WPF InkCanvas基本操作方法详解

WPF的InkCanvas就是一个画板，可以在上面随意涂鸦，每写上一笔，InkCanvas的Strokes集合里就新增一个涂鸦对象，下面的代码演示了基本的操作。

效果图

xaml代码

<Window x:Class="WPF_InkCanvas.MainWindow"
    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"
    Title="MainWindow" Height="450" Width="800">
  <Grid>
    <Grid.RowDefinitions>
      <RowDefinition/>
      <RowDefinition Height="auto"/>
      <RowDefinition Height="auto"/>
    </Grid.RowDefinitions>
    <Image Name="imgMeasure" HorizontalAlignment="Center" Stretch="Uniform"/>
    <InkCanvas Name="inkCanvasMeasure" EditingMode="None" Background="Transparent" 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>
    <Grid Grid.Row="1">
      <Grid.ColumnDefinitions>
        <ColumnDefinition/>
        <ColumnDefinition/>
        <ColumnDefinition/>
        <ColumnDefinition/>
        <ColumnDefinition/>
      </Grid.ColumnDefinitions>
      <RadioButton Grid.Column="0" Content="绘制墨迹" Click="RadioButton_Click"/>
      <RadioButton Grid.Column="1" Content="按点擦除" Click="RadioButton_Click"/>
      <RadioButton Grid.Column="2" Content="按线擦除" Click="RadioButton_Click"/>
      <RadioButton Grid.Column="3" Content="选中墨迹" Click="RadioButton_Click"/>
      <RadioButton Grid.Column="4" Content="停止操作" Click="RadioButton_Click"/>
    </Grid>
    <StackPanel Grid.Row="2" Orientation="Horizontal">
      <Button Content="OpenFile" Margin="5" HorizontalAlignment="Left" FontSize="20" Click="OpenFile_Click"/>
      <Button Content="SaveInkCanvas" Margin="5" HorizontalAlignment="Left" FontSize="20" Click="SaveInkCanvas_Click"/>
      <Button Content="LoadInkCanvas" Margin="5" HorizontalAlignment="Left" FontSize="20" Click="LoadInkCanvas_Click"/>
      <Button Content="CopyInkCanvas" Margin="5" HorizontalAlignment="Left" FontSize="20" Click="CopyInkCanvas_Click"/>
      <Button Content="PasteInkCanvas" Margin="5" HorizontalAlignment="Left" FontSize="20" Click="PasteInkCanvas_Click"/>
    </StackPanel>
  </Grid>
</Window>

后台代码

using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.IO;
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.Navigation;
using System.Windows.Shapes;

namespace WPF_InkCanvas
{
  /// <summary>
  /// MainWindow.xaml 的交互逻辑
  /// </summary>
  public partial class MainWindow : Window
  {
    ViewModel viewModel;
    public MainWindow()
    {
      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······",
      };

      DataContext = viewModel;
    }

    private void InkCanvasMeasure_MouseDown(object sender, MouseButtonEventArgs e)
    {

    }

    private void InkCanvasMeasure_MouseMove(object sender, MouseEventArgs e)
    {

    }

    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",
        Title = "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 RadioButton_Click(object sender, RoutedEventArgs e)
    {
      if ((sender as RadioButton).Content.ToString() == "绘制墨迹")
      {
        inkCanvasMeasure.EditingMode = InkCanvasEditingMode.Ink;
      }

      else if ((sender as RadioButton).Content.ToString() == "按点擦除")
      {
        inkCanvasMeasure.EditingMode = InkCanvasEditingMode.EraseByPoint;
      }

      else if ((sender as RadioButton).Content.ToString() == "按线擦除")
      {
        inkCanvasMeasure.EditingMode = InkCanvasEditingMode.EraseByStroke;
      }

      else if ((sender as RadioButton).Content.ToString() == "选中墨迹")
      {
        inkCanvasMeasure.EditingMode = InkCanvasEditingMode.Select;
      }

      else if ((sender as RadioButton).Content.ToString() == "停止操作")
      {
        inkCanvasMeasure.EditingMode = InkCanvasEditingMode.None;
      }
    }

    private void SaveInkCanvas_Click(object sender, RoutedEventArgs e)
    {
      FileStream fileStream = new FileStream("inkCanvas.isf", FileMode.Create, FileAccess.ReadWrite);
      inkCanvasMeasure.Strokes.Save(fileStream);
      fileStream.Close();
    }

    private void LoadInkCanvas_Click(object sender, RoutedEventArgs e)
    {
      FileStream fileStream = new FileStream("inkCanvas.isf", FileMode.Open, FileAccess.Read);
      inkCanvasMeasure.Strokes = new StrokeCollection(fileStream);
      fileStream.Close();
    }

    private void CopyInkCanvas_Click(object sender, RoutedEventArgs e)
    {
      inkCanvasMeasure.CopySelection();
    }
    private void PasteInkCanvas_Click(object sender, RoutedEventArgs e)
    {
      inkCanvasMeasure.Paste();
    }
  }
}

ViewModel.cs代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

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");
      }
    }
  }
}

补充说明：将Image和InkCanvas放到一个Grid里，并且将InkCanvas的长宽绑定到Image，这样Image和InkCanvas的位置就是对应的，方便我后续在InkCanvas上提取Image的感兴趣区域；InkCanvas里加了一个Label可以实现类似图片上添加文字说明的功能，要设置Label的IsHitTestVisible="False"，不然点击事件就没办法触发了。

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