Clean up Python code formatting and structure

app/__main__.py

@@ -1,22 +1,44 @@
-from dymo_bluetooth import discover_printers, Canvas
+import argparse
 import asyncio
+from io import BytesIO
+
 import barcode
 from barcode.writer import ImageWriter
+from dymo_bluetooth import Canvas, discover_printers
 from PIL import Image, ImageDraw, ImageFont
-from io import BytesIO
-import argparse
+
+# Constants for image dimensions and barcode configuration
+DEFAULT_IMAGE_WIDTH = 500
+DEFAULT_IMAGE_HEIGHT = 35
+DEFAULT_FONT_SIZE = 28
+MAX_CANVAS_HEIGHT = 31
+BARCODE_MODULE_WIDTH = 2.0
+BARCODE_QUIET_ZONE = 2
+
+
+def _draw_image_to_canvas(img: Image.Image) -> Canvas:
+    """
+    Converts a PIL Image to a DYMO Canvas by drawing black pixels.
+    """
+    canvas = Canvas()
+    for y in range(img.height):
+        for x in range(img.width):
+            if img.getpixel((x, y)) == 0:  # Black pixel
+                canvas.set_pixel(x, y, True)
+    return canvas
+
 
 async def print_canvas(canvas: Canvas):
     """
     Prints a given Canvas object to a DYMO LetraTag 200B printer.
     """
     # Get a list of printers.
     printers = await discover_printers()
-    
-    if not len(printers) > 0:
-        print("no printer found")
+
+    if not printers:
+        print("No printer found")
         return
-    
+
     printer = printers[0]
 
     # Get the first discovered printer and print the
@@ -25,35 +47,32 @@ async def print_canvas(canvas: Canvas):
     await printer.print(canvas)
     await printer.disconnect()
 
+
 async def print_text(text_to_print: str, should_print: bool = False):
     """
     Generates an image with the given text and prints it to a DYMO LetraTag 200B.
     """
     # Create a new image with a white background.
     # The size is a bit arbitrary, we'll crop it later.
-    img = Image.new('1', (500, 35), 1)
+    img = Image.new("1", (DEFAULT_IMAGE_WIDTH, DEFAULT_IMAGE_HEIGHT), 1)
     draw = ImageDraw.Draw(img)
-    
+
     # Use a default font.
     try:
-        font = ImageFont.truetype("arial.ttf", 28)
+        font = ImageFont.truetype("arial.ttf", DEFAULT_FONT_SIZE)
     except IOError:
         font = ImageFont.load_default()
 
     # Draw the text and get its bounding box.
     draw.text((0, 0), text_to_print, font=font, fill=0)
-    
+
     # Crop the image to the text.
     bbox = img.getbbox()
     if bbox:
         img = img.crop(bbox)
 
     # Create a Canvas and draw the image on it.
-    canvas = Canvas()
-    for y in range(img.height):
-        for x in range(img.width):
-            if img.getpixel((x, y)) == 0:  # Black pixel
-                canvas.set_pixel(x, y, True)
+    canvas = _draw_image_to_canvas(img)
 
     if should_print:
         await print_canvas(canvas)
@@ -64,61 +83,67 @@ async def generate_and_print_barcode(text_to_encode: str, should_print: bool = F
     Generates a barcode for the given text and prints it to a DYMO LetraTag 200B.
     """
     # Generate a barcode as a PNG image in memory.
-    code128 = barcode.get_barcode_class('code128')
-    # Configure the writer to create a wider barcode with a quiet zone for better scanning.
-    writer = ImageWriter(format='PNG')
+    code128 = barcode.get_barcode_class("code128")
+    # Configure the writer to create a wider barcode with a quiet zone for better
+    # scanning.
+    writer = ImageWriter(format="PNG")
     barcode_instance = code128(text_to_encode, writer=writer)
-
-    # Define options for the barcode image. 'module_width' makes the bars thicker.
+
     options = {
-        'module_width': 2.0,  # Controls the width of the thinnest bar in mm
-        'quiet_zone': 2,      # Margin on the left and right of the barcode
-        'write_text': False,  # Do not write the text representation below the barcode
+        # Controls the width of the thinnest bar in mm
+        "module_width": BARCODE_MODULE_WIDTH,
+        # Margin on the left and right of the barcode
+        "quiet_zone": BARCODE_QUIET_ZONE,
+        # Do not write the text representation below the barcode
+        "write_text": False,
     }
     buffer = BytesIO()
     barcode_instance.write(buffer, options)
 
