Change Error to warning when not on a Raspberry

because this is a real-time command, we might not get the good answer
and fail to print fast enough. See https://download4.epson.biz/sec_pubs/pos/reference_en/escpos/realtime_commands.html

src/main.py

@@ -90,7 +90,7 @@ if not os.getenv("FLASK_DEBUG") is None and os.getenv("FLASK_DEBUG") is True:
 app.secret_key = configuration_file["secrets"]["flask_secret_key"]
 app.config["UPLOAD_FOLDER"] = UPLOAD_FOLDER
 app.config["ALLOWED_EXTENSIONS"] = ALLOWED_EXTENSIONS
-app.config["MAX_CONTENT_LENGTH"] = 10 * 1000 * 1000  # Maximum 3Mb for a file upload
+app.config["MAX_CONTENT_LENGTH"] = 10 * 1000 * 1000  # Maximum 10Mb for a file upload
 app.config["TEMPLATES_AUTO_RELOAD"] = True
 
 # Queue creation
@@ -123,6 +123,8 @@ limiter = Limiter(
 )
 
 
+app.logger.info("🖶 Welcome to LittlePrynter !")
+
 # General routes
 @app.route("/")
 @limiter.limit("1/second", override_defaults=False)
@@ -189,6 +191,9 @@ def web_print_img():
             "No signature found for this print, using default signature : %s", str(e)
         )
         sign = configuration_file["defaults"]["signature"]
+    except werkzeug.exceptions.RequestEntityTooLarge as e:
+        flash("Whoops, image is too big: " + str(e), "error")
+        return redirect(url_for("index"))
 
     # check if the post request has the file part
     if "img" not in request.files:

src/printer.py

@@ -6,12 +6,11 @@ import os.path
 import os
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
-
+import time
 from enum import Enum
 import uuid
 import threading
 import usb.core
-
 from PIL import Image, ImageEnhance
 import numpy as np
 
@@ -176,7 +175,7 @@ class EscPosPrinter(Printer):
                 return True
 
     def _print_txt(self, msg, signature="", bold=False):
-
+        self.ready = False
         if not isinstance(msg, str):
             self.app.logger.error(
                 "It is not possible to print a " + str(type(msg)) + ", only strings."
@@ -225,9 +224,10 @@ class EscPosPrinter(Printer):
             ) from e
 
         self.app.logger.info("Printed text")
-        return True
+        self.ready = True
 
     def _print_img(self, path, signature="", center=True, process=False):
+        self.ready = False
         clean_signature = str(signature)
 
         if len(signature) > 256:
@@ -253,30 +253,33 @@ class EscPosPrinter(Printer):
         if process:
             try:
                 self.app.logger.debug("Proccessing the image")
-                path = _process_image(self, path)
+                processed_path = _process_image(self, path)
             except RuntimeError as e:
                 self.app.logger.error(
                     "Error while processing the image, aborting print : %s", str(e)
                 )
                 raise e
         else:
+            processed_path = path
             self.app.logger.warning("Not proccessing the image")
 
         try:
             self.printer.open(self.usb_args)
-            self.printer.image(path, center=center)
+            self.printer.image(processed_path, center=center)
             self.printer.textln(signature)
             self.printer.close()
-            self.app.logger.debug("Printed an image : " + str(path))
+            self.app.logger.debug("Printed an image : " + str(processed_path))
         except Exception as e:
             self.app.logger.error(str(e))
             raise RuntimeError("Could not print the picture") from e
         finally:
             try:
                 os.remove(path)
+                os.remove(processed_path)
             except OSError as e:
                 raise e
 
+            self.app.logger.debug("Removed image : " + str(processed_path))
             self.app.logger.debug("Removed image : " + str(path))
 
             try:
@@ -288,9 +291,10 @@ class EscPosPrinter(Printer):
                 raise RuntimeError("Could not close the printer connexion. ") from e
 
         self.app.logger.info("Printed a picture")
-        return True
+        self.ready = True
 
     def _qr(self, content):
+        self.ready = False
         try:
             self.printer.open(self.usb_args)
             self.printer.qr(content, center=True)
@@ -302,8 +306,10 @@ class EscPosPrinter(Printer):
             raise e
 
         self.app.logger.info("Printed a QR")
+        self.ready = True
 
     def _cut(self):
+        self.ready = False
         try:
             self.printer.open(self.usb_args)
             self.printer.cut()
@@ -314,39 +320,56 @@ class EscPosPrinter(Printer):
             raise e
 
         self.app.logger.info("Did a cut")
-        return True
+        self.ready = True
 
-    def _state(self):
+    def _state(self) -> bool:
-        return self.printer.is_online() and self.ready and self._has_paper()
+        has_paper = self._has_paper()
+        is_ready = self.ready
+
+        self.app.logger.debug("Has paper : %s " , has_paper )
+        self.app.logger.debug("Ready : %s " , is_ready )
+
+        return is_ready and has_paper # and is_online
 
     def print_task(self, task_type, data):
         """Execute actual print based on task type"""
-        with self._lock:
-            if self._state:
-                self._state = False
-                try:
-                    match (task_type.value):
-                        case "text":
-                            self._print_txt(data["txt"], signature=data["sign"])
-                            self._state = True
-                        case "image":
-                            self._print_img(
-                                data["img"], signature=data["sign"], process=data["process"]
-                            )
-                            self._state = True
-                        case "cut":
-                            self._cut()
-                            self._state = True
-                        case "qr":
-                            self._qr(data["txt"])
-                            self._state = True
-                        case _:
-                            raise RuntimeError("This task type is not supported")
-                except Exception as e:
-                    self._state = True
-                    raise RuntimeError from e
 
