Pdf转成一张png或jpg图片

把Pdf文件转成一张png或jpg图片如下步骤：

1、下载第三方Pdf读取控件PDFFile.

2、如果想转成一张图片则用下面代码：

<pre name="code" class="csharp">using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;

namespace O2S.Components.PDFRender4NET.pdf2image
{
    public static class Program
    {
        public enum Definition
        {
            One = 1, Two = 2, Three = 3, Four = 4, Five = 5, Six = 6, Seven = 7, Eight = 8, Nine = 9, Ten = 10
        }

        /// <summary>
        /// 将PDF文档转换为图片的方法
        /// </summary>
        /// <param name="pdfInputPath">PDF文件路径</param>
        /// <param name="imageOutputPath">图片输出路径</param>
        /// <param name="imageName">生成图片的名字</param>
        /// <param name="startPageNum">从PDF文档的第几页开始转换</param>
        /// <param name="endPageNum">从PDF文档的第几页开始停止转换</param>
        /// <param name="imageFormat">设置所需图片格式</param>
        /// <param name="definition">设置图片的清晰度，数字越大越清晰</param>
        public static void ConvertPDF2Image(string pdfInputPath, string imageOutputPath,string imageName, ImageFormat imageFormat, Definition definition)
        {
            PDFFile pdfFile = null;
            try
            {
                pdfFile = PDFFile.Open(pdfInputPath);

                if (!Directory.Exists(imageOutputPath))
                {
                    Directory.CreateDirectory(imageOutputPath);
                }

                Bitmap bSize = pdfFile.GetPageImage(0, 50 * (int)definition);
                Bitmap bitMap = new Bitmap(bSize.Width, bSize.Height * (pdfFile.PageCount));
                //新建一个画板   
                Graphics gs = Graphics.FromImage(bitMap);
                //设置高质量插值法
                gs.InterpolationMode = InterpolationMode.High;
                //设置高质量,低速度呈现平滑程度
                gs.SmoothingMode = SmoothingMode.HighQuality;
                gs.Clear(Color.White);
                for (int i = 0; i < pdfFile.PageCount; i++)
                {
                    Bitmap bm = pdfFile.GetPageImage(i, 50 * (int)definition);
                    //在指定位置画图
                    gs.DrawImage(bm, new Point(0, i * bm.Height));

                    bm.Dispose();
                }

                bitMap.Save("E:\\pdf\\pdfImg\\5.jpg", imageFormat);
                gs.Dispose();
                pdfFile.Dispose();
            }
            catch (Exception ex)
            {
                pdfFile.Dispose();
                throw ex;
            }
        }

        public static void Main(string[] args)
        {
            ConvertPDF2Image("E:\\pdf\\1383812619357.pdf", "E:\\pdf\\pdfImg\\", "1384174318423", ImageFormat.Jpeg, Definition.Two);
        }

    }
}