Make a text container's width in columns the line width of its snippet

CHANGELOG.md

@@ -29,6 +29,12 @@ Plain text now comes last in the snippet format order, so pasted DAX, SQL, or KQ
 as code. A bare word or a number still pastes as a note. An order you chose in
 Preferences is kept; a language added by an update joins it in front of Plain text.
 
+### A snippet's width is its line width
+Drag a text container's right edge, or hold **Shift** on its corner handle, to change its
+width in columns; the handle shows the count, and a plain drag of the corner still scales.
+**F6** wraps DAX to that width. A new container is 65 columns wide, where the DAX
+formatter wraps.
+
 ## 1.3.0 - 3 September 2026
 
 ### Export a board to PowerPoint

README.md

@@ -199,7 +199,8 @@ Use **Copy settings** after finding a useful combination so the exact values can
 | F2 | Edit the selected text container, or rename the selected frame |
 | View > Frame | Add a frame the size of the screen: a slide drawn on the board, selected by its edge or its tab, which Export takes as it is |
 | Language chip | Choose Plain text, DAX, or SQL Server on a selected text container |
-| F6 | Format DAX, SQL, or KQL on the selected text container. In F2, formats in place |
+| F6 | Format DAX, SQL, or KQL on the selected text container; DAX wraps to the container's columns. In F2, formats in place |
+| Drag right edge, or Shift + drag handle | Change a text container's width in columns and reflow it; the handle shows the count. A plain drag of the corner scales it |
 | Ctrl+Enter | Commit the F2 edit, including an F6 format done in that session, and return to display mode |
 | Escape | Cancel the active text edit, close the command strip, or leave full screen or canvas only |
 | Ctrl+S / Ctrl+O | Save / open a board |

docs/decisions.md

@@ -684,6 +684,37 @@ Two things were changed together, and the second is what makes the first safe:
 
 ---
 
+## 29. A text container's width in columns is the line width of its snippet
+
+**Implemented.**
+
+The DAX formatter wraps to a maximum line length; the SQL and KQL formatters break by
+structure and have no width at all. A "line width" setting shared by the three languages
+was therefore not added: it would be honoured by one of them. What every snippet already
+has is a width, and a text container wraps its lines at that width on screen, so the
+container's width in columns is the line width the reader sees. Two things were changed
+to make it the line width the formatter uses too:
+
+- **F6 formats DAX to the columns the container shows.** Columns are invariant under the
+  display-mode scaling, so this works whether or not the container has been enlarged for
+  the room. A new container is 65 columns wide, which is also the formatter's default, so
+  a pasted and formatted snippet has no visual wraps; before, the default width showed
+  about 58 columns and formatted DAX wrapped on screen at once.
+- **Shift while dragging the handle changes the width in columns** and reflows the text,
+  keeping the font size; the handle shows the count while dragging. A plain drag keeps
+  scaling the container like a picture. Replacing scaling with reflow was considered and
+  rejected: making a snippet bigger for the room is the resize a presenter needs, it is
+  what every other container does with the same gesture, and reflowing on a drag would
+  change line breaks while someone is only making space. Shift already means "constrain"
+  for strokes, so it reads as the narrower version of the gesture. The right edge of a text
+  container is the same width handle without the modifier: the cursor says so on hover,
+  which is what makes it discoverable, and the corner stays the scale handle.
+
+Structural switches for SQL and KQL, one column per line or one pipe per line, are the
+levers those languages have, and can come as yes-or-no settings when someone asks.
+
+---
+
 ## Open questions
 
 - arm64 is not built; add it if Surface devices matter for a pen application.

