From e8ed6c6e245995718da57694dcfc5cbfd9358f74 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Mon, 13 Apr 2026 15:29:02 +0200
Subject: [PATCH] Use a TypedArray in the `createOS2Table` function

---
 src/core/fonts.js | 95 +++++++++++++++++++++++++++--------------------
 1 file changed, 54 insertions(+), 41 deletions(-)

diff --git a/src/core/fonts.js b/src/core/fonts.js
index a4a1d22ad..2f9533966 100644
--- a/src/core/fonts.js
+++ b/src/core/fonts.js
@@ -855,47 +855,60 @@ function createOS2Table(properties, charstrings, override) {
   const winAscent = override.yMax || typoAscent;
   const winDescent = -override.yMin || -typoDescent;
 
-  return (
-    "\x00\x03" + // version
-    "\x02\x24" + // xAvgCharWidth
-    "\x01\xF4" + // usWeightClass
-    "\x00\x05" + // usWidthClass
-    "\x00\x00" + // fstype (0 to let the font loads via font-face on IE)
-    "\x02\x8A" + // ySubscriptXSize
-    "\x02\xBB" + // ySubscriptYSize
-    "\x00\x00" + // ySubscriptXOffset
-    "\x00\x8C" + // ySubscriptYOffset
-    "\x02\x8A" + // ySuperScriptXSize
-    "\x02\xBB" + // ySuperScriptYSize
-    "\x00\x00" + // ySuperScriptXOffset
-    "\x01\xDF" + // ySuperScriptYOffset
-    "\x00\x31" + // yStrikeOutSize
-    "\x01\x02" + // yStrikeOutPosition
-    "\x00\x00" + // sFamilyClass
-    "\x00\x00\x06" +
-    String.fromCharCode(properties.fixedPitch ? 0x09 : 0x00) +
-    "\x00\x00\x00\x00\x00\x00" + // Panose
-    string32(ulUnicodeRange1) + // ulUnicodeRange1 (Bits 0-31)
-    string32(ulUnicodeRange2) + // ulUnicodeRange2 (Bits 32-63)
-    string32(ulUnicodeRange3) + // ulUnicodeRange3 (Bits 64-95)
-    string32(ulUnicodeRange4) + // ulUnicodeRange4 (Bits 96-127)
-    "\x2A\x32\x31\x2A" + // achVendID
-    string16(properties.italicAngle ? 1 : 0) + // fsSelection
-    string16(firstCharIndex || properties.firstChar) + // usFirstCharIndex
-    string16(lastCharIndex || properties.lastChar) + // usLastCharIndex
-    string16(typoAscent) + // sTypoAscender
-    string16(typoDescent) + // sTypoDescender
-    "\x00\x64" + // sTypoLineGap (7%-10% of the unitsPerEM value)
-    string16(winAscent) + // usWinAscent
-    string16(winDescent) + // usWinDescent
-    "\x00\x00\x00\x00" + // ulCodePageRange1 (Bits 0-31)
-    "\x00\x00\x00\x00" + // ulCodePageRange2 (Bits 32-63)
-    string16(properties.xHeight) + // sxHeight
-    string16(properties.capHeight) + // sCapHeight
-    string16(0) + // usDefaultChar
-    string16(firstCharIndex || properties.firstChar) + // usBreakChar
-    "\x00\x03" // usMaxContext
-  );
+  const data = new Uint8Array(96),
+    view = new DataView(data.buffer);
+  let pos = 0;
+
+  pos = setArray(data, pos, [0x00, 0x03]); // version
+  pos = setArray(data, pos, [0x02, 0x24]); // xAvgCharWidth
+  pos = setArray(data, pos, [0x01, 0xf4]); // usWeightClass
+  pos = setArray(data, pos, [0x00, 0x05]); // usWidthClass
+  pos += 2; // fstype (0 to improve browser compatibility), skip redundant "\x00\x00"
+  pos = setArray(data, pos, [0x02, 0x8a]); // ySubscriptXSize
+  pos = setArray(data, pos, [0x02, 0xbb]); // ySubscriptYSize
+  pos += 2; // ySubscriptXOffset, skip redundant "\x00\x00"
+  pos = setArray(data, pos, [0x00, 0x8c]); // ySubscriptYOffset
+  pos = setArray(data, pos, [0x02, 0x8a]); // ySuperScriptXSize
+  pos = setArray(data, pos, [0x02, 0xbb]); // ySuperScriptYSize
+  pos += 2; // ySuperScriptXOffset, skip redundant "\x00\x00"
+  pos = setArray(data, pos, [0x01, 0xdf]); // ySuperScriptYOffset
+  pos = setArray(data, pos, [0x00, 0x31]); // yStrikeOutSize
+  pos = setArray(data, pos, [0x01, 0x02]); // yStrikeOutPosition
+  pos += 2; // sFamilyClass, skip redundant "\x00\x00"
+  pos = setArray(data, pos, [
+    0x00,
+    0x00,
+    0x06,
+    properties.fixedPitch ? 0x09 : 0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+    0x00,
+  ]); // Panose
+  pos = setInt32(view, pos, ulUnicodeRange1); // ulUnicodeRange1 (Bits 0-31)
+  pos = setInt32(view, pos, ulUnicodeRange2); // ulUnicodeRange2 (Bits 32-63)
+  pos = setInt32(view, pos, ulUnicodeRange3); // ulUnicodeRange3 (Bits 64-95)
+  pos = setInt32(view, pos, ulUnicodeRange4); // ulUnicodeRange4 (Bits 96-127)
+  pos = setArray(data, pos, [0x2a, 0x32, 0x31, 0x2a]); // achVendID
+  pos = setInt16(view, pos, properties.italicAngle ? 1 : 0); // fsSelection
+  pos = setInt16(view, pos, firstCharIndex || properties.firstChar); // usFirstCharIndex
+  pos = setInt16(view, pos, lastCharIndex || properties.lastChar); // usLastCharIndex
+  pos = setInt16(view, pos, typoAscent); // sTypoAscender
+  pos = setInt16(view, pos, typoDescent); // sTypoDescender
+  pos = setArray(data, pos, [0x00, 0x64]); // sTypoLineGap (7%-10% of the unitsPerEM value)
+  pos = setInt16(view, pos, winAscent); // usWinAscent
+  pos = setInt16(view, pos, winDescent); // usWinDescent
+  pos += 4; // ulCodePageRange1 (Bits 0-31), skip redundant "\x00\x00\x00\x00"
+  pos += 4; // ulCodePageRange2 (Bits 32-63), skip redundant "\x00\x00\x00\x00"
+  pos = setInt16(view, pos, properties.xHeight); // sxHeight
+  pos = setInt16(view, pos, properties.capHeight); // sCapHeight
+  pos += 2; // usDefaultChar, skip redundant "\x00\x00"
+  pos = setInt16(view, pos, firstCharIndex || properties.firstChar); // usBreakChar
+  setArray(data, pos, [0x00, 0x03]); // usMaxContext
+
+  return data;
 }
 
 function createPostTable(properties) {