_t value, bool bSwap)

static uint32_t	byteSwap (uint32_t value, bool bSwap)

static uint16_t	byteSwap (uint16_t value, bool bSwap)

static uint16_t	byteSwap2 (const DataBuf &buf, size_t offset, bool bSwap)

static uint32_t	byteSwap4 (const DataBuf &buf, size_t offset, bool bSwap)

static uint64_t	byteSwap8 (const DataBuf &buf, size_t offset, bool bSwap)

Static Protected Member Functions inherited from Exiv2::Image
static const char *	typeName (uint16_t tag)
	Return tag type for given tag id.

Protected Attributes inherited from Exiv2::Image
BasicIo::UniquePtr	io_
	Image data IO pointer.

ExifData	exifData_
	Exif data container.

IptcData	iptcData_
	IPTC data container.

XmpData	xmpData_
	XMP data container.

DataBuf	iccProfile_
	ICC buffer (binary data)

std::string	comment_
	User comment.

std::string	xmpPacket_
	XMP packet.

uint32_t	pixelWidth_ {0}
	image pixel width

uint32_t	pixelHeight_ {0}
	image pixel height

NativePreviewList	nativePreviews_
	list of native previews

Detailed Description

Abstract helper base class to access JPEG images.

Constructor & Destructor Documentation

◆ JpegBase()

Exiv2::JpegBase::JpegBase	(	ImageType	type,
		BasicIo::UniquePtr	io,
		bool	create,
		const byte	initData[],
		size_t	dataSize
	)

protected

Constructor that can either open an existing image or create a new image from scratch. If a new image is to be created, any existing data is overwritten.

Parameters

type	Image type.
io	An auto-pointer that owns a BasicIo instance used for reading and writing image metadata. Important: The constructor takes ownership of the passed in BasicIo instance through the auto-pointer. Callers should not continue to use the BasicIo instance after it is passed to this method. Use the Image::io() method to get a temporary reference.
create	Specifies if an existing image should be read (false) or if a new image should be created (true).
initData	Data to initialize newly created images. Only used when create is true. Should contain data for the smallest valid image of the calling subclass.
dataSize	Size of initData in bytes.

Member Function Documentation

◆ isThisType()

virtual bool Exiv2::JpegBase::isThisType	(	BasicIo &	iIo,
		bool	advance
	)		const

protectedpure virtual

Determine if the content of the BasicIo instance is of the type supported by this class.

The advance flag determines if the read position in the stream is moved (see below). This applies only if the type matches and the function returns true. If the type does not match, the stream position is not changed. However, if reading from the stream fails, the stream position is undefined. Consult the stream state to obtain more information in this case.

Parameters

iIo	BasicIo instance to read from.
advance	Flag indicating whether the position of the io should be advanced by the number of characters read to analyse the data (true) or left at its original position (false). This applies only if the type matches.

Returns: true if the data matches the type of this class;
false if the data does not match

Implemented in Exiv2::ExvImage, and Exiv2::JpegImage.

◆ printStructure()

void Exiv2::JpegBase::printStructure	(	std::ostream &	out,
		PrintStructureOption	option,
		size_t	depth
	)

overridevirtual

Print out the structure of image file.

Exceptions

Error if reading of the file fails or the image data is not valid (does not look like data of the specific image type).

Warning: This function is not thread safe and intended for exiv2 -pS for debugging.; You may need to put the stream into binary mode (see src/actions.cpp)

Reimplemented from Exiv2::Image.

◆ readMetadata()

void Exiv2::JpegBase::readMetadata ( )

overridevirtual

Read all metadata supported by a specific image format from the image. Before this method is called, the image metadata will be cleared.

This method returns success even if no metadata is found in the image. Callers must therefore check the size of individual metadata types before accessing the data.

Exceptions

Error if opening or reading of the file fails or the image data is not valid (does not look like data of the specific image type).

Implements Exiv2::Image.

◆ writeHeader()

virtual int Exiv2::JpegBase::writeHeader ( BasicIo & oIo ) const

protectedpure virtual

Writes the image header (aka signature) to the BasicIo instance.

Parameters

oIo	BasicIo instance that the header is written to.

Returns: 0 if successful;
4 if the output file can not be written to

Implemented in Exiv2::ExvImage, and Exiv2::JpegImage.

◆ writeMetadata()

void Exiv2::JpegBase::writeMetadata ( )

overridevirtual

Write metadata back to the image.

All existing metadata sections in the image are either created, replaced, or erased. If values for a given metadata type have been assigned, a section for that metadata type will either be created or replaced. If no values have been assigned to a given metadata type, any exists section for that metadata type will be removed from the image.

Exceptions

Error if the operation fails

Implements Exiv2::Image.

The documentation for this class was generated from the following file:

jpgimage.hpp

Protected Member Functions

Manipulators

Accessors

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ JpegBase()

Member Function Documentation

◆ isThisType()

◆ printStructure()

◆ readMetadata()

◆ writeHeader()

◆ writeMetadata()