ImageConvertOptions options = new ImageConvertOptions();
options.setFormat(ImageSaveOptions.ImageFormat.PNG);
options.setQuality(90);
options.setPageNumber(pageIndex);

ExecutorService executor = Executors.newFixedThreadPool(
        Runtime.getRuntime().availableProcessors());
executor.submit(() -> {
    // conversion logic per page
});

import com.groupdocs.conversion.Converter;
import com.groupdocs.conversion.options.convert.ImageConvertOptions;
import com.groupdocs.conversion.options.convert.ImageSaveOptions;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class ConvertOneNoteToImage {
    public static void main(String[] args) {
        String inputPath = "sample.one";
        String outputPattern = "output_page_%d.png";
        int imageQuality = 90; // 0-100

// Thread pool for parallel page conversion
        ExecutorService executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

try (InputStream fileStream = new BufferedInputStream(new FileInputStream(inputPath));
             Converter converter = new Converter(fileStream)) {

int pageCount = converter.getPageCount();

for (int i = 0; i < pageCount; i++) {
                final int pageIndex = i;
                executor.submit(() -> {
                    ImageConvertOptions options = new ImageConvertOptions();
                    options.setFormat(ImageSaveOptions.ImageFormat.PNG);
                    options.setQuality(imageQuality);
                    options.setPageNumber(pageIndex); // zero‑based page index

String outputPath = String.format(outputPattern, pageIndex + 1);
                    try (OutputStream outStream = new BufferedOutputStream(new FileOutputStream(outputPath))) {
                        converter.convert(outStream, options);
                        System.out.println("Page " + (pageIndex + 1) + " saved to " + outputPath);
                    } catch (Exception e) {
                        System.err.println("Failed to convert page " + (pageIndex + 1) + ": " + e.getMessage());
                    }
                });
            }

// Example of in‑memory conversion for the first page
            ImageConvertOptions memOptions = new ImageConvertOptions();
            memOptions.setFormat(ImageSaveOptions.ImageFormat.JPEG);
            memOptions.setQuality(imageQuality);
            memOptions.setPageNumber(0);
            try (ByteArrayOutputStream memoryStream = new ByteArrayOutputStream()) {
                converter.convert(memoryStream, memOptions);
                byte[] imageBytes = memoryStream.toByteArray();
                System.out.println("In‑memory conversion produced " + imageBytes.length + " bytes for page 1.");
                // imageBytes can now be sent over network, stored in DB, etc.
            } catch (Exception e) {
                System.err.println("In‑memory conversion error: " + e.getMessage());
            }

} catch (IOException e) {
            System.err.println("File access error: " + e.getMessage());
        } catch (Exception e) {
            System.err.println("Conversion initialization error: " + e.getMessage());
        } finally {
            executor.shutdown();
            try {
                if (!executor.awaitTermination(60, TimeUnit.SECONDS)) {
                    executor.shutdownNow();
                }
            } catch (InterruptedException ie) {
                executor.shutdownNow();
                Thread.currentThread().interrupt();
            }
        }
    }
}

<repositories>
    <repository>
        <id>conholdate-repo</id>
        <name>Conholdate Maven Repository</name>
        <url>https://repository.conholdate.com/repo/</url>
    </repository>
</repositories>

<dependency>
    <groupId>com.conholdate</groupId>
    <artifactId>conholdate-total</artifactId>
    <version>24.9</version>
    <type>pom</type>
</dependency>