using O2S.Components.PDFRender4NET;

using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace Common.system
{
    /// <summary>
    /// 
    /// Class to convert a pdf to an image using GhostScript DLL
    /// Credit for this code go to:Rangel Avulso
    /// i only fix a little bug and refactor a little
    /// http://www.hrangel.com.br/index.php/2006/12/04/converter-pdf-para-imagem-jpeg-em-c/
    /// </summary>
    /// <seealso cref="http://www.hrangel.com.br/index.php/2006/12/04/converter-pdf-para-imagem-jpeg-em-c/"/>
    public class PdfTrunImage
    {
        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 List<string> ConvertPDF2Image(string pdfInputPath, string imageOutputPath,
            string imageName, int startPageNum, int endPageNum, ImageFormat imageFormat, Definition definition)
        {
            List<string> images = new List<string>();
            try
            {
                PDFFile pdfFile = PDFFile.Open(pdfInputPath);

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

                // validate pageNum
                if (startPageNum <= 0)
                {
                    startPageNum = 1;
                }

                if (endPageNum == 0 || endPageNum > pdfFile.PageCount)
                {
                    endPageNum = pdfFile.PageCount;
                }
                if (startPageNum > endPageNum)
                {
                    int tempPageNum = startPageNum;
                    startPageNum = endPageNum;
                    endPageNum = startPageNum;
                }

                // start to convert each page
                for (int i = startPageNum; i <= endPageNum; i++)
                {
                    Bitmap pageImage = pdfFile.GetPageImage(i - 1, 56 * (int)definition);
                    string imgPath = imageOutputPath + imageName + i.ToString() + "." + imageFormat.ToString();
                    pageImage.Save(imgPath, imageFormat);
                    images.Add(imgPath);
                    // 返回的图片绝对路径集合
                    pageImage.Dispose();
                }

                pdfFile.Dispose();
                return images;
            }
            catch (System.Exception ex)
            {
                LogHelper.WriteErrLog("PDF转图片" +
                    "【PdfTrunImage】" + ex.Message, ex);
                images = new List<string>();
                return images;
            }
        }
    }
}