How to Use Mono to Run ASP.NET C# Code in Ubuntu Linux

Mono is an open source implementation of Microsoft’s .NET Framework. It aims to help C# developers create cross-platform .NET applications. Although .NET Core is born for multiple platforms (Windows, Linux, and macOS), it is so far not a substitution of .NET framework. If you have an existing project written in .NET framework and want to run it in Linux, Mono is the most efficient way. In this post, I will share how to run an ASP.NET sample of Dynamic Web TWAIN using Mono in Ubuntu Linux.

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C# Camera API for Getting Video Frame

If you have a USB camera, how can you build a simple C# camera application on Windows 10? There are three options:  WIA (Windows Imaging Acquisition), DirectShow and MediaCapture. After trying some sample code that downloaded from CodeProject and GitHub, I got the conclusion: 1. WIA is not good because it does not support my webcam.  2. DirectShow can work well, but there is no C# API provided by Microsoft. You need to create a wrapper for C++ API. 3. MediaCapture class that designed for UWP apps provides C# APIs which provide low-level control over the capture pipeline and enable advanced capture scenarios. In this article, I want to share how to create a simple C# webcam app in which I can handle every preview frame myself.

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How to Bridge C Code to Create Swift Barcode Reader on Mac

Have you implemented any barcode reader software in Swift on Mac OS X? Since Dynamsoft released the 1D/2D barcode SDK for Mac, I was wondering how I can bridge the C dylib with Swift. Why Swift, not Objective-C? Because Apple is encouraging developers to migrate to the new programming language, it is important to master the new tool if you want to create more excellent apps for Mac and iOS in the future. Swift is totally new to me, and thus I spent two days googling relevant resources and finally figured out the solution.

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How to Make Java Barcode Reader with Dynamsoft Barcode SDK

Last week, Dynamsoft released Barcode Reader (DBR) SDK v2.0, which is available for Windows and Mac. The Windows installer contains Barcode libraries for ActiveX, C/C++, and .NET. If you are a Java developer, you have to use JNI to link native C/C++ libraries. In this tutorial, I’ll demonstrate how to invoke the native methods of Dynamsoft Barcode SDK via JNI to create a Java Barcode Reader.

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Wrapping C++ OCR Library in Java

Dynamsoft OCR SDK is totally implemented in C++, which means it is easy to be wrapped in high-level programming languages, such as C#, Java, Python and so on. As a proprietary development SDK, so far, only .NET OCR library is available for commercial use. Because some of developers and users are hoping that Dynamsoft could provide a Java OCR library, I wrapped the C++ OCR library for test. Anyone can feel free to use the sample, and I’d like to receive feedbacks from you.

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Barcode Generator with HTML5 WebSocket

Last week, I shared how to transmit an image between a WebSocket server and a Web client. Based on that, we can make a little bit of improvement. Today, I would like to share how to generate barcode on .Net server side and display it on web browser.

websocket barcode

Prerequisites

Remote Barcode Generator

  • In your WinForms project, add DynamicBarcode.dll and set its property Copy to Output Directory as Copy always. As so, the Dynamic .NET TWAIN component is able to automatically load the barcode library.

barcode library

  • Encode the received message, and draw generated barcode onto a background image:
            float scale = 3;
            short sImageIndex = 0;
            dynamicDotNetTwain.MaxImagesInBuffer = 1;
            bool isLoaded = dynamicDotNetTwain.LoadImage("test.png");
            dynamicDotNetTwain.AddBarcode(sImageIndex, Dynamsoft.DotNet.TWAIN.Enums.Barcode.BarcodeFormat.QR_CODE, message, "", 0, 0, scale);
  • Send image width, height and data to web client:
            Image img = dynamicDotNetTwain.GetImage(sImageIndex);

            ImageData imageData = load_image(img);
            session.Send(imageData.Width + "," + imageData.Height);
            session.Send(imageData.Data, 0, imageData.Data.Length);
            imageData = null;
  • Display the barcode image on JavaScript web client:
               ws.onmessage = function (evt) {
                    var data = evt.data;
                    if (!data)
                        return;

                    if (data instanceof ArrayBuffer) {
                        drawImage(evt.data);
                    }
                    else {
                        var len = data.length;
                        var index = data.indexOf(",");
                        var w = data.substring(0, index);
                        var h = data.substring(index + 1, len);
                        imageWidth = parseInt(w);
                        imageHeight = parseInt(h);
                    }
                };

Now, you can have fun with the remote barcode generator via all browsers (Chrome, Firefox, IE etc.) which support HTML5 WebSocket.

Source Code

WebSocketBarcodeGenerator