Use widths defined by font for standard fonts.

There doesn't seem to be anything definitive about this in
the spec, but from experimenting, it seems acrobat lets
PDFs override the widths of the standard fonts.

src/core/fonts.js

@@ -1319,11 +1319,12 @@ var Font = (function FontClosure() {
       let fontName = name.replace(/[,_]/g, "-").replace(/\s/g, "");
       var stdFontMap = getStdFontMap(),
         nonStdFontMap = getNonStdFontMap();
-      var isStandardFont =
-        !!stdFontMap[fontName] ||
-        !!(nonStdFontMap[fontName] && stdFontMap[nonStdFontMap[fontName]]);
-      fontName = stdFontMap[fontName] || nonStdFontMap[fontName] || fontName;
+      const isStandardFont = !!stdFontMap[fontName];
+      const isMappedToStandardFont = !!(
+        nonStdFontMap[fontName] && stdFontMap[nonStdFontMap[fontName]]
+      );
 
+      fontName = stdFontMap[fontName] || nonStdFontMap[fontName] || fontName;
       this.bold = fontName.search(/bold/gi) !== -1;
       this.italic =
         fontName.search(/oblique/gi) !== -1 ||
@@ -1334,9 +1335,9 @@ var Font = (function FontClosure() {
       this.black = name.search(/Black/g) !== -1;
 
       // if at least one width is present, remeasure all chars when exists
-      this.remeasure = Object.keys(this.widths).length > 0;
+      this.remeasure = !isStandardFont && Object.keys(this.widths).length > 0;
       if (
-        isStandardFont &&
+        (isStandardFont || isMappedToStandardFont) &&
         type === "CIDFontType2" &&
         this.cidEncoding.startsWith("Identity-")
       ) {

test/pdfs/.gitignore

@@ -357,6 +357,7 @@
 !issue6298.pdf
 !issue6889.pdf
 !bug1001080.pdf
+!bug1671312_reduced.pdf
 !issue6108.pdf
 !issue6113.pdf
 !openoffice.pdf

test/test_manifest.json

@@ -2259,6 +2259,12 @@
        "link": false,
        "type": "text"
     },
+    {  "id": "bug1671312_reduced",
+       "file": "pdfs/bug1671312_reduced.pdf",
+       "md5": "db13fe3f03a7d0bd0e248f5c2bcb2a5d",
+       "rounds": 1,
+       "type": "eq"
+    },
     {  "id": "issue7020",
        "file": "pdfs/issue7020.pdf",
        "md5": "93b464e21c649e64ae92eeafe99fc31b",