from PIL import Image , ImageEnhance from escpos.printer import Usb from picamera2 import Picamera2 import RPi.GPIO as GPIO import cv2 import numpy as np import os import signal import threading import time import io shots_dir = ' ./shots ' last_image = None os.makedirs(shots_dir, exist_ok= True ) camera_busy = False reprint_busy = False PRINTER_VENDOR_ID = 0x28e9 PRINTER_PRODUCT_ID = 0x0289 GPIO.cleanup() POWER_LED_PIN = 23 CAMERA_LED_PIN = 4 POWER_BUTTON_PIN = 22 CAMERA_BUTTON_PIN = 27 REPRINT_BUTTON_PIN = 26 GPIO.setmode(GPIO.BCM) GPIO.setup(POWER_LED_PIN, GPIO.OUT) GPIO.setup(CAMERA_LED_PIN, GPIO.OUT) GPIO.setup(POWER_BUTTON_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP) GPIO.setup(CAMERA_BUTTON_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP) GPIO.setup(REPRINT_BUTTON_PIN, GPIO.IN, pull_up_down=GPIO.PUD_UP) picam = Picamera2() camera_config = picam.create_still_configuration({ " size " : ( 2000 , 2000 )}) picam.align_configuration(camera_config) picam.configure(camera_config) picam.set_controls({ " FrameRate " : 1 }) picam.start() GPIO.output(CAMERA_LED_PIN, GPIO.LOW) GPIO.output(POWER_LED_PIN, GPIO.HIGH) def get_image_brightness (image): grayscale = image.convert( ' L ' ) histogram = grayscale.histogram() pixels = sum (histogram) brightness = sum (i * count for i, count in enumerate (histogram)) / pixels return brightness def histogram_equalization (image): img_gray = cv2.cvtColor(np.array(image), cv2.COLOR_RGB2GRAY) equalize_hist = cv2.equalizeHist(img_gray) equalized_image = Image.fromarray(equalize_hist) return equalized_image def gamma_correction (image, gamma= 0.7 ): img_array = np.array(image) / 255.0 corrected_array = np.power(img_array, gamma) corrected_image = Image.fromarray((corrected_array * 255 ).astype( ' uint8 ' )) return corrected_image def apply_clahe (image): img_gray = cv2.cvtColor(np.array(image), cv2.COLOR_RGB2GRAY) clahe = cv2.createCLAHE(clipLimit= 2.0 , tileGridSize=( 8 , 8 )) clahe_applied = clahe.apply(img_gray) equalized_image = Image.fromarray(clahe_applied) return equalized_image def contrast_stretch (image, low= 50 , high= 200 ): img_array = np.array(image) min_val = np.min(img_array) max_val = np.max(img_array) stretched = (img_array - min_val) * ((high - low) / (max_val - min_val)) + low stretched = np.clip(stretched, 0 , 255 ) stretched_image = Image.fromarray(stretched.astype( ' uint8 ' )) return stretched_image def camera_button_callback (channel): global last_image, camera_busy if camera_busy: return camera_busy = True def job (): global last_image, camera_busy try : GPIO.output(CAMERA_LED_PIN, GPIO.HIGH) timestamp = int (time.time()) filename = f " shots/image_{timestamp}.jpg " picam.capture_file(filename) GPIO.output(CAMERA_LED_PIN, GPIO.LOW) image = Image.open(filename) image = image.resize(( 576 , int (image.height * 576 / image.width))) brightness = get_image_brightness(image) if brightness < 60 : image = histogram_equalization(image) elif brightness < 90 : image = gamma_correction(image) elif brightness < 110 : image = apply_clahe(image) elif brightness < 130 : image = gamma_correction(image) else : image = contrast_stretch(image) converted_filename = f " shots/image_{timestamp}_converted.jpg " image.save(converted_filename) last_image = io.BytesIO() image.save(last_image, format= ' JPEG ' ) last_image.seek( 0 ) printer = Usb(PRINTER_VENDOR_ID, PRINTER_PRODUCT_ID) printer.image(converted_filename) printer.textln() printer.textln() printer.close() os.remove(converted_filename) except Exception as e: print(f " Error during capture/print: {e} " ) finally : camera_busy = False threading.Thread(target=job, daemon= True ).start() def power_button_callback (channel): os.system( ' shutdown now ' ) def reprint_button_callback (channel): global last_image, reprint_busy if reprint_busy: return reprint_busy = True def job (): global last_image, reprint_busy try : if last_image is None : return GPIO.output(CAMERA_LED_PIN, GPIO.HIGH) printer = Usb(PRINTER_VENDOR_ID, PRINTER_PRODUCT_ID) printer.image(Image.open(last_image)) printer.textln() printer.textln() printer.close() GPIO.output(CAMERA_LED_PIN, GPIO.LOW) finally : reprint_busy = False threading.Thread(target=job, daemon= True ).start() def cleanup (): GPIO.output(CAMERA_LED_PIN, GPIO.HIGH) GPIO.cleanup() picam.close() GPIO.add_event_detect(CAMERA_BUTTON_PIN, GPIO.FALLING, callback=camera_button_callback, bouncetime= 200 ) GPIO.add_event_detect(POWER_BUTTON_PIN, GPIO.FALLING, callback=power_button_callback, bouncetime= 200 ) GPIO.add_event_detect(REPRINT_BUTTON_PIN, GPIO.FALLING, callback=reprint_button_callback, bouncetime= 200 ) stop_event = threading.Event() def worker (): while not stop_event.is_set(): time.sleep( 1 ) def handle_signal (signal_num, frame): cleanup() stop_event.set() signal.signal(signal.SIGTERM, handle_signal) signal.signal(signal.SIGINT, handle_signal) thread = threading.Thread(target=worker, daemon= True ) thread.start() stop_event.wait()