QAbstractVideoSurface Class

成员函数

QAbstractVideoSurface::QAbstractVideoSurface(QObject *parent = Q_NULLPTR)

Constructs a video surface with the given parent.

QAbstractVideoSurface::~QAbstractVideoSurface()

Destroys a video surface.

[signal] void QAbstractVideoSurface::activeChanged(bool active)

Signals that the active state of a video surface has changed.

参见 isActive(), start(), and stop().

Error QAbstractVideoSurface::error() const

Returns the last error that occurred.

If a surface fails to start(), or stops unexpectedly this function can be called to discover what error occurred.

参见 setError().

bool QAbstractVideoSurface::isActive() const

Indicates whether a video surface has been started.

Returns true if the surface has been started, and false otherwise.

[virtual] bool QAbstractVideoSurface::isFormatSupported(const QVideoSurfaceFormat &format) const

Tests a video surface format to determine if a surface can accept it.

Returns true if the format is supported by the surface, and false otherwise.

[signal] void QAbstractVideoSurface::nativeResolutionChanged(const QSize &resolution)

Signals the native resolution of video surface has changed.

Note: Notifier signal for property nativeResolution.

[virtual] QVideoSurfaceFormat QAbstractVideoSurface::nearestFormat(const QVideoSurfaceFormat &format) const

Returns a supported video surface format that is similar to format.

A similar surface format is one that has the same pixel format and handle type but may differ in some of the other properties. For example, if there are restrictions on the frame sizes a video surface can accept it may suggest a format with a larger frame size and a viewport the size of the original frame size.

If the format is already supported it will be returned unchanged, or if there is no similar supported format an invalid format will be returned.

[pure virtual] bool QAbstractVideoSurface::present(const QVideoFrame &frame)

Presents a video frame.

Returns true if the frame was presented, and false if an error occurred.

Not all surfaces will block until the presentation of a frame has completed. Calling present() on a non-blocking surface may fail if called before the presentation of a previous frame has completed. In such cases the surface may not return to a ready state until it has had an opportunity to process events.

If present() fails for any other reason the surface should immediately enter the stopped state and an error() value will be set.

A video surface must be in the started state for present() to succeed, and the format of the video frame must be compatible with the current video surface format.

参见 error().

[protected] void QAbstractVideoSurface::setError(Error error)

Sets the value of error() to error.

This can be called by implementors of this interface to communicate what the most recent error was.

参见 error().

[protected] void QAbstractVideoSurface::setNativeResolution(const QSize &resolution)

Set the video surface native resolution.

This function can be called by implementors of this interface to specify to frame producers what the native resolution of this surface is.

参见 nativeResolution().

[virtual] bool QAbstractVideoSurface::start(const QVideoSurfaceFormat &format)

Starts a video surface presenting format frames.

Returns true if the surface was started, and false if an error occurred.

Note: You must call the base class implementation of start() at the end of your implementation.

参见 isActive() and stop().

[virtual] void QAbstractVideoSurface::stop()

Stops a video surface presenting frames and releases any resources acquired in start().

Note: You must call the base class implementation of stop() at the start of your implementation.

参见 isActive() and start().

[signal] void QAbstractVideoSurface::supportedFormatsChanged()

Signals that the set of formats supported by a video surface has changed.

参见 supportedPixelFormats() and isFormatSupported().

[pure virtual] QList<QVideoFrame::PixelFormat> QAbstractVideoSurface::supportedPixelFormats(QAbstractVideoBuffer::HandleType type = QAbstractVideoBuffer::NoHandle) const

Returns a list of pixel formats a video surface can present for a given handle type.

The pixel formats returned for the QAbstractVideoBuffer::NoHandle type are valid for any buffer that can be mapped in read-only mode.

Types that are first in the list can be assumed to be faster to render.

QVideoSurfaceFormat QAbstractVideoSurface::surfaceFormat() const

Returns the format of a video surface.

[signal] void QAbstractVideoSurface::surfaceFormatChanged(const QVideoSurfaceFormat &format)

Signals that the configured format of a video surface has changed.

参见 surfaceFormat() and start().