可以使用Windows.Phone.Media.Capture.PhotoCaptureDevice 进行高像素图片的捕获（需要自己画视图界面，因为该平台的PhotoChooserTask API 不支持捕获高像素的功能），并且需要使用预定义像素分辨率手动设置捕获的像素。需要注意的额外的像素是没有从 PhotoCaptureDevice 类的获取手机支持分辨率的静态方法 IReadOnlyList<Size> GetAvailabeCaptureResolutions() 方法中检索到的。还有就是为了让 PhotoCaptureDevice 正常工作ID_CAP_ISV_CAMERA功能声明需要添加到清单文件WMAppManifest.xml
下面是可以手动获取的支持高分辨率的设备型号
| 手机型号 | 变体 | 手动配置高像素的选项 |
|---|---|---|
| Lumia 1020 | RM-875, RM-876, RM-877 | 7712x4352 (16:9), 7136x5360 (4:3) |
| Lumia 1520 | RM-937, RM-938, RM-939 | 5376x3024 (16:9), 4992x3744 (4:3) |
为高像素拍摄初始化相机
下面的示例代码演示你如何在应用中创建简单的取景器，并且初始化高像素 photo capture。下面
的代码是使用 VideoBrush 作为 canvas 的背景：
<!-- Simple viewfinder page --> <phone:PhoneApplicationPage x:Class="ViewfinderPage" ... > <Grid x:Name="LayoutRoot" Background="Transparent"> <Grid x:Name="ContentPanel"> <Canvas x:Name="Canvas" ... > <Canvas.Background> <VideoBrush x:Name="ViewfinderVideoBrush" Stretch="Uniform"/> </Canvas.Background> </Canvas> </Grid> </Grid> </phone:PhoneApplicationPage>
在相应的 C# 页面，向以往相同，先初始化 PhotoCaptureDevice，这里需要添加额外的代码检测
设备的型号，从而根据条件进行选择，并且在 IAsyncOperation<PhotoCaptureDevice> OpenAsync(CameraSensorLocation senor, Size initialRsolution) 方法中初始化高分辨率的尺寸。需要注意的是你只能每次使用一种分辨率捕获一张照片，所以如果你需要高像素的版本和低像素
的版本的图片，你可以先捕获一张高像素照片，然后对它进行操作，比如使用 Nokia Imaging SDK 对它进行压缩
尺寸来获得另一个版本的图片。
using Microsoft.Devices; using Windows.Phone.Media.Capture; ... public partial class ViewfinderPage : PhoneApplicationPage { private const CameraSensorLocation SENSOR_LOCATION = CameraSensorLocation.Back; private PhotoCaptureDevice _device = null; private bool _focusing = false; private bool _capturing = false; ... ~ViewfinderPage() { if (_device != null) { UninitializeCamera(); } } protected override void OnNavigatedTo(NavigationEventArgs e) { base.OnNavigatedTo(e); if (_device == null) { InitializeCamera(); } } protected override void OnNavigatingFrom(NavigatingCancelEventArgs e) { if ((_focusing || _capturing) && e.IsCancelable) { e.Cancel = true; } base.OnNavigatingFrom(e); } protected override void OnNavigatedFrom(NavigationEventArgs e) { base.OnNavigatedFrom(e); if (_device != null) { UninitializeCamera(); } } /// <summary> /// Synchronously initialises the photo capture device for a high resolution photo capture. /// Viewfinder video stream is sent to a VideoBrush element called ViewfinderVideoBrush, and /// device hardware capture key is wired to the CameraButtons_ShutterKeyHalfPressed and /// CameraButtons_ShutterKeyPressed methods. /// </summary> private void InitializeCamera() { Windows.Foundation.Size captureResolution; var deviceName = DeviceStatus.DeviceName; if (deviceName.Contains("RM-875") || deviceName.Contains("RM-876") || deviceName.Contains("RM-877")) { captureResolution = new Windows.Foundation.Size(7712, 4352); // 16:9 ratio //captureResolution = new Windows.Foundation.Size(7136, 5360); // 4:3 ratio } else if (deviceName.Contains("RM-937") || deviceName.Contains("RM-938") || deviceName.Contains("RM-939")) { captureResolution = new Windows.Foundation.Size(5376, 3024); // 16:9 ratio //captureResolution = new Windows.Foundation.Size(4992, 3744); // 4:3 ratio } else { captureResolution = PhotoCaptureDevice.GetAvailableCaptureResolutions(SENSOR_LOCATION).First(); } var task = PhotoCaptureDevice.OpenAsync(SENSOR_LOCATION, captureResolution).AsTask(); task.Wait(); _device = task.Result; ViewfinderVideoBrush.SetSource(_device); if (PhotoCaptureDevice.IsFocusSupported(SENSOR_LOCATION)) { Microsoft.Devices.CameraButtons.ShutterKeyHalfPressed += CameraButtons_ShutterKeyHalfPressed; } Microsoft.Devices.CameraButtons.ShutterKeyPressed += CameraButtons_ShutterKeyPressed; ... } /// <summary> /// Uninitialises the photo capture device and unwires the device hardware capture keys. /// </summary> private void UninitializeCamera() { if (PhotoCaptureDevice.IsFocusSupported(SENSOR_LOCATION)) { Microsoft.Devices.CameraButtons.ShutterKeyHalfPressed -= CameraButtons_ShutterKeyHalfPressed; } Microsoft.Devices.CameraButtons.ShutterKeyPressed -= CameraButtons_ShutterKeyPressed; _device.Dispose(); _device = null; } ... }
拍摄
现在设备的相机已经初始化完成了，设备的拍照按键可以是相机进行自动对焦，并且捕获一张高像素照片
... public partial class ViewfinderPage : PhoneApplicationPage { ... /// <summary> /// Asynchronously autofocuses the photo capture device. /// </summary> private async void CameraButtons_ShutterKeyHalfPressed(object sender, EventArgs e) { if (!_focusing && !_capturing) { _focusing = true; await _device.FocusAsync(); _focusing = false; } } /// <summary> /// Asynchronously captures a frame for further usage. /// </summary> private async void CameraButtons_ShutterKeyPressed(object sender, EventArgs e) { if (!_focusing && !_capturing) { _capturing = true; var stream = new MemoryStream(); try { var sequence = _device.CreateCaptureSequence(1); sequence.Frames[0].CaptureStream = stream.AsOutputStream(); await _device.PrepareCaptureSequenceAsync(sequence); await sequence.StartCaptureAsync(); } catch (Exception ex) { stream.Close(); } _capturing = false; if (stream.CanRead) { // We now have the captured image JPEG data in variable "stream" for further usage } } } ... }
获得一个全功能的“单击画面对焦”、“在捕获时冻结预览”，可以参考示例代码 Photo Inspector
Nokia WiKi 原文链接：http://developer.nokia.com/Resources/Library/Lumia/#!imaging/working-with-high-resolution-photos/capturing-high-resolution-photos.html