-    # Save the barcode to a file so you can inspect it.
-    with open("barcode.png", "wb") as f:
-        f.write(buffer.getvalue())
-
     # Open the image with Pillow.
     buffer.seek(0)
     img = Image.open(buffer)
 
     # Resize the image to fit the canvas height limit, maintaining aspect ratio.
-    max_height = 31
-    if img.height > max_height:
+    if img.height > MAX_CANVAS_HEIGHT:
         aspect_ratio = img.width / img.height
-        new_height = max_height
+        new_height = MAX_CANVAS_HEIGHT
         new_width = int(aspect_ratio * new_height)
         img = img.resize((new_width, new_height), Image.NEAREST)
 
     # Convert the image to 1-bit black and white.
-    img = img.convert('1')
+    img = img.convert("1")
 
     # Create a Canvas and draw the barcode on it.
-    canvas = Canvas()
-    for y in range(img.height):
-        for x in range(img.width):
-            if img.getpixel((x, y)) == 0:  # Black pixel
-                canvas.set_pixel(x, y, True)
+    canvas = _draw_image_to_canvas(img)
 
     if should_print:
         await print_canvas(canvas)
 
+
 async def main():
-    parser = argparse.ArgumentParser(description="Generate and print a barcode on a DYMO LetraTag 200B.")
-    parser.add_argument('text', nargs='?', default="1234567890",
-                        help='The text to encode in the barcode. Defaults to "1234567890".')
-    parser.add_argument('--type', choices=['text', 'barcode'], default='barcode',
-                        help='The type of print to generate.')
+    parser = argparse.ArgumentParser(
+        description="Generate and print a barcode on a DYMO LetraTag 200B."
+    )
+    parser.add_argument(
+        "text",
+        nargs="?",
+        default="1234567890",
+        help='The text to encode in the barcode. Defaults to "1234567890".',
+    )
+    parser.add_argument(
+        "--type",
+        choices=["text", "barcode"],
+        default="barcode",
+        help="The type of print to generate.",
+    )
     args = parser.parse_args()
-    
-    if args.type == 'barcode':
+
+    if args.type == "barcode":
         await generate_and_print_barcode(args.text, should_print=True)
     else:
         await print_text(args.text, should_print=True)
 
+
 if __name__ == "__main__":
-    asyncio.run(main())
+    asyncio.run(main())

web.py

@@ -1,28 +1,32 @@
-from flask import Flask, render_template, request, flash, redirect, url_for, get_flashed_messages
-import asyncio
-from app.__main__ import generate_and_print_barcode, print_text
 from random import randbytes
 
+from flask import Flask, flash, redirect, render_template, request, url_for
+
+from app.__main__ import generate_and_print_barcode, print_text
+
 app = Flask(__name__)
 app.secret_key = randbytes(5).hex()
 
-@app.route('/')
+
+@app.route("/")
 def index():
-    return render_template('index.html')
+    return render_template("index.html")
 
-@app.route('/print', methods=['POST'])
+
+@app.route("/print", methods=["POST"])
 async def print_label():
-    text_to_print = request.form['text']
-    print_type = request.form['type']
-    
-    if print_type == 'barcode':
+    text_to_print = request.form["text"]
+    print_type = request.form["type"]
+
+    if print_type == "barcode":
         await generate_and_print_barcode(text_to_print, should_print=True)
         flash("Printing barcode...")
     else:
         await print_text(text_to_print, should_print=True)
         flash("Printing text...")
-
-    return redirect(url_for('index'))
 
-if __name__ == '__main__':
-    app.run(debug=True, host='0.0.0.0')
+    return redirect(url_for("index"))
+
+
+if __name__ == "__main__":
+    app.run(debug=True, host="0.0.0.0")