Generate a Report

Build a multi-page report with a cover page, section headings, body text, and page numbers.

Structure

Page 1: Cover
Page 2+: Sections
  - Section heading
  - Body paragraphs
  - Optional table or image
Last page: page numbers in footer

Font setup

Register both font weights once on the document. The same PdfFont handle is reused across all pages.

PdfFont boldFont    = doc.registerFont(
    getClass().getResourceAsStream("/fonts/Inter-Bold.ttf").readAllBytes());
PdfFont regularFont = doc.registerFont(
    getClass().getResourceAsStream("/fonts/Inter-Regular.ttf").readAllBytes());

Cover page

try (PdfDocument doc = new PdfDocument();
     FileOutputStream out = new FileOutputStream("report.pdf")) {

    doc.setTitle(report.title());
    doc.setAuthor(report.author());
    doc.setCreator("Reporting Engine v2");

    PdfFont boldFont    = doc.registerFont(
        getClass().getResourceAsStream("/fonts/Inter-Bold.ttf").readAllBytes());
    PdfFont regularFont = doc.registerFont(
        getClass().getResourceAsStream("/fonts/Inter-Regular.ttf").readAllBytes());

    // ── Cover ─────────────────────────────────────────────────────
    PdfPage cover = doc.addPage(595, 842);

    cover.fillRect(0, 0, 595, 842);   // dark background — see Colors and Styling

    cover.drawTextBox(72, 500, 450, 60,  report.title(),    boldFont,    28);
    cover.drawTextBox(72, 440, 300, 30,  report.subtitle(), regularFont, 14);
    cover.drawTextBox(72, 100, 300, 20,  report.date(),     regularFont, 11);

    // ── Content pages ──────────────────────────────────────────────
    for (Section section : report.sections()) {
        PdfPage page = doc.addPage(595, 842);
        int y = 770;

        page.drawTextBox(72, y, 450, 28, section.title(), boldFont, 16);
        y -= 36;

        page.drawLine(72, y, 523, y);
        y -= 20;

        for (String paragraph : section.paragraphs()) {
            int blockHeight = estimateHeight(paragraph, 450, 11);
            page.drawTextBox(72, y, 450, blockHeight, paragraph, regularFont, 11);
            y -= blockHeight + 12;
        }

        // Page number footer
        int pageNum = report.sections().indexOf(section) + 2;
        page.drawTextBox(72, 40, 450, 14,
            "Page " + pageNum + " of " + (report.sections().size() + 1),
            regularFont, 9);
    }

    doc.writeTo(out);
}

Text height estimation

PDFixa draws text inside a fixed rectangle (drawTextBox). It does not return how much vertical space the text consumed, so you need to estimate height before drawing to make pagination decisions.

How text height works in PDF

A text block's height depends on three values:

Term	Meaning	Typical value
Font size	The em-square size in PDF points (1/72 inch)	10–12 pt for body
Line height	Vertical distance between baselines of consecutive lines	fontSize × 1.2 to fontSize × 1.5
Line count	Number of wrapped lines = ⌈textLength / charsPerLine⌉	Depends on box width

The total block height is lineCount × lineHeight.

The tricky part is characters per line: it depends on the average glyph width of the font. For proportional fonts (like Inter or Helvetica), characters vary in width — "W" is roughly 3× wider than "i". A good rule of thumb for Latin text:

• Sans-serif (Helvetica, Inter): average character width ≈ fontSize × 0.5
• Serif (Times): average character width ≈ fontSize × 0.45
• Monospace (Courier): average character width ≈ fontSize × 0.6

Helper implementation

static int estimateHeight(String text, int boxWidth, double fontSize) {
    return estimateHeight(text, boxWidth, fontSize, 1.35, 0.5);
}

static int estimateHeight(String text, int boxWidth, double fontSize,
                          double lineSpacingFactor, double charWidthFactor) {
    if (text == null || text.isEmpty()) {
        return (int) Math.ceil(fontSize * lineSpacingFactor);
    }

    double avgCharWidth = fontSize * charWidthFactor;
    int charsPerLine    = Math.max(1, (int) (boxWidth / avgCharWidth));
    int lineCount       = (text.length() + charsPerLine - 1) / charsPerLine;
    double lineHeight   = fontSize * lineSpacingFactor;

    return (int) Math.ceil(lineCount * lineHeight);
}

The two-argument version uses sensible defaults (1.35 line spacing, 0.5 char width factor). Override when you need tighter or looser layout:

// Tight layout for table cells
int h = estimateHeight(cellText, 200, 9, 1.15, 0.48);

// Loose layout for reading paragraphs
int h = estimateHeight(paragraph, 450, 11, 1.5, 0.52);

Calibration

The estimate is approximate. If text overflows or leaves too much whitespace:

1. Increase charWidthFactor (e.g. 0.55) if text wraps earlier than expected.
2. Decrease it (e.g. 0.45) if lines are shorter than the box.
3. Adjust lineSpacingFactor to tighten (1.2) or loosen (1.5) vertical rhythm.

For pixel-accurate layout, read glyph metrics from the .ttf file directly (e.g. with java.awt.Font or a font parsing library) and sum actual glyph advance widths.

Pagination helper

When content may overflow a page, track available space and start a new page when needed:

PdfFont regularFont = doc.registerFont(
    getClass().getResourceAsStream("/fonts/Inter-Regular.ttf").readAllBytes());

int y         = 770;
int minY      = 60;   // reserve space for footer
PdfPage page  = doc.addPage(595, 842);

for (String paragraph : paragraphs) {
    int blockHeight = estimateHeight(paragraph, 450, 11);

    if (y - blockHeight < minY) {
        page = doc.addPage(595, 842);
        y    = 770;
    }

    page.drawTextBox(72, y, 450, blockHeight, paragraph, regularFont, 11);
    y -= blockHeight + 12;
}

Key patterns

• Cover page first — addPage before content pages so they are page 1 in the PDF.
• Page numbers — derived from section index, never from runtime state.
• Determinism — report.date() comes from your data, not LocalDate.now().

See Documents for writing to streams, and Fonts for registering boldFont and regularFont.