Fix the computation of unitsPerEm when the fontMatrix has some negati…

…ve coefficients It's a follow-up of #18253.
mozilla · Jun 24, 2024 · 42bb2b0 · 42bb2b0
1 parent 6784124
commit 42bb2b0
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Showing 4 changed files with 10 additions and 2 deletions.
diff --git a/src/core/fonts.js b/src/core/fonts.js
@@ -799,7 +799,7 @@ function createOS2Table(properties, charstrings, override) {
   const unitsPerEm =
     override.unitsPerEm ||
     (properties.fontMatrix
-      ? 1 / Math.max(...properties.fontMatrix.slice(0, 4))
+      ? 1 / Math.max(...properties.fontMatrix.slice(0, 4).map(Math.abs))
       : 1000);
 
   // if the font units differ to the PDF glyph space units
@@ -3199,7 +3199,7 @@ class Font {
     }
 
     const unitsPerEm = properties.fontMatrix
-      ? 1 / Math.max(...properties.fontMatrix.slice(0, 4))
+      ? 1 / Math.max(...properties.fontMatrix.slice(0, 4).map(Math.abs))
       : 1000;
 
     const builder = new OpenTypeFileBuilder("\x4F\x54\x54\x4F");

diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
@@ -650,3 +650,4 @@
 !issue17998.pdf
 !pdfjs_wikipedia.pdf
 !bug1539074.pdf
+!bug1539074.1.pdf
diff --git a/test/pdfs/bug1539074.1.pdf b/test/pdfs/bug1539074.1.pdf
diff --git a/test/test_manifest.json b/test/test_manifest.json
@@ -10098,6 +10098,13 @@
     "rounds": 1,
     "type": "eq"
   },
+  {
+    "id": "bug1539074_1",
+    "file": "pdfs/bug1539074.1.pdf",
+    "md5": "d15c49142fda433323d3d35f2762cd33",
+    "rounds": 1,
+    "type": "eq"
+  },
   {
     "id": "bug1903731",
     "file": "pdfs/bug1903731.pdf",