-                raise RuntimeError("The printer is not ready to print yet !")
+
+        with self._lock:
+            self.app.logger.debug("Acquired lock to start print")
+
+            i_m_ready = self._state()
+            while not i_m_ready:
+                self.app.logger.debug("Waiting for the printer to become ready, current state %s ", str(i_m_ready))
+                i_m_ready = self._state()
+                time.sleep(0.3)
+
+            self.app.logger.debug("Checked state to start printing : %s", self._state())
+            self.ready = False
+            try:
+                self.app.logger.debug("Checking task type")
+                match (task_type.value):
+                    case "text":
+
+                        self._print_txt(data["txt"], signature=data["sign"])
+                        self.ready = True
+                    case "image":
+                        self._print_img(
+                            data["img"], signature=data["sign"], process=data["process"]
+                        )
+                        self.ready = True
+                    case "cut":
+                        self._cut()
+                        self.ready = True
+                    case "qr":
+                        self._qr(data["txt"])
+                        self.ready = True
+                    case _:
+                        raise RuntimeError("This task type is not supported")
+            except Exception as e:
+                self.app.logger.debug("Exception occured while printing %s", str(e))
+                self.ready = True
+                raise RuntimeError from e
 
 
 class BrotherPrinter(Printer):
@@ -519,14 +542,14 @@ class BrotherPrinter(Printer):
 def _process_image(self, path):
     brightness_factor = 1.5  # Used only if image is too dark
     brightness_threshold = 100  # Brightness threshold (0–255)
-    # contrast_factor = 0.6  # Less than 1.0 = lower contrast
+    contrast_factor = 2  # Less than 1.0 = lower contrast
     max_width = 575
     max_height = 1000
 
     with Image.open(path) as original_img:
         # Convert to RGB if needed (JPEG doesn't support alpha)
         if original_img.mode in ("RGBA", "P"):
-            self.app.logger.debug("Converting the image to RGB from RGBA")
+            self.app.logger.debug("Converting the image from RGBA to RGBA")
             original_img = original_img.convert("RGB")
 
         # Resize while maintaining aspect ratio
@@ -556,16 +579,19 @@ def _process_image(self, path):
             self.app.logger.debug(
                 f"Image too dark, increasing brightness by a factor of {brightness_factor:.2f}"
             )
-            enhancer = ImageEnhance.Brightness(original_img)
+            enhancer = ImageEnhance.Brightness(grayscale)
-            original_img = enhancer.enhance(brightness_factor)
+            grayscale = enhancer.enhance(brightness_factor)
 
-        # # Reduce contrast
+        # Computer current contrast of grayscale image
-        # contrast_enhancer = ImageEnhance.Contrast(original_img)
+        contrast = np.clip(np.std(np.array(grayscale)), 0, 255)
-        # original_img = contrast_enhancer.enhance(contrast_factor)
+        self.app.logger.debug("Standard deviation of the contrast : %s", contrast)
+        # # Enhance contrast
+        contrast_enhancer = ImageEnhance.Contrast(grayscale)
+        original_img = contrast_enhancer.enhance(contrast_factor)
 
         # Convert to JPEG and save
         jpeg_path = os.path.splitext(path)[0] + "_processed.jpg"
-        original_img.save(jpeg_path, format="JPEG", quality=95, optimize=True)
+        grayscale.save(jpeg_path, format="JPEG", quality=95, optimize=True)
         self.app.logger.debug("Processed and saved image.")
 
     return jpeg_path

src/printers.py

@@ -111,6 +111,11 @@ class Printers:
                 self.app.logger.debug("Found a %s printer" , manufacturer)
 
         self.app.logger.debug("Found %s printers" , len(printers))
+
+        if len(printers) < 1:
+            self.app.logger.warning("Not printers found ! Please plug in a Printer and restart the program.")
+            raise RuntimeError("No printers found")
+
         return printers
 
     def any(self) -> Printer:

src/raspberry.py

@@ -68,7 +68,7 @@ class Raspberry:
                     self.app.logger.warning(
                         "Couldn't get sufficient hardware information from /proc/cpuinfo"
                     )
-                    self.app.logger.error("Unable to determine if we are on a Raspberry Pi.")
+                    self.app.logger.warning("Unable to determine if we are on a Raspberry Pi.")
                     return False
         except IOError:
             self.app.logger.error("Unable to open `/proc/cpuinfo`.")

src/web.py

@@ -44,7 +44,7 @@ class Web:
             file_uploaded = self.upload_file(image)
         except Exception as e:
             self.app.logger.error(e)
-            raise RuntimeError("Could not upload file") from e
+            raise RuntimeError("Could not upload file : " + str(e)) from e
 
         if file_uploaded:
             self.app.logger.debug("File has been uploaded, printing...")
@@ -100,7 +100,7 @@ class Web:
                     image.save(os.path.join(self.app.config["UPLOAD_FOLDER"], filename))
                 except OSError as e:
                     self.app.logger.error("Could not save file %s", e)
-                    return False
+                    raise RuntimeError("An OS error occured while uploading this file : " + str(e)) from e
 
                 self.app.logger.debug(
                     "File saved to "
@@ -111,7 +111,7 @@ class Web:
         self.app.logger.error(
             "Could not save file because the filename is forbidden"
         )
-        return False
+        raise RuntimeError("This file type is forbidden.")
 
     def get_queue_state(self):
         """Return current queue state"""

src/worker.py

@@ -64,7 +64,7 @@ class PrintWorker(threading.Thread):
                         "Ready" if self.printer.ready else "Not ready",
                     )
                 except Exception as e:
-                    self.app.logger.error(str(e))
+                    self.app.logger.error("No printer detected" + str(e))
                     self.printer = None
 
             if self.state != "idle":