PDF另存为图片的一个方法

说明

有时需要把PDF的每一页另存为图片。用Devexpress可以很方便的完成这个功能。

窗体上放置一个PdfViewer。

然后循环每一页 for (int i = 1; i <= pdfViewer1.PageCount; i++)

调用 chg_pdf_to_bmp函数获得图片并保存

chg_pdf_to_bmp中调用了PdfViewer的CreateBitmap函数

全部代码

        private string pdf_fn = "";
        private void button1_Click(object sender, EventArgs e)
        {
            pdf_fn = textBox1.Text.Trim();
            if (! System.IO.File.Exists(pdf_fn))
                return;
            button1.Enabled = false;
            string dir = System.IO.Path.GetDirectoryName(pdf_fn) + @"\" + System.IO.Path.GetFileNameWithoutExtension(pdf_fn) + ".files";
            if (!System.IO.Directory.Exists(dir))
                System.IO.Directory.CreateDirectory(dir);
            pdfViewer1.LoadDocument(pdf_fn);
            progressBar1.Value = 0;
            progressBar1.Maximum = pdfViewer1.PageCount;
            Application.DoEvents();
            for (int i = 1; i <= pdfViewer1.PageCount; i++)
            {
                Bitmap bmp = chg_pdf_to_bmp(pdfViewer1,i);

                bmp.Save(dir+@"\"+i.ToString()+".jpg", ImageFormat.Jpeg ); 

                bmp.Dispose();
                progressBar1.Value = progressBar1.Value +1;
                Application.DoEvents();
            }
            MessageBox.Show("保存在"+ dir+"下");
            button1.Enabled = true;

        }

        private string pdf_fn = "";
        private void button1_Click(object sender, EventArgs e)
        {
            pdf_fn = textBox1.Text.Trim();
            if (! System.IO.File.Exists(pdf_fn))
                return;
            button1.Enabled = false;
            string dir = System.IO.Path.GetDirectoryName(pdf_fn) + @"\" + System.IO.Path.GetFileNameWithoutExtension(pdf_fn) + ".files";
            if (!System.IO.Directory.Exists(dir))
                System.IO.Directory.CreateDirectory(dir);
            pdfViewer1.LoadDocument(pdf_fn);
            progressBar1.Value = 0;
            progressBar1.Maximum = pdfViewer1.PageCount;
            Application.DoEvents();
            for (int i = 1; i <= pdfViewer1.PageCount; i++)
            {
                Bitmap bmp = chg_pdf_to_bmp(pdfViewer1,i);

                bmp.Save(dir+@"\"+i.ToString()+".jpg", ImageFormat.Jpeg ); 

                bmp.Dispose();
                progressBar1.Value = progressBar1.Value +1;
                Application.DoEvents();
            }
            MessageBox.Show("保存在"+ dir+"下");
            button1.Enabled = true;

        }

        public Bitmap chg_pdf_to_bmp(DevExpress.XtraPdfViewer.PdfViewer VW_PDF, int i_page_no, int max_w = 210 * 4 * 3)
        {
            DevExpress.Pdf.PdfDocument _pdf_document = null;
            VW_PDF.CurrentPageNumber = i_page_no;
            VW_PDF.Refresh();
            System.Reflection.PropertyInfo fiDocument = VW_PDF.GetType().GetProperty("Document", BindingFlags.Instance | BindingFlags.NonPublic);
            _pdf_document = fiDocument.GetValue(VW_PDF, null) as DevExpress.Pdf.PdfDocument;

            PdfPage pdfpage = _pdf_document.Pages[i_page_no - 1];
            SizeF page_sf = VW_PDF.GetPageSize(i_page_no);
            int pw = (int)(page_sf.Width / pdfpage.UserUnit * 500);
            int ph = (int)(page_sf.Height / pdfpage.UserUnit * 500);
            int bmp_w = pw;                                            //pw * 3 / 2;
            int bmp_h = ph;                                            //ph * 3 / 2; 
            if (bmp_w > max_w)
                bmp_w = max_w;
            Bitmap bmp = VW_PDF.CreateBitmap(i_page_no, bmp_w);
            return bmp;
        }

        public Bitmap chg_pdf_to_bmp(DevExpress.XtraPdfViewer.PdfViewer VW_PDF, int i_page_no, int max_w = 210 * 4 * 3)
        {
            DevExpress.Pdf.PdfDocument _pdf_document = null;
            VW_PDF.CurrentPageNumber = i_page_no;
            VW_PDF.Refresh();
            System.Reflection.PropertyInfo fiDocument = VW_PDF.GetType().GetProperty("Document", BindingFlags.Instance | BindingFlags.NonPublic);
            _pdf_document = fiDocument.GetValue(VW_PDF, null) as DevExpress.Pdf.PdfDocument;

            PdfPage pdfpage = _pdf_document.Pages[i_page_no - 1];
            SizeF page_sf = VW_PDF.GetPageSize(i_page_no);
            int pw = (int)(page_sf.Width / pdfpage.UserUnit * 500);
            int ph = (int)(page_sf.Height / pdfpage.UserUnit * 500);
            int bmp_w = pw;                                            //pw * 3 / 2;
            int bmp_h = ph;                                            //ph * 3 / 2; 
            if (bmp_w > max_w)
                bmp_w = max_w;
            Bitmap bmp = VW_PDF.CreateBitmap(i_page_no, bmp_w);
            return bmp;
        }