site/guide.html

@@ -697,7 +697,8 @@ <h3>Text, DAX, SQL, and KQL</h3>
     <p>Paste prefers an image when the clipboard has one, including a file SnagIt or another capture tool left on the clipboard. Paste plain text to create a selected text container.</p>
     <p>SVG counts as an image, whether the source application published it as SVG or the markup was simply copied as text — the output of a DAX SVG measure pastes as a picture, not as a snippet. Copying an SVG container puts the markup and a bitmap on the clipboard together, so an editor receives the source and a slide receives the picture.</p>
     <p><span class="ui">Help → Preferences</span> sets Snippet format order: paste tries those languages from top to bottom, and Plain text comes last, so DAX, SQL, and KQL are recognized while a bare word stays a note. Put Plain text first to keep every paste plain. Use the title-bar chip to change the language afterward.</p>
-    <p><kbd>F6</kbd> formats DAX, SQL, or KQL on the selected container, without entering edit mode. <kbd>F2</kbd> edits the container, and double-click still centers it and fits it to the canvas; inside an edit <kbd>F6</kbd> formats in place and <kbd>Ctrl</kbd><span class="plus">+</span><kbd>Enter</kbd> commits that format with the rest of the edit. SQL Server mode targets SQL Server 2025 T-SQL, keeps <code>GO</code> batch separators, and leaves an invalid script unchanged; KQL reads Kusto through Microsoft's own parser and likewise leaves an invalid query alone. <kbd>Escape</kbd> restores the previous text, language, and size.</p>
+    <p>A text container's width is its line width. Drag its right edge to change the width in columns and reflow the text; the handle shows the count. <kbd>Shift</kbd> on the corner handle does the same, and a plain drag of the corner scales the container like a picture. A new container is 65 columns wide, which is where the DAX formatter wraps.</p>
+    <p><kbd>F6</kbd> formats DAX, SQL, or KQL on the selected container, without entering edit mode, and wraps DAX to the container's columns. <kbd>F2</kbd> edits the container, and double-click still centers it and fits it to the canvas; inside an edit <kbd>F6</kbd> formats in place and <kbd>Ctrl</kbd><span class="plus">+</span><kbd>Enter</kbd> commits that format with the rest of the edit. SQL Server mode targets SQL Server 2025 T-SQL, keeps <code>GO</code> batch separators, and leaves an invalid script unchanged; KQL reads Kusto through Microsoft's own parser and likewise leaves an invalid query alone. <kbd>Escape</kbd> restores the previous text, language, and size.</p>
 
     <h3 id="liveview">LiveView</h3>
     <p><span class="ui">View → LiveView</span> captures a window or a display. The container behaves like an image: move, resize, frame, delete, undo.</p>

site/shortcuts.html

@@ -122,7 +122,8 @@ <h2><span class="secico" aria-hidden="true"><svg viewBox="0 0 24 24" fill="none"
       <div class="keyrow"><span><kbd>Ctrl</kbd><span class="plus">+</span><kbd>E</kbd></span><span class="act">Export the board to PowerPoint or PDF. Commits an active text edit first.</span></div>
       <div class="keyrow"><span><kbd>Delete</kbd></span><span class="act">Delete the selected container and its linked strokes.</span></div>
       <div class="keyrow"><span><kbd>F2</kbd></span><span class="act">Edit the selected text container, or rename the selected frame.</span></div>
-      <div class="keyrow"><span><kbd>F6</kbd></span><span class="act">Format DAX, SQL Server, or KQL on the selected text container. In <kbd>F2</kbd>, formats in place; <kbd>Ctrl</kbd><span class="plus">+</span><kbd>Enter</kbd> then commits.</span></div>
+      <div class="keyrow"><span><kbd>F6</kbd></span><span class="act">Format DAX, SQL Server, or KQL on the selected text container; DAX wraps to the container's columns. In <kbd>F2</kbd>, formats in place; <kbd>Ctrl</kbd><span class="plus">+</span><kbd>Enter</kbd> then commits.</span></div>
+      <div class="keyrow"><span><kbd>Shift</kbd><span class="plus">+</span><kbd class="gesture">Drag handle</kbd></span><span class="act">Change a text container's width in columns and reflow it; the handle shows the count. Dragging the container's right edge does the same. A plain drag of the corner scales it.</span></div>
       <div class="keyrow"><span><kbd>Ctrl</kbd><span class="plus">+</span><kbd>Enter</kbd></span><span class="act">Commit the F2 edit, including an F6 format done in that session, and return to display mode.</span></div>
       <div class="keyrow"><span><kbd>Escape</kbd></span><span class="act">Cancel the F2 edit (including an uncommitted F6), close the command strip, or leave full screen or canvas only.</span></div>
       <div class="keyrow"><span><kbd>Alt</kbd><span class="plus">+</span><kbd>L</kbd></span><span class="act">Laser pointer.</span></div>

src/SQLBI.Whiteboard/BoardSurface.cs

@@ -53,6 +53,12 @@ internal sealed class BoardSurface : FrameworkElement
     /// </summary>
     public bool DrawFrames { get; set; } = true;
 
+    /// <summary>
+    /// A word or two beside the resize handle while a gesture needs one, such
+    /// as the column count of a text container being reflowed.
+    /// </summary>
+    public string? HandleLabel { get; set; }
+
     /// <summary>
     /// The stroke the pen is drawing right now, before it is committed. Pen ink
     /// is collected here rather than by the InkCanvas, so the wet stroke is
@@ -311,7 +317,7 @@ private bool TryGetImage(
         }
     }
 
