Update the way a printer is found, update the configuration of Brother
Printers
This commit is contained in:
n07070
176
src/printer.py
176
src/printer.py
@@ -11,9 +11,12 @@ from enum import Enum
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import uuid
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import threading
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import usb.core
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from PIL import Image, ImageEnhance
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from pathlib import Path
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from uuid import uuid4
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from PIL import Image, ImageEnhance, ImageDraw, ImageFont
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import numpy as np
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# Importing the modules needed for each supported printer Type
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import escpos.printer
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from brother_ql.models import ModelsManager
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@@ -386,8 +389,9 @@ class BrotherPrinter(Printer):
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"""
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def __init__(self, app, vendor_id, device_id):
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super().__init__(
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app, vendor_id, device_id, printer_type=PrinterType.BROTHER
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app, vendor_id, device_id, printer_type=PrinterType.BROTHER
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)
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self.printer = None
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self.usb_args = {}
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@@ -450,16 +454,21 @@ class BrotherPrinter(Printer):
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def _state(self):
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return self.ready
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def _print_txt(self, msg, signature="", bold=False):
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"""Print text after converting it to an image"""
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self._print_img(text_to_image(msg))
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def _print_img(self, data):
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"""
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Print a raster image via a Brother QL printer
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"""
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label_type = "102"
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# TODO : make this label type go in the configuration
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label_type = "62"
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rotate = 0
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dither = False
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data = _process_image(self, path=data, max_width=720, max_height=720)
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self.app.logger.debug("Printing image %s", data)
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try:
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# Prepare the image for printing
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qlr = BrotherQLRaster(self.printer_info["model"])
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@@ -545,6 +554,9 @@ class BrotherPrinter(Printer):
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case "cut":
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# The cut happens by default on Brother QL printers.
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pass
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case "text":
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self._print_txt(data["txt"], signature=data["sign"])
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self.ready = True
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case _:
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raise RuntimeError("This task type is not supported")
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except Exception as e:
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@@ -559,56 +571,128 @@ class BrotherPrinter(Printer):
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def _process_image(self, path, max_width=575, max_height=1000):
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brightness_factor = 1.5 # Used only if image is too dark
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brightness_threshold = 100 # Brightness threshold (0–255)
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contrast_factor = 2 # Less than 1.0 = lower contrast
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brightness_threshold = 100
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contrast_factor = 2.0
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with Image.open(path) as original_img:
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# Convert to RGB if needed (JPEG doesn't support alpha)
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if original_img.mode in ("RGBA", "P"):
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self.app.logger.debug("Converting the image from RGBA to RGBA")
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original_img = original_img.convert("RGB")
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# Resize while maintaining aspect ratio
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original_img = original_img.resize((max_width, max_height), Image.Resampling.LANCZOS)
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self.app.logger.debug("Resized the image")
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# # Convert to grayscale for dithering
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# dithered_img = original_img.convert("L").convert("1")
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# Dithering using default method (Floyd–Steinberg)
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# self.app.logger.debug("Dithered the image")
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# Compute brightness of original image (grayscale average)
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grayscale = original_img.convert("L")
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avg_brightness = np.array(grayscale).mean()
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self.app.logger.debug(
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"Average brightness of the image : " + str(avg_brightness)
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with Image.open(path) as img:
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# Preserve aspect ratio while fitting within the maximum dimensions.
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img.thumbnail(
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(max_width, max_height),
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Image.Resampling.LANCZOS,
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)
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grayscale = img.convert("L")
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avg_brightness = np.asarray(grayscale, dtype=np.float32).mean()
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self.app.logger.debug(
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"Average brightness of the image: %.2f", avg_brightness
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)
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# Dynamically compute brightness factor if too dark
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if avg_brightness < brightness_threshold:
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brightness_factor = (
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1 + (brightness_threshold - avg_brightness) / brightness_threshold
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)
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brightness_factor = min(
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max(brightness_factor, 1.1), 2.5
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) # Clamp between 1.1 and 2.5
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self.app.logger.debug(
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f"Image too dark, increasing brightness by a factor of {brightness_factor:.2f}"
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max(
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1 + (brightness_threshold - avg_brightness)
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/ brightness_threshold,
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1.1,
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),
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2.5,
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)
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self.app.logger.debug(
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"Image is dark; increasing brightness by %.2f",
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brightness_factor,
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)
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grayscale = ImageEnhance.Brightness(grayscale).enhance(
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brightness_factor
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)
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enhancer = ImageEnhance.Brightness(grayscale)
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grayscale = enhancer.enhance(brightness_factor)
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# Computer current contrast of grayscale image
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contrast = np.clip(np.std(np.array(grayscale)), 0, 255)
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self.app.logger.debug("Standard deviation of the contrast : %s", contrast)
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# # Enhance contrast
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contrast_enhancer = ImageEnhance.Contrast(grayscale)
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original_img = contrast_enhancer.enhance(contrast_factor)
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contrast = float(np.asarray(grayscale, dtype=np.float32).std())
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self.app.logger.debug("Grayscale standard deviation: %.2f", contrast)
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# Save the enhanced result.
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processed = ImageEnhance.Contrast(grayscale).enhance(contrast_factor)
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# Convert to JPEG and save
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jpeg_path = os.path.splitext(path)[0] + "_processed.jpg"
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grayscale.save(jpeg_path, format="JPEG", quality=95, optimize=True)
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self.app.logger.debug("Processed and saved image.")
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processed.save(jpeg_path, format="JPEG", quality=95, optimize=True)
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self.app.logger.debug("Processed and saved image: %s", jpeg_path)
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return jpeg_path
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def text_to_image(
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text,
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width=400,
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font_path="src/static/font/MonospaceTypewriter.ttf",
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font_size=24,
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padding=10,
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line_spacing=4,
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background="white",
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fill="black",
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output_dir="src/static/uploads",
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):
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"""Converts a string to an image"""
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font = ImageFont.truetype(font_path, font_size)
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# Measure and wrap text by pixel width.
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measure_img = Image.new("RGB", (1, 1))
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draw = ImageDraw.Draw(measure_img)
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max_text_width = width - 2 * padding
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if max_text_width <= 0:
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raise ValueError("width must be greater than twice the padding")
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lines = []
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for paragraph in text.splitlines() or [""]:
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words = paragraph.split()
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if not words:
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lines.append("")
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continue
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line = ""
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for word in words:
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candidate = f"{line} {word}".strip()
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if draw.textbbox((0, 0), candidate, font=font)[2] <= max_text_width:
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line = candidate
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continue
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if line:
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lines.append(line)
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# Split a word that is wider than the available width.
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line = ""
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piece = ""
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for char in word:
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if piece and draw.textbbox((0, 0), piece + char, font=font)[2] > max_text_width:
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lines.append(piece)
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piece = char
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else:
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piece += char
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line = piece
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if line:
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lines.append(line)
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if not lines:
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lines = [""]
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ascent, descent = font.getmetrics()
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line_height = ascent + descent
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height = (
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2 * padding
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+ len(lines) * line_height
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+ (len(lines) - 1) * line_spacing
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)
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image = Image.new("RGB", (width, height), background)
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draw = ImageDraw.Draw(image)
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y = padding
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for line in lines:
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draw.text((padding, y), line, font=font, fill=fill)
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y += line_height + line_spacing
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upload_dir = Path(output_dir)
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upload_dir.mkdir(parents=True, exist_ok=True)
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image_path = upload_dir / f"{uuid4().hex}.png"
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image.save(image_path, format="PNG")
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return str(image_path)
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