Font ascent descent calculation fix

src/core/cff_parser.js

@@ -257,8 +257,8 @@ var CFFParser = (function CFFParserClosure() {
       var fontBBox = topDict.getByName('FontBBox');
       if (fontBBox) {
         // adjusting ascent/descent
-        properties.ascent = fontBBox[3];
+        properties.ascent = Math.max(fontBBox[3], fontBBox[1]);
-        properties.descent = fontBBox[1];
+        properties.descent = Math.min(fontBBox[1], fontBBox[3]);
         properties.ascentScaled = true;
       }
 

src/core/type1_parser.js

@@ -705,8 +705,8 @@ var Type1Parser = (function Type1ParserClosure() {
           case 'FontBBox':
             var fontBBox = this.readNumberArray();
             // adjusting ascent/descent
-            properties.ascent = fontBBox[3];
+            properties.ascent = Math.max(fontBBox[3], fontBBox[1]);
-            properties.descent = fontBBox[1];
+            properties.descent = Math.min(fontBBox[1], fontBBox[3]);
             properties.ascentScaled = true;
             break;
         }

test/pdfs/.gitignore

@@ -271,3 +271,4 @@
 !zero_descent.pdf
 !operator-in-TJ-array.pdf
 !issue7878.pdf
+!font_ascent_descent.pdf

test/test_manifest.json

@@ -3367,5 +3367,11 @@
        "link": false,
        "rounds": 1,
        "type": "text"
+    },
+    {  "id": "font_ascent_descent",
+       "file": "pdfs/font_ascent_descent.pdf",
+       "md5": "c0048a7735010002b998c112335e47bf",
+       "rounds": 1,
+       "type": "eq"
     }
 ]