Windows WPF或Silverlight中的VT100终端仿真

Question

我正在考虑创建一个像终端窗口一样的WPF或Silverlight应用程序.除了,因为它在WPF/Silverlight中,它将能够通过效果,图像等"增强"终端体验.

我正试图找出模拟终端的最佳方法.我知道如何处理VT100仿真,就解析等而言.但是如何显示呢？我考虑过使用RichTextBox并将VT100转义代码转换为RTF.

我看到的问题是性能.终端可能一次只能获得几个字符,并且为了能够将它们加载到文本框中,我将不断创建TextRanges并使用Load()来加载RTF.此外,为了完成每个加载"会话",它必须完全描述RTF.例如,如果当前颜色为红色,则每个加载到TextBox中都需要RTF代码才能使文本变为红色,或者我认为RTB不会将其加载为红色.

这似乎非常多余 - 由仿真构建的RTF文档将非常混乱.此外,插入符号的移动似乎不是理想情况下RTB处理的.我需要一些自定义的东西,但是这让我很害怕!

希望听到明亮的想法或指向现有解决方案.也许有一种方法可以在其上嵌入一个实际的终端和覆盖物.我发现的唯一的东西是旧的WinForms控件.

更新:在下面的答案中查看由于perf的建议解决方案是如何失败的.:(
Windows WPF或Silverlight中的VT100终端仿真

Answer 1

If you try to implement this with RichTextBox and RTF you will quickly run into many limitations and find yourself spending much more time working around differences than if you implemented the functionality yourself.

In fact it is quite easy to implement VT100 terminal emulation using WPF. I know because just now I implemented an almost-complete VT100 emulator in an hour or so. To be precise, I implmented everything except:

• Keyboard input,
• Alternate character sets,
• A few esoteric VT100 modes I've never seen used,

The most interesting parts were:

• The double width/double height characters, for which I used RenderTransform and RenderTransformOrigin
• The blinking, for which I used an animation on a shared object so all characters will blink together
• The underline, for which I used a Grid and a Rectangle so it would look more like a VT100 display
• 光标和选择,我在单元格上设置了一个标志,并使用DataTriggers来更改显示
• 使用指向同一对象的一维数组和嵌套数组,可以轻松进行滚动和选择

这是XAML:

<Style TargetType="my:VT100Terminal">
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="my:VT100Terminal">
        <DockPanel>
          <!-- Add status bars, etc to the DockPanel at this point -->
          <ContentPresenter Content="{Binding Display}" />
        </DockPanel>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

<ItemsPanelTemplate x:Key="DockPanelLayout">
  <DockPanel />
</ItemsPanelTemplate>

<DataTemplate DataType="{x:Type my:TerminalDisplay}">
  <ItemsControl ItemsSource="{Binding Lines}" TextElement.FontFamily="Courier New">
    <ItemsControl.ItemTemplate>
      <DataTemplate>
        <ItemsControl ItemsSource="{Binding}" ItemsPanel="{StaticResource DockPanelLayout}" />
      </DataTemplate>
    </ItemsControl.ItemTemplate>
  </ItemsControl>
</DataTemplate>

<DataTemplate DataType="{x:Type my:TerminalCell}">
  <Grid>
    <TextBlock x:Name="tb"
        Text="{Binding Character}"
        Foreground="{Binding Foreground}"
        Background="{Binding Background}"
        FontWeight="{Binding FontWeight}"
        RenderTransformOrigin="{Binding TranformOrigin}">
        <TextBlock.RenderTransform>
          <ScaleTransform ScaleX="{Binding ScaleX}" ScaleY="{Binding ScaleY}" />
        </TextBlock.RenderTransform>
    </TextBlock>
    <Rectangle Visibility="{Binding UnderlineVisiblity}" Height="1" HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Margin="0 0 0 2" />
  </Grid>
  <DataTemplate.Triggers>
    <DataTrigger Binding="{Binding IsCursor}" Value="true">
      <Setter TargetName="tb" Property="Foreground" Value="{Binding Background}" />
      <Setter TargetName="tb" Property="Background" Value="{Binding Foreground}" />
    </DataTrigger>
    <DataTrigger Binding="{Binding IsMouseSelected}" Value="true">
      <Setter TargetName="tb" Property="Foreground" Value="White" />
      <Setter TargetName="tb" Property="Background" Value="Blue" />
    </DataTrigger>
  </DataTemplate.Triggers>
</DataTemplate>

