Apache PDFBox adding multiline paragraph

In the previous tutorial we saw how to create a PDF document with Apache PDFBox. In this tutorial we demonstrate how to add multiline paragraph to a PDF document using Apache PDFBox.

Maven Dependencies

We use Apache Maven to manage our project dependencies. Make sure the following dependencies reside on the class-path.

<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.8</version>
</dependency>

Apache PDFBox adding multiline paragraph

By default when you write a (long) text using PDPageContentStream#showText() it is printed on a single line. We need to calculate how many words will fit on a single line and then write the text to the document. We also wrote a feature to calculate the justified text which you can enable by passing a boolean argument. Take a look at the following example.

package com.memorynotfound.pdf.pdfbox;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.font.PDFont;
import org.apache.pdfbox.pdmodel.font.PDType1Font;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class MultiLineParagraph {

    private static final PDFont FONT = PDType1Font.HELVETICA;
    private static final float FONT_SIZE = 12;
    private static final float LEADING = -1.5f * FONT_SIZE;

    public static void main(String... args)  {

        try (final PDDocument doc = new PDDocument()){

            PDPage page = new PDPage();
            doc.addPage(page);
            PDPageContentStream contentStream = new PDPageContentStream(doc, page);

            PDRectangle mediaBox = page.getMediaBox();
            float marginY = 80;
            float marginX = 60;
            float width = mediaBox.getWidth() - 2 * marginX;
            float startX = mediaBox.getLowerLeftX() + marginX;
            float startY = mediaBox.getUpperRightY() - marginY;

            String text = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt" +
                    " ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco" +
                    " laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in " +
                    " ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco" +
                    " laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in " +
                    "voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat" +
                    " non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";

            contentStream.beginText();
            addParagraph(contentStream, width, startX, startY, text, true);
            addParagraph(contentStream, width, 0, -FONT_SIZE, text);
            addParagraph(contentStream, width, 0, -FONT_SIZE, text, false);
            contentStream.endText();

            contentStream.close();

            doc.save(new File("/tmp/example.pdf"));
        } catch (IOException e){
            System.err.println("Exception while trying to create pdf document - " + e);
        }
    }

    private static void addParagraph(PDPageContentStream contentStream, float width, float sx,
                                      float sy, String text) throws IOException {
        addParagraph(contentStream, width, sx, sy, text, false);
    }

    private static void addParagraph(PDPageContentStream contentStream, float width, float sx,
                                      float sy, String text, boolean justify) throws IOException {
        List<String> lines = parseLines(text, width);
        contentStream.setFont(FONT, FONT_SIZE);
        contentStream.newLineAtOffset(sx, sy);
        for (String line: lines) {
            float charSpacing = 0;
            if (justify){
                if (line.length() > 1) {
                    float size = FONT_SIZE * FONT.getStringWidth(line) / 1000;
                    float free = width - size;
                    if (free > 0 && !lines.get(lines.size() - 1).equals(line)) {
                        charSpacing = free / (line.length() - 1);
                    }
                }
            }
            contentStream.setCharacterSpacing(charSpacing);
            contentStream.showText(line);
            contentStream.newLineAtOffset(0, LEADING);
        }
    }

    private static List<String> parseLines(String text, float width) throws IOException {
        List<String> lines = new ArrayList<String>();
        int lastSpace = -1;
        while (text.length() > 0) {
            int spaceIndex = text.indexOf(' ', lastSpace + 1);
            if (spaceIndex < 0)
                spaceIndex = text.length();
            String subString = text.substring(0, spaceIndex);
            float size = FONT_SIZE * FONT.getStringWidth(subString) / 1000;
            if (size > width) {
                if (lastSpace < 0){
                    lastSpace = spaceIndex;
                }
                subString = text.substring(0, lastSpace);
                lines.add(subString);
                text = text.substring(lastSpace).trim();
                lastSpace = -1;
            } else if (spaceIndex == text.length()) {
                lines.add(text);
                text = "";
            } else {
                lastSpace = spaceIndex;
            }
        }
        return lines;
    }
}

Demo

The previous example generates the following PDF document.

References

• Apache PdfBox Official Website
• Apache PdfBox API Javadoc
• PDDocument JavaDoc
• PDPage JavaDoc
• PDPageContentStream JavaDoc

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