Fix printing via a Brother QL

src/printer.py

@@ -20,10 +20,11 @@ import numpy as np
 # Importing the modules needed for each supported printer Type
 import escpos.printer
 from brother_ql.models import ModelsManager
-from brother_ql.backends import backend_factory
+from brother_ql.backends import backend_factory, guess_backend
 from brother_ql.raster import BrotherQLRaster
 from brother_ql.conversion import convert
 from brother_ql.backends.helpers import send
+from brother_ql import create_label
 
 
 class PrinterType(Enum):
@@ -444,6 +445,7 @@ class BrotherPrinter(Printer):
             vendor_id=vendor_id,
             product_id=self.device_id,
             serial_number=serial_number,
+            label_type="62",
         )
         self.app.logger.debug("Created a Brother printer !")
         self.ready = True
@@ -462,86 +464,49 @@ class BrotherPrinter(Printer):
         """
         Print a raster image via a Brother QL printer
         """
-        # TODO : make this label type go in the configuration
+        self.ready = False
-        label_type = "62"
-        rotate = 0
-        dither = False
-
-        data = _process_image(self, path=data, max_width=720, max_height=720)
-        self.app.logger.debug("Printing image %s", data)
         try:
-            # Prepare the image for printing
+            selected_backend = guess_backend(self.printer_info.identifier)
-            qlr = BrotherQLRaster(self.printer_info["model"])
+            BACKEND_CLASS = backend_factory(selected_backend)['backend_class']
-
+            BACKEND_STRING_DESCR = self.printer_info.identifier
-            instructions = convert(
-                qlr=qlr,
-                images=[data],
-                label=label_type,
-                rotate=rotate,
-                threshold=70,
-                dither=dither,
-                compress=True,
-                red=False,
-                dpi_600=False,
-                hq=False,
-                cut=True,
-            )
-
-            # Debug logging
-            if os.getenv("FLASK_DEBUG"):
-                self.app.logger.debug(f"""
-                Print parameters:
-                - Label type: {label_type}
-                - Rotate: {rotate}
-                - Dither: {dither}
-                - Model: {self.printer_info['model']}
-                - Backend: {self.printer_info['backend']}
-                - Identifier: {self.printer_info['identifier']}
-                """)
-
-            # Try to print using Python API
-            # send() =  status = {
-            #     'instructions_sent': True, # The instructions were sent to the printer.
-            #     'outcome': 'unknown', # String description of the outcome of the sending operation like: 'unknown', 'sent', 'printed', 'error'
-            #     'printer_state': None, # If the selected backend supports reading back the printer state, this key will contain it.
-            #     'did_print': False, # If True, a print was produced. It defaults to False if the outcome is uncertain (due to a backend without read-back capability).
-            #     'ready_for_next_job': False, # If True, the printer is ready to receive the next instructions. It defaults to False if the state is unknown.
-            # }
-            status = send(
-                instructions=instructions,
-                printer_identifier=self.printer_info["identifier"],
-                backend_identifier="pyusb",
-            )
-            self.app.logger.debug("Status: " + str(status))
-
-            if (
-                not status["did_print"]
-                or status["outcome"] == "error"
-                or status["outcome"] == "unknown"
-            ):
-                raise RuntimeError("Failed to print using Python API")
-
-            # if status["printer_state"]:
-            #     self.ready = bool(status["printer_state"])
-            #     self.app.logger.debug("Printer is borky : " + str(self.ready))
-            # else:
-            #     self.ready = True
-
-        except usb.core.USBError as e:
-            # Treat timeout errors as successful since they often occur after print completion
-            if e.errno == 110:  # Operation timed out
-                self.app.logger.debug(
-                    "USB timeout occurred - this is normal and the print likely completed"
-                )
-                self.app.logger.debug("Print completed (timeout is normal)")
-                self.ready = True
-
-            self.app.logger.debug(f"USBError encountered: {e}")
-            raise RuntimeError from e
-
         except Exception as e:
-            self.app.logger.debug(f"Unexpected error during printing: {str(e)}")
+            self.app.logger.error("Couldn't guess the backend to use from the printer string descriptor")
-            raise RuntimeError from e
+
+        try:
+            im = Image.open(data)
+            qlr = BrotherQLRaster(self.printer_info.model)
+            create_label(qlr, im, self.printer_info.label_type, threshold=70, cut=False, rotate=0)
+
+            # noinspection PyCallingNonCallable
+            be = BACKEND_CLASS(BACKEND_STRING_DESCR)
+            be.write(qlr.data)
+            be.dispose()
+            del be
+        except Exception as e:
+            raise e
+
+    def _cut(self):
+        self.ready = False
+        try:
+            selected_backend = guess_backend(self.printer_info.identifier)
+            BACKEND_CLASS = backend_factory(selected_backend)['backend_class']
+            BACKEND_STRING_DESCR = self.printer_info.identifier
+        except Exception as e:
+            self.app.logger.error("Couldn't guess the backend to use from the printer string descriptor")
+
+        data = "src/static/images/1x1.png"
+        try:
+            im = Image.open(data)
+            qlr = BrotherQLRaster(self.printer_info.model)
+            create_label(qlr, im, self.printer_info.label_type, threshold=70, cut=True, rotate=0)
+
+            # noinspection PyCallingNonCallable
+            be = BACKEND_CLASS(BACKEND_STRING_DESCR)
+            be.write(qlr.data)
+            be.dispose()
+            del be
+        except Exception as e:
+            raise e
 
     def print_task(self, task_type, data):
         """Execute actual print based on task type"""
@@ -551,9 +516,10 @@ class BrotherPrinter(Printer):
                     match (task_type.value):
                         case "image":
                             self._print_img(data["img"])
+                            self.ready = True
                         case "cut":
-                            # The cut happens by default on Brother QL printers.
+                            self._cut()
-                            pass
+                            self.ready = True
                         case "text":
                             self._print_txt(data["txt"], signature=data["sign"])
                             self.ready = True

src/printers.py

@@ -159,6 +159,10 @@ class Printers:
 
         return None
 
+    def printers_info(self):
+        """Return the current list of printers"""
+        return self.printers
+
 class _FindClass:
     """
     Use by usb.core to modify the way USB devices are found