Question

我在构建OpenType字体时遇到了围绕这3个规范属性的错误：

searchRange
rangeShift
entrySelector

在this页上，它是这样说的：

searchRange 是小于或等于表中项目数的2的最大幂，即可以轻松搜索的最大项目数。

rangeShift 是项目数减去searchRange；也就是说，如果仅查看searchRange项目，则无法查看的项目数。

entrySelector 是log2（searchRange）。

鉴于这些信息，我们有：

searchRange = maxPowerOf2 <= n，其中n是表中的项目数。
rangeShift = n - searchRange
entrySelector = log2(searchRange)

但是我们再读一点。

请注意，searchRange，entrySelector和rangeShift都乘以16，代表目录条目的大小。

现在我们有了：

searchRange = 16 * maxPowerOf2 <= n，其中n是表中的项目数。
rangeShift = 16 * n - searchRange
entrySelector = 16 * log2(searchRange)

但是等等，下表显示了这一点：

searchRange ：(maximum power of 2 <= numTables)*16

entrySelector ：log2(maximum power of 2 <= numTables)

rangeShift ：numTables*16-searchRange

所以这意味着我们的entrySelector似乎没有16乘数：

searchRange = 16 * maxPowerOf2 <= n，其中n是表中的项目数。
rangeShift = 16 * n - searchRange
entrySelector = log2(searchRange)

但是等等，there's more：

searchRange (Maximum power of 2 <= numTables) x 16

entrySelector Log2(maximum power of 2 <= numTables)

rangeShift NumTables x 16-searchRange

与我们的最后一个匹配。

检查任意font source code，它也匹配最后一个。

我不明白的是，唯一对我有用的是第一个：

let maxPowerOf2 = Math.pow(2, maxExponentFor2);
var searchRange = maxPowerOf2
var entrySelector = Math.log2(searchRange)
var rangeShift = numTables - searchRange

这是唯一让我克服错误的人：

OTS parsing error: incorrect entrySelector for table directory

但是我最终遇到此错误：

OTS parsing error: CFF : misaligned table

给出以下输出：

4f54 544f 0009 0008 0003 0001 4346 4620
0000 0000 0000 00c2 9c00 0000 0563 6d61
7000 0000 0000 0000 c2a4 0000 0024 6865
6164 0000 0000 0000 00c3 8800 0000 3668
6865 6100 0000 0000 0001 0000 0000 2468
6d74 7800 0000 0000 0001 2400 0000 006d
6178 7000 0000 0000 0001 2400 0000 066e
616d 6500 0000 0000 0001 2c00 0000 064f
532f 3200 0000 0000 0001 3400 0000 6470
6f73 7400 0000 0000 0001 c298 0000 0020
0200 0400 0000 0000 0000 0001 0000 0006
0000 0010 0004 0010 0000 0002 0002 0000
0000 c3bf c3bf 0000 c3bf c3bf 0001 0000
0001 0000 0001 0000 0000 0000 5f0f 3cc3
b500 0303 c3a8 0000 0000 c398 6526 c388
0000 0000 c398 6526 c388 0000 0000 0000
0000 0000 0003 0002 0000 0000 0000 0001
0000 00c3 8800 6400 0000 0000 0000 0000
0000 0100 0000 0000 0000 0000 0000 0000
0000 0000 0050 0000 0000 0000 0000 0000
0600 0000 0500 0000 0000 0000 0002 c28a
02c2 bb00 0000 c28c 02c2 8a02 c2bb 0000
01c3 9f00 3101 0200 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0058 5858 5800 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0300
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 00

