WPF 展示视频修改为WriteableBitmap

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接着上一篇，进行WriteableBitmap性能优化

修改后运行对比如下：

前（CPU与内存不稳定）：

后：

使用NuGet如下：

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代码如下

一、创建MainWindow.xaml代码如下。

<ws:Window x:Class="OpenCVSharpExample.MainWindow"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:ws="https://github.com/WPFDevelopersOrg.WPFDevelopers.Minimal"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:local="clr-namespace:OpenCVSharpExample"Icon="OpenCV_Logo.png"mc:Ignorable="d" WindowStartupLocation="CenterScreen"Title="OpenCVSharpExample https://github.com/WPFDevelopersOrg" Height="450" Width="800"><Grid Margin="4"><Grid.ColumnDefinitions><ColumnDefinition/><ColumnDefinition Width="Auto"/></Grid.ColumnDefinitions><Image Grid.Row="0" Name="imgViewport"/><GroupBox Header="Operation" Grid.Column="1" Margin="0,0,4,0"><Grid><Grid.RowDefinitions><RowDefinition/><RowDefinition/><RowDefinition Height="Auto"/></Grid.RowDefinitions><StackPanel Grid.Row="0" HorizontalAlignment="Center"><CheckBox IsChecked="{Binding IsSave,RelativeSource={RelativeSource AncestorType=local:MainWindow}}"VerticalAlignment="Center" Content="Save" Margin="0,4"/><ComboBox Name="ComboBoxCamera" ItemsSource="{Binding CameraArray,RelativeSource={RelativeSource AncestorType=local:MainWindow}}" SelectedIndex="{Binding CameraIndex,RelativeSource={RelativeSource AncestorType=local:MainWindow}}"SelectionChanged="ComboBoxCamera_SelectionChanged"/></StackPanel><StackPanel Orientation="Horizontal" Grid.Row="2" HorizontalAlignment="Center"><Button Name="btPlay" Content="Play" Style="{StaticResource PrimaryButton}" Click="btPlay_Click" IsEnabled="False"/><Button Name="btStop" Click="btStop_Click" Content="Stop" Margin="4,0"/></StackPanel></Grid></GroupBox></Grid>
</ws:Window>

