Improve TrueType specificiation compliance for generated fonts

src/FontLib/Table/DirectoryEntry.php

@@ -49,20 +49,8 @@ static function computeChecksum($data) {
       $data = str_pad($data, $len + (4 - $mod), "\0");
     }
 
-    $len = mb_strlen($data, '8bit');
-
-    $hi = 0x0000;
-    $lo = 0x0000;
-
-    for ($i = 0; $i < $len; $i += 4) {
-      $hi += (ord($data[$i]) << 8) + ord($data[$i + 1]);
-      $lo += (ord($data[$i + 2]) << 8) + ord($data[$i + 3]);
-      $hi += $lo >> 16;
-      $lo = $lo & 0xFFFF;
-      $hi = $hi & 0xFFFF;
-    }
-
-    return ($hi << 8) + $lo;
+    $table = unpack("N*", $data);
+    return array_sum($table);
   }
 
   function __construct(File $font) {
@@ -93,6 +81,14 @@ function encode($entry_offset) {
     $this->offset = $table_offset;
     $table_length = $data->encode();
 
+    $font->seek($table_offset + $table_length);
+    $pad = 0;
+    $mod = $table_length % 4;
+    if ($mod != 0) {
+      $pad = 4 - $mod;
+      $font->write(str_pad("", $pad, "\0"), $pad);
+    }
+
     $font->seek($table_offset);
     $table_data = $font->read($table_length);
 
@@ -105,7 +101,7 @@ function encode($entry_offset) {
 
     Font::d("Bytes written = $table_length");
 
-    $font->seek($table_offset + $table_length);
+    $font->seek($table_offset + $table_length + $pad);
   }
 
   /**

src/FontLib/Table/Type/cmap.php

@@ -26,6 +26,18 @@ class cmap extends Table {
     "offset"             => self::uint32,
   );
 
+  private static $subtable_v2_format = array(
+    "length"        => self::uint16,
+    "language"      => self::uint16
+  );
+
+  private static $subtable_v2_format_subheader = array(
+    "firstCode"     => self::uint16,
+    "entryCount"    => self::uint16,
+    "idDelta"       => self::int16,
+    "idRangeOffset" => self::uint16
+  );
+
   private static $subtable_v4_format = array(
     "length"        => self::uint16,
     "language"      => self::uint16,
@@ -38,7 +50,7 @@ class cmap extends Table {
   private static $subtable_v12_format = array(
     "length"        => self::uint32,
     "language"      => self::uint32,
-    "ngroups"    => self::uint32
+    "ngroups"       => self::uint32
   );
 
   protected function _parse() {
@@ -60,105 +72,170 @@ protected function _parse() {
 
       $subtable["format"] = $font->readUInt16();
 
