QScreenCapture Class▲
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Header: QScreenCapture
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Since: Qt 6.5
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CMake:
find_package(Qt6 REQUIRED COMPONENTS Multimedia)
target_link_libraries(mytarget PRIVATE Qt6::Multimedia)
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qmake: QT += multimedia
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Inherited By:
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Instantiated By: qml-qtmultimedia-screencapture.xml
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Inherits: QObject
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Inherited By:
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Group: QScreenCapture is part of multimedia, multimedia_video
Detailed Description▲
The class captures a screen. It is managed by the QMediaCaptureSession class where the captured screen can be displayed in a video preview object or recorded to a file.
QMediaCaptureSession session;
QAudioInput audioInput;
session.setAudioInput(&input);
QMediaRecorder recorder;
session.setRecorder(&recorder);
recorder.setQuality(QMediaRecorder::HighQuality);
recorder.setOutputLocation(QUrl::fromLocalFile("test.mp3"));
recorder.record();Screen Capture Limitations▲
On Qt 6.5.2 and above, the following limitations apply to using QScreenCapture:
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It is only supported with the FFmpeg backend.
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It is unsupported on Linux with Wayland compositor, due to Wayland protocol restrictions and limitations.
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It is not supported on mobile operating systems, except on Android. There, you might run into performance issues as the class is currently implemented via QScreen::grabWindow, which is not optimal for the use case.
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On embedded with EGLFS, it has limited functionality. For Qt Quick applications, the class is currently implemented via QQuickWindow::grabWindow, which can cause performance issues.
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In most cases, we set a screen capture frame rate that equals the screen refresh rate, except on Windows, where the rate might be flexible. Such a frame rate (75/120 FPS) might cause performance issues on weak CPUs if the captured screen is of 4K resolution. On EGLFS, the capture frame rate is currently locked to 30 FPS.
See Also▲
See also QWindowCapture, QMediaCaptureSession
Member Type Documentation▲
enum QScreenCapture::Error▲
Enumerates error codes that can be signaled by the QScreenCapture class. errorString() provides detailed information about the error cause.
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Constant |
Value |
Description |
|---|---|---|
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QScreenCapture::NoError |
0 |
No error |
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QScreenCapture::InternalError |
1 |
Internal screen capturing driver error |
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QScreenCapture::CapturingNotSupported |
2 |
Capturing is not supported |
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QScreenCapture::CaptureFailed |
4 |
Capturing screen failed |
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QScreenCapture::NotFound |
5 |
Selected screen not found |
Property Documentation▲
active : bool▲
This property holds whether the capturing is currently active.
Access functions:
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bool isActive() const
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void setActive(bool active)
Notifier signal:
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void activeChanged(bool)
[read-only] error : const Error▲
This property holds the code of the last error.
Access functions:
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error() const
Notifier signal:
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void errorChanged()
[read-only] errorString : const QString▲
This property holds a human readable string describing the cause of error.
Access functions:
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errorString() const
Notifier signal:
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void errorChanged()
screen : QScreen*▲
This property holds the screen for capturing.
Access functions:
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*screen() const
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void setScreen( *screen)
Notifier signal:
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void screenChanged(QScreen *)
Member Function Documentation▲
QMediaCaptureSession *QScreenCapture::captureSession() const▲
Returns the capture session this QScreenCapture is connected to.
Use QMediaCaptureSession::setScreenCapture() to connect the camera to a session.
void QScreenCapture::errorOccurred(QScreenCapture::Error error, const QString &errorString)▲
Signals when an error occurs, along with the errorString.
void QScreenCapture::start()▲
Starts screen capture.
void QScreenCapture::stop()▲
Stops screen capture.