[michaelstonis]

Summary

The table model had properties that layout and drawing ignored: TableStyle, TableCell.Background, TableCell.Border, and column/row spans. They now take effect. Tables that set none of them look the same as before.

• Layout: uses the table's border width and cell padding. A merged cell covers the columns and rows it spans, including the grid lines between them. If its content is taller than those rows, the last row it covers grows. A span that runs off the table, or into a slot another cell already covers, is cut short.
• Drawing: cell backgrounds are filled first. If a cell has no colour of its own and the table has a header row, the first row uses the header colour, or a faint tint if none is set. Each shared border is drawn once, at the wider of the two cells' widths. No border line is drawn through a merged cell, and covered cells aren't drawn.
• Tapping, the caret, Tab and resizing:
  • Tapping inside the area of a merged cell lands in that cell.
  • The caret is placed relative to the merged cell.
  • Tab and Shift+Tab skip the cells a merge covers.
  • Column and row resizing use the table's border width.
• New public API:
  • TableLayoutBlock: BorderWidth, BorderColor, per-slot CellInfo, GetCellBounds, GetOwningCell, GetColumnX and GetRowY.
  • TableBlock.GetSpanAnchor.

Default change: TableStyle.BorderColor used to default to black, but tables were always drawn in grey (160,160,160). Its default is now that grey, so existing tables look the same now that the property is used. This is listed under Changed in the CHANGELOG.

Testing

• 23 new tests in TableStylingTests:
  • layout sizes, with the default style and a custom one;
  • merged-cell geometry, row growth, and spans that are cut short;
  • tapping into covered cells and the caret in a merged cell;
  • exact fill rectangles and colours for the grid, header row, cell background and per-cell border;
  • inner lines and covered-cell text not being drawn;
  • Tab skipping covered cells;
  • HTML export still writing colspan/rowspan.
• Core.Tests pass (817) and SkiaSharp.Tests pass (29). The SkiaSharp Release build has 0 warnings, and the MAUI shared code compiles cleanly.

Not included

• Cell borders always use the table's border colour; the model has no per-cell colour.
• Header rows get a background colour but not bold text.
• After changing the style of a table that's already on screen, call NotifyChanged. The docs say so.

Checklist

• CHANGELOG entries under Unreleased → Added and Changed
• docs/tables.md updated

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Generated by Claude Code

[Copilot]

🟡 Changes recommended

Merged-cell interaction bugs, border overflow, and quadratic Tab traversal remain unresolved.

7 open issues

• Normalize stored positions to visible merged-cell anchors · New
• Pass the terminal merged slot to table-boundary handling · New
• Reuse the ownership map to avoid O(N²) merged-cell traversal · New
• Inset the outer bottom border within the table height · New
• Inset the outer right border within the table edge · New
• Ignore hidden column boundaries during resizing · New
• Ignore hidden row boundaries during resizing · New

What changed in this PR

Makes existing table styling and merged-cell properties affect the editor’s layout, rendering, and interaction.

Changes:

• Renders table styles, cell backgrounds, borders, and merged cells.
• Updates hit-testing, caret placement, Tab navigation, and resize geometry.
• Adds regression tests and documents behavior and defaults.

File	Description
tests/​MintedTextEditor.Core.Tests/​TableStylingTests.cs	Adds styling and merged-cell tests.
src/​MintedTextEditor.Maui/​MintedEditorView.cs	Uses styled border widths for resizing.
src/​MintedTextEditor.Core/​Rendering/​DocumentRenderer.cs	Draws backgrounds, merged content, and shared borders.
src/​MintedTextEditor.Core/​Layout/​TextLayoutEngine.cs	Applies styles and calculates merged geometry.
src/​MintedTextEditor.Core/​Layout/​TableLayoutBlock.cs	Exposes cell ownership, bounds, and styling.
src/​MintedTextEditor.Core/​Input/​EditorInputController.cs	Skips covered cells during Tab navigation.
src/​MintedTextEditor.Core/​Input/​DocumentHitTester.cs	Resolves taps to merged-cell anchors.
src/​MintedTextEditor.Core/​Editing/​CaretRenderer.cs	Positions the caret relative to merged cells.
src/​MintedTextEditor.Core/​Document/​TableStyle.cs	Defines rendering defaults and documents styling.
src/​MintedTextEditor.Core/​Document/​TableCell.cs	Clarifies decoration and merge documentation.
src/​MintedTextEditor.Core/​Document/​TableBlock.cs	Adds span ownership and clamping.
docs/​tables.md	Documents styling and merged-cell behavior.
CHANGELOG.md	Records features and the border-color default change.

_{Review effort: Balanced}