以下是代码:

public class VT100Terminal : Control
{
  bool _selecting;

  static VT100Terminal()
  {
    DefaultStyleKeyProperty.OverrideMetadata(typeof(VT100Terminal), new FrameworkPropertyMetadata(typeof(VT100Terminal)));
  }

  // Display
  public TerminalDisplay Display { get { return (TerminalDisplay)GetValue(DisplayProperty); } set { SetValue(DisplayProperty, value); } }
  public static readonly DependencyProperty DisplayProperty = DependencyProperty.Register("Display", typeof(TerminalDisplay), typeof(VT100Terminal));

  public VT100Terminal()
  {
    Display = new TerminalDisplay();

    MouseLeftButtonDown += HandleMouseMessage;
    MouseMove += HandleMouseMessage;
    MouseLeftButtonUp += HandleMouseMessage;

    KeyDown += HandleKeyMessage;

    CommandBindings.Add(new CommandBinding(ApplicationCommands.Copy, ExecuteCopy, CanExecuteCopy));
  }

  public void ProcessCharacter(char ch)
  {
    Display.ProcessCharacter(ch);
  }

  private void HandleMouseMessage(object sender, MouseEventArgs e)
  {
    if(!_selecting && e.RoutedEvent != Mouse.MouseDownEvent) return;
    if(e.RoutedEvent == Mouse.MouseUpEvent) _selecting = false;

    var block = e.Source as TextBlock; if(block==null) return;
    var cell = ((TextBlock)e.Source).DataContext as TerminalCell; if(cell==null) return;
    var index = Display.GetIndex(cell); if(index<0) return;
    if(e.GetPosition(block).X > block.ActualWidth/2) index++;

    if(e.RoutedEvent == Mouse.MouseDownEvent)
    {
      Display.SelectionStart = index;
      _selecting = true;
    }
    Display.SelectionEnd = index;
  }

  private void HandleKeyMessage(object sender, KeyEventArgs e)
  {
    // TODO: Code to covert e.Key to VT100 codes and report keystrokes to client
  }

  private void CanExecuteCopy(object sender, CanExecuteRoutedEventArgs e)
  {
    if(Display.SelectedText!="") e.CanExecute = true;
  }
  private void ExecuteCopy(object sender, ExecutedRoutedEventArgs e)
  {
    if(Display.SelectedText!="")
    {
      Clipboard.SetText(Display.SelectedText);
      e.Handled = true;
    }
  }
}

public enum CharacterDoubling
{
  Normal = 5,
  Width = 6,
  HeightUpper = 3,
  HeightLower = 4,
}

public class TerminalCell : INotifyPropertyChanged
{
  char _character;
  Brush _foreground, _background;
  CharacterDoubling _doubling;
  bool _isBold, _isUnderline;
  bool _isCursor, _isMouseSelected;

  public char Character { get { return _character; } set { _character = value; Notify("Character", "Text"); } }
  public Brush Foreground { get { return _foreground; } set { _foreground = value; Notify("Foreground"); } }
  public Brush Background { get { return _background; } set { _background = value; Notify("Background"); } }
  public CharacterDoubling Doubling { get { return _doubling; } set { _doubling = value; Notify("Doubling", "ScaleX", "ScaleY", "TransformOrigin"); } }
  public bool IsBold { get { return _isBold; } set { _isBold = value; Notify("IsBold", "FontWeight"); } }
  public bool IsUnderline { get { return _isUnderline; } set { _isUnderline = value; Notify("IsUnderline", "UnderlineVisibility"); } }