-      // @todo Only CMAP version 4 and 12
-      if (($subtable["format"] != 4) && ($subtable["format"] != 12)) {
-        unset($data["subtables"][$i]);
-        $data["numberSubtables"]--;
-        continue;
-      }
-
-      if ($subtable["format"] == 12) {
-
-        $font->readUInt16();
-
-        $subtable += $font->unpack(self::$subtable_v12_format);
-
-        $glyphIndexArray = array();
-        $endCodes = array();
-        $startCodes = array();
-
-        for ($p = 0; $p < $subtable['ngroups']; $p++) {
-
-          $startCode = $startCodes[] = $font->readUInt32();
-          $endCode = $endCodes[] = $font->readUInt32();
-          $startGlyphCode = $font->readUInt32();
-
-          for ($c = $startCode; $c <= $endCode; $c++) {
-            $glyphIndexArray[$c] = $startGlyphCode;
-            $startGlyphCode++;
-          }
-        }
-
-        $subtable += array(
-          "startCode" => $startCodes,
-          "endCode" => $endCodes,
-          "glyphIndexArray" => $glyphIndexArray,
-        );
-
-      }
-      else if ($subtable["format"] == 4) {
-
-        $subtable += $font->unpack(self::$subtable_v4_format);
-
-        $segCount             = $subtable["segCountX2"] / 2;
-        $subtable["segCount"] = $segCount;
-
-        $endCode = $font->readUInt16Many($segCount);
-
-        $font->readUInt16(); // reservedPad
-
-        $startCode = $font->readUInt16Many($segCount);
-        $idDelta   = $font->readInt16Many($segCount);
-
-        $ro_start      = $font->pos();
-        $idRangeOffset = $font->readUInt16Many($segCount);
-
-        $glyphIndexArray = array();
-        for ($i = 0; $i < $segCount; $i++) {
-          $c1 = $startCode[$i];
-          $c2 = $endCode[$i];
-          $d  = $idDelta[$i];
-          $ro = $idRangeOffset[$i];
-
-          if ($ro > 0) {
-            $font->seek($subtable["offset"] + 2 * $i + $ro);
+      switch ($subtable["format"]) {
+        case 0:
+        case 6:
+        case 8:
+        case 10:
+        case 13:
+        case 14:
+          unset($data["subtables"][$i]);
+          $data["numberSubtables"]--;
+          continue 2;
+
+        case 2:
+          $subtable += $font->unpack(self::$subtable_v2_format);
+
+          $subHeaderKeys = array_map(function($val) { return $val / 8; }, $font->readUInt16Many(256));
+          $subHeaders = array();
+
+          $glyphIdArray = array();
+          $maxSubHeaderIndex = max($subHeaderKeys);
+          for ($i = 0; $i <= $maxSubHeaderIndex; $i++) {
+            $subHeader = $font->unpack(self::$subtable_v2_format_subheader);
+            $offset = $font->pos();
+            $subHeader["glyphIdArrayOffset"] = $offset + $subHeader["idRangeOffset"] - 2;
+            $subHeaders[$i] = $subHeader;
+
+            if (!\array_key_exists($subHeader["glyphIdArrayOffset"], $glyphIdArray) || count($glyphIdArray[$subHeader["glyphIdArrayOffset"]]) < $subHeader["entryCount"]) {
+              $font->seek($subHeader["glyphIdArrayOffset"]);
+              $glyphIdArray[$subHeader["glyphIdArrayOffset"]] = $font->readUInt16Many($subHeader["entryCount"]);
+              $font->seek($offset);
+            }
           }
 
-          for ($c = $c1; $c <= $c2; $c++) {
-            if ($c === 0xFFFF) {
-              continue;
+          $glyphIndexArray = array();
+          foreach ($subHeaderKeys as $highByte => $subHeaderKey) {
+            $subHeader = $subHeaders[$subHeaderKey];
+            if ($subHeaderKey === 0) {
+              $c = $highByte;
+              if ($c < $subHeader["firstCode"] || $c >= ($subHeader["firstCode"] + $subHeader["entryCount"])) {
+                $glyphIndexArray[$c] = 0;
+                continue;
+              }
+              $c = $highByte;
+              $index = $c - $subHeader["firstCode"];
+              $glyphId = $glyphIdArray[$subHeader["glyphIdArrayOffset"]][$index];
+              if ($glyphId === 0) {
+                $glyphIndexArray[$c] = 0;
+              } else {
+                $glyphIndexArray[$c] = ($glyphId + $subHeader["idDelta"]) & 0xFFFF;
+              }
+            } else {
+              for ($index = 0; $index < $subHeader["entryCount"]; $index++) {
+                $c = null;
+                    $lowByte = $subHeader["firstCode"] + $index;
+                $c = (($highByte & 0xFF) << 8) | ($lowByte & 0xFF);
+                $glyphId = $glyphIdArray[$subHeader["glyphIdArrayOffset"]][$index];
+                if ($glyphId === 0) {
+                  $glyphIndexArray[$c] = 0;
+                } else {
+                  $glyphIndexArray[$c] = ($glyphId + $subHeader["idDelta"]) & 0xFFFF;
+                }
+              }
             }
+          }
 
