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Merged
caio-pizzol merged 1 commit into from
Apr 14, 2026
Merged

feat(math): implement m:m matrix converter #2753

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1 change: 1 addition & 0 deletions packages/layout-engine/painters/dom/src/features/math/converters/index.ts
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Expand Up @@ -23,3 +23,4 @@ export { convertUpperLimit } from './upper-limit.js';
export { convertNary } from './nary.js';
export { convertPhantom } from './phantom.js';
export { convertGroupCharacter } from './group-character.js';
export { convertMatrix } from './matrix.js';
73 changes: 73 additions & 0 deletions packages/layout-engine/painters/dom/src/features/math/converters/matrix.ts
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@@ -0,0 +1,73 @@
import type { MathObjectConverter, OmmlJsonNode } from '../types.js';

const MATHML_NS = 'http://www.w3.org/1998/Math/MathML';

/** Visual placeholder for empty matrix cells when m:plcHide is off (§22.1.2.83). */
const EMPTY_CELL_PLACEHOLDER = '\u25A1'; // WHITE SQUARE

/** True when the given m:plcHide element expresses "hide placeholders". */
function isPlaceholderHidden(plcHide: OmmlJsonNode | undefined): boolean {
if (!plcHide) return false;
const val = plcHide.attributes?.['m:val'];
// Per §22.1.2.83: presence without @m:val means placeholders are hidden.
if (val === undefined) return true;
return val === '1' || val === 'true';
}

/**
* Convert m:m (matrix) to MathML <mtable>.
*
* OMML structure:
* m:m → m:mPr (optional: mcs/mcJc/baseJc/plcHide — only plcHide applied), m:mr* (rows)
* m:mr → m:e* (cells; empty m:e creates a positional gap per §22.1.2.32)
*
* MathML output:
* <mtable>
* <mtr>
* <mtd> <mrow>cell-content</mrow> </mtd>
* ...
* </mtr>
* ...
* </mtable>
*
* Empty cells render a U+25A1 placeholder by default (§22.1.2.83 plcHide="0").
* When m:plcHide is present with val "1"/"true" or no val, the placeholder is suppressed.
*
* @spec ECMA-376 §22.1.2.60
*/
export const convertMatrix: MathObjectConverter = (node, doc, convertChildren) => {
const elements = node.elements ?? [];
const rows = elements.filter((e) => e.name === 'm:mr');

const matrixProps = elements.find((e) => e.name === 'm:mPr');
const plcHide = matrixProps?.elements?.find((e) => e.name === 'm:plcHide');
const hidePlaceholders = isPlaceholderHidden(plcHide);

const mtable = doc.createElementNS(MATHML_NS, 'mtable');

for (const row of rows) {
const mtr = doc.createElementNS(MATHML_NS, 'mtr');
const cells = row.elements?.filter((e) => e.name === 'm:e') ?? [];

for (const cell of cells) {
const mtd = doc.createElementNS(MATHML_NS, 'mtd');
const mrow = doc.createElementNS(MATHML_NS, 'mrow');
const fragment = convertChildren(cell.elements ?? []);

if (fragment.childNodes.length === 0 && !hidePlaceholders) {
const placeholder = doc.createElementNS(MATHML_NS, 'mi');
placeholder.textContent = EMPTY_CELL_PLACEHOLDER;
mrow.appendChild(placeholder);
} else {
mrow.appendChild(fragment);
}

mtd.appendChild(mrow);
mtr.appendChild(mtd);
}

mtable.appendChild(mtr);
}

return mtable.childNodes.length > 0 ? mtable : null;
};
309 changes: 309 additions & 0 deletions packages/layout-engine/painters/dom/src/features/math/omml-to-mathml.test.ts
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Expand Up @@ -3620,3 +3620,312 @@ describe('m:groupChr converter', () => {
});
});
});

describe('m:m converter', () => {
it('converts 2x2 matrix to <mtable> with <mtr> and <mtd>', () => {
const omml = {
name: 'm:oMath',
elements: [
{
name: 'm:m',
elements: [
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'a' }] }] }],
},
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'b' }] }] }],
},
],
},
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'c' }] }] }],
},
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'd' }] }] }],
},
],
},
],
},
],
};
const result = convertOmmlToMathml(omml, doc);
expect(result).not.toBeNull();
const mtable = result!.querySelector('mtable');
expect(mtable).not.toBeNull();
const rows = mtable!.querySelectorAll('mtr');
expect(rows.length).toBe(2);
const cells = mtable!.querySelectorAll('mtd');
expect(cells.length).toBe(4);
expect(cells[0]!.textContent).toBe('a');
expect(cells[1]!.textContent).toBe('b');
expect(cells[2]!.textContent).toBe('c');
expect(cells[3]!.textContent).toBe('d');
});

