# Barcodes
[](https://crates.io/crates/barcodes)
[](https://docs.rs/barcodes)
[](LICENSE)
[]()
A **universal bar/QR code generation library** for Rust, supporting many symbologies.
Zero external dependencies, pure `no_std`, and **zero heap allocation** by default.
## Features
- **Zero heap allocation** by default — encoders write into a caller-provided
`&mut [bool]` buffer via [`encode_into`](#zero-allocation-core); pure `no_std`,
no `alloc` required
- Zero external dependencies (default)
- Optional `alloc` feature for owned-output convenience (`encode()` +
`to_svg_string()`)
- Optional image output (PNG, GIF, WebP) via `image` feature
- Supports 16+ barcode symbologies: linear, 2D, and postal
## Installation
Add `barcodes` to your `Cargo.toml`.
**Default (pure `no_std`, zero allocation):**
```toml
[dependencies]
barcodes = "0.2"
```
**With owned output + SVG string convenience (`alloc`):**
```toml
[dependencies]
barcodes = { version = "0.2", features = ["alloc"] }
```
**With image output (PNG/GIF/WebP — implies `std`):**
```toml
[dependencies]
barcodes = { version = "0.2", features = ["image"] }
```
## Zero-allocation core
Every encoder implements
[`BarcodeEncoder::encode_into`](https://docs.rs/barcodes/latest/barcodes/common/traits/trait.BarcodeEncoder.html),
which writes the symbol's modules into a caller-provided buffer and returns an
`Encoded` describing the written region — no heap, no `alloc`:
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::common::types::Encoded;
use barcodes::ean_upc::ean13::Ean13;
let mut buf = [false; 128]; // stack buffer, one bool per module
let Encoded::Linear { len, height } = Ean13::encode_into("5901234123457", &mut buf).unwrap()
else { unreachable!() };
let bars = &buf[..len]; // true = dark module, false = light
assert_eq!(bars.len(), 95);
let _ = height;
```
2D symbologies return `Encoded::Matrix { width, height }`; their modules fill
`buf[..width * height]` in row-major order.
Render to SVG without allocating via [`common::svg`](https://docs.rs/barcodes/latest/barcodes/common/svg/index.html),
which streams into any `core::fmt::Write` sink.
The generated SVG has a `viewBox` and `style="max-width:100%;height:auto"`, so it
keeps its intrinsic size but scales **down** to fit a narrower container while
preserving aspect ratio. To let it grow to fill a wider container, override with
CSS — `svg { width: 100%; height: auto; }`.
> The `alloc` feature adds the convenience `Encoder::encode()` (returning an
> owned `BarcodeOutput`) and `.to_svg_string()`. The examples below use it.
> **Upgrading from 0.1.x?** `encode()` / `to_svg_string()` now live behind the
> `alloc` feature. Enable `features = ["alloc"]` to keep the old code unchanged,
> or switch to the zero-allocation `encode_into` shown above. See
> [CHANGELOG.md](CHANGELOG.md#migration-from-01x).
## Supported symbologies
| QR Code (Model 2) | `barcodes::qrcode` | ✅ |
| EAN-13 | `barcodes::ean_upc::ean13` | ✅ |
| EAN-8 | `barcodes::ean_upc::ean8` | ✅ |
| UPC-A | `barcodes::ean_upc::upca` | ✅ |
| UPC-E | `barcodes::ean_upc::upce` | ✅ |
| Code 128 (A/B/C) | `barcodes::linear::code128` | ✅ |
| Code 39 | `barcodes::linear::code39` | ✅ |
| Code 93 | `barcodes::linear::code93` | ✅ |
| Codabar (NW-7) | `barcodes::linear::codabar` | ✅ |
| ITF (Interleaved 2 of 5) | `barcodes::linear::itf` | ✅ |
| GS1-128 | `barcodes::gs1::gs1_128` | ✅ |
| GS1 DataBar Omnidirectional | `barcodes::gs1::databar` | ✅ |
| PDF417 | `barcodes::twod::pdf417` | ✅ |
| Data Matrix (ECC 200) | `barcodes::twod::datamatrix` | ✅ |
| Aztec Code | `barcodes::twod::aztec` | ✅ |
| USPS Intelligent Mail (IMb) | `barcodes::postal::imb` | ✅ |
| Royal Mail RM4SCC | `barcodes::postal::rm4scc` | ✅ |
## Usage
### QR Code
QR implements [`BarcodeEncoder`](#zero-allocation-core) like every other
symbology, so the uniform zero-allocation API works too (defaults: ECC Medium,
automatic version and mask):
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::common::types::Encoded;
use barcodes::qrcode::QrCode;
let mut buf = [false; 177 * 177]; // fits the largest QR (version 40)
let Encoded::Matrix { width, height } =
QrCode::encode_into("https://example.com", &mut buf).unwrap()
else { unreachable!() };
// buf[y * width + x] == true → dark module
let _ = height;
```
Use `encode_text` directly when you need to control the error-correction level,
version range, or mask:
```rust
use barcodes::qrcode::{QrCode, QrCodeEcc, Version, EncodeTextOptions};
let mut outbuffer = vec![0u8; Version::MAX.buffer_len()];
let mut tempbuffer = vec![0u8; Version::MAX.buffer_len()];
let qr = QrCode::encode_text(
"Hello, World!",
&mut tempbuffer,
&mut outbuffer,
EncodeTextOptions {
ecl: QrCodeEcc::Low,
minversion: Version::MIN,
maxversion: Version::MAX,
mask: None,
boostecl: true,
},
).unwrap();
println!("Version: {}", qr.version().value());
```
### EAN-13
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::ean_upc::ean13::Ean13;
// 13 digits (check digit validated) or 12 digits (check digit auto-computed)
