แปลง PDF เป็น Image ใน C++

auto pres = System::MakeObject<Presentation>();
pres->get_Slides()->AddFromPdf(u"InputPDF.pdf");
for (int32_t i = 0; i < pres->get_Slides()->get_Count(); i++)
{
    // Control hidden slides (do not render hidden slides)
    if (pres->get_Slides()->idx_get(i)->get_Hidden())
    {
        continue;
    }
    
    // Convert slide to a Bitmap object
    System::SharedPtr<Bitmap> bmp = pres->get_Slides()->idx_get(i)->GetThumbnail(2.f, 2.f);

    // Create file name for an image
    System::String outputFilePath = Path::Combine(outputDir, System::String(u"Slide_") + i + u".png");
    
    // Save the image in PNG format
    bmp->Save(outputFilePath, ImageFormat::get_Png());
}