内容

• 特性
• 信号
• 方法
• 详细描述

CameraCapture QML Type

捕获摄像头图像的接口 更多...

导入语句：

import QtMultimedia 5.8

• 所有成员列表，包括继承成员

特性

• capturedImagePath : string
• errorString : string
• ready : bool
• resolution : size
• supportedResolutions : list<size>

信号

• captureFailed ( requestId , message )
• imageCaptured ( requestId , preview )
• imageMetadataAvailable ( requestId , key , value )
• imageSaved ( requestId , path )

方法

• cancelCapture ()
• capture ()
• captureToLocation ( location )
• setMetadata ( key , value )

详细描述

This type allows you to capture still images and be notified when they are available or saved to disk. You can adjust the resolution of the captured image and where the saved image should go.

CameraCapture is a child of a Camera (as the imageCapture property) and cannot be created directly.

Item {
    width: 640
    height: 360
    Camera {
        id: camera
        imageCapture {
            onImageCaptured: {
                // Show the preview in an Image
                photoPreview.source = preview
            }
        }
    }
    VideoOutput {
        source: camera
        focus : visible // to receive focus and capture key events when visible
        anchors.fill: parent
        MouseArea {
            anchors.fill: parent;
            onClicked: camera.imageCapture.capture();
        }
    }
    Image {
        id: photoPreview
    }
}
					

特性文档编制

capturedImagePath : string

This property holds the location of the last captured image.

errorString : string

This property holds the error message related to the last capture.

ready : bool

This property holds a bool value indicating whether the camera is ready to capture photos or not.

调用 capture() while ready is false is not permitted and results in an error.

resolution : size

This property holds the resolution/size of the image to be captured. If empty, the system chooses the appropriate resolution.

另请参阅 supportedResolutions .

supportedResolutions : list < size >

This property holds a list of resolutions which are supported for capturing. The information can be used to set a valid resolution . If the camera isn't loaded, the list will be empty.

This QML property was introduced in Qt 5.9.

另请参阅 resolution .

信号文档编制

captureFailed ( requestId , message )

This signal is emitted when an error occurs during capture with requestId . A descriptive message is available in message .

相应处理程序是 onCaptureFailed .

imageCaptured ( requestId , preview )

This signal is emitted when an image with requestId has been captured but not yet saved to the filesystem. The preview parameter can be used as the URL supplied to an 图像 .

相应处理程序是 onImageCaptured .

另请参阅 imageSaved .

imageMetadataAvailable ( requestId , key , value )

This signal is emitted when the image with requestId has new metadata available with the key key and value value .

相应处理程序是 onImageMetadataAvailable .

另请参阅 imageCaptured .

imageSaved ( requestId , path )

This signal is emitted after the image with requestId has been written to the filesystem. The path is a local file path, not a URL.

相应处理程序是 onImageSaved .

另请参阅 imageCaptured .

方法文档编制

cancelCapture ()

Cancel pending image capture requests.

capture ()

开始图像捕获。 imageCaptured and imageSaved signals will be emitted when the capture is complete.

The image will be captured to the default system location, typically QStandardPaths::writableLocation ( QStandardPaths::PicturesLocation ) for still imaged or QStandardPaths::writableLocation ( QStandardPaths::MoviesLocation ) for video.

Camera saves all the capture parameters like exposure settings or image processing parameters, so changes to camera parameters after capture() is called do not affect previous capture requests.

capture() returns the capture requestId parameter, used with imageExposed(), imageCaptured() , imageMetadataAvailable() and imageSaved() signals.

另请参阅 ready .

captureToLocation ( location )

Start image capture to specified location 。 imageCaptured and imageSaved signals will be emitted when the capture is complete.

CameraCapture::captureToLocation returns the capture requestId parameter, used with imageExposed(), imageCaptured() , imageMetadataAvailable() and imageSaved() signals.

If the application is unable to write to the location specified by location the CameraCapture will emit an error. The most likely reasons for the application to be unable to write to a location is that the path is wrong and the location does not exists, or the application does not have write permission for that location.

setMetadata ( key , value )

Sets a particular metadata key to value for the subsequent image captures.

另请参阅 QMediaMetaData .