Qt 5.9 | Qt Multimedia | C++ Classes | QCameraFeedbackControl

Qt 5.9.4 Reference Documentation

# QCameraFeedbackControl Class

The QCameraFeedbackControl class allows controlling feedback (sounds etc) during camera operation More...

Header: | #include <QCameraFeedbackControl>
qmake: | QT += multimedia
Since: | Qt 5.0
Inherits: | QMediaControl

- List of all members, including inherited members

## Public Types

enum | EventType { ViewfinderStarted, ViewfinderStopped, ImageCaptured, ImageSaved, ..., AutoFocusFailed }

## Public Functions

| ~QCameraFeedbackControl()
virtual bool | isEventFeedbackEnabled(EventType event) const = 0
virtual bool | isEventFeedbackLocked(EventType event) const = 0
virtual void | resetEventFeedback(EventType event) = 0
virtual bool | setEventFeedbackEnabled(EventType event, bool enabled) = 0
virtual bool | setEventFeedbackSound(EventType event, const QString &filePath) = 0

## Protected Functions

| QCameraFeedbackControl(QObject *parent = Q_NULLPTR)

## Macros

| QCameraFeedbackControl_iid

## Detailed Description

The QCameraFeedbackControl class allows controlling feedback (sounds etc) during camera operation

When using a camera, there are several times when some form of feedback to the user is given - for example, when an image is taken, or when recording is started. You can enable or disable some of this feedback, or adjust what sound might be played for these actions.

In some cases it may be undesirable to play a sound effect - for example, when initiating video recording the sound itself may be recorded.

Note: In some countries or regions, feedback sounds or other indications (e.g. a red light) are mandatory during camera operation. In these cases, you can check `isEventFeedbackLocked` to check if that type of feedback can be modified. Any attempts to change a locked feedback type will be ignored.

The interface name of QCameraFeedbackControl is `org.qt-project.qt.camerafeedbackcontrol/5.0` as defined in QCameraFeedbackControl_iid.

See also QCamera.

## Member Type Documentation

### enum QCameraFeedbackControl::EventType

This enumeration describes certain events that occur during camera usage. You can associate some form of feedback to be given when the event occurs, or check whether feedback for this event is enabled or locked so that changes cannot be made.

Constant | Value | Description
--- | --- | ---
`QCameraFeedbackControl::ViewfinderStarted` | `1` | The viewfinder stream was started (even if not visible)
`QCameraFeedbackControl::ViewfinderStopped` | `2` | The viewfinder stream was stopped
`QCameraFeedbackControl::ImageCaptured` | `3` | An image was captured but not yet fully processed
`QCameraFeedbackControl::ImageSaved` | `4` | An image is fully available and saved somewhere.
`QCameraFeedbackControl::ImageError` | `5` | An error occurred while capturing an image
`QCameraFeedbackControl::RecordingStarted` | `6` | Video recording has started
`QCameraFeedbackControl::RecordingInProgress` | `7` | Video recording is in progress
`QCameraFeedbackControl::RecordingStopped` | `8` | Video recording has stopped
`QCameraFeedbackControl::AutoFocusInProgress` | `9` | The camera is trying to automatically focus
`QCameraFeedbackControl::AutoFocusLocked` | `10` | The camera has automatically focused successfully
`QCameraFeedbackControl::AutoFocusFailed` | `11` | The camera was unable to focus automatically

## Member Function Documentation

### `[protected]` QCameraFeedbackControl::QCameraFeedbackControl(QObject *parent = Q_NULLPTR)

Constructs a camera feedback control object with parent.

### QCameraFeedbackControl::~QCameraFeedbackControl()

Destroys the camera feedback control object.

### `[pure virtual]` bool QCameraFeedbackControl::isEventFeedbackEnabled(EventType event) const

Returns true if the feedback for event is enabled.

This function was introduced in Qt 5.0.

### `[pure virtual]` bool QCameraFeedbackControl::isEventFeedbackLocked(EventType event) const

Returns true if the feedback setting for event is locked. This may be true because of legal compliance issues, or because configurability of this event's feedback is not supported.

This function was introduced in Qt 5.0.

### `[pure virtual]` void QCameraFeedbackControl::resetEventFeedback(EventType event)

Restores the feedback setting for this event to its default setting.

This function was introduced in Qt 5.0.

### `[pure virtual]` bool QCameraFeedbackControl::setEventFeedbackEnabled(EventType event, bool enabled)

Turns on feedback for the specific event if enabled is true, otherwise disables the feedback. Returns true if the feedback could be modified, or false otherwise (e.g. this feedback type is locked).

This function was introduced in Qt 5.0.

See also isEventFeedbackEnabled().

### `[pure virtual]` bool QCameraFeedbackControl::setEventFeedbackSound(EventType event, const QString &filePath)

When the given event occurs, the sound effect referenced by filePath will be played instead of the default sound.

If this feedback type is locked, or if the supplied path is inaccessible, this function will return false. In addition, some forms of feedback may be non-auditory (e.g. a red light, or a vibration), and false may be returned in this case.

The file referenced should be linear PCM (WAV format).

Note: In the case that a valid file path to an unsupported file is given, this function will return true but the feedback will use the original setting.

This function was introduced in Qt 5.0.

## Macro Documentation

### QCameraFeedbackControl_iid

`org.qt-project.qt.camerafeedbackcontrol/5.0`

Defines the interface name of the QCameraFeedbackControl class.