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add implementation of GS v 0, GS ( L and GS *.

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- ported test cases for EscposImage class, copied over 1px and 2px test images from escpos-php
- added test cases over image print function
- updated QR tests to also include image output check
- updated CLI to match new image function options
This commit is contained in:
Michael Billington
2016-04-03 17:36:54 +10:00
parent 59afcf778f
commit b45afbb297
18 changed files with 416 additions and 71 deletions
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24
escpos/cli.py
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@@ -37,8 +37,8 @@ DEMO_FUNCTIONS = {
{'txt': 'Hello, World!\n',}
],
'qr': [
{'text': 'This tests a QR code'},
{'text': 'https://en.wikipedia.org/'}
{'content': 'This tests a QR code'},
{'content': 'https://en.wikipedia.org/'}
],
'barcodes_a': [
{'bc': 'UPC-A', 'code': '13243546576'},
@@ -87,7 +87,7 @@ ESCPOS_COMMANDS = [
},
'arguments': [
{
'option_strings': ('--text',),
'option_strings': ('--content',),
'help': 'Text to print as a qr code',
'required': True,
}
@@ -223,10 +223,26 @@ ESCPOS_COMMANDS = [
},
'arguments': [
{
'option_strings': ('--path_img',),
'option_strings': ('--img_source',),
'help': 'Path to image',
'required': True,
},
{
'option_strings': ('--impl',),
'help': 'Implementation to use',
'choices': ['bitImageRaster', 'bitImageColumn', 'graphics'],
},
{
'option_strings': ('--high_density_horizontal',),
'help': 'Image density (horizontal)',
'type': str_to_bool,
},
{
'option_strings': ('--high_density_vertical',),
'help': 'Image density (vertical)',
'type': str_to_bool,
},
],
},
{

58
escpos/escpos.py
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@@ -21,7 +21,7 @@ from .constants import *
from .exceptions import *
from abc import ABCMeta, abstractmethod # abstract base class support
from escpos.image import EscposImage
class Escpos(object):
""" ESC/POS Printer object
@@ -49,17 +49,53 @@ class Escpos(object):
"""
pass
def image(self, path_img):
""" Open and print an image file
def image(self, img_source, high_density_vertical = True, high_density_horizontal = True, impl = "graphics"):
""" Print an image
Prints an image. The image is automatically adjusted in size in order to print it.
:param img_source: PIL image or filename to load: `jpg`, `gif`, `png` or `bmp`
"""
im = EscposImage(img_source)
if impl == "bitImageRaster":
# GS v 0, raster format bit image
density_byte = (0 if high_density_vertical else 1) + (0 if high_density_horizontal else 2)
header = GS + b"v0" + six.int2byte(density_byte) + self._int_low_high(im.width_bytes, 2) + self._int_low_high(im.height, 2);
self._raw(header + im.to_raster_format())
if impl == "graphics":
# GS ( L raster format graphics
img_header = self._int_low_high(im.width, 2) + self._int_low_high(im.height, 2);
tone = b'0';
colors = b'1';
ym = six.int2byte(1 if high_density_vertical else 2)
xm = six.int2byte(1 if high_density_horizontal else 2)
header = tone + xm + ym + colors + img_header
raster_data = im.to_raster_format()
self._image_send_graphics_data(b'0', b'p', header + raster_data);
self._image_send_graphics_data(b'0', b'2', b'');
if impl == "bitImageColumn":
# ESC *, column format bit image
density_byte = (1 if high_density_horizontal else 0) + (32 if high_density_vertical else 0);
header = ESC + b"*" + six.int2byte(density_byte) + self._int_low_high( im.width, 2 );
outp = []
outp.append(ESC + b"3" + six.int2byte(16)) # Adjust line-feed size
for blob in im.to_column_format(high_density_vertical):
outp.append(header + blob + b"\n")
outp.append(ESC + b"2"); # Reset line-feed size
self._raw(b''.join(outp))
.. todo:: Seems to be broken. Write test that simply executes function with a dummy printer in order to
check for bugs like these in the future.
:param path_img: complete filename and path to image of type `jpg`, `gif`, `png` or `bmp`
def _image_send_graphics_data(self, m, fn, data):
"""
pass
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
:param data: Data to send
"""
header = self._int_low_high(len(data) + 2, 2);
self._raw(GS + b'(L' + header + m + fn + data)
def qr(self, content, ec=QR_ECLEVEL_L, size=3, model=QR_MODEL_2, native=False):
""" Print QR Code for the provided string
@@ -84,7 +120,7 @@ class Escpos(object):
if not native:
# Map ESC/POS error correction levels to python 'qrcode' library constant and render to an image
if model != QR_MODEL_2:
raise ValueError("Invalid QR mocel for qrlib rendering (must be QR_MODEL_2)")
raise ValueError("Invalid QR model for qrlib rendering (must be QR_MODEL_2)")
python_qr_ec = {
QR_ECLEVEL_H: qrcode.constants.ERROR_CORRECT_H,
QR_ECLEVEL_L: qrcode.constants.ERROR_CORRECT_L,
@@ -97,7 +133,7 @@ class Escpos(object):
qr_img = qr_code.make_image()
im = qr_img._img.convert("RGB")
# Convert the RGB image in printable image
self._convert_image(im)
self.image(im)
return
# Native 2D code printing
cn = b'1' # Code type for QR code

85
escpos/image.py Normal file
View File

@@ -0,0 +1,85 @@
""" Image format handling class
This module contains the image format handler :py:class:`EscposImage`.
The class is designed to efficiently delegate image processing to
PIL, rather than spend CPU cycles looping over pixels.
:author: `Michael Billington <michael.billington@gmail.com>`_
:organization: `python-escpos <https://github.com/python-escpos>`_
:copyright: Copyright (c) 2016 Michael Billington <michael.billington@gmail.com>
:license: GNU GPL v3
"""
from PIL import Image, ImageOps
class EscposImage(object):
def __init__(self, img_source):
"""
Load in an image
:param img_source: PIL.Image, or filename to load one from.
"""
if isinstance(img_source, Image.Image):
img_original = img_source
else:
img_original = Image.open(img_source)
# Convert to white RGB background, paste over white background
# to strip alpha.
img_original = img_original.convert('RGBA')
im = Image.new("RGB", img_original.size, (255, 255, 255))
im.paste(img_original, mask=img_original.split()[3])
# Convert down to greyscale
im = im.convert("L")
# Invert: Only works on 'L' images
im = ImageOps.invert(im)
# Pure black and white
self._im = im.convert("1")
@property
def width(self):
"""
Width of image in pixels
"""
width_pixels, _ = self._im.size
return width_pixels
@property
def width_bytes(self):
"""
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_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.
:param high_density_vertical: Printed line height in dots
"""
im = self._im.transpose(Image.ROTATE_270).transpose(Image.FLIP_LEFT_RIGHT)
line_height = 24 if high_density_vertical else 8
width_pixels, height_pixels = im.size
top = 0
left = 0
while left < width_pixels:
box = (left, top, left + line_height, top + height_pixels)
im_slice = im.transform((line_height, height_pixels), Image.EXTENT, box)
im_bytes = im_slice.tobytes()
yield(im_bytes)
left += line_height
def to_raster_format(self):
"""
Convert image to raster-format binary
"""
return self._im.tobytes()

35
escpos/printer.py
View File

@@ -20,7 +20,6 @@ import socket
from .escpos import Escpos
from .exceptions import *
class Usb(Escpos):
""" USB printer
@@ -260,3 +259,37 @@ class File(Escpos):
""" Close system file """
self.device.flush()
self.device.close()
class Dummy(Escpos):
""" 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
generating print jobs for later use, or testing output.
inheritance:
.. inheritance-diagram:: escpos.printer.Dummy
:parts: 1
"""
def __init__(self, *args, **kwargs):
"""
:param devfile : Device file under dev filesystem
"""
Escpos.__init__(self, *args, **kwargs)
self._output_list = []
def _raw(self, msg):
""" Print any command sent in raw format
:param msg: arbitrary code to be printed
:type msg: bytes
"""
self._output_list.append(msg)
@property
def output(self):
return b''.join(self._output_list)