如何使用 Java 缩小 PDF 文档中的内容

问题描述

如何使用 Java 缩小 PDF 文档中的内容。

解决方案

以下是使用 Java 缩小 PDF 文档中内容的程序。

import com.itextpdf.kernel.geom.AffineTransform; 
import com.itextpdf.kernel.geom.Rectangle; 

import com.itextpdf.kernel.pdf.PdfDocument; 
import com.itextpdf.kernel.pdf.PdfPage; 
import com.itextpdf.kernel.pdf.PdfReader; 
import com.itextpdf.kernel.pdf.PdfWriter; 
import com.itextpdf.kernel.pdf.canvas.PdfCanvas; 
import com.itextpdf.kernel.pdf.xobject.PdfFormXObject; 

import com.itextpdf.layout.Document;  

public class ShrinkPDF { 
   public static void main(String args[]) throws Exception { 

      //Creating a PdfWriter object 
      String dest = "C:/itextExamples/shrinking.pdf"; 
      PdfWriter writer = new PdfWriter(dest);      

      //Creating a PdfReader 
      String src = "C:/itextExamples/pdfWithImage.pdf"; 
      PdfReader reader = new PdfReader(src);        
      
      //Creating a PdfDocument objects 
      PdfDocument destpdf = new PdfDocument(writer);         
      PdfDocument srcPdf = new PdfDocument(reader);
      
      //Opening a page from the existing PDF 
      PdfPage origPage = srcPdf.getPage(1);       
      
      //Getting the page size 
      Rectangle orig = origPage.getPageSizeWithRotation(); 

      //Adding a page to destination Pdf 
      PdfPage page = destpdf.addNewPage();    

      //Scaling the image in a Pdf page 
      AffineTransform transformationMatrix = AffineTransform.getScaleInstance( 
         page.getPageSize().getWidth()/ orig.getWidth()/2, 
         page.getPageSize().getHeight()/ orig.getHeight()/2); 

      //Shrink original page content using transformation matrix 
      PdfCanvas canvas = new PdfCanvas(page);       
      canvas.concatMatrix(transformationMatrix); 

      //Add the object to the canvas 
      PdfFormXObject pageCopy = origPage.copyAsFormXObject(destpdf); 
      canvas.addXObject(pageCopy, 0, 0);        

      //Creating a Document object 
      Document doc = new Document(destpdf);         
      
      //Closing the document 
      doc.close();  
      System.out.println("Table created successfully.."); 
   }
}

输出