using System;
using System.Drawing;
using System.Windows.Forms;
using System.IO;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;
using FileEventWatcher.Common;

namespace FileEventWatcher
{
    public class ConvertPDFtoImage
    {
        /// <summary>
        /// pdf转图片
        /// </summary>
        /// <param name="pdfFilePath">路径</param>
        /// <param name="beginPageNum">起始页</param>
        /// <param name="endPageNum">终了页</param>
        /// <param name="format">格式</param>
        public static void ConvertPdfToImage2(string pdfFilePath, int beginPageNum, int endPageNum, ImageFormat format)
        {
            //fileSystemWatcherFrm fw = new fileSystemWatcherFrm();
            //fw.FilePath();

            FilePath.CreateFilePath();

            for (int z = 0; z < Const.Zoom.Length; z++)
            {
                string imageDirectoryPath = Const.path[z];
                //Acrobat文档对象
                Acrobat.CAcroPDDoc pdfDoc = null;
                //页对象
                Acrobat.CAcroPDPage pdfPage = null;
                //用来描述页中一个矩形区域的对象
                Acrobat.CAcroRect pdfRect = null;
                //Size
                Acrobat.CAcroPoint pdfPoint = null;

                //生成操作Pdf文件的Com对象
                pdfDoc = (Acrobat.CAcroPDDoc)Microsoft.VisualBasic.Interaction.CreateObject("AcroExch.PDDoc", "");

                //检查输入参数
                if (!pdfDoc.Open(pdfFilePath)) 
                { 
                    throw new FileNotFoundException(string.Format("源文件{0}不存在！", pdfFilePath));
                }
                if (!Directory.Exists(imageDirectoryPath)) 
                { 
                    Directory.CreateDirectory(imageDirectoryPath); 
                }
                if (beginPageNum <= 0) 
                { 
                    beginPageNum = 1; 
                }
                if (endPageNum > pdfDoc.GetNumPages() || endPageNum <= 0)
                { 
                    endPageNum = pdfDoc.GetNumPages();
                }
                if (beginPageNum > endPageNum) 
                { 
                    throw new ArgumentException("参数\"beginPageNum\"必须小于\"endPageNum\"！");
                }
                if (format == null) 
                { 
                    format = ImageFormat.Png;
                }
                if (Const.Zoom[z] <= 0) 
                {
                    Const.Zoom[z] = 1;
                }

                //转换
                for (int i = beginPageNum; i <= endPageNum; i++)
                {
                    //取出当前页
                    pdfPage = (Acrobat.CAcroPDPage)pdfDoc.AcquirePage(i - 1);
                    //得到当前页的大小
                    pdfPoint = (Acrobat.CAcroPoint)pdfPage.GetSize();
                    //生成一个页的裁剪区矩形对象
                    pdfRect = (Acrobat.CAcroRect)Microsoft.VisualBasic.Interaction.CreateObject("AcroExch.Rect", "");

                    //计算当前页经缩放后的实际宽度和高度,zoom==1时，保持原比例大小
                    int imgWidth = (int)((double)pdfPoint.x * Const.Zoom[z]);
                    int imgHeight = (int)((double)pdfPoint.y * Const.Zoom[z]);

                    //设置裁剪矩形的大小为当前页的大小
                    pdfRect.Left = 0;
                    pdfRect.right = (short)imgWidth;
                    pdfRect.Top = 0;
                    pdfRect.bottom = (short)imgHeight;

                    #region old
                    //将当前页的裁剪区的内容编成图片后复制到剪贴板中
                    try
                    {
                        Clipboard.Clear();
                        pdfPage.CopyToClipboard(pdfRect, 0, 0, (short)(100 * Const.Zoom[z]));

                    }
                    catch (Exception e)
                    {
                        MessageBox.Show(e.Message.ToString());
                    }

                    IDataObject clipboardData = Clipboard.GetDataObject();

                    //检查剪贴板中的对象是否是图片，如果是图片则将其保存为指定格式的图片文件
                    if (clipboardData.GetDataPresent(DataFormats.Bitmap))
                    {

                        Bitmap pdfBitmap = (Bitmap)clipboardData.GetData(DataFormats.Bitmap);

                        pdfBitmap.Save(
                            System.IO.Path.Combine(imageDirectoryPath, i.ToString("0000") + "." + format.ToString()), format);

                        pdfBitmap.Dispose();

                        //Thread.Sleep(10);
                    }

                    //清空剪切板
                    Clipboard.Clear();
                    #endregion
                }

                //关闭和释放相关COM对象
                pdfDoc.Close();
                Marshal.ReleaseComObject(pdfRect);
                Marshal.ReleaseComObject(pdfPoint);
                Marshal.ReleaseComObject(pdfPage);
                Marshal.ReleaseComObject(pdfDoc);

                //会导致中断 why？
                //await Task.Delay(10);
            }
        }
    }
}