# woff2: Read and write the WOFF2 font file format

Note also that `woff2` supports some optional external libraries.

class fontTools.ttLib.woff2.WOFF2Reader(*args, **kwargs)

  Bases: `SFNTReader`

  flavor = 'woff2'
  reconstructTable(tag)

    Reconstruct table named ‘tag’ from transformed data.

class fontTools.ttLib.woff2.WOFF2Writer(*args, **kwargs)

  Bases: `SFNTWriter`

  flavor = 'woff2'
  close()

    All tags must have been specified. Now write the table data and directory.

  transformTable(tag)

    Return transformed table data, or None if some pre-conditions aren’t met – in which case, the non-transformed table data will be used.

  writeMasterChecksum()

    Write checkSumAdjustment to the transformBuffer.

  reordersTables()

fontTools.ttLib.woff2.getKnownTagIndex(tag)

  Return index of ‘tag’ in woff2KnownTags list. Return 63 if not found.

class fontTools.ttLib.woff2.WOFF2DirectoryEntry

  Bases: `DirectoryEntry`

  fromFile(file)
  fromString(data)
  toString()
  property transformVersion

    Return bits 6-7 of table entry’s flags, which indicate the preprocessing transformation version number (between 0 and 3).

  property transformed

    Return True if the table has any transformation, else return False.

class fontTools.ttLib.woff2.WOFF2LocaTable(tag=None)

  Bases: `table__l_o_c_a`

  Same as parent class. The only difference is that it attempts to preserve the ‘indexFormat’ as encoded in the WOFF2 glyf table.

  compile(ttFont)

class fontTools.ttLib.woff2.WOFF2GlyfTable(tag=None)

  Bases: `table__g_l_y_f`

  Decoder/Encoder for WOFF2 ‘glyf’ table transform.

  subStreams = ('nContourStream', 'nPointsStream', 'flagStream', 'glyphStream', 'compositeStream', 'bboxStream', 'instructionStream')
  reconstruct(data, ttFont)

    Decompile transformed ‘glyf’ data.

  transform(ttFont)

    Return transformed ‘glyf’ data

class fontTools.ttLib.woff2.WOFF2HmtxTable(tag=None)

  Bases: `table__h_m_t_x`

  reconstruct(data, ttFont)
  transform(ttFont)

class fontTools.ttLib.woff2.WOFF2FlavorData(reader=None, data=None, transformedTables=None)

  Bases: `WOFFFlavorData`

  Flavor = 'woff2'

fontTools.ttLib.woff2.unpackBase128(data)

  Read one to five bytes from UIntBase128-encoded input string, and return a tuple containing the decoded integer plus any leftover data.

      >>> unpackBase128(b'\x3f\x00\x00') == (63, b"\x00\x00")
      True
      >>> unpackBase128(b'\x8f\xff\xff\xff\x7f')[0] == 4294967295
      True
      >>> unpackBase128(b'\x80\x80\x3f')
      Traceback (most recent call last):
        File "<stdin>", line 1, in ?
      TTLibError: UIntBase128 value must not start with leading zeros
      >>> unpackBase128(b'\x8f\xff\xff\xff\xff\x7f')[0]
      Traceback (most recent call last):
        File "<stdin>", line 1, in ?
      TTLibError: UIntBase128-encoded sequence is longer than 5 bytes
      >>> unpackBase128(b'\x90\x80\x80\x80\x00')[0]
      Traceback (most recent call last):
        File "<stdin>", line 1, in ?
      TTLibError: UIntBase128 value exceeds 2**32-1

fontTools.ttLib.woff2.base128Size(n)

  Return the length in bytes of a UIntBase128-encoded sequence with value n.

      >>> base128Size(0)
      1
      >>> base128Size(24567)
      3
      >>> base128Size(2**32-1)
      5

fontTools.ttLib.woff2.packBase128(n)

  Encode unsigned integer in range 0 to 2**32-1 (inclusive) to a string of bytes using UIntBase128 variable-length encoding. Produce the shortest possible encoding.

      >>> packBase128(63) == b"\x3f"
      True
      >>> packBase128(2**32-1) == b'\x8f\xff\xff\xff\x7f'
      True

fontTools.ttLib.woff2.unpack255UShort(data)

  Read one to three bytes from 255UInt16-encoded input string, and return a tuple containing the decoded integer plus any leftover data.

      >>> unpack255UShort(bytechr(252))[0]
      252

  Note that some numbers (e.g. 506) can have multiple encodings: >>> unpack255UShort(struct.pack(“BB”, 254, 0))[0] 506 >>> unpack255UShort(struct.pack(“BB”, 255, 253))[0] 506 >>> unpack255UShort(struct.pack(“BBB”, 253, 1, 250))[0] 506

fontTools.ttLib.woff2.pack255UShort(value)

  Encode unsigned integer in range 0 to 65535 (inclusive) to a bytestring using 255UInt16 variable-length encoding.

      >>> pack255UShort(252) == b'\xfc'
      True
      >>> pack255UShort(506) == b'\xfe\x00'
      True
      >>> pack255UShort(762) == b'\xfd\x02\xfa'
      True

fontTools.ttLib.woff2.compress(input_file, output_file, transform_tables=None)

  Compress OpenType font to WOFF2.

  Parameters:

    - input_file – a file path, file or file-like object (open in binary mode) containing an OpenType font (either CFF- or TrueType-flavored).

    - output_file – a file path, file or file-like object where to save the compressed WOFF2 font.

    - transform_tables – Optional[Iterable[str]]: a set of table tags for which to enable preprocessing transformations. By default, only ‘glyf’ and ‘loca’ tables are transformed. An empty set means disable all transformations.

fontTools.ttLib.woff2.decompress(input_file, output_file)

  Decompress WOFF2 font to OpenType font.

  Parameters:

    - input_file – a file path, file or file-like object (open in binary mode) containing a compressed WOFF2 font.

    - output_file – a file path, file or file-like object where to save the decompressed OpenType font.

fontTools.ttLib.woff2.main(args=None)

  Compress and decompress WOFF2 fonts