-            if ($ro == 0) {
-              $gid = ($c + $d) & 0xFFFF;
+          $subtable += array(
+            "subHeaderKeys" => $subHeaderKeys,
+            "subHeaders" => $subHeaders,
+            "glyphIdArray" => $glyphIdArray,
+            "glyphIndexArray" => $glyphIndexArray
+          );
+
+          break;
+
+        case 4:
+          $subtable += $font->unpack(self::$subtable_v4_format);
+
+          $segCount             = $subtable["segCountX2"] / 2;
+          $subtable["segCount"] = $segCount;
+
+          $endCode = $font->readUInt16Many($segCount);
+
+          $font->readUInt16(); // reservedPad
+
+          $startCode = $font->readUInt16Many($segCount);
+          $idDelta   = $font->readInt16Many($segCount);
+
+          $ro_start      = $font->pos();
+          $idRangeOffset = $font->readUInt16Many($segCount);
+
+          $glyphIndexArray = array();
+          for ($i = 0; $i < $segCount; $i++) {
+            $c1 = $startCode[$i];
+            $c2 = $endCode[$i];
+            $d  = $idDelta[$i];
+            $ro = $idRangeOffset[$i];
+
+            if ($ro > 0) {
+              $font->seek($subtable["offset"] + 2 * $i + $ro);
             }
-            else {
-              $offset = ($c - $c1) * 2 + $ro;
-              $offset = $ro_start + 2 * $i + $offset;
-
-              $gid = 0;
-              if ($font->seek($offset) === true) {
-                $gid = $font->readUInt16();
+
+            for ($c = $c1; $c <= $c2; $c++) {
+              if ($c === 0xFFFF) {
+                continue;
               }
-
-              if ($gid != 0) {
-                $gid = ($gid + $d) & 0xFFFF;
+
+              if ($ro == 0) {
+                $gid = ($c + $d) & 0xFFFF;
+              }
+              else {
+                $offset = ($c - $c1) * 2 + $ro;
+                $offset = $ro_start + 2 * $i + $offset;
+
+                $gid = 0;
+                if ($font->seek($offset) === true) {
+                  $gid = $font->readUInt16();
+                }
+
+                if ($gid != 0) {
+                  $gid = ($gid + $d) & 0xFFFF;
+                }
+              }
+
+              if ($gid >= 0) {
+                $glyphIndexArray[$c] = $gid;
               }
             }
-
-            if ($gid >= 0) {
-              $glyphIndexArray[$c] = $gid;
+          }
+
+          $subtable += array(
+            "endCode"         => $endCode,
+            "startCode"       => $startCode,
+            "idDelta"         => $idDelta,
+            "idRangeOffset"   => $idRangeOffset,
+            "glyphIndexArray" => $glyphIndexArray
+          );
+          break;
+
+        case 12:
+          $font->readUInt16();
+
+          $subtable += $font->unpack(self::$subtable_v12_format);
+
+          $glyphIndexArray = array();
+          $endCodes = array();
+          $startCodes = array();
+
+          for ($p = 0; $p < $subtable['ngroups']; $p++) {
+
+            $startCode = $startCodes[] = $font->readUInt32();
+            $endCode = $endCodes[] = $font->readUInt32();
+            $startGlyphCode = $font->readUInt32();
+
+            for ($c = $startCode; $c <= $endCode; $c++) {
+              $glyphIndexArray[$c] = $startGlyphCode;
+              $startGlyphCode++;
             }
           }
-        }
-
-        $subtable += array(
-          "endCode"         => $endCode,
-          "startCode"       => $startCode,
-          "idDelta"         => $idDelta,
-          "idRangeOffset"   => $idRangeOffset,
-          "glyphIndexArray" => $glyphIndexArray,
-        );
+
+          $subtable += array(
+            "startCode" => $startCodes,
+            "endCode" => $endCodes,
+            "glyphIndexArray" => $glyphIndexArray,
+          );
+          break;
       }
     }
 
@@ -202,7 +279,7 @@ function _encode() {
       $prevGid  = $gid;
     }
 
-    $segments[][] = array(0xFFFF, 0xFFFF);
+    $segments[][] = array(0xFFFF, null);
 
     $startCode = array();
     $endCode   = array();

src/FontLib/Table/Type/glyf.php

@@ -143,7 +143,16 @@ protected function _encode() {
     $length = 0;
     foreach ($subset as $gid) {
       $loca[] = $length;
-      $length += $data[$gid]->encode();
+
+      $bytes = $data[$gid]->encode();
+
+      $pad = 0;
+      $mod = $bytes % 4;
+      if ($mod != 0) {
+        $pad = 4 - $mod;
+        $font->write(str_pad("", $pad, "\0"), $pad);
+      }
+      $length += $bytes + $pad;
     }
 
     $loca[]                             = $length; // dummy loca

src/FontLib/Table/Type/head.php

@@ -43,4 +43,9 @@ protected function _parse() {
       throw new Exception("Incorrect magic number (" . dechex($this->data["magicNumber"]) . ")");
     }
   }
+
+  function _encode() {
+    $this->data["checkSumAdjustment"] = 0;
+    return parent::_encode();
+  }
 }