WPF InkCanvas绘制矩形和椭圆

<Window x:Class=\"WPF_InkCanvas.ROI_InkCanvas\"
     ns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\"
     ns:x=\"http://schemas.microsoft.com/winfx/2006/xaml\"
     ns:d=\"http://schemas.microsoft.com/ /blend/2008\"
     ns:mc=\"http://schemas.open formats.org/markup-compatibility/2006\"
     ns:local=\"clr-namespace:WPF_InkCanvas\"
    mc:Ignorable=\"d\"
     =\"ROI_InkCanvas\" Height=\"450\" Width=\"800\">
  <Grid>
    <Grid.RowDefinitions>
      <RowDefinition/>
      <RowDefinition Height=\"auto\"/>
    </Grid.RowDefinitions>
    <Image Name=\"imgMeasure\" HorizontalAlignment=\"Center\" Stretch=\"Uniform\"/>
    <InkCanvas Name=\"inkCanvasMeasure\" EditingMode=\"None\" Background=\"Transparent\" Strokes=\"{Binding InkStrokes, Mode=TwoWay}\" HorizontalAlignment=\"Center\" 
          Width=\"{Binding ElementName=imgMeasure, Path=ActualWidth}\" Height=\"{Binding ElementName=imgMeasure, Path=ActualHeight}\"
          MouseDown=\"InkCanvasMeasure_MouseDown\" MouseMove=\"InkCanvasMeasure_MouseMove\">
      <Label Content=\"{Binding MeaInfo}\" Background=\"Transparent\" HorizontalAlignment=\"Left\" VerticalAlignment=\"Top\" Margin=\"10\" 
          FontSize=\"18\" Foreground=\"Red\" IsHitTestVisible=\"False\"/>
    </InkCanvas>
    <StackPanel Grid.Row=\"1\" Orientation=\"Horizontal\">
      <Button Content=\"OpenFile\" Margin=\"5\" HorizontalAlignment=\"Left\" FontSize=\"20\" Click=\"OpenFile_Click\"/>
      <ToggleButton Name=\"btnSquare\" Content=\"Draw Square\" Margin=\"5\" HorizontalAlignment=\"Left\" FontSize=\"20\" Click=\"DrawSquare_Click\"/>
      <ToggleButton Name=\"btnEllipse\" Content=\"Draw Ellipse\" Margin=\"5\" HorizontalAlignment=\"Left\" FontSize=\"20\" Click=\"DrawEllipse_Click\"/>
    </StackPanel>
  </Grid>
</Window>

using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
 
namespace WPF_InkCanvas
{
  /// <summary>
  /// ROI_InkCanvas.xaml 的交互逻辑
  /// </summary>
  public partial class ROI_InkCanvas : Window
  {
    private ViewModel viewModel;
    private System.Windows.Point iniP;
    public ROI_InkCanvas()
    {
      InitializeComponent();
 
      DrawingAttributes drawingAttributes = new DrawingAttributes
      {
        Color = Colors.Red,
        Width = 2,
        Height = 2,
        StylusTip = StylusTip.Rectangle,
        //FitToCurve = true,
        IsHighlighter = false,
        IgnorePressure = true,
 
      };
      inkCanvasMeasure.DefaultDrawingAttributes = drawingAttributes;
 
      viewModel = new ViewModel
      {
        MeaInfo = \"测试······\",
        InkStrokes = new StrokeCollection(),
      };
 
      DataContext = viewModel;
    }
 
    private void OpenFile_Click(  sender, RoutedEventArgs e)
    {
      OpenFileDialog openDialog = new OpenFileDialog
      {
        Filter = \"Image Files (*.jpg)|*.jpg|Image Files (*.png)|*.png|Image Files (*.bmp)|*.bmp\",
          = \"Open Image File\"
      };
      if (openDialog.ShowDialog() == true)
      {
        BitmapImage image = new BitmapImage();
        image.BeginInit();
        image.UriSource = new Uri(openDialog.FileName, UriKind.RelativeOrAbsolute);
        image.EndInit();
        imgMeasure.Source = image;
      }
    }
 
    private void DrawSquare_Click(  sender, RoutedEventArgs e)
    {
      if (btnSquare.IsChecked == true)
      {
        btnEllipse.IsChecked = false;
      }
    } 
 
    private void DrawEllipse_Click(  sender, RoutedEventArgs e)
    {
      if (btnEllipse.IsChecked == true)
      {
        btnSquare.IsChecked = false;
      }
    }
 
    private List<System.Windows.Point> GenerateEclipseGeometry(System.Windows.Point st, System.Windows.Point ed)
    {
      double a = 0.5 * (ed.X - st.X);
      double b = 0.5 * (ed.Y - st.Y);
      List<System.Windows.Point> pointList = new List<System.Windows.Point>();
      for (double r = 0; r <= 2 * Math.PI; r = r + 0.01)
      {
        pointList.Add(new System.Windows.Point(0.5 * (st.X + ed.X) + a * Math.Cos(r), 0.5 * (st.Y + ed.Y) + b * Math.Sin(r)));
      }
      return pointList;
    }
    private void InkCanvasMeasure_MouseDown(  sender, MouseButtonEventArgs e)
    {
      if (e.LeftButton == MouseButtonState.Pressed)
      {
        iniP = e.GetPosition(inkCanvasMeasure);
      }
    }
 
    private void InkCanvasMeasure_MouseMove(  sender, MouseEventArgs e)
    {
      if (e.LeftButton == MouseButtonState.Pressed)
      {
        // Draw square
        if (btnSquare.IsChecked == true)
        {
          System.Windows.Point endP = e.GetPosition(inkCanvasMeasure);
          List<System.Windows.Point> pointList = new List<System.Windows.Point>
          {
            new System.Windows.Point(iniP.X, iniP.Y),
            new System.Windows.Point(iniP.X, endP.Y),
            new System.Windows.Point(endP.X, endP.Y),
            new System.Windows.Point(endP.X, iniP.Y),
            new System.Windows.Point(iniP.X, iniP.Y),
          };
          StylusPointCollection point = new StylusPointCollection(pointList);
          Stroke stroke = new Stroke(point)
          {
            DrawingAttributes = inkCanvasMeasure.DefaultDrawingAttributes.Clone()
          };
          viewModel.InkStrokes.Clear();
          viewModel.InkStrokes.Add(stroke);
        }
        // Draw Eclipse
        else if (btnEllipse.IsChecked == true)
        {
          System.Windows.Point endP = e.GetPosition(inkCanvasMeasure);
          List<System.Windows.Point> pointList = GenerateEclipseGeometry(iniP, endP);
          StylusPointCollection point = new StylusPointCollection(pointList);
          Stroke stroke = new Stroke(point)
          {
            DrawingAttributes = inkCanvasMeasure.DefaultDrawingAttributes.Clone()
          };
          viewModel.InkStrokes.Clear();
          viewModel.InkStrokes.Add(stroke);
        }
      }
    }
  }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Ink;
 
namespace WPF_InkCanvas
{
  class ViewModel : INotifyPropertyChanged
  {
    public event PropertyChangedEventHandler PropertyChanged;
 
    protected virtual void  d(string propertyName = null)
    {
      if (PropertyChanged != null)
        PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
 
    private string meaInfo;
    public string MeaInfo
    {
      get => meaInfo;
      set
      {
        meaInfo = value;
         d(\"MeaInfo\");
      }
    }
 
    private StrokeCollection inkStrokes;
    public StrokeCollection InkStrokes
    {
      get { return inkStrokes; }
      set
      {
        inkStrokes = value;
         d(\"InkStrokes\");
      }
    }
  }
}