How to Fix CSS border-radius in iTextSharp HTML-to-PDF Conversion

If rounded corners disappear from an iTextSharp PDF, the first fix is usually choosing the correct parser and proving that valid XHTML and CSS actually reach it. HTMLWorker is the wrong place to debug modern CSS; iText documents it as limited, without CSS-file support in the cited scenario, and no longer developed. For legacy iText 5 applications, investigate XML Worker, then test a minimal example with the exact package version and element you use. Do not assume that a browser or current pdfHTML result proves that XML Worker supports border-radius.

Start by identifying the conversion engine

Search the conversion code before changing the stylesheet. The class and method names tell you which CSS implementation is evaluating your markup.

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See iText’s explanation of the parser distinction in “Why doesn’t CSS and RowSpan work?” and its conversion walkthrough in “How to convert HTML to PDF?”.

Use valid XHTML and a deliberately small test case

XML Worker is not a browser. A page that looks correct in Chrome can still contain markup that the XML parser cannot consume. Start with one block, an explicit size, a border, a background, and a radius:

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<!DOCTYPE html>
<html xmlns='http://www.w3.org/1999/xhtml'>
  <head>
    <meta http-equiv='Content-Type' content='text/html; charset=UTF-8' />
    <style type='text/css'>
      .card {
        width: 240px;
        height: 120px;
        border: 2px solid #2563eb;
        border-radius: 16px;
        background-color: #dbeafe;
      }
    </style>
  </head>
  <body>
    <div class='card'>Rounded test block</div>
  </body>
</html>

• Close every element, including empty elements such as <meta />.
• Use quoted attribute values and properly nested tags.
• Begin with a block element rather than a table cell, nested layout, or a pseudo-element.
• Specify the border, dimensions, and background so you can distinguish a missing radius from a missing box.

Once this minimal document behaves as expected, add your real markup one component at a time. If the minimal case fails, changing unrelated application CSS will not identify the cause.

Make sure CSS reaches XML Worker

The official guide demonstrates two relevant forms of ParseXHtml: one that receives HTML and another that receives separate HTML and CSS streams. Choose one delivery method and verify it rather than assuming a browser-style relative URL will resolve.

Inline CSS

Inline or embedded styles keep the reproduction self-contained. This C# shape follows the documented XML Worker lifecycle; adapt namespaces and project references to your application:

using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.tool.xml;

var html = @"<html xmlns='http://www.w3.org/1999/xhtml'>
  <head>
    <style type='text/css'>
      .card { width:240px; height:120px; border:2px solid #2563eb;
              border-radius:16px; background-color:#dbeafe; }
    </style>
  </head>
  <body><div class='card'>Rounded test block</div></body>
</html>";

using (var output = File.Create("rounded.pdf"))
using (var document = new Document())
{
    var writer = PdfWriter.GetInstance(document, output);
    document.Open();
    using (var srHtml = new StringReader(html))
    {
        XMLWorkerHelper.GetInstance().ParseXHtml(writer, document, srHtml);
    }
    document.Close();
}

Keep the document open while parsing and keep the reader and output stream alive for the whole conversion. The example is a conversion pattern, not proof that every XML Worker release renders border-radius.

Separate HTML and CSS streams

When CSS is stored separately, convert both strings to UTF-8 bytes and pass both streams to the overload shown in iText’s guide:

using System.IO;
using System.Text;
using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.tool.xml;

byte[] htmlBytes = Encoding.UTF8.GetBytes(html);
byte[] cssBytes  = Encoding.UTF8.GetBytes(css);

using (var htmlStream = new MemoryStream(htmlBytes))
using (var cssStream = new MemoryStream(cssBytes))
using (var output = File.Create("rounded.pdf"))
using (var document = new Document())
{
    var writer = PdfWriter.GetInstance(document, output);
    document.Open();
    XMLWorkerHelper.GetInstance().ParseXHtml(writer, document,
                                              htmlStream, cssStream);
    document.Close();
}

This avoids a missing or inaccessible stylesheet URL. If you use an absolute link instead, verify that the conversion process can read it in its deployment environment; do not assume the server’s current directory or a browser cache is available.

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Test the exact property and element you need

The official sources do not provide a version-by-version compatibility table for border-radius in XML Worker. Consequently, there is no responsible universal answer such as “all divs work” or “all table cells fail.” Run the smallest test with the exact iTextSharp/XML Worker package versions, target framework, and element used by your application.

1. Render a plain div with a solid border and radius.
2. Render the same rule on the real element, such as a table cell or nested container.
3. Replace the radius temporarily with a conspicuous background and border to establish that the selector matches.
4. Try each corner property separately only after the shorthand case is understood.
5. Compare the generated PDF, not an HTML preview, and preserve the input and package versions with the test result.

If the plain block works but the production element does not, the issue is element support or layout interaction, not simply a missing semicolon. Use a different markup structure only after the minimal reproduction demonstrates that it changes the result.

Why browser CSS and pdfHTML documentation can mislead you

Two different comparisons are commonly confused:

• Browser versus XML Worker: browser engines implement a much broader CSS and layout model. Browser success is not evidence that XML Worker will paint the same corner.
• pdfHTML versus XML Worker: they belong to different iText generations. The current pdfHTML feature matrix lists border-radius, plus the four corner-specific radius properties, for pdfHTML 6.3.3 released with iText Core 9.7.0. That listing is scoped to pdfHTML and is not a guarantee for legacy iTextSharp XML Worker.

Check the current matrix at iText’s pdfHTML feature support page, but apply its entries only to the stated pdfHTML release and not to an iText 5 parser.

When migration is the practical fix

The iTextSharp project repository marks iTextSharp as end of life and says: “PLEASE NOTE: iTextSharp is EOL, and has been replaced by iText 7. Only security fixes will be added”. If a required corner style is blocked by the legacy parser, migration may be more predictable than accumulating CSS workarounds.

Do not migrate solely because a browser screenshot has rounded corners. Migrate when your tested requirements, maintenance policy, and deployment constraints justify the newer conversion stack.

Troubleshooting checklist

Operational practices for reliable PDF output

• Keep a minimal XHTML fixture in automated tests so a library update cannot silently square every corner.
• Test representative elements separately: block, nested block, table, and table cell.
• Archive the input HTML, CSS, package versions, and generated PDF for a failing case.
• Use deterministic local resources during testing; network-dependent stylesheets make parser failures harder to distinguish from connectivity failures.
• Check licensing and deployment requirements independently before shipping either the legacy or newer iText generation.

Or skip the browser setup

If your actual requirement is a clean image or PDF capture of a web page, rather than server-side conversion of HTML under your control, ScreenshotNeo provides a one-request alternative. It accepts consent banners before capture and removes more than 60 known consent platforms, newsletter popups, and chat widgets; bot checks, blank pages, timeouts, failed loads, and cache hits are not billed, and response headers identify the page verdict and billing result. Its MCP server exposes take_screenshot, get_page_info, and capture_pdf to Claude, Cursor, and other MCP clients.

For API parameters and the complete option list, see the ScreenshotNeo documentation. A direct request looks like this:

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curl -G "https://api.screenshotneo.com/v1/shot" -d access_key=YOUR_API_KEY --data-urlencode url=https://stripe.com -o shot.webp

The same call in Python:

import requests
r = requests.get("https://api.screenshotneo.com/v1/shot", params={"access_key": "YOUR_API_KEY", "url": "https://stripe.com"}, timeout=90)
open("shot.webp", "wb").write(r.content)

And in Node.js:

const q = new URLSearchParams({ access_key: 'YOUR_API_KEY', url: 'https://stripe.com' });
const res = await fetch(`https://api.screenshotneo.com/v1/shot?${q}`);

ScreenshotNeo includes full-page and element capture, device presets, custom CSS and JavaScript, waits, request blocking, cookies and headers, PDF controls, caching, signed links, asynchronous webhooks, bulk capture, and a usage API on every plan. The Free plan includes 1,000 screenshots per month with no card; paid plans start at $5 for 3,000 screenshots. Create a free ScreenshotNeo account to try it.

FAQ

Is a square corner always evidence that the CSS selector failed?

No. A visible border with square corners proves that some box styling reached the output, but it does not establish that the parser supports the radius on that element. Use the minimal control and exact-element test.

Can I claim XML Worker supports every CSS property listed for pdfHTML?

No. The two conversion generations have separate implementations and documentation. Treat pdfHTML feature entries as scoped to the stated pdfHTML release.

What should I preserve when reporting a rendering bug?

Provide the smallest valid XHTML, the CSS, the target element, the generated PDF, and the exact iTextSharp/XML Worker package and runtime versions. That information makes the behavior reproducible instead of anecdotal.

Frequently Asked Questions

Is a square corner always evidence that the CSS selector failed?

No. A visible border with square corners proves that some box styling reached the output, but it does not establish that the parser supports the radius on that element. Use the minimal control and exact-element test.

Can I claim XML Worker supports every CSS property listed for pdfHTML?

No. The two conversion generations have separate implementations and documentation. Treat pdfHTML feature entries as scoped to the stated pdfHTML release.

What should I preserve when reporting a rendering bug?

Provide the smallest valid XHTML, the CSS, the target element, the generated PDF, and the exact iTextSharp/XML Worker package and runtime versions. That information makes the behavior reproducible instead of anecdotal.

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