it('returns null for empty matrix', () => {
const omml = {
name: 'm:oMath',
elements: [{ name: 'm:m', elements: [] }],
};
const result = convertOmmlToMathml(omml, doc);
expect(result).toBeNull();
});

it('converts 1x3 row vector', () => {
const omml = {
name: 'm:oMath',
elements: [
{
name: 'm:m',
elements: [
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: '1' }] }] }],
},
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: '2' }] }] }],
},
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: '3' }] }] }],
},
],
},
],
},
],
};
const result = convertOmmlToMathml(omml, doc);
const mtable = result!.querySelector('mtable');
expect(mtable).not.toBeNull();
const rows = mtable!.querySelectorAll('mtr');
expect(rows.length).toBe(1);
const cells = mtable!.querySelectorAll('mtd');
expect(cells.length).toBe(3);
});

it('wraps each cell content in <mrow> inside <mtd>', () => {
const omml = {
name: 'm:oMath',
elements: [
{
name: 'm:m',
elements: [
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [
{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'x' }] }] },
{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: '+' }] }] },
{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'y' }] }] },
],
},
],
},
],
},
],
};
const result = convertOmmlToMathml(omml, doc);
const mtd = result!.querySelector('mtd');
expect(mtd).not.toBeNull();
// Cell content sits under an <mrow>, not as direct <mtd> siblings.
expect(mtd!.children.length).toBe(1);
expect(mtd!.firstElementChild!.localName).toBe('mrow');
expect(mtd!.textContent).toBe('x+y');
});

it('preserves nested math objects in cells (fraction, superscript)', () => {
const omml = {
name: 'm:oMath',
elements: [
{
name: 'm:m',
elements: [
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [
{
name: 'm:f',
elements: [
{
name: 'm:num',
elements: [
{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'a' }] }] },
],
},
{
name: 'm:den',
elements: [
{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'b' }] }] },
],
},
],
},
],
},
{
name: 'm:e',
elements: [
{
name: 'm:sSup',
elements: [
{
name: 'm:e',
elements: [
{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'z' }] }] },
],
},
{
name: 'm:sup',
elements: [
{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: '2' }] }] },
],
},
],
},
],
},
],
},
],
},
],
};
const result = convertOmmlToMathml(omml, doc);
const mtable = result!.querySelector('mtable');
expect(mtable!.querySelector('mtd mfrac')).not.toBeNull();
expect(mtable!.querySelector('mtd msup')).not.toBeNull();
});

it('renders a placeholder in empty <m:e> cells by default (§22.1.2.83 plcHide="0")', () => {
const omml = {
name: 'm:oMath',
elements: [
{
name: 'm:m',
elements: [
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'a' }] }] }],
},
{ name: 'm:e' },
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'c' }] }] }],
},
],
},
],
},
],
};
const result = convertOmmlToMathml(omml, doc);
const cells = result!.querySelectorAll('mtd');
expect(cells.length).toBe(3);
expect(cells[0]!.textContent).toBe('a');
expect(cells[1]!.textContent).toBe('\u25A1');
expect(cells[2]!.textContent).toBe('c');
});

it('hides empty-cell placeholders when m:plcHide is set (§22.1.2.83)', () => {
const omml = {
name: 'm:oMath',
elements: [
{
name: 'm:m',
elements: [
{ name: 'm:mPr', elements: [{ name: 'm:plcHide', attributes: { 'm:val': '1' } }] },
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'a' }] }] }],
},
{ name: 'm:e' },
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'c' }] }] }],
},
],
},
],
},
],
};
const result = convertOmmlToMathml(omml, doc);
const cells = result!.querySelectorAll('mtd');
expect(cells.length).toBe(3);
expect(cells[1]!.textContent).toBe('');
});

it('ignores m:mPr properties element', () => {
const omml = {
name: 'm:oMath',
elements: [
{
name: 'm:m',
elements: [
{
name: 'm:mPr',
elements: [
{
name: 'm:mcs',
elements: [
{
name: 'm:mc',
elements: [{ name: 'm:mcPr', elements: [{ name: 'm:count', attributes: { 'm:val': '2' } }] }],
},
],
},
],
},
{
name: 'm:mr',
elements: [
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'a' }] }] }],
},
{
name: 'm:e',
elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'b' }] }] }],
},
],
},
],
},
],
};
const result = convertOmmlToMathml(omml, doc);
const mtable = result!.querySelector('mtable');
expect(mtable).not.toBeNull();
const cells = mtable!.querySelectorAll('mtd');
expect(cells.length).toBe(2);
expect(mtable!.textContent).toBe('ab');
});
});
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