尝试多数操作的方式（两个doc参考和源代码），但这给了我第一个错误，是这样的：

4f54 544f 0009 00c2 8000 0700 1043 4646
2000 0000 0000 0000 c29c 0000 0005 636d
6170 0000 0000 0000 00c2 a400 0000 2468
6561 6400 0000 0000 0000 c388 0000 0036
6868 6561 0000 0000 0000 0100 0000 0024
686d 7478 0000 0000 0000 0124 0000 0000
6d61 7870 0000 0000 0000 0124 0000 0006
6e61 6d65 0000 0000 0000 012c 0000 0006
4f53 2f32 0000 0000 0000 0134 0000 0064
706f 7374 0000 0000 0000 01c2 9800 0000
2002 0004 0000 0000 0000 0000 0100 0000
0600 0000 1000 0400 1000 0000 0200 0200
0000 00c3 bfc3 bf00 00c3 bfc3 bf00 0100
0000 0100 0000 0100 0000 0000 005f 0f3c
c3b5 0003 03c3 a800 0000 00c3 9865 271d
0000 0000 c398 6527 1d00 0000 0000 0000
0000 0000 0300 0200 0000 0000 0000 0100
0000 c388 0064 0000 0000 0000 0000 0000
0001 0000 0000 0000 0000 0000 0000 0000
0000 0000 5000 0000 0000 0000 0000 0006
0000 0005 0000 0000 0000 0000 02c2 8a02
c2bb 0000 00c2 8c02 c28a 02c2 bb00 0001
c39f 0031 0102 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 5858 5858 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000 0003 0000
0000 0000 0000 0000 0000 0000 0000 0000
0000 0000 0000 0000 0000 0000

