Getting Started with Dynamsoft Barcode Reader SDK Python Edition

In this guide, you will learn step by step on how to build a barcode reading application with Dynamsoft Barcode Reader SDK using python.

Read more on Dynamsoft Barcode Reader Features

Getting Started with Dynamsoft Barcode Reader SDK Python Edition

System Requirements

To find out whether your environment is supported, please read the System Requirements.

Installation

Start terminal or command prompt to run the following command:

pip install dynamsoft_barcode_reader_bundle

Build Your First Application

Let’s start by creating a console application which demonstrates how to use the minimum code to read barcodes from an image file.

You can download the entire source code from here.

Create a New Project

Create a new source file named DBRPythonSample.py.

Include the Library

Import package dynamsoft_barcode_reader_bundle in the source file.

from dynamsoft_barcode_reader_bundle import *

Initialize the License Key

Add the following code inside the __main__ method to initialize the license for using the SDK in the application:

errorCode, errorMsg = LicenseManager.init_license("DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9")
if errorCode != EnumErrorCode.EC_OK and errorCode != EnumErrorCode.EC_LICENSE_CACHE_USED:
    print("License initialization failed: ErrorCode:", errorCode, ", ErrorString:", errorMsg)
else:
    # codes from following steps

The string “DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9” here is a free public trial license. Note that network connection is required for this license to work. When it expires, you can request a 30-day free trial license from the Customer Portal.

Create a CaptureVisionRouter Instance

cvr = CaptureVisionRouter()

Invoke the Barcode Capturing

result = cvr.capture("[PATH-TO-THE-IMAGE-FILE]", EnumPresetTemplate.PT_READ_BARCODES.value)

Please change the [PATH-TO-THE-IMAGE-FILE] to a real barcode image file path.

Filter and Get Barcode Details

if result.get_error_code() != EnumErrorCode.EC_OK:
    print("Error:", result.get_error_code(), result.get_error_string())
barcode_result = result.get_decoded_barcodes_result()
if barcode_result is None or barcode_result.get_items() == 0:
    print("No barcode detected.")
else:
    items = barcode_result.get_items()
    print("Decoded", len(items), "barcodes.")
    for index,item in enumerate(items):
        print("Result", index+1)
        print("Barcode Format:", item.get_format_string())
        print("Barcode Text:", item.get_text())

Build and Run the Project

Save the ``DBRPythonSample.py` file.
Start terminal or command prompt and change to the target directory where DBRPythonSample.py located in.
Run the command

python DBRPythonSample.py

You will see the output message in the console like

Decoded 2 barcodes
Result 1
Barcode Format: XXX
Barcode Text: XXX
Result 2
Barcode Format: XXX
Barcode Text: XXX

Process Multiple Images

If, instead of processing one single image, you need to process many images at once, you can follow these steps:

These steps follow the step Create a CaptureVisionRouter Instance mentioned above.

You can download the entire source code from here.

Create an ImageSource as the Input

An ImageSource is required when creating a multi-image processing application. You can either utilize ready-made image sources such as FileFetcher and DirectoryFetcher, or customize your own image source based on the base class ImageSourceAdapter.

In this sample, we will use the DirectoryFetcher to retrieve images from a local directory.

fetcher = DirectoryFetcher()
fetcher.set_directory("[THE DIRECTORY THAT HOLDS THE IMAGES]")

Please change the [THE DIRECTORY THAT HOLDS THE IMAGES] to full path of the directory holding barcode image files.

Implement a CapturedResultReceiver as the Output Listener

Create a class MyCapturedResultReceiver to implement the CapturedResultReceiver class, and get the barocde results in on_decoded_barcodes_received callback function.

class MyCapturedResultReceiver(CapturedResultReceiver):
    def __init__(self) -> None:
        super().__init__()
    def on_decoded_barcodes_received(self, result: "DecodedBarcodesResult") -> None:
        tag = result.get_original_image_tag()
        if isinstance(tag, FileImageTag):
            print("File:", tag.get_file_path())
        if result.get_error_code() != EnumErrorCode.EC_OK:
            print("Error:", result.get_error_string())
        else:
            items = result.get_items()
            print("Detected", len(items), "barcodes.")
            for index, item in enumerate(items):
                print("Result", index+1)
                print("Barcode Format:", item.get_format_string())
                print("Barcode Text:", item.get_text())

Handle Capture Stoppage by Implementing an ImageSource State Listener

Create a class MyImageSourceStateListener to implement the ImageSourceStateListener class, and call stop_capturing in on_image_source_state_received callback function when the state is ISS_EXHAUSTED.

class MyImageSourceStateListener(ImageSourceStateListener):
    def __init__(self, cvr:CaptureVisionRouter) -> None:
        super().__init__()
        self.cvr = cvr
    def on_image_source_state_received(self, state: int) -> None:
        if state == EnumImageSourceState.ISS_EXHAUSTED:
            if self.cvr != None:
                self.cvr.stop_capturing()

Register the Input, Output Listener and ImageSource State Listener to the CaptureVisionRouter Instance

cvr.set_input(fetcher)
receiver = MyCapturedResultReceiver()
cvr.add_result_receiver(receiver)
listener = MyImageSourceStateListener(cvr)
cvr.add_image_source_state_listener(listener)

Start the Capturing Process

Call the method start_capturing() to start processing all the images in the specified folder.

errorCode, errorMsg = cvr.start_capturing("", True)
if errorCode != EnumErrorCode.EC_OK:
    print("error:", errorMsg)

During the process, the callback function on_decoded_barcodes_received() is triggered each time processing of an image is finished. After all images are processed, the listener function on_image_source_state_received() will be triggered while the image source state is ISS_EXHAUSTED and the process is stopped with the method stop_capturing().

Build and Run the Project Again

Please refer to Build and Run the Project.