Qt 5.9 | Qt Multimedia | C++ Classes | QCameraViewfinderSettings

Qt 5.9.4 Reference Documentation

# QCameraViewfinderSettings Class

The QCameraViewfinderSettings class provides a set of viewfinder settings. More...

Header: | #include <QCameraViewfinderSettings>
qmake: | QT += multimedia
Since: | Qt 5.5

- List of all members, including inherited members

## Public Functions

| QCameraViewfinderSettings()
| QCameraViewfinderSettings(const QCameraViewfinderSettings &other)
| ~QCameraViewfinderSettings()
bool | isNull() const
qreal | maximumFrameRate() const
qreal | minimumFrameRate() const
QSize | pixelAspectRatio() const
QVideoFrame::PixelFormat | pixelFormat() const
QSize | resolution() const
void | setMaximumFrameRate(qreal rate)
void | setMinimumFrameRate(qreal rate)
void | setPixelAspectRatio(const QSize &ratio)
void | setPixelAspectRatio(int horizontal, int vertical)
void | setPixelFormat(QVideoFrame::PixelFormat format)
void | setResolution(const QSize &resolution)
void | setResolution(int width, int height)
void | swap(QCameraViewfinderSettings &other)
QCameraViewfinderSettings & | operator=(const QCameraViewfinderSettings &other)
QCameraViewfinderSettings & | operator=(QCameraViewfinderSettings &&other)

## Related Non-Members

bool | operator!=(const QCameraViewfinderSettings &lhs, const QCameraViewfinderSettings &rhs)

## Detailed Description

The QCameraViewfinderSettings class provides a set of viewfinder settings.

A viewfinder settings object is used to specify the viewfinder settings used by QCamera. Viewfinder settings are selected by constructing a QCameraViewfinderSettings object, setting the desired properties and then passing it to a QCamera instance using the QCamera::setViewfinderSettings() function.

      QCameraViewfinderSettings viewfinderSettings;
      viewfinderSettings.setResolution(640, 480);
      viewfinderSettings.setMinimumFrameRate(15.0);
      viewfinderSettings.setMaximumFrameRate(30.0);

      camera->setViewfinderSettings(viewfinderSettings);

Different cameras may have different capabilities. The application should query the camera capabilities before setting parameters. For example, the application should call QCamera::supportedViewfinderResolutions() before calling setResolution().

See also QCamera.

## Member Function Documentation

### QCameraViewfinderSettings::QCameraViewfinderSettings()

Constructs a null viewfinder settings object.

### QCameraViewfinderSettings::QCameraViewfinderSettings(const QCameraViewfinderSettings &other)

Constructs a copy of the viewfinder settings object other.

### QCameraViewfinderSettings::~QCameraViewfinderSettings()

Destroys a viewfinder settings object.

### bool QCameraViewfinderSettings::isNull() const

Identifies if a viewfinder settings object is uninitalized.

Returns true if the settings are null, and false if they are not.

### qreal QCameraViewfinderSettings::maximumFrameRate() const

Returns the viewfinder maximum frame rate in frames per second.

See also setMaximumFrameRate() and minimumFrameRate().

### qreal QCameraViewfinderSettings::minimumFrameRate() const

Returns the viewfinder minimum frame rate in frames per second.

See also setMinimumFrameRate() and maximumFrameRate().

### QSize QCameraViewfinderSettings::pixelAspectRatio() const

Returns the viewfinder pixel aspect ratio.

See also setPixelAspectRatio().

### QVideoFrame::PixelFormat QCameraViewfinderSettings::pixelFormat() const

Returns the viewfinder pixel format.

See also setPixelFormat().

### QSize QCameraViewfinderSettings::resolution() const

Returns the viewfinder resolution.

See also setResolution().

### void QCameraViewfinderSettings::setMaximumFrameRate(qreal rate)

Sets the viewfinder maximum frame rate in frames per second.

If the maximum frame rate is equal to the minimum frame rate, the frame rate is fixed. If not, the actual frame rate fluctuates between the minimum and the maximum.

If the given rate equals to `0`, the backend makes an optimal choice based on the supported frame rates and the other viewfinder settings.

See also maximumFrameRate(), setMinimumFrameRate(), and QCamera::supportedViewfinderFrameRateRanges().

### void QCameraViewfinderSettings::setMinimumFrameRate(qreal rate)

Sets the viewfinder minimum frame rate in frames per second.

If the minimum frame rate is equal to the maximum frame rate, the frame rate is fixed. If not, the actual frame rate fluctuates between the minimum and the maximum.

If the given rate equals to `0`, the backend makes an optimal choice based on the supported frame rates and the other viewfinder settings.

See also minimumFrameRate(), setMaximumFrameRate(), and QCamera::supportedViewfinderFrameRateRanges().

### void QCameraViewfinderSettings::setPixelAspectRatio(const QSize &ratio)

Sets the viewfinder pixel aspect ratio.

See also pixelAspectRatio().

### void QCameraViewfinderSettings::setPixelAspectRatio(int horizontal, int vertical)

This is an overloaded function.

Sets the horizontal and vertical elements of the viewfinder's pixel aspect ratio.

### void QCameraViewfinderSettings::setPixelFormat(QVideoFrame::PixelFormat format)

Sets the viewfinder pixel format.

If the given format is equal to QVideoFrame::Format_Invalid, the backend uses the default format.

See also pixelFormat() and QCamera::supportedViewfinderPixelFormats().

### void QCameraViewfinderSettings::setResolution(const QSize &resolution)

Sets the viewfinder resolution.

If the given resolution is empty, the backend makes an optimal choice based on the supported resolutions and the other viewfinder settings.

If the camera is used to capture videos or images, the viewfinder resolution might be ignored if it conflicts with the capture resolution.

See also resolution(), QVideoEncoderSettings::setResolution(), QImageEncoderSettings::setResolution(), and QCamera::supportedViewfinderResolutions().

### void QCameraViewfinderSettings::setResolution(int width, int height)

This is an overloaded function.

Sets the width and height of the viewfinder resolution.

### void QCameraViewfinderSettings::swap(QCameraViewfinderSettings &other)

Swaps this viewfinder settings object with other. This function is very fast and never fails.

### QCameraViewfinderSettings &QCameraViewfinderSettings::operator=(const QCameraViewfinderSettings &other)

Assigns the value of other to a viewfinder settings object.

### QCameraViewfinderSettings &QCameraViewfinderSettings::operator=(QCameraViewfinderSettings &&other)

Moves other to this viewfinder settings object and returns a reference to this object.

## Related Non-Members

### bool operator!=(const QCameraViewfinderSettings &lhs, const QCameraViewfinderSettings &rhs)

Determines if lhs is of equal value to rhs.

Returns true if the settings objects are not of equal value, and false if they are of equal value.

This function was introduced in Qt 5.5.