LowLagPhotoCapture.FinishAsync 方法

定义

命名空间:

Windows.Media.Capture

异步释放捕获照片操作使用的 LowLagPhotoCapture 对象和资源。

public:
 virtual IAsyncAction ^ FinishAsync() = FinishAsync;

/// [Windows.Foundation.Metadata.RemoteAsync]
IAsyncAction FinishAsync();

[Windows.Foundation.Metadata.RemoteAsync]
public IAsyncAction FinishAsync();

function finishAsync()

Public Function FinishAsync () As IAsyncAction

返回

IAsyncAction

用于控制异步操作的对象。

属性

RemoteAsyncAttribute

示例

以下示例演示如何设置和拍摄低延迟照片。 它在 Image 对象中显示捕获的照片和缩略图。 XAML 创建一个包含两个 Image 对象和一些 Button 对象的简单 UI，以便与 MediaCapture 元素交互。 在代码中，有一个用于初始化 MediaCapture 对象的方法、一个初始化 LowLagPhotoCapture 对象的方法、一个用于拍摄照片并显示它的方法，以及一个用于关闭 LowLagPhotoCapture 的方法。

<StackPanel Orientation="Horizontal">
    <Image x:Name="imageLowLagPhoto" Stretch="None" 
           Width="320" Height="240" />
    <Image x:Name="imageLowLagThumbnail" Stretch="None" 
           Width="320" Height="240" />
</StackPanel>

<StackPanel Orientation="Horizontal">
    <Button Click="InitMediaCapture_Click" Content="Initialize Camera" />
    <Button Click="InitLowLagPhotoCapture_Click" Content="Initialize Low Lag Photo Capture"/>
    <Button Click="CaptureLagPhotoCapture_Click" Content="Capture Low Lag Photo"/>
    <Button Click="CloseLagPhotoCapture_Click" Content="Finish low Lag Capture"/>
</StackPanel>

LowLagPhotoCapture lowLagCaptureMgr = null;
MediaCapture mediaCaptureManager;

async private void InitMediaCapture_Click(object sender, RoutedEventArgs e)
{
    mediaCaptureManager = new MediaCapture();
    await mediaCaptureManager.InitializeAsync();
}

async private void InitLowLagPhotoCapture_Click(object sender, RoutedEventArgs e)
{
    // Enable thumbnail images
    mediaCaptureManager.VideoDeviceController.LowLagPhoto.ThumbnailEnabled = true;
    mediaCaptureManager.VideoDeviceController.LowLagPhoto.ThumbnailFormat = MediaThumbnailFormat.Bmp;
    mediaCaptureManager.VideoDeviceController.LowLagPhoto.DesiredThumbnailSize = 25;

    // Image properties
    ImageEncodingProperties imgFormat = ImageEncodingProperties.CreateJpeg();

    // Create LowLagPhotoCapture object
    lowLagCaptureMgr = await mediaCaptureManager.PrepareLowLagPhotoCaptureAsync(imgFormat);
}

async private void CaptureLagPhotoCapture_Click(object sender, RoutedEventArgs e)
{
    // Take photo
    CapturedPhoto photo = await lowLagCaptureMgr.CaptureAsync();

    // Get photo as a BitmapImage
    BitmapImage bitmap = new BitmapImage();
    await bitmap.SetSourceAsync(photo.Frame);

    // Get thumbnail as a BitmapImage
    BitmapImage bitmapThumbnail = new BitmapImage();    
    await bitmapThumbnail.SetSourceAsync(photo.Thumbnail);

    // imageLowLagPhoto is a <Image> object defined in XAML
    imageLowLagPhoto.Source = bitmap;

    // imageLowLagThumbnail is a <Image> object defined in XAML
    imageLowLagThumbnail.Source = bitmapThumbnail;
}

async private void CloseLagPhotoCapture_Click(object sender, RoutedEventArgs e)
{
    // Release the LowLagPhotoCapture object and resources
    await lowLagCaptureMgr.FinishAsync();
}