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Version: Version 1.3

Using other languages with the Pdftools SDK

Use the Pdftools SDK with Go, Python, and many other programming languages by binding the C API. The Pdftools SDK includes a powerful C API for high-performance applications, which can be used with a wide range of programming languages not directly supported by the Pdftools SDK.

Bind the C library and header files​

info

To bind the Pdftools SDK's C API to a different programming language, you require a compiled C library and header files. Download these files in the Pdftools SDK for C package.

The method for using the C library and header files differs slightly for each language.

Use the Pdftools SDK with Go​

Learn how to use the Go programming language with the Pdftools SDK's C API to convert a PDF document to an image in the following example.

note

These instructions explain the process by which you create a Go wrapper for the Pdftools SDK. For simplicity, some functionality such as error handling is not shown in the example code below.

The instructions assume that Go 1.6+ is installed on your system, and that the Go executable files are included in your path.

  1. Create a project directory named pdf2img.

  2. Extract the latest Pdftools SDK for C zip file into the pdf2img directory, then rename the extracted directory to PdftoolsSDK. The project structure looks like the following:

    pdf2img
    └── PdftoolsSDK
        ├── include
        └── lib

  3. Create a new file in the top-level project directory and name it pdf2img.go, and then add the following code inside it:

    package main

    // #cgo CFLAGS: -IPdftoolsSDK/include
    // #cgo LDFLAGS: -LPdftoolsSDK/lib/win-x64 -Wl,-rpath,PdftoolsSDK/lib/win-x64 -lPdfToolsSdk
    // #include "PdfTools_Platform.h"
    // #include "PdfTools_PdfTools.h"
    // #include "PdfTools_PdfToolsSys.h"
    // #include "PdfTools_PdfToolsPdf.h"
    // #include "PdfTools_PdfToolsImage.h"
    // #include "PdfTools_PdfToolsPdf2Image.h"
    // #include "PdfTools_PdfToolsPdf2ImageProfiles.h"
    // #include <stdlib.h>
    // #include <stdio.h>
    import "C"
    import (
      "os"
      "unsafe"
    )

    func main() {

      // Initialize the SDK
      C.PdfTools_Initialize()
      demokey := C.CString("<add-your-license-key-here>")
      C.PdfTools_Sdk_Initialize(demokey, nil)

      szInPath := C.CString(os.Args[1])
      szInParms := C.CString("rb")
      szOutPath := C.CString(os.Args[2])
      szOutParms := C.CString("wb+")
      var pInStream *C.FILE
      var pOutStream *C.FILE
      var pInDoc *C.TPdfToolsPdf_Document
      var pOutDoc *C.TPdfToolsImage_Document
      var pProfile *C.TPdfToolsPdf2ImageProfiles_Profile
      var pConverter *C.TPdfToolsPdf2Image_Converter

      // Open input document
      pInStream = C.fopen(szInPath, szInParms)
      var inDesc *C.TPdfToolsSys_StreamDescriptor
      inDesc = (*C.TPdfToolsSys_StreamDescriptor)(C.malloc(C.size_t(unsafe.Sizeof(*inDesc))))
      C.PdfToolsSysCreateFILEStreamDescriptor(inDesc, pInStream, 0)
      pInDoc = C.PdfToolsPdf_Document_Open(inDesc, C.CString(""))

      // Create output stream for writing
      pOutStream = C.fopen(szOutPath, szOutParms)
      var outDesc *C.TPdfToolsSys_StreamDescriptor
      outDesc = (*C.TPdfToolsSys_StreamDescriptor)(C.malloc(C.size_t(unsafe.Sizeof(*outDesc))))
      C.PdfToolsSysCreateFILEStreamDescriptor(outDesc, pOutStream, 0)

      // Create the profile that defines the conversion parameters.
      // The Archive profile converts PDF documents to TIFF images for archiving.
      pProfile = (*C.TPdfToolsPdf2ImageProfiles_Profile)(C.PdfToolsPdf2ImageProfiles_Archive_New())

      // Convert the PDF document to an image document
      pConverter = C.PdfToolsPdf2Image_Converter_New()
      pOutDoc =
        (*C.TPdfToolsImage_Document)(C.PdfToolsPdf2Image_Converter_ConvertDocument(pConverter, pInDoc, outDesc, pProfile))

      // Clean up resources
      if pOutDoc != nil {
        C.PdfToolsImage_Document_Close(pOutDoc)
      }
      C.PdfTools_Release(unsafe.Pointer(pConverter))
      C.PdfTools_Release(unsafe.Pointer(pProfile))
      if pOutStream != nil {
        C.fclose(pOutStream)
      }
      if pInDoc != nil {
        C.PdfToolsPdf_Document_Close(pInDoc)
      }
      if pInStream != nil {
        C.fclose(pInStream)
      }
      C.free(unsafe.Pointer(szInPath))
      C.free(unsafe.Pointer(szInParms))
      C.free(unsafe.Pointer(szOutPath))
      C.free(unsafe.Pointer(szOutParms))
      C.PdfTools_Uninitialize()
    }
    tip

    The output file is watermarked by default. If you have a valid license key, replace <add-your-license-key-here> with your Pdftools SDK license key.

  1. Open a terminal in the top-level project directory (~/pdf2img) and run:

    go build

  2. An executable file named pdf2img is created in the top-level project directory. Test the executable by running the command:

    pdf2img <path to input PDF file> <path to output image file>

    For example, place a PDF file named in.pdf in the top-level project directory and run:

    pdf2img in.pdf out.tif

    An output image file named out.tif is created in the top-level project directory.

Use the Pdftools SDK with Python​

tip

Download sample projects that show you how to use the Pdftools SDK with Python. See our Code samples page. The samples include: