fix: before paragraph spacing inside table cells (#1842)

* fix: before paragraph spacing inside table cells

* fix: remove extra code in layout bridge

* fix: extend test cases and remove unused code

* fix: failing test

* fix: consider padding for the first block in line

* fix: add helper/ improve test coverage

* refactor: clean up DX and add spacing.after test coverage

- Export mock-data constants directly, removing unnecessary _EXPORT aliases
- Use cleaner (block as ParagraphBlock) cast pattern in layout-bridge
- Add spacing.after absorption test for selectionToRects (two-paragraph cell)

---------

Co-authored-by: Caio Pizzol <caio@harbourshare.com>

Author: VladaHarbour

packages/layout-engine/contracts/src/index.ts

@@ -7,6 +7,8 @@ export type { TabStop };
 // Export table contracts
 export { OOXML_PCT_DIVISOR, type TableWidthAttr, type TableColumnSpec } from './engines/tables.js';
 
+export { effectiveTableCellSpacing } from './table-cell-spacing.js';
+
 // Export justify utilities
 export {
   shouldApplyJustify,

packages/layout-engine/contracts/src/table-cell-spacing.test.ts

@@ -0,0 +1,26 @@
+import { describe, expect, it } from 'vitest';
+import { effectiveTableCellSpacing } from './table-cell-spacing.js';
+
+describe('effectiveTableCellSpacing', () => {
+  it('returns 0 when spacing is undefined', () => {
+    expect(effectiveTableCellSpacing(undefined, false, 0)).toBe(0);
+    expect(effectiveTableCellSpacing(undefined, true, 10)).toBe(0);
+  });
+
+  it('returns 0 when spacing is <= 0', () => {
+    expect(effectiveTableCellSpacing(0, false, 0)).toBe(0);
+    expect(effectiveTableCellSpacing(-5, true, 0)).toBe(0);
+  });
+
+  it('returns full spacing when not at boundary', () => {
+    expect(effectiveTableCellSpacing(20, false, 10)).toBe(20);
+    expect(effectiveTableCellSpacing(20, false, 0)).toBe(20);
+  });
+
+  it('returns excess over padding when at boundary', () => {
+    expect(effectiveTableCellSpacing(20, true, 10)).toBe(10);
+    expect(effectiveTableCellSpacing(20, true, 0)).toBe(20);
+    expect(effectiveTableCellSpacing(10, true, 10)).toBe(0);
+    expect(effectiveTableCellSpacing(5, true, 10)).toBe(0);
+  });
+});

packages/layout-engine/contracts/src/table-cell-spacing.ts

@@ -0,0 +1,17 @@
+/**
+ * Effective paragraph spacing in table cells.
+ *
+ * Word absorbs the first paragraph's spacing.before into the cell's top padding,
+ * and the last paragraph's spacing.after into the cell's bottom padding.
+ * This helper returns the amount to add to height/position: at a boundary,
+ * only the excess of spacing over padding; otherwise the full spacing.
+ *
+ * Use for both spacing.before (isBoundary = first block, padding = paddingTop)
+ * and spacing.after (isBoundary = last block, padding = paddingBottom).
+ */
+export function effectiveTableCellSpacing(spacing: number | undefined, isBoundary: boolean, padding: number): number {
+  if (typeof spacing !== 'number' || spacing <= 0) {
+    return 0;
+  }
+  return isBoundary ? Math.max(0, spacing - padding) : spacing;
+}

packages/layout-engine/layout-bridge/src/index.ts

@@ -13,7 +13,7 @@ import type {
   ParagraphBlock,
   ParagraphMeasure,
 } from '@superdoc/contracts';
-import { computeLinePmRange as computeLinePmRangeUnified } from '@superdoc/contracts';
+import { computeLinePmRange as computeLinePmRangeUnified, effectiveTableCellSpacing } from '@superdoc/contracts';
 import { charOffsetToPm, findCharacterAtX, measureCharacterX } from './text-measurement.js';
 import { clickToPositionDom, findPageElement } from './dom-mapping.js';
 import {
@@ -1695,10 +1695,12 @@ export function selectionToRects(
                 if (typeof totalHeight === 'number' && totalHeight > height) {
                   height = totalHeight;
                 }
-                const spacingAfter = (paraBlock.attrs as { spacing?: { after?: number } } | undefined)?.spacing?.after;
-                if (typeof spacingAfter === 'number' && spacingAfter > 0) {
-                  height += spacingAfter;
-                }
+                const isFirstBlock = i === 0;
+                const isLastBlock = i === cellBlocks.length - 1;
+                const spacingBefore = (paraBlock as ParagraphBlock).attrs?.spacing?.before;
+                height += effectiveTableCellSpacing(spacingBefore, isFirstBlock, padding.top);
+                const spacingAfter = (paraBlock as ParagraphBlock).attrs?.spacing?.after;
+                height += effectiveTableCellSpacing(spacingAfter, isLastBlock, padding.bottom);
               }
 
               renderedBlocks.push({ block: paraBlock, measure: paraMeasure, startLine, endLine, height });
@@ -1718,7 +1720,7 @@ export function selectionToRects(
 
             let blockTopCursor = padding.top + verticalOffset;
 
-            renderedBlocks.forEach((info) => {
+            renderedBlocks.forEach((info, blockIndex) => {
               const paragraphMarkerWidth = info.measure.marker?.markerWidth ?? 0;
               // List items in table cells are also rendered with left alignment
               const cellIsListItem = isListItem(paragraphMarkerWidth, info.block);
@@ -1731,6 +1733,11 @@ export function selectionToRects(
 
               const intersectingLines = findLinesIntersectingRange(info.block, info.measure, from, to);
 
+              // Match renderer: spacing.before is only applied when rendering from the start of the block (startLine === 0).
+              const rawSpacingBefore = (info.block as ParagraphBlock).attrs?.spacing?.before;
+              const effectiveSpacingBeforePx =
+                info.startLine === 0 ? effectiveTableCellSpacing(rawSpacingBefore, blockIndex === 0, padding.top) : 0;
+
               intersectingLines.forEach(({ line, index }) => {
                 if (index < info.startLine || index >= info.endLine) {
                   return;
@@ -1768,7 +1775,8 @@ export function selectionToRects(
                 );
                 const lineOffset =
                   lineHeightBeforeIndex(info.measure, index) - lineHeightBeforeIndex(info.measure, info.startLine);
-                const rectY = fragment.y + contentOffsetY + rowOffset + blockTopCursor + lineOffset;
+                const rectY =
+                  fragment.y + contentOffsetY + rowOffset + blockTopCursor + effectiveSpacingBeforePx + lineOffset;
 
                 rects.push({
                   x: rectX,