feat: issues/25

PDFiumSharp/PdfSupport.cs

@@ -0,0 +1,146 @@
+using PDFiumSharp.Types;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace PDFiumSharp
+{
+    /*
+     https://github.com/ArgusMagnus/PDFiumSharp/issues/25
+     */
+    public class PdfSupport
+    {
+        /// <summary>
+        /// Split pdf
+        /// </summary>
+        /// <param name="dest">The destination document which add the pages.</param>
+        /// <param name="pageNumber">from 1</param>
+        /// <returns></returns>
+        public static MemoryStream GetPDFPage(PdfDocument dest, int pageNumber)
+        {
+            var newDocument = PDFium.FPDF_CreateNewDocument();
+            if (PDFium.FPDF_ImportPages(newDocument, dest.Handle, pageNumber.ToString(), 0))
+            {
+                var ms = new MemoryStream();
+                {
+                    PDFium.FPDF_SaveAsCopy(newDocument, ms, SaveFlags.Incremental);
+                    PDFium.FPDF_CloseDocument(newDocument);
+                }
+                return ms;
+            }
+            return null;
+        }
+        /// <summary>
+        /// Split pdf
+        /// </summary>
+        /// <param name="dest">The destination document which add the pages.</param>
+        /// <param name="pagerange">
+        ///eg. "1,1,1,1"  4 1page
+        /// "1-3"      from 1 page to 3 
+        /// "1,3"      1page、3page 
+        /// </param>
+        /// <returns></returns>
+        public static MemoryStream GetPDFPage(PdfDocument dest, string pagerange)
+        {
+            var newDocument = PDFium.FPDF_CreateNewDocument();
+            if (PDFium.FPDF_ImportPages(newDocument, dest.Handle, pagerange, 0))
+            {
+                var ms = new MemoryStream();
+                {
+                    PDFium.FPDF_SaveAsCopy(newDocument, ms, SaveFlags.Incremental);
+                    PDFium.FPDF_CloseDocument(newDocument);
+                }
+                return ms;
+            }
+
+            return null;
+        }
+        /// <summary>
+        /// Merge pdf
+        /// </summary>
+        /// <param name="documents"></param>
+        /// <returns></returns>
+        public static MemoryStream MergePDF(params PdfDocument[] documents)
+        {
+            if (documents.Length == 0)
+            {
+                throw new ArgumentException("arg: documents not be 0 count");
+            }
+            var newDocument = PDFium.FPDF_CreateNewDocument();
+            var index = 0;
+            var res = false;
+            for (int i = 0; i < documents.Length; i++)
+            {
+                var dest_doc = documents[i];
+                if (dest_doc is PdfDocument dest)
+                {
+                    var pageCount = PDFium.FPDF_GetPageCount(dest.Handle);
+                    var page2 = $"{1}-{pageCount}";
+                    res = PDFium.FPDF_ImportPages(newDocument, dest.Handle, page2, index);
+                    index += pageCount;
+                }
+            }
+            if (!res)
+            {
+                return null;
+            }
+            var ms = new MemoryStream();
+            {
+                PDFium.FPDF_SaveAsCopy(newDocument, ms, SaveFlags.Incremental);
+                PDFium.FPDF_CloseDocument(newDocument);
+            }
+            return ms;
+        }
+
+        /// <summary>
+        /// Import some pages to a PDF document.
+        /// </summary>
+        /// <param name="dest_doc">The destination document which add the pages.</param>
+        /// <param name="src_doc">A document to be imported.</param>
+        /// <param name="index">The page index wanted to insert from.</param>
+        /// <returns></returns>
+        public static MemoryStream ImportPage(PdfDocument dest, PdfDocument src, int index)
+        {
+            var pageCount = PDFium.FPDF_GetPageCount(dest.Handle);
+            if (index < 0)
+                index = -1;
+            if (index >= pageCount)
+                index = pageCount;
+            var sheet = index + 1;
+            var newDocument = PDFium.FPDF_CreateNewDocument();
+            var preSheet = "";
+            var afterSheet = "";
+            bool res = false;
+            var iindex = 0;
+            if (sheet > 1)
+            {
+                preSheet = $"{1}-{sheet - 1}";
+                res = PDFium.FPDF_ImportPages(newDocument, dest.Handle, preSheet, iindex);
+                iindex += sheet - 1;
+            }
+            var currCount = PDFium.FPDF_GetPageCount(src.Handle);
+            var currSheet = $"{1}-{currCount}";
+            res = PDFium.FPDF_ImportPages(newDocument, src.Handle, currSheet, iindex);
+            iindex += currCount;
+            if (sheet < pageCount)
+            {
+                afterSheet = $"{sheet}-{pageCount}";
+                res = PDFium.FPDF_ImportPages(newDocument, dest.Handle, afterSheet, iindex);
+            }
+
+            if (res)
+            {
+                var ms = new MemoryStream();
+                {
+                    PDFium.FPDF_SaveAsCopy(newDocument, ms, SaveFlags.Incremental);
+                    PDFium.FPDF_CloseDocument(newDocument);
+                }
+                return ms;
+            }
+            return null;
+        }
+
+    }
+}

Samples/Test.Console/Program.cs

@@ -5,27 +5,59 @@
 using System.Threading.Tasks;
 using PDFiumSharp;
 using System.IO;
+using System.Security.Cryptography;
 
 namespace TestConsole
 {
-	class Program
-	{
-		static void Main(string[] args)
-		{
-			using (var doc = new PdfDocument("TestDoc.pdf", "password"))
-			{
-				int i = 0;
-				foreach (var page in doc.Pages)
-				{
-					using (var bitmap = new PDFiumBitmap((int)page.Width, (int)page.Height, true))
-					using (var stream = new FileStream($"{i++}.bmp", FileMode.Create))
-					{
-						page.Render(bitmap);
-						bitmap.Save(stream);
-					}
-				}
-			}
-			Console.ReadKey();
-		}
-	}
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            using (var doc = new PdfDocument("TestDoc.pdf", "password"))
+            {
+                int i = 0;
+                foreach (var page in doc.Pages)
+                {
+                    using (var bitmap = new PDFiumBitmap((int)page.Width, (int)page.Height, true))
+                    using (var stream = new FileStream($"{i++}.bmp", FileMode.Create))
+                    {
+                        page.Render(bitmap);
+                        bitmap.Save(stream);
+                    }
+                }
+            }
+            TestSplit();
+            TestMerge();
+            Console.ReadKey();
+        }
+
+        static void TestSplit()
+        {
+            using (var doc = new PdfDocument("TestDoc.pdf", "password"))
+            {
+                if (!Directory.Exists("TestDoc"))
+                {
+                    Directory.CreateDirectory("TestDoc");
+                }
+                for (global::System.Int32 i = 0; i < doc.Pages.Count; i++)
+                {
+                    var num = i + 1;
+                    using (var stream = PdfSupport.GetPDFPage(doc, num))
+                    {
+                        File.WriteAllBytes($@"TestDoc\{num}.pdf", stream.ToArray());
+                    }   
+                }
+            }
+        }
+
+        static void TestMerge()
+        {
+            var files = Directory.GetFiles("TestDoc", "*.pdf")?.ToList().
+                ConvertAll(file => new PdfDocument(file));
+            using (var stream = PdfSupport.MergePDF(files.ToArray()))
+            {
+                File.WriteAllBytes("TestDocNew.pdf", stream.ToArray());
+            }
+        }
+    }
 }