In some circumstances, you may need to change the page size of a PDF. For example, if you have a combined PDF file with pages of different sizes, you may want to resize the pages to the same size for easier reading and printing. In this article, we will introduce how to change the page size of a PDF file in Java using Spire.PDF for Java.
Install Spire.PDF for Java
First of all, you're required to add the Spire.Pdf.jar file as a dependency in your Java program. The JAR file can be downloaded from this link. If you use Maven, you can easily import the JAR file in your application by adding the following code to your project's pom.xml file.
<repositories>
<repository>
<id>com.e-iceblue</id>
<name>e-iceblue</name>
<url>https://repo.e-iceblue.com/nexus/content/groups/public/</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>e-iceblue</groupId>
<artifactId>spire.pdf</artifactId>
<version>10.4.4</version>
</dependency>
</dependencies>
Change PDF Page Size to a Standard Paper Size in Java
The way to change the page size of a PDF file is to create a new PDF file and add pages of the desired size to it, next, create templates from the pages in the original PDF file, then draw the templates onto the pages in the new PDF file. This process will preserve text, images, and other elements present in the original PDF.
Spire.PDF for Java supports a variety of standard paper sizes like letter, legal, A0, A1, A2, A3, A4, B0, B1, B2, B3, B4 and many more. The following steps show you how to change the page size of a PDF file to a standard paper size.
- Initialize a PdfDocument instance and load the original PDF file using PdfDocument.loadFromFile() method.
- Initialize another PdfDocument instance to create a new PDF file.
- Loop through the pages in the original PDF.
- Add pages of the desired size to the new PDF file using PdfDocument.getPages().add() method.
- Initialize a PdfTextLayout instance and set the text layout as one page using PdfTextLayout.setLayout() method.
- Create templates based on the pages in the original PDF using PdfPageBase.createTemplate() method.
- Draw the templates onto the pages in the new PDF file with the specified text layout using PdfTemplate.draw() method.
- Save the result file using PdfDocument.saveToFile() method.
- Java
import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.PdfPageSize;
import com.spire.pdf.graphics.*;
import java.awt.geom.Point2D;
public class ChangePageSizeToStandardPaperSize {
public static void main(String []args){
//Load the original PDF document
PdfDocument originPdf = new PdfDocument();
originPdf.loadFromFile("Sample.pdf");
//Create a new PDF document
PdfDocument newPdf = new PdfDocument();
//Loop through the pages in the original PDF
for(int i = 0; i< originPdf.getPages().getCount(); i++)
{
//Add pages of size A1 to the new PDF
PdfPageBase newPage = newPdf.getPages().add(PdfPageSize.A1, new PdfMargins((0)));
//Create a PdfTextLayout instance
PdfTextLayout layout = new PdfTextLayout();
//Set text layout as one page (if not set the content will not scale to fit page size)
layout.setLayout(PdfLayoutType.One_Page);
//Create templates based on the pages in the original PDF
PdfTemplate template = originPdf.getPages().get(i).createTemplate();
//Draw templates onto the pages in the new PDF
template.draw(newPage, new Point2D.Float(0,0), layout);
}
//Save the result document
newPdf.saveToFile("ChangePageSizeToA1.pdf");
}
}
Change PDF Page Size to a Custom Paper Size in Java
Spire.PDF for Java uses point (1/72 of an inch) as the unit of measure. If you want to change the page size of a PDF to a custom paper size in other units of measure like inches or millimeters, you can use the PdfUnitConvertor class to convert them to points.
The following steps show you how to change the page size of a PDF file to a custom paper size in inches:
- Initialize a PdfDocument instance and load the original PDF file using PdfDocument.loadFromFile() method.
- Initialize another PdfDocument instance to create a new PDF file.
- Initialize a PdfUnitConvertor instance, then convert the custom size in inches to points using PdfUnitConvertor.convertUnits() method.
- Initialize a Dimension2D instance from the custom size.
- Loop through the pages in the original PDF.
- Add pages of the custom size to the new PDF file using PdfDocument.getPages().add() method.
- Create a PdfTextLayout instance and set the text layout as one page using PdfTextLayout.setLayout() method.
- Create templates based on the pages in the original PDF using PdfPageBase.createTemplate() method.
- Draw the templates onto the pages in the new PDF file with the specified text layout using PdfTemplate.draw() method.
- Save the result file using PdfDocument.saveToFile() method.
- Java
import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.graphics.*;
import java.awt.*;
import java.awt.geom.Dimension2D;
import java.awt.geom.Point2D;
public class ChangePageSizeToCustomPaperSize {
public static void main(String []args){
//Load the original PDF document
PdfDocument originPdf = new PdfDocument();
originPdf.loadFromFile("Sample.pdf");
//Create a new PDF document
PdfDocument newPdf = new PdfDocument();
//Create a PdfUnitConvertor instance
PdfUnitConvertor unitCvtr = new PdfUnitConvertor();
//Convert the custom size in inches to points
float width = unitCvtr.convertUnits(6.5f, PdfGraphicsUnit.Inch, PdfGraphicsUnit.Point);
float height = unitCvtr.convertUnits(8.5f, PdfGraphicsUnit.Inch, PdfGraphicsUnit.Point);
//Create a Dimension2D instance from the custom size, then it will be used as the page size of the new PDF
Dimension2D size = new Dimension();
size.setSize(width, height);
//Loop through the pages in the original PDF
for(int i = 0; i< originPdf.getPages().getCount(); i++)
{
//Add pages of the custom size (6.5*8.5 inches) to the new PDF
PdfPageBase newPage = newPdf.getPages().add(size, new PdfMargins((0)));
//Create a PdfTextLayout instance
PdfTextLayout layout = new PdfTextLayout();
//Set text layout as one page (if not set the content will not scale to fit page size)
layout.setLayout(PdfLayoutType.One_Page);
//Create templates based on the pages in the original PDF
PdfTemplate template = originPdf.getPages().get(i).createTemplate();
//Draw templates onto the pages in the new PDF
template.draw(newPage, new Point2D.Float(0,0), layout);
}
//Save the result document
newPdf.saveToFile("ChangePageSizeToCustomSize.pdf");
}
}
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