Add text overflow support

Closes #61

src/Spectre.Console.Tests/Unit/TextTests.cs

@@ -83,5 +83,25 @@ namespace Spectre.Console.Tests.Unit
                 .NormalizeLineEndings()
                 .ShouldBe(expected);
         }
+
+        [Theory]
+        [InlineData(Overflow.Fold, "foo \npneumonoultram\nicroscopicsili\ncovolcanoconio\nsis bar qux")]
+        [InlineData(Overflow.Crop, "foo \npneumonoultram\nbar qux")]
+        [InlineData(Overflow.Ellipsis, "foo \npneumonoultra…\nbar qux")]
+        public void Should_Overflow_Text_Correctly(Overflow overflow, string expected)
+        {
+            // Given
+            var fixture = new PlainConsole(14);
+            var text = new Text("foo pneumonoultramicroscopicsilicovolcanoconiosis bar qux")
+                .SetOverflow(overflow);
+
+            // When
+            fixture.Render(text);
+
+            // Then
+            fixture.Output
+                .NormalizeLineEndings()
+                .ShouldBe(expected);
+        }
     }
 }

src/Spectre.Console/Rendering/Markup.cs

@@ -7,7 +7,7 @@ namespace Spectre.Console
     /// <summary>
     /// A renderable piece of markup text.
     /// </summary>
-    public sealed class Markup : Renderable, IAlignable
+    public sealed class Markup : Renderable, IAlignable, IOverflowable
     {
         private readonly Paragraph _paragraph;
 
@@ -18,6 +18,13 @@ namespace Spectre.Console
             set => _paragraph.Alignment = value;
         }
 
+        /// <inheritdoc/>
+        public Overflow? Overflow
+        {
+            get => _paragraph.Overflow;
+            set => _paragraph.Overflow = value;
+        }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Markup"/> class.
         /// </summary>

src/Spectre.Console/Rendering/Overflow.cs

@@ -0,0 +1,24 @@
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Represents text overflow.
+    /// </summary>
+    public enum Overflow
+    {
+        /// <summary>
+        /// Put any excess characters on the next line.
+        /// </summary>
+        Fold = 0,
+
+        /// <summary>
+        /// Truncates the text at the end of the line.
+        /// </summary>
+        Crop = 1,
+
+        /// <summary>
+        /// Truncates the text at the end of the line and
+        /// also inserts an ellipsis character.
+        /// </summary>
+        Ellipsis = 2,
+    }
+}

src/Spectre.Console/Rendering/Paragraph.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
@@ -12,7 +12,7 @@ namespace Spectre.Console
     /// of the paragraph can have individual styling.
     /// </summary>
     [DebuggerDisplay("{_text,nq}")]
-    public sealed class Paragraph : Renderable, IAlignable
+    public sealed class Paragraph : Renderable, IAlignable, IOverflowable
     {
         private readonly List<SegmentLine> _lines;
 
@@ -21,6 +21,11 @@ namespace Spectre.Console
         /// </summary>
         public Justify? Alignment { get; set; }
 
+        /// <summary>
+        /// Gets or sets the text overflow strategy.
+        /// </summary>
+        public Overflow? Overflow { get; set; }
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Paragraph"/> class.
         /// </summary>
@@ -197,34 +202,76 @@ namespace Spectre.Console
             var line = new SegmentLine();
 
             var newLine = true;
-            using (var iterator = new SegmentLineIterator(_lines))
+
+            using var iterator = new SegmentLineIterator(_lines);
+            var queue = new Queue<Segment>();
+            while (true)
             {
-                while (iterator.MoveNext())
+                var current = (Segment?)null;
+                if (queue.Count == 0)
                 {
-                    var current = iterator.Current;
-                    if (current == null)
+                    if (!iterator.MoveNext())
                     {
-                        throw new InvalidOperationException("Iterator returned empty segment.");
+                        break;
                     }
 
-                    if (newLine && current.IsWhiteSpace && !current.IsLineBreak)
-                    {
-                        newLine = false;
-                        continue;
-                    }
+                    current = iterator.Current;
+                }
+                else
+                {
+                    current = queue.Dequeue();
+                }
 