let output = Ean13::encode("5901234123457").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### UPC-A
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::ean_upc::upca::UpcA;
let output = UpcA::encode("012345678905").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### Code 128
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::linear::code128::Code128;
let output = Code128::encode("Hello, World!").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### Code 39
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::linear::code39::Code39;
let output = Code39::encode("HELLO WORLD").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### Code 93
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::linear::code93::Code93;
let output = Code93::encode("CODE93").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### Codabar (NW-7)
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::linear::codabar::Codabar;
// Digits and -$:/.+ ; A/B start/stop guards are added automatically
let output = Codabar::encode("1234567").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### ITF (Interleaved 2 of 5)
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::linear::itf::Itf;
let output = Itf::encode("12345678").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### GS1-128
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::gs1::gs1_128::Gs1_128;
let output = Gs1_128::encode("(01)12345678901231(10)ABC123").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### EAN-8
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::ean_upc::ean8::Ean8;
let output = Ean8::encode("96385074").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### UPC-E
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::ean_upc::upce::UpcE;
let output = UpcE::encode("04252614").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### GS1 DataBar Omnidirectional
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::gs1::databar::DataBar;
let output = DataBar::encode("0950110153001").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### PDF417
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::twod::pdf417::Pdf417;
let output = Pdf417::encode("Hello, PDF417!").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### Data Matrix
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::twod::datamatrix::DataMatrix;
let output = DataMatrix::encode("Hello DM").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### Aztec Code
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::twod::aztec::Aztec;
let output = Aztec::encode("HELLO AZTEC").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### USPS Intelligent Mail Barcode (IMb)
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::postal::imb::Imb;
let output = Imb::encode("01234567094987654321").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
### Royal Mail RM4SCC
```rust
use barcodes::common::traits::BarcodeEncoder;
use barcodes::postal::rm4scc::Rm4scc;
let output = Rm4scc::encode("EC1A1BB").unwrap();
let svg = output.to_svg_string();
println!("{svg}");
```
## Image Output
Enable the `image` feature to generate raster images (PNG, GIF, WebP).
```rust
// Requires `image` feature enabled
use barcodes::common::traits::BarcodeEncoder;
use barcodes::ean_upc::ean13::Ean13;
let output = Ean13::encode("5901234123457").unwrap();
let img = output.to_image(2); // module_size = 2px
img.save("ean13.png").unwrap();
```
For QR Code:
```rust
use barcodes::qrcode::{QrCode, QrCodeEcc, Version, EncodeTextOptions};
let mut outbuffer = vec![0u8; Version::MAX.buffer_len()];
let mut tempbuffer = vec![0u8; Version::MAX.buffer_len()];
let qr = QrCode::encode_text(
"Hello, World!",
&mut tempbuffer,
&mut outbuffer,
EncodeTextOptions {
ecl: QrCodeEcc::Low,
minversion: Version::MIN,
maxversion: Version::MAX,
mask: None,
boostecl: true,
},
).unwrap();
let img = qr.to_image(4); // module_size = 4px
img.save("qrcode.png").unwrap();
```
## `no_std` and features
This library is pure `no_std` by default and performs **no heap allocation** —
the default build does not even link `alloc`, so any accidental allocation is a
compile error.
| _(default)_ | zero-alloc `encode_into` + `core::fmt::Write` SVG | — |
| `alloc` | owned `encode()` → `BarcodeOutput`, `to_svg_string()` | — |
| `std` | `std::error::Error` for `EncodeError` | `alloc` |
| `image` | raster output `to_image()` (PNG/GIF/WebP) | `std` |
## Modules Overview
| `barcodes::common` | Shared traits, types, errors, and output helpers |
| `barcodes::qrcode` | QR Code Model 2 encoder |
| `barcodes::ean_upc` | EAN-13, EAN-8, UPC-A, UPC-E |
| `barcodes::linear` | Code 128, Code 39, Code 93, Codabar, ITF |
| `barcodes::gs1` | GS1-128, GS1 DataBar |
| `barcodes::twod` | PDF417, Data Matrix, Aztec Code |
| `barcodes::postal` | USPS IMb, Royal Mail RM4SCC |
## Contributing
Contributions are welcome! To get started:
1. Fork the repo
2. Create a feature branch
3. Run `cargo test` and `cargo clippy`
4. Submit a pull request
## License
MIT — see [LICENSE](LICENSE) for details.