-    private static void DrawSelection(
+    private void DrawSelection(
         DrawingContext drawingContext,
         RectD bounds,
         Camera2D camera,
@@ -334,6 +340,21 @@ private static void DrawSelection(
                 7,
                 7);
         }
+
+        if (includeHandle && HandleLabel is { Length: > 0 } label)
+        {
+            var text = new FormattedText(
+                label,
+                System.Globalization.CultureInfo.CurrentUICulture,
+                FlowDirection.LeftToRight,
+                FrameTypeface,
+                12,
+                FrameTitleBrush,
+                VisualTreeHelper.GetDpi(this).PixelsPerDip);
+            var badge = new Rect(bottomRight.X + 12, bottomRight.Y - (text.Height / 2) - 3, text.Width + 12, text.Height + 6);
+            drawingContext.DrawRoundedRectangle(SelectionPen.Brush, null, badge, 4, 4);
+            drawingContext.DrawText(text, new Point(badge.Left + 6, badge.Top + 3));
+        }
     }
 
     private static Color ToColor(uint argb) => Color.FromArgb(

src/SQLBI.Whiteboard/MainWindow.xaml.cs

@@ -96,6 +96,7 @@ private enum PointerAction
     private InkStrokeObject[] _containerGestureLinkedCurrent = [];
     private PointD _containerGestureStartWorld;
     private bool _containerGestureIsResize;
+    private bool _containerGestureReflow;
     private TextBoardObject? _textEditBefore;
     private InkStrokeObject[] _textEditLinkedBefore = [];
     private RectD _textEditBounds;
@@ -2007,9 +2008,22 @@ private void BeginContainerGesture(PointD screenPoint)
             {
                 selected = existing;
                 _containerGestureIsResize = true;
+
+                // Shift on the handle of a text container changes its width in
+                // columns and reflows the text, keeping the size; a plain drag
+                // scales it like a picture, as it does every container.
+                _containerGestureReflow = existing is TextBoardObject &&
+                                          Keyboard.Modifiers.HasFlag(ModifierKeys.Shift);
             }
         }
 
+        if (!_containerGestureIsResize && FindTextContainerAtRightEdge(screenPoint) is { } edged)
+        {
+            selected = edged;
+            _containerGestureIsResize = true;
+            _containerGestureReflow = true;
+        }
+
         _selectedObjectId = selected?.Id;
         SceneSurface.SelectedObjectId = _selectedObjectId;
         if (selected is null)
@@ -2037,6 +2051,28 @@ private void UpdateContainerGesture(PointD worldPoint)
         }
 
         var bounds = _containerGestureBefore.Bounds;
+        if (_containerGestureReflow && _containerGestureBefore is TextBoardObject reflowed)
+        {
+            double pixelsPerDip = VisualTreeHelper.GetDpi(SceneSurface).PixelsPerDip;
+            double width = Math.Max(
+                TextContainerVisual.MinimumWidth * reflowed.VisualScale,
+                worldPoint.X - bounds.Left);
+            double height = TextContainerVisual.MeasureDesiredHeight(
+                reflowed.Text,
+                width,
+                reflowed.VisualScale,
+                pixelsPerDip,
+                reflowed.LanguageId);
+            bounds = new RectD(bounds.Left, bounds.Top, width, height);
+            SceneSurface.HandleLabel = TextContainerVisual.ColumnsFor(width, reflowed.VisualScale, reflowed.LanguageId, pixelsPerDip) + " columns";
+            _containerGestureCurrent = reflowed with { Bounds = bounds };
+            _containerGestureLinkedCurrent = _containerGestureLinkedBefore
+                .Select(stroke => stroke.TransformWithContainer(_containerGestureBefore.Bounds, bounds))
+                .ToArray();
+            _document.ReplaceObjects([_containerGestureCurrent, .. _containerGestureLinkedCurrent]);
+            return;
+        }
+
         if (_containerGestureIsResize)
         {
             var minimumWorldSize = 32 / _camera.Zoom;
@@ -2094,6 +2130,12 @@ private void ResetContainerGesture()
         _containerGestureLinkedBefore = [];
         _containerGestureLinkedCurrent = [];
         _containerGestureIsResize = false;
+        _containerGestureReflow = false;
+        if (SceneSurface.HandleLabel is not null)
+        {
+            SceneSurface.HandleLabel = null;
+            SceneSurface.InvalidateVisual();
+        }
     }
 
     private static BoardObject WithBounds(BoardObject item, RectD bounds) => item switch
@@ -2441,8 +2483,13 @@ private void FormatTextEdit()
         }
 
