Refactor tests, splitting out Consolonia.NUnit library and a ton of unit tests

src/Consolonia.Core/Assembly.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Runtime.CompilerServices;
 
-[assembly: InternalsVisibleTo("Consolonia.TestsCore")]
+[assembly: InternalsVisibleTo("Consolonia.Core.Tests")]
 
 [assembly: CLSCompliant(false)] //todo: should we make it compliant?

src/Consolonia.Core/Consolonia.Core.csproj

@@ -6,8 +6,9 @@
         <PackageReference Include="Avalonia.FreeDesktop" Version="$(AvaloniaVersion)" />
         <PackageReference Include="Avalonia.Skia" Version="$(AvaloniaVersion)" />
         <PackageReference Include="Avalonia.Controls.DataGrid" Version="$(AvaloniaVersion)" />
-        <PackageReference Include="NullLib.ConsoleEx" Version="1.0.4.4" />
         <PackageReference Include="SkiaSharp.NativeAssets.Linux.NoDependencies" Version="2.88.8" />
+        <PackageReference Include="Unicode.net" Version="2.0.0" />
+        <PackageReference Include="Wcwidth" Version="2.0.0" />
     </ItemGroup>
 
 </Project>

src/Consolonia.Core/Drawing/ConsoleBrush.cs

@@ -1,11 +1,13 @@
 using System;
+using System.Diagnostics;
 using Avalonia;
 using Avalonia.Media;
 using Consolonia.Core.Drawing.PixelBufferImplementation;
 using Consolonia.Core.Infrastructure;
 
 namespace Consolonia.Core.Drawing
 {
+    [DebuggerDisplay("{Color} [{Mode}]")]
     public class ConsoleBrush : AvaloniaObject, IImmutableBrush
     {
         public static readonly StyledProperty<Color> ColorProperty =

src/Consolonia.Core/Drawing/DrawingContextImpl.cs

@@ -5,8 +5,10 @@
 using Avalonia;
 using Avalonia.Media;
 using Avalonia.Media.Immutable;
+using Avalonia.Media.TextFormatting;
 using Avalonia.Platform;
 using Consolonia.Core.Drawing.PixelBufferImplementation;
+using Consolonia.Core.Helpers;
 using Consolonia.Core.Infrastructure;
 using Consolonia.Core.InternalHelpers;
 using Consolonia.Core.Text;
@@ -24,7 +26,8 @@ internal class DrawingContextImpl : IDrawingContextImpl
         private const byte HorizontalEndPattern = 0b0001;
 
         public const int UnderlineThickness = 10;
-        public const int StrikthroughThickness = 11;
+        public const int StrikethroughThickness = 11;
+
         private readonly Stack<Rect> _clipStack = new(100);
         private readonly ConsoleWindow _consoleWindow;
         private readonly PixelBuffer _pixelBuffer;
@@ -91,7 +94,8 @@ public void DrawBitmap(IBitmapImpl source, double opacity, Rect sourceRect, Rect
                 Color foreground = GetForegroundColorForQuadPixel(quadColors, quadPixel);
                 Color background = GetBackgroundColorForQuadPixel(quadColors, quadPixel);
 
-                var imagePixel = new Pixel(new PixelForeground(new SimpleSymbol(quadPixel), color: foreground),
+                var imagePixel = new Pixel(
+                    new PixelForeground(new SimpleSymbol(quadPixel), color: foreground),
                     new PixelBackground(background));
                 CurrentClip.ExecuteWithClipping(new Point(px, py),
                     () =>
@@ -206,9 +210,9 @@ public void DrawGlyphRun(IBrush foreground, IGlyphRunImpl glyphRun)
                 return;
             }
 
