C# / .NET

dotnet add package RustPdf

using RustPdf;
Console.WriteLine(Pdf.Version());   // native library version

using RustPdf;

using var doc = new Document();          // A4 by default
doc.AddPage();
doc.SetFillRgb(0.86, 0.20, 0.18);
doc.Rect(72, 640, 200, 120);             // x, y, width, height (points)
doc.Fill();
doc.Save("out.pdf");

using var doc = new Document();
int font = doc.AddFontFile("Roboto-Regular.ttf");
doc.AddPage()
   .SetFillRgb(0.1, 0.1, 0.12)
   .Rect(0, 800, 595, 42).Fill()
   .ShowText(font, 24, 72, 740, "Olá, açúcar — café");
byte[] data = doc.ToBytes();             // a byte[] instead of a file

export RUSTPDF_LICENSE="010f0000…"           # the token we email you
# or point at a file:
export RUSTPDF_LICENSE_FILE=/etc/rustpdf/license.txt

using RustPdf;
Pdf.ActivateLicense(token);   // throws PdfException if forged / expired / malformed

// one document per task — no shared handle
var jobs = Enumerable.Range(0, 8).Select(i => Task.Run(() =>
{
    using var doc = new Document();
    doc.AddPage().SetFillRgb(0.1, 0.1, 0.12).Rect(72, 700, 200, 80).Fill();
    return doc.ToBytes();
}));
byte[][] pdfs = await Task.WhenAll(jobs);

using var doc = new Document();
doc.AddPage();
doc.SetStrokeRgb(0.10, 0.45, 0.90).SetLineWidth(3);
doc.Rect(72, 600, 300, 160).Stroke();
doc.SetFillRgb(0.95, 0.77, 0.06);
doc.Rect(120, 640, 120, 80).Fill();
doc.Save("shapes.pdf");

using var doc = new Document();
int regular = doc.AddFontFile("Roboto-Regular.ttf");
// …or from bytes you already have in memory:
// int regular = doc.AddFont(File.ReadAllBytes("Roboto-Regular.ttf"));

doc.AddPage();
doc.ShowText(regular, 28, 72, 760, "Invoice #1024");
doc.ShowText(regular, 12, 72, 720, "日本語 · Ελληνικά · العربية");
doc.Save("text.pdf");

using RustPdf;

string intro =
    "A long paragraph that wraps to the given width and is justified " +
    "automatically; extra space is distributed between words.";

using var doc = new Document();
int f = doc.AddFontFile("Roboto-Regular.ttf");
doc.AddPage();
doc.Paragraph(f, 12, 72, 700, 451, intro, Align.Justify);
doc.Save("paragraph.pdf");

using var doc = new Document();
int logo = doc.AddImageFile("logo.png");
doc.AddPage();
doc.DrawImage(logo, 72, 680, 160, 90);
doc.Save("with_image.pdf");

using RustPdf;

using var doc = new Document();
doc.Pdfa(PdfaLevel.A2b).SetInfo(title: "Q3 Report", author: "Acme Inc.");
int f = doc.AddFontFile("Roboto-Regular.ttf");
doc.AddPage();
doc.ShowText(f, 20, 72, 760, "Archival report");
doc.Save("report_pdfa.pdf");     // throws PdfException without a license granting PDF/A

using RustPdf;

using var doc = new Document();
doc.Pdfa(PdfaLevel.A2a).Tagged().SetInfo(title: "Accessible report");
int f = doc.AddFontFile("Roboto-Regular.ttf");
doc.AddPage();
doc.ShowText(f, 26, 72, 760, "Annual report", headingLevel: 1);   // H1
doc.ShowText(f, 14, 72, 720, "Overview", headingLevel: 2);         // H2
doc.ShowText(f, 11, 72, 690, "Body paragraph of the section…");
int chart = doc.AddImageFile("chart.png");
doc.Figure(chart, 72, 520, 300, 150, "Revenue grew 18% year over year");
doc.Save("accessible.pdf");

using RustPdf;

