feat: position hardware cursor

- add cursor marker extraction for rendered lines

- move the terminal cursor after full and differential renders

- update input to use the real cursor instead of a block glyph

src/Example/Program.cs

@@ -42,8 +42,7 @@ page.Add(new Box(eventsText, textMeasurer) { Title = "事件" });
 
 runtime.Add(page);
 runtime.SetFocus(input);
-
-terminalOutput.HideCursor();
+terminalOutput.ShowCursor();
 
 try
 {

src/TinyTUI/Components/Input.cs

@@ -1,5 +1,6 @@
 using System.Text;
 using TinyTUI.Input;
+using TinyTUI.Rendering;
 using TinyTUI.Text;
 
 namespace TinyTUI.Components;
@@ -39,8 +40,7 @@ public sealed class Input(ITextMeasurer? textMeasurer = null) : IInputComponent
     /// <inheritdoc />
     public IReadOnlyList<string> Render(int width)
     {
-        var cursor = "█";
-        var visible = $"{Prompt}{Value}{cursor}";
+        var visible = $"{Prompt}{Value}{CursorMarker.Marker}";
         return [_textMeasurer.Truncate(visible, width)];
     }
 

src/TinyTUI/Rendering/CursorMarker.cs

@@ -0,0 +1,34 @@
+using TinyTUI.Text;
+
+namespace TinyTUI.Rendering;
+
+/// <summary>
+/// 提供组件渲染时标记逻辑光标位置的工具
+/// </summary>
+public static class CursorMarker
+{
+    /// <summary>
+    /// 表示逻辑光标位置的不可见标记
+    /// </summary>
+    public const string Marker = "\e_TinyTUI:cursor\e\\";
+
+    /// <summary>
+    /// 从渲染行中提取光标位置并移除标记
+    /// </summary>
+    public static CursorPosition? Extract(IList<string> lines, ITextMeasurer textMeasurer)
+    {
+        for (var row = 0; row < lines.Count; row++)
+        {
+            var markerIndex = lines[row].IndexOf(Marker, StringComparison.Ordinal);
+            if (markerIndex < 0)
+                continue;
+
+            var before = lines[row][..markerIndex];
+            var column = textMeasurer.GetWidth(before);
+            lines[row] = lines[row].Remove(markerIndex, Marker.Length);
+            return new CursorPosition(row + 1, column + 1);
+        }
+
+        return null;
+    }
+}

src/TinyTUI/Rendering/CursorPosition.cs

@@ -0,0 +1,6 @@
+namespace TinyTUI.Rendering;
+
+/// <summary>
+/// 表示终端中的一基光标位置
+/// </summary>
+public readonly record struct CursorPosition(int Row, int Column);

src/TinyTUI/Rendering/DifferentialRenderer.cs

@@ -26,14 +26,15 @@ public sealed class DifferentialRenderer(ITerminalOutput output, ITextMeasurer?
     public void Render(IReadOnlyList<string> lines, TerminalSize size)
     {
         var nextLines = NormalizeLines(lines, size.Columns);
+        var cursor = CursorMarker.Extract(nextLines, _textMeasurer);
 
         if (_previousSize != size)
         {
-            RenderFull(nextLines, size);
+            RenderFull(nextLines, size, cursor);
             return;
         }
 
-        RenderDiff(nextLines, size);
+        RenderDiff(nextLines, size, cursor);
     }
 
     /// <inheritdoc />
@@ -45,7 +46,7 @@ public sealed class DifferentialRenderer(ITerminalOutput output, ITextMeasurer?
         output.Flush();
     }
 
-    private void RenderFull(List<string> lines, TerminalSize size)
+    private void RenderFull(List<string> lines, TerminalSize size, CursorPosition? cursor)
     {
         FullRedrawCount++;
         output.ClearScreen();
@@ -56,12 +57,13 @@ public sealed class DifferentialRenderer(ITerminalOutput output, ITextMeasurer?
             output.Write("\r\n");
         }
 
+        MoveCursor(cursor);
         output.Flush();
         _previousLines = lines;
         _previousSize = size;
     }
 
-    private void RenderDiff(List<string> lines, TerminalSize size)
+    private void RenderDiff(List<string> lines, TerminalSize size, CursorPosition? cursor)
     {
         var maxLineCount = Math.Max(lines.Count, _previousLines.Count);
         var changed = false;
@@ -86,9 +88,18 @@ public sealed class DifferentialRenderer(ITerminalOutput output, ITextMeasurer?
             }
         }
 
-        if (changed)
+        if (cursor is not null)
         {
-            DifferentialRedrawCount++;
+            MoveCursor(cursor);
+        }
+
+        if (changed || cursor is not null)
+        {
+            if (changed)
+            {
+                DifferentialRedrawCount++;
+            }
+
             output.Flush();
         }
 
@@ -100,4 +111,12 @@ public sealed class DifferentialRenderer(ITerminalOutput output, ITextMeasurer?
     {
         return [.. lines.Select(line => _textMeasurer.Truncate(line, width))];
     }
+
+    private void MoveCursor(CursorPosition? cursor)
+    {
+        if (cursor is { } position)
+        {
+            output.MoveCursorTo(position.Row, position.Column);
+        }
+    }
 }

src/TinyTUI/Rendering/FullScreenRenderer.cs

@@ -13,14 +13,18 @@ public sealed class FullScreenRenderer(ITerminalOutput output, ITextMeasurer? te
     /// <inheritdoc />
     public void Render(IReadOnlyList<string> lines, TerminalSize size)
     {
+        var nextLines = NormalizeLines(lines, size.Columns);
+        var cursor = CursorMarker.Extract(nextLines, _textMeasurer);
+
         output.ClearScreen();
 
-        foreach (var line in lines)
+        foreach (var line in nextLines)
         {
-            output.Write(_textMeasurer.Truncate(line, size.Columns));
+            output.Write(line);
             output.Write("\r\n");
         }
 
+        MoveCursor(cursor);
         output.Flush();
     }
 
@@ -30,4 +34,17 @@ public sealed class FullScreenRenderer(ITerminalOutput output, ITextMeasurer? te
         output.ClearScreen();
         output.Flush();
     }
+
+    private List<string> NormalizeLines(IReadOnlyList<string> lines, int width)
+    {
+        return [.. lines.Select(line => _textMeasurer.Truncate(line, width))];
+    }
+
+    private void MoveCursor(CursorPosition? cursor)
+    {
+        if (cursor is { } position)
+        {
+            output.MoveCursorTo(position.Row, position.Column);
+        }
+    }
 }

src/TinyTUI/Stdout/ConsoleTerminalOutput.cs

@@ -52,6 +52,12 @@ public sealed class ConsoleTerminalOutput : ITerminalOutput
         Write("\x1b[?25h");
     }
 
+    /// <inheritdoc />
+    public void MoveCursorTo(int row, int column)
+    {
+        Write($"\e[{row};{column}H");
+    }
+
     private static TextWriter CreateConsoleWriter()
     {
         if (!Console.IsOutputRedirected)

src/TinyTUI/Stdout/ITerminalOutput.cs

@@ -29,4 +29,9 @@ public interface ITerminalOutput
     /// 显示硬件光标
     /// </summary>
     void ShowCursor();
+
+    /// <summary>
+    /// 移动硬件光标到指定的一基位置
+    /// </summary>
+    void MoveCursorTo(int row, int column);
 }