目前还没有字形，只有最低限度的字形。想知道我缺少什么才能使它正常工作。

如果这完全有用，那就是生成二进制文件的基本数据：

{
  "name": "sfnt",
  "fields": {
    "scalar": {
      "type": "TAG",
      "value": "OTTO"
    },
    "numTables": {
      "type": "USHORT",
      "value": 9
    },
    "searchRange": {
      "type": "USHORT",
      "value": 128
    },
    "entrySelector": {
      "type": "USHORT",
      "value": 7
    },
    "rangeShift": {
      "type": "USHORT",
      "value": 16
    },
    "CFF  Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "CFF "
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 156
          },
          "length": {
            "type": "ULONG",
            "value": 5
          }
        }
      }
    },
    "cmap Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "cmap"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 164
          },
          "length": {
            "type": "ULONG",
            "value": 36
          }
        }
      }
    },
    "head Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "head"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 200
          },
          "length": {
            "type": "ULONG",
            "value": 54
          }
        }
      }
    },
    "hhea Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "hhea"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 256
          },
          "length": {
            "type": "ULONG",
            "value": 36
          }
        }
      }
    },
    "hmtx Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "hmtx"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 292
          },
          "length": {
            "type": "ULONG",
            "value": 0
          }
        }
      }
    },
    "maxp Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "maxp"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 292
          },
          "length": {
            "type": "ULONG",
            "value": 6
          }
        }
      }
    },
    "name Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "name"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 300
          },
          "length": {
            "type": "ULONG",
            "value": 6
          }
        }
      }
    },
    "OS/2 Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "OS/2"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 308
          },
          "length": {
            "type": "ULONG",
            "value": 100
          }
        }
      }
    },
    "post Table Record": {
      "type": "RECORD",
      "value": {
        "name": "Table Record",
        "fields": {
          "tag": {
            "type": "TAG",
            "value": "post"
          },
          "checkSum": {
            "type": "ULONG",
            "value": 0
          },
          "offset": {
            "type": "ULONG",
            "value": 408
          },
          "length": {
            "type": "ULONG",
            "value": 32
          }
        }
      }
    },
    "CFF  table": {
      "type": "RECORD",
      "value": {
        "name": "CFF ",
        "fields": {
          "header": {
            "type": "RECORD",
            "value": {
              "name": "Header",
              "fields": {
                "major": {
                  "type": "BYTE",
                  "value": 2
                },
                "minor": {
                  "type": "BYTE",
                  "value": 0
                },
                "hdrSize": {
                  "type": "BYTE",
                  "value": 4
                },
                "topDictLength": {
                  "type": "USHORT",
                  "value": 0
                }
              }
            }
          }
        }
      }
    },
    "padding_0": {
      "type": "BYTE",
      "value": 0
    },
    "padding_1": {
      "type": "BYTE",
      "value": 0
    },
    "padding_2": {
      "type": "BYTE",
      "value": 0
    },
    "cmap table": {
      "type": "RECORD",
      "value": {
        "name": "cmap",
        "fields": {
          "version": {
            "type": "USHORT",
            "value": 0
          },
          "numTables": {
            "type": "USHORT",
            "value": 1
          },
          "platformID": {
            "type": "USHORT",
            "value": 0
          },
          "encodingID": {
            "type": "USHORT",
            "value": 6
          },
          "offset": {
            "type": "ULONG",
            "value": 16
          },
          "format": {
            "type": "USHORT",
            "value": 4
          },
          "cmap4Length": {
            "type": "USHORT",
            "value": 16
          },
          "language": {
            "type": "USHORT",
            "value": 0
          },
          "segCountX2": {
            "type": "USHORT",
            "value": 2
          },
          "searchRange": {
            "type": "USHORT",
            "value": 2
          },
          "entrySelector": {
            "type": "USHORT",
            "value": 0
          },
          "rangeShift": {
            "type": "USHORT",
            "value": 0
          },
          "end_0": {
            "type": "USHORT",
            "value": 65535
          },
          "reservedPad": {
            "type": "USHORT",
            "value": 0
          },
          "start_0": {
            "type": "USHORT",