byte[] xml = File.ReadAllBytes("invoice.xml");
using var doc = new Document();
doc.Pdfa(PdfaLevel.A3b).SetInfo(title: "E-invoice 1024");
int f = doc.AddFontFile("Roboto-Regular.ttf");
doc.AddPage();
doc.ShowText(f, 18, 72, 760, "Invoice 1024");
doc.AttachFile("invoice.xml", "text/xml", xml,
               AFRelationship.Source, "Structured invoice data");
doc.Save("einvoice.pdf");

using RustPdf;

byte[] xml = File.ReadAllBytes("factur-x.xml");   // your Cross-Industry Invoice XML
using var doc = new Document();
doc.SetInfo(title: "Invoice INV-2026-001");
int f = doc.AddFontFile("Roboto-Regular.ttf");
doc.AddPage();
doc.ShowText(f, 18, 72, 760, "Invoice INV-2026-001");
doc.Facturx(xml, FacturxProfile.En16931);
doc.Save("einvoice.pdf");        // PDF/A-3 + Factur-X; needs a PDF/A license

using var doc = new Document();
doc.AddPage();
doc.TextField("applicant.name", 0, (72, 700, 320, 720));
doc.Checkbox("agree", 0, (72, 660, 88, 676), false);
doc.Dropdown("plan", 0, (72, 620, 240, 640),
             new[] { "Starter", "Pro", "Enterprise" }, selected: 1);
doc.RadioGroup("billing", 0, new[]
{
    ((72.0, 580.0, 88.0, 596.0), "monthly"),
    ((140.0, 580.0, 156.0, 596.0), "annual"),
}, selected: 1);
doc.Save("form.pdf");

using var doc = new Document();
int f = doc.AddFontFile("Roboto-Regular.ttf");
doc.AddPage();
doc.ShowText(f, 14, 72, 760, "Visit rustpdf.dev (see page 2)");
doc.LinkUri((72, 756, 320, 776), "https://rustpdf.dev/");   // web link
doc.LinkToPage((330, 756, 430, 776), 1, top: 800);         // jump to page 2
doc.AddPage();
doc.Save("links.pdf");

using RustPdf;

using var doc = new Document();
int f = doc.AddFontFile("Roboto-Regular.ttf");
for (int i = 0; i < 3; i++)
    doc.AddPage();
doc.AddBookmark(
    new Bookmark("Chapter 1", 0, top: 820)
        .Child(new Bookmark("Section 1.1", 1))
        .Child(new Bookmark("Section 1.2", 2)));
doc.AddBookmark(new Bookmark("Chapter 2", 2));
doc.Save("outline.pdf");

doc.SetInfo(title: "Q3 Report", author: "Acme Inc.",
            subject: "Quarterly results", keywords: "finance, q3");

using RustPdf;

using (var ed = EditableDoc.LoadFile("in.pdf"))
    Console.WriteLine(ed.PageCount);

// encrypted input:
using var sec = EditableDoc.LoadFile("secured.pdf", "user-or-owner-pw");
sec.Save("plain.pdf");

using var a = EditableDoc.LoadFile("a.pdf");
using (var b = EditableDoc.LoadFile("b.pdf"))
    a.Merge(b);                        // a now has a's pages followed by b's
a.RotatePage(0, 90);
a.ReorderPages(Enumerable.Range(0, a.PageCount).Reverse().ToList());
a.Save("merged.pdf");

using var subset = a.ExtractPages(new[] { 0, 2 });   // pages 1 and 3
subset.Save("subset.pdf");

using var ed = EditableDoc.LoadFile("form.pdf");
ed.SetInfo("Title", "Filled form");
bool found = ed.FillTextField("applicant.name", "Jane Doe");
Console.WriteLine($"filled: {found} | title: {ed.GetInfo("Title")}");
ed.Save("filled.pdf");

using RustPdf;

using var ed = EditableDoc.LoadFile("form.pdf");
Console.WriteLine(string.Join(", ", ed.FieldNames()));   // applicant.name, agree, plan, ...
ed.FillTextField("applicant.name", "Jane Doe");
ed.SetCheckbox("agree", true);
ed.SetRadio("billing", "annual");
ed.SetChoice("plan", "Pro");
ed.FlattenForms();                  // optional: make it non-editable
ed.Save("filled.pdf");

