QImageCapture Class Reference

\inmodule QtMultimedia More...

#include <qimagecapture.h>

Inheritance diagram for QImageCapture:

Collaboration diagram for QImageCapture:

Public Types
enum	Error {   NoError , NotReadyError , ResourceError , OutOfSpaceError ,   NotSupportedFeatureError , FormatError }
	\value NoError No Errors. More...
enum	Quality {   VeryLowQuality , LowQuality , NormalQuality , HighQuality ,   VeryHighQuality }
	Enumerates quality encoding levels. More...
enum	FileFormat {   UnspecifiedFormat , JPEG , PNG , WebP ,   Tiff , LastFileFormat = Tiff }
	Choose one of the following image formats: More...

Public Slots
int	captureToFile (const QString &location=QString())
	Capture the image and save it to file.
int	capture ()
	Capture the image and make it available as a QImage.
Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals
void	errorChanged ()
void	errorOccurred (int id, QImageCapture::Error error, const QString &errorString)
	Signals that the capture request id has failed with an error and errorString description.
void	readyForCaptureChanged (bool ready)
	Signals that a camera's ready for capture state has changed.
void	metaDataChanged ()
void	fileFormatChanged ()
void	qualityChanged ()
void	resolutionChanged ()
	Signals when the image resolution changes.
void	imageExposed (int id)
	Signal emitted when the frame with request id was exposed.
void	imageCaptured (int id, const QImage &preview)
	Signal emitted when the frame with request id was captured, but not processed and saved yet.
void	imageMetadataAvailable (int id, const QMediaMetaData &metaData)
	Signals that an image identified by id has metaData.
void	imageAvailable (int id, const QVideoFrame &frame)
	Signal emitted when the frame with request id is available.
void	imageSaved (int id, const QString &fileName)
	Signal emitted when QImageCapture::CaptureToFile is set and the frame with request id was saved to fileName.
Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.
void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.

Public Member Functions
	QImageCapture (QObject *parent=nullptr)
	Constructs a image capture object, from a parent, that can capture individual still images produced by a camera.
	~QImageCapture ()
	Destroys images capture object.
bool	isAvailable () const
	Returns true if the images capture service ready to use.
QMediaCaptureSession *	captureSession () const
	Returns the capture session this camera is connected to, or a nullptr if the camera is not connected to a capture session.
Error	error () const
QString	errorString () const
bool	isReadyForCapture () const
FileFormat	fileFormat () const
void	setFileFormat (FileFormat format)
	Sets the image format.
QSize	resolution () const
	Returns the resolution of the encoded image.
void	setResolution (const QSize &)
	Sets the resolution of the encoded image.
void	setResolution (int width, int height)
	Sets the width and height of the resolution of the encoded image.
Quality	quality () const
void	setQuality (Quality quality)
	Sets the image encoding quality.
QMediaMetaData	metaData () const
void	setMetaData (const QMediaMetaData &metaData)
	Replaces any existing meta data, to be embedded into the captured image, with a set of metaData.
void	addMetaData (const QMediaMetaData &metaData)
	Adds additional metaData to any existing meta data, that is embedded into the captured image.
Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.
virtual	~QObject ()
	Destroys the object, deleting all its child objects.
virtual bool	event (QEvent *event)
	This virtual function receives events to an object and should return true if the event e was recognized and processed.
virtual bool	eventFilter (QObject *watched, QEvent *event)
	Filters events if this object has been installed as an event filter for the watched object.
QString	objectName () const
Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.
void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QBindable< QString >	bindableObjectName ()
bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false.
bool	isWindowType () const
	Returns true if the object is a window; otherwise returns false.
bool	isQuickItemType () const
	Returns true if the object is a QQuickItem; otherwise returns false.
bool	signalsBlocked () const noexcept
	Returns true if signals are blocked; otherwise returns false.
bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).
QThread *	thread () const
	Returns the thread in which the object lives.
void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children.
int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.
int	startTimer (std::chrono::milliseconds time, Qt::TimerType timerType=Qt::CoarseTimer)
void	killTimer (int id)
	Kills the timer with timer identifier, id.
template<typename T >
T	findChild (const QString &aName=QString(), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.
template<typename T >
QList< T >	findChildren (const QString &aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.
template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
const QObjectList &	children () const
	Returns a list of child objects.
void	setParent (QObject *parent)
	Makes the object a child of parent.
void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.
void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.
QMetaObject::Connection	connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const
bool	disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const
bool	disconnect (const QObject *receiver, const char *member=nullptr) const
void	dumpObjectTree () const
	Dumps a tree of children to the debug output.
void	dumpObjectInfo () const
	Dumps information about signal connections, etc.
bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.
bool	setProperty (const char *name, QVariant &&value)
QVariant	property (const char *name) const
	Returns the value of the object's name property.
QList< QByteArray >	dynamicPropertyNames () const
QBindingStorage *	bindingStorage ()
const QBindingStorage *	bindingStorage () const
QObject *	parent () const
	Returns a pointer to the parent object.
bool	inherits (const char *classname) const
	Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false.

