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103 lines
3.3 KiB
Python
103 lines
3.3 KiB
Python
import argparse
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import sys
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import os
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import six
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from random import randint
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from PIL import Image, ImageOps
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ESC = b'\x1B'
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ETX = b'\x03'
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SO = b'\x0E'
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GRAPHIC = b'\x1B'+b'\x2A'+b'\x01' #1B 2A
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LINE_FEED = b'\n'
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CARIDGE_RET = b'\x0D'
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DATA = bytearray()
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COLUMNS = 2000
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H = COLUMNS // 256
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L = COLUMNS % 256
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def _to_column_format(im, line_height):
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"""
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Extract slices of an image as equal-sized blobs of column-format data.
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:param im: Image to extract from
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:param line_height: Printed line height in dots
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"""
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width_pixels, height_pixels = im.size
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top = 0
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left = 0
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blobs = []
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while left < width_pixels:
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remaining_pixels = width_pixels - left
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box = (left, top, left + line_height, top + height_pixels)
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#transform: (size, method, data=None, resample=0, fill=1)
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slice = im.transform((line_height, height_pixels), Image.EXTENT, box)
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bytes = slice.tobytes()
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blobs.append(bytes)
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left += line_height
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return blobs
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def _int_low_high(inp_number, out_bytes):
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""" Generate multiple bytes for a number: In lower and higher parts, or more parts as needed.
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to generate the H and L value
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:param inp_number: Input number
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:param out_bytes: The number of bytes to output (1 - 4).
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"""
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max_input = (256 << (out_bytes * 8) - 1);
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if not 1 <= out_bytes <= 4:
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raise ValueError("Can only output 1-4 byes")
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if not 0 <= inp_number <= max_input:
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raise ValueError("Number too large. Can only output up to {0} in {1} byes".format(max_input, out_bytes))
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outp = b'';
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for _ in range(0, out_bytes):
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outp += six.int2byte(inp_number % 256)
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inp_number = inp_number // 256
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return outp
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def print(filename, getlines=False):
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im = Image.open(filename)
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basewidth = 350
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# Initial rotate. mirror, and extract blobs for each 8 or 24-pixel row
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# Convert to black & white via greyscale (so that bits can be inverted)
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im = im.transpose(Image.ROTATE_270).transpose(Image.FLIP_LEFT_RIGHT)
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height_pixels, width_pixels = im.size
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if width_pixels > basewidth:
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wpercent = (basewidth/float(im.size[0]))
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hsize = int((float(im.size[1])*float(wpercent)))
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im = im.resize((basewidth,hsize), Image.NEAREST)
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height_pixels, width_pixels = im.size
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im = im.resize((height_pixels,int(width_pixels*1.5)), Image.ANTIALIAS)
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im = im.convert("L") # Invert: Only works on 'L' images
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im = ImageOps.invert(im) # Bits are sent with 0 = white, 1 = black in ESC/POS
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im = im.convert("1") # Pure black and white
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#im.show()
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line_height = 1
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blobs = _to_column_format (im, line_height * 8);
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height_pixels, width_pixels = im.size
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if getlines:
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return len(blobs)
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else:
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with open('/dev/usb/lp0', 'wb') as fp:
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fp.write(ESC+b"@")
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fp.write(ESC+b"\x7B"+b"\x41")
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#fp.write(ESC + b"3" + six.int2byte(22)); # Adjust line-feed size
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fp.write(ESC + b"\x33" + bytes([22]));
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#fp.write(ESC + )
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fp.write(CARIDGE_RET)
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for blob in blobs:
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fp.write(GRAPHIC + _int_low_high( width_pixels, 2 ) + blob)
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fp.write(LINE_FEED)
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#fp.write(GRAPHIC + bytes([L,H]) + DATA)
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fp.write(ESC + b"2"); # Reset line-feed size
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