<Window x:Class="WPF_InkCanvas.ROI_InkCanvas"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"    xmlns:local="clr-namespace:WPF_InkCanvas"    mc:Ignorable="d"  <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 的交互邏輯  /// </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 = "測試······",        InkStrokes = new StrokeCollection(),      };       DataContext = viewModel;    }     private void OpenFile_Click(object sender, RoutedEventArgs e)    {      OpenFileDialog openDialog = new OpenFileDialog      {        Filter = "Image Files (*.jpg)|*.jpg|Image Files (*.png)|*.png|Image Files (*.bmp)|*.bmp",      };      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(object sender, RoutedEventArgs e)    {      if (btnSquare.IsChecked == true)      {        btnEllipse.IsChecked = false;      }    }      private void DrawEllipse_Click(object 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(object sender, MouseButtonEventArgs e)    {      if (e.LeftButton == MouseButtonState.Pressed)      {        iniP = e.GetPosition(inkCanvasMeasure);      }    }     private void InkCanvasMeasure_MouseMove(object 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 OnPropertyChanged(string propertyName = null)    {      if (PropertyChanged != null)        PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));    }     private string meaInfo;    public string MeaInfo    {      get => meaInfo;      set      {        meaInfo = value;        OnPropertyChanged("MeaInfo");      }    }     private StrokeCollection inkStrokes;    public StrokeCollection InkStrokes    {      get { return inkStrokes; }      set      {        inkStrokes = value;        OnPropertyChanged("InkStrokes");      }    }  }}