Fix remaining TextView issues

Terminal.Gui/ViewBase/View.Drawing.cs

@@ -746,7 +746,7 @@ private void DoDrawComplete (DrawContext? context)
 
         if (!viewTransparent)
         {
-            exclusion.Combine (ViewportToScreen (Viewport), RegionOp.Union);
+            exclusion.Combine (ViewportToScreen (new Rectangle (Point.Empty, Viewport.Size)), RegionOp.Union);
         }
 
         // For transparent layers, also include context drawn regions (text, content, subviews)

Terminal.Gui/Views/TextInput/TextModel.cs

@@ -16,6 +16,7 @@ internal class TextModel
     // Cached max visible line width to avoid O(N×L) rescans on every layout/scroll.
     private int _cachedMaxWidth = -1;
     private int _cachedMaxWidthTabWidth = -1;
+    private Dictionary<int, int> _cachedMaxWidthPerLine = [];
 
     /// <summary>
     ///     Gets the number of times <see cref="GetMaxVisibleLine"/> performed a full line scan.
@@ -34,6 +35,38 @@ internal class TextModel
     /// <summary>Invalidates the cached max line width so the next call to <see cref="GetMaxVisibleLine"/> will rescan.</summary>
     internal void InvalidateMaxWidthCache () => _cachedMaxWidth = -1;
 
+    /// <summary>
+    ///   Determines whether the max width cache should be invalidated based on the line being modified, the column width of the modification, and whether it's an insert or delete operation.
+    /// </summary>
+    /// <param name="line">The line number being modified.</param>
+    /// <param name="isInsert">Indicates whether the operation is an insert. Defaults to true.</param>
+    /// <param name="columnWidth">The width of the column being modified. Defaults to -1 on delete.</param>
+    /// <returns><see langword="true"/> if the cache should be invalidated; otherwise, <see langword="false"/>.</returns>
+    internal bool ShouldInvalidateMaxWidthCache (int line, bool isInsert = true, int columnWidth = -1)
+    {
+        if (_cachedMaxWidth < 0)
+        {
+            return true;
+        }
+
+        if (isInsert)
+        {
+            if (_cachedMaxWidthPerLine.TryGetValue (line, out int cachedLineWidth) && columnWidth > cachedLineWidth)
+            {
+                return true;
+            }
+        }
+        else
+        {
+            if (_cachedMaxWidthPerLine.Count == 1 && _cachedMaxWidthPerLine.ContainsKey (line))
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     /// <summary>Adds a line to the model at the specified position.</summary>
     /// <param name="pos">Line number where the line will be inserted.</param>
     /// <param name="cells">The line of text and color, as a List of Cell.</param>
@@ -96,6 +129,12 @@ public int GetMaxVisibleLine (int first, int last, int tabWidth)
         var maxLength = 0;
         last = last < _lines.Count ? last : _lines.Count;
 
+        // When scanning the full range, reset cached max width per line
+        if (first == 0 && last >= _lines.Count)
+        {
+            _cachedMaxWidthPerLine = [];
+        }
+
         for (int i = first; i < last; i++)
         {
             List<Cell> line = GetLine (i);
@@ -104,6 +143,17 @@ public int GetMaxVisibleLine (int first, int last, int tabWidth)
             if (colsWidth > maxLength)
             {
                 maxLength = colsWidth;
+
+                // Cache max width per line when scanning the full range, and remove cached widths for lines that are no longer the max
+                if (first != 0 || last < _lines.Count)
+                {
+                    continue;
+                }
+                _cachedMaxWidthPerLine = new Dictionary<int, int> { { i, maxLength } };
+            }
+            else if (maxLength == colsWidth)
+            {
+                _cachedMaxWidthPerLine [i] = maxLength;
             }
         }
 

Terminal.Gui/Views/TextInput/TextView/TextView.Commands.cs

@@ -383,8 +383,8 @@ public bool DeleteCharLeft ()
 
         bool retValue = DeleteTextLeft ();
 