二、MainWindow.xaml.cs代码如下。

using OpenCvSharp;
using OpenCvSharp.Extensions;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Management;
using System.Threading;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media.Imaging;
using System.Windows.Threading;namespace OpenCVSharpExample
{/// <summary>/// MainWindow.xaml 的交互逻辑/// </summary>public partial class MainWindow{private VideoCapture capCamera;private VideoWriter videoWriter;private Mat matImage = new Mat();private Thread cameraThread;private Thread writerThread;private CascadeClassifier haarCascade;private WriteableBitmap writeableBitmap;private Rectangle rectangle;public List<string> CameraArray{get { return (List<string>)GetValue(CameraArrayProperty); }set { SetValue(CameraArrayProperty, value); }}public static readonly DependencyProperty CameraArrayProperty =DependencyProperty.Register("CameraArray", typeof(List<string>), typeof(MainWindow), new PropertyMetadata(null));public int CameraIndex{get { return (int)GetValue(CameraIndexProperty); }set { SetValue(CameraIndexProperty, value); }}public static readonly DependencyProperty CameraIndexProperty =DependencyProperty.Register("CameraIndex", typeof(int), typeof(MainWindow), new PropertyMetadata(0));public bool IsSave{get { return (bool)GetValue(IsSaveProperty); }set { SetValue(IsSaveProperty, value); }}public static readonly DependencyProperty IsSaveProperty =DependencyProperty.Register("IsSave", typeof(bool), typeof(MainWindow), new UIPropertyMetadata(IsSaveChanged));private static void IsSaveChanged(DependencyObject d, DependencyPropertyChangedEventArgs e){var mainWindow = d as MainWindow;if (e.NewValue != null){var save = (bool) e.NewValue;if (save)mainWindow.StartRecording();elsemainWindow.StopRecording();}}public MainWindow(){InitializeComponent();Width = SystemParameters.WorkArea.Width / 1.5;Height = SystemParameters.WorkArea.Height / 1.5;this.Loaded += MainWindow_Loaded;}private void MainWindow_Loaded(object sender, RoutedEventArgs e){InitializeCamera();}private void ComboBoxCamera_SelectionChanged(object sender, SelectionChangedEventArgs e){if (CameraArray.Count - 1 < CameraIndex)return;if (capCamera != null && cameraThread != null){cameraThread.Abort();StopDispose();}CreateCamera();writeableBitmap = new WriteableBitmap(capCamera.FrameWidth, capCamera.FrameHeight, 0, 0, System.Windows.Media.PixelFormats.Bgra32, null);imgViewport.Source = writeableBitmap;}private void InitializeCamera(){CameraArray = GetAllConnectedCameras();}List<string> GetAllConnectedCameras(){var cameraNames = new List<string>();using (var searcher = new ManagementObjectSearcher("SELECT * FROM Win32_PnPEntity WHERE (PNPClass = 'Image' OR PNPClass = 'Camera')")){foreach (var device in searcher.Get()){cameraNames.Add(device["Caption"].ToString());}}return cameraNames;}void CreateCamera(){capCamera = new VideoCapture(CameraIndex);capCamera.Fps = 30;cameraThread = new Thread(PlayCamera);cameraThread.Start();}private void PlayCamera(){while (capCamera != null && !capCamera.IsDisposed){capCamera.Read(matImage);if (matImage.Empty()) break;//Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() =>//{//    var converted = Convert(BitmapConverter.ToBitmap(matImage));//    imgViewport.Source = converted;//}));using (var img = BitmapConverter.ToBitmap(matImage)){var now = DateTime.Now;var g = Graphics.FromImage(img);var brush = new SolidBrush(System.Drawing.Color.Red);g.DrawString($"北京时间：{ now.ToString("yyyy年MM月dd日 HH:mm:ss")}", new System.Drawing.Font("Arial", 18), brush, new PointF(5, 5));rectangle = new Rectangle(0, 0, img.Width, img.Height);brush.Dispose();g.Dispose();Dispatcher.Invoke(new Action(() =>{WriteableBitmapHelper.BitmapCopyToWriteableBitmap(img, writeableBitmap, rectangle, 0, 0, System.Drawing.Imaging.PixelFormat.Format32bppArgb);}));};Thread.Sleep(100);}}private void StartRecording(){if (capCamera == null){WPFDevelopers.Minimal.Controls.MessageBox.Show("未开启摄像机","提示",MessageBoxButton.OKCancel,MessageBoxImage.Error);return;}var videoFile = System.IO.Path.Combine(System.Environment.CurrentDirectory, "Video");if (!System.IO.Directory.Exists(videoFile))System.IO.Directory.CreateDirectory(videoFile);var currentTime = System.IO.Path.Combine(videoFile, $"{DateTime.Now.ToString("yyyyMMddHHmmsshh")}.avi");videoWriter = new VideoWriter(currentTime, FourCCValues.XVID, capCamera.Fps, new OpenCvSharp.Size(capCamera.FrameWidth, capCamera.FrameHeight));writerThread = new Thread(AddCameraFrameToRecording);writerThread.Start();}private void StopRecording(){if (videoWriter != null && !videoWriter.IsDisposed){videoWriter.Release();videoWriter.Dispose();videoWriter = null;}}private void AddCameraFrameToRecording(){var waitTimeBetweenFrames = 1_000 / capCamera.Fps;var lastWrite = DateTime.Now;while (!videoWriter.IsDisposed){if (DateTime.Now.Subtract(lastWrite).TotalMilliseconds < waitTimeBetweenFrames)continue;lastWrite = DateTime.Now;videoWriter.Write(matImage);}}private void btStop_Click(object sender, RoutedEventArgs e){StopDispose();btStop.IsEnabled = false;}void StopDispose(){if (capCamera != null && capCamera.IsOpened()){capCamera.Dispose();capCamera = null;}if (videoWriter != null && !videoWriter.IsDisposed){videoWriter.Release();videoWriter.Dispose();videoWriter = null;}btPlay.IsEnabled = true;GC.Collect();}void CreateRecord(){cameraThread = new Thread(PlayCamera);cameraThread.Start();}BitmapImage Convert(Bitmap src){System.Drawing.Image img = src;var now = DateTime.Now;var g = Graphics.FromImage(img);var brush = new SolidBrush(System.Drawing.Color.Red);g.DrawString($"北京时间：{ now.ToString("yyyy年MM月dd日 HH:mm:ss")}", new System.Drawing.Font("Arial", 18), brush, new PointF(5, 5));brush.Dispose();g.Dispose();var writeableBitmap = WriteableBitmapHelper.BitmapToWriteableBitmap(src);return WriteableBitmapHelper.ConvertWriteableBitmapToBitmapImage(writeableBitmap);}protected override void OnClosing(CancelEventArgs e){if(WPFDevelopers.Minimal.Controls.MessageBox.Show("是否关闭系统?", "询问", MessageBoxButton.OKCancel, MessageBoxImage.Question) != MessageBoxResult.OK) {e.Cancel = true;return;}}protected override void OnClosed(EventArgs e){StopDispose();}private void btPlay_Click(object sender, RoutedEventArgs e){btPlay.IsEnabled = false;btStop.IsEnabled = true;CreateCamera();}}
}

