using Spire.Pdf;
using System.Drawing;

namespace PDFtoImage1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化一个PdfDocument类实例,并加载PDF文档
            PdfDocument doc = new PdfDocument();
            doc.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.pdf");

            //遍历PDF每一页
            for (int i = 0; i < doc.Pages.Count; i++)
            {
                //将PDF页转换成Bitmap图形
                System.Drawing.Image bmp = doc.SaveAsImage(i);

                //将Bitmap图形保存为Png格式的图片
                string fileName = string.Format("Page-{0}.png", i + 1);
                bmp.Save(fileName, System.Drawing.Imaging.ImageFormat.Png);
            }
        }
    }
}

using System;
using System.Drawing;
using System.Drawing.Imaging;
using Spire.Pdf;

namespace SavePdfAsTiff
{
    class Program
    {
        static void Main(string[] args)
        {
            //创建一个PdfDocument类对象，并加载PDF文档
            PdfDocument document = new PdfDocument();
            document.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.pdf");

            //调用方法SaveAsImage()将PDF文档保存为tiff格式
            JoinTiffImages(SaveAsImage(document), "result.tiff", EncoderValue.CompressionLZW);
            System.Diagnostics.Process.Start("result.tiff");
        }
        //自定义方法SaveAsImage()将PDF文档保存图像文件
        private static Image[] SaveAsImage(PdfDocument document)
        {
            Image[] images = new Image[document.Pages.Count];
            for (int i = 0; i < document.Pages.Count; i++)
            {
                images[i] = document.SaveAsImage(i);
            }
            return images;
        }

        private static ImageCodecInfo GetEncoderInfo(string mimeType)
        {
            ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
            for (int j = 0; j < encoders.Length; j++)
            {
                if (encoders[j].MimeType == mimeType)
                    return encoders[j];
            }
            throw new Exception(mimeType + " mime type not found in ImageCodecInfo");
        }
        //自定义JoinTiffImages()方法，使用指定编码器和图像编码器参数将图像从pdf页面保存到tiff图像类型，。
        public static void JoinTiffImages(Image[] images, string outFile, EncoderValue compressEncoder)
        {
            
            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);
            Image pages = images[0];
            int frame = 0;
            ImageCodecInfo info = GetEncoderInfo("image/tiff");
            foreach (Image img in images)
            {
                if (frame == 0)
                {
                    pages = img;
                    
                    pages.Save(outFile, info, ep);
                }

                else
                {
                    
                    ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.FrameDimensionPage);

                    pages.SaveAdd(img, ep);
                }
                if (frame == images.Length - 1)
                {
                    
                    ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.Flush);
                    pages.SaveAdd(ep);
                }
                frame++;
            }
        }
    }
}

using Spire.Pdf;
using System.Drawing;
using System.Drawing.Imaging;

namespace PDFtoImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //实例化一个PdfDocument类对象，并加载PDF文档
            PdfDocument doc = new PdfDocument();
            doc.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.pdf");

            //调用方法SaveAsImage()将PDF第二页保存为Bmp格式
            Image bmp = doc.SaveAsImage(1);
            //调用另一个SaveAsImage()方法，并将指定页面保存保存为Emf、Png      
            Image emf = doc.SaveAsImage(0, Spire.Pdf.Graphics.PdfImageType.Metafile);
            Image zoomImg = new Bitmap((int)(emf.Size.Width * 2), (int)(emf.Size.Height * 2));
            using (Graphics g = Graphics.FromImage(zoomImg))
            {
                g.ScaleTransform(2.0f, 2.0f);
                g.DrawImage(emf, new Rectangle(new Point(0, 0), emf.Size), new Rectangle(new Point(0, 0), emf.Size), GraphicsUnit.Pixel);
            }

            //命名保存的文件并打开
            bmp.Save("convertToBmp.bmp", ImageFormat.Bmp);
            System.Diagnostics.Process.Start("convertToBmp.bmp");
            emf.Save("convertToEmf.emf", ImageFormat.Emf);
            System.Diagnostics.Process.Start("convertToEmf.emf");
            zoomImg.Save("convertToZoom.png", ImageFormat.Png);
            System.Diagnostics.Process.Start("convertToZoom.png");
        }
    }
}