  public bool IsCursor { get { return _isCursor; } set { _isCursor = value; Notify("IsCursor"); } }
  public bool IsMouseSelected { get { return _isMouseSelected; } set { _isMouseSelected = value; Notify("IsMouseSelected"); } }

  public string Text { get { return Character.ToString(); } }
  public int ScaleX { get { return Doubling!=CharacterDoubling.Normal ? 2 : 1; } }
  public int ScaleY { get { return Doubling==CharacterDoubling.HeightUpper || Doubling==CharacterDoubling.HeightLower ? 2 : 1; } }
  public Point TransformOrigin { get { return Doubling==CharacterDoubling.HeightLower ? new Point(1,0) : new Point(0,0); } }
  public FontWeight FontWeight { get { return IsBold ? FontWeights.Bold : FontWeights.Normal; } }
  public Visibility UnderlineVisibility { get { return IsUnderline ? Visibility.Visible : Visibility.Hidden; } }

  // INotifyPropertyChanged implementation
  private void Notify(params string[] propertyNames) { foreach(string name in propertyNames) Notify(name); }
  private void Notify(string propertyName)
  {
    if(PropertyChanged!=null)
      PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
  }
  public event PropertyChangedEventHandler PropertyChanged;
}

public class TerminalDisplay : INotifyPropertyChanged
{
  // Basic state
  private TerminalCell[] _buffer;
  private TerminalCell[][] _lines;
  private int _height, _width;
  private int _row, _column; // Cursor position
  private int _scrollTop, _scrollBottom;
  private List<int> _tabStops;
  private int _selectStart, _selectEnd; // Text selection
  private int _saveRow, _saveColumn; // Saved location

  // Escape character processing
  string _escapeChars, _escapeArgs;

  // Modes
  private bool _vt52Mode;
  private bool _autoWrapMode;
  // current attributes
  private bool _boldMode, _lowMode, _underlineMode, _blinkMode, _reverseMode, _invisibleMode;
  // saved attributes
  private bool _saveboldMode, _savelowMode, _saveunderlineMode, _saveblinkMode, _savereverseMode, _saveinvisibleMode;
  private Color _foreColor, _backColor;
  private CharacterDoubling _doubleMode;

  // Computed from current mode
  private Brush _foreground;
  private Brush _background;

  // Hidden control used to synchronize blinking
  private FrameworkElement _blinkMaster;

  public TerminalDisplay()
  {
    Reset();
  }

  public void Reset()
  {
    _height = 24;
    _width = 80;
    _row = 0;
    _column = 0;
    _scrollTop = 0;
    _scrollBottom = _height;
    _vt52Mode = false;
    _autoWrapMode = true;
    _selectStart = 0;
    _selectEnd = 0;
    _tabStops = new List<int>();
    ResetBuffer();
    ResetCharacterModes();
    UpdateBrushes();
    _saveboldMode = _savelowMode = _saveunderlineMode = _saveblinkMode = _savereverseMode = _saveinvisibleMode = false;
    _saveRow = _saveColumn = 0;
  }
  private void ResetBuffer()
  {
    _buffer = (from i in Enumerable.Range(0, Width * Height) select new TerminalCell()).ToArray();
    UpdateSelection();
    UpdateLines();
  }
  private void ResetCharacterModes()
  {
    _boldMode = _lowMode = _underlineMode = _blinkMode = _reverseMode = _invisibleMode = false;
    _doubleMode = CharacterDoubling.Normal;
    _foreColor = Colors.White;
    _backColor = Colors.Black;
  }

  public int Height { get { return _height; } set { _height = value; ResetBuffer(); } }
  public int Width { get { return _width; } set { _width = value; ResetBuffer(); } }

  public int Row { get { return _row; } set { CursorCell.IsCursor = false; _row=value; CursorCell.IsCursor = true; Notify("Row", "CursorCell"); } }
  public int Column { get { return _column; } set { CursorCell.IsCursor = false; _column=value; CursorCell.IsCursor = true; Notify("Row", "CursorCell"); } }

