How can I create fixed-width paragraphs with PDFbox?

Question

I can insert simple text like this:

document = new PDDocument();
page = new PDPage(PDPage.PAGE_SIZE_A4);
document.addPage(page);
PDPageContentStream content = new PDPageContentStream(document, page);
content.beginText();
content.moveTextPositionByAmount (10 , 10);
content.drawString ("test text");
content.endText();
content.close();

but how can I create a paragraph similar to HTML using the width attribute?

<p style="width:200px;">test text</p>

Answer 1

Warning: this answer applies to and old version of PDFBox and relies on features that has since been deprecated. See the comments below for more details.

According to this answer it's not possible to insert line breaks into some text and have PDF display it correctly (whether using PDFBox or something else), so I believe auto-wrapping some text to fit in some width may also be something it can't do automatically. (besides, there are many ways to wrap a text - whole words only, break them in smaller parts, etc)

This answer to another question (about centering a string) gives some pointers on how to do this yourself. Assuming you wrote a function possibleWrapPoints(String):int[] to list all points in the text a word wrap can happen (excluding "zero", including "text length"), one possible solution could be:

PDFont font = PDType1Font.HELVETICA_BOLD; // Or whatever font you want.
int fontSize = 16; // Or whatever font size you want.
int paragraphWidth = 200;
String text = "test text";

int start = 0;
int end = 0;
int height = 10;
for ( int i : possibleWrapPoints(text) ) {
    float width = font.getStringWidth(text.substring(start,i)) / 1000 * fontSize;
    if ( start < end && width > paragraphWidth ) {
        // Draw partial text and increase height
        content.moveTextPositionByAmount(10 , height);
        content.drawString(text.substring(start,end));
        height += font.getFontDescriptor().getFontBoundingBox().getHeight() / 1000 * fontSize;
        start = end;
    }
    end = i;
}
// Last piece of text
content.moveTextPositionByAmount(10 , height);
content.drawString(text.substring(start));

One example of possibleWrapPoints, that allow wrapping at any point that's not part of a word (reference), could be:

int[] possibleWrapPoints(String text) {
    String[] split = text.split("(?<=\\W)");
    int[] ret = new int[split.length];
    ret[0] = split[0].length();
    for ( int i = 1 ; i < split.length ; i++ )
        ret[i] = ret[i-1] + split[i].length();
    return ret;
}

Update: some additional info:

• The PDF file format was designed to look the same in different situations, functionality like the one you requested makes sense in a PDF editor/creator, but not in the PDF file per se. For this reason, most "low level" tools tend to concentrate on dealing with the file format itself and leave away stuff like that.

• Higher level tools OTOH usually have means to make this conversion. An example is Platypus (for Python, though), that do have easy ways of creating paragraphs, and relies on the lower level ReportLab functions to do the actual PDF rendering. I'm unaware of similar tools for PDFBox, but this post gives some hints on how to convert HTML content to PDF in a Java environment, using freely available tools. Haven't tried them myself, but I'm posting here since it might be useful (in case my hand-made attempt above is not enough).

Answer 2

I have been working combining Lukas answer with mgibsonbr and arrived at this. More helpful to people looking for an out-of-the-box solution, I think.

private void write(Paragraph paragraph) throws IOException {
    out.beginText();
    out.appendRawCommands(paragraph.getFontHeight() + " TL\n");
    out.setFont(paragraph.getFont(), paragraph.getFontSize());
    out.moveTextPositionByAmount(paragraph.getX(), paragraph.getY());
    out.setStrokingColor(paragraph.getColor());

    List<String> lines = paragraph.getLines();
    for (Iterator<String> i = lines.iterator(); i.hasNext(); ) {
        out.drawString(i.next().trim());
        if (i.hasNext()) {
            out.appendRawCommands("T*\n");
        }
    }
    out.endText();

}

public class Paragraph {

    /** position X */
    private float x;

    /** position Y */
    private float y;

    /** width of this paragraph */
    private int width = 500;

    /** text to write */
    private String text;

    /** font to use */
    private PDType1Font font = PDType1Font.HELVETICA;

    /** font size to use */
    private int fontSize = 10;

    private int color = 0;

    public Paragraph(float x, float y, String text) {
        this.x = x;
        this.y = y;
        this.text = text;
    }

    /**
     * Break the text in lines
     * @return
     */
    public List<String> getLines() throws IOException {
        List<String> result = Lists.newArrayList();

        String[] split = text.split("(?<=\\W)");
        int[] possibleWrapPoints = new int[split.length];
        possibleWrapPoints[0] = split[0].length();
        for ( int i = 1 ; i < split.length ; i++ ) {
            possibleWrapPoints[i] = possibleWrapPoints[i-1] + split[i].length();
        }

        int start = 0;
        int end = 0;
        for ( int i : possibleWrapPoints ) {
            float width = font.getStringWidth(text.substring(start,i)) / 1000 * fontSize;
            if ( start < end && width > this.width ) {
                result.add(text.substring(start,end));
                start = end;
            }
            end = i;
        }
        // Last piece of text
        result.add(text.substring(start));
        return result;
    }

    public float getFontHeight() {
        return font.getFontDescriptor().getFontBoundingBox().getHeight() / 1000 * fontSize;
    }

    public Paragraph withWidth(int width) {
        this.width = width;
        return this;
    }

    public Paragraph withFont(PDType1Font font, int fontSize) {
        this.font = font;
        this.fontSize = fontSize;
        return this;
    }

    public Paragraph withColor(int color) {
        this.color = color;
        return this;
    }

    public int getColor() {
        return color;
    }

    public float getX() {
        return x;
    }

    public float getY() {
        return y;
    }

    public int getWidth() {
        return width;
    }

    public String getText() {
        return text;
    }

    public PDType1Font getFont() {
        return font;
    }

    public int getFontSize() {
        return fontSize;
    }

}