QScreenCapture 类

此类用于捕获屏幕。 更多...

头：	#include <QScreenCapture>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Multimedia) target_link_libraries(mytarget PRIVATE Qt6::Multimedia)
qmake:	QT += multimedia
Since:	Qt 6.5
在 QML：	ScreenCapture
继承：	QObject

• 所有成员列表，包括继承成员

公共类型

enum	Error { NoError, InternalError, CapturingNotSupported, CaptureFailed, NotFound }

特性

• active : bool
• error : const Error
• errorString : const QString
• screen : QScreen*

公共函数

QMediaCaptureSession *	captureSession () const
QScreenCapture::Error	error () const
QString	errorString () const
bool	isActive () const
QScreen *	screen () const
void	setScreen (QScreen * screen )

公共槽

void	setActive (bool active )
void	start ()
void	stop ()

信号

void	activeChanged (bool)
void	errorChanged ()
void	errorOccurred (QScreenCapture::Error error , const QString & errorString )
void	screenChanged (QScreen *)

详细描述

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();
					

屏幕捕获局限性

On Qt 6.5.2 and above, the following limitations apply to using QScreenCapture:

• It is only supported with the FFmpeg backend.
• On Linux systems using the Wayland compositor, the screen capture implementation is experimental and comes with the following limitations. Due to restrictions of the Wayland protocol, it's impossible to set and get the target screen via the API of the QScreenCapture class. Instead, the OS will show a screen selection wizard upon invoking QScreenCapture::setActive(true) . The screen capture feature requires the installation of the ScreenCast service supported via XDG Desktop Portal and {https://pipewire.org/}{PipeWire} (0.3). These limitations might change in the future.
• It is not supported on mobile operating systems, except on Android. Screen Capture on Android needs additional Android foreground service permission to be added to the AndroidManifest.xml 文件：

  <manifest ...>
  <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
  <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PROJECTION" />
  <application ...>
  <service android:name="org.qtproject.qt.android.multimedia.QtScreenCaptureService"
  android:foregroundServiceType="mediaProjection"
  android:exported="false"/>
  </service>
  </application>
  </manifest>
  							

• 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.
• 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.

另请参阅 QWindowCapture and QMediaCaptureSession .

成员类型文档编制

enum QScreenCapture:: Error

Enumerates error codes that can be signaled by the QScreenCapture 类。 errorString () provides detailed information about the error cause.

常量	值	描述
QScreenCapture::NoError	0	没有错误
QScreenCapture::InternalError	1	内部屏幕捕获驱动程序错误
QScreenCapture::CapturingNotSupported	2	不支持捕获
QScreenCapture::CaptureFailed	4	捕获屏幕失败
QScreenCapture::NotFound	5	找不到选中屏幕

特性文档编制

active : bool

此特性保持捕获目前是否活动。

访问函数：

bool	isActive () const
void	setActive (bool active )

通知程序信号：

void	activeChanged (bool)

[read-only] error : const Error

This property holds the code of the last error.

访问函数：

QScreenCapture::Error

error () const

通知程序信号：

void	errorChanged ()

[read-only] errorString : const QString

This property holds a human readable string describing the cause of error.

访问函数：

QString

errorString () const

通知程序信号：

void	errorChanged ()

screen : QScreen *

此特性保持用于捕获的屏幕。

访问函数：

QScreen *	screen () const
void	setScreen (QScreen * screen )

通知程序信号：

void	screenChanged (QScreen *)

成员函数文档编制

QMediaCaptureSession *QScreenCapture:: captureSession () const

Returns the capture session this QScreenCapture is connected to.

使用 QMediaCaptureSession::setScreenCapture () to connect the camera to a session.

[signal] void QScreenCapture:: errorOccurred ( QScreenCapture::Error error , const QString & errorString )

Signals when an error occurs, along with the errorString .

[slot] void QScreenCapture:: start ()

启动屏幕捕获。

[slot] void QScreenCapture:: stop ()

停止屏幕捕获。

内容

1. 公共类型

2. 特性

3. 公共函数

4. 公共槽

5. 信号

6. 详细描述

7. 屏幕捕获局限性