Luccas/sd 2838 unify nested tables rendering

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

@@ -28,6 +28,17 @@ export {
 } from './engines/tables.js';
 
 export { effectiveTableCellSpacing } from './table-cell-spacing.js';
+export { computeTableFragmentHeight } from './table-fragment-height.js';
+export {
+  computeCellSliceContentHeight,
+  computeFullCellContentHeight,
+  createCellSliceCursor,
+  describeCellRenderBlocks,
+  getCellLines,
+  getEmbeddedRowLines,
+  type CellRenderBlock,
+  type CellSliceCursor,
+} from './table-cell-slice.js';
 
 // Table column rescaling (moved from layout-engine for cross-stage use)
 export { rescaleColumnWidths } from './table-column-rescale.js';

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

@@ -0,0 +1,132 @@
+import { describe, expect, it } from 'vitest';
+import type { ParagraphMeasure, TableCellMeasure, TableMeasure } from './index.js';
+import {
+  computeCellSliceContentHeight,
+  computeFullCellContentHeight,
+  createCellSliceCursor,
+  describeCellRenderBlocks,
+  getCellLines,
+} from './table-cell-slice.js';
+
+describe('table cell segment mapping', () => {
+  const makeParagraph = (lineCount: number): ParagraphMeasure => ({
+    kind: 'paragraph',
+    lines: Array.from({ length: lineCount }, () => ({
+      lineHeight: 20,
+      width: 100,
+      fromRun: 0,
+      fromChar: 0,
+      toRun: 0,
+      toChar: 1,
+      ascent: 14,
+      descent: 6,
+    })),
+    totalHeight: lineCount * 20,
+  });
+
+  const makeImage = (height: number) => ({
+    kind: 'image' as const,
+    width: 100,
+    height,
+  });
+
+  it('counts paragraph and positive-height object segments', () => {
+    const cell: TableCellMeasure = {
+      blocks: [makeParagraph(2), makeImage(50), makeImage(0), makeParagraph(3)],
+      width: 200,
+      height: 150,
+    };
+
+    expect(getCellLines(cell)).toHaveLength(6);
+  });
+
+  it('falls back to legacy single-paragraph cells', () => {
+    const cell: TableCellMeasure = {
+      paragraph: makeParagraph(3),
+      width: 200,
+      height: 60,
+    };
+
+    expect(getCellLines(cell)).toHaveLength(3);
+  });
+
+  it('expands nested table rows recursively', () => {
+    const innermostTable: TableMeasure = {
+      kind: 'table',
+      rows: [
+        { cells: [{ blocks: [makeParagraph(2)], width: 60, height: 40 }], height: 40 },
+        { cells: [{ blocks: [makeParagraph(3)], width: 60, height: 60 }], height: 60 },
+      ],
+      columnWidths: [60],
+      totalWidth: 60,
+      totalHeight: 100,
+    };
+    const middleTable: TableMeasure = {
+      kind: 'table',
+      rows: [{ cells: [{ blocks: [innermostTable], width: 80, height: 100 }], height: 100 }],
+      columnWidths: [80],
+      totalWidth: 80,
+      totalHeight: 100,
+    };
+    const outerTable: TableMeasure = {
+      kind: 'table',
+      rows: [{ cells: [{ blocks: [middleTable], width: 100, height: 100 }], height: 100 }],
+      columnWidths: [100],
+      totalWidth: 100,
+      totalHeight: 100,
+    };
+    const cell: TableCellMeasure = {
+      blocks: [outerTable],
+      width: 200,
+      height: 100,
+    };
+
+    expect(getCellLines(cell)).toHaveLength(2);
+  });
+
+  it('uses embedded table total height for full table slices', () => {
+    const nestedTable: TableMeasure = {
+      kind: 'table',
+      rows: [{ cells: [{ blocks: [makeParagraph(1)], width: 80, height: 20 }], height: 20 }],
+      columnWidths: [80],
+      totalWidth: 80,
+      totalHeight: 24,
+      cellSpacingPx: 2,
+    };
+    const cell: TableCellMeasure = {
+      blocks: [nestedTable],
+      width: 100,
+      height: 24,
+    };
+    const blocks = describeCellRenderBlocks(cell, undefined, { top: 0, bottom: 0 });
+
+    expect(computeCellSliceContentHeight(blocks, 0, 1)).toBe(24);
+    expect(computeFullCellContentHeight(cell, undefined, { top: 0, bottom: 0 })).toBe(24);
+    expect(createCellSliceCursor(blocks, 0).advanceLine(0)).toBe(24);
+    expect(createCellSliceCursor(blocks, 0).minSegmentCost(0)).toBe(24);
+  });
+
+  it('includes embedded table fragment spacing for partial row-boundary slices', () => {
+    const nestedTable: TableMeasure = {
+      kind: 'table',
+      rows: [
+        { cells: [{ blocks: [makeParagraph(1)], width: 80, height: 20 }], height: 20 },
+        { cells: [{ blocks: [makeParagraph(1)], width: 80, height: 20 }], height: 20 },
+      ],
+      columnWidths: [80],
+      totalWidth: 80,
+      totalHeight: 46,
+      cellSpacingPx: 2,
+    };
+    const cell: TableCellMeasure = {
+      blocks: [nestedTable],
+      width: 100,
+      height: 46,
+    };
+    const blocks = describeCellRenderBlocks(cell, undefined, { top: 0, bottom: 0 });
+
+    expect(computeCellSliceContentHeight(blocks, 0, 1)).toBe(24);
+    expect(createCellSliceCursor(blocks, 0).advanceLine(0)).toBe(24);
+    expect(createCellSliceCursor(blocks, 0).minSegmentCost(0)).toBe(24);
+  });
+});