PDF Image converter for PB

PDF to Image Converter .NET Library For PowerBuilder

This is a .NET library that converts PDF files to PNG images while maintaining the original PDF dimensions.
The library is specifically designed to be used with PowerBuilder applications.
but other COM or anyway to invoke .NET(C#) DLL invoking way can works

Features

• Convert PDF files to PNG images
• Maintains original PDF dimensions
• Supports multi-page PDFs
• Configurable DPI settings
• COM-visible for use in PowerBuilder

Requirements

• .NET Framework 4.8.1 SDK for Development with build tool(select 1 of 2 options)
  • Visual Studio 2019 or later for building the library
  • .NET 8 SDK for building the library
• PowerBuilder 2019 R3 or later

Building the Library

1. Open the solution in Visual Studio
2. Build the solution in Release mode
3. if you want to build with dotnet cli(cause of not having visual studio)

   dotnet build PdfToImageConverter.csproj --configuration Release

Usage in PowerBuilder

1. Use PowerBuilder\’s \”.NET DLL Importer\” tool to import the assembly:

   • Open your PowerBuilder project
   • Select Tools → \”.NET DLL Importer\”
   • Browse to and select \”PdfToImageConverter.dll\”
     • Un-Zip release assets and select \”PdfToImageConverter.dll\”
     • Asset name is \”PdfToImageConverter-Full.zip\”
   • Generate the proxy object

2. Create an instance of the converter:

   nvo_pdfconverter lnvo_pdfconverter // if you use other name for the proxy object need to change the name in the code
   lnvo_pdfconverter = Create nvo_pdfconverter 

   but PB IDE automatic created proxy object name and function name shown as readme example

3. Convert PDF to PNG:

   string ls_result
   ls_result = lnvo_pdfconverter.of_convertpdftoimage(\"C:\\input.pdf\", \"C:\\output.png\", 300)
   
   if Left(ls_result, 7) = \"SUCCESS\" then
       MessageBox(\"Success\", ls_result)
   else
       MessageBox(\"Error\", ls_result)
   end if

4. Convert PDF to PNG with page names:

   string ls_result
   string ls_page_names[]
   ls_page_names[1] = \"Apple\"
   ls_page_names[2] = \"Banana\"
   ls_result = lnvo_pdfconverter.of_ConvertPdfToImageWithPageNames(\"C:\\input.pdf\", \"C:\\output.png\", 300, 2, ls_page_names)

5. Convert PDF to PNG with page names and custom output paths:

   string ls_result
   string ls_page_names[]
   string ls_output_paths[]
   ls_page_names[1] = \"Apple\"
   ls_page_names[2] = \"Banana\"
   ls_output_paths[1] = \"C:\\output\\folder1\"
   ls_output_paths[2] = \"C:\\output\\folder2\"
   ls_result = lnvo_pdfconverter.of_ConvertPdfToImageWithPageNamesAndOutputPaths(\"C:\\input.pdf\", \"C:\\output.png\", 300, 2, ls_page_names, ls_output_paths)

Parameters

• pdfPath: Full path to the input PDF file
• outputPath: Full path for the output PNG file
• dpi: Optional. DPI value for the output image (default: 300)

for ConvertPdfToImageWithPageNames method required some additional parameters:

• totalPagesNumber: Total number of pages in the PDF
• pageNames: Array of page names for the output images

for ConvertPdfToImageWithPageNamesAndOutputPaths method required these parameters:

• outputPaths: Array of output directory names for each page
• totalPagesNumber: Total number of pages in the PDF
• pageNames: Array of page names for the output images

Multi-page PDFs

When converting multi-page PDFs, the library will automatically append page numbers to the output filename:

• Single page: output.png
• Multi-page: output_page1.png, output_page2.png, etc.

If you want to use your own page names, you can use ConvertPdfToImageWithPageNames method.

• Ensure the totalPagesNumber is correct
• Ensure the pageNames array is the same size as the number of pages in the PDF
• then you got specific page names for each page like
  • Apple.png
  • Banana.png

If you want to specify custom output paths for each page, you can use ConvertPdfToImageWithPageNamesAndOutputPaths method.

• Ensure the outputPaths array contains valid directory paths for each page
• Ensure the pageNames array contains the desired filenames for each page
• then you got specific page names in specific folders like
  • C:\\output\\folder1\\Apple.png
  • C:\\output\\folder2\\Banana.png

Error Handling

The conversion method returns a string starting with either \”SUCCESS\” or \”ERROR\” followed by additional details. Make sure to handle both cases in your PowerBuilder code as shown in the usage example above.

Acknowledgements

• PDFtoImage for the PDF conversion library

Certainly! Here’s a COM-based usage example you can add to your README for users who want to use the PDF-Image Converter .NET DLL via COM (e.g., from VBScript, VBA, or other COM-aware environments).

Usage via COM (VBScript Example)

If you want to use the PDF-Image Converter library from a COM-based language (like VBScript, VBA, or classic ASP), make sure the DLL is registered as a COM-visible assembly.
You must register the DLL using regasm.exe and ensure all dependencies are available.

1. Register the DLL for COM

Open a command prompt as Administrator and run:

regasm PdfToImageConverter.dll /codebase

If you need to create a type library (.tlb):

regasm PdfToImageConverter.dll /codebase /tlb:PdfToImageConverter.tlb

Note: On 64-bit Windows, use the 64-bit regasm.exe for 64-bit clients, and the 32-bit version for 32-bit clients.

2. Example Usage in VBScript

Create a file named convert_pdf.vbs with the following contents:

\' Create the COM object
Set converter = CreateObject(\"PdfToImageConverter.PdfConverter\")

\' Convert a PDF to PNG
pdfPath = \"C:\\input.pdf\"
outputPath = \"C:\\output.png\"
dpi = 300

result = converter.ConvertPdfToImage(pdfPath, outputPath, dpi)

If Left(result, 7) = \"SUCCESS\" Then
    MsgBox \"Success: \" & result
Else
    MsgBox \"Error: \" & result
End If

3. Example Usage in VBA (e.g., Excel Macro)

Sub ConvertPDF()
    Dim converter As Object
    Set converter = CreateObject(\"PdfToImageConverter.PdfConverter\")
    
    Dim pdfPath As String
    Dim outputPath As String
    Dim dpi As Integer
    Dim result As String

    pdfPath = \"C:\\input.pdf\"
    outputPath = \"C:\\output.png\"
    dpi = 300

    result = converter.ConvertPdfToImage(pdfPath, outputPath, dpi)

    If Left(result, 7) = \"SUCCESS\" Then
        MsgBox \"Success: \" & result
    Else
        MsgBox \"Error: \" & result
    End If
End Sub

4. Notes

• The ProgID/class name (PdfToImageConverter.PdfConverter) may differ depending on your assembly’s namespace and class.
  Check your DLL\’s exposed class name or use OLE/COM Object Viewer to confirm.
• You must ensure the assembly is registered as COM visible and all dependencies are present.
• For advanced functions (like page names or custom output paths), you may need to pass arrays.
  COM clients like VBScript may not support passing arrays easily—consider using PowerBuilder or .NET clients for those features.

Would you like a sample for another COM-capable language or more details on DLL registration?