Drop Py37, improve typing and docstrings (#544)

Drops Py3.7, improves typing and adds a mypy config, improves the docstrings and isorts the imports.

* configure isort
* sort with isort
* add github action
* enable flake8-docstrings
* fix docstrings
* add mypy env
* no implicit optional
* add type for raw
* add some type hints

.github/workflows/pythonpackage.yml

@@ -30,6 +30,11 @@ jobs:
         python -m pip install --upgrade pip
         pip install flake8 pytest tox tox-gh-actions
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+    - name: Check sorting of imports
+      uses: isort/isort-action@master
+      with:
+        requirementsFiles: "requirements.txt doc/requirements.txt"
+        sortPaths: "./doc ./src ./examples ./test ./setup.py"
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names

doc/conf.py

@@ -12,9 +12,8 @@
 # All configuration values have a default; values that are commented out
 # serve to show the default.
 
-import sys
 import os
-
+import sys
 from importlib.metadata import version as imp_version
 
 on_rtd = os.getenv("READTHEDOCS") == "True"

examples/barcodes.py

@@ -1,6 +1,6 @@
+"""Example for printing barcodes."""
 from escpos.printer import Usb
 
-
 # Adapt to your needs
 p = Usb(0x0416, 0x5011, profile="TM-T88II")
 

examples/codepage_tables.py

@@ -1,23 +1,24 @@
-"""Prints code page tables.
+"""Prints code page tables."""
-"""
 
 
+import sys
+
 import six
-import sys
 
 from escpos import printer
 from escpos.constants import (
     CODEPAGE_CHANGE,
-    ESC,
-    CTL_LF,
-    CTL_FF,
     CTL_CR,
+    CTL_FF,
     CTL_HT,
+    CTL_LF,
     CTL_VT,
+    ESC,
 )
 
 
 def main():
+    """Init printer and print codepage tables."""
     dummy = printer.Dummy()
 
     dummy.hw("init")
@@ -34,6 +35,7 @@ def main():
 
 
 def print_codepage(printer, codepage):
+    """Print a codepage."""
     if codepage.isdigit():
         codepage = int(codepage)
         printer._raw(CODEPAGE_CHANGE + six.int2byte(codepage))

examples/docker-flask/app.py

@@ -1,12 +1,15 @@
-from escpos.printer import CupsPrinter
+"""Example for a flask application."""
 from flask import Flask
 
+from escpos.printer import CupsPrinter
+
 # Initialize Flask app
 app = Flask(__name__)
 
 
 @app.route("/", methods=["GET"])
 def do_print():
+    """Print."""
     # p = Usb(0x04b8, 0x0e28, 0)
     p = CupsPrinter(host="localhost", port=631, printer_name="TM-T20III")
     p.text("Hello World\n")

examples/docker-flask/requirements.txt

@@ -3,7 +3,6 @@ argcomplete==3.0.8
 blinker==1.6.2
 click==8.1.3
 Flask==2.3.2
-future==0.18.3
 itsdangerous==2.1.2
 Jinja2==3.1.2
 MarkupSafe==2.1.2

examples/qr_code.py

@@ -1,9 +1,11 @@
+"""Print example QR codes."""
 import sys
 
 from escpos.printer import Usb
 
 
 def usage():
+    """Print information on usage."""
     print("usage: qr_code.py <content>")
 
 

examples/software_barcode.py

@@ -1,6 +1,6 @@
+"""Example file for software barcodes."""
 from escpos.printer import Usb
 
-
 # Adapt to your needs
 p = Usb(0x0416, 0x5011, profile="POS-5890")
 

examples/weather.py

@@ -1,28 +1,29 @@
 #!/usr/bin/python
+"""Weather forecast example.
+
+Adapted script from Adafruit
+Weather forecast for Raspberry Pi w/Adafruit Mini Thermal Printer.
+Retrieves data from DarkSky.net's API, prints current conditions and
+forecasts for next two days.
+Weather example using nice bitmaps.
+Written by Adafruit Industries.  MIT license.
+Adapted and enhanced for escpos library by MrWunderbar666
+
+Icons taken from https://adamwhitcroft.com/climacons/
+Check out his github: https://github.com/AdamWhitcroft/climacons
+"""
 
 
-# Adapted script from Adafruit
-# Weather forecast for Raspberry Pi w/Adafruit Mini Thermal Printer.
-# Retrieves data from DarkSky.net's API, prints current conditions and
-# forecasts for next two days.
-# Weather example using nice bitmaps.
-# Written by Adafruit Industries.  MIT license.
-# Adapted and enhanced for escpos library by MrWunderbar666
-
-# Icons taken from https://adamwhitcroft.com/climacons/
-# Check out his github: https://github.com/AdamWhitcroft/climacons
-
-
-from datetime import datetime
 import calendar
-import urllib
 import json
-import time
 import os
+import time
+import urllib
+from datetime import datetime
 
 from escpos.printer import Usb
 
-""" Setting up the main pathing """
+"""Set up the main pathing."""
 this_dir, this_filename = os.path.split(__file__)
 GRAPHICS_PATH = os.path.join(this_dir, "graphics/climacons/")
 
@@ -38,13 +39,14 @@ LONG = "114.189945"  # Your Location
 
 
 def forecast_icon(idx):
+    """Get right icon for forecast."""
     icon = data["daily"]["data"][idx]["icon"]
     image = GRAPHICS_PATH + icon + ".png"
     return image
 
 
-# Dumps one forecast line to the printer
 def forecast(idx):
+    """Dump one forecast line to the printer."""
     date = datetime.fromtimestamp(int(data["daily"]["data"][idx]["time"]))
     day = calendar.day_name[date.weekday()]
     lo = data["daily"]["data"][idx]["temperatureMin"]
@@ -73,6 +75,7 @@ def forecast(idx):
 
 
 def icon():
+    """Get icon."""
     icon = data["currently"]["icon"]
     image = GRAPHICS_PATH + icon + ".png"
     return image

pyproject.toml

@@ -1,3 +1,15 @@
 [tool.black]
 extend-exclude = 'capabilities-data'
 
+[tool.isort]
+profile = "black"
+
+[tool.pytest.ini_options]
+minversion = "6.0"
+addopts = "--doctest-modules --cov escpos --cov-report=xml"
+testpaths = [
+    "test",
+    "src",
+    "src/escpos",
+    "escpos",
+]

setup.cfg

@@ -31,7 +31,7 @@ project_urls =
     Release Notes = https://github.com/python-escpos/python-escpos/releases
 
 [options]
-python_requires = >=3.6
+python_requires = >=3.8
 zip_safe = false
 include_package_data = true
 install_requires =
@@ -46,7 +46,6 @@ install_requires =
     PyYAML
     argparse
     argcomplete
-    future
     importlib_resources
 setup_requires = setuptools_scm
 tests_require =
@@ -65,4 +64,3 @@ tests_require =
 exclude = .git,.tox,.github,.eggs,__pycache__,doc/conf.py,build,dist,capabilities-data,test,src/escpos/constants.py
 max-line-length = 120
 extend-ignore = E203, W503
-# future-imports = absolute_import, division, print_function, unicode_literals  # we are not there yet

setup.py

@@ -1,9 +1,10 @@
 #!/usr/bin/env python
+"""Setup script for python package."""
 
 import os
 import sys
-from setuptools import find_packages, setup
 
+from setuptools import find_packages, setup
 
 base_dir = os.path.dirname(__file__)
 src_dir = os.path.join(base_dir, "src")
@@ -14,14 +15,18 @@ sys.path.insert(0, src_dir)
 
 
 def read(fname):
-    """read file from same path as setup.py"""
+    """Read file from same path as setup.py."""
     return open(os.path.join(os.path.dirname(__file__), fname)).read()
 
 
 setuptools_scm_template = """\
-# coding: utf-8
+#!/usr/bin/python
-# file generated by setuptools_scm
+#  -*- coding: utf-8 -*-
-# don't change, don't track in version control
+\"\"\"Version identifier.
+
+file generated by setuptools_scm
+don't change, don't track in version control
+\"\"\"
 
 version = '{version}'
 """

src/escpos/__init__.py

@@ -1,7 +1,5 @@
 # -*- coding: utf-8 -*-
-"""
+"""python-escpos enables you to manipulate escpos-printers."""
-python-escpos enables you to manipulate escpos-printers
-"""
 
 __all__ = ["constants", "escpos", "exceptions", "printer"]
 

src/escpos/capabilities.py

@@ -1,20 +1,19 @@
-import re
+"""Handler for capabilities data."""
-from os import environ, path
 import atexit
-import pickle
 import logging
+import pickle
+import platform
+import re
 import time
-import importlib_resources
+from contextlib import ExitStack
+from os import environ, path
+from tempfile import mkdtemp
+from typing import Any, Dict, Optional
 
+import importlib_resources
 import six
 import yaml
 
-from contextlib import ExitStack
-from tempfile import mkdtemp
-import platform
-
-from typing import Any, Dict
-
 logging.basicConfig()
 logger = logging.getLogger(__name__)
 
@@ -60,9 +59,7 @@ PROFILES: Dict[str, Any] = CAPABILITIES["profiles"]
 
 
 class NotSupported(Exception):
-    """Raised if a requested feature is not supported by the
+    """Raised if a requested feature is not supported by the printer profile."""
-    printer profile.
-    """
 
     pass
 
@@ -80,11 +77,13 @@ class BaseProfile(object):
     profile_data: Dict[str, Any] = {}
 
     def __getattr__(self, name):
+        """Get a data element from the profile."""
         return self.profile_data[name]
 
     def get_font(self, font) -> int:
-        """Return the escpos index for `font`. Makes sure that
+        """Return the escpos index for `font`.
-        the requested `font` is valid.
+
+        Makes sure that the requested `font` is valid.
         """
         font = {"a": 0, "b": 1}.get(font, font)
         if not six.text_type(font) in self.fonts:
@@ -107,9 +106,10 @@ class BaseProfile(object):
         return {v: k for k, v in self.codePages.items()}
 
 
-def get_profile(name: str = None, **kwargs):
+def get_profile(name: Optional[str] = None, **kwargs):
-    """Get the profile by name; if no name is given, return the
+    """Get a profile by name.
-    default profile.
+
+    If no name is given, return the default profile.
     """
     if isinstance(name, Profile):
         return name
@@ -122,7 +122,9 @@ CLASS_CACHE = {}
 
 
 def get_profile_class(name: str):
-    """For the given profile name, load the data from the external
+    """Load a profile class.
+
+    For the given profile name, load the data from the external
     database, then generate dynamically a class.
     """
     if name not in CLASS_CACHE:
@@ -136,6 +138,7 @@ def get_profile_class(name: str):
 
 
 def clean(s):
+    """Clean profile name."""
     # Remove invalid characters
     s = re.sub("[^0-9a-zA-Z_]", "", s)
     # Remove leading characters until we find a letter or underscore
@@ -144,17 +147,20 @@ def clean(s):
 
 
 class Profile(get_profile_class("default")):
-    """
+    """Profile class for user usage.
-    For users, who want to provide their profile
+
+    For users, who want to provide their own profile.
     """
 
     def __init__(self, columns=None, features=None):
+        """Initialize profile."""
         super(Profile, self).__init__()
 
         self.columns = columns
         self.features = features or {}
 
     def get_columns(self, font):
+        """Get column count of printer."""
         if self.columns is not None:
             return self.columns
 

src/escpos/cli.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 # PYTHON_ARGCOMPLETE_OK
-""" CLI
+"""CLI.
 
 This module acts as a command line interface for python-escpos. It mirrors
 closely the available ESCPOS commands while adding a couple extra ones for convenience.
@@ -18,15 +18,18 @@ except ImportError:
     # this CLI works nevertheless without argcomplete
     pass  # noqa
 import sys
+
 import six
-from . import config
+
-from . import version
+from . import config, version
 
 
 # Must be defined before it's used in DEMO_FUNCTIONS
 def str_to_bool(string):
-    """Used as a type in argparse so that we get back a proper
+    """Convert string to Bool.
-    bool instead of always True
+
+    Used as a type in argparse so that we get back a proper
+    bool instead of always True.
     """
     return string.lower() in ("y", "yes", "1", "true")
 
@@ -452,13 +455,11 @@ ESCPOS_COMMANDS = [
 
 
 def main():
-    """
+    """Handle main entry point of CLI script.
 
     Handles loading of configuration and creating and processing of command
     line arguments. Called when run from a CLI.
-
     """
-
     parser = argparse.ArgumentParser(
         description="CLI for python-escpos",
         epilog="Printer configuration is defined in the python-escpos config"
@@ -569,8 +570,9 @@ def main():
 
 
 def demo(printer, **kwargs):
-    """
+    """Print demos.
-    Prints demos. Called when CLI is passed `demo`. This function
+
+    Called when CLI is passed `demo`. This function
     uses the DEMO_FUNCTIONS dictionary.
 
     :param printer: A printer from escpos.printer

src/escpos/codepages.py

@@ -1,23 +1,31 @@
+"""Helper module for codepage handling."""
 from .capabilities import CAPABILITIES
 
 
 class CodePageManager:
-    """Holds information about all the code pages (as defined
+    """Holds information about all the code pages.
-    in escpos-printer-db).
+
+    Information as defined in escpos-printer-db.
     """
 
     def __init__(self, data):
+        """Initialize codepage manager."""
         self.data = data
 
     def get_all(self):
+        """Get list of all codepages."""
         return self.data.values()
 
     @staticmethod
     def get_encoding_name(encoding):
-        # TODO resolve the encoding alias
+        """Get encoding name.
+
+        .. todo:: Resolve the encoding alias.
+        """
         return encoding.upper()
 
     def get_encoding(self, encoding):
+        """Return the encoding data."""
         return self.data[encoding]
 
 

src/escpos/config.py

@@ -1,16 +1,13 @@
 """ESC/POS configuration manager.
 
 This module contains the implementations of abstract base class :py:class:`Config`.
-
 """
-
-
 import os
+
 import appdirs
 import yaml
 
-from . import printer
+from . import exceptions, printer
-from . import exceptions
 
 
 class Config(object):
@@ -48,13 +45,11 @@ class Config(object):
         self._printer_config = None
 
     def load(self, config_path=None):
-        """Load and parse the configuration file using pyyaml
+        """Load and parse the configuration file using pyyaml.
 
         :param config_path: An optional file path, file handle, or byte string
             for the configuration file.
-
         """
-
         self._reset_config()
 
         if not config_path:
@@ -96,8 +91,9 @@ class Config(object):
         self._has_loaded = True
 
     def printer(self):
-        """Returns a printer that was defined in the config, or throws an
+        """Return a printer that was defined in the config.
-        exception.
+
+        Throw an exception on error.
 
         This method loads the default config if one hasn't beeen already loaded.
 

src/escpos/escpos.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python
 #  -*- coding: utf-8 -*-
-""" Main class
+"""Main class.
 
 This module contains the abstract base class :py:class:`Escpos`.
 
@@ -11,80 +11,88 @@ This module contains the abstract base class :py:class:`Escpos`.
 """
 
 
-import qrcode
 import textwrap
-import six
+from abc import ABCMeta, abstractmethod  # abstract base class support
 from re import match as re_match
+from typing import Union
 
 import barcode
+import qrcode
+import six
 from barcode.writer import ImageWriter
 
