Improve handling of mismatching /BaseFont and /FontName entries for non-embedded fonts (issue 7454)

This patch is the result of me going through some old issues regarding non-embedded Wingdings support.

There's a few different things wrong in the referenced PDF document:
 - The /BaseFont and /FontName entries don't agree on the name of the fonts, with one font using `/BaseFont /Wingdings-Regular` and `/FontName /wg09np` which obviously makes no sense.
   To address this we'll compare the font-names against our lists of known ones and ignore /FontName entries that don't make sense iff the /BaseFont entry is a known font-name.
 - The non-embedded Wingdings font also set an incorrect /Encoding, in this case /MacRomanEncoding, which should have been fixed by PR 16465. However this doesn't work since the font has *bogus* font-flags, that fail to categorize the font as Symbolic.
   To address this we'll also compare the font-name against the list of known symbol fonts.

src/core/evaluator.js

@@ -49,6 +49,7 @@ import {
   getStandardFontName,
   getStdFontMap,
   getSymbolsFonts,
+  isKnownFontName,
 } from "./standard_fonts.js";
 import { getTilingPatternIR, Pattern } from "./pattern.js";
 import { getXfaFontDict, getXfaFontName } from "./xfa_fonts.js";
@@ -3487,14 +3488,11 @@ class PartialEvaluator {
       }
     }
 
-    const nonEmbeddedFont = !properties.file || properties.isInternalFont;
+    const nonEmbeddedFont = !properties.file || properties.isInternalFont,
+      isSymbolsFontName = getSymbolsFonts()[properties.name];
     // Ignore an incorrectly specified named encoding for non-embedded
     // symbol fonts (fixes issue16464.pdf).
-    if (
-      baseEncodingName &&
-      nonEmbeddedFont &&
-      getSymbolsFonts()[properties.name]
-    ) {
+    if (baseEncodingName && nonEmbeddedFont && isSymbolsFontName) {
       baseEncodingName = null;
     }
 
@@ -3512,7 +3510,7 @@ class PartialEvaluator {
       }
       // The Symbolic attribute can be misused for regular fonts
       // Heuristic: we have to check if the font is a standard one also
-      if (isSymbolicFont) {
+      if (isSymbolicFont || isSymbolsFontName) {
         encoding = MacRomanEncoding;
         if (nonEmbeddedFont) {
           if (/Symbol/i.test(properties.name)) {
@@ -4249,19 +4247,25 @@ class PartialEvaluator {
       baseFont = Name.get(baseFont);
     }
 
-    if (!isType3Font) {
     const fontNameStr = fontName?.name;
     const baseFontStr = baseFont?.name;
-      if (fontNameStr !== baseFontStr) {
+    if (!isType3Font && fontNameStr !== baseFontStr) {
       info(
         `The FontDescriptor's FontName is "${fontNameStr}" but ` +
           `should be the same as the Font's BaseFont "${baseFontStr}".`
       );
-        // Workaround for cases where e.g. fontNameStr = 'Arial' and
+      // - Workaround for cases where e.g. fontNameStr = 'Arial' and
       //   baseFontStr = 'Arial,Bold' (needed when no font file is embedded).
-        if (fontNameStr && baseFontStr?.startsWith(fontNameStr)) {
-          fontName = baseFont;
-        }
+      //
+      // - Workaround for cases where e.g. fontNameStr = 'wg09np' and
+      //   baseFontStr = 'Wingdings-Regular' (fixes issue7454.pdf).
+      if (
+        fontNameStr &&
+        baseFontStr &&
+        (baseFontStr.startsWith(fontNameStr) ||
+          (!isKnownFontName(fontNameStr) && isKnownFontName(baseFontStr)))
+      ) {
+        fontName = null;
       }
     }
     fontName ||= baseFont;

src/core/standard_fonts.js

@@ -309,6 +309,9 @@ const getSymbolsFonts = getLookupTableFactory(function (t) {
   t.Dingbats = true;
   t.Symbol = true;
   t.ZapfDingbats = true;
+  t.Wingdings = true;
+  t["Wingdings-Bold"] = true;
+  t["Wingdings-Regular"] = true;
 });
 
 // Glyph map for well-known standard fonts. Sometimes Ghostscript uses CID
@@ -888,6 +891,16 @@ function getStandardFontName(name) {
   return stdFontMap[fontName];
 }
 
+function isKnownFontName(name) {
+  const fontName = normalizeFontName(name);
+  return !!(
+    getStdFontMap()[fontName] ||
+    getNonStdFontMap()[fontName] ||
+    getSerifFonts()[fontName] ||
+    getSymbolsFonts()[fontName]
+  );
+}
+
 export {
   getFontNameToFileMap,
   getGlyphMapForStandardFonts,
@@ -898,4 +911,5 @@ export {
   getSupplementalGlyphMapForArialBlack,
   getSupplementalGlyphMapForCalibri,
   getSymbolsFonts,
+  isKnownFontName,
 };

test/pdfs/.gitignore

@@ -490,6 +490,7 @@
 !issue11656.pdf
 !annotation-fileattachment.pdf
 !annotation-text-widget.pdf
+!issue7454.pdf
 !issue15443.pdf
 !annotation-choice-widget.pdf
 !issue10900.pdf

test/test_manifest.json

@@ -5042,6 +5042,12 @@
       "link": true,
       "type": "load"
     },
+    {  "id": "issue7454",
+       "file": "pdfs/issue7454.pdf",
+       "md5": "45889bf6a9d3e2eccd01dc48668b21e5",
+       "rounds": 1,
+       "type": "eq"
+    },
     { "id": "bigboundingbox",
       "file": "pdfs/bigboundingbox.pdf",
       "md5": "e5c5e2cb80826d6ebf535413865270cd",