Check that Type1C fonts does not actually contain OpenType font files (issue 7598)

This patch is yet another instalment in the (never ending) series of patches for PDF files that specify completely incorrect Type/Subtype for its fonts. In this case Type1/Type1C, when in fact OpenType would have been correct.

Fixes 7598.

src/core/fonts.js

@@ -689,12 +689,17 @@ var Font = (function FontClosure() {
     }
 
     // Some fonts might use wrong font types for Type1C or CIDFontType0C
-    if (subtype === 'Type1C' && (type !== 'Type1' && type !== 'MMType1')) {
-      // Some TrueType fonts by mistake claim Type1C
-      if (isTrueTypeFile(file)) {
-        subtype = 'TrueType';
-      } else {
-        type = 'Type1';
+    if (subtype === 'Type1C') {
+      if (type !== 'Type1' && type !== 'MMType1') {
+        // Some TrueType fonts by mistake claim Type1C
+        if (isTrueTypeFile(file)) {
+          subtype = 'TrueType';
+        } else {
+          type = 'Type1';
+        }
+      } else if (isOpenTypeFile(file)) {
+        // Sometimes the type/subtype can be a complete lie (see issue7598.pdf).
+        type = subtype = 'OpenType';
       }
     }
     if (subtype === 'CIDFontType0C' && type !== 'CIDFontType0') {

test/pdfs/.gitignore

@@ -35,6 +35,7 @@
 !issue7439.pdf
 !issue7446.pdf
 !issue7492.pdf
+!issue7598.pdf
 !filled-background.pdf
 !ArabicCIDTrueType.pdf
 !ThuluthFeatures.pdf

test/test_manifest.json

@@ -1795,6 +1795,13 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue7598",
+       "file": "pdfs/issue7598.pdf",
+       "md5": "c5bc5a779bfcb4b234f853231b56cf60",
+       "rounds": 1,
+       "link": false,
+       "type": "eq"
+    },
     {  "id": "issue7439",
        "file": "pdfs/issue7439.pdf",
        "md5": "56682657990a894c66db26560d3039d7",