PDF转图片

FreeSpire.Pdf 将PDF转图片

工作中遇到一个需求，要将PDF转成图片保存，就是干！！！然后找了一圈 nuget 包 基本上都是有水印的

在gitee上中到一个 只支持 x86 的 [pdf2image] (https://gitee.com/zendu/pdf2image) ，这个倒是没有水印，但是不能x64，不够完美，作为一个处女座的码农怎么能允许这种事情发生！！

于是继续去nuget继续寻找，终于 找到了 --- FreeSpire.Pdf (https://www.nuget.org/packages/FreeSpire.PDF)

然后代码很简单，直接上

using Spire.Pdf;
public class PdfExtendProvider
    {
        /// <summary>
        ///  pdf 文件 转换成图片
        /// </summary>
        /// <param name="pdfPath">pdf文件所在的物理路径（全路径，如：C:\Users\Administrator\Desktop\1234.pdf ）</param>
        /// <param name="IsOne">转换的pic是每一页一张图片，还是整个pdf一张图片，默认整个pdf一张图片</param>
        /// <param name="picPath">转换的pic存储的物理路径，默认和pdf文件同路径</param>
        /// <param name="picName">pic文件名前缀，默认和pdf文件同名</param>
        /// <param name="format">转换成图片的格式，默认jpg</param>
        /// <param name="picDpiX">图像水平方向上的dpi</param>
        /// <param name="picDpiY">图像垂直方向上的dpi</param>
        /// <param name="startIndex">pdf文件中要转换的起始页，默认从第一页开始</param>
        /// <param name="endIndex">pdf文件中要转换的终止页，默认到最后一页结束</param>
        /// <returns></returns>
        public Pdf2PicResult ConvertPdf2Pic(string pdfPath, string picPath = "", string picName = "", bool IsOne = true, int startIndex = 1, int endIndex = -1, int picDpiX = 500, int picDpiY = 500)
        {
            #region ================= 参数验证 ====================

            // PDF 路径的正则
            string pdfPattern = "^[C-Z]:\\\\([^\\\\?\\/\\*\\|<>:\"]+\\\\)*[^\\\\?\\/\\*\\|<>:\"]+\\.pdf$";
            Regex reg = new Regex(pdfPattern, RegexOptions.IgnoreCase);
            if (!reg.IsMatch(pdfPath))
            {
                throw new ArgumentException("pdfPath error");
            }
            // 文件是否存在
            if (!File.Exists(pdfPath))
            {
                throw new FileNotFoundException(pdfPath + " not found");
            }
            //打开PDF
            PdfDocument pdf = new PdfDocument();
            pdf.LoadFromFile(pdfPath);
            // 文件页数
            int pagecount = pdf.Pages.Count;
            if (pagecount <= 0)
            {
                throw new Exception(pdfPath + "pdf file page number must be greater than 0 ");
            }

            string[] array = pdfPath.Split('\\');
            string pdfNameWithExtension = array[array.Length - 1];
            // 文件名 
            if (string.IsNullOrEmpty(picName))
            {
                picName = pdfNameWithExtension.Split('.')[0];
            }
            // 存储路径
            if (string.IsNullOrEmpty(picPath))
            {
                picPath = pdfPath.Replace(pdfNameWithExtension, "");
            }
            string picPattern = @"^[a-zA-Z]:(((\\(?! )[^/:*?<>\""|\\]+)+\\?)|(\\)?)\s*$";
            Regex regex = new Regex(picPattern);
            if (!regex.IsMatch(picPath) || picPath.Trim().Length <= 0)
            {
                throw new ArgumentException("picPath error");
            }
            // x dpi
            if (picDpiX <= 0 || picDpiX > 1000)
            {
                throw new ArgumentException("picDpiX must be between 0 and 1000");
            }
            // y dpi
            if (picDpiY <= 0 || picDpiY > 1000)
            {
                throw new ArgumentException("picDpiY must be between 0 and 1000");
            }
            // 起始页
            if (startIndex <= 0)
            {
                throw new ArgumentException("startIndex must be greater than 0 ");
            }
            // 结束页
            if (endIndex == -1)
            {
                endIndex = pagecount;
            }
            if (endIndex < startIndex)
            {
                throw new ArgumentException("endIndex must be greater than startIndex");
            }
            #endregion

            Pdf2PicResult returnResult = new Pdf2PicResult()
            {
                IsSussess = false,
                PicPath = null,
                Message = "",
            };
            try
            {
                //  配置图片
                List<string> picSavePath = new List<string>();
                // 生成图片
                //遍历PDF每一页
                for (int i = 0; i < pagecount; i++)
                {
                    //将PDF页转换成Bitmap图形
                    Image bmp = pdf.SaveAsImage(i, picDpiX, picDpiY);
                    //将Bitmap图形保存为Jpg格式的图片
                    string fileName = string.Format(@"{0}{1}_{2}.jpg", picPath, picName, i + 1);
                    picSavePath.Add(fileName);
                    bmp.Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);
                }
                // 整个pdf一张图
                if (IsOne)
                {
                    string result = MergePic(picSavePath, picDpiX, picDpiY);

                    returnResult.PicPath = new List<string>() { result };
                }
                else
                {
                    returnResult.PicPath = picSavePath;
                }
                returnResult.IsSussess = true;
            }
            catch (Exception ex)
            {
                returnResult.IsSussess = false;
                returnResult.Message = ex.Message;
            }
            return returnResult;
        }

        private string MergePic(List<string> pathList, int picDpiX, int picDpiY, string picName = "")
        {
            if (pathList == null || pathList.Count <= 0)
            {
                throw new ArgumentException("pathList is null or Empty");
            }
            List<Image> imgList = new List<Image>();
            //最大宽度和高度
            int maxLength = 0, totalHegiht = 0;
            //循环遍历获取文件的最大宽度与总高度
            foreach (var item in pathList)
            {
                if (!File.Exists(item))
                {
                    throw new FileNotFoundException(item + "  is not found");
                }
                Image image = Image.FromStream(new System.IO.MemoryStream(File.ReadAllBytes(item)));
                imgList.Add(image);
                if (image.Width > maxLength)
                {
                    maxLength = image.Width;
                }
                totalHegiht += image.Height;
            }
            if (totalHegiht == 0 || maxLength == 0)
            {
                throw new ArgumentException("picture is null");
            }
            Bitmap map = new Bitmap(maxLength, totalHegiht);//定义画布
            map.SetResolution(picDpiX, picDpiY);// 设置 dpi
            Graphics graphics = Graphics.FromImage(map);//定义画笔
            graphics.Clear(Color.White);//把画布更改为白色
            int y = 0;//y轴坐标
            foreach (var item in imgList)
            {
                graphics.DrawImage(item, new Point(0, y));
                y += item.Height;
            }
            string savePath = "";
            if (string.IsNullOrEmpty(picName))
            {
                // 也可以用 正则 将‘_*.jpg’ 替换为 ‘.jpg’
                var list = pathList[0].Split('\\');
                string nameWithExtension = list[list.Length - 1];
                savePath = pathList[0].Replace(nameWithExtension, "");
                var tempName = nameWithExtension.Split('.')[0];
                var picNameArray = tempName.Split('_');
                string picNameTemp = "_" + picNameArray[picNameArray.Length - 1];
                picName = tempName.Replace(picNameTemp, "");
            }
            savePath = Path.Combine(savePath, picName + ".jpg");
            //把合并的图片进行保存为jpg格式
            map.Save(savePath, System.Drawing.Imaging.ImageFormat.Jpeg);
            return savePath;
        }
    }

    public class Pdf2PicResult
    {

        /// <summary>
        /// pdf每一页转换的图片的物理路径
        /// </summary>
        public List<string> PicPath { get; set; }
        /// <summary>
        /// 
        /// </summary>
        public string Message { set; get; }
        /// <summary>
        /// 
        /// </summary>
        public bool IsSussess { set; get; }
    }