-            string charactersDoDraw =
-                string.Concat(glyphRunImpl.GlyphIndices.Select(us => (char)us).ToArray());
-            DrawStringInternal(foreground, charactersDoDraw, glyphRun.GlyphTypeface);
+            var shapedBuffer = (ShapedBuffer)glyphRunImpl.GlyphInfos;
+            string text = shapedBuffer.Text.ToString();
+            DrawStringInternal(foreground, text, glyphRun.GlyphTypeface);
         }
 
         public IDrawingContextLayerImpl CreateLayer(Size size)
@@ -302,9 +306,11 @@ private void DrawLineInternal(IPen pen, Line line)
             line = TransformLineInternal(line);
 
             Point head = line.PStart;
-
-            if (IfMoveConsoleCaretMove(pen, head))
+            if (pen.Brush is MoveConsoleCaretToPositionBrush)
+            {
+                _pixelBuffer.SetCaretPosition((PixelBufferCoordinate)head);
                 return;
+            }
 
             if (line.Vertical == false && pen.Thickness > 1)
             {
@@ -328,7 +334,7 @@ private void ApplyTextDecorationLineInternal(ref Point head, IPen pen, Line line
             TextDecorationCollection textDecoration = pen.Thickness switch
             {
                 UnderlineThickness => TextDecorations.Underline,
-                StrikthroughThickness => TextDecorations.Strikethrough,
+                StrikethroughThickness => TextDecorations.Strikethrough,
                 _ => throw new ArgumentOutOfRangeException($"Unsupported thickness {pen.Thickness}")
             };
 
@@ -342,10 +348,10 @@ private void ApplyTextDecorationLineInternal(ref Point head, IPen pen, Line line
                         pixel =>
                         {
                             var newPixelForeground = new PixelForeground(pixel.Foreground.Symbol,
+                                pixel.Foreground.Color,
                                 pixel.Foreground.Weight,
                                 pixel.Foreground.Style,
-                                textDecoration,
-                                pixel.Foreground.Color);
+                                textDecoration);
                             return pixel.Blend(new Pixel(newPixelForeground, pixel.Background));
                         });
                 });
@@ -366,8 +372,11 @@ private void DrawRectangleLineInternal(IPen pen, Line line)
 
             Point head = line.PStart;
 
-            if (IfMoveConsoleCaretMove(pen, head))
+            if (pen.Brush is MoveConsoleCaretToPositionBrush)
+            {
+                _pixelBuffer.SetCaretPosition((PixelBufferCoordinate)head);
                 return;
+            }
 
             var extractColorCheckPlatformSupported = ExtractColorOrNullWithPlatformCheck(pen, out var lineStyle);
             if (extractColorCheckPlatformSupported == null)
@@ -398,22 +407,6 @@ private Line TransformLineInternal(Line line)
             return line;
         }
 
-        /// <summary>
-        ///     If the pen brush is a MoveConsoleCaretToPositionBrush, move the caret
-        /// </summary>
-        /// <param name="pen"></param>
-        /// <param name="head"></param>
-        /// <returns></returns>
-        private bool IfMoveConsoleCaretMove(IPen pen, Point head)
-        {
-            if (pen.Brush is not MoveConsoleCaretToPositionBrush)
-                return false;
-
-            CurrentClip.ExecuteWithClipping(head,
-                () => { _pixelBuffer.Set((PixelBufferCoordinate)head, pixel => pixel.Blend(new Pixel(true))); });
-            return true;
-        }
-
         /// <summary>
         ///     Extract color from pen brush
         /// </summary>
@@ -486,7 +479,7 @@ private void DrawPixelAndMoveHead(ref Point head, Line line, LineStyle? lineStyl
             }
         }
 
-        private void DrawStringInternal(IBrush foreground, string str, IGlyphTypeface typeface, Point origin = new())
+        private void DrawStringInternal(IBrush foreground, string text, IGlyphTypeface typeface, Point origin = new())
         {
             foreground = ConsoleBrush.FromBrush(foreground);
             if (foreground is not ConsoleBrush { Mode: PixelBackgroundMode.Colored } consoleBrush)
@@ -495,23 +488,27 @@ private void DrawPixelAndMoveHead(ref Point head, Line line, LineStyle? lineStyl
                 return;
             }
 
