Preserve QWord line spacing in DOCX

src/io/wordOffice.ts

@@ -44,8 +44,12 @@ export interface WordParagraphIndent {
 export interface WordParagraphSpacing {
   before?: number;
   after?: number;
+  line?: number;
+  lineRule?: WordParagraphLineRule;
 }
 
+export type WordParagraphLineRule = "auto" | "exact" | "atLeast";
+
 export type WordHeadingLevel = 1 | 2 | 3 | 4 | 5 | 6;
 
 export type WordBlock =
@@ -109,6 +113,7 @@ type DocxModule = {
   AlignmentType?: Record<string, string>;
   Document: new (options: Record<string, unknown>) => unknown;
   HeadingLevel: Record<string, string>;
+  LineRuleType?: Record<string, string>;
   Packer: {
     toBlob?: (document: unknown) => Promise<Blob>;
     toBuffer?: (document: unknown) => Promise<ArrayBuffer | Uint8Array>;
@@ -556,19 +561,27 @@ function docxParagraphSpacing(spacing: WordParagraphSpacing | undefined, default
   const normalized = normalizedParagraphSpacing(spacing);
   return {
     after: normalized.after ?? defaultAfter,
-    ...(normalized.before ? { before: normalized.before } : {})
+    ...(normalized.before ? { before: normalized.before } : {}),
+    ...(normalized.line ? { line: normalized.line, lineRule: normalized.lineRule } : {})
   };
 }
 
 function normalizedParagraphSpacing(spacing: WordParagraphSpacing | undefined) {
   const before = normalizedTwips(spacing?.before);
   const after = normalizedTwips(spacing?.after);
+  const line = normalizedTwips(spacing?.line);
+  const lineRule = normalizedParagraphLineRule(spacing?.lineRule);
   return {
     ...(before ? { before } : {}),
-    ...(after !== undefined ? { after } : {})
+    ...(after !== undefined ? { after } : {}),
+    ...(line ? { line, lineRule } : {})
   };
 }
 
+function normalizedParagraphLineRule(lineRule: WordParagraphLineRule | undefined) {
+  return lineRule === "exact" || lineRule === "atLeast" ? lineRule : "auto";
+}
+
 function normalizedParagraphIndent(indent: WordParagraphIndent | undefined) {
   const left = normalizedTwips(indent?.left);
   const firstLine = normalizedTwips(indent?.firstLine);
@@ -716,9 +729,11 @@ function paragraphSpacingFromElement(element: Element): WordParagraphSpacing | u
   const style = element.getAttribute("style") ?? "";
   const before = cssTwipsValue(style, "margin-top");
   const after = cssTwipsValue(style, "margin-bottom");
+  const lineHeight = cssLineHeightValue(style);
   const spacing = {
     ...(before && before > 0 ? { before } : {}),
-    ...(after && after > 0 ? { after } : {})
+    ...(after && after > 0 ? { after } : {}),
+    ...(lineHeight ? lineHeight : {})
   };
   return Object.keys(spacing).length > 0 ? spacing : undefined;
 }
@@ -736,6 +751,28 @@ function cssTwipsValue(style: string, property: "margin-left" | "margin-top" | "
   return cssLengthToTwips(raw);
 }
 
+function cssLineHeightValue(style: string): WordParagraphSpacing | undefined {
+  const raw = /(?:^|;)\s*line-height\s*:\s*([^;]+)/i.exec(style)?.[1]?.trim().toLowerCase() ?? "";
+  if (!raw || ["inherit", "initial", "unset", "revert", "normal"].includes(raw)) {
+    return undefined;
+  }
+
+  const ratioMatch = /^([0-9]+(?:\.[0-9]+)?)$/.exec(raw);
+  if (ratioMatch) {
+    const ratio = Number.parseFloat(ratioMatch[1]);
+    return Number.isFinite(ratio) && ratio > 0 ? { line: Math.round(ratio * 240), lineRule: "auto" } : undefined;
+  }
+
+  const percentMatch = /^([0-9]+(?:\.[0-9]+)?)%$/.exec(raw);
+  if (percentMatch) {
+    const ratio = Number.parseFloat(percentMatch[1]) / 100;
+    return Number.isFinite(ratio) && ratio > 0 ? { line: Math.round(ratio * 240), lineRule: "auto" } : undefined;
+  }
+
+  const line = cssLengthToTwips(raw);
+  return line && line > 0 ? { line, lineRule: "exact" } : undefined;
+}
+
 function cssLengthToTwips(raw: string) {
   if (!raw || ["inherit", "initial", "unset", "revert", "auto"].includes(raw)) {
     return undefined;
@@ -1148,12 +1185,32 @@ function docxParagraphSpacingStyles(properties: XmlRecord) {
   const spacing = childRecord(properties, "w:spacing");
   const before = docxTwipsAttribute(spacing, ["w:before"]);
   const after = docxTwipsAttribute(spacing, ["w:after"]);
+  const line = docxTwipsAttribute(spacing, ["w:line"]);
+  const lineRule = docxAttribute(spacing, "w:lineRule");
   return [
     before ? `margin-top: ${formatPointSize(before / 20)}pt;` : "",
-    after && after !== defaultParagraphSpacingAfterTwips ? `margin-bottom: ${formatPointSize(after / 20)}pt;` : ""
+    after && after !== defaultParagraphSpacingAfterTwips ? `margin-bottom: ${formatPointSize(after / 20)}pt;` : "",
+    docxLineHeightStyle(line, lineRule)
   ].filter(Boolean);
 }
 
+function docxLineHeightStyle(line: number | undefined, lineRule: string) {
+  if (!line || line <= 0) {
+    return "";
+  }
+
+  const normalizedRule = lineRule.trim().toLowerCase();
+  if (!normalizedRule || normalizedRule === "auto") {
+    return `line-height: ${formatLineHeightRatio(line / 240)};`;
+  }
+
+  return `line-height: ${formatPointSize(line / 20)}pt;`;
+}
+
+function formatLineHeightRatio(value: number) {
+  return Number.isInteger(value) ? String(value) : value.toFixed(2).replace(/0+$/, "").replace(/\.$/, "");
+}
+
 function docxParagraphListInfo(properties: XmlRecord, numberingDefinitions: DocxNumberingDefinitions): DocxListInfo | undefined {
   const numbering = childRecord(properties, "w:numPr");
   const numId = docxAttribute(childRecord(numbering, "w:numId"), "w:val");