PDF文档通常是不能编辑的,但有些时候需要在PDF文档中填写日期或签名之类,就需要在PDF有能编辑的文本域,本文介绍怎样用C#来实现这一功能。

环境

工具:VS2015
语言:C#
操作PDF类库:iTextSharp 5.5.10
生成的PDF预览的工具:Skim、福昕阅读器、Acrobat Reader

代码实现

获取文档的页数

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PdfReader reader = new PdfReader(@"C:\WorkSpace\1.pdf");
int count1 = reader.NumberOfPages;

创建文本域

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TextField fieldDate = new TextField(stamp.Writer, new iTextSharp.text.Rectangle(105, 100, 240, 125), "date1");
fieldDate.BackgroundColor = BaseColor.WHITE;
fieldDate.BorderWidth = 1;
fieldDate.BorderColor = BaseColor.BLACK;
fieldDate.BorderStyle = 4;
fieldDate.FontSize = 11f;

iTextSharp.text.Rectangle(105, 100, 240, 125) 用来设置文本域的位置,四个参数分别为:llx、lly、urx、ury:

  • llx 为Left ,lly 为Bottom,urx 为Right,ury 为Top
  • 其中:Width=Right - Left Heigth = Top - Bototom

创建文本

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Chunk cname = new Chunk("Date:", FontFactory.GetFont("Futura", 16f,new BaseColor(170,64,0)));
Phrase pname = new Phrase(cname);
PdfContentByte pdfover = stamp.GetOverContent(count);
ColumnText.ShowTextAligned(pdfover, Element.ALIGN_CENTER, pname, 400, 420, 0);

完整代码

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public static void AddTextField() { PdfReader reader = new PdfReader(@"C:\WorkSpace\1.pdf");
FileStream out1 = new FileStream(@"C:\WorkSpace\2.pdf", FileMode.Create, FileAccess.Write);
PdfStamper stamp = new PdfStamper(reader, out1);
int count1 = reader.NumberOfPages;
TextField fieldDate = new TextField(stamp.Writer, new iTextSharp.text.Rectangle(105, 100, 240, 125), "date");
fieldDate.BackgroundColor = BaseColor.WHITE;
fieldDate.BorderWidth = 1;
fieldDate.BorderColor = BaseColor.BLACK;
fieldDate.BorderStyle = 4;
fieldDate.FontSize = 11f;
TextField fieldSign = new TextField(stamp.Writer, new iTextSharp.text.Rectangle(430, 100, 530, 125), "sign");
fieldSign.BackgroundColor = BaseColor.WHITE;
fieldSign.BorderWidth = 1;
fieldSign.BorderColor = BaseColor.BLACK;
fieldSign.BorderStyle = 4;
fieldSign.FontSize = 11f;
Chunk cname = new Chunk("Date:", FontFactory.GetFont("Futura", 16f,new BaseColor(170,64,0)));
Chunk ctitle = new Chunk("User Sign:", FontFactory.GetFont("Futura", 16f, new BaseColor(0, 128, 128)));
Phrase pname = new Phrase(cname);
Phrase ptitle = new Phrase(ctitle);
//PdfContentBye类,用来设置图像和文本的绝对位置
PdfContentByte over = stamp.GetOverContent(count1);
ColumnText.ShowTextAligned(over, Element.ALIGN_CENTER, pname, 400, 420, 0);
ColumnText.ShowTextAligned(over, Element.ALIGN_CENTER, ptitle, 400, 350, 0);
stamp.AddAnnotation(fieldDate.GetTextField(), count);
stamp.AddAnnotation(fieldSign.GetTextField(), count);
stamp.FormFlattening = true;
stamp.Close();
}