pin_print/imageprinter.py

import argparse
import sys
import os
import six
from random import randint
from PIL import Image, ImageOps

ESC = b'\x1B'
ETX = b'\x03'
SO = b'\x0E'

GRAPHIC = b'\x1B'+b'\x2A'+b'\x01' #1B 2A
LINE_FEED = b'\n'
CARIDGE_RET = b'\x0D'
DATA = bytearray()
COLUMNS = 2000
H = COLUMNS // 256
L = COLUMNS % 256

def _to_column_format(im, line_height):
    """
    Extract slices of an image as equal-sized blobs of column-format data.

    :param im: Image to extract from
    :param line_height: Printed line height in dots
    """
    width_pixels, height_pixels = im.size
    top = 0
    left = 0
    blobs = []
    while left < width_pixels:
        remaining_pixels = width_pixels - left
        box = (left, top, left + line_height, top + height_pixels)
        #transform:             (size,                        method, data=None, resample=0, fill=1)
        slice = im.transform((line_height, height_pixels), Image.EXTENT, box)
        bytes = slice.tobytes()
        blobs.append(bytes)
        left += line_height
    return blobs

def _int_low_high(inp_number, out_bytes):
    """ Generate multiple bytes for a number: In lower and higher parts, or more parts as needed.
    to generate the H and L value
    :param inp_number: Input number
    :param out_bytes: The number of bytes to output (1 - 4).
    """
    max_input = (256 << (out_bytes * 8) - 1);
    if not 1 <= out_bytes <= 4:
        raise ValueError("Can only output 1-4 byes")
    if not 0 <= inp_number <= max_input:
        raise ValueError("Number too large. Can only output up to {0} in {1} byes".format(max_input, out_bytes))
    outp = b'';
    for _ in range(0, out_bytes):
        outp += six.int2byte(inp_number % 256)
        inp_number = inp_number // 256
    return outp


def print(filename, getlines=False):
    im = Image.open(filename)

    basewidth = 350
    # Initial rotate. mirror, and extract blobs for each 8 or 24-pixel row
    # Convert to black & white via greyscale (so that bits can be inverted)

    im = im.transpose(Image.ROTATE_270).transpose(Image.FLIP_LEFT_RIGHT)
    height_pixels, width_pixels = im.size

    if width_pixels > basewidth:
        wpercent = (basewidth/float(im.size[0]))
        hsize = int((float(im.size[1])*float(wpercent)))
        im = im.resize((basewidth,hsize), Image.NEAREST)

    height_pixels, width_pixels = im.size
    im = im.resize((height_pixels,int(width_pixels*1.5)), Image.ANTIALIAS)

    im = im.convert("L")  # Invert: Only works on 'L' images
    im = ImageOps.invert(im) # Bits are sent with 0 = white, 1 = black in ESC/POS
    im = im.convert("1") # Pure black and white
    #im.show()
    line_height = 1
    blobs = _to_column_format (im, line_height * 8);

    height_pixels, width_pixels = im.size

    if getlines:
        return len(blobs)

    else:
        with open('/dev/usb/lp0', 'wb') as fp:
            fp.write(ESC+b"@")
            fp.write(ESC+b"\x7B"+b"\x41")
            #fp.write(ESC + b"3" + six.int2byte(22)); # Adjust line-feed size
            fp.write(ESC + b"\x33" + bytes([22]));

            #fp.write(ESC + )
            fp.write(CARIDGE_RET)
            for blob in blobs:
                fp.write(GRAPHIC + _int_low_high( width_pixels, 2 ) + blob)
                fp.write(LINE_FEED)
            #fp.write(GRAPHIC + bytes([L,H]) + DATA)
            fp.write(ESC + b"2"); # Reset line-feed size