内容

公共类型
特性
公共函数
重实现公共函数
公共槽
信号
静态公共成员
重实现保护函数
保护变量
详细描述

QCameraImageCapture 类

The QCameraImageCapture class is used for the recording of media content. 更多...

头：	#include <QCameraImageCapture>
qmake:	QT += multimedia
继承：	QObject and QMediaBindableInterface

公共类型

enum	CaptureDestination { CaptureToFile, CaptureToBuffer }
flags	CaptureDestinations
enum	DriveMode { SingleImageCapture }
enum	Error { NoError, NotReadyError, ResourceError, OutOfSpaceError, NotSupportedFeatureError, FormatError }

特性

readyForCapture : const bool

1 特性继承自 QObject

公共函数

	QCameraImageCapture (QMediaObject * mediaObject , QObject * parent = nullptr)
virtual	~QCameraImageCapture ()
QMultimedia::AvailabilityStatus	availability () const
QVideoFrame::PixelFormat	bufferFormat () const
QCameraImageCapture::CaptureDestinations	captureDestination () const
QImageEncoderSettings	encodingSettings () const
QCameraImageCapture::Error	error () const
QString	errorString () const
QString	imageCodecDescription (const QString & codec ) const
bool	isAvailable () const
bool	isCaptureDestinationSupported (QCameraImageCapture::CaptureDestinations destination ) const
bool	isReadyForCapture () const
void	setBufferFormat (const QVideoFrame::PixelFormat format )
void	setCaptureDestination (QCameraImageCapture::CaptureDestinations destination )
void	setEncodingSettings (const QImageEncoderSettings & settings )
QList<QVideoFrame::PixelFormat>	supportedBufferFormats () const
QStringList	supportedImageCodecs () const
QList<QSize>	supportedResolutions (const QImageEncoderSettings & settings = QImageEncoderSettings(), bool * continuous = nullptr) const

重实现公共函数

virtual QMediaObject *

mediaObject () const override

31 公共函数继承自 QObject
1 公共函数继承自 QMediaBindableInterface

公共槽

void	cancelCapture ()
int	capture (const QString & file = QString())

1 公共槽继承自 QObject

信号

void	bufferFormatChanged (QVideoFrame::PixelFormat format )
void	captureDestinationChanged (QCameraImageCapture::CaptureDestinations destination )
void	error (int id , QCameraImageCapture::Error error , const QString & errorString )
void	imageAvailable (int id , const QVideoFrame & frame )
void	imageCaptured (int id , const QImage & preview )
void	imageExposed (int id )
void	imageMetadataAvailable (int id , const QString & key , const QVariant & value )
void	imageSaved (int id , const QString & fileName )
void	readyForCaptureChanged (bool ready )

2 信号继承自 QObject

静态公共成员

const QMetaObject

staticMetaObject

9 静态公共成员继承自 QObject

重实现保护函数

virtual bool

setMediaObject (QMediaObject * mediaObject ) override

9 保护函数继承自 QObject
1 保护函数继承自 QMediaBindableInterface

保护变量

QCameraImageCapturePrivate *

d_ptr

详细描述

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

The QCameraImageCapture 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 .

camera = new QCamera;
viewfinder = new QCameraViewfinder();
viewfinder->show();
camera->setViewfinder(viewfinder);
imageCapture = new QCameraImageCapture(camera);
camera->setCaptureMode(QCamera::CaptureStillImage);
camera->start();
//on half pressed shutter button
camera->searchAndLock();
//on shutter button pressed
imageCapture->capture();
//on shutter button released
camera->unlock();

另请参阅 QCamera .

成员类型文档编制

enum QCameraImageCapture:: CaptureDestination
flags QCameraImageCapture:: CaptureDestinations

常量	值	描述
`QCameraImageCapture::CaptureToFile`	`0x01`	Capture the image to a file.
`QCameraImageCapture::CaptureToBuffer`	`0x02`	Capture the image to a buffer for further processing.

The CaptureDestinations type is a typedef for QFlags <CaptureDestination>. It stores an OR combination of CaptureDestination values.

enum QCameraImageCapture:: DriveMode

常量	值	描述
`QCameraImageCapture::SingleImageCapture`	`0`	Drive mode is capturing a single picture.

enum QCameraImageCapture:: Error

常量	值	描述
`QCameraImageCapture::NoError`	`0`	没有错误。
`QCameraImageCapture::NotReadyError`	`1`	The service is not ready for capture yet.
`QCameraImageCapture::ResourceError`	`2`	Device is not ready or not available.
`QCameraImageCapture::OutOfSpaceError`	`3`	No space left on device.
`QCameraImageCapture::NotSupportedFeatureError`	`4`	Device does not support stillimages capture.
`QCameraImageCapture::FormatError`	`5`	Current format is not supported.

特性文档编制

readyForCapture : const bool

This property holds whether the service is ready to capture a an image immediately.

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

访问函数：

bool	isReadyForCapture () const

通知程序信号：

void	readyForCaptureChanged (bool ready )

成员函数文档编制

QCameraImageCapture:: QCameraImageCapture ( QMediaObject * mediaObject , QObject * parent = nullptr)

Constructs a media recorder which records the media produced by mediaObject .

The parent 会被传递给 QMediaObject .

`[virtual]` QCameraImageCapture:: ~QCameraImageCapture ()

Destroys images capture object.

QMultimedia::AvailabilityStatus QCameraImageCapture:: availability () const

Returns the availability of this functionality.

QVideoFrame::PixelFormat QCameraImageCapture:: bufferFormat () const

Returns the buffer image capture format being used.

另请参阅 supportedBufferFormats () 和 setBufferFormat ().