            "value": 65535
          },
          "idDelta_0": {
            "type": "SHORT",
            "value": 1
          },
          "idRangeOffset_0": {
            "type": "USHORT",
            "value": 0
          }
        }
      }
    },
    "head table": {
      "type": "RECORD",
      "value": {
        "name": "head",
        "fields": {
          "version": {
            "type": "FIXED",
            "value": 65536
          },
          "fontRevision": {
            "type": "FIXED",
            "value": 65536
          },
          "checkSumAdjustment": {
            "type": "ULONG",
            "value": 0
          },
          "magicNumber": {
            "type": "ULONG",
            "value": 1594834165
          },
          "flags": {
            "type": "USHORT",
            "value": 3
          },
          "unitsPerEm": {
            "type": "USHORT",
            "value": 1000
          },
          "created": {
            "type": "LONGDATETIME",
            "value": 3630507805
          },
          "modified": {
            "type": "LONGDATETIME",
            "value": 3630507805
          },
          "xMin": {
            "type": "SHORT",
            "value": null
          },
          "yMin": {
            "type": "SHORT",
            "value": null
          },
          "xMax": {
            "type": "SHORT",
            "value": null
          },
          "yMax": {
            "type": "SHORT",
            "value": null
          },
          "macStyle": {
            "type": "USHORT",
            "value": 0
          },
          "lowestRecPPEM": {
            "type": "USHORT",
            "value": 3
          },
          "fontDirectionHint": {
            "type": "SHORT",
            "value": 2
          },
          "indexToLocFormat": {
            "type": "SHORT",
            "value": 0
          },
          "glyphDataFormat": {
            "type": "SHORT",
            "value": 0
          }
        }
      }
    },
    "padding_3": {
      "type": "BYTE",
      "value": 0
    },
    "padding_4": {
      "type": "BYTE",
      "value": 0
    },
    "hhea table": {
      "type": "RECORD",
      "value": {
        "name": "hhea",
        "fields": {
          "version": {
            "type": "FIXED",
            "value": 65536
          },
          "ascender": {
            "type": "FWORD",
            "value": 200
          },
          "descender": {
            "type": "FWORD",
            "value": 100
          },
          "lineGap": {
            "type": "FWORD",
            "value": 0
          },
          "advanceWidthMax": {
            "type": "UFWORD",
            "value": null
          },
          "minLeftSideBearing": {
            "type": "FWORD",
            "value": null
          },
          "minRightSideBearing": {
            "type": "FWORD",
            "value": null
          },
          "xMaxExtent": {
            "type": "FWORD",
            "value": null
          },
          "caretSlopeRise": {
            "type": "SHORT",
            "value": 1
          },
          "caretSlopeRun": {
            "type": "SHORT",
            "value": 0
          },
          "caretOffset": {
            "type": "SHORT",
            "value": 0
          },
          "reserved1": {
            "type": "SHORT",
            "value": 0
          },
          "reserved2": {
            "type": "SHORT",
            "value": 0
          },
          "reserved3": {
            "type": "SHORT",
            "value": 0
          },
          "reserved4": {
            "type": "SHORT",
            "value": 0
          },
          "metricDataFormat": {
            "type": "SHORT",
            "value": 0
          },
          "numberOfHMetrics": {
            "type": "USHORT",
            "value": 0
          }
        }
      }
    },
    "hmtx table": {
      "type": "RECORD",
      "value": {
        "name": "hmtx",
        "fields": {}
      }
    },
    "maxp table": {
      "type": "RECORD",
      "value": {
        "name": "maxp",
        "fields": {
          "version": {
            "type": "FIXED",
            "value": 20480
          },
          "numGlyphs": {
            "type": "USHORT",
            "value": 0
          }
        }
      }
    },
    "padding_5": {
      "type": "BYTE",
      "value": 0
    },
    "padding_6": {
      "type": "BYTE",
      "value": 0
    },
    "name table": {
      "type": "RECORD",
      "value": {
        "name": "name",
        "fields": {
          "format": {
            "type": "USHORT",
            "value": 0
          },
          "count": {
            "type": "USHORT",
            "value": 0
          },
          "stringOffset": {
            "type": "USHORT",
            "value": 6
          },
          "strings": {
            "type": "LITERAL",
            "value": []
          }
        }
      }
    },
    "padding_7": {
      "type": "BYTE",
      "value": 0
    },
    "padding_8": {
      "type": "BYTE",
      "value": 0
    },
    "OS/2 table": {
      "type": "RECORD",
      "value": {
        "name": "OS/2",
        "fields": {
          "version": {
            "type": "USHORT",
            "value": 5
          },
          "xAvgCharWidth": {
            "type": "SHORT",
            "value": 0
          },
          "usWeightClass": {