  public int SelectionStart { get { return _selectStart; } set { _selectStart = value; UpdateSelection(); Notify("SelectionStart", "SelectedText"); } }
  public int SelectionEnd { get { return _selectEnd; } set { _selectEnd = value; UpdateSelection(); Notify("SelectionEnd", "SelectedText"); } }

  public TerminalCell[][] Lines { get { return _lines; } }

  public TerminalCell CursorCell { get { return GetCell(_row, _column); } }

  public TerminalCell GetCell(int row, int column)
  {
    if(row<0 || row>=Height || column<0 || column>=Width)
      return new TerminalCell();
    return _buffer[row*Height + column];
  }

  public int GetIndex(int row, int column)
  {
    return row * Height + column;
  }

  public int GetIndex(TerminalCell cell)
  {
    return Array.IndexOf(_buffer, cell);
  }

  public string SelectedText
  {
    get
    {
      int start = Math.Min(_selectStart, _selectEnd);
      int end = Math.Max(_selectStart, _selectEnd);
      if(start==end) return string.Empty;
      var builder = new StringBuilder();
      for(int i=start; i<end; i++)
      {
        if(i!=start && (i%Width==0))
        {
          while(builder.Length>0 && builder[builder.Length-1]==' ')
            builder.Length--;
          builder.Append("\r\n");
        }
        builder.Append(_buffer[i].Character);
      }
      return builder.ToString();
    }
  }

  /////////////////////////////////

  public void ProcessCharacter(char ch)
  {
    if(_escapeChars!=null)
    {
      ProcessEscapeCharacter(ch);
      return;
    }
    switch(ch)
    {
      case '\x1b': _escapeChars = ""; _escapeArgs = ""; break;
      case '\r': Column = 0; break;
      case '\n': NextRowWithScroll();break;

      case '\t':
        Column = (from stop in _tabStops where stop>Column select (int?)stop).Min() ?? Width - 1;
        break;

      default:
        CursorCell.Character = ch;
        FormatCell(CursorCell);

        if(CursorCell.Doubling!=CharacterDoubling.Normal) ++Column;
          if(++Column>=Width)
            if(_autoWrapMode)
            {
              Column = 0;
              NextRowWithScroll();
            }
            else
              Column--;
        break;
    }
  }
  private void ProcessEscapeCharacter(char ch)
  {
    if(_escapeChars.Length==0 && "78".IndexOf(ch)>=0)
    {
      _escapeChars += ch.ToString();
    }
    else if(_escapeChars.Length>0 && "()Y".IndexOf(_escapeChars[0])>=0)
    {
      _escapeChars += ch.ToString();
      if(_escapeChars.Length != (_escapeChars[0]=='Y' ? 3 : 2)) return;
    }
    else if(ch==';' || char.IsDigit(ch))
    {
      _escapeArgs += ch.ToString();
      return;
    }
    else
    {
      _escapeChars += ch.ToString();
      if("[#?()Y".IndexOf(ch)>=0) return;
    }
    ProcessEscapeSequence();
    _escapeChars = null;
    _escapeArgs = null;
  }

  private void ProcessEscapeSequence()
  {
    if(_escapeChars.StartsWith("Y"))
    {
      Row = (int)_escapeChars[1] - 64;
      Column = (int)_escapeChars[2] - 64;
      return;
    }
    if(_vt52Mode && (_escapeChars=="D" || _escapeChars=="H")) _escapeChars += "_";

    var args = _escapeArgs.Split(';');
    int? arg0 = args.Length>0 && args[0]!="" ? int.Parse(args[0]) : (int?)null;
    int? arg1 = args.Length>1 && args[1]!="" ? int.Parse(args[1]) : (int?)null;
    switch(_escapeChars)
    {
      case "[A": case "A": Row -= Math.Max(arg0??1, 1); break;
      case "[B": case "B": Row += Math.Max(arg0??1, 1); break;
      case "[c": case "C": Column += Math.Max(arg0??1, 1); break;
      case "[D": case "D": Column -= Math.Max(arg0??1, 1); break;

