How do I rotate image in iText PDF document?

You can rotate images in the iText pdf document using the setRotation(final float r) or the setRotationDegrees(final float deg) methods of the com.itextpdf.text.Image class. This method sets the rotation in radian and in degree respectively. Let’s see an example below:

package org.kodejava.example.itextpdf;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.PdfWriter;

import java.io.FileOutputStream;
import java.io.IOException;

public class ImageRotateDemo {
    public static void main(String[] args) {
        Document doc = new Document();
        try {
            PdfWriter.getInstance(doc, new FileOutputStream("ImageRotation.pdf"));
            doc.open();

            // Rotate image in radian using the setRotation method.
            String filename = "other-sample/src/main/resources/java.gif";
            Image image = Image.getInstance(filename);
            image.setRotation(90f);
            doc.add(image);

            // The following line to prevent the "Server returned
            // HTTP response code: 403" error.
            System.setProperty("http.agent", "Chrome");

            // Rotate image in degree using the setRotationDegree method
            String url = "http://kodejava.org/wp-content/uploads/2017/01/kodejava.png";
            image = Image.getInstance(url);
            image.setRotationDegrees(90);
            doc.add(image);
        } catch (DocumentException | IOException e) {
            e.printStackTrace();
        } finally {
            doc.close();
        }
    }
}

Maven Dependencies

<!-- http://repo1.maven.org/maven2/com/itextpdf/itextpdf/5.5.10/itextpdf-5.5.10.jar -->
<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.10</version>
</dependency>

How do I rotate elements of a collection?

This example demonstrate how to rotate the elements of a collection object. We can use the java.util.Collections class and call the rotate() method with the collection to rotate and the distance as the parameters.

package org.kodejava.example.util;

import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Arrays;

public class CollectionRotate {
    public static void main(String[] args) {
        List numbers = new ArrayList();

        // Add some items into the collection
        for (int i = 0; i < 25; i++) {
            numbers.add(i);
        }

        // Print the collection items        
        System.out.println(Arrays.toString(numbers.toArray()));

        // Rotates the elements in the collection by the 10.
        Collections.rotate(numbers, 10);

        // Print the rotated collection items
        System.out.println(Arrays.toString(numbers.toArray()));
    }
}

Here is the program result:

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
[15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]