Static Public Member Functions
static QList< FileFormat >	supportedFormats ()
	Returns a list of supported file formats.
static QString	fileFormatName (FileFormat c)
	Returns the name of the given format, f.
static QString	fileFormatDescription (FileFormat c)
	Returns the description of the given file format, f.
Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe
static QMetaObject::Connection	connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)
template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)
static bool	disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member)
	\threadsafe
static bool	disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member)
static bool	disconnect (const QMetaObject::Connection &)
	Disconnect a connection.
template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot)
template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero)

Properties
bool	readyForCapture
	Holds true if the camera is ready to capture an image immediately.
QMediaMetaData	metaData
	The meta data that will get embedded into the image.
Error	error
	Returns the current error state.
QString	errorString
	Returns a string describing the current error state.
FileFormat	fileFormat
	The image format.
Quality	quality
	The image encoding quality.
Properties inherited from QObject
QString	objectName
	the name of this object

Friends
class	QMediaCaptureSession

Additional Inherited Members
Protected Member Functions inherited from QObject
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.
int	senderSignalIndex () const
int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.
bool	isSignalConnected (const QMetaMethod &signal) const
virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.
virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.
virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.
virtual void	connectNotify (const QMetaMethod &signal)
virtual void	disconnectNotify (const QMetaMethod &signal)
	QObject (QObjectPrivate &dd, QObject *parent=nullptr)
Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr
Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.
template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()
template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()
	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

\inmodule QtMultimedia

The QImageCapture class is used for the recording of media content.

The QImageCapture class is a high level images recording class. It's not intended to be used alone but for accessing the media recording functions of other media objects, like QCamera.

See also

QCamera

Definition at line 25 of file qimagecapture.h.

Member Enumeration Documentation

Error

enum QImageCapture::Error

\value NoError No Errors.

\value NotReadyError The service is not ready for capture yet. \value ResourceError Device is not ready or not available. \value OutOfSpaceError No space left on device. \value NotSupportedFeatureError Device does not support stillimages capture. \value FormatError Current format is not supported.

Enumerator
NoError
NotReadyError
ResourceError
OutOfSpaceError
NotSupportedFeatureError
FormatError

Definition at line 35 of file qimagecapture.h.

FileFormat

enum QImageCapture::FileFormat

Choose one of the following image formats:

\value UnspecifiedFormat No format specified \value JPEG .jpg or .jpeg format \value PNG .png format \value WebP .webp format \value Tiff .tiff format \omitvalue LastFileFormat

Enumerator
UnspecifiedFormat
JPEG
PNG
WebP
Tiff
LastFileFormat

Definition at line 56 of file qimagecapture.h.

Quality

enum QImageCapture::Quality

Enumerates quality encoding levels.

\value VeryLowQuality \value LowQuality \value NormalQuality \value HighQuality \value VeryHighQuality

Enumerator
VeryLowQuality
LowQuality
NormalQuality
HighQuality
VeryHighQuality

Definition at line 46 of file qimagecapture.h.

Constructor & Destructor Documentation

QImageCapture()

QImageCapture::QImageCapture ( QObject *  parent = nullptr )

explicit

Constructs a image capture object, from a parent, that can capture individual still images produced by a camera.

You must connect both an image capture object and a QCamera to a capture session to capture images.

Definition at line 80 of file qimagecapture.cpp.

References QObject::connect(), QPlatformMediaIntegration::createImageCapture(), d, error, imageAvailable(), imageCaptured(), imageExposed(), imageMetadataAvailable(), imageSaved(), QPlatformMediaIntegration::instance(), NotReadyError, qWarning, readyForCaptureChanged(), SIGNAL, and SLOT.

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~QImageCapture()

QImageCapture::~QImageCapture

(

)

Destroys images capture object.

Definition at line 130 of file qimagecapture.cpp.

References QImageCapturePrivate::captureSession, and QMediaCaptureSession::setImageCapture().

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Member Function Documentation

addMetaData()

void QImageCapture::addMetaData

(

const QMediaMetaData &

metaData

)

Adds additional metaData to any existing meta data, that is embedded into the captured image.