            "type": "USHORT",
            "value": 0
          },
          "usWidthClass": {
            "type": "USHORT",
            "value": 0
          },
          "fsType": {
            "type": "USHORT",
            "value": 0
          },
          "ySubscriptXSize": {
            "type": "SHORT",
            "value": 650
          },
          "ySubscriptYSize": {
            "type": "SHORT",
            "value": 699
          },
          "ySubscriptXOffset": {
            "type": "SHORT",
            "value": 0
          },
          "ySubscriptYOffset": {
            "type": "SHORT",
            "value": 140
          },
          "ySuperscriptXSize": {
            "type": "SHORT",
            "value": 650
          },
          "ySuperscriptYSize": {
            "type": "SHORT",
            "value": 699
          },
          "ySuperscriptXOffset": {
            "type": "SHORT",
            "value": 0
          },
          "ySuperscriptYOffset": {
            "type": "SHORT",
            "value": 479
          },
          "yStrikeoutSize": {
            "type": "SHORT",
            "value": 49
          },
          "yStrikeoutPosition": {
            "type": "SHORT",
            "value": 258
          },
          "sFamilyClass": {
            "type": "SHORT",
            "value": 0
          },
          "bFamilyType": {
            "type": "BYTE",
            "value": 0
          },
          "bSerifStyle": {
            "type": "BYTE",
            "value": 0
          },
          "bWeight": {
            "type": "BYTE",
            "value": 0
          },
          "bProportion": {
            "type": "BYTE",
            "value": 0
          },
          "bContrast": {
            "type": "BYTE",
            "value": 0
          },
          "bStrokeVariation": {
            "type": "BYTE",
            "value": 0
          },
          "bArmStyle": {
            "type": "BYTE",
            "value": 0
          },
          "bLetterform": {
            "type": "BYTE",
            "value": 0
          },
          "bMidline": {
            "type": "BYTE",
            "value": 0
          },
          "bXHeight": {
            "type": "BYTE",
            "value": 0
          },
          "ulUnicodeRange1": {
            "type": "ULONG",
            "value": 0
          },
          "ulUnicodeRange2": {
            "type": "ULONG",
            "value": 0
          },
          "ulUnicodeRange3": {
            "type": "ULONG",
            "value": 0
          },
          "ulUnicodeRange4": {
            "type": "ULONG",
            "value": 0
          },
          "achVendID": {
            "type": "CHARARRAY",
            "value": "XXXX"
          },
          "fsSelection": {
            "type": "USHORT",
            "value": 0
          },
          "usFirstCharIndex": {
            "type": "USHORT",
            "value": 0
          },
          "usLastCharIndex": {
            "type": "USHORT",
            "value": 0
          },
          "sTypoAscender": {
            "type": "SHORT",
            "value": 0
          },
          "sTypoDescender": {
            "type": "SHORT",
            "value": 0
          },
          "sTypoLineGap": {
            "type": "SHORT",
            "value": 0
          },
          "usWinAscent": {
            "type": "USHORT",
            "value": 0
          },
          "usWinDescent": {
            "type": "USHORT",
            "value": 0
          },
          "ulCodePageRange1": {
            "type": "ULONG",
            "value": 0
          },
          "ulCodePageRange2": {
            "type": "ULONG",
            "value": 0
          },
          "sxHeight": {
            "type": "SHORT",
            "value": 0
          },
          "sCapHeight": {
            "type": "SHORT",
            "value": 0
          },
          "usDefaultChar": {
            "type": "USHORT",
            "value": 0
          },
          "usBreakChar": {
            "type": "USHORT",
            "value": 0
          },
          "usMaxContext": {
            "type": "USHORT",
            "value": 0
          },
          "usLowerOpticalPointSize": {
            "type": "USHORT",
            "value": 0
          },
          "usUpperOpticalPointSize": {
            "type": "USHORT",
            "value": 0
          }
        }
      }
    },
    "post table": {
      "type": "RECORD",
      "value": {
        "name": "post",
        "fields": {
          "version": {
            "type": "FIXED",
            "value": 196608
          },
          "italicAngle": {
            "type": "FIXED",
            "value": 0
          },
          "underlinePosition": {
            "type": "FWORD",
            "value": 0
          },
          "underlineThickness": {
            "type": "FWORD",
            "value": 0
          },
          "isFixedPitch": {
            "type": "ULONG",
            "value": 0
          },
          "minMemType42": {
            "type": "ULONG",
            "value": 0
          },
          "maxMemType42": {
            "type": "ULONG",
            "value": 0
          },
          "minMemType1": {
            "type": "ULONG",
            "value": 0
          },
          "maxMemType1": {
            "type": "ULONG",
            "value": 0
          }
        }
      }
    }
  }
}

