Allow /XYZ destinations without zoom parameter (issue 18408)

According to the PDF specification these destinations should have a zoom parameter, which may however be `null`, but it shouldn't be omitted; please see https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf#G11.2095870

Hence we try to work-around bad PDF generators by making the zoom parameter optional when validating explicit destinations in both the worker and the viewer.

src/core/catalog.js

@@ -64,26 +64,27 @@ function isValidExplicitDest(dest) {
   if (!(zoom instanceof Name)) {
     return false;
   }
+  const argsLen = args.length;
   let allowNull = true;
   switch (zoom.name) {
     case "XYZ":
-      if (args.length !== 3) {
+      if (argsLen < 2 || argsLen > 3) {
         return false;
       }
       break;
     case "Fit":
     case "FitB":
-      return args.length === 0;
+      return argsLen === 0;
     case "FitH":
     case "FitBH":
     case "FitV":
     case "FitBV":
-      if (args.length > 1) {
+      if (argsLen > 1) {
         return false;
       }
       break;
     case "FitR":
-      if (args.length !== 4) {
+      if (argsLen !== 4) {
         return false;
       }
       allowNull = false;

test/pdfs/.gitignore

@@ -13,6 +13,7 @@
 !issue1155r.pdf
 !issue2017r.pdf
 !bug1727053.pdf
+!issue18408_reduced.pdf
 !bug1907000_reduced.pdf
 !issue11913.pdf
 !issue2391-1.pdf

test/unit/api_spec.js

@@ -1901,6 +1901,49 @@ describe("api", function () {
       await loadingTask.destroy();
     });
 
+    it("gets outline, with /XYZ destinations that lack zoom parameter (issue 18408)", async function () {
+      const loadingTask = getDocument(
+        buildGetDocumentParams("issue18408_reduced.pdf")
+      );
+      const pdfDoc = await loadingTask.promise;
+      const outline = await pdfDoc.getOutline();
+
+      expect(outline).toEqual([
+        {
+          action: null,
+          attachment: undefined,
+          dest: [{ num: 14, gen: 0 }, { name: "XYZ" }, 65, 705],
+          url: null,
+          unsafeUrl: undefined,
+          newWindow: undefined,
+          setOCGState: undefined,
+          title: "Page 1",
+          color: new Uint8ClampedArray([0, 0, 0]),
+          count: undefined,
+          bold: false,
+          italic: false,
+          items: [],
+        },
+        {
+          action: null,
+          attachment: undefined,
+          dest: [{ num: 13, gen: 0 }, { name: "XYZ" }, 60, 710],
+          url: null,
+          unsafeUrl: undefined,
+          newWindow: undefined,
+          setOCGState: undefined,
+          title: "Page 2",
+          color: new Uint8ClampedArray([0, 0, 0]),
+          count: undefined,
+          bold: false,
+          italic: false,
+          items: [],
+        },
+      ]);
+
+      await loadingTask.destroy();
+    });
+
     it("gets outline, with /FitH destinations that lack coordinate parameter (bug 1907000)", async function () {
       const loadingTask = getDocument(
         buildGetDocumentParams("bug1907000_reduced.pdf")

web/pdf_link_service.js

@@ -505,26 +505,27 @@ class PDFLinkService {
     if (!(typeof zoom === "object" && typeof zoom?.name === "string")) {
       return false;
     }
+    const argsLen = args.length;
     let allowNull = true;
     switch (zoom.name) {
       case "XYZ":
-        if (args.length !== 3) {
+        if (argsLen < 2 || argsLen > 3) {
           return false;
         }
         break;
       case "Fit":
       case "FitB":
-        return args.length === 0;
+        return argsLen === 0;
       case "FitH":
       case "FitBH":
       case "FitV":
       case "FitBV":
-        if (args.length > 1) {
+        if (argsLen > 1) {
           return false;
         }
         break;
       case "FitR":
-        if (args.length !== 4) {
+        if (argsLen !== 4) {
           return false;
         }
         allowNull = false;