Definition at line 213 of file qimagecapture.cpp.

References d, QMediaMetaData::keys(), metaData, setMetaData(), and QMediaMetaData::value().

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capture

int QImageCapture::capture ( )

slot

Capture the image and make it available as a QImage.

This operation is asynchronous in majority of cases, followed by signals QImageCapture::imageExposed(), QImageCapture::imageCaptured() or QImageCapture::error().

QImageCapture::capture returns the capture Id parameter, used with imageExposed(), imageCaptured() and imageSaved() signals.

See also

isReadyForCapture()

Definition at line 298 of file qimagecapture.cpp.

References d.

Referenced by camera_blah(), and overview_still().

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captureSession()

QMediaCaptureSession * QImageCapture::captureSession

(

)

const

Returns the capture session this camera is connected to, or a nullptr if the camera is not connected to a capture session.

Use QMediaCaptureSession::setImageCapture() to connect the image capture to a session.

Definition at line 152 of file qimagecapture.cpp.

References QImageCapturePrivate::captureSession.

Referenced by QMediaCaptureSession::setImageCapture().

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captureToFile

int QImageCapture::captureToFile ( const QString &  file = QString() )

slot

Capture the image and save it to file.

This operation is asynchronous in majority of cases, followed by signals QImageCapture::imageExposed(), QImageCapture::imageCaptured(), QImageCapture::imageSaved() or QImageCapture::error().

If an empty file is passed, the camera back end chooses the default location and naming scheme for photos on the system, if only file name without full path is specified, the image will be saved to the default directory, with a full path reported with imageCaptured() and imageSaved() signals.

QCamera saves all the capture parameters like exposure settings or image processing parameters, so changes to camera parameters after capture() is called do not affect previous capture requests.

QImageCapture::capture returns the capture Id parameter, used with imageExposed(), imageCaptured() and imageSaved() signals.

See also

isReadyForCapture()

Definition at line 268 of file qimagecapture.cpp.

References d, file, isReadyForCapture(), NotReadyError, and tr.

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error()

QImageCapture::Error QImageCapture::error

(

)

const

Definition at line 165 of file qimagecapture.cpp.

errorChanged

void QImageCapture::errorChanged ( )

signal

errorOccurred

QImageCapture::errorOccurred ( int  id, QImageCapture::Error  error, const QString &  errorString  )

signal

Signals that the capture request id has failed with an error and errorString description.

errorString()

QString QImageCapture::errorString

(

)

const

Definition at line 178 of file qimagecapture.cpp.

fileFormat()

QImageCapture::FileFormat QImageCapture::fileFormat

(

)

const

Definition at line 373 of file qimagecapture.cpp.

References d, and UnspecifiedFormat.

fileFormatChanged

void QImageCapture::fileFormatChanged ( )

signal

Referenced by setFileFormat().

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fileFormatDescription()

QString QImageCapture::fileFormatDescription ( QImageCapture::FileFormat  f )

static

Returns the description of the given file format, f.

Definition at line 434 of file qimagecapture.cpp.

References QString::fromUtf8(), JPEG, PNG, Tiff, UnspecifiedFormat, and WebP.

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fileFormatName()

QString QImageCapture::fileFormatName ( QImageCapture::FileFormat  f )

static

Returns the name of the given format, f.

Definition at line 408 of file qimagecapture.cpp.

References QString::fromUtf8(), JPEG, PNG, Tiff, UnspecifiedFormat, and WebP.

Referenced by QQnxImageCapture::capture().

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imageAvailable

QImageCapture::imageAvailable ( int  id, const QVideoFrame &  frame  )

signal

Signal emitted when the frame with request id is available.

Referenced by QImageCapture().

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imageCaptured

QImageCapture::imageCaptured ( int  id, const QImage &  preview  )

signal

Signal emitted when the frame with request id was captured, but not processed and saved yet.

Frame preview can be displayed to user.

Referenced by QImageCapture(), and QQuickImageCapture::QQuickImageCapture().

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imageExposed

QImageCapture::imageExposed ( int  id )

signal

Signal emitted when the frame with request id was exposed.

Referenced by QImageCapture().

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imageMetadataAvailable

void QImageCapture::imageMetadataAvailable ( int  id, const QMediaMetaData &  metaData  )

signal

Signals that an image identified by id has metaData.

Referenced by QImageCapture().

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imageSaved

QImageCapture::imageSaved ( int  id, const QString &  fileName  )

signal

Signal emitted when QImageCapture::CaptureToFile is set and the frame with request id was saved to fileName.