`[signal]` void QCameraImageCapture:: bufferFormatChanged ( QVideoFrame::PixelFormat format )

Signal emitted when the buffer format for the buffer image capture has changed.

`[slot]` void QCameraImageCapture:: cancelCapture ()

Cancel incomplete capture requests. Already captured and queused for proicessing images may be discarded.

`[slot]` int QCameraImageCapture:: capture (const QString & file = QString())

Capture the image and save it to file . This operation is asynchronous in majority of cases, followed by signals QCameraImageCapture::imageExposed (), QCameraImageCapture::imageCaptured (), QCameraImageCapture::imageSaved () 或 QCameraImageCapture::error ().

If an empty file is passed, the camera backend choses 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 () 和 imageSaved () 信号。

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.

QCameraImageCapture::capture returns the capture Id parameter, used with imageExposed (), imageCaptured () 和 imageSaved () 信号。

另请参阅 isReadyForCapture ().

QCameraImageCapture::CaptureDestinations QCameraImageCapture:: captureDestination () const

Returns the image capture destination being used.

另请参阅 isCaptureDestinationSupported () 和 setCaptureDestination ().

`[signal]` void QCameraImageCapture:: captureDestinationChanged ( QCameraImageCapture::CaptureDestinations destination )

Signal emitted when the capture destination 已改变。

QImageEncoderSettings QCameraImageCapture:: encodingSettings () const

Returns the image encoder settings being used.

另请参阅 setEncodingSettings ().

QCameraImageCapture::Error QCameraImageCapture:: error () const

返回当前错误状态。

另请参阅 errorString ().

`[signal]` void QCameraImageCapture:: error ( int id , QCameraImageCapture::Error error , const QString & errorString )

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

注意： 信号 error 在此类中被重载。通过使用函数指针句法连接到此信号，Qt 提供用于获得如此范例展示的函数指针的方便帮助程序：

connect(cameraImageCapture, QOverload<int, QCameraImageCapture::Error, const QString &>::of(&QCameraImageCapture::error),
    [=](int id, QCameraImageCapture::Error error, const QString &errorString){ /* ... */ });

QString QCameraImageCapture:: errorString () const

Returns a string describing the current error state.

另请参阅 error ().

`[signal]` void QCameraImageCapture:: imageAvailable ( int id , const QVideoFrame & frame )

Signal emitted when the frame with request id 可用。

`[signal]` void QCameraImageCapture:: imageCaptured ( int id , const QImage & preview )

Signal emitted when the frame with request id was captured, but not processed and saved yet. Frame preview can be displayed to user.

QString QCameraImageCapture:: imageCodecDescription (const QString & codec ) const

返回描述为图像 codec .

`[signal]` void QCameraImageCapture:: imageExposed ( int id )

Signal emitted when the frame with request id was exposed.

`[signal]` void QCameraImageCapture:: imageMetadataAvailable ( int id , const QString & key , const QVariant & value )

Signals that a metadata for an image with request id is available. Also includes the key and value of the metadata.

This signal is emitted between imageExposed and imageSaved signals.

`[signal]` void QCameraImageCapture:: imageSaved ( int id , const QString & fileName )

Signal emitted when the frame with request id was saved to fileName .

bool QCameraImageCapture:: isAvailable () const

Returns true if the images capture service ready to use.

bool QCameraImageCapture:: isCaptureDestinationSupported ( QCameraImageCapture::CaptureDestinations destination ) const

Returns true if the image capture destination is supported; otherwise returns false.

另请参阅 captureDestination () 和 setCaptureDestination ().

`[override virtual]` QMediaObject *QCameraImageCapture:: mediaObject () const

重实现自 QMediaBindableInterface::mediaObject ().

另请参阅 setMediaObject ().

`[signal]` void QCameraImageCapture:: readyForCaptureChanged ( bool ready )

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

注意： 通知程序信号对于特性 readyForCapture .

void QCameraImageCapture:: setBufferFormat (const QVideoFrame::PixelFormat format )

Sets the buffer image capture format to be used.

另请参阅 bufferFormat (), supportedBufferFormats ()，和 captureDestination ().

void QCameraImageCapture:: setCaptureDestination ( QCameraImageCapture::CaptureDestinations destination )

Sets the capture destination to be used.

另请参阅 isCaptureDestinationSupported () 和 captureDestination ().

void QCameraImageCapture:: setEncodingSettings (const QImageEncoderSettings & settings )

设置图像编码 settings .

If some parameters are not specified, or null settings are passed, the encoder choose the default encoding parameters.

另请参阅 encodingSettings ().

`[override virtual protected]` bool QCameraImageCapture:: setMediaObject ( QMediaObject * mediaObject )

重实现自 QMediaBindableInterface::setMediaObject ().

另请参阅 mediaObject ().

QList < QVideoFrame::PixelFormat > QCameraImageCapture:: supportedBufferFormats () const

Returns the list of supported buffer image capture formats.

另请参阅 bufferFormat () 和 setBufferFormat ().

QStringList QCameraImageCapture:: supportedImageCodecs () const

返回支持的图像编解码器列表。

QList < QSize > QCameraImageCapture:: supportedResolutions (const QImageEncoderSettings & settings = QImageEncoderSettings(), bool * continuous = nullptr) const

Returns a list of resolutions images can be encoded at.

若非 null 图像 settings parameter is passed, the returned list is reduced to resolution supported with partial settings like image codec or quality applied.

If the encoder supports arbitrary resolutions within the supported range, * continuous 被设为 true，否则 * continuous 被设为 false。

另请参阅 QImageEncoderSettings::resolution ().

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