-        DoNeededAction ();
         OnContentsChanged ();
+        DoNeededAction ();
 
         return retValue;
     }
@@ -453,37 +453,45 @@ private bool DeleteTextLeft ()
             }
 
             SetWrapModel ();
-            int prowIdx = CurrentRow - 1;
-            List<Cell> prevRow = _model.GetLine (prowIdx);
 
-            _historyText.Add ([[.. prevRow]], InsertionPoint);
+            if (CurrentRow - 1 > -1)
+            {
+                int prowIdx = CurrentRow - 1;
+                List<Cell> prevRow = _model.GetLine (prowIdx);
+
+                _historyText.Add ([[.. prevRow]], InsertionPoint);
 
-            List<List<Cell>> removedLines = [[.. prevRow], [.. GetCurrentLine ()]];
+                List<List<Cell>> removedLines = [[.. prevRow], [.. GetCurrentLine ()]];
 
-            _historyText.Add (removedLines, new Point (CurrentColumn, prowIdx), TextEditingLineStatus.Removed);
+                _historyText.Add (removedLines, new Point (CurrentColumn, prowIdx), TextEditingLineStatus.Removed);
 
-            int prevCount = prevRow.Count;
-            _model.GetLine (prowIdx).AddRange (GetCurrentLine ());
-            _model.RemoveLine (CurrentRow);
+                int prevCount = prevRow.Count;
+                _model.GetLine (prowIdx).AddRange (GetCurrentLine ());
+                _model.RemoveLine (CurrentRow);
+
+                CurrentRow--;
+
+                _historyText.Add ([GetCurrentLine ()], new Point (CurrentColumn, prowIdx), TextEditingLineStatus.Replaced);
+
+                CurrentColumn = prevCount;
+            }
 
             if (_wordWrap)
             {
                 _wrapNeeded = true;
             }
-
-            CurrentRow--;
-
-            _historyText.Add ([GetCurrentLine ()], new Point (CurrentColumn, prowIdx), TextEditingLineStatus.Replaced);
-
-            CurrentColumn = prevCount;
         }
 
-        // Always redraw and update content size because a glyph was deleted
+        // Text was deleted, so it's always needed to redraw and update content size if needed
         SetNeedsDraw ();
-        UpdateContentSize ();
+
+        if (_model.ShouldInvalidateMaxWidthCache (CurrentRow, false))
+        {
+            _model.InvalidateMaxWidthCache ();
+            UpdateContentSize ();
+        }
 
         UpdateWrapModel ();
-        OnContentsChanged ();
 
         return true;
     }
@@ -513,8 +521,13 @@ private bool DeleteTextRight ()
             _historyText.Add (removedLines, InsertionPoint, TextEditingLineStatus.Removed);
             currentLine.AddRange (nextLine);
             _model.RemoveLine (CurrentRow + 1);
+
+            // Text was deleted, so it's always needed to redraw and update content size if needed
             SetNeedsDraw ();
 
+            // _model.RemoveLine already invalidates the max width cache for the removed line, but we also need to check if the merged line's width changed
+            UpdateContentSize ();
+
             _historyText.Add ([[.. currentLine]], InsertionPoint, TextEditingLineStatus.Replaced);
 
             if (_wordWrap)
@@ -531,8 +544,16 @@ private bool DeleteTextRight ()
         _historyText.Add ([[.. currentLine]], InsertionPoint);
 
         currentLine.RemoveAt (CurrentColumn);
+
+        // Text was deleted, so it's always needed to redraw and update content size if needed
         SetNeedsDraw ();
 
+        if (_model.ShouldInvalidateMaxWidthCache (CurrentRow, false))
+        {
+            _model.InvalidateMaxWidthCache ();
+            UpdateContentSize ();
+        }
+
         _historyText.Add ([[.. currentLine]], InsertionPoint, TextEditingLineStatus.Replaced);
 
         if (_wordWrap)
@@ -660,6 +681,7 @@ private bool CutToStartOfLine ()
             UpdateWrapModel ();
 
