如何用MediaCapture解决二维码扫描问题

二维码扫描的实现，简单的来说可以分三步走：“成像”、“截图”与“识别”。

UWP开发中，最常用的媒体工具非MediaCapture莫属了，下面就来简单介绍一下如何利用MediaCapture来实现扫描和截图并且利用Zxing识别二维码，以及会遇到的问题和需要注意的地方。

1. 初始化与成像

 1 private async void InitMediaCaptureAsync() 2     { 3       //寻找后置摄像头 4       var allVideoDevices = await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture); 5       var cameraDevice = allVideoDevices.FirstOrDefault(x => x.EnclosureLocation != null && x.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Back); 6  7       if (cameraDevice == null) 8       { 9         Debug.WriteLine("No camera device found!");10 11         return;12       }13 14       var settings = new MediaCaptureInitializationSettings15       {16         StreamingCaptureMode = StreamingCaptureMode.Video,17         //必须，否则截图的时候会很卡很慢18         PhotoCaptureSource = PhotoCaptureSource.VideoPreview,19         VideoDeviceId = cameraDevice.Id20       };21 22       _mediaCapture = new MediaCapture();23 24       try25       {26         await _mediaCapture.InitializeAsync(settings);27         _initialized = true;//初始化成功28       }29       catch (UnauthorizedAccessException)30       {31         Debug.WriteLine("The app was denied access to the camera");32       }33       catch (Exception ex)34       {35         Debug.WriteLine("Exception when initializing MediaCapture with {0}: {1}", cameraDevice.Id, ex.ToString());36       }37 38       if (_initialized)39       {40         var focusControl = _mediaCapture.VideoDeviceController.FocusControl;41 42         if (focusControl.Supported)43         {44           var focusSettings = new FocusSettings()45           {46             Mode = focusControl.SupportedFocusModes.FirstOrDefault(f => f == FocusMode.Continuous),47             DisableDriverFallback = true,48             AutoFocusRange = focusControl.SupportedFocusRanges.FirstOrDefault(f => f == AutoFocusRange.FullRange),49             Distance = focusControl.SupportedFocusDistances.FirstOrDefault(f => f == ManualFocusDistance.Nearest)50           };51 52           //设置聚焦，最好使用FocusMode.Continuous，否则影响截图会很模糊，不利于识别53           focusControl.Configure(focusSettings);54         }55 56         captureElement.Source = _mediaCapture;57         captureElement.FlowDirection = FlowDirection.LeftToRight;58 59         try60         {61           await _mediaCapture.StartPreviewAsync();62           _previeget='_blank'>wing = true;63         }64         catch (Exception ex)65         {66           Debug.WriteLine("Exception when starting the preview: {0}", ex.ToString());67         }68 69         if (_previewing)70         {71           try72           {73             if (_mediaCapture.VideoDeviceController.FlashControl.Supported)74             {75               //关闭闪光灯76               _mediaCapture.VideoDeviceController.FlashControl.Enabled = false;77             }78           }79           catch80           {81           }82 83           if (focusControl.Supported)84           {85             //开始聚焦86             await focusControl.FocusAsync();87           }88         }89       }90     }

海外公司注册、海外银行开户、跨境平台代入驻、VAT、EPR等知识和在线办理：https://www.xlkjsw.com

原标题：如何用MediaCapture解决二维码扫描问题

关键词：