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Abdeltotocaio-pizzol
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feat(math): implement m:phant phantom converter (#2749)
* feat(math): implement m:phant phantom converter (closes #2608) Made-with: Cursor * fix(math): parse full ST_OnOff values in phantom converter Made-with: Cursor * fix(math): treat bare m:show element as visible in phantom converter Made-with: Cursor * fix(math): render phantom as visible when m:show is omitted Per ECMA-376 §22.1.2.96, when <m:show> is absent from <m:phantPr> the base content should be shown. The previous check only handled bare and truthy-val variants, so a missing element was treated as hidden — breaking the most common phantom pattern (zeroing a dimension without hiding content). Adds unit coverage for the explicit-hide case and zeroed-dimension-only case, plus a behavior test loading a 12-case fixture that walks every m:phantPr configuration in the spec (show absent/bare/val=0/1/true/false, each zero flag alone and combined, m:transp passthrough). --------- Co-authored-by: Caio Pizzol <caio@harbourshare.com>
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Lines changed: 407 additions & 1 deletion

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‎packages/layout-engine/painters/dom/src/features/math/converters/index.ts‎

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@@ -21,3 +21,4 @@ export { convertRadical } from './radical.js';
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export { convertLowerLimit } from './lower-limit.js';
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export { convertUpperLimit } from './upper-limit.js';
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export { convertNary } from './nary.js';
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export { convertPhantom } from './phantom.js';

‎packages/layout-engine/painters/dom/src/features/math/converters/phantom.ts‎

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@@ -0,0 +1,62 @@
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import type { MathObjectConverter } from '../types.js';
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const MATHML_NS = 'http://www.w3.org/1998/Math/MathML';
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/**
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* Convert m:phant (phantom) to MathML <mphantom> or styled <mpadded>.
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*
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* OMML structure:
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* m:phant → m:phantPr (optional: m:show, m:zeroWid, m:zeroAsc, m:zeroDesc), m:e (content)
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*
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* MathML output:
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* Full phantom (default): <mphantom> content </mphantom>
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* Visible with zeroed dimensions: <mpadded> with width/height/depth="0"
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*
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* A phantom reserves the space its content would occupy but renders invisibly.
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* Property flags can zero-out individual dimensions or force visibility.
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*
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* @spec ECMA-376 §22.1.2.81
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*/
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export const convertPhantom: MathObjectConverter = (node, doc, convertChildren) => {
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const elements = node.elements ?? [];
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const phantPr = elements.find((e) => e.name === 'm:phantPr');
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const base = elements.find((e) => e.name === 'm:e');
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const show = phantPr?.elements?.find((e) => e.name === 'm:show');
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const zeroWid = phantPr?.elements?.find((e) => e.name === 'm:zeroWid');
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const zeroAsc = phantPr?.elements?.find((e) => e.name === 'm:zeroAsc');
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const zeroDesc = phantPr?.elements?.find((e) => e.name === 'm:zeroDesc');
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/** OOXML ST_OnOff true values. */
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const isOnOffTrue = (val?: string) => val === '1' || val === 'on' || val === 'true';
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// Per ECMA-376 §22.1.2.96: when m:show is omitted, the base is shown.
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const isVisible = show == null || !show.attributes || isOnOffTrue(show.attributes['m:val']);
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const hasZeroDimension = zeroWid || zeroAsc || zeroDesc;
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const content = convertChildren(base?.elements ?? []);
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if (!isVisible && !hasZeroDimension) {
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const mphantom = doc.createElementNS(MATHML_NS, 'mphantom');
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mphantom.appendChild(content);
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return mphantom;
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}
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const mpadded = doc.createElementNS(MATHML_NS, 'mpadded');
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const isZeroVal = (el?: typeof zeroWid) => el && (isOnOffTrue(el.attributes?.['m:val']) || !el.attributes);
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if (isZeroVal(zeroWid)) mpadded.setAttribute('width', '0');
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if (isZeroVal(zeroAsc)) mpadded.setAttribute('height', '0');
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if (isZeroVal(zeroDesc)) mpadded.setAttribute('depth', '0');
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if (!isVisible) {
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const mphantom = doc.createElementNS(MATHML_NS, 'mphantom');
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mphantom.appendChild(content);
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mpadded.appendChild(mphantom);
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} else {
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mpadded.appendChild(content);
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}
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return mpadded;
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};

‎packages/layout-engine/painters/dom/src/features/math/omml-to-mathml.test.ts‎

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@@ -3292,3 +3292,164 @@ describe('m:nary converter', () => {
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expect(mo!.textContent).toBe('');
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});
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});
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describe('m:phant converter', () => {
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it('renders phantom with no properties as visible (m:show default)', () => {
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const omml = {
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name: 'm:oMath',
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elements: [
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{
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name: 'm:phant',
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elements: [
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{
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name: 'm:e',
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elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'x' }] }] }],
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},
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],
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},
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],
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};
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const result = convertOmmlToMathml(omml, doc);
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expect(result).not.toBeNull();
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expect(result!.querySelector('mphantom')).toBeNull();
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expect(result!.textContent).toBe('x');
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});
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it('hides content when m:show has m:val="0"', () => {
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const omml = {
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name: 'm:oMath',
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elements: [
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{
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name: 'm:phant',
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elements: [
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{
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name: 'm:phantPr',
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elements: [{ name: 'm:show', attributes: { 'm:val': '0' } }],
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},
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{
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name: 'm:e',
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elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'x' }] }] }],
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},
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],
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},
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],
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};
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const result = convertOmmlToMathml(omml, doc);
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const mphantom = result!.querySelector('mphantom');
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expect(mphantom).not.toBeNull();
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expect(mphantom!.textContent).toBe('x');
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});
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it('converts visible phantom with zeroed width to <mpadded width="0">', () => {
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const omml = {
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name: 'm:oMath',
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elements: [
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{
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name: 'm:phant',
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elements: [
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{
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name: 'm:phantPr',
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elements: [
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{ name: 'm:show', attributes: { 'm:val': '1' } },
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{ name: 'm:zeroWid', attributes: { 'm:val': '1' } },
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],
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},
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{
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name: 'm:e',
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elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'y' }] }] }],
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},
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],
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},
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],
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};
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const result = convertOmmlToMathml(omml, doc);
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const mpadded = result!.querySelector('mpadded');
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expect(mpadded).not.toBeNull();
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expect(mpadded!.getAttribute('width')).toBe('0');
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expect(mpadded!.textContent).toBe('y');
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});
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it('treats bare <m:show/> (no attributes) as visible', () => {
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const omml = {
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name: 'm:oMath',
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elements: [
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{
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name: 'm:phant',
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elements: [
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{
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name: 'm:phantPr',
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elements: [{ name: 'm:show' }, { name: 'm:zeroWid', attributes: { 'm:val': '1' } }],
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},
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{
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name: 'm:e',
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elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'v' }] }] }],
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},
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],
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},
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],
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};
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const result = convertOmmlToMathml(omml, doc);
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const mpadded = result!.querySelector('mpadded');
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expect(mpadded).not.toBeNull();
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expect(mpadded!.getAttribute('width')).toBe('0');
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const mphantom = mpadded!.querySelector('mphantom');
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expect(mphantom).toBeNull();
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expect(mpadded!.textContent).toBe('v');
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});
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it('renders visible phantom with zeroed ascent as <mpadded height="0"> without hiding', () => {
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const omml = {
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name: 'm:oMath',
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elements: [
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{
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name: 'm:phant',
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elements: [
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{
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name: 'm:phantPr',
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elements: [{ name: 'm:zeroAsc', attributes: { 'm:val': '1' } }],
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},
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{
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name: 'm:e',
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elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'z' }] }] }],
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},
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],
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},
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],
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};
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const result = convertOmmlToMathml(omml, doc);
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const mpadded = result!.querySelector('mpadded');
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expect(mpadded).not.toBeNull();
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expect(mpadded!.getAttribute('height')).toBe('0');
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expect(mpadded!.querySelector('mphantom')).toBeNull();
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expect(mpadded!.textContent).toBe('z');
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});
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it('renders invisible phantom with m:show="0" and zeroed height as <mpadded> wrapping <mphantom>', () => {
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const omml = {
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name: 'm:oMath',
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elements: [
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{
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name: 'm:phant',
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elements: [
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{
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name: 'm:phantPr',
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elements: [
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{ name: 'm:show', attributes: { 'm:val': '0' } },
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{ name: 'm:zeroAsc', attributes: { 'm:val': '1' } },
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],
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},
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{
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name: 'm:e',
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elements: [{ name: 'm:r', elements: [{ name: 'm:t', elements: [{ type: 'text', text: 'z' }] }] }],
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},
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],
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},
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],
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};
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const result = convertOmmlToMathml(omml, doc);
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const mpadded = result!.querySelector('mpadded');
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expect(mpadded).not.toBeNull();
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expect(mpadded!.getAttribute('height')).toBe('0');
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expect(mpadded!.querySelector('mphantom')).not.toBeNull();
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});
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});

‎packages/layout-engine/painters/dom/src/features/math/omml-to-mathml.ts‎

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@@ -26,6 +26,7 @@ import {
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convertLowerLimit,
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convertUpperLimit,
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convertNary,
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convertPhantom,
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} from './converters/index.js';
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export const MATHML_NS = 'http://www.w3.org/1998/Math/MathML';
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'm:limLow': convertLowerLimit, // Lower limit (e.g., lim)
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'm:limUpp': convertUpperLimit, // Upper limit
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'm:nary': convertNary, // N-ary operator (integral, summation, product)
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'm:phant': convertPhantom, // Phantom (invisible spacing placeholder)
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'm:rad': convertRadical, // Radical (square root, nth root)
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'm:sSub': convertSubscript, // Subscript
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'm:sSup': convertSuperscript, // Superscript
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'm:box': null, // Box (invisible grouping container)
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'm:groupChr': null, // Group character (overbrace, underbrace)
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'm:m': null, // Matrix (grid of elements)
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'm:phant': null, // Phantom (invisible spacing placeholder)
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};
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/** OMML argument/container elements that wrap children in <mrow>. */

‎tests/behavior/tests/importing/fixtures/math-phantom-tests.docx‎

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