这些是十进制值，用于为其中一种轻微变化创建输出字节：

79 84 84 79 
0 9 0 8 
0 3 0 1 
67 70 70 32 (1)
0 0 0 0 
0 0 0 156 
0 0 0 5 
99 109 97 112 (2)
0 0 0 0 
0 0 0 164 
0 0 0 36 
104 101 97 100 (3)
0 0 0 0 
0 0 0 200 
0 0 0 54 
104 104 101 97 (4)
0 0 0 0 
0 0 1 0 
0 0 0 36 
104 109 116 120 (5)
0 0 0 0 
0 0 1 36 
0 0 0 0 
109 97 120 112 (6)
0 0 0 0 
0 0 1 36 
0 0 0 6 
110 97 109 101 (7)
0 0 0 0 
0 0 1 44 
0 0 0 6 
79 83 47 50 (8)
0 0 0 0 
0 0 1 52 
0 0 0 100 
112 111 115 116 (9)
0 0 0 0 
0 0 1 152 
0 0 0 32 
2 0 4 0 (CFF start)
0 0 0 0 (4-align with three 0's)
0 0 0 1 (cmap start)
0 0 0 6 
0 0 0 16 
0 4 0 16 
0 0 0 2 0 2 0 0 0 0 255 255 0 0 255 255 0 1 0 0 0 1 0 0 0 1 0 0 0 0 0 0 95 15 60 245 0 3 3 232 0 0 0 0 216 101 49 90 0 0 0 0 216 101 49 90 0 0 0 0 0 0 0 0 0 0 0 3 0 2 0 0 0 0 0 0 0 1 0 0 0 200 0 100 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 80 0 0 0 0 0 0 0 0 0 0 6 0 0 0 5 0 0 0 0 0 0 0 0 2 138 2 187 0 0 0 140 2 138 2 187 0 0 1 223 0 49 1 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 88 88 88 88 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

似乎表明它是对齐的，所以我听不懂。希望有所帮助。

Answer 1

在调试输出时，您可能会发现使用十六进制转储格式很有用，该格式在右列中显示字节的ASCII表示形式。为此，我使用xxd，并建议您也这样做。特别是对于OpenType字体，这种转储格式非常适合发现对齐问题，尤其是在字体标题中。

明白我的意思：这是您其中一个转储的第一部分：

00000000: 4f54 544f 0009 0008 0003 0001 4346 4620  OTTO........CFF 
00000010: 0000 0000 0000 00c2 9c00 0000 0563 6d61  .............cma
00000020: 7000 0000 0000 0000 c2a4 0000 0024 6865  p............$he
00000030: 6164 0000 0000 0000 00c3 8800 0000 3668  ad............6h
00000040: 6865 6100 0000 0000 0001 0000 0000 2468  hea...........$h
00000050: 6d74 7800 0000 0000 0001 2400 0000 006d  mtx.......$....m
00000060: 6178 7000 0000 0000 0001 2400 0000 066e  axp.......$....n
00000070: 616d 6500 0000 0000 0001 2c00 0000 064f  ame.......,....O
00000080: 532f 3200 0000 0000 0001 3400 0000 6470  S/2.......4...dp
00000090: 6f73 7400 0000 0000 0001 c298 0000 0020  ost............

您可以看到，对于CFF表的第一个tableDirectory条目，标记（'CFF'）从第一行（4346 4620，即ASCII），那是正确的对齐方式。因为hexdump行的长度正好是16个字节，并且因为每个tableDirectory条目都是16个字节，所以正确对齐的tableDirectory将把每个表的标记作为行的最后4个字节。但是正如您所看到的，您有一些未对齐的地方……“ cmap”的“ c”（0x63）向右偏右一个字节，并且随后的tableDirectory条目也被移位。应该看起来更像这样：

00000000: 4f54 544f 0009 0008 0003 0001 4346 4620  OTTO........CFF 
00000010: ???? ???? ???? ???? ???? ???? 636d 6170  ............cmap
00000020: ???? ???? ???? ???? ???? ???? 6865 6164  ............head
00000030: ???? ???? ???? ???? ???? ???? 6868 6561  ............hhea
[...]

因此，对于您的tableDirectory条目中的 some 来说，它的末尾添加了一个额外的字节。因此，您需要备份并检查该代码，然后使其首先正常运行，然后再担心searchRange，rangeShift和entrySelector（假设您的字体包含所宣传的9个表，它们应为：0080 0003 0010（十六进制））。

OpenType字体的表格未对齐错误

1 个答案: