Merge pull request #78 from python-escpos/davisgoglin-merge-rebase

Davisgoglin merge rebase

escpos/__init__.py

@@ -1 +1,5 @@
+import constants
+import escpos
+import exceptions
+import printer
 __all__ = ["constants", "escpos", "exceptions", "printer"]

escpos/cli.py

@@ -0,0 +1,213 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+"""A simple command-line interface for common python-escpos functionality
+
+Usage: python -m escpos.cli --help
+
+Dependencies:
+- DavisGoglin/python-escpos or better
+- A file named weather.png (for the 'test' subcommand)
+
+Reasons for using the DavisGoglin/python-escpos fork:
+- image() accepts a PIL.Image object rather than requiring me to choose
+  between writing a temporary file to disk or calling a "private" method.
+- fullimage() allows me to print images of arbitrary length using slicing.
+
+How to print unsupported barcodes:
+    barcode -b 'BARCODE' -e 'code39' -E | convert -density 200% eps:- code.png
+    python test_escpos.py --images code.png
+
+Copyright (C) 2014 Stephan Sokolow (deitarion/SSokolow)
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
+OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+"""
+
+from __future__ import absolute_import
+
+__author__ = "Stephan Sokolow (deitarion/SSokolow)"
+__license__ = "MIT"
+
+import re
+
+from escpos import printer
+
+epson = printer.Usb(0x0416, 0x5011)
+# TODO: Un-hardcode this
+
+
+def _print_text_file(path):
+    """Print the given text file"""
+    epson.set(align='left')
+    with open(path, 'rU') as fobj:
+        for line in fobj:
+            epson.text(line)
+
+
+def _print_image_file(path):
+    """Print the given image file."""
+    epson.fullimage(path, histeq=False, width=384)
+
+
+def print_files(args):
+    """The 'print' subcommand"""
+    for path in args.paths:
+        if args.images:
+            _print_image_file(path)
+        else:
+            _print_text_file(path)
+    epson.cut()
+
+# {{{ 'echo' Subcommand
+
+KNOWN_BARCODE_TYPES = ['UPC-A', 'UPC-E', 'EAN13', 'ITF']
+re_barcode_escape = re.compile(r'^%(?P<type>\S+)\s(?P<data>[0-9X]+)$')
+
+
+def echo(args):  # pylint: disable=unused-argument
+    """TTY-like line-by-line keyboard-to-printer echo loop."""
+    try:
+        while True:
+            line = raw_input()
+            match = re_barcode_escape.match(line)
+            if match and match.group('type') in KNOWN_BARCODE_TYPES:
+                bctype, data = match.groups()
+                epson.barcode(data, bctype, 48, 2, '', '')
+                epson.set(align='left')
+            else:
+                epson.text('{0}\n'.format(line))
+    except KeyboardInterrupt:
+        epson.cut()
+
+# }}}
+# {{{ 'test' Subcommand
+
+from PIL import Image, ImageDraw
+
+
+def _stall_test(width, height):
+    """Generate a pattern to detect print glitches due to vertical stalling."""
+    img = Image.new('1', (width, height))
+    for pos in [(x, y) for y in range(0, height) for x in range(0, width)]:
+        img.putpixel(pos, not sum(pos) % 10)
+    return img
+
+
+def _test_basic():
+    """The original test code from python-escpos's Usage wiki page"""
+    epson.set(align='left')
+    # Print text
+    epson.text("TODO:\n")  # pylint: disable=fixme
+    epson.text("[ ] Task 1\n")
+    epson.text("[ ] Task 2\n")
+    # Print image
+    # TODO: Bundle an image so this can be used
+    # epson.image("weather.png")
+    # Print QR Code (must have a white border to be scanned)
+    epson.set(align='center')
+    epson.text("Scan to recall TODO list")  # pylint: disable=fixme
+    epson.qr("http://www.example.com/")
+    # Print barcode
+    epson.barcode('1234567890128', 'EAN13', 32, 2, '', '')
+    # Cut paper
+    epson.cut()
+
+
+def _test_barcodes():
+    """Print test barcodes for all ESCPOS-specified formats."""
+    for name, data in (
+            # pylint: disable=bad-continuation
+            ('UPC-A', '123456789012\x00'),
+            ('UPC-E', '02345036\x00'),
+            ('EAN13', '1234567890128\x00'),
+            ('EAN8', '12345670\x00'),
+            ('CODE39', 'BARCODE12345678\x00'),
+            ('ITF', '123456\x00'),
+            ('CODABAR', 'A40156B'),
+            # TODO: CODE93 and CODE128
+    ):
+        # TODO: Fix the library to restore old alignment somehow
+        epson.set(align='center')
+        epson.text('\n{0}\n'.format(name))
+        epson.barcode(data, name, 64, 2, '', '')
+
+
+def _test_patterns(width=384, height=255):
+    """Print a set of test patterns for raster image output."""
+    # Test our guess of the paper width
+    img = Image.new('1', (width, height), color=1)
+    draw = ImageDraw.Draw(img)
+    draw.polygon(((0, 0), img.size, (0, img.size[1])), fill=0)
+    epson.image(img)
+    del draw, img
+
+    # Test the consistency of printing large data and whether stall rate is
+    # affected by data rate
+    epson.image(_stall_test(width, height))
+    epson.image(_stall_test(width / 2, height))
+
+
+def test(args):
+    """The 'test' subcommand"""
+    if args.barcodes:
+        _test_barcodes()
+    elif args.patterns:
+        _test_patterns()
+    else:
+        _test_basic()
+
+
+# }}}
+
+def main():
+    """Wrapped in a function for import and entry point compatibility"""
+    # pylint: disable=bad-continuation
+
+    import argparse
+
+    parser = argparse.ArgumentParser(
+        description="Command-line interface to python-escpos")
+    subparsers = parser.add_subparsers(title='subcommands')
+
+    echo_parser = subparsers.add_parser('echo', help='Echo the keyboard to '
+                                                     'the printer line-by-line (Exit with Ctrl+C)')
+    echo_parser.set_defaults(func=echo)
+
+    print_parser = subparsers.add_parser('print', help='Print the given files')
+    print_parser.add_argument('--images', action='store_true',
+                              help="Provided files are images rather than text files.")
+    print_parser.add_argument('paths', metavar='path', nargs='+')
+    print_parser.set_defaults(func=print_files)
+
+    test_parser = subparsers.add_parser('test', help='Print test patterns')
+    test_modes = test_parser.add_mutually_exclusive_group()
+    test_modes.add_argument('--barcodes', action='store_true',
+                            help="Test supported barcode types (Warning: Some printers must be "
+                                 "reset after attempting an unsupported barcode type.)")
+    test_modes.add_argument('--patterns', action='store_true',
+                            help="Print test patterns")
+    test_parser.set_defaults(func=test)
+
+    args = parser.parse_args()
+    args.func(args)
+
+
+if __name__ == '__main__':
+    main()
+
+# vim: set sw=4 sts=4 :

escpos/constants.py

@@ -10,87 +10,127 @@ moved to `capabilities` as in `escpos-php by @mike42 <https://github.com/mike42/
 :license: GNU GPL v3
 """
 
+# Control characters
+# as labelled in http://www.novopos.ch/client/EPSON/TM-T20/TM-T20_eng_qr.pdf
+NUL = '\x00'
+EOT = '\x04'
+ENQ = '\x05'
+DLE = '\x10'
+DC4 = '\x14'
+CAN = '\x18'
+ESC = '\x1b'
+FS  = '\x1c'
+GS  = '\x1d'
+
 # Feed control sequences
-CTL_LF     = '\x0a'               # Print and line feed
+CTL_LF = '\n'             # Print and line feed
-CTL_FF     = '\x0c'               # Form feed
+CTL_FF = '\f'             # Form feed
-CTL_CR     = '\x0d'               # Carriage return
+CTL_CR = '\r'             # Carriage return
-CTL_HT     = '\x09'               # Horizontal tab
+CTL_HT = '\t'             # Horizontal tab
-CTL_SET_HT = '\x1b\x44'           # Set horizontal tab positions
+CTL_SET_HT = ESC + '\x44' # Set horizontal tab positions
-CTL_VT     = '\x1b\x64\x04'       # Vertical tab
+CTL_VT = '\v'             # Vertical tab
+
 # Printer hardware
-HW_INIT    = '\x1b\x40'           # Clear data in buffer and reset modes
+HW_INIT   = ESC + '@'             # Clear data in buffer and reset modes
-HW_SELECT  = '\x1b\x3d\x01'       # Printer select
+HW_SELECT = ESC + '=\x01'         # Printer select
-HW_RESET   = '\x1b\x3f\x0a\x00'   # Reset printer hardware
+
-# Cash Drawer
+HW_RESET  = ESC + '\x3f\x0a\x00'  # Reset printer hardware
-CD_KICK_2  = '\x1b\x70\x00'       # Sends a pulse to pin 2 []
+                                  # (TODO: Where is this specified?)
-CD_KICK_5  = '\x1b\x70\x01'       # Sends a pulse to pin 5 []
+
-# Paper
+#{ Cash Drawer (ESC p <pin> <on time: 2*ms> <off time: 2*ms>)
-PAPER_FULL_CUT  = '\x1d\x56\x00'  # Full cut paper
+_CASH_DRAWER = lambda m, t1='', t2='': ESC + 'p' + m + chr(t1) + chr(t2)
-PAPER_PART_CUT  = '\x1d\x56\x01'  # Partial cut paper
+CD_KICK_2 = _CASH_DRAWER('\x00', 50, 50)  # Sends a pulse to pin 2 []
+CD_KICK_5 = _CASH_DRAWER('\x01', 50, 50)  # Sends a pulse to pin 5 []
+
+# Paper Cutter
+_CUT_PAPER = lambda m: GS + 'V' + m
+PAPER_FULL_CUT = _CUT_PAPER('\x00')  # Full cut paper
+PAPER_PART_CUT = _CUT_PAPER('\x01')  # Partial cut paper
+
 # Text format
-TXT_NORMAL      = '\x1b\x21\x00'  # Normal text
+# TODO: Acquire the "ESC/POS Application Programming Guide for Paper Roll
-TXT_2HEIGHT     = '\x1b\x21\x10'  # Double height text
+#       Printers" and tidy up this stuff too.
-TXT_2WIDTH      = '\x1b\x21\x20'  # Double width text
+TXT_NORMAL     = ESC + '!\x00'     # Normal text
-TXT_4SQUARE     = '\x1b\x21\x30'  # Quad area text
+TXT_2HEIGHT    = ESC + '!\x10'     # Double height text
-TXT_UNDERL_OFF  = '\x1b\x2d\x00'  # Underline font OFF
+TXT_2WIDTH     = ESC + '!\x20'     # Double width text
-TXT_UNDERL_ON   = '\x1b\x2d\x01'  # Underline font 1-dot ON
+TXT_4SQUARE    = ESC + '!\x30'     # Quad area text
-TXT_UNDERL2_ON  = '\x1b\x2d\x02'  # Underline font 2-dot ON
+TXT_UNDERL_OFF = ESC + '\x2d\x00'  # Underline font OFF
-TXT_BOLD_OFF    = '\x1b\x45\x00'  # Bold font OFF
+TXT_UNDERL_ON  = ESC + '\x2d\x01'  # Underline font 1-dot ON
-TXT_BOLD_ON     = '\x1b\x45\x01'  # Bold font ON
+TXT_UNDERL2_ON = ESC + '\x2d\x02'  # Underline font 2-dot ON
-TXT_FONT_A      = '\x1b\x4d\x00'  # Font type A
+TXT_BOLD_OFF   = ESC + '\x45\x00'  # Bold font OFF
-TXT_FONT_B      = '\x1b\x4d\x01'  # Font type B
+TXT_BOLD_ON    = ESC + '\x45\x01'  # Bold font ON
-TXT_ALIGN_LT    = '\x1b\x61\x00'  # Left justification
+TXT_FONT_A     = ESC + '\x4d\x00'  # Font type A
-TXT_ALIGN_CT    = '\x1b\x61\x01'  # Centering
+TXT_FONT_B     = ESC + '\x4d\x01'  # Font type B
-TXT_ALIGN_RT    = '\x1b\x61\x02'  # Right justification
+TXT_ALIGN_LT   = ESC + '\x61\x00'  # Left justification
+TXT_ALIGN_CT   = ESC + '\x61\x01'  # Centering
+TXT_ALIGN_RT   = ESC + '\x61\x02'  # Right justification
+
 # Char code table
-CHARCODE_PC437  = '\x1b\x74\x00'  # USA: Standard Europe
+CHARCODE_PC437  = ESC + '\x74\x00'  # USA: Standard Europe
-CHARCODE_JIS    = '\x1b\x74\x01'  # Japanese Katakana
+CHARCODE_JIS    = ESC + '\x74\x01'  # Japanese Katakana
-CHARCODE_PC850  = '\x1b\x74\x02'  # Multilingual
+CHARCODE_PC850  = ESC + '\x74\x02'  # Multilingual
-CHARCODE_PC860  = '\x1b\x74\x03'  # Portuguese
+CHARCODE_PC860  = ESC + '\x74\x03'  # Portuguese
-CHARCODE_PC863  = '\x1b\x74\x04'  # Canadian-French
+CHARCODE_PC863  = ESC + '\x74\x04'  # Canadian-French
-CHARCODE_PC865  = '\x1b\x74\x05'  # Nordic
+CHARCODE_PC865  = ESC + '\x74\x05'  # Nordic
-CHARCODE_WEU    = '\x1b\x74\x06'  # Simplified Kanji, Hirakana
+CHARCODE_WEU    = ESC + '\x74\x06'  # Simplified Kanji, Hirakana
-CHARCODE_GREEK  = '\x1b\x74\x07'  # Simplified Kanji
+CHARCODE_GREEK  = ESC + '\x74\x07'  # Simplified Kanji
-CHARCODE_HEBREW = '\x1b\x74\x08'  # Simplified Kanji
+CHARCODE_HEBREW = ESC + '\x74\x08'  # Simplified Kanji
-CHARCODE_PC1252 = '\x1b\x74\x11'  # Western European Windows Code Set
+CHARCODE_PC1252 = ESC + '\x74\x11'  # Western European Windows Code Set
-CHARCODE_PC866  = '\x1b\x74\x12'  # Cirillic #2
+CHARCODE_PC866  = ESC + '\x74\x12'  # Cirillic #2
-CHARCODE_PC852  = '\x1b\x74\x13'  # Latin 2
+CHARCODE_PC852  = ESC + '\x74\x13'  # Latin 2
-CHARCODE_PC858  = '\x1b\x74\x14'  # Euro
+CHARCODE_PC858  = ESC + '\x74\x14'  # Euro
-CHARCODE_THAI42 = '\x1b\x74\x15'  # Thai character code 42
+CHARCODE_THAI42 = ESC + '\x74\x15'  # Thai character code 42
-CHARCODE_THAI11 = '\x1b\x74\x16'  # Thai character code 11
+CHARCODE_THAI11 = ESC + '\x74\x16'  # Thai character code 11
-CHARCODE_THAI13 = '\x1b\x74\x17'  # Thai character code 13
+CHARCODE_THAI13 = ESC + '\x74\x17'  # Thai character code 13
-CHARCODE_THAI14 = '\x1b\x74\x18'  # Thai character code 14
+CHARCODE_THAI14 = ESC + '\x74\x18'  # Thai character code 14
-CHARCODE_THAI16 = '\x1b\x74\x19'  # Thai character code 16
+CHARCODE_THAI16 = ESC + '\x74\x19'  # Thai character code 16
-CHARCODE_THAI17 = '\x1b\x74\x1a'  # Thai character code 17
+CHARCODE_THAI17 = ESC + '\x74\x1a'  # Thai character code 17
-CHARCODE_THAI18 = '\x1b\x74\x1b'  # Thai character code 18
+CHARCODE_THAI18 = ESC + '\x74\x1b'  # Thai character code 18
+
 # Barcode format
-BARCODE_TXT_OFF = '\x1d\x48\x00'  # HRI barcode chars OFF
+_SET_BARCODE_TXT_POS = lambda n: GS + 'H' + n
-BARCODE_TXT_ABV = '\x1d\x48\x01'  # HRI barcode chars above
+BARCODE_TXT_OFF = _SET_BARCODE_TXT_POS('\x00')  # HRI barcode chars OFF
-BARCODE_TXT_BLW = '\x1d\x48\x02'  # HRI barcode chars below
+BARCODE_TXT_ABV = _SET_BARCODE_TXT_POS('\x01')  # HRI barcode chars above
-BARCODE_TXT_BTH = '\x1d\x48\x03'  # HRI barcode chars both above and below
+BARCODE_TXT_BLW = _SET_BARCODE_TXT_POS('\x02')  # HRI barcode chars below
-BARCODE_FONT_A  = '\x1d\x66\x00'  # Font type A for HRI barcode chars
+BARCODE_TXT_BTH = _SET_BARCODE_TXT_POS('\x03')  # HRI both above and below
-BARCODE_FONT_B  = '\x1d\x66\x01'  # Font type B for HRI barcode chars
+
-BARCODE_HEIGHT  = '\x1d\x68\x64'  # Barcode Height [1-255]
+_SET_HRI_FONT = lambda n: GS + 'f' + n
-BARCODE_WIDTH   = '\x1d\x77\x03'  # Barcode Width  [2-6]
+BARCODE_FONT_A = _SET_HRI_FONT('\x00')  # Font type A for HRI barcode chars
-BARCODE_UPC_A   = '\x1d\x6b\x00'  # Barcode type UPC-A
+BARCODE_FONT_B = _SET_HRI_FONT('\x01')  # Font type B for HRI barcode chars
-BARCODE_UPC_E   = '\x1d\x6b\x01'  # Barcode type UPC-E
+
-BARCODE_EAN13   = '\x1d\x6b\x02'  # Barcode type EAN13
+BARCODE_HEIGHT = GS + 'h'  # Barcode Height [1-255]
-BARCODE_EAN8    = '\x1d\x6b\x03'  # Barcode type EAN8
+BARCODE_WIDTH  = GS + 'w'  # Barcode Width  [2-6]
-BARCODE_CODE39  = '\x1d\x6b\x04'  # Barcode type CODE39
+
-BARCODE_ITF     = '\x1d\x6b\x05'  # Barcode type ITF
+#NOTE: This isn't actually an ESC/POS command. It's the common prefix to the
-BARCODE_NW7     = '\x1d\x6b\x06'  # Barcode type NW7
+#      two "print bar code" commands:
+#      -  "GS k <type as integer> <data> NUL"
+#      -  "GS k <type as letter> <data length> <data>"
+#      The latter command supports more barcode types
+_SET_BARCODE_TYPE = lambda m: GS + 'k' + m
+BARCODE_UPC_A  = _SET_BARCODE_TYPE('\x00')  # Barcode type UPC-A
+BARCODE_UPC_E  = _SET_BARCODE_TYPE('\x01')  # Barcode type UPC-E
+BARCODE_EAN13  = _SET_BARCODE_TYPE('\x02')  # Barcode type EAN13
+BARCODE_EAN8   = _SET_BARCODE_TYPE('\x03')  # Barcode type EAN8
+BARCODE_CODE39 = _SET_BARCODE_TYPE('\x04')  # Barcode type CODE39
+BARCODE_ITF    = _SET_BARCODE_TYPE('\x05')  # Barcode type ITF
+BARCODE_NW7    = _SET_BARCODE_TYPE('\x06')  # Barcode type NW7
+
 # Image format
-S_RASTER_N      = '\x1d\x76\x30\x00'  # Set raster image normal size
+# NOTE: _PRINT_RASTER_IMG is the obsolete ESC/POS "print raster bit image"
-S_RASTER_2W     = '\x1d\x76\x30\x01'  # Set raster image double width
+#       command. The constants include a fragment of the data's header.
-S_RASTER_2H     = '\x1d\x76\x30\x02'  # Set raster image double height
+_PRINT_RASTER_IMG = lambda data: GS + 'v0' + data
-S_RASTER_Q      = '\x1d\x76\x30\x03'  # Set raster image quadruple
+S_RASTER_N  = _PRINT_RASTER_IMG('\x00')  # Set raster image normal size
+S_RASTER_2W = _PRINT_RASTER_IMG('\x01')  # Set raster image double width
+S_RASTER_2H = _PRINT_RASTER_IMG('\x02')  # Set raster image double height
+S_RASTER_Q  = _PRINT_RASTER_IMG('\x03')  # Set raster image quadruple
+
 # Printing Density
-PD_N50          = '\x1d\x7c\x00'  # Printing Density -50%
+PD_N50          = GS + '\x7c\x00'  # Printing Density -50%
-PD_N37          = '\x1d\x7c\x01'  # Printing Density -37.5%
+PD_N37          = GS + '\x7c\x01'  # Printing Density -37.5%
-PD_N25          = '\x1d\x7c\x02'  # Printing Density -25%
+PD_N25          = GS + '\x7c\x02'  # Printing Density -25%
-PD_N12          = '\x1d\x7c\x03'  # Printing Density -12.5%
+PD_N12          = GS + '\x7c\x03'  # Printing Density -12.5%
-PD_0            = '\x1d\x7c\x04'  # Printing Density  0%
+PD_0            = GS + '\x7c\x04'  # Printing Density  0%
-PD_P50          = '\x1d\x7c\x08'  # Printing Density +50%
+PD_P50          = GS + '\x7c\x08'  # Printing Density +50%
-PD_P37          = '\x1d\x7c\x07'  # Printing Density +37.5%
+PD_P37          = GS + '\x7c\x07'  # Printing Density +37.5%
-PD_P25          = '\x1d\x7c\x06'  # Printing Density +25%
+PD_P25          = GS + '\x7c\x06'  # Printing Density +25%
-PD_P12          = '\x1d\x7c\x05'  # Printing Density +12.5%
+PD_P12          = GS + '\x7c\x05'  # Printing Density +12.5%

escpos/escpos.py

@@ -15,15 +15,16 @@ except ImportError:
     from PIL import Image
 
 import qrcode
-import time
 import textwrap
 import binascii
+import operator
 
 from .constants import *
 from .exceptions import *
 
 from abc import ABCMeta, abstractmethod  # abstract base class support
 
+
 class Escpos(object):
     """ ESC/POS Printer object
 
@@ -62,9 +63,9 @@ class Escpos(object):
         else:
             image_border = 32 - (size % 32)
             if (image_border % 2) == 0:
-                return (round(image_border / 2), round(image_border / 2))
+                return round(image_border / 2), round(image_border / 2)
             else:
-                return (round(image_border / 2), round((image_border / 2) + 1))
+                return round(image_border / 2), round((image_border / 2) + 1)
 
     def _print_image(self, line, size):
         """ Print formatted image
@@ -161,6 +162,44 @@ class Escpos(object):
         # Convert the RGB image in printable image
         self._convert_image(im)
 
+    def fullimage(self, img, max_height=860, width=512, histeq=True, bandsize=255):
+        """ Resizes and prints an arbitrarily sized image """
+        if isinstance(img, (Image, Image.Image)):
+            im = img.convert("RGB")
+        else:
+            im = Image.open(img).convert("RGB")
+
+        if histeq:
+            # Histogram equaliztion
+            h = im.histogram()
+            lut = []
+            for b in range(0, len(h), 256):
+                # step size
+                step = reduce(operator.add, h[b:b+256]) / 255
+                # create equalization lookup table
+                n = 0
+                for i in range(256):
+                    lut.append(n / step)
+                    n = n + h[i+b]
+            im = im.point(lut)
+
+        if width:
+            ratio = float(width) / im.size[0]
+            newheight = int(ratio * im.size[1])
+
+            # Resize the image
+            im = im.resize((width, newheight), Image.ANTIALIAS)
+
+        if max_height and im.size[1] > max_height:
+            im = im.crop((0, 0, im.size[0], max_height))
+
+        # Divide into bands
+        current = 0
+        while current < im.size[1]:
+            self.image(im.crop((0, current, width or im.size[0],
+                                min(im.size[1], current + bandsize))))
+            current += bandsize
+
     def direct_image(self, image):
         """ Send image to printer
 
@@ -181,16 +220,16 @@ class Escpos(object):
         #self._raw(binascii.unhexlify(buf))
         for y in range(height):
             for x in range(width):
-                value = image.getpixel((x,y))
+                value = image.getpixel((x, y))
-                value = (value << 8) | value;
+                value |= (value << 8)
                 if value == 0:
                     temp |= mask
 
-                mask = mask >> 1
+                mask >>= 1
 
                 i += 1
                 if i == 8:
-                    buf +=   ("%02X" % temp)
+                    buf += ("%02X" % temp)
                     mask = 0x80
                     i = 0
                     temp = 0
@@ -205,7 +244,7 @@ class Escpos(object):
 
         :param text: text to generate a QR-Code from
         """
-        qr_code = qrcode.QRCode(version=4, box_size=4, border=1)
+        qr_code = qrcode.QRCode(version=4, box_size=4, border=1, error_correction=qrcode.constants.ERROR_CORRECT_H)
         qr_code.add_data(text)
         qr_code.make(fit=True)
         qr_img = qr_code.make_image()
@@ -268,7 +307,7 @@ class Escpos(object):
         else:
             raise CharCodeError()
 
-    def barcode(self, code, bc, width, height, pos, font):
+    def barcode(self, code, bc, height, width, pos, font):
         """ Print Barcode
 
         :param code: alphanumeric data to be printed as bar code
@@ -283,10 +322,10 @@ class Escpos(object):
             * NW7
 
             If none is specified, the method raises :py:exc:`~escpos.exceptions.BarcodeTypeError`.
-        :param width: barcode width, has to be between 1 and 255
-            *default*: 64
         :param height: barcode height, has to be between 2 and 6
             *default*: 3
+        :param width: barcode width, has to be between 1 and 255
+            *default*: 64
         :param pos: where to place the text relative to the barcode, *default*: below
 
             * ABOVE
@@ -306,15 +345,15 @@ class Escpos(object):
         # Align Bar Code()
         self._raw(TXT_ALIGN_CT)
         # Height
-        if height >= 2 or height <= 6:
+        if 1 <= height <= 255:
-            self._raw(BARCODE_HEIGHT)
+            self._raw(BARCODE_HEIGHT + chr(height))
         else:
-            raise BarcodeSizeError()
+            raise BarcodeSizeError("height = {height}".format(height=height))
         # Width
-        if width >= 1 or width <= 255:
+        if 2 <= width <= 6:
-            self._raw(BARCODE_WIDTH)
+            self._raw(BARCODE_WIDTH + chr(width))
         else:
-            raise BarcodeSizeError()
+            raise BarcodeSizeError("width = {width}".format(width=width))
         # Font
         if font.upper() == "B":
             self._raw(BARCODE_FONT_B)
@@ -342,10 +381,10 @@ class Escpos(object):
             self._raw(BARCODE_CODE39)
         elif bc.upper() == "ITF":
             self._raw(BARCODE_ITF)
-        elif bc.upper() == "NW7":
+        elif bc.upper() in ("NW7", "CODABAR"):
             self._raw(BARCODE_NW7)
         else:
-            raise BarcodeTypeError()
+            raise BarcodeTypeError(bc)
         # Print Code
         if code:
             self._raw(code)
@@ -373,7 +412,7 @@ class Escpos(object):
         :param columns: amount of columns
         :return: None
         """
-        colCount = self.columns if columns == None else columns
+        colCount = self.columns if columns is None else columns
         self.text(textwrap.fill(txt, colCount))
 
     def set(self, align='left', font='a', text_type='normal', width=1, height=1, density=9):

escpos/exceptions.py

@@ -11,6 +11,7 @@ Result/Exit codes:
     - `60` = Invalid pin to send Cash Drawer pulse :py:exc:`~escpos.exceptions.CashDrawerError`
     - `70` = Invalid number of tab positions :py:exc:`~escpos.exceptions.TabPosError`
     - `80` = Invalid char code :py:exc:`~escpos.exceptions.CharCodeError`
+    - `90` = USB device not found :py:exc:`~escpos.exceptions.USBNotFoundError`
 
 :author: `Manuel F Martinez <manpaz@bashlinux.com>`_ and others
 :organization: Bashlinux and `python-escpos <https://github.com/python-escpos>`_
@@ -45,7 +46,7 @@ class BarcodeTypeError(Error):
         self.resultcode = 10
 
     def __str__(self):
-        return "No Barcode type is defined"
+        return "No Barcode type is defined ({msg})".format(msg=self.msg)
 
 
 class BarcodeSizeError(Error):
@@ -61,7 +62,7 @@ class BarcodeSizeError(Error):
         self.resultcode = 20
 
     def __str__(self):
-        return "Barcode size is out of range"
+        return "Barcode size is out of range ({msg})".format(msg=self.msg)
 
 
 class BarcodeCodeError(Error):
@@ -151,3 +152,18 @@ class CharCodeError(Error):
 
     def __str__(self):
         return "Valid char code must be set"
+
+
+class USBNotFoundError(Error):
+    """ 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=""):
+        Error.__init__(self, msg)
+        self.msg = msg
+        self.resultcode = 90
+
+    def __str__(self):
+        return "USB device not found"

escpos/printer.py

@@ -13,7 +13,6 @@ import serial
 import socket
 
 from .escpos import *
-from .constants import *
 from .exceptions import *
 
 
@@ -32,7 +31,7 @@ class Usb(Escpos):
         :param out_ep: Output end point
         """
         Escpos.__init__(self, *args, **kwargs)
-        self.idVendor  = idVendor
+        self.idVendor = idVendor
         self.idProduct = idProduct
         self.interface = interface
         self.in_ep = in_ep
@@ -43,7 +42,7 @@ class Usb(Escpos):
         """ Search device on USB tree and set it as escpos device """
         self.device = usb.core.find(idVendor=self.idVendor, idProduct=self.idProduct)
         if self.device is None:
-            print("Cable isn't plugged in")
+            raise USBNotFoundError("Device not found or cable not plugged in.")
 
         check_driver = None
 
@@ -57,13 +56,13 @@ class Usb(Escpos):
                 self.device.detach_kernel_driver(0)
             except usb.core.USBError as e:
                 if check_driver is not None:
-                    print("Could not detatch kernel driver: %s" % str(e))
+                    print("Could not detatch kernel driver: {0}".format(str(e)))
 
         try:
             self.device.set_configuration()
             self.device.reset()
         except usb.core.USBError as e:
-            print("Could not set configuration: %s" % str(e))
+            print("Could not set configuration: {0}".format(str(e)))
 
     def _raw(self, msg):
         """ Print any command sent in raw format
@@ -100,10 +99,10 @@ class Serial(Escpos):
         :param dsrdtr:   Hardware flow control (False to enable RTS/CTS)
         """
         Escpos.__init__(self, *args, **kwargs)
-        self.devfile  = devfile
+        self.devfile = devfile
         self.baudrate = baudrate
         self.bytesize = bytesize
-        self.timeout  = timeout
+        self.timeout = timeout
         self.parity = parity
         self.stopbits = stopbits
         self.xonxoff = xonxoff
@@ -121,7 +120,7 @@ class Serial(Escpos):
         if self.device is not None:
             print("Serial printer enabled")
         else:
-            print("Unable to open serial printer on: %s" % self.devfile)
+            print("Unable to open serial printer on: {0}".format(str(self.devfile)))
 
     def _raw(self, msg):
         """ Print any command sent in raw format
@@ -160,14 +159,14 @@ class Network(Escpos):
         self.device.connect((self.host, self.port))
 
         if self.device is None:
-            print("Could not open socket for %s" % self.host)
+            print("Could not open socket for {0}".format(self.host))
 
     def _raw(self, msg):
         """ Print any command sent in raw format
 
         :param msg: arbitrary code to be printed
         """
-        self.device.send(msg)
+        self.device.sendall(msg)
 
     def __del__(self):
         """ Close TCP connection """
@@ -196,7 +195,7 @@ class File(Escpos):
         self.device = open(self.devfile, "wb")
 
         if self.device is None:
-            print("Could not open the specified file %s" % self.devfile)
+            print("Could not open the specified file {0}".format(self.devfile))
 
     def flush(self):
         """ Flush printing content """
@@ -208,9 +207,9 @@ class File(Escpos):
         :param msg: arbitrary code to be printed
         """
         if type(msg) is str:
-            self.device.write(msg.encode());
+            self.device.write(msg.encode())
         else:
-            self.device.write(msg);
+            self.device.write(msg)
 
     def __del__(self):
         """ Close system file """

setup.py

@@ -5,10 +5,12 @@ import sys
 from setuptools import setup
 from setuptools.command.test import test as TestCommand
 
+
 def read(fname):
     """read file from same path as setup.py"""
     return open(os.path.join(os.path.dirname(__file__), fname)).read()
 
+
 class Tox(TestCommand):
     """proxy class that enables tox to be run with setup.py test"""
     user_options = [('tox-args=', 'a', "Arguments to pass to tox")]
@@ -26,7 +28,7 @@ class Tox(TestCommand):
 
     def run_tests(self):
         """run tox and pass on user-options"""
-        #import here, cause outside the eggs aren't loaded
+        # import here, cause outside the eggs aren't loaded
         import tox
         import shlex
         args = self.tox_args