using var ed = EditableDoc.LoadFile("report.pdf");
ed.WatermarkText("CONFIDENTIAL", color: (0.7, 0.1, 0.1),
                 opacity: 0.25, rotationDeg: 45);
ed.Save("stamped.pdf");

using var ed = EditableDoc.LoadFile("statement.pdf");
// rects = list of (x0, y0, x1, y1) tuples on that page
ed.Redact(0, new[]
{
    (60.0, 590.0, 400.0, 620.0),
    (60.0, 540.0, 400.0, 570.0),
});
ed.Save("redacted.pdf");     // throws PdfException without a license granting redaction

using RustPdf;

using var ed = EditableDoc.LoadFile("in.pdf");
ed.ConvertToPdfa(PdfaLevel.A2b);    // throws PdfException if fonts aren't embedded
ed.Save("archival.pdf");            // veraPDF: PDF/A-2b compliant

using var ed = EditableDoc.LoadFile("big.pdf");
ed.Optimize().Compact(true);
ed.Save("small.pdf");

using RustPdf;

using var ed = EditableDoc.LoadFile("in.pdf");
ed.Encrypt(user: "", owner: "owner-secret",
           method: Encryption.Aes256, readOnly: true);
ed.Save("secured.pdf");          // throws PdfException without an Encryption license

byte[] original = File.ReadAllBytes("in.pdf");
using var ed = EditableDoc.Load(original);
ed.SetInfo("Subject", "reviewed");
byte[] incremental = ed.ToBytesIncremental(original);   // original bytes preserved verbatim
File.WriteAllBytes("reviewed.pdf", incremental);

using RustPdf;

byte[] pdf     = File.ReadAllBytes("contract.pdf");
byte[] keyDer  = File.ReadAllBytes("signing-key.pkcs8.der");   // PKCS#8 private key (DER)
byte[] certDer = File.ReadAllBytes("signing-cert.der");        // X.509 certificate (DER)

byte[] signed = Pdf.Sign(pdf, keyDer, certDer,
    reason: "Approved", location: "New York",
    name: "Jane Doe", pades: true);
File.WriteAllBytes("contract.signed.pdf", signed);
// Verify in a shell: pdfsig contract.signed.pdf  →  "Signature is Valid."

byte[] signed = File.ReadAllBytes("contract.signed.pdf");

// B-LT: embed validation material (caller supplies DER certs/CRLs)
byte[] lt = Pdf.AddDss(signed, new[] { certDer }, new[] { crlDer });

// B-LTA: add a document timestamp signed by a TSA key/cert
byte[] lta = Pdf.Timestamp(lt, tsaKeyDer, tsaCertDer);
File.WriteAllBytes("contract.lta.pdf", lta);

using RustPdf;

byte[] data = File.ReadAllBytes("contract.signed.pdf");
foreach (SignatureInfo sig in Pdf.VerifySignatures(data))
    Console.WriteLine($"{sig.Signer} valid: {sig.IsValid} " +
                      $"covers whole doc: {sig.CoversWholeDocument}");

byte[] data = File.ReadAllBytes("report.pdf");
Console.WriteLine(Pdf.ExtractText(data));

int n = Pdf.ExtractImagesToDir(data, "out_images/");   // returns how many were written
Console.WriteLine($"wrote {n} image(s)");

byte[] data = File.ReadAllBytes("report.pdf");
Console.WriteLine($"{Pdf.PageCount(data)} page(s)");
byte[] png = Pdf.RenderPageToPng(data, pageIndex: 0, dpi: 150.0);
File.WriteAllBytes("page1.png", png);

using RustPdf;

try
{
    using var doc = new Document();
    doc.Pdfa().SetInfo(title: "x");
    doc.AddPage();
    doc.Save("out.pdf");
}
catch (PdfException e)
{
    Console.Error.WriteLine($"failed: {e.Status} {e.Message}");
    // e.g. PdfStatus=4 (Serialize): feature 'pdfa' requires a valid license
}