README.md

Go wrapper for zxing-cpp

This folder contains a cgo-based Go wrapper around the zxing-cpp C API (core/src/ZXingC.h).

The wrapper links against the native ZXing shared library built by this repo's CMake.

This wrapper must be considered experimental at this point. The API might change anytime. Suggestions for improvements are welcome.

Installation

The wrapper supports two build modes:

1. Installed mode (default): uses pkg-config (zxing.pc) and works with system packages.
2. Local mode: links directly against an in-tree CMake build (useful for CI).

Installed mode (default)

Install zxing-cpp locally or as development package first, for example:

• macOS: brew install zxing-cpp
• Debian/Ubuntu: apt install libzxing-dev

Then run:

cd wrappers/go
go test ./...

Local mode (no install, CI-friendly)

Build zxing-cpp from the repo root:

cmake -S . -B build
cmake --build build

Then run Go with the local link mode enabled:

cd wrappers/go
go test -tags zxing_local ./...

This mode expects the native library in build/core and headers in core/src.

In your Go code:

import "github.com/zxing-cpp/zxing-cpp/wrappers/go/zxingcpp"

Minimal reader example:

package main

import (
	"fmt"
	"image"
	"os"
	_ "image/jpeg"
	_ "image/png"

	"github.com/zxing-cpp/zxing-cpp/wrappers/go/zxingcpp"
)

func main() {
	f, err := os.Open("in.png")
	if err != nil {
		panic(err)
	}
	defer f.Close()

	img, _, err := image.Decode(f)
	if err != nil {
		panic(err)
	}

	barcodes, err := zxingcpp.ReadBarcodes(img)
	if err != nil {
		panic(err)
	}

	for _, bc := range barcodes {
		fmt.Println(bc.Format(), bc.Text())
		bc.Close()
	}
}

Minimal writer example:

bc, _ := zxingcpp.CreateBarcode("hello", zxingcpp.BarcodeFormatQRCode)
defer bc.Close()

img, _ := bc.ToImage(zxingcpp.WithScale(4)) // returns standard image.Image
svg, _ := bc.ToSVG(zxingcpp.WithHRT(true))  // returns string
_ = img
_ = svg

Demo programs

From wrappers/go:

# writer
go run ./demo/demo_writer TEXT FORMAT OUTFILE(.svg|.png)

# reader
go run ./demo/demo_reader IMAGE [FORMATS] [fast]

Notes

• ImageView is a non-owning view in the C++ API.
• ReadBarcodes accepts either image.Image or *ImageView.
• ToImage returns a standard Go image.Image (*image.Gray currently), not a wrapper around C memory.
• For advanced/zero-copy use cases, NewImageViewFromC can wrap a pointer to C-allocated memory.