BarcodeSvg.Net 0.1.0

BarcodeSvg.NET

Code 128 and EAN-13 barcodes rendered as self-contained SVG for .NET. No System.Drawing, no native imaging library, no runtime dependencies at all.

Most .NET barcode libraries either wrap System.Drawing.Common (Windows-only in practice, and Microsoft has been steering people away from it for years) or pull in a native imaging dependency to rasterize bitmaps. Neither belongs in a server-side PDF pipeline, an Azure Function, or anything you want to run on Linux or in a container. An SVG is just text: it drops straight into a browser, a PDF generator, or an email template, scales without artifacts, and needs nothing installed on the machine that renders it. BarcodeSvg.NET produces that text directly, with the two symbologies that cover the overwhelming majority of real-world barcoding: Code 128 for arbitrary alphanumeric data (invoice numbers, tracking codes, IDs) and EAN-13 for retail product barcodes.

Where the numbers matter, the library gets them right and proves it: the Code 128 check character (weighted modulo 103) and its automatic Code Set A/B/C switching, and the EAN-13 check digit (weighted modulo 10) and its left-hand odd/even parity pattern, are all verified against independently computed reference patterns, not just "it ran without throwing."

Install

dotnet add package BarcodeSvg.Net

Quickstart

using BarcodeSvg;

string svg = Code128Barcode.ToSvg("INV-2026-004821");

That single call encodes the text and renders it straight to an SVG string, ready to embed in HTML, hand to a PDF library, or write to a file.

EAN-13 with a computed check digit

using BarcodeSvg;

// 12 digits in: the check digit is computed and appended automatically.
string svg = Ean13Barcode.ToSvg("400638133393");

Pass all 13 digits instead and the library validates the check digit for you, throwing a FormatException if it does not match, which catches typos before a mis-printed barcode ships.

Sizing, color and the human-readable text line

using BarcodeSvg;

var options = new BarcodeRenderOptions
{
    ModuleWidth = 2.5,
    Height = 60,
    QuietZoneWidth = 20,
    BarColor = "#111111",
    Text = "Invoice INV-2026-004821",
};

string svg = Code128Barcode.ToSvg("INV-2026-004821", options);

Set ShowText = false to omit the human-readable line entirely. Whatever text you supply (or the raw encoded value, if you do not override it) is XML-escaped before it reaches the SVG, so it cannot break the markup or inject content, even if it originated from user input.

Working with the raw pattern

If you want to rasterize a barcode yourself, drive a thermal printer, or just inspect what was encoded, skip the SVG renderer and use the encoder directly:

using BarcodeSvg;

BarcodePattern pattern = Code128Encoder.Encode("INV-2026-004821");

foreach (BarSegment segment in pattern.Bars)
{
    // segment.IsBar: true for a dark bar, false for a light space
    // segment.WidthInModules: how many module-widths wide this run is
}

BarcodePattern also exposes TotalModules, the symbology's RecommendedQuietZoneModules, and the default HumanReadableText, everything BarcodeSvgRenderer.Render(pattern, options) needs, and everything a custom renderer needs too.

What is verified, and how

• Code 128 checksum: the weighted modulo-103 check character formula (start value + Σ symbol value × position, mod 103), verified against an independently written Python reference encoder and hand-checked arithmetic.
• Code 128 code-set switching: automatic Code Set A/B/C selection with LATCH for runs of two or more characters that need the other set, SHIFT for a single isolated character, and the exact digit-run threshold (four or more consecutive digits) that triggers Code Set C, including the odd-leftover-digit case where a run packs as many pairs as it can and falls back to A/B for the last digit.
• EAN-13 checksum: the weighted modulo-10 check digit, verified against the classic "4006381333931" worked example (a 375g box of Kellogg's Corn Flakes, the example used throughout the barcode literature) and several independently generated test values.
• EAN-13 parity: the left-hand odd/even (L/G) parity pattern for all ten possible leading digits, each verified against an exact, independently computed 95-module bit pattern.
• SVG well-formedness and injection safety: every rendered barcode is parsed back with System.Xml.Linq.XDocument in the test suite to confirm it is well-formed, and human-readable text and color options are fuzzed with <script> tags, quotes and ampersands to confirm they render as inert text, never as markup.
• Determinism: rendering the same pattern with the same options twice is asserted to produce byte-identical output.

Dependencies and AOT

Zero runtime NuGet dependencies. No System.Drawing, no native interop, no reflection anywhere in the encoding or rendering path, just plain data-driven lookup tables and string building. The library is fully trimmer and Native AOT safe.

License

MIT. See LICENSE.