User Guide for C Language

In this guide, you will learn step by step on how to build a document normalization application with Dynamsoft Document Normalizer SDK using C language.

Requirements

• Operating System:
  • Windows 7, 8, 10, 11
  • Windows Server 2003, 2008, 2008 R2, 2012, 2016, 2019, 2022
  • Linux x64: Ubuntu 14.04.4+ LTS, Debian 8+, etc
• Developing Tool
  • Visual Studio 2008 or above
  • GCC 5.4+

Installation

If you haven’t downloaded the SDK yet, download the C/C++ Package now and unpack the package into the directory of your choice.

For this tutorial, we unpack it to [INSTALLATION FOLDER], change it to your unpacking path for the following content.

Build Your First Application

Let’s start by creating a console application which demonstrates how to use the minimum code to detect and normalize document from an image file.

You can download the entire source code from here.

Create a New Project

• For Windows

1. Open Visual Studio. Go to File > New > Project, create a new Empty Project and set Project name as DDNCSample.

2. Add a new source file named DDNCSample.c into the project.

• For Linux

1. Create a new source file named DDNCSample.c and place it into the folder [INSTALLATION FOLDER]/Samples.

Include the Library

1. Add headers and libs in DDNCSample.c.

    #include <stdio.h>
    #include "[INSTALLATION FOLDER]/Include/DynamsoftDocumentNormalizer.h"
    #if defined(_WIN64) || defined(_WIN32)
        #ifdef _WIN64
            #pragma comment(lib, "[INSTALLATION FOLDER]/Lib/Windows/x64/DynamsoftCorex64.lib")
            #pragma comment(lib, "[INSTALLATION FOLDER]/Lib/Windows/x64/DynamsoftDocumentNormalizerx64.lib")
        #else
            #pragma comment(lib, "[INSTALLATION FOLDER]/Lib/Windows/x86/DynamsoftCorex86.lib")
            #pragma comment(lib, "[INSTALLATION FOLDER]/Lib/Windows/x86/DynamsoftDocumentNormalizerx86.lib")
        #endif
    #endif
   

Initialize a Document Normalizer Instance

1. Initialize the license key.

    char szErrorMsg[256];
    DC_InitLicense("DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9", szErrorMsg, 256);
   

   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 Customer Portal.

2. Create an instance of Dynamsoft Document Normalizer.

    void *ddn = DDN_CreateInstance();
   

Detect and Save the Normalized Document

1. Apply normalization for an image file.

    int errorCode = 0;
    NormalizedImageResult* normalizedResult = NULL;
    errorCode = DDN_NormalizeFile(ddn, "[INSTALLATION FOLDER]/Images/sample-image.png", "", NULL, &normalizedResult);
    if(errorCode != DM_OK)
        printf("%s\n", DC_GetErrorString(errorCode));
   

   For the error handling mechanism, the SDK returns Error Code for each function and provides a function DC_GetErrorString to get the readable message. You should add codes for error handling based on your needs. Check out Error Code for full supported error codes.

2. Save the normalized result as an image file.

    if (normalizedResult != NULL)
    {
        DDN_SaveImageDataToFile(normalizedResult->image, "result-image.png");
    }
   

Release Allocated Memory

1. Release the allocated memory for the normalized result and instance.

    if (normalizedResult != NULL)
        DDN_FreeNormalizedImageResult(&normalizedResult);
    DDN_DestroyInstance(ddn);
   

Note:
Please change all [INSTALLATION FOLDER] in above code snippet to your unpacking path.

Build and Run the Project

• For Windows

1. In Visual Studio, set the solution to build as Release|x64.

2. Build the project to generate program DDNCSample.exe.

3. Copy ALL *.dll files under [INSTALLATION FOLDER]\Lib\Windows\x64 to the same folder as the DDNCSample.exe.

4. Run the program DDNCSample.exe.

The SDK supports both x86 and x64, please set the platform based on your needs.

• For Linux

1. Open a terminal and change to the target directory where DDNCSample.c located in. Build the sample:

    gcc -o DDNCSample DDNCSample.c -lDynamsoftCore -lDynamsoftDocumentNormalizer -L ../Lib/Linux -Wl,-rpath=../Lib/Linux
   

2. Run the program DDNCSample.

    ./DDNCSample
   

You can download the entire source code from here.