         ITextLanguageService language = TextLanguageRegistry.Resolve(_textEditLanguageId);
+        int editColumns = TextContainerVisual.ColumnsFor(
+            _textEditBounds.Width,
+            _textEditBefore.VisualScale,
+            _textEditLanguageId,
+            VisualTreeHelper.GetDpi(SceneSurface).PixelsPerDip);
         if (!language.CanFormat ||
-            !language.TryFormat(TextEditor.Text, out string formatted) ||
+            !language.TryFormat(TextEditor.Text, editColumns, out string formatted) ||
             string.Equals(TextEditor.Text, formatted, StringComparison.Ordinal))
         {
             return;
@@ -2469,9 +2516,12 @@ private void FormatSelectedText()
             return;
         }
 
+        // Formatted to the columns the container shows, so the lines fit it:
+        // the container's width is the line width of the snippet.
         ITextLanguageService language = TextLanguageRegistry.Resolve(textObject.LanguageId);
+        int columns = TextContainerVisual.ColumnsFor(textObject, VisualTreeHelper.GetDpi(SceneSurface).PixelsPerDip);
         if (!language.CanFormat ||
-            !language.TryFormat(textObject.Text, out string formatted) ||
+            !language.TryFormat(textObject.Text, columns, out string formatted) ||
             string.Equals(textObject.Text, formatted, StringComparison.Ordinal))
         {
             return;
@@ -3348,7 +3398,8 @@ private void UpdateSelectHover(PointD screen)
             return;
         }
 
-        var container = _document.HitTestTopContainer(_camera.ScreenToWorld(screen), _camera.Zoom);
+        var container = _document.HitTestTopContainer(_camera.ScreenToWorld(screen), _camera.Zoom)
+            ?? FindTextContainerAtRightEdge(screen);
         var hoveredId = container?.Id;
         if (SceneSurface.HoveredObjectId == hoveredId)
         {
@@ -3366,11 +3417,45 @@ private Cursor SelectCursorAt(PointD screen)
             return Cursors.SizeNWSE;
         }
 
+        if (FindTextContainerAtRightEdge(screen) is not null)
+        {
+            return Cursors.SizeWE;
+        }
+
         return _document.HitTestTopContainer(_camera.ScreenToWorld(screen), _camera.Zoom) is null
             ? Cursors.Arrow
             : Cursors.SizeAll;
     }
 
+    /// <summary>
+    /// The right edge of a text container is its width handle: dragging it
+    /// changes the columns and reflows, as Shift on the corner does, but with
+    /// a cursor that says so on hover. The corner itself stays the scale handle.
+    /// </summary>
+    private const double EdgeHandleTolerance = 8;
+
+    private TextBoardObject? FindTextContainerAtRightEdge(PointD screen)
+    {
+        if (IsOverResizeHandle(screen))
+        {
+            return null;
+        }
+
+        foreach (var text in _document.Objects.OfType<TextBoardObject>().OrderByDescending(item => item.ZIndex))
+        {
+            var topRight = _camera.WorldToScreen(new PointD(text.Bounds.Right, text.Bounds.Top));
+            var bottom = _camera.WorldToScreen(new PointD(text.Bounds.Right, text.Bounds.Bottom)).Y;
+            if (Math.Abs(screen.X - topRight.X) <= EdgeHandleTolerance &&
+                screen.Y >= topRight.Y - EdgeHandleTolerance &&
+                screen.Y <= bottom - 16)
+            {
+                return text;
+            }
+        }
+
+        return null;
+    }
+
     private bool IsOverResizeHandle(PointD screen)
     {
         if (_selectedObjectId is not Guid existingId ||
@@ -4064,15 +4149,16 @@ private void AddText(
         }
 
         double visibleWidth = _camera.VisibleWorldBounds.Width;
+        double pixelsPerDip = VisualTreeHelper.GetDpi(SceneSurface).PixelsPerDip;
         double width = Math.Min(
-            TextContainerVisual.DefaultWidth,
+            TextContainerVisual.DefaultWidth(pixelsPerDip),
             Math.Max(320, visibleWidth * 0.7));
         string resolvedLanguageId = TextLanguageIds.Normalize(languageId);
         double height = TextContainerVisual.MeasureDesiredHeight(
             text,
             width,
             1,
-            VisualTreeHelper.GetDpi(SceneSurface).PixelsPerDip,
+            pixelsPerDip,
             resolvedLanguageId);
         PointD center = worldCenter ?? _camera.Center;
         var textObject = new TextBoardObject(
@@ -4942,7 +5028,7 @@ private void ApplyImport(ImportDocument imported, PointD originTopLeft, bool rec
                 }
 
                 var width = Math.Min(
-                    TextContainerVisual.DefaultWidth,
+                    TextContainerVisual.DefaultWidth(dpi),
                     Math.Max(320, _camera.VisibleWorldBounds.Width * 0.7));
                 var height = TextContainerVisual.MeasureDesiredHeight(text, width, 1, dpi);
                 sizes.Add((width, height, item.StartNewRow));