+                if (current == null)
+                {
+                    throw new InvalidOperationException("Iterator returned empty segment.");
+                }
+
+                if (newLine && current.IsWhiteSpace && !current.IsLineBreak)
+                {
                     newLine = false;
+                    continue;
+                }
 
-                    if (current.IsLineBreak)
+                newLine = false;
+
+                if (current.IsLineBreak)
+                {
+                    line.Add(current);
+                    lines.Add(line);
+                    line = new SegmentLine();
+                    newLine = true;
+                    continue;
+                }
+
+                var length = current.CellLength(context.Encoding);
+                if (length > maxWidth)
+                {
+                    // The current segment is longer than the width of the console,
+                    // so we will need to crop it up, into new segments.
+                    var segments = Segment.SplitOverflow(current, Overflow, context.Encoding, maxWidth);
+                    if (segments.Count > 0)
                     {
-                        line.Add(current);
-                        lines.Add(line);
-                        line = new SegmentLine();
-                        newLine = true;
-                        continue;
-                    }
+                        if (line.CellWidth(context.Encoding) + segments[0].CellLength(context.Encoding) > maxWidth)
+                        {
+                            lines.Add(line);
+                            line = new SegmentLine();
+                            newLine = true;
 
-                    var length = current.CellLength(context.Encoding);
+                            segments.ForEach(s => queue.Enqueue(s));
+                            continue;
+                        }
+                        else
+                        {
+                            // Add the segment and push the rest of them to the queue.
+                            line.Add(segments[0]);
+                            segments.Skip(1).ForEach(s => queue.Enqueue(s));
+                            continue;
+                        }
+                    }
+                }
+                else
+                {
                     if (line.CellWidth(context.Encoding) + length > maxWidth)
                     {
                         line.Add(Segment.Empty);
@@ -232,16 +279,16 @@ namespace Spectre.Console
                         line = new SegmentLine();
                         newLine = true;
                     }
-
-                    if (newLine && current.IsWhiteSpace)
-                    {
-                        continue;
-                    }
-
-                    newLine = false;
-
-                    line.Add(current);
                 }
+
+                if (newLine && current.IsWhiteSpace)
+                {
+                    continue;
+                }
+
+                newLine = false;
+
+                line.Add(current);
             }
 
             // Flush remaining.

src/Spectre.Console/Rendering/Segment.cs

@@ -261,6 +261,57 @@ namespace Spectre.Console.Rendering
             return result;
         }
 
+        /// <summary>
+        /// Splits an overflowing segment into several new segments.
+        /// </summary>
+        /// <param name="segment">The segment to split.</param>
+        /// <param name="overflow">The overflow strategy to use.</param>
+        /// <param name="encoding">The encodign to use.</param>
+        /// <param name="width">The maxiumum width.</param>
+        /// <returns>A list of segments that has been split.</returns>
+        public static List<Segment> SplitOverflow(Segment segment, Overflow? overflow, Encoding encoding, int width)
+        {
+            if (segment is null)
+            {
+                throw new ArgumentNullException(nameof(segment));
+            }
+
+            if (segment.CellLength(encoding) <= width)
+            {
+                return new List<Segment>(1) { segment };
+            }
+
+            // Default to folding
+            overflow ??= Overflow.Fold;
+
+            var result = new List<Segment>();
+
+            if (overflow == Overflow.Fold)
+            {
+                var totalLength = segment.Text.CellLength(encoding);
+                var lengthLeft = totalLength;
+                while (lengthLeft > 0)
+                {
+                    var index = totalLength - lengthLeft;
+                    var take = Math.Min(width, totalLength - index);
+
+                    result.Add(new Segment(segment.Text.Substring(index, take), segment.Style));
+                    lengthLeft -= take;
+                }
+            }
+            else if (overflow == Overflow.Crop)
+            {
+                result.Add(new Segment(segment.Text.Substring(0, width), segment.Style));
+            }
+            else if (overflow == Overflow.Ellipsis)
+            {
+                result.Add(new Segment(segment.Text.Substring(0, width - 1), segment.Style));
+                result.Add(new Segment("…", segment.Style));
+            }
+
+            return result;
+        }
+
         internal static List<List<SegmentLine>> MakeSameHeight(int cellHeight, List<List<SegmentLine>> cells)
         {
             foreach (var cell in cells)