             DeleteTextLeft ();
+            OnContentsChanged ();
 
             return true;
         }
@@ -750,6 +772,7 @@ private bool KillWordLeft ()
         if (CurrentColumn == 0)
         {
             DeleteTextLeft ();
+            OnContentsChanged ();
 
             _historyText.ReplaceLast ([[.. GetCurrentLine ()]], InsertionPoint, TextEditingLineStatus.Replaced);
 
@@ -1010,6 +1033,7 @@ private bool ProcessTab (bool addTab)
             if (CurrentColumn - 1 > -1 && CurrentColumn - 1 < line.Count && line [CurrentColumn - 1].Grapheme == "\t")
             {
                 DeleteTextLeft ();
+                OnContentsChanged ();
             }
             else
             {

Terminal.Gui/Views/TextInput/TextView/TextView.Movement.cs

@@ -108,7 +108,7 @@ private bool MoveDown ()
 
             CurrentRow++;
 
-            if (CurrentRow >= Viewport.Y + Viewport.Height)
+            if (CurrentRow >= Viewport.Y + Viewport.Height || CurrentRow < Viewport.Y)
             {
                 SetNeedsDraw ();
             }
@@ -145,8 +145,9 @@ private bool MoveEndOfLine ()
         List<Cell> currentLine = GetCurrentLine ();
         CurrentColumn = currentLine.Count;
 
-        if (CurrentColumn >= Viewport.X + Viewport.Width || TextModel.CursorColumn (TextModel.CellsToStringList (currentLine), CurrentColumn, TabWidth, out _, out _) - Viewport.X >= Viewport.Width)
-{
+        if (CurrentColumn >= Viewport.X + Viewport.Width
+            || TextModel.CursorColumn (TextModel.CellsToStringList (currentLine), CurrentColumn, TabWidth, out _, out _) - Viewport.X >= Viewport.Width)
+        {
             SetNeedsDraw ();
         }
         DoNeededAction ();
@@ -160,7 +161,10 @@ private bool MoveLeft ()
         {
             CurrentColumn--;
 
-            if (Viewport.X > 0 && CurrentColumn <= Viewport.X)
+            List<Cell> currentLine = GetCurrentLine ();
+            int cursorColumn = TextModel.CursorColumn (TextModel.CellsToStringList (currentLine), CurrentColumn, TabWidth, out _, out _);
+
+            if ((Viewport.X > 0 && cursorColumn <= Viewport.X) || cursorColumn - Viewport.X >= Viewport.Width)
             {
                 SetNeedsDraw ();
             }
@@ -296,7 +300,9 @@ private bool MoveRight ()
         {
             CurrentColumn++;
 
-            if (CurrentColumn >= currentLine.Count || TextModel.CursorColumn (TextModel.CellsToStringList (currentLine), CurrentColumn, TabWidth, out _, out _) >= Viewport.Width)
+            int cursorColumn = TextModel.CursorColumn (TextModel.CellsToStringList (currentLine), CurrentColumn, TabWidth, out _, out _);
+
+            if (cursorColumn >= currentLine.Count || (Viewport.X > 0 && cursorColumn < Viewport.X) || cursorColumn >= Viewport.X + Viewport.Width)
             {
                 SetNeedsDraw ();
             }
@@ -346,16 +352,19 @@ private bool MoveTopHomeExtend ()
 
     private bool MoveUp ()
     {
-        if (CurrentRow > 0)
+        if (CurrentRow > 0 || (CurrentRow == 0 && CurrentRow < Viewport.Y))
         {
             if (_columnTrack == -1)
             {
                 _columnTrack = CurrentColumn;
             }
 
-            CurrentRow--;
+            if (CurrentRow > 0)
+            {
+                CurrentRow--;
+            }
 
-            if (CurrentRow < Viewport.Y)
+            if (CurrentRow < Viewport.Y || CurrentRow >= Viewport.Y + Viewport.Height)
             {
                 SetNeedsDraw ();
             }
@@ -393,6 +402,14 @@ private bool MoveWordLeft ()
             CurrentRow = newPos.Value.row;
         }
 