      case "[f":
      case "[H": case "H_":
        Row = Math.Max(arg0??1, 1) - 1; Column = Math.Max(arg0??1, 1) - 1;
        break;

      case "M": PriorRowWithScroll(); break;
      case "D_": NextRowWithScroll(); break;
      case "E": NextRowWithScroll(); Column = 0; break;

      case "[r": _scrollTop = (arg0??1)-1; _scrollBottom = (arg0??_height); break;

      case "H": if(!_tabStops.Contains(Column)) _tabStops.Add(Column); break;
      case "g": if(arg0==3) _tabStops.Clear(); else _tabStops.Remove(Column); break;

      case "[J": case "J":
        switch(arg0??0)
        {
          case 0: ClearRange(Row, Column, Height, Width); break;
          case 1: ClearRange(0, 0, Row, Column + 1); break;
          case 2: ClearRange(0, 0, Height, Width); break;
        }
        break;
      case "[K": case "K":
        switch(arg0??0)
        {
          case 0: ClearRange(Row, Column, Row, Width); break;
          case 1: ClearRange(Row, 0, Row, Column + 1); break;
          case 2: ClearRange(Row, 0, Row, Width); break;
        }
        break;

      case "?l":
      case "?h":
        var h = _escapeChars=="?h";
        switch(arg0)
        {
          case 2: _vt52Mode = h; break;
          case 3: Width = h ? 132 : 80; ResetBuffer(); break;
          case 7: _autoWrapMode = h; break;
        }
        break;
      case "<": _vt52Mode = false; break;

      case "m":
        if (args.Length == 0) ResetCharacterModes();
        foreach(var arg in args)
            switch(arg)
            {
              case "0": ResetCharacterModes(); break;
              case "1": _boldMode = true; break;
              case "2": _lowMode = true; break;
              case "4": _underlineMode = true; break;
              case "5": _blinkMode = true; break;
              case "7": _reverseMode = true; break;
              case "8": _invisibleMode = true; break;
            }
        UpdateBrushes();
        break;

      case "#3": case "#4": case "#5": case "#6":
        _doubleMode = (CharacterDoubling)((int)_escapeChars[1] - (int)'0');
      break;

      case "[s": _saveRow = Row; _saveColumn = Column; break;
      case "7": _saveRow = Row; _saveColumn = Column;
          _saveboldMode = _boldMode; _savelowMode = _lowMode;
          _saveunderlineMode = _underlineMode; _saveblinkMode = _blinkMode;
          _savereverseMode = _reverseMode; _saveinvisibleMode = _invisibleMode;
          break;
      case "[u": Row = _saveRow; Column = _saveColumn; break;
      case "8": Row = _saveRow; Column = _saveColumn;
          _boldMode = _saveboldMode; _lowMode = _savelowMode;
          _underlineMode = _saveunderlineMode; _blinkMode = _saveblinkMode;
          _reverseMode = _savereverseMode; _invisibleMode = _saveinvisibleMode;
          break;

      case "c": Reset(); break;

      // TODO: Character set selection, several esoteric ?h/?l modes
    }
    if(Column<0) Column=0;
    if(Column>=Width) Column=Width-1;
    if(Row<0) Row=0;
    if(Row>=Height) Row=Height-1;
  }

  private void PriorRowWithScroll()
  {
    if(Row==_scrollTop) ScrollDown(); else Row--;
  }

  private void NextRowWithScroll()
  {
    if(Row==_scrollBottom-1) ScrollUp(); else Row++;
  }

  private void ScrollUp()
  {
    Array.Copy(_buffer, _width * (_scrollTop + 1), _buffer, _width * _scrollTop, _width * (_scrollBottom - _scrollTop - 1));
    ClearRange(_scrollBottom-1, 0, _scrollBottom-1, Width);
    UpdateSelection();
    UpdateLines();
  }

  private void ScrollDown()
  {
    Array.Copy(_buffer, _width * _scrollTop, _buffer, _width * (_scrollTop + 1), _width * (_scrollBottom - _scrollTop - 1));
    ClearRange(_scrollTop, 0, _scrollTop, Width);
    UpdateSelection();
    UpdateLines();
  }

  private void ClearRange(int startRow, int startColumn, int endRow, int endColumn)
  {
    int start = startRow * Width + startColumn;
    int end = endRow * Width + endColumn;
    for(int i=start; i<end; i++)
      ClearCell(_buffer[i]);
  }

  private void ClearCell(TerminalCell cell)
  {
    cell.Character = ' ';
    FormatCell(cell);
  }

  private void FormatCell(TerminalCell cell)
  {
    cell.Foreground = _foreground;
    cell.Background = _background;
    cell.Doubling = _doubleMode;
    cell.IsBold = _boldMode;
    cell.IsUnderline = _underlineMode;
  }

  private void UpdateSelection()
  {
    var cursor = _row * Width + _height;
    var inSelection = false;
    for(int i=0; i<_buffer.Length; i++)
    {
      if(i==_selectStart) inSelection = !inSelection;
      if(i==_selectEnd) inSelection = !inSelection;

      var cell = _buffer[i];
      cell.IsCursor = i==cursor;
      cell.IsMouseSelected = inSelection;
    }
  }

  private void UpdateBrushes()
  {
    var foreColor = _foreColor;
    var backColor = _backColor;
    if(_lowMode)
    {
      foreColor = foreColor * 0.5f + Colors.Black * 0.5f;
      backColor = backColor * 0.5f + Colors.Black * 0.5f;
    }
    _foreground = new SolidColorBrush(foreColor);
    _background = new SolidColorBrush(backColor);
    if(_reverseMode) Swap(ref _foreground, ref _background);
    if(_invisibleMode) _foreground = _background;
    if(_blinkMode)
    {
      if(_blinkMaster==null)
      {
        _blinkMaster = new Control();
        var animation = new DoubleAnimationUsingKeyFrames { RepeatBehavior=RepeatBehavior.Forever, Duration=TimeSpan.FromMilliseconds(1000) };
        animation.KeyFrames.Add(new DiscreteDoubleKeyFrame(0));
        animation.KeyFrames.Add(new DiscreteDoubleKeyFrame(1));
        _blinkMaster.BeginAnimation(UIElement.OpacityProperty, animation);
      }
      var rect = new Rectangle { Fill = _foreground };
      rect.SetBinding(UIElement.OpacityProperty, new Binding("Opacity") { Source = _blinkMaster });
      _foreground = new VisualBrush { Visual = rect };
    }
  }
  private void Swap<T>(ref T a, ref T b)
  {
    var temp = a;
    a = b;
    b = temp;
  }

  private void UpdateLines()
  {
    _lines = new TerminalCell[Height][];
    for(int r=0; r<Height; r++)
    {
      _lines[r] = new TerminalCell[Width];
      Array.Copy(_buffer, r*Height, _lines[r], 0, Width);
    }
  }

  // INotifyPropertyChanged implementation
  private void Notify(params string[] propertyNames) { foreach(string name in propertyNames) Notify(name); }
  private void Notify(string propertyName)
  {
    if(PropertyChanged!=null)
      PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
  }
  public event PropertyChangedEventHandler PropertyChanged;

}

请注意,如果您不喜欢视觉样式,只需更新TerminalCell DataTemplate即可.例如,光标可以是闪烁的矩形而不是实心矩形.

这段代码很有趣.希望它对你有用.它可能有一两个(或三个)错误,因为我从未真正执行它,但我希望这些可以很容易地清除.如果您修复了某些问题,我欢迎您对此答案进行编辑.