C# / VB.NET在PDF中加盖骑缝章

骑缝章是用于往来业务合同，以确保合同真实、有效的印章加盖方法，是一种防范风险的重要方式。在程序中，可以通过使用工具来辅助加盖这种骑缝章。下面将通过C#和VB.NET代码示例介绍具体的操作方法。

工具/原料

Free Spire.PDF for .NET （免费版）

工具下载及dll引用

1、在E-iceblue中文官网下载并解压安装到本地指定路径，完成安装后，将安装路径下Bin文件夹下的Spire.Pdf.dll文件添加引用至VS程序。如下引用效果：

C# 示例

1、using System.Collectio艘绒庳焰ns.Generic;using System.Drawing;using Spire.Pdf;using Spire.Pdf.Graphics;namespace PagingSeal{ class Program { static void Main(string[] args) { //加载PDF测试文档 PdfDocument doc = new PdfDocument(); doc.LoadFromFile("test.pdf"); //获取分割后的印章图片 Image[] images = GetImage(doc.Pages.Count); float x = 0; float y = 0; PdfUnitConvertor convert = new PdfUnitConvertor(); PdfPageBase pageBase = null; //将图片绘制到PDF页面上的指定位置 for (int i = 0; i < doc.Pages.Count; i++) { pageBase = doc.Pages[i]; x = pageBase.Size.Width - convert.ConvertToPixels(images[i].Width, PdfGraphicsUnit.Point) - 40; y = pageBase.Size.Height / 2; pageBase.Canvas.DrawImage(PdfImage.FromImage(images[i]), new PointF(x, y)); } //保存文档 doc.SaveToFile("Result.pdf"); System.Diagnostics.Process.Start("Result.pdf"); } //定义GetImage方法，根据PDF页数分割印章图片 static Image[] GetImage(int num) { List<Bitmap> lists = new List<Bitmap>(); Image image = Image.FromFile("seal.png"); int w = image.Width / num; Bitmap bitmap = null; for (int i = 0; i < num; i++) { bitmap = new Bitmap(w, image.Height); using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap)) { g.Clear(Color.White); Rectangle rect = new Rectangle(i * w, 0, w, image.Height); g.DrawImage(image, new Rectangle(0, 0, bitmap.Width, bitmap.Height), rect, GraphicsUnit.Pixel); } lists.Add(bitmap); } return lists.ToArray(); } }}

2、骑缝章添加效果：

VB.NET

1、Imports System.Collections.GenericImports System.DrawingImports Spire.PdfImports Spire.Pdf.Grap茑霁酌绡hicsNamespace PagingSeal Class Program Private Shared Sub Main(args As String()) '加载PDF测试文档 Dim doc As New PdfDocument() doc.LoadFromFile("test.pdf") '获取分割后的印章图片 Dim images As Image() = GetImage(doc.Pages.Count) Dim x As Single = 0 Dim y As Single = 0 Dim convert As New PdfUnitConvertor() Dim pageBase As PdfPageBase = Nothing '将图片绘制到PDF页面上的指定位置 For i As Integer = 0 To doc.Pages.Count - 1 pageBase = doc.Pages(i) x = pageBase.Size.Width - convert.ConvertToPixels(images(i).Width, PdfGraphicsUnit.Point) - 40 y = pageBase.Size.Height / 2 pageBase.Canvas.DrawImage(PdfImage.FromImage(images(i)), New PointF(x, y)) Next '保存文档 doc.SaveToFile("Result.pdf") System.Diagnostics.Process.Start("Result.pdf") End Sub '定义GetImage方法，根据PDF页数分割印章图片 Private Shared Function GetImage(num As Integer) As Image() Dim lists As New List(Of Bitmap)() Dim image__1 As Image = Image.FromFile("seal.png") Dim w As Integer = image__1.Width / num Dim bitmap As Bitmap = Nothing For i As Integer = 0 To num - 1 bitmap = New Bitmap(w, image__1.Height) Using g As System.Drawing.Graphics = System.Drawing.Graphics.FromImage(bitmap) g.Clear(Color.White) Dim rect As New Rectangle(i * w, 0, w, image__1.Height) g.DrawImage(image__1, New Rectangle(0, 0, bitmap.Width, bitmap.Height), rect, GraphicsUnit.Pixel) End Using lists.Add(bitmap) Next Return lists.ToArray() End Function End ClassEnd Namespace