How to Change PDF Backgrounds in Java: Add Background Colors and Images

<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>12.6.1</version>
    </dependency>
</dependencies>

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;

import java.awt.Color;

public class AddPdfBackgroundColor {

    public static void main(String[] args) {
        String inputPath = "input.pdf";
        String outputPath = "output-background-color.pdf";

        PdfDocument document = new PdfDocument();

        // Load the source PDF file.
        document.loadFromFile(inputPath);

        // Loop through all pages in the PDF document.
        for (int pageIndex = 0; pageIndex < document.getPages().getCount(); pageIndex++) {
            PdfPageBase page = document.getPages().get(pageIndex);

            // Set a light blue background color for the current page.
            page.setBackgroundColor(new Color(230, 240, 255));

            // Set the background opacity. A larger value makes the color more visible.
            page.setBackgroudOpacity(0.35f);
        }

        // Save the modified PDF as a new file to avoid overwriting the original one.
        document.saveToFile(outputPath);

        // Release PDF resources.
        document.close();
    }
}

// Use a very light background, suitable for text-heavy documents.
page.setBackgroudOpacity(0.15f);

// Use a stronger background effect, suitable for cover pages or section pages.
page.setBackgroudOpacity(0.5f);

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class AddPdfBackgroundImage {

    public static void main(String[] args) throws IOException {
        String inputPath = "input.pdf";
        String imagePath = "background.jpg";
        String outputPath = "output-background-image.pdf";

        PdfDocument document = new PdfDocument();

        // Load the PDF file that needs a background image.
        document.loadFromFile(inputPath);

        // Read the image that will be used as the page background.
        BufferedImage backgroundImage = ImageIO.read(new File(imagePath));

        // Apply the same background image to each page in the PDF.
        for (int pageIndex = 0; pageIndex < document.getPages().getCount(); pageIndex++) {
            PdfPageBase page = document.getPages().get(pageIndex);

            // Set the image as the background of the current page.
            page.setBackgroundImage(backgroundImage);

            // Adjust the image opacity so the original PDF content remains readable.
            page.setBackgroudOpacity(0.25f);
        }

        // Save the result as a new PDF file.
        document.saveToFile(outputPath);

        // Close the document to release resources.
        document.close();
    }
}

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;

import java.awt.Color;

public class AddBackgroundToFirstPage {

    public static void main(String[] args) {
        PdfDocument document = new PdfDocument();

        // Load the original PDF document.
        document.loadFromFile("input.pdf");

        // Make sure the document has at least one page before accessing the first page.
        if (document.getPages().getCount() > 0) {
            PdfPageBase firstPage = document.getPages().get(0);

            // Apply a warm background color to the first page.
            firstPage.setBackgroundColor(new Color(245, 238, 220));

            // Set the opacity of the background color.
            firstPage.setBackgroudOpacity(0.4f);
        }

        // Save the updated PDF as a separate file.
        document.saveToFile("output-first-page-background.pdf");

        // Release PDF resources.
        document.close();
    }
}

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;

import java.awt.Color;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

public class AddBackgroundToSelectedPages {

    public static void main(String[] args) {
        PdfDocument document = new PdfDocument();

        // Load the source PDF file.
        document.loadFromFile("input.pdf");

        // Define the page numbers that need a background.
        // Page numbers here start from 1, which is easier to match with what users see in a PDF reader.
        Set<Integer> targetPages = new HashSet<>(Arrays.asList(1, 3, 5));

        // Loop through all pages and apply the background only to selected pages.
        for (int pageIndex = 0; pageIndex < document.getPages().getCount(); pageIndex++) {
            int pageNumber = pageIndex + 1;

            // Skip pages that are not included in the target page list.
            if (!targetPages.contains(pageNumber)) {
                continue;
            }

            PdfPageBase page = document.getPages().get(pageIndex);

            // Set a light green background for the selected page.
            page.setBackgroundColor(new Color(240, 248, 240));

            // Control how visible the background color should be.
            page.setBackgroudOpacity(0.3f);
        }

        // Save the processed PDF document.
        document.saveToFile("output-selected-pages-background.pdf");

        // Close the document after saving.
        document.close();
    }
}

// Save the processed PDF to a new file instead of overwriting the source file.
document.saveToFile("new-file.pdf");

// Very light background effect.
page.setBackgroudOpacity(0.15f);

// Moderate background effect.
page.setBackgroudOpacity(0.25f);

// More visible background effect.
page.setBackgroudOpacity(0.35f);