# go-qrcode #
[](https://goreportcard.com/report/github.com/yeqown/go-qrcode)
[](https://pkg.go.dev/github.com/yeqown/go-qrcode/v2)
[](https://github.com/yeqown/go-qrcode/actions/workflows/go.yml) 
[](./LICENSE)
QR code (abbreviated from Quick Response Code) is the trademark for a type of matrix barcode (or two-dimensional barcode) first designed in 1994 for the automotive industry in Japan. A barcode is a machine-readable optical label that contains information about the item to which it is attached. A QR code uses four standardized encoding modes (numeric, alphanumeric, byte/binary, and kanji) to store data efficiently; extensions may also be used
### Features
- [x] Normally generate QR code across `version 1` to `version 40`.
- [x] Automatically analyze QR version by source text.
- [x] Specifying cell shape allowably with `WithCustomShape`, `WithCircleShape` (default is `rectangle`)
- [x] Specifying output file's format with `WithBuiltinImageEncoder`, `WithCustomImageEncoder` (default is `JPEG`)
- [x] Not only shape of cell, but also color of QR Code background and foreground color.
- [x] `WithLogoImage`, `WithLogoImageFilePNG`, `WithLogoImageFileJPEG` help you add an icon at the central of QR Code.
- [x] `WithBorderWidth` allows to specify any width of 4 sides around the qrcode.
- [x] `WebAssembly` support, check out the [Example](./example/webassembly/README.md) and [README](cmd/wasm/README.md) for more detail.
- [x] support Halftone QR Codes, check out the [Example](./example/with-halftone).
### Install
```sh
go get -u github.com/yeqown/go-qrcode/v2
```
### Quick Start
link to [CODE](./example/main.go)
```go
package main
import (
"github.com/yeqown/go-qrcode/v2"
"github.com/yeqown/go-qrcode/writer/standard"
)
func main() {
qrc, err := qrcode.New("https://github.com/yeqown/go-qrcode")
if err != nil {
fmt.Printf("could not generate QRCode: %v", err)
return
}
w, err := standard.New("../assets/repo-qrcode.jpeg")
if err != nil {
fmt.Printf("standard.New failed: %v", err)
return
}
// save file
if err = qrc.Save(w); err != nil {
fmt.Printf("could not save image: %v", err)
}
}
```
### Options
```go
const (
// EncModeNone mode ...
EncModeNone encMode = 1 << iota
// EncModeNumeric mode ...
EncModeNumeric
// EncModeAlphanumeric mode ...
EncModeAlphanumeric
// EncModeByte mode ...
EncModeByte
// EncModeJP mode ...
EncModeJP
)
// WithEncodingMode sets the encoding mode.
func WithEncodingMode(mode encMode) EncodeOption {}
const (
// ErrorCorrectionLow :Level L: 7% error recovery.
ErrorCorrectionLow ecLevel = iota + 1
// ErrorCorrectