Module fontai.io.formats

This module contains classes that deal with encoding/decoding bytestreams from/to the data formats that act as the interface between pipeline stages and storage, and between different ML pipeline stages.

"""This module contains classes that deal with encoding/decoding bytestreams from/to the data formats that act as the interface between pipeline stages and storage, and between different ML pipeline stages.

"""
from __future__ import annotations
import zipfile
import sys
import typing as t
import logging
import io
from abc import ABC, abstractmethod

from pydantic import BaseModel

from numpy import ndarray
import imageio
from PIL import ImageFont


#from tensorflow import string as tf_str
#from tensorflow.train import (Example as TFExample, Feature as TFFeature, Features as TFFeatures, BytesList as TFBytesList)

from tensorflow.io import FixedLenFeature, parse_single_example
from fontai.io.storage import BytestreamPath

logger = logging.getLogger(__name__)


class InMemoryFile(BaseModel):

  """Wrapper class for retrieved file bytestreams
  """

  filename: str
  content: bytes


  def to_format(self, file_format: InMemoryFile) -> InMemoryFile:
    """Cast instance as a different file type inehriting from InMemoryFile 
    
    Args:
        file_format (InMemoryFile): Target file type
    
    Returns:
        InMemoryFile: cast file instance.
    """
    return file_format(**self.dict())

  def deserialise(self):
    """Parse instance as the corresponding Python object such as a ZipFile or an ImageFont.truetype
    
    """
    return self

  @classmethod
  def from_file(cls, filepath: str) -> InMemoryFile:
    """Instantiate from file path
    
    Args:
        filepath (str): FIle path
    
    Returns:
        InMemoryFile: instantiated object
    """
    return cls(filename = filepath, content = BytestreamPath(filepath).read_bytes())

  @classmethod
  def from_bytestream_path(cls, bsp: BytestreamPath) -> InMemoryFile:
    """Instantiate from bytestream path
    
    Returns:
        InMemoryFile: instantiated object
    
    """
    return cls(filename = str(bsp), content = bsp.read_bytes())

  @classmethod
  def serialise(cls, obj: t.Any):
    """Serialises a Python object to an instance of InMemoryFile
    
    Args:
        obj (t.Any): Python object
    
    Returns:
        InMemoryFile: Description
    
    Raises:
        TypeError: If passed object is not an instance of InMemoryFile
    """
    if not isinstance(obj, InMemoryFile):
      raise TypeError("InMemoryFile only can be serialised from an instance of the same class.")
    else:
      return obj

  def __str__(self):
    return f"Filename: {self.filename}, content size: {sys.getsizeof(self.content)/1e6} MB."



class InMemoryZipfile(InMemoryFile):

  """In-memory buffer class for ingested zip bytestream
  """
  
  def deserialise(self):
    """
    
    Returns:
        zipfile.ZipFile: An open ZipFile instance with the current instance's contents
    """
    return zipfile.ZipFile(io.BytesIO(self.content),"r")

  @classmethod
  def serialise(self, obj: zipfile.ZipFile):
    raise NotImplementError("Serialisation to InMemoryZipfile is not implemented.")
    # bf = io.BytesIO()
    # zipped = zipfile.ZipFile(bf,"w")
    # for file in obj.filelist():
    #   zipped.writestr(file, obj.read(file))

    # return InMemoryZipfile(filename="holder", content = bf.getvalue())



class InMemoryFontfile(InMemoryFile):

  """In-memory buffer class for ingested ttf or otf font files
  """
  
  def deserialise(self, font_size: int):
    """
    Args:
        font_size (int)
    
    No Longer Returned:
        font: A parsed font object.
    """
    return ImageFont.truetype(io.BytesIO(self.content),font_size)

  def serialise(self, font: ImageFont.FreeTypeFont):
    raise NotImplementError("Serialisation to InMemoryFontfile is not implemented.")

Classes

class InMemoryFile (**data: Any)

Wrapper class for retrieved file bytestreams

Create a new model by parsing and validating input data from keyword arguments.

Raises ValidationError if the input data cannot be parsed to form a valid model.

Expand source code

class InMemoryFile(BaseModel):

  """Wrapper class for retrieved file bytestreams
  """

  filename: str
  content: bytes


  def to_format(self, file_format: InMemoryFile) -> InMemoryFile:
    """Cast instance as a different file type inehriting from InMemoryFile 
    
    Args:
        file_format (InMemoryFile): Target file type
    
    Returns:
        InMemoryFile: cast file instance.
    """
    return file_format(**self.dict())

  def deserialise(self):
    """Parse instance as the corresponding Python object such as a ZipFile or an ImageFont.truetype
    
    """
    return self

  @classmethod
  def from_file(cls, filepath: str) -> InMemoryFile:
    """Instantiate from file path
    
    Args:
        filepath (str): FIle path
    
    Returns:
        InMemoryFile: instantiated object
    """
    return cls(filename = filepath, content = BytestreamPath(filepath).read_bytes())

  @classmethod
  def from_bytestream_path(cls, bsp: BytestreamPath) -> InMemoryFile:
    """Instantiate from bytestream path
    
    Returns:
        InMemoryFile: instantiated object
    
    """
    return cls(filename = str(bsp), content = bsp.read_bytes())

  @classmethod
  def serialise(cls, obj: t.Any):
    """Serialises a Python object to an instance of InMemoryFile
    
    Args:
        obj (t.Any): Python object
    
    Returns:
        InMemoryFile: Description
    
    Raises:
        TypeError: If passed object is not an instance of InMemoryFile
    """
    if not isinstance(obj, InMemoryFile):
      raise TypeError("InMemoryFile only can be serialised from an instance of the same class.")
    else:
      return obj

  def __str__(self):
    return f"Filename: {self.filename}, content size: {sys.getsizeof(self.content)/1e6} MB."