-            //if (!Transform.IsTranslateOnly()) ConsoloniaPlatform.RaiseNotSupported(15);
+            // if (!Transform.IsTranslateOnly()) ConsoloniaPlatform.RaiseNotSupported(15);
 
             Point whereToDraw = origin.Transform(Transform);
             int currentXPosition = 0;
+            int currentYPosition = 0;
 
-            //todo: support surrogates
-            foreach (char c in str)
+            // Each glyph maps to a pixel as a starting point.
+            // Emoji's and Ligatures are complex strings, so they start at a point and then overlap following pixels
+            // the x and y are adjusted accodingly.
+            foreach (string glyph in text.GetGlyphs(_consoleWindow.Console.SupportsComplexEmoji))
             {
-                Point characterPoint = whereToDraw.Transform(Matrix.CreateTranslation(currentXPosition++, 0));
+                Point characterPoint =
+                    whereToDraw.Transform(Matrix.CreateTranslation(currentXPosition, currentYPosition));
                 Color foregroundColor = consoleBrush.Color;
 
-                switch (c)
+                switch (glyph)
                 {
-                    case '\t':
+                    case "\t":
                     {
                         const int tabSize = 8;
-                        var consolePixel = new Pixel(' ', foregroundColor);
+                        var consolePixel = new Pixel(new SimpleSymbol(' '), foregroundColor);
                         for (int j = 0; j < tabSize; j++)
                         {
                             Point newCharacterPoint = characterPoint.WithX(characterPoint.X + j);
@@ -525,26 +522,26 @@ private void DrawPixelAndMoveHead(ref Point head, Line line, LineStyle? lineStyl
                         currentXPosition += tabSize - 1;
                     }
                         break;
-                    case '\n':
-                    {
-                        /* it's not clear if we need to draw anything. Cursor can be placed at the end of the line
-                         var consolePixel =  new Pixel(' ', foregroundColor);
-
-                        _pixelBuffer.Set((PixelBufferCoordinate)characterPoint,
-                            (oldPixel, cp) => oldPixel.Blend(cp), consolePixel);*/
-                    }
-                        break;
-                    case '\u200B':
-                        currentXPosition--;
+                    case "\r":
+                    case "\f":
+                    case "\n":
+                        currentXPosition = 0;
+                        currentYPosition++;
                         break;
                     default:
                     {
-                        var consolePixel = new Pixel(c, foregroundColor, typeface.Style, typeface.Weight);
+                        var symbol = new SimpleSymbol(glyph);
+                        var consolePixel = new Pixel(symbol, foregroundColor, typeface.Style, typeface.Weight);
                         CurrentClip.ExecuteWithClipping(characterPoint, () =>
                         {
                             _pixelBuffer.Set((PixelBufferCoordinate)characterPoint,
                                 (oldPixel, cp) => oldPixel.Blend(cp), consolePixel);
                         });
+
+                        if (symbol.Width > 1)
+                            currentXPosition += symbol.Width;
+                        else
+                            currentXPosition++;
                     }
                         break;
                 }

src/Consolonia.Core/Drawing/PixelBufferImplementation/DrawingBoxSymbol.cs

@@ -1,34 +1,40 @@
 using System;
+using System.Diagnostics;
 
 namespace Consolonia.Core.Drawing.PixelBufferImplementation
 {
     /// <summary>
     ///     https://en.wikipedia.org/wiki/Box-drawing_character
     /// </summary>
+    [DebuggerDisplay("DrawingBox {Text}")]
     public struct DrawingBoxSymbol : ISymbol
     {
         // all 0bXXXX_0000 are special values
         private const byte BoldSymbol = 0b0001_0000;
         private const byte EmptySymbol = 0b0;
+        private readonly byte _upRightDownLeft;
 
         public DrawingBoxSymbol(byte upRightDownLeft)
         {
             _upRightDownLeft = upRightDownLeft;
+            Text = GetBoxSymbol(_upRightDownLeft).ToString();
         }
 
