using Ghostscript.NET.Rasterizer;
using Ghostscript.NET;
using System.Collections.Generic;
using System.Drawing.Imaging;
using System.IO;
using System;
using System.Runtime.Remoting.Channels;
using System.Web;

namespace CommonHelper
{
    public static class PdfHelper
    {
        /// <summary>
        /// pdf转图片
        /// </summary>
        /// <param name="inputPdfPath">pdf路径，尽量避免中文</param>
        /// <returns></returns>
        public static IEnumerable<string> Pdf2Imgs(string inputPdfPath)
        {
            int desired_dpi = 96;

            var pdfName = Path.GetFileNameWithoutExtension(inputPdfPath);
            string outputPath = HttpContext.Current.Server.MapPath("~/CachePdfImages");
            Directory.CreateDirectory(outputPath);

            var dllPath = HttpContext.Current.Server.MapPath("~/Depends/gsdll64.dll");
#if DEBUG
            dllPath = HttpContext.Current.Server.MapPath("~/bin/Depends/gsdll64.dll");
#endif
            GhostscriptVersionInfo gvi = new GhostscriptVersionInfo(dllPath);

            using (var rasterizer = new GhostscriptRasterizer())
            {
                rasterizer.Open(inputPdfPath, gvi, false);

                for (var pageNumber = 1; pageNumber <= rasterizer.PageCount; pageNumber++)
                {
                    var pageFilePath = Path.Combine(outputPath, string.Format("p{0}_{1}_{2}.png", pageNumber,pdfName,DateTime.Now.ToString("HHmmssfff")));

                    var img = rasterizer.GetPage(desired_dpi, pageNumber);
                    img.Save(pageFilePath, ImageFormat.Png);
                    yield return pageFilePath;

                }
            }

        }
    }
}