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wp8.1 没有像wp8一样直接用启动器开启摄像头，他要开启摄像头要借助CaptureElement呈现来自捕获设备（如照相机或网络摄像机）的流。今天讲讲如何打开摄像头，获取焦点，以及拍照。废话不多说，下面直接上代码。当然前提是一定要记住在appxmanifest文件Capabilities选项选择Webcam,不然会报错
首先 XAML代码：
<Grid Name="LayoutRoot">
<CaptureElement x:Name="capturePreview" Stretch="UniformToFill"/>
<Image Name="ProfilePic"></Image>
</Grid>
<StackPanel Grid.Row="1" VerticalAlignment="Bottom">
<Slider x:Name="FocusValueSlider" Maximum="1000" Minimum="0" Grid.Row="0" Margin="12,0,15,0" Header="焦点调节:" ValueChanged="FocusValueSlider_ValueChanged" Value="500" SmallChang e="1" LargeChange="25"></Slider>
<StackPanel Orientation="Horizontal">
<Button Content="启动摄像头" Click="PhotographButton_Click" ></Button>
<Button Margin="50,0,0,0" Content="拍照" Click="CapturePhoto_Click"></Button>
</StackPanel>
</StackPanel>
然后是启动摄像头 事件：
MediaCapture captureManager = null;
async private void PhotographButton_Click(object sender, RoutedEventArgs e)
{
if (captureManager == null)
{
capturePreview.Visibility = Visibility.Visible;
ProfilePic.Visibility = Visibility.Collapsed;
captureManager = new MediaCapture();
//选择后置摄像头
var cameraID = await GetCameraID(Windows.Devices.Enumeration.Panel.Back);
await captureManager.InitializeAsync(new MediaCaptureInitializationSettings
{
StreamingCaptureMode = StreamingCaptureMode.Video,
PhotoCaptureSource = PhotoCaptureSource.Photo,
AudioDeviceId = string.Empty,
VideoDeviceId = cameraID.Id
});
//摄像头旋转90度
captureManager.SetPreviewRotation(VideoRotation.Clockwise90Degrees);
capturePreview.Source = captureManager;
await captureManager.StartPreviewAsync();
}
}
获取后摄像头方法：
private static async Task<DeviceInformation> GetCameraID(Windows.Devices.Enumeration.Panel desired)
{
DeviceInformation deviceID = (await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture))
.FirstOrDefault(x => x.EnclosureLocation != null && x.EnclosureLocation.Panel == desired);
if (deviceID != null) return deviceID;
else throw new Exception(string.Format("Camera of type {0} doesn‘t exist.", desired));
}
接下来是拍照方法：
async private void CapturePhoto_Click(object sender, RoutedEventArgs e)
{
if (captureManager != null)
{
capturePreview.Visibility = Visibility.Collapsed;
ProfilePic.Visibility = Visibility.Visible;
//declare string for filename
string captureFileName = string.Empty;
//图片格式
ImageEncodingProperties format = ImageEncodingProperties.CreateJpeg();
//创建本地存储文件夹
StorageFile file = await ApplicationData.Current.LocalFolder.CreateFileAsync(
"Photo.jpg",
CreationCollisionOption.ReplaceExisting);
await captureManager.CapturePhotoToStorageFileAsync(format, file);
BitmapImage bmpImage = new BitmapImage(new Uri(file.Path));
ProfilePic.Source = bmpImage;
//释放摄像头资源
captureManager.Dispose();
captureManager = null;
}
}
上面已经就完成了 拍照的一般流程，现在讲讲获取焦点，获取焦点的方法：
private void FocusValueSlider_ValueChanged(object sender, RangeBaseValueChangedEventArgs e)
{
try
{
uint focus = Convert.ToUInt32(e.NewValue);
SetFocus(focus);
}
catch
{
}
}
//设置摄像头焦点方法
private async void SetFocus(uint? focusValue = null)
{
try
{
if (!focusValue.HasValue)
{
focusValue = 500;
}
if (captureManager.VideoDeviceController.FocusControl.Supported)
{
captureManager.VideoDeviceController.FlashControl.AssistantLightEnabled = false;
captureManager.VideoDeviceController.FocusControl.Configure(new FocusSettings() { Mode = FocusMode.Manual, Value = focusValue, DisableDriverFallback = true });
await captureManager.VideoDeviceController.FocusControl.FocusAsync();
}
}
catch { }
}
这样就完成了焦点获取。
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原文地址：http://www.cnblogs.com/Terry-King/p/4217221.html