-        private byte _upRightDownLeft;
+        public string Text { get; private init; }
+
+        public ushort Width { get; } = 1;
 
         /// <summary>
         ///     https://en.wikipedia.org/wiki/Code_page_437
         /// </summary>
-        char ISymbol.GetCharacter()
+        private static char GetBoxSymbol(byte upRightDownLeft)
         {
             //DOS linedraw characters are not ordered in any programmatic manner, and calculating a particular character shape needs to use a look-up table. from https://en.wikipedia.org/wiki/Box-drawing_character
 
-            byte leftPart = (byte)(_upRightDownLeft & 0b1111_0000);
+            byte leftPart = (byte)(upRightDownLeft & 0b1111_0000);
             bool hasLeftPart = leftPart > 0;
 
-            switch (_upRightDownLeft & 0b0000_1111)
+             switch (upRightDownLeft & 0b0000_1111)
             {
                 case 0b0000_1000:
                 case 0b0000_0010:
@@ -50,7 +56,7 @@ char ISymbol.GetCharacter()
 
                 default:
                 {
-                    return _upRightDownLeft switch
+                    return upRightDownLeft switch
                     {
                         EmptySymbol => char.MinValue,
                         BoldSymbol => '█',
@@ -101,27 +107,27 @@ public ISymbol Blend(ref ISymbol symbolAbove)
         {
             if (symbolAbove.IsWhiteSpace()) return this;
 
-            if (symbolAbove is not DrawingBoxSymbol drawingBoxSymbol) return symbolAbove;
+            if (symbolAbove is not DrawingBoxSymbol drawingBoxSymbol) 
+                return symbolAbove;
+
             if (drawingBoxSymbol._upRightDownLeft == BoldSymbol || _upRightDownLeft == BoldSymbol)
-                _upRightDownLeft = BoldSymbol;
-            else
-                _upRightDownLeft |= drawingBoxSymbol._upRightDownLeft;
-
-            return this;
+                return new DrawingBoxSymbol(BoldSymbol);
+
+            return new DrawingBoxSymbol((byte)(_upRightDownLeft | drawingBoxSymbol._upRightDownLeft));
         }
 
-        public static byte UpRightDownLeftFromPattern(byte pattern, LineStyle lineStyle)
+        public static DrawingBoxSymbol UpRightDownLeftFromPattern(byte pattern, LineStyle lineStyle)
         {
-            if (pattern == EmptySymbol) return EmptySymbol;
+            if (pattern == EmptySymbol) return new DrawingBoxSymbol(EmptySymbol);
             switch (lineStyle)
             {
                 case LineStyle.SingleLine:
-                    return pattern;
+                    return new DrawingBoxSymbol(pattern);
                 case LineStyle.Bold:
-                    return BoldSymbol;
+                    return new DrawingBoxSymbol(BoldSymbol);
                 case LineStyle.DoubleLine:
                     byte leftPart = (byte)(pattern << 4);
-                    return (byte)(leftPart | pattern);
+                    return new DrawingBoxSymbol((byte)(leftPart | pattern));
                 default:
                     throw new ArgumentOutOfRangeException(nameof(lineStyle), lineStyle, null);
             }

src/Consolonia.Core/Drawing/PixelBufferImplementation/ISymbol.cs

@@ -2,8 +2,23 @@ namespace Consolonia.Core.Drawing.PixelBufferImplementation
 {
     public interface ISymbol
     {
-        char GetCharacter();
+        /// <summary>
+        ///     The text for the symbol (This can be single character or unicode encoding for Emoji's and the like)
+        /// </summary>
+        string Text { get; }
+
+        /// <summary>
+        ///     The number of characters the symbol takes up
+        /// </summary>
+        ushort Width { get; }
+
         bool IsWhiteSpace();
+
+        /// <summary>
+        ///     Blend 2 symbols together
+        /// </summary>
+        /// <param name="symbolAbove"></param>
+        /// <returns></returns>
         ISymbol Blend(ref ISymbol symbolAbove);
     }
 }