src/Spectre.Console/Rendering/Text.cs

@@ -10,7 +10,7 @@ namespace Spectre.Console
     /// </summary>
     [DebuggerDisplay("{_text,nq}")]
     [SuppressMessage("Naming", "CA1724:Type names should not match namespaces")]
-    public sealed class Text : Renderable, IAlignable
+    public sealed class Text : Renderable, IAlignable, IOverflowable
     {
         private readonly Paragraph _paragraph;
 
@@ -38,6 +38,15 @@ namespace Spectre.Console
             set => _paragraph.Alignment = value;
         }
 
+        /// <summary>
+        /// Gets or sets the text overflow strategy.
+        /// </summary>
+        public Overflow? Overflow
+        {
+            get => _paragraph.Overflow;
+            set => _paragraph.Overflow = value;
+        }
+
         /// <inheritdoc/>
         protected override Measurement Measure(RenderContext context, int maxWidth)
         {

src/Spectre.Console/Rendering/Traits/Extensions/OverflowableExtensions.cs

@@ -0,0 +1,80 @@
+using System;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Contains extension methods for <see cref="IOverflowable"/>.
+    /// </summary>
+    public static class OverflowableExtensions
+    {
+        /// <summary>
+        /// Folds any overflowing text.
+        /// </summary>
+        /// <typeparam name="T">An object implementing <see cref="IOverflowable"/>.</typeparam>
+        /// <param name="obj">The overflowable object instance.</param>
+        /// <returns>The same instance so that multiple calls can be chained.</returns>
+        public static T Fold<T>(this T obj)
+            where T : class, IOverflowable
+        {
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+
+            return SetOverflow(obj, Overflow.Fold);
+        }
+
+        /// <summary>
+        /// Crops any overflowing text.
+        /// </summary>
+        /// <typeparam name="T">An object implementing <see cref="IOverflowable"/>.</typeparam>
+        /// <param name="obj">The overflowable object instance.</param>
+        /// <returns>The same instance so that multiple calls can be chained.</returns>
+        public static T Crop<T>(this T obj)
+            where T : class, IOverflowable
+        {
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+
+            return SetOverflow(obj, Overflow.Crop);
+        }
+
+        /// <summary>
+        /// Crops any overflowing text and adds an ellipsis to the end.
+        /// </summary>
+        /// <typeparam name="T">An object implementing <see cref="IOverflowable"/>.</typeparam>
+        /// <param name="obj">The overflowable object instance.</param>
+        /// <returns>The same instance so that multiple calls can be chained.</returns>
+        public static T Ellipsis<T>(this T obj)
+            where T : class, IOverflowable
+        {
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+
+            return SetOverflow(obj, Overflow.Ellipsis);
+        }
+
+        /// <summary>
+        /// Sets the overflow strategy.
+        /// </summary>
+        /// <typeparam name="T">An object implementing <see cref="IOverflowable"/>.</typeparam>
+        /// <param name="obj">The overflowable object instance.</param>
+        /// <param name="overflow">The overflow strategy to use.</param>
+        /// <returns>The same instance so that multiple calls can be chained.</returns>
+        public static T SetOverflow<T>(this T obj, Overflow overflow)
+            where T : class, IOverflowable
+        {
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+
+            obj.Overflow = overflow;
+            return obj;
+        }
+    }
+}

src/Spectre.Console/Rendering/Traits/IOverflowable.cs

@@ -0,0 +1,13 @@
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Represents something that can overflow.
+    /// </summary>
+    public interface IOverflowable
+    {
+        /// <summary>
+        /// Gets or sets the text overflow strategy.
+        /// </summary>
+        Overflow? Overflow { get; set; }
+    }
+}