Hide .notdef glyphs in non-embedded Type1 fonts and don't ignore Widths

Fixes #11403
The PDF uses the non-embedded Type1 font Helvetica. Character codes 194 and 160 (`Â` and `NBSP`) are encoded as `.notdef`. We shouldn't show those glyphs because it seems that Acrobat Reader doesn't draw glyphs that are named `.notdef` in fonts like this.

In addition to testing `glyphName === ".notdef"`, we must test also `glyphName === ""` because the name `""` is used in `core/encodings.js` for undefined glyphs in encodings like `WinAnsiEncoding`.

The solution above hides the `Â` characters but now the replacement character (space) appears to be too wide. I found out that PDF.js ignores font's `Widths` array if the font has no `FontDescriptor` entry. That happens in #11403, so the default widths of Helvetica were used as specified in `core/metrics.js` and `.nodef` got a width of 333. The correct width is 0 as specified by the `Widths` array in the PDF. Thus we must never ignore `Widths`.

src/core/evaluator.js

@@ -2945,6 +2945,8 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       var type = preEvaluatedFont.type;
       var maxCharIndex = composite ? 0xffff : 0xff;
       var properties;
+      const firstChar = dict.get("FirstChar") || 0;
+      const lastChar = dict.get("LastChar") || maxCharIndex;
 
       if (!descriptor) {
         if (type === "Type3") {
@@ -2981,15 +2983,25 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
             widths: metrics.widths,
             defaultWidth: metrics.defaultWidth,
             flags,
-            firstChar: 0,
-            lastChar: maxCharIndex,
+            firstChar,
+            lastChar,
           };
+          const widths = dict.get("Widths");
           return this.extractDataStructures(dict, dict, properties).then(
             properties => {
+              if (widths) {
+                const glyphWidths = [];
+                let j = firstChar;
+                for (let i = 0, ii = widths.length; i < ii; i++) {
+                  glyphWidths[j++] = this.xref.fetchIfRef(widths[i]);
+                }
+                properties.widths = glyphWidths;
+              } else {
                 properties.widths = this.buildCharCodeToWidth(
                   metrics.widths,
                   properties
                 );
+              }
               return new Font(baseFontName, null, properties);
             }
           );
@@ -3001,8 +3013,6 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
       // to ignore this rule when a variant of a standard font is used.
       // TODO Fill the width array depending on which of the base font this is
       // a variant.
-      var firstChar = dict.get("FirstChar") || 0;
-      var lastChar = dict.get("LastChar") || maxCharIndex;
 
       var fontName = descriptor.get("FontName");
       var baseFont = dict.get("BaseFont");

src/core/fonts.js

@@ -3392,6 +3392,16 @@ var Font = (function FontClosure() {
       // back to the char code.
       fontCharCode = this.toFontChar[charcode] || charcode;
       if (this.missingFile) {
+        const glyphName =
+          this.differences[charcode] || this.defaultEncoding[charcode];
+        if (
+          (glyphName === ".notdef" || glyphName === "") &&
+          this.type === "Type1"
+        ) {
+          // .notdef glyphs should be invisible in non-embedded Type1 fonts, so
+          // replace them with spaces.
+          fontCharCode = 0x20;
+        }
         fontCharCode = mapSpecialUnicodeValues(fontCharCode);
       }
 

test/pdfs/.gitignore

@@ -167,6 +167,7 @@
 !issue3405r.pdf
 !issue7339_reduced.pdf
 !issue3438.pdf
+!issue11403_reduced.pdf
 !issue2074.pdf
 !scan-bad.pdf
 !bug847420.pdf

test/pdfs/issue11403_reduced.pdf

@@ -0,0 +1,90 @@
+%PDF-1.5
+%âãÏÓ
+1 0 obj
+<<
+/Type /Catalog
+/Pages 2 0 R
+>>
+endobj
+
+2 0 obj
+<<
+/Type /Pages
+/Count 1
+/Kids [3 0 R]
+>>
+endobj
+
+3 0 obj
+<<
+/Type /Page
+/Parent 2 0 R
+/Contents 6 0 R
+/MediaBox [0 0 200 50]
+/Resources 4 0 R
+>>
+endobj
+
+4 0 obj
+<<
+  /Font << /F2 5 0 R >>
+>>
+endobj
+
+5 0 obj
+<<
+  /Type /Font
+  /Subtype /Type1
+  /BaseFont /Helvetica
+  /Encoding <<
+    /Type /Encoding
+    /Differences [32 /space 35 /numbersign 37 /percent 40 /parenleft /parenright
+      44 /comma /hyphen /period /slash /zero /one /two /three /four /five /six
+      /seven /eight /nine /colon /semicolon /less 65 /A /B /C /D /E /F /G /H /I
+      /J /K /L /M /N /O /P /Q /R /S /T /U /V /W /X /Y 91 /bracketleft 93 /bracketright
+      97 /a /b /c /d /e /f /g /h /i /j /k /l /m /n /o /p 114 /r /s /t /u /v /w /x
+      /y /z 128 /.notdef 147 /.notdef 160 /.notdef 194 /.notdef 226 /.notdef]
+  >>
+  /FirstChar 32
+  /LastChar 226
+  /Widths [278 0 0 556 0 889 0 0 333 333 0 0 278 333 278 278 556 556 556 556 556
+    556 556 556 556 556 278 278 584 0 0 0 0 667 667 722 722 667 611 778 722 278
+    500 667 556 833 722 778 667 778 722 667 611 722 667 944 667 667 0 278 0 278
+    0 0 0 556 556 500 556 556 278 556 556 222 222 500 222 833 556 556 556 0 333
+    500 278 556 500 722 500 500 500 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+    0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+    0 0 0 0 0 0 0 0 0 0 0  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+    0 0 0 0 0 0]
+>>
+endobj
+
+6 0 obj
+<< /Length 71 >>
+stream
+BT
+  14 17 Td
+  /F2 18 Tf
+  (\302\240 2. Eat a healthy diet.) Tj
+ET
+endstream
+endobj
+
+xref
+0 7
+0000000000 65535 f
+0000000017 00000 n
+0000000074 00000 n
+0000000140 00000 n
+0000000254 00000 n
+0000000306 00000 n
+0000001548 00000 n
+
+trailer
+<<
+/Size 7
+/Root 1 0 R
+/ID [<7b642074abed518fedb35b69fbbf85c0> <7b642074abed518fedb35b69fbbf85c0>]
+>>
+startxref
+1677
+%%EOF

test/test_manifest.json

@@ -1419,6 +1419,12 @@
        "lastPage": 1,
        "type": "eq"
     },
+    {  "id": "issue11403",
+       "file": "pdfs/issue11403_reduced.pdf",
+       "md5": "08287b64f442cb7c329b97c4774aa1cd",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "issue11139",
        "file": "pdfs/issue11139.pdf",
        "md5": "006dd4f4bb1878bc14a12072d81a4524",