Fix style

zebra_plugin.py

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+"""
+Label printing plugin for InvenTree.
+
+Supports direct printing of labels on label printers
+"""
+# translation
+from django.utils.translation import gettext_lazy as _
+from django.core.validators import MinValueValidator
+from django.core.validators import MaxValueValidator
+
+# InvenTree plugin libs
+from plugin import InvenTreePlugin
+from plugin.mixins import LabelPrintingMixin, SettingsMixin
+
+# Zebra printer support
+import zpl
+import socket
+
+from inventree_zebra.version import ZEBRA_PLUGIN_VERSION
+
+
+class ZebraLabelPlugin(LabelPrintingMixin, SettingsMixin, InvenTreePlugin):
+
+    AUTHOR = "Michael Buchmann"
+    DESCRIPTION = "Label printing plugin for Zebra printers"
+    VERSION = ZEBRA_PLUGIN_VERSION
+    NAME = "Zebra"
+    SLUG = "zebra"
+    TITLE = "Zebra Label Printer"
+
+    SETTINGS = {
+        'CONNECTION': {
+            'name': _('Printer Interface'),
+            'description': _('Select local or network printer'),
+            'choices': [('local', 'Local printer e.g. USB'),
+                        ('network', 'Network printer with IP address')],
+            'default': 'local',
+        },
+        'IP_ADDRESS': {
+            'name': _('IP Address'),
+            'description': _('IP address in case of network printer'),
+            'default': '',
+        },
+        'PORT': {
+            'name': _('Port'),
+            'description': _('Network port in case of network printer'),
+            'default': '9100',
+        },
+        'LOCAL_IF': {
+            'name': _('Local Device'),
+            'description': _('Interface of local printer'),
+            'default': '/dev/usb/lp0',
+        },
+        'THRESHOLD': {
+            'name': _('Threshold'),
+            'description': _('Threshold for converting gray scale to BW (0-255)'),
+            'validator': [int, MinValueValidator(0), MaxValueValidator(255)],
+            'default': 200,
+        },
+        'DARKNESS': {
+            'name': _('Darkness'),
+            'description': _('Darkness of the print out. 0-30'),
+            'validator': [int, MinValueValidator(0), MaxValueValidator(30)],
+            'default': 20,
+        },
+        'DPMM': {
+            'name': _('Dots per mm'),
+            'description': _('The resolution of the printer'),
+            'choices': [(8, '8 dots per mm'), (12, '12 dots per mm'), (24, '24 dots per mm')],
+            'default': 8,
+        },
+        'PRINTER_INIT': {
+            'name': _('Printer Init'),
+            'description': _('Additional ZPL commands sent to the printer. Use carefully!'),
+            'default': '~TA000~JSN^LT0^MNW^MTT^PMN^PON^PR2,2^LRN',
+        },
+    }
+
+    def print_label(self, **kwargs):
+
+        # Read settings
+        connection = self.get_setting('CONNECTION')
+        interface = self.get_setting('LOCAL_IF')
+        port = int(self.get_setting('PORT'))
+        threshold = self.get_setting('THRESHOLD')
+        darkness = self.get_setting('DARKNESS')
+        dpmm = int(self.get_setting('DPMM'))
+        printer_init = self.get_setting('PRINTER_INIT')
+        label_image = kwargs['png_file']
+
+        # Extract width (x) and height (y) information.
+        width = kwargs['width']
+        height = kwargs['height']
+
+        # Set the darkness
+        fn = lambda x: 255 if x > threshold else 0
+        label_image = label_image.convert('L').point(fn, mode='1')
+
+        # Uncomment this if you need the intermediate png file for debugging.
+        # label_image.save('/home/user/label.png')
+
+        # Convert image to Zebra zpl
+        li = zpl.Label(height, width, dpmm)
+        li.set_darkness(darkness)
+        li.labelhome(0, 0)
+        li.zpl_raw(printer_init)
+        li.origin(0, 0)
+        li.write_graphic(label_image, width)
+        li.endorigin()
+
+        # Uncomment this if you need the intermediate zpl file for debugging.
+        # datafile=open('/home/user/label.txt','w')
+        # datafile.write(li.dumpZPL())
+        # datafile.close()
+
+        # Select the right printer.
+        # This is a multi printer hack. In case the label has an IP address in the metadata
+        # the address in the settings is overwritten be the metadata. By this you can
+        # specify a separate printer for each label.
+
+        label = kwargs['label_instance']
+        try:
+            ip_address = label.metadata['ip_address']
+        except Exception:
+            ip_address = self.get_setting('IP_ADDRESS')
+
+        # Send the label to the printer
+        if (connection == 'local'):
+            try:
+                pass
+                printer = open(interface, 'w')
+                printer.write(li.dumpZPL())
+                printer.close()
+            except Exception as error:
+                raise ConnectionError('Error connecting to local printer: ' + str(error))
+        elif (connection == 'network'):
+            try:
+                mysocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                mysocket.connect((ip_address, port))
+                data = li.dumpZPL()
+                mysocket.send(data.encode())
+                mysocket.close()
+            except Exception as error:
+                raise ConnectionError('Error connecting to network printer: ' + str(error))
+        else:
+            print('Unknown Interface')