三、WriteableBitmapHelper.cs代码如下。

using System.IO;
using System.Windows;
using System.Windows.Media.Imaging;namespace OpenCVSharpExample
{public class WriteableBitmapHelper{//将Bitmap 转换成WriteableBitmap public static WriteableBitmap BitmapToWriteableBitmap(System.Drawing.Bitmap src){var wb = CreateCompatibleWriteableBitmap(src);System.Drawing.Imaging.PixelFormat format = src.PixelFormat;if (wb == null){wb = new WriteableBitmap(src.Width, src.Height, 0, 0, System.Windows.Media.PixelFormats.Bgra32, null);format = System.Drawing.Imaging.PixelFormat.Format32bppArgb;}BitmapCopyToWriteableBitmap(src, wb, new System.Drawing.Rectangle(0, 0, src.Width, src.Height), 0, 0, format);return wb;}//创建尺寸和格式与Bitmap兼容的WriteableBitmappublic static WriteableBitmap CreateCompatibleWriteableBitmap(System.Drawing.Bitmap src){System.Windows.Media.PixelFormat format;switch (src.PixelFormat){case System.Drawing.Imaging.PixelFormat.Format16bppRgb555:format = System.Windows.Media.PixelFormats.Bgr555;break;case System.Drawing.Imaging.PixelFormat.Format16bppRgb565:format = System.Windows.Media.PixelFormats.Bgr565;break;case System.Drawing.Imaging.PixelFormat.Format24bppRgb:format = System.Windows.Media.PixelFormats.Bgr24;break;case System.Drawing.Imaging.PixelFormat.Format32bppRgb:format = System.Windows.Media.PixelFormats.Bgr32;break;case System.Drawing.Imaging.PixelFormat.Format32bppPArgb:format = System.Windows.Media.PixelFormats.Pbgra32;break;case System.Drawing.Imaging.PixelFormat.Format32bppArgb:format = System.Windows.Media.PixelFormats.Bgra32;break;default:return null;}return new WriteableBitmap(src.Width, src.Height, 0, 0, format, null);}//将Bitmap数据写入WriteableBitmap中public static void BitmapCopyToWriteableBitmap(System.Drawing.Bitmap src, WriteableBitmap dst, System.Drawing.Rectangle srcRect, int destinationX, int destinationY, System.Drawing.Imaging.PixelFormat srcPixelFormat){var data = src.LockBits(new System.Drawing.Rectangle(new System.Drawing.Point(0, 0), src.Size), System.Drawing.Imaging.ImageLockMode.ReadOnly, srcPixelFormat);dst.WritePixels(new Int32Rect(srcRect.X, srcRect.Y, srcRect.Width, srcRect.Height), data.Scan0, data.Height * data.Stride, data.Stride, destinationX, destinationY);src.UnlockBits(data);}public static BitmapImage ConvertWriteableBitmapToBitmapImage(WriteableBitmap wbm){BitmapImage bmImage = new BitmapImage();using (MemoryStream stream = new MemoryStream()){PngBitmapEncoder encoder = new PngBitmapEncoder();encoder.Frames.Add(BitmapFrame.Create(wbm));encoder.Save(stream);bmImage.BeginInit();bmImage.CacheOption = BitmapCacheOption.OnLoad;bmImage.StreamSource = stream;bmImage.EndInit();bmImage.Freeze();}return bmImage;}}
}

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效果预览