+from escpos.capabilities import get_profile
+from escpos.image import EscposImage
+
 from .constants import (
-    ESC,
+    BARCODE_FONT_A,
-    GS,
+    BARCODE_FONT_B,
-    NUL,
+    BARCODE_FORMATS,
-    QR_ECLEVEL_L,
-    QR_ECLEVEL_M,
-    QR_ECLEVEL_H,
-    QR_ECLEVEL_Q,
-    SHEET_ROLL_MODE,
-    SHEET_SLIP_MODE,
-    SLIP_PRINT_AND_EJECT,
-    SLIP_SELECT,
-    SLIP_EJECT,
-)
-from .constants import (
-    QR_MODEL_1,
-    QR_MODEL_2,
-    QR_MICRO,
-    BARCODE_TYPES,
     BARCODE_HEIGHT,
-    BARCODE_WIDTH,
-)
-from .constants import BARCODE_FONT_A, BARCODE_FONT_B, BARCODE_FORMATS
-from .constants import (
-    BARCODE_TXT_OFF,
-    BARCODE_TXT_BTH,
     BARCODE_TXT_ABV,
     BARCODE_TXT_BLW,
-)
+    BARCODE_TXT_BTH,
-from .constants import TXT_SIZE, TXT_NORMAL
+    BARCODE_TXT_OFF,
-from .constants import SET_FONT
+    BARCODE_TYPES,
-from .constants import LINESPACING_FUNCS, LINESPACING_RESET
+    BARCODE_WIDTH,
-from .constants import LINE_DISPLAY_OPEN, LINE_DISPLAY_CLEAR, LINE_DISPLAY_CLOSE
-from .constants import (
-    CD_KICK_DEC_SEQUENCE,
-    CD_KICK_5,
-    CD_KICK_2,
-    PAPER_FULL_CUT,
-    PAPER_PART_CUT,
     BUZZER,
-)
+    CD_KICK_2,
-from .constants import HW_RESET, HW_SELECT, HW_INIT
+    CD_KICK_5,
-from .constants import (
+    CD_KICK_DEC_SEQUENCE,
-    CTL_VT,
     CTL_CR,
     CTL_FF,
     CTL_LF,
     CTL_SET_HT,
+    CTL_VT,
+    ESC,
+    GS,
+    HW_INIT,
+    HW_RESET,
+    HW_SELECT,
+    LINE_DISPLAY_CLEAR,
+    LINE_DISPLAY_CLOSE,
+    LINE_DISPLAY_OPEN,
+    LINESPACING_FUNCS,
+    LINESPACING_RESET,
+    NUL,
     PANEL_BUTTON_OFF,
     PANEL_BUTTON_ON,
+    PAPER_FULL_CUT,
+    PAPER_PART_CUT,
+    QR_ECLEVEL_H,
+    QR_ECLEVEL_L,
+    QR_ECLEVEL_M,
+    QR_ECLEVEL_Q,
+    QR_MICRO,
+    QR_MODEL_1,
+    QR_MODEL_2,
+    RT_MASK_LOWPAPER,
+    RT_MASK_NOPAPER,
+    RT_MASK_ONLINE,
+    RT_MASK_PAPER,
+    RT_STATUS_ONLINE,
+    RT_STATUS_PAPER,
+    SET_FONT,
+    SHEET_ROLL_MODE,
+    SHEET_SLIP_MODE,
+    SLIP_EJECT,
+    SLIP_PRINT_AND_EJECT,
+    SLIP_SELECT,
+    TXT_NORMAL,
+    TXT_SIZE,
+    TXT_STYLE,
+)
+from .exceptions import (
+    BarcodeCodeError,
+    BarcodeSizeError,
+    BarcodeTypeError,
+    CashDrawerError,
+    ImageWidthError,
+    SetVariableError,
+    TabPosError,
 )
-from .constants import TXT_STYLE
-from .constants import RT_STATUS_ONLINE, RT_MASK_ONLINE
-from .constants import RT_STATUS_PAPER, RT_MASK_PAPER, RT_MASK_LOWPAPER, RT_MASK_NOPAPER
-
-from .exceptions import BarcodeTypeError, BarcodeSizeError, TabPosError
-from .exceptions import CashDrawerError, SetVariableError, BarcodeCodeError
-from .exceptions import ImageWidthError
-
 from .magicencode import MagicEncode
 
-from abc import ABCMeta, abstractmethod  # abstract base class support
-from escpos.image import EscposImage
-from escpos.capabilities import get_profile
-
-
 # Remove special characters and whitespaces of the supported barcode names,
 # convert to uppercase and map them to their original names.
 HW_BARCODE_NAMES = {
@@ -100,7 +108,7 @@ SW_BARCODE_NAMES = {
 
 @six.add_metaclass(ABCMeta)
 class Escpos(object):
-    """ESC/POS Printer object
+    """ESC/POS Printer object.
 
     This class is the abstract base class for an esc/pos-printer. The printer implementations are children of this
     class.
@@ -109,19 +117,20 @@ class Escpos(object):
     device = None
 
     def __init__(self, profile=None, magic_encode_args=None, **kwargs):
-        """Initialize ESCPOS Printer
+        """Initialize ESCPOS Printer.
 
-        :param profile: Printer profile"""
+        :param profile: Printer profile
+        """
         self.profile = get_profile(profile)
         self.magic = MagicEncode(self, **(magic_encode_args or {}))
 
     def __del__(self):
-        """call self.close upon deletion"""
+        """Call self.close upon deletion."""
         self.close()
 
     @abstractmethod
-    def _raw(self, msg):
+    def _raw(self, msg: bytes):
-        """Sends raw data to the printer
+        """Send raw data to the printer.
 
         This function has to be individually implemented by the implementations.
 
@@ -131,7 +140,9 @@ class Escpos(object):
         pass
 
     def _read(self):
-        """Returns a NotImplementedError if the instance of the class doesn't override this method.
+        """Read from printer.
+
+        Returns a NotImplementedError if the instance of the class doesn't override this method.
         :raises NotImplementedError
         """
         raise NotImplementedError()
@@ -145,7 +156,7 @@ class Escpos(object):
         fragment_height=960,
         center=False,
     ):
-        """Print an image
+        """Print an image.
 
         You can select whether the printer should print in high density or not. The default value is high density.
         When printing in low density, the image will be stretched.
@@ -252,8 +263,7 @@ class Escpos(object):
             self._raw(b"".join(outp))
 
     def _image_send_graphics_data(self, m, fn, data):
-        """
+        """Calculate and send correct data length for `GS ( L`.
-        Wrapper for GS ( L, to calculate and send correct data length.
 
         :param m: Modifier//variant for function. Usually '0'
         :param fn: Function number to use, as byte
@@ -272,7 +282,7 @@ class Escpos(object):
         center=False,
         impl="bitImageRaster",
     ):
-        """Print QR Code for the provided string
+        """Print QR Code for the provided string.
 
         :param content: The content of the code. Numeric data will be more efficiently compacted.
         :param ec: Error-correction level to use. One of QR_ECLEVEL_L (default), QR_ECLEVEL_M, QR_ECLEVEL_Q or
@@ -345,7 +355,7 @@ class Escpos(object):
         self._send_2d_code_data(six.int2byte(81), cn, b"", b"0")
 
     def _send_2d_code_data(self, fn, cn, data, m=b""):
-        """Wrapper for GS ( k, to calculate and send correct data length.
+        """Calculate and send correct data length for`GS ( k`.
 
         :param fn: Function to use.
         :param cn: Output code type. Affects available data.
@@ -379,8 +389,8 @@ class Escpos(object):
             inp_number //= 256
         return outp
 
-    def charcode(self, code="AUTO"):
+    def charcode(self, code: str = "AUTO"):
-        """Set Character Code Table
+        """Set Character Code Table.
 
         Sets the control sequence from ``CHARCODE`` in :py:mod:`escpos.constants` as active. It will be sent with
         the next text sequence. If you set the variable code to ``AUTO`` it will try to automatically guess the
@@ -396,7 +406,8 @@ class Escpos(object):
 
     @staticmethod
     def check_barcode(bc, code):
-        """
+        """Check if barcode is OK.
+
         This method checks if the barcode is in the proper format.
         The validation concerns the barcode length and the set of characters, but won't compute/validate any checksum.
         The full set of requirement for each barcode type is available in the ESC/POS documentation.
@@ -444,15 +455,15 @@ class Escpos(object):
         self,
         code,
         bc,
-        height=64,
+        height: int = 64,
-        width=3,
+        width: int = 3,
-        pos="BELOW",
+        pos: str = "BELOW",
-        font="A",
+        font: str = "A",
-        align_ct=True,
+        align_ct: bool = True,
         function_type=None,
-        check=True,
+        check: bool = True,
-        force_software=False,
+        force_software: Union[bool, str] = False,
-    ):
+    ) -> None:
         """Print barcode.
 
         Automatic hardware|software barcode renderer according to the printer capabilities.
@@ -535,9 +546,11 @@ class Escpos(object):
             raise BarcodeTypeError(f"Not supported or wrong barcode name {bc}.")
 
         if force_software or not capable["hw"] or not capable_bc["hw"]:
+            # based on earlier checks, we require that software mode is not None
+            assert capable["sw"] is not None
             # Select the best possible capable render mode
             impl = capable["sw"][0]
-            if force_software in capable["sw"]:
+            if force_software in capable["sw"] and isinstance(force_software, str):
                 # Force to a specific mode
                 impl = force_software
             print(f"Using {impl} software barcode renderer")
@@ -567,15 +580,15 @@ class Escpos(object):
         self,
         code,
         bc,
-        height=64,
+        height: int = 64,
-        width=3,
+        width: int = 3,
-        pos="BELOW",
+        pos: str = "BELOW",
-        font="A",
+        font: str = "A",
-        align_ct=True,
+        align_ct: bool = True,
         function_type=None,
-        check=True,
+        check: bool = True,
     ):
-        """Print Barcode
+        """Print Barcode.
 