+        List<Cell> currentLine = GetCurrentLine ();
+        int cursorColumn = TextModel.CursorColumn (TextModel.CellsToStringList (currentLine), CurrentColumn, TabWidth, out _, out _);
+
+        if (CurrentRow < Viewport.Y || cursorColumn < Viewport.X || cursorColumn >= Viewport.X + Viewport.Width)
+        {
+            SetNeedsDraw ();
+        }
+
         DoNeededAction ();
 
         return true;
@@ -408,6 +425,14 @@ private bool MoveWordRight ()
             CurrentRow = newPos.Value.row;
         }
 
+        List<Cell> currentLine = GetCurrentLine ();
+        int cursorColumn = TextModel.CursorColumn (TextModel.CellsToStringList (currentLine), CurrentColumn, TabWidth, out _, out _);
+
+        if (CurrentRow >= Viewport.Y + Viewport.Height || cursorColumn >= Viewport.X + Viewport.Width || cursorColumn < Viewport.X)
+        {
+            SetNeedsDraw ();
+        }
+
         DoNeededAction ();
 
         return true;

Terminal.Gui/Views/TextInput/TextView/TextView.Scrolling.cs

@@ -115,11 +115,16 @@ private void AdjustViewport ()
             }
             need = true;
         }
-        else if (!_wordWrap && (CurrentColumn - Viewport.X + 1 > Viewport.Width || dSize.size + 1 >= Viewport.Width))
+        else if (!_wordWrap && (CurrentColumn - Viewport.X + 1 > Viewport.Width || dSize.size - Viewport.X + 1 >= Viewport.Width))
         {
             Viewport = Viewport with { X = TextModel.CalculateLeftColumn (line, Viewport.X, CurrentColumn, Viewport.Width, TabWidth) };
             need = true;
         }
+        else if (tSize.size - Viewport.X + 1 <= Viewport.Width)
+        {
+            Viewport = Viewport with { X = Math.Max (0, tSize.size - Viewport.Width + 1) };
+            need = true;
+        }
         else if ((_wordWrap && Viewport.X > 0) || (dSize.size < Viewport.Width && tSize.size < Viewport.Width))
         {
             if (Viewport.X > 0)
@@ -140,11 +145,6 @@ private void AdjustViewport ()
             Viewport = Viewport with { Y = Math.Min (Math.Max (CurrentRow - Viewport.Height + 1, 0), CurrentRow) };
             need = true;
         }
-        else if (!WordWrap && Viewport.Y > 0 && CurrentRow - Viewport.Height + 1 < Viewport.Y)
-        {
-            Viewport = Viewport with { Y = Math.Max (Viewport.Y - 1, 0) };
-            need = true;
-        }
 
         if (need)
         {

Terminal.Gui/Views/TextInput/TextView/TextView.Text.cs

@@ -558,23 +558,19 @@ private void InsertText (Key a, Attribute? attribute = null)
                 return;
             }
 
-            if (Used)
-            {
-                Insert (new Cell { Grapheme = grapheme, Attribute = attribute });
-                CurrentColumn++;
-            }
-            else
-            {
-                Insert (new Cell { Grapheme = grapheme, Attribute = attribute });
-                CurrentColumn++;
-            }
-            UpdateContentSize ();
+            Insert (new Cell { Grapheme = grapheme, Attribute = attribute });
+            CurrentColumn++;
+
+            // Text was inserted, so it's always needed to redraw and update content size if needed
+            SetNeedsDraw ();
+
             List<Cell> line = GetCurrentLine ();
-            (int size, int length) dSize = TextModel.DisplaySize (line, 0, CurrentColumn, true, TabWidth);
+            (int size, int length) dSize = TextModel.DisplaySize (line, 0, line.Count, true, TabWidth);
 
-            if (dSize.size + 1 - Viewport.X >= Viewport.Width)
+            if (_model.ShouldInvalidateMaxWidthCache (CurrentRow, true, dSize.size))
             {
-                SetNeedsDraw ();
+                _model.InvalidateMaxWidthCache ();
+                UpdateContentSize ();
             }
         }