Soluzione C# per la conversione da PDF a immagine

PM> Install-Package Spire.PDF

using Spire.Pdf;
    using Spire.Pdf.Graphics;
    using System.Drawing;
    using System.Drawing.Imaging;
    
    namespace PDFtoImage
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance
                PdfDocument pdf = new PdfDocument();
    
                //Load a sample PDF file
                pdf.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");
    
                //Convert the first page to an image and set the image Dpi
                Image image = pdf.SaveAsImage(0, PdfImageType.Bitmap, 500, 500);
    
                //Save images as JPG format to a specified folder 
                image.Save("C:\\Users\\Administrator\\Desktop\\Image\\ToImage.jpg", ImageFormat.Jpeg);
    
                //Close the document
                pdf.Close();
            }
        }
    }

using Spire.Pdf;
    
    namespace PDFtoSVG
    {
        class Program
        {
            static void Main(string[] args)
            {
                //Create a PdfDocument instance
                PdfDocument pdf = new PdfDocument();
    
                //Load a sample PDF file
                pdf.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");
    
                //Convert the first page to SVG
                pdf.SaveToFile("C:\\Users\\Administrator\\Desktop\\Image\\ToImage.svg", 0, 0, FileFormat.SVG);
    
                //Close the document
                pdf.Close();
            }
        }
    }

using System;
    using System.Drawing;
    using System.Drawing.Imaging;
    using Spire.Pdf;
    namespace SavePdfAsTiff
    {
        class Program
        {
            static void Main(string[] args)
            {
                // Create a PdfDocument instance
                PdfDocument pdf = new PdfDocument();
    
                // Load the PDF file
                pdf.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");
    
                // Convert PDF pages to images and save them as an image array
                Image[] images = SaveAsImage(pdf);
    
                // Merge the converted TIFF images into a multi-page TIFF file
                JoinTiffImages(images, "C:\\Users\\Administrator\\Desktop\\Image\\ToImage.tiff", EncoderValue.CompressionLZW);
            }
    
            private static Image[] SaveAsImage(PdfDocument pdf)
            {
                // Create an image array with the size equal to the number of PDF pages
                Image[] images = new Image[pdf.Pages.Count];
    
                //Iterate through each page of PDF
                for (int i = 0; i < pdf.Pages.Count; i++)
                {
                    //Convert these pages to images 
                    images[i] = pdf.SaveAsImage(i);
                }
                return images;
            }
    
            private static ImageCodecInfo GetEncoderInfo(string mimeType)
            {
                // Get all available image encoders
                ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
                for (int j = 0; j < encoders.Length; j++)
                {
                    // Find the encoder that matches the specified mime type
                    if (encoders[j].MimeType == mimeType)
                        return encoders[j];
                }
                // An exception is thrown if no matching encoder is found
                throw new Exception(mimeType + " mime type not found in ImageCodecInfo");
            }
    
            public static void JoinTiffImages(Image[] images, string outFile, EncoderValue compressEncoder)
            {
                //Set the parameters of the image encoder
                Encoder enc = Encoder.SaveFlag;
                EncoderParameters ep = new EncoderParameters(2);
                ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.MultiFrame);
                ep.Param[1] = new EncoderParameter(Encoder.Compression, (long)compressEncoder);
    
                // Initialize the first image as the base for merging
                Image pages = images[0];
                int frame = 0;
    
                // Get the encoder information for TIFF format
                ImageCodecInfo info = GetEncoderInfo("image/tiff");
    
                // Iterate through each image
                foreach (Image img in images)
                {
                    if (frame == 0)
                    {
                        // If it's the first frame, set it as the current base image
                        pages = img;
    
                        // Save the first frame using the specified encoder parameters
                        pages.Save(outFile, info, ep);
                    }
                    else
                    {
                        // For intermediate frames, update the encoder parameter to indicate a new page
                        ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.FrameDimensionPage);
    
                        // Save the intermediate frame
                        pages.SaveAdd(img, ep);
                    }
                    if (frame == images.Length - 1)
                    {
                        // If it's the last frame, flush the encoder parameters to close the file
                        ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.Flush);
                        pages.SaveAdd(ep);
                    }
                    frame++;
                }
            }
        }
    }