inventree-phomemo-plugin/inventree_phomemo/phomemo_label.py

# translation
from django.utils.translation import gettext_lazy as _
from django.core.validators import MinValueValidator
from django.core.validators import MaxValueValidator

# printer supportt
import socket

# InvenTree plugin libs
from plugin import InvenTreePlugin
from plugin.mixins import LabelPrintingMixin, SettingsMixin

from inventree_phomemo.version import PHOMEMO_PLUGIN_VERSION

class PhomemoLabelPlugin(LabelPrintingMixin, SettingsMixin, InvenTreePlugin):
    AUTHOR = "Sergal.engineering"
    DESCRIPTION = "Label printing plugin for Phomemo printers"
    VERSION = PHOMEMO_PLUGIN_VERSION
    NAME = "Phomemo"
    SLUG = "phomemo"
    TITLE = "Phomemo Label Printer"

    SETTINGS = {
        'IP_ADDRESS': {
            'name': _('IP Address'),
            'description': _('IP address of phomemo print server'),
            'default': '',
        },
        'PORT': {
            'name': _('Port'),
            'description': _('Port of phomemo print server'),
            'default': '9100',
        },
        'THRESHOLD': {
            'name': _('Threshold'),
            'description': _('Threshold for B/W conversion (0-255)'),
            'validator': [int, MinValueValidator(0), MaxValueValidator(255)],
            'default': 200,
        },
    }

    def print_label(self, **kwargs):

        # Read settings
        ip_address = self.get_setting('IP_ADDRESS')
        port = int(self.get_setting('PORT'))
        threshold = self.get_setting('THRESHOLD')
        label_image = kwargs['png_file']

        # Extract width (x) and height (y) information.
        width = kwargs['width']
        height = kwargs['height']

        # convert image to B/W
        fn = lambda x: 255 if x > threshold else 0
        label_image = label_image.convert('L').point(fn, mode='1')

        ##### Convert to phomemo

        # Send the label to the printer
        try:
            print_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            print_socket.settimeout(5)
            print_socket.connect((ip_address, port))
            data = label_image.tobytes("PNG")
            print_socket.send(data.encode())
            print_socket.close()
        except Exception as error:
            raise ConnectionError('Error connecting to printer server: ' + str(error))