Referenced by QImageCapture().

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isAvailable()

bool QImageCapture::isAvailable

(

)

const

Returns true if the images capture service ready to use.

Definition at line 140 of file qimagecapture.cpp.

isReadyForCapture()

bool QImageCapture::isReadyForCapture

(

)

const

Definition at line 229 of file qimagecapture.cpp.

References camera, d, and QCamera::isActive().

Referenced by captureToFile().

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metaData()

QMediaMetaData QImageCapture::metaData

(

)

const

Definition at line 190 of file qimagecapture.cpp.

References d.

metaDataChanged

void QImageCapture::metaDataChanged ( )

signal

Referenced by setMetaData().

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quality()

QImageCapture::Quality QImageCapture::quality

(

)

const

Definition at line 518 of file qimagecapture.cpp.

References d, and NormalQuality.

qualityChanged

void QImageCapture::qualityChanged ( )

signal

readyForCaptureChanged

QImageCapture::readyForCaptureChanged ( bool  ready )

signal

Signals that a camera's ready for capture state has changed.

Referenced by QImageCapture().

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resolution()

QSize QImageCapture::resolution

(

)

const

Returns the resolution of the encoded image.

Definition at line 461 of file qimagecapture.cpp.

References d.

Referenced by setResolution().

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resolutionChanged

void QImageCapture::resolutionChanged ( )

signal

Signals when the image resolution changes.

Referenced by setQuality(), and setResolution().

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setFileFormat()

void QImageCapture::setFileFormat

(

QImageCapture::FileFormat

format

)

Sets the image format.

Definition at line 382 of file qimagecapture.cpp.

References d, emit, fileFormatChanged(), and fmt.

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setMetaData()

void QImageCapture::setMetaData

(

const QMediaMetaData &

metaData

)

Replaces any existing meta data, to be embedded into the captured image, with a set of metaData.

Definition at line 200 of file qimagecapture.cpp.

References d, emit, metaData, and metaDataChanged().

Referenced by addMetaData().

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setQuality()

void QImageCapture::setQuality

(

Quality

quality

)

Sets the image encoding quality.

Definition at line 527 of file qimagecapture.cpp.

References d, emit, fmt, quality, and resolutionChanged().

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setResolution() [1/2]

void QImageCapture::setResolution

(

const QSize &

resolution

)

Sets the resolution of the encoded image.

An empty QSize indicates the encoder should make an optimal choice based on what is available from the image source and the limitations of the codec.

Definition at line 479 of file qimagecapture.cpp.

References d, emit, fmt, resolution(), and resolutionChanged().

Referenced by setResolution().

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setResolution() [2/2]

void QImageCapture::setResolution	(	int	width,
		int	height
	)

Sets the width and height of the resolution of the encoded image.

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 497 of file qimagecapture.cpp.

References setResolution().

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supportedFormats()

QList< QImageCapture::FileFormat > QImageCapture::supportedFormats ( )

static

Returns a list of supported file formats.

See also

{QImageCapture::}{FileFormat}

Definition at line 400 of file qimagecapture.cpp.

References QPlatformMediaIntegration::formatInfo(), QPlatformMediaFormatInfo::imageFormats, and QPlatformMediaIntegration::instance().

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Friends And Related Symbol Documentation

QMediaCaptureSession

friend class QMediaCaptureSession

friend

Definition at line 121 of file qimagecapture.h.

Property Documentation

error

QImageCapture::error

read

Returns the current error state.

See also

errorString()

Definition at line 130 of file qimagecapture.h.

Referenced by QImageCapture().

errorString

QImageCapture::errorString

read

Returns a string describing the current error state.

See also

error()

Definition at line 130 of file qimagecapture.h.

fileFormat

QImageCapture::fileFormat

read

The image format.

Definition at line 130 of file qimagecapture.h.

metaData

QImageCapture::metaData

readwrite

The meta data that will get embedded into the image.

Note

Additional fields such as a time stamp or location may get added by the camera back end.

Definition at line 130 of file qimagecapture.h.

Referenced by addMetaData(), and setMetaData().

quality

QImageCapture::quality

read

The image encoding quality.

Definition at line 130 of file qimagecapture.h.

Referenced by setQuality().

readyForCapture

QImageCapture::readyForCapture

read

Holds true if the camera is ready to capture an image immediately.

Calling capture() while readyForCapture is false is not permitted and results in an error.

Definition at line 130 of file qimagecapture.h.

---

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

• qtmultimedia/src/multimedia/camera/qimagecapture.h
• qtmultimedia/src/multimedia/camera/qimagecapture.cpp