Ancestors

• pydantic.main.BaseModel
• pydantic.utils.Representation

Subclasses

• InMemoryFontfile
• InMemoryZipfile

Class variables

var content : bytes

var filename : str

Static methods

def from_bytestream_path(bsp: BytestreamPath) ‑> InMemoryFile

Instantiate from bytestream path

Returns

InMemoryFile

instantiated object

Expand source code

@classmethod
def from_bytestream_path(cls, bsp: BytestreamPath) -> InMemoryFile:
  """Instantiate from bytestream path
  
  Returns:
      InMemoryFile: instantiated object
  
  """
  return cls(filename = str(bsp), content = bsp.read_bytes())

def from_file(filepath: str) ‑> InMemoryFile

Instantiate from file path

Args

filepath : str

FIle path

Returns

InMemoryFile

instantiated object

Expand source code

@classmethod
def from_file(cls, filepath: str) -> InMemoryFile:
  """Instantiate from file path
  
  Args:
      filepath (str): FIle path
  
  Returns:
      InMemoryFile: instantiated object
  """
  return cls(filename = filepath, content = BytestreamPath(filepath).read_bytes())

def serialise(obj: t.Any)

Serialises a Python object to an instance of InMemoryFile

Args

obj : t.Any

Python object

Returns

InMemoryFile

Description

Raises

TypeError

If passed object is not an instance of InMemoryFile

Expand source code

@classmethod
def serialise(cls, obj: t.Any):
  """Serialises a Python object to an instance of InMemoryFile
  
  Args:
      obj (t.Any): Python object
  
  Returns:
      InMemoryFile: Description
  
  Raises:
      TypeError: If passed object is not an instance of InMemoryFile
  """
  if not isinstance(obj, InMemoryFile):
    raise TypeError("InMemoryFile only can be serialised from an instance of the same class.")
  else:
    return obj

Methods

def deserialise(self)

Parse instance as the corresponding Python object such as a ZipFile or an ImageFont.truetype

Expand source code

def deserialise(self):
  """Parse instance as the corresponding Python object such as a ZipFile or an ImageFont.truetype
  
  """
  return self

def to_format(self, file_format: InMemoryFile) ‑> InMemoryFile

Cast instance as a different file type inehriting from InMemoryFile

Args

file_format : InMemoryFile

Target file type

Returns

InMemoryFile

cast file instance.

Expand source code

def to_format(self, file_format: InMemoryFile) -> InMemoryFile:
  """Cast instance as a different file type inehriting from InMemoryFile 
  
  Args:
      file_format (InMemoryFile): Target file type
  
  Returns:
      InMemoryFile: cast file instance.
  """
  return file_format(**self.dict())

class InMemoryFontfile (**data: Any)

In-memory buffer class for ingested ttf or otf font files

Create a new model by parsing and validating input data from keyword arguments.

Raises ValidationError if the input data cannot be parsed to form a valid model.

Expand source code

class InMemoryFontfile(InMemoryFile):

  """In-memory buffer class for ingested ttf or otf font files
  """
  
  def deserialise(self, font_size: int):
    """
    Args:
        font_size (int)
    
    No Longer Returned:
        font: A parsed font object.
    """
    return ImageFont.truetype(io.BytesIO(self.content),font_size)

  def serialise(self, font: ImageFont.FreeTypeFont):
    raise NotImplementError("Serialisation to InMemoryFontfile is not implemented.")

Ancestors

• InMemoryFile
• pydantic.main.BaseModel
• pydantic.utils.Representation

Class variables

var content : bytes

var filename : str

Methods

def deserialise(self, font_size: int)

Args

font_size (int) No Longer Returned: font: A parsed font object.

Expand source code

def deserialise(self, font_size: int):
  """
  Args:
      font_size (int)
  
  No Longer Returned:
      font: A parsed font object.
  """
  return ImageFont.truetype(io.BytesIO(self.content),font_size)

Inherited members

• InMemoryFile:
  • from_bytestream_path
  • from_file
  • serialise
  • to_format

class InMemoryZipfile (**data: Any)

In-memory buffer class for ingested zip bytestream

Create a new model by parsing and validating input data from keyword arguments.

Raises ValidationError if the input data cannot be parsed to form a valid model.

Expand source code

class InMemoryZipfile(InMemoryFile):

  """In-memory buffer class for ingested zip bytestream
  """
  
  def deserialise(self):
    """
    
    Returns:
        zipfile.ZipFile: An open ZipFile instance with the current instance's contents
    """
    return zipfile.ZipFile(io.BytesIO(self.content),"r")

  @classmethod
  def serialise(self, obj: zipfile.ZipFile):
    raise NotImplementError("Serialisation to InMemoryZipfile is not implemented.")
    # bf = io.BytesIO()
    # zipped = zipfile.ZipFile(bf,"w")
    # for file in obj.filelist():
    #   zipped.writestr(file, obj.read(file))

    # return InMemoryZipfile(filename="holder", content = bf.getvalue())

Ancestors

• InMemoryFile
• pydantic.main.BaseModel
• pydantic.utils.Representation

Class variables

var content : bytes

var filename : str

Methods

def deserialise(self)

Returns

zipfile.ZipFile

An open ZipFile instance with the current instance's contents

Expand source code

def deserialise(self):
  """
  
  Returns:
      zipfile.ZipFile: An open ZipFile instance with the current instance's contents
  """
  return zipfile.ZipFile(io.BytesIO(self.content),"r")

Inherited members

• InMemoryFile:
  • from_bytestream_path
  • from_file
  • serialise
  • to_format