         This method allows to print barcodes. The rendering of the barcode is done by the printer and therefore has to
         be supported by the unit. By default, this method will check whether your barcode text is correct, that is
@@ -726,14 +739,14 @@ class Escpos(object):
         self,
         barcode_type,
         data,
-        impl="bitImageColumn",
+        impl: str = "bitImageColumn",
-        module_height=5,
+        module_height: Union[int, float] = 5,
-        module_width=0.2,
+        module_width: Union[int, float] = 0.2,
-        text_distance=5,
+        text_distance: Union[int, float] = 5,
-        font_size=10,
+        font_size: int = 10,
-        center=True,
+        center: bool = True,
     ):
-        """Print Barcode
+        """Print Barcode.
 
         This method allows to print barcodes. The rendering of the barcode is done by
         the `barcode` library and sent to the printer as image through one of the
@@ -773,13 +786,13 @@ class Escpos(object):
             * bitImageRaster
 
         :param module_height: barcode module height (in mm).
-        :type module_height: int | float
+        :type module_height: Union[int, float]
 
         :param module_width: barcode module width (in mm).
-        :type module_width: int | float
+        :type module_width: Union[int, float]
 
         :param text_distance: distance from the barcode to the code text (in mm).
-        :type text_distance: int | float
+        :type text_distance: Union[int, float]
 
         :param font_size: font size of the code text (in dots).
         :type font_size: int
@@ -817,7 +830,7 @@ class Escpos(object):
         self.image(image, impl=impl, center=center)
 
     def text(self, txt):
-        """Print alpha-numeric text
+        """Print alpha-numeric text.
 
         The text has to be encoded in the currently selected codepage.
         The input text has to be encoded in unicode.
@@ -829,7 +842,7 @@ class Escpos(object):
         self.magic.write(txt)
 
     def textln(self, txt=""):
-        """Print alpha-numeric text with a newline
+        """Print alpha-numeric text with a newline.
 
         The text has to be encoded in the currently selected codepage.
         The input text has to be encoded in unicode.
@@ -840,7 +853,7 @@ class Escpos(object):
         self.text("{}\n".format(txt))
 
     def ln(self, count=1):
-        """Print a newline or more
+        """Print a newline or more.
 
         :param count: number of newlines to print
         :raises: :py:exc:`ValueError` if count < 0
@@ -851,7 +864,7 @@ class Escpos(object):
             self.text("\n" * count)
 
     def block_text(self, txt, font="0", columns=None):
-        """Text is printed wrapped to specified columns
+        """Print text wrapped to specifiec columns.
 
         Text has to be encoded in unicode.
 
@@ -879,7 +892,7 @@ class Escpos(object):
         double_height=False,
         custom_size=False,
     ):
-        """Set text properties by sending them to the printer
+        """Set text properties by sending them to the printer.
 
         :param align: horizontal position for text, possible values are:
 
@@ -918,7 +931,6 @@ class Escpos(object):
         :type height: int
         :type density: int
         """
-
         if custom_size:
             if (
                 1 <= width <= 8
@@ -996,7 +1008,6 @@ class Escpos(object):
         :param feed: print and feed before cutting. default: true
         :raises ValueError: if mode not in ('FULL', 'PART')
         """
-
         if not feed:
             self._raw(GS + b"V" + six.int2byte(66) + b"\x00")
             return
@@ -1019,7 +1030,7 @@ class Escpos(object):
                 self._raw(PAPER_PART_CUT)
 
     def cashdraw(self, pin):
-        """Send pulse to kick the cash drawer
+        """Send pulse to kick the cash drawer.
 
         Kick cash drawer on pin 2 (:py:const:`~escpos.constants.CD_KICK_2`)
         or pin 5 (:py:const:`~escpos.constants.CD_KICK_5`)
@@ -1041,7 +1052,7 @@ class Escpos(object):
                 raise CashDrawerError(err)
 
     def linedisplay_select(self, select_display=False):
-        """Selects the line display or the printer
+        """Select the line display or the printer.
 
         This method is used for line displays that are daisy-chained between your computer and printer.
         If you set `select_display` to true, only the display is selected and if you set it to false,
@@ -1056,15 +1067,14 @@ class Escpos(object):
             self._raw(LINE_DISPLAY_CLOSE)
 
     def linedisplay_clear(self):
-        """Clears the line display and resets the cursor
+        """Clear the line display and resets the .
 
         This method is used for line displays that are daisy-chained between your computer and printer.
         """
         self._raw(LINE_DISPLAY_CLEAR)
 
     def linedisplay(self, text):
-        """
+        """Display text on a line display connected to your printer.
-        Display text on a line display connected to your printer
 
         You should connect a line display to your printer. You can do this by daisy-chaining
         the display between your computer and printer.
@@ -1077,7 +1087,7 @@ class Escpos(object):
         self.linedisplay_select(select_display=False)
 
     def hw(self, hw):
-        """Hardware operations
+        """Hardware operations.
 
         :param hw: hardware action, may be:
 
@@ -1095,7 +1105,7 @@ class Escpos(object):
             pass
 
     def print_and_feed(self, n=1):
-        """Print data in print buffer and feed *n* lines
+        """Print data in print buffer and feed *n* lines.
 
         If n not in range (0, 255) then a ValueError will be raised.
 
@@ -1109,7 +1119,7 @@ class Escpos(object):
             raise ValueError("n must be betwen 0 and 255")
 
     def control(self, ctl, count=5, tab_size=8):
-        """Feed control sequences
+        """Feed control sequences.
 
         :param ctl: string for the following control sequences:
 
@@ -1145,7 +1155,7 @@ class Escpos(object):
             self._raw(CTL_VT)
 
     def panel_buttons(self, enable=True):
-        """Controls the panel buttons on the printer (e.g. FEED)
+        """Control the panel buttons on the printer (e.g. FEED).
 
         When enable is set to False the panel buttons on the printer
         will be disabled.
@@ -1175,9 +1185,9 @@ class Escpos(object):
             self._raw(PANEL_BUTTON_OFF)
 
     def query_status(self, mode):
-        """
+        """Query the printer for its status.
-        Queries the printer for its status, and returns an array
+
-        of integers containing it.
+        Returns an array of integers containing it.
 
         :param mode: Integer that sets the status mode queried to the printer.
             - RT_STATUS_ONLINE: Printer status.
@@ -1189,8 +1199,7 @@ class Escpos(object):
         return status
 
     def is_online(self):
-        """
+        """Query the online status of the printer.
-        Queries the online status of the printer.
 
         :returns: When online, returns ``True``; ``False`` otherwise.
         :rtype: bool
@@ -1201,8 +1210,7 @@ class Escpos(object):
         return not (status[0] & RT_MASK_ONLINE)
 
     def paper_status(self):
-        """
+        """Query the paper status of the printer.
-        Queries the paper status of the printer.
 
         Returns 2 if there is plenty of paper, 1 if the paper has arrived to
         the near-end sensor and 0 if there is no paper.
@@ -1221,7 +1229,7 @@ class Escpos(object):
             return 2
 
     def target(self, type="ROLL"):
-        """Select where to print to
+        """Select where to print to.
 
         Print to the thermal printer by default (ROLL) or
         print to the slip dot matrix printer if supported (SLIP)
@@ -1234,11 +1242,11 @@ class Escpos(object):
             raise ValueError("Unsupported target")
 
     def eject_slip(self):
-        """Eject the slip/cheque"""
+        """Eject the slip/cheque."""
         self._raw(SLIP_EJECT)
 
     def print_and_eject_slip(self):
-        """Print and eject
+        """Print and eject.
 
         Prints data from the buffer to the slip station and if the paper
         sensor is covered, reverses the slip out the front of the printer
@@ -1248,7 +1256,7 @@ class Escpos(object):
         self._raw(SLIP_PRINT_AND_EJECT)
 
     def use_slip_only(self):
-        """Selects the Slip Station for all functions.
+        """Select the Slip Station for all functions.
 
         The receipt station is the default setting after the printer
         is initialized or the Clear Printer (0x10) command is received
@@ -1256,7 +1264,7 @@ class Escpos(object):
         self._raw(SLIP_SELECT)
 
     def buzzer(self, times=2, duration=4):
-        """Activate the internal printer buzzer (only supported printers).
+        """Activate the internal printer buzzer on supported printers.
 
         The 'times' parameter refers to the 'n' escpos command parameter,
         which means how many times the buzzer will be 'beeped'.
@@ -1265,7 +1273,6 @@ class Escpos(object):
         :param duration: Integer between 1 and 9, indicates the beep duration.
         :returns: None
         """
-
         if not 1 <= times <= 9:
             raise ValueError("times must be between 1 and 9")
         if not 1 <= duration <= 9:
@@ -1275,7 +1282,7 @@ class Escpos(object):
 
 
 class EscposIO(object):
-    """ESC/POS Printer IO object
+    r"""ESC/POS Printer IO object.
 
     Allows the class to be used together with the `with`-statement. You have to define a printer instance
     and assign it to the EscposIO class.
@@ -1295,7 +1302,8 @@ class EscposIO(object):
     """
 
     def __init__(self, printer, autocut=True, autoclose=True, **kwargs):
-        """
+        """Initialize object.
+
         :param printer: An EscPos-printer object
         :type printer: escpos.Escpos
         :param autocut: If True, paper is automatically cut after the `with`-statement *default*: True
@@ -1307,7 +1315,7 @@ class EscposIO(object):
         self.autoclose = autoclose
 
     def set(self, **kwargs):
-        """Set the printer-parameters
+        """Set the printer-parameters.
 
         Controls which parameters will be passed to :py:meth:`Escpos.set() <escpos.escpos.Escpos.set()>`.
         For more information on the parameters see the :py:meth:`set() <escpos.escpos.Escpos.set()>`-methods
@@ -1319,6 +1327,7 @@ class EscposIO(object):
         self.params.update(kwargs)
 
     def writelines(self, text, **kwargs):
+        """Print text."""
         params = dict(self.params)
         params.update(kwargs)
 
@@ -1341,14 +1350,18 @@ class EscposIO(object):
                 self.printer.text("{0}\n".format(line))
 
     def close(self):
-        """called upon closing the `with`-statement"""
+        """Close printer.
+
+        Called upon closing the `with`-statement.
+        """
         self.printer.close()
 
     def __enter__(self, **kwargs):
+        """Enter context."""
         return self
 
     def __exit__(self, type, value, traceback):
-        """
+        """Cut and close if configured.
 
         If :py:attr:`autocut <escpos.escpos.EscposIO.autocut>` is `True` (set by this class' constructor),
         then :py:meth:`printer.cut() <escpos.escpos.Escpos.cut()>` will be called here.

src/escpos/exceptions.py

@@ -1,5 +1,5 @@
 #  -*- coding: utf-8 -*-
-""" ESC/POS Exceptions classes
+"""ESC/POS Exceptions classes.
 
 Result/Exit codes:
 
@@ -27,9 +27,10 @@ Result/Exit codes:
 
 
 class Error(Exception):
-    """Base class for ESC/POS errors"""
+    """Base class for ESC/POS errors."""
 
     def __init__(self, msg, status=None):
+        """Initialize Error object."""
         Exception.__init__(self)
         self.msg = msg
         self.resultcode = 1
@@ -37,6 +38,7 @@ class Error(Exception):
             self.resultcode = status
 
     def __str__(self):
+        """Return string representation of Error."""
         return self.msg
 
 
@@ -49,11 +51,13 @@ class BarcodeTypeError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize BarcodeTypeError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 10
 
     def __str__(self):
+        """Return string representation of BarcodeTypeError."""
         return "No Barcode type is defined ({msg})".format(msg=self.msg)
 
 
@@ -66,11 +70,13 @@ class BarcodeSizeError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize BarcodeSizeError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 20
 
     def __str__(self):
+        """Return string representation of BarcodeSizeError."""
         return "Barcode size is out of range ({msg})".format(msg=self.msg)
 
 
@@ -83,11 +89,13 @@ class BarcodeCodeError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize BarcodeCodeError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 30
 
     def __str__(self):
+        """Return string representation of BarcodeCodeError."""
         return "No Barcode code was supplied ({msg})".format(msg=self.msg)
 
 
@@ -98,11 +106,13 @@ class ImageSizeError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize ImageSizeError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 40
 
     def __str__(self):
+        """Return string representation of ImageSizeError."""
         return "Image height is longer than 255px and can't be printed ({msg})".format(
             msg=self.msg
         )
@@ -115,11 +125,13 @@ class ImageWidthError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize ImageWidthError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 41
 
     def __str__(self):
+        """Return string representation of ImageWidthError."""
         return "Image width is too large ({msg})".format(msg=self.msg)
 
 
@@ -131,11 +143,13 @@ class TextError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize TextError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 50
 
     def __str__(self):
+        """Return string representation of TextError."""
         return "Text string must be supplied to the text() method ({msg})".format(
             msg=self.msg
         )
@@ -149,16 +163,20 @@ class CashDrawerError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize CashDrawerError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 60
 
     def __str__(self):
+        """Return string representation of CashDrawerError."""
         return "Valid pin must be set to send pulse ({msg})".format(msg=self.msg)
 
 
 class TabPosError(Error):
-    """Valid tab positions must be set by using from 1 to 32 tabs, and between 1 and 255 tab size values.
+    """Tab position is invalid.
+
+    Valid tab positions must be set by using from 1 to 32 tabs, and between 1 and 255 tab size values.
     Both values multiplied must not exceed 255, since it is the maximum tab value.
 
     This exception is raised by :py:meth:`escpos.escpos.Escpos.control`.
@@ -166,11 +184,13 @@ class TabPosError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize TabPosError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 70
 
     def __str__(self):
+        """Return string representation of TabPosError."""
         return "Valid tab positions must be in the range 0 to 16 ({msg})".format(
             msg=self.msg
         )
@@ -184,43 +204,49 @@ class CharCodeError(Error):
     """
 
     def __init__(self, msg=""):
+        """Initialize CharCodeError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 80
 
     def __str__(self):
+        """Return string representation of CharCodeError."""
         return "Valid char code must be set ({msg})".format(msg=self.msg)
 
 
 class USBNotFoundError(Error):
-    """Device wasn't found (probably not plugged in)
+    """Device wasn't found (probably not plugged in).
 
     The USB device seems to be not plugged in.
     Ths returncode for this exception is `90`.
     """
 
     def __init__(self, msg=""):
+        """Initialize USBNotFoundError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 90
 
     def __str__(self):
+        """Return string representation of USBNotFoundError."""
         return "USB device not found ({msg})".format(msg=self.msg)
 
 
 class SetVariableError(Error):
-    """A set method variable was out of range
+    """A set method variable was out of range.
 
     Check set variables against minimum and maximum values
     Ths returncode for this exception is `100`.
     """
 
     def __init__(self, msg=""):
+        """Initialize SetVariableError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 100
 
     def __str__(self):
+        """Return string representation of SetVariableError."""
         return "Set variable out of range ({msg})".format(msg=self.msg)
 
 
@@ -228,48 +254,54 @@ class SetVariableError(Error):
 
 
 class ConfigNotFoundError(Error):
-    """The configuration file was not found
+    """The configuration file was not found.
 
     The default or passed configuration file could not be read
     Ths returncode for this exception is `200`.
     """
 
     def __init__(self, msg=""):
+        """Initialize ConfigNotFoundError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 200
 
     def __str__(self):
+        """Return string representation of ConfigNotFoundError."""
         return "Configuration not found ({msg})".format(msg=self.msg)
 
 
 class ConfigSyntaxError(Error):
-    """The configuration file is invalid
+    """The configuration file is invalid.
 
     The syntax is incorrect
     Ths returncode for this exception is `210`.
     """
 
     def __init__(self, msg=""):
+        """Initialize ConfigSyntaxError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 210
 
     def __str__(self):
+        """Return string representation of ConfigSyntaxError."""
         return "Configuration syntax is invalid ({msg})".format(msg=self.msg)
 
 
 class ConfigSectionMissingError(Error):
-    """The configuration file is missing a section
+    """The configuration file is missing a section.
 
     The part of the config asked for doesn't exist in the loaded configuration
     Ths returncode for this exception is `220`.
     """
 
     def __init__(self, msg=""):
+        """Initialize ConfigSectionMissingError object."""
         Error.__init__(self, msg)
         self.msg = msg
         self.resultcode = 220
 
     def __str__(self):
+        """Return string representation of ConfigSectionMissingError."""
         return "Configuration section is missing ({msg})".format(msg=self.msg)

src/escpos/image.py

@@ -1,4 +1,4 @@
-""" Image format handling class
+"""Image format handling class.
 
 This module contains the image format handler :py:class:`EscposImage`.
 
@@ -10,6 +10,7 @@ This module contains the image format handler :py:class:`EscposImage`.
 
 
 import math
+
 from PIL import Image, ImageOps
 
 
@@ -22,8 +23,7 @@ class EscposImage(object):
     """
 
     def __init__(self, img_source):
-        """
+        """Load in an image.
-        Load in an image
 
         :param img_source: PIL.Image, or filename to load one from.
         """
@@ -49,30 +49,23 @@ class EscposImage(object):
 
     @property
     def width(self):
-        """
+        """Return width of image in pixels."""
-        Width of image in pixels
-        """
         width_pixels, _ = self._im.size
         return width_pixels
 
     @property
     def width_bytes(self):
-        """
+        """Return width of image if you use 8 pixels per byte and 0-pad at the end."""
-        Width of image if you use 8 pixels per byte and 0-pad at the end.
-        """
         return (self.width + 7) >> 3
 
     @property
     def height(self):
-        """
+        """Height of image in pixels."""
-        Height of image in pixels
-        """
         _, height_pixels = self._im.size
         return height_pixels
 
     def to_column_format(self, high_density_vertical=True):
-        """
+        """Extract slices of an image as equal-sized blobs of column-format data.
-        Extract slices of an image as equal-sized blobs of column-format data.
 
         :param high_density_vertical: Printed line height in dots
         """
@@ -89,14 +82,11 @@ class EscposImage(object):
             left += line_height
 
     def to_raster_format(self):
-        """
+        """Convert image to raster-format binary."""
-        Convert image to raster-format binary
-        """
         return self._im.tobytes()
 
     def split(self, fragment_height):
-        """
+        """Split an image into multiple fragments after fragment_height pixels.
-        Split an image into multiple fragments after fragment_height pixels
 
         :param fragment_height: height of fragment
         :return: list of PIL objects
@@ -113,7 +103,7 @@ class EscposImage(object):
         return fragments
 
     def center(self, max_width):
-        """In-place image centering
+        """Center image in place.
 
         :param: Maximum width in order to deduce x offset for centering
         :return: None

src/escpos/magicencode.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python
 #  -*- coding: utf-8 -*-
-""" Magic Encode
+"""Magic Encode.
 
 This module tries to convert an UTF-8 string to an encoded string for the printer.
 It uses trial and error in order to guess the right codepage.
@@ -13,17 +13,18 @@ The code is based on the encoding-code in py-xml-escpos by @fvdsn.
 """
 
 
+import re
 from builtins import bytes
+
+import six
+
+from .codepages import CodePages
 from .constants import CODEPAGE_CHANGE
 from .exceptions import Error
-from .codepages import CodePages
-import six
-import re
 
 
 class Encoder(object):
-    """Takes a list of available code spaces. Picks the right one for a
+    """Take available code spaces and pick the right one for a given character.
-    given character.
 
     Note: To determine the code page, it needs to do the conversion, and
     thus already knows what the final byte in the target encoding would
@@ -39,20 +40,24 @@ class Encoder(object):
     """
 
     def __init__(self, codepage_map):
+        """Initialize encoder."""
         self.codepages = codepage_map
         self.available_encodings = set(codepage_map.keys())
         self.available_characters = {}
         self.used_encodings = set()
 
     def get_sequence(self, encoding):
+        """Get a sequence."""
         return int(self.codepages[encoding])
 
     def get_encoding_name(self, encoding):
-        """Given an encoding provided by the user, will return a
+        """Return a canonical encoding name.
+
+        Given an encoding provided by the user, will return a
         canonical encoding name; and also validate that the encoding
         is supported.
 
-        TODO: Support encoding aliases: pc437 instead of cp437.
+        .. todo:: Support encoding aliases: pc437 instead of cp437.
         """
         encoding = CodePages.get_encoding_name(encoding)
         if encoding not in self.codepages:
@@ -66,7 +71,7 @@ class Encoder(object):
 
     @staticmethod
     def _get_codepage_char_list(encoding):
-        """Get codepage character list
+        """Get codepage character list.
 
         Gets characters 128-255 for a given code page, as an array.
 
@@ -92,7 +97,7 @@ class Encoder(object):
         raise LookupError("Can't find a known encoding for {}".format(encoding))
 
     def _get_codepage_char_map(self, encoding):
-        """Get codepage character map
+        """Get codepage character map.
 
         Process an encoding and return a map of UTF-characters to code points
         in this encoding.
@@ -130,7 +135,7 @@ class Encoder(object):
 
     @staticmethod
     def _encode_char(char, charmap, defaultchar):
-        """Encode a single character with the given encoding map
+        """Encode a single character with the given encoding map.
 
         :param char: char to encode
         :param charmap: dictionary for mapping characters in this code page
@@ -142,7 +147,7 @@ class Encoder(object):
         return ord(defaultchar)
 
     def encode(self, text, encoding, defaultchar="?"):
-        """Encode text under the given encoding
+        """Encode text under the given encoding.
 
         :param text: Text to encode
         :param encoding: Encoding name to use (must be defined in capabilities)
@@ -159,7 +164,9 @@ class Encoder(object):
         return (key in self.used_encodings, index)
 
     def find_suitable_encoding(self, char):
-        """The order of our search is a specific one:
+        """Search in a specific order for a suitable encoding.
+
+        It is the following order:
 
         1. code pages that we already tried before; there is a good
            chance they might work again, reducing the search space,
@@ -184,7 +191,9 @@ class Encoder(object):
 
 
 def split_writable_text(encoder, text, encoding):
-    """Splits off as many characters from the beginning of text as
+    """Split up the writable text.
+
+    Splits off as many characters from the beginning of text as
     are writable with "encoding". Returns a 2-tuple (writable, rest).
     """
     if not encoding:
@@ -199,7 +208,9 @@ def split_writable_text(encoder, text, encoding):
 
 
 class MagicEncode(object):
-    """A helper that helps us to automatically switch to the right
+    """Help switching to the right code page.
+
+    A helper that helps us to automatically switch to the right
     code page to encode any given Unicode character.
 
     This will consider the printers supported codepages, according
@@ -213,7 +224,7 @@ class MagicEncode(object):
     def __init__(
         self, driver, encoding=None, disabled=False, defaultsymbol="?", encoder=None
     ):
-        """
+        """Initialize magic encode.
 
         :param driver:
         :param encoding: If you know the current encoding of the printer
@@ -235,7 +246,7 @@ class MagicEncode(object):
         self.disabled = disabled
 
     def force_encoding(self, encoding):
-        """Sets a fixed encoding. The change is emitted right away.
+        """Set a fixed encoding. The change is emitted right away.
 
         From now one, this buffer will switch the code page anymore.
         However, it will still keep track of the current code page.
@@ -248,7 +259,6 @@ class MagicEncode(object):
 
     def write(self, text):
         """Write the text, automatically switching encodings."""
-
         if self.disabled:
             self.write_with_encoding(self.encoding, text)
             return
@@ -277,12 +287,16 @@ class MagicEncode(object):
                 self.write_with_encoding(encoding, to_write)
 
     def _handle_character_failed(self, char):
-        """Called when no codepage was found to render a character."""
+        """Write a default symbol.
+
+        Called when no codepage was found to render a character.
+        """
         # Writing the default symbol via write() allows us to avoid
         # unnecesary codepage switches.
         self.write(self.defaultsymbol)
 
     def write_with_encoding(self, encoding, text):
+        """Write the text and inject necessary codepage switches."""
         if text is not None and type(text) is not six.text_type:
             raise Error(
                 "The supplied text has to be unicode, but is of type {type}.".format(

src/escpos/printer.py

@@ -31,16 +31,17 @@ except ImportError:
 
 _CUPSPRINT = False
 try:
-    import cups
     import tempfile
 
+    import cups
+
     _CUPSPRINT = True
 except ImportError:
     pass
 
 
 class Usb(Escpos):
-    """USB printer
+    """USB printer.
 
     This class describes a printer that natively speaks USB.
 
@@ -62,7 +63,8 @@ class Usb(Escpos):
         *args,
         **kwargs
     ):  # noqa: N803
-        """
+        """Initialize USB printer.
+
         :param idVendor: Vendor ID
         :param idProduct: Product ID
         :param usb_args: Optional USB arguments (e.g. custom_match)
@@ -122,7 +124,7 @@ class Usb(Escpos):
             print("Could not set configuration: {0}".format(str(e)))
 
     def _raw(self, msg):
-        """Print any command sent in raw format
+        """Print any command sent in raw format.
 
         :param msg: arbitrary code to be printed
         :type msg: bytes
@@ -130,18 +132,18 @@ class Usb(Escpos):
         self.device.write(self.out_ep, msg, self.timeout)
 
     def _read(self):
-        """Reads a data buffer and returns it to the caller."""
+        """Read a data buffer and return it to the caller."""
         return self.device.read(self.in_ep, 16)
 
     def close(self):
-        """Release USB interface"""
+        """Release USB interface."""
         if self.device:
             usb.util.dispose_resources(self.device)
         self.device = None
 
 
 class Serial(Escpos):
-    """Serial printer
+    """Serial printer.
 
     This class describes a printer that is connected by serial interface.
 
@@ -165,7 +167,7 @@ class Serial(Escpos):
         *args,
         **kwargs
     ):
-        """
+        """Initialize serial printer.
 
         :param devfile:  Device file under dev filesystem
         :param baudrate: Baud rate for serial transmission
@@ -189,7 +191,7 @@ class Serial(Escpos):
         self.open()
 
     def open(self):
-        """Setup serial port and set is as escpos device"""
+        """Set up serial port and set is as escpos device."""
         if self.device is not None and self.device.is_open:
             self.close()
         self.device = serial.Serial(
@@ -209,7 +211,7 @@ class Serial(Escpos):
             print("Unable to open serial printer on: {0}".format(str(self.devfile)))
 
     def _raw(self, msg):
-        """Print any command sent in raw format
+        """Print any command sent in raw format.
 
         :param msg: arbitrary code to be printed
         :type msg: bytes
@@ -217,18 +219,18 @@ class Serial(Escpos):
         self.device.write(msg)
 
     def _read(self):
-        """Reads a data buffer and returns it to the caller."""
+        """Read the data buffer and return it to the caller."""
         return self.device.read(16)
 
     def close(self):
-        """Close Serial interface"""
+        """Close Serial interface."""
         if self.device is not None and self.device.is_open:
             self.device.flush()
             self.device.close()
 
 
 class Network(Escpos):
-    """Network printer
+    """Network printer.
 
     This class is used to attach to a networked printer. You can also use this in order to attach to a printer that
     is forwarded with ``socat``.
@@ -251,7 +253,7 @@ class Network(Escpos):
     """
 
     def __init__(self, host, port=9100, timeout=60, *args, **kwargs):
-        """
+        """Initialize network printer.
 
         :param host:    Printer's hostname or IP address
         :param port:    Port to write to
@@ -264,7 +266,7 @@ class Network(Escpos):
         self.open()
 
     def open(self):
-        """Open TCP socket with ``socket``-library and set it as escpos device"""
+        """Open TCP socket with ``socket``-library and set it as escpos device."""
         self.device = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self.device.settimeout(self.timeout)
         self.device.connect((self.host, self.port))
@@ -273,7 +275,7 @@ class Network(Escpos):
             print("Could not open socket for {0}".format(self.host))
 
     def _raw(self, msg):
-        """Print any command sent in raw format
+        """Print any command sent in raw format.
 
         :param msg: arbitrary code to be printed
         :type msg: bytes
@@ -281,12 +283,11 @@ class Network(Escpos):
         self.device.sendall(msg)
 
     def _read(self):
-        """Read data from the TCP socket"""
+        """Read data from the TCP socket."""
-
         return self.device.recv(16)
 
     def close(self):
-        """Close TCP connection"""
+        """Close TCP connection."""
         if self.device is not None:
             try:
                 self.device.shutdown(socket.SHUT_RDWR)
@@ -296,7 +297,7 @@ class Network(Escpos):
 
 
 class File(Escpos):
-    """Generic file printer
+    """Generic file printer.
 
     This class is used for parallel port printer or other printers that are directly attached to the filesystem.
     Note that you should stay away from using USB-to-Parallel-Adapter since they are unreliable
@@ -310,7 +311,7 @@ class File(Escpos):
     """
 
     def __init__(self, devfile="/dev/usb/lp0", auto_flush=True, *args, **kwargs):
-        """
+        """Initialize file printer with device file.
 
         :param devfile: Device file under dev filesystem
         :param auto_flush: automatically call flush after every call of _raw()
@@ -321,18 +322,18 @@ class File(Escpos):
         self.open()
 
     def open(self):
-        """Open system file"""
+        """Open system file."""
         self.device = open(self.devfile, "wb")
 
         if self.device is None:
             print("Could not open the specified file {0}".format(self.devfile))
 
     def flush(self):
-        """Flush printing content"""
+        """Flush printing content."""
         self.device.flush()
 
     def _raw(self, msg):
-        """Print any command sent in raw format
+        """Print any command sent in raw format.
 
         :param msg: arbitrary code to be printed
         :type msg: bytes
@@ -342,14 +343,14 @@ class File(Escpos):
             self.flush()
 
     def close(self):
-        """Close system file"""
+        """Close system file."""
         if self.device is not None:
             self.device.flush()
             self.device.close()
 
 
 class Dummy(Escpos):
-    """Dummy printer
+    """Dummy printer.
 
     This class is used for saving commands to a variable, for use in situations where
     there is no need to send commands to an actual printer. This includes
@@ -363,12 +364,12 @@ class Dummy(Escpos):
     """
 
     def __init__(self, *args, **kwargs):
-        """ """
+        """Init with empty output list."""
         Escpos.__init__(self, *args, **kwargs)
         self._output_list = []
 
     def _raw(self, msg):
-        """Print any command sent in raw format
+        """Print any command sent in raw format.
 
         :param msg: arbitrary code to be printed
         :type msg: bytes
@@ -377,11 +378,11 @@ class Dummy(Escpos):
 
     @property
     def output(self):
-        """Get the data that was sent to this printer"""
+        """Get the data that was sent to this printer."""
         return b"".join(self._output_list)
 
     def clear(self):
-        """Clear the buffer of the printer
+        """Clear the buffer of the printer.
 
         This method can be called if you send the contents to a physical printer
         and want to use the Dummy printer for new output.
@@ -389,13 +390,20 @@ class Dummy(Escpos):
         del self._output_list[:]
 
     def close(self):
+        """Close not implemented for Dummy printer."""
         pass
 
 
 if _WIN32PRINT:
 
     class Win32Raw(Escpos):
+        """Printer binding for win32 API.
+
+        Uses the module pywin32 for printing.
+        """
+
         def __init__(self, printer_name=None, *args, **kwargs):
+            """Initialize default printer."""
             Escpos.__init__(self, *args, **kwargs)
             if printer_name is not None:
                 self.printer_name = printer_name
@@ -405,6 +413,7 @@ if _WIN32PRINT:
             self.open()
 
         def open(self, job_name="python-escpos"):
+            """Open connection to default printer."""
             if self.printer_name is None:
                 raise Exception("Printer not found")
             self.hPrinter = win32print.OpenPrinter(self.printer_name)
@@ -414,6 +423,7 @@ if _WIN32PRINT:
             win32print.StartPagePrinter(self.hPrinter)
 
         def close(self):
+            """Close connection to default printer."""
             if not self.hPrinter:
                 return
             win32print.EndPagePrinter(self.hPrinter)
@@ -422,7 +432,7 @@ if _WIN32PRINT:
             self.hPrinter = None
 
         def _raw(self, msg):
-            """Print any command sent in raw format
+            """Print any command sent in raw format.
 
             :param msg: arbitrary code to be printed
             :type msg: bytes
@@ -448,7 +458,7 @@ if _CUPSPRINT:
         """
 
         def __init__(self, printer_name=None, *args, **kwargs):
-            """CupsPrinter class constructor.
+            """Class constructor for CupsPrinter.
 
             :param printer_name: CUPS printer name (Optional)
             :type printer_name: str
@@ -477,7 +487,7 @@ if _CUPSPRINT:
             return self.conn.getPrinters()
 
         def open(self, job_name="python-escpos"):
-            """Setup a new print job and target printer.
+            """Set up a new print job and target the printer.
 
             A call to this method is required to send new jobs to
             the same CUPS connection.
@@ -491,7 +501,7 @@ if _CUPSPRINT:
             self.tmpfile = tempfile.NamedTemporaryFile(delete=True)
 
         def _raw(self, msg):
-            """Append any command sent in raw format to temporary file
+            """Append any command sent in raw format to temporary file.
 
             :param msg: arbitrary code to be printed
             :type msg: bytes
@@ -582,7 +592,7 @@ if not sys.platform.startswith("win"):
             self.lp.terminate()
 
         def flush(self):
-            """End line and wait for new commands"""
+            """End line and wait for new commands."""
             if self.lp.stdin.writable():
                 self.lp.stdin.write(b"\n")
             if self.lp.stdin.closed is False:

test/conftest.py

@@ -1,4 +1,5 @@
 import pytest
+
 from escpos.printer import Dummy
 
 

test/test_abstract_base_class.py

@@ -1,16 +1,18 @@
 #!/usr/bin/python
 """verifies that the metaclass abc is properly used by ESC/POS
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 Patrick Kanzler
 :license: MIT
 """
 
-import pytest
-import escpos.escpos as escpos
 from abc import ABCMeta
 
+import pytest
+
+import escpos.escpos as escpos
+
 
 def test_abstract_base_class_raises():
     """test whether the abstract base class raises an exception for ESC/POS"""

test/test_cli.py

@@ -4,10 +4,12 @@
 
 
 import os
+import shutil
+import tempfile
+
 import pytest
 from scripttest import TestFileEnvironment as TFE
-import tempfile
+
-import shutil
 import escpos
 
 TEST_DIR = tempfile.mkdtemp() + "/cli-test"

test/test_function_barcode.py

@@ -1,10 +1,11 @@
 #!/usr/bin/python
 
-import escpos.printer as printer
-from escpos.capabilities import Profile, BARCODE_B
-from escpos.exceptions import BarcodeTypeError, BarcodeCodeError
 import pytest
 
+import escpos.printer as printer
+from escpos.capabilities import BARCODE_B, Profile
+from escpos.exceptions import BarcodeCodeError, BarcodeTypeError
+
 
 @pytest.mark.parametrize(
     "bctype,data,expected",

test/test_function_buzzer.py

@@ -1,5 +1,5 @@
-import six
 import pytest
+import six
 
 from escpos import printer
 from escpos.constants import BUZZER

test/test_function_cashdraw.py

@@ -1,8 +1,9 @@
 #!/usr/bin/python
 
+import pytest
+
 import escpos.printer as printer
 from escpos.exceptions import CashDrawerError
-import pytest
 
 
 def test_raise_CashDrawerError():

test/test_function_check_barcode.py

@@ -2,9 +2,10 @@
 # -*- coding: utf-8 -*-
 
 
-import escpos.printer as printer
 import pytest
 
+import escpos.printer as printer
+
 
 @pytest.mark.parametrize(
     "bctype,data",

test/test_function_image.py

@@ -9,7 +9,6 @@
 
 
 import pytest
-
 from PIL import Image
 
 import escpos.printer as printer

test/test_function_linedisplay.py

@@ -1,7 +1,7 @@
 #!/usr/bin/python
 """tests for line display
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2017 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT

test/test_function_panel_button.py

@@ -1,7 +1,7 @@
 #!/usr/bin/python
 """tests for panel button function
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT

test/test_function_qr_non-native.py

@@ -2,18 +2,18 @@
 #  -*- coding: utf-8 -*-
 """tests for the non-native part of qr()
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT
 """
 
 
-import pytest
 import mock
+import pytest
+from PIL import Image
 
 from escpos.printer import Dummy
-from PIL import Image
 
 
 @mock.patch("escpos.printer.Dummy.image", spec=Dummy)

test/test_function_set.py

@@ -1,9 +1,7 @@
 import six
 
 import escpos.printer as printer
-from escpos.constants import TXT_NORMAL, TXT_STYLE, SET_FONT
+from escpos.constants import SET_FONT, TXT_NORMAL, TXT_SIZE, TXT_STYLE
-from escpos.constants import TXT_SIZE
-
 
 # Default test, please copy and paste this block to test set method calls
 

test/test_function_softbarcode.py

@@ -1,9 +1,10 @@
 #!/usr/bin/python
 
-import escpos.printer as printer
 import barcode.errors
 import pytest
 
+import escpos.printer as printer
+
 
 @pytest.fixture
 def instance():

test/test_function_text.py

@@ -1,17 +1,18 @@
 #!/usr/bin/python
 """tests for the text printing function
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT
 """
 
 
-import pytest
-import mock
-from hypothesis import given, assume
 import hypothesis.strategies as st
+import mock
+import pytest
+from hypothesis import assume, given
+
 from escpos.printer import Dummy
 
 

test/test_functions.py

@@ -1,4 +1,5 @@
 import pytest
+
 from escpos.printer import Dummy
 
 

test/test_load_module.py

@@ -1,7 +1,7 @@
 #!/usr/bin/python
 """very basic test cases that load the classes
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT

test/test_magicencode.py

@@ -2,19 +2,20 @@
 #  -*- coding: utf-8 -*-
 """tests for the magic encode module
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT
 """
 
 
-import pytest
-from hypothesis import given, example
 import hypothesis.strategies as st
-from escpos.magicencode import MagicEncode, Encoder
+import pytest
-from escpos.katakana import encode_katakana
+from hypothesis import example, given
+
 from escpos.exceptions import CharCodeError, Error
+from escpos.katakana import encode_katakana
+from escpos.magicencode import Encoder, MagicEncode
 
 
 class TestEncoder:

test/test_printer_file.py

@@ -2,16 +2,15 @@
 #  -*- coding: utf-8 -*-
 """tests for the File printer
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT
 """
 
 
-import six
-
 import pytest
+import six
 from hypothesis import given, settings
 from hypothesis.strategies import text
 

test/test_printer_network.py

@@ -1,10 +1,12 @@
 #!/usr/bin/python
 
-import escpos.printer as printer
-import pytest
-import mock
 import socket
 
+import mock
+import pytest
+
+import escpos.printer as printer
+
 
 @pytest.fixture
 def instance():

test/test_profile.py

@@ -1,5 +1,6 @@
 import pytest
-from escpos.capabilities import get_profile, NotSupported, BARCODE_B, Profile
+
+from escpos.capabilities import BARCODE_B, NotSupported, Profile, get_profile
 
 
 @pytest.fixture

test/test_raise_arbitrary_error.py

@@ -1,7 +1,7 @@
 #!/usr/bin/python
 """test the raising of errors with the error module
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2017 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT
@@ -9,6 +9,7 @@
 
 
 import pytest
+
 import escpos
 import escpos.exceptions
 

test/test_with_statement.py

@@ -1,20 +1,21 @@
 #!/usr/bin/python
 """test the facility which enables usage of the with-statement
 
-:author: `Patrick Kanzler <patrick.kanzler@fablab.fau.de>`_
+:author: `Patrick Kanzler <dev@pkanzler.de>`_
 :organization: `python-escpos <https://github.com/python-escpos>`_
 :copyright: Copyright (c) 2016 `python-escpos <https://github.com/python-escpos>`_
 :license: MIT
 """
 
 
-import escpos.printer as printer
 import escpos.escpos as escpos
+import escpos.printer as printer
 
 
 def test_with_statement():
-    """Use with statement"""
+    """Use with statement
+
+    .. todo:: Extend these tests as they don't really do anything at the moment"""
     dummy_printer = printer.Dummy()
     with escpos.EscposIO(dummy_printer) as p:
         p.writelines("Some text.\n")
-    # TODO extend these tests as they don't really do anything at the moment

tox.ini

@@ -22,8 +22,9 @@ deps = jaconv
        pytest-mock
        hypothesis>4
        python-barcode
-commands = pytest --cov escpos --cov-report=xml
+commands = pytest
 passenv = ESCPOS_CAPABILITIES_PICKLE_DIR, ESCPOS_CAPABILITIES_FILE, CI, TRAVIS, TRAVIS_*, APPVEYOR, APPVEYOR_*, CODECOV_*
+setenv = PY_IGNORE_IMPORTMISMATCH=1
 
 [testenv:docs]
 basepython = python
@@ -39,7 +40,16 @@ commands = sphinx-build -W -b html -d {envtmpdir}/doctrees .  {envtmpdir}/html
 
 [testenv:flake8]
 basepython = python
-# TODO add flake8-future
-# TODO add flake8-docstrings
 deps = flake8
+       flake8-docstrings
 commands = flake8
+
+[testenv:mypy]
+basepython = python
+deps = mypy
+       types-six
+       types-PyYAML
+       types-appdirs
+       types-Pillow
+       jaconv
+commands = mypy src