app.py

#!/usr/bin/env python3

'''
Usage:
   app.py <license.txt>
'''

import sys
from PySide2.QtGui import QPixmap, QImage

from PySide2.QtWidgets import QApplication, QLabel, QPushButton, QVBoxLayout, QWidget, QFileDialog, QTextEdit, QMessageBox, QHBoxLayout
from PySide2.QtCore import QTimer

from barcode_manager import *
import os
import cv2


class UI_Window(QWidget):

    def __init__(self, license):
        QWidget.__init__(self)

        self.FRAME_WIDTH = 640
        self.FRAME_HEIGHT = 480
        self.WINDOW_WIDTH = 1280
        self.WINDOW_HEIGHT = 1000
        self._results = None
        # Initialize Dynamsoft Barcode Reader
        self._barcodeManager = BarcodeManager(license)

        # Initialize OpenCV camera
        self._cap = cv2.VideoCapture(0)
        # cap.set(5, 30)  #set FPS
        self._cap.set(cv2.CAP_PROP_FRAME_WIDTH, self.FRAME_WIDTH)
        self._cap.set(cv2.CAP_PROP_FRAME_HEIGHT, self.FRAME_HEIGHT)

        # The current path.
        self._path = os.path.dirname(os.path.realpath(__file__))

        # Create a timer.
        self.timer = QTimer()
        self.timer.timeout.connect(self.nextFrameUpdate)

        # Create a layout.
        layout = QVBoxLayout()

        # Add a button
        self.btn = QPushButton("Load an image")
        self.btn.clicked.connect(self.pickFile)
        layout.addWidget(self.btn)

        # Add a button
        button_layout = QHBoxLayout()

        btnCamera = QPushButton("Open camera")
        btnCamera.clicked.connect(self.openCamera)
        button_layout.addWidget(btnCamera)

        btnCamera = QPushButton("Stop camera")
        btnCamera.clicked.connect(self.stopCamera)
        button_layout.addWidget(btnCamera)

        layout.addLayout(button_layout)

        # Add a label
        self.label = QLabel()
        self.label.setFixedSize(self.WINDOW_WIDTH - 30, self.WINDOW_HEIGHT - 160)
        layout.addWidget(self.label)

        # Add a text area
        self.results = QTextEdit()
        layout.addWidget(self.results)

        # Set the layout
        self.setLayout(layout)
        self.setWindowTitle("Dynamsoft Barcode Reader")
        self.setFixedSize(self.WINDOW_WIDTH, self.WINDOW_HEIGHT)


    # https://stackoverflow.com/questions/1414781/prompt-on-exit-in-pyqt-application
    def closeEvent(self, event):
    
        msg = "Close the app?"
        reply = QMessageBox.question(self, 'Message', 
                        msg, QMessageBox.Yes, QMessageBox.No)

        if reply == QMessageBox.Yes:
            self.stopCamera()
            event.accept()
        else:
            event.ignore()

    def resizeImage(self, pixmap):
        lwidth = self.label.maximumWidth()
        pwidth = pixmap.width()
        lheight = self.label.maximumHeight()
        pheight = pixmap.height()

        wratio = pwidth * 1.0 / lwidth
        hratio = pheight * 1.0 / lheight

        if pwidth > lwidth or pheight > lheight:
            if wratio > hratio:
                lheight = pheight / wratio
            else:
                lwidth = pwidth / hratio

            scaled_pixmap = pixmap.scaled(lwidth, lheight)
            return scaled_pixmap
        else:
            return pixmap

    def showMessageBox(self, text):
        msgBox = QMessageBox()
        msgBox.setText(text)
        msgBox.exec_()

    def pickFile(self):
        self.stopCamera()
        # Load an image file.
        filename = QFileDialog.getOpenFileName(self, 'Open file',
                                               self._path, "Barcode images (*)")
        if filename is None or filename[0] == '':
            self.showMessageBox("No file selected")
            return

        # Read barcodes
        frame, results = self._barcodeManager.decode_file(filename[0])
        if frame is None:
            self.showMessageBox("Cannot decode " + filename[0])
            return
            
        self.showResults(frame, results)

    def openCamera(self):

        if not self._cap.isOpened(): 
            self.showMessageBox("Failed to open camera.")
            return

        self._barcodeManager.create_barcode_process()
        self.timer.start(1000./24)
    
    def stopCamera(self):
        self._barcodeManager.destroy_barcode_process()
        self.timer.stop()

    def showResults(self, frame, results):
        out = ''
        index = 0

        if results is not None and results[0] is not None:
            thickness = 2
            color = (0,255,0)
            out = 'Elapsed time: ' + "{:.2f}".format(results[1]) + 'ms\n\n'
            for result in results[0]:
                points = result.localization_result.localization_points
                out += "Index: " + str(index) + "\n"
                out += "Barcode format: " + result.barcode_format_string + '\n'
                out += "Barcode value: " + result.barcode_text + '\n'
                out += "Bounding box: " + str(points[0]) + ' ' + str(points[1]) + ' ' + str(points[2]) + ' ' + str(points[3]) + '\n'
                out += '-----------------------------------\n'
                index += 1

                cv2.line(frame, points[0], points[1], color, thickness)
                cv2.line(frame, points[1], points[2], color, thickness)
                cv2.line(frame, points[2], points[3], color, thickness)
                cv2.line(frame, points[3], points[0], color, thickness)
                cv2.putText(frame, result.barcode_text, points[0], cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0,0,255))

        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        image = QImage(frame, frame.shape[1], frame.shape[0], frame.strides[0], QImage.Format_RGB888)
        pixmap = QPixmap.fromImage(image)
        pixmap = self.resizeImage(pixmap)
        self.label.setPixmap(pixmap)
        self.results.setText(out)

    def nextFrameUpdate(self):
        ret, frame = self._cap.read()

        if not ret:
            self.showMessageBox('Failed to get camera frame!')
            return

        self._barcodeManager.append_frame(frame)
        self._results = self._barcodeManager.peek_results()

        self.showResults(frame, self._results)

def main():
    try:
        with open(sys.argv[1]) as f:
            license = f.read()
    except:
        license = ""

    app = QApplication(sys.argv)
    ex = UI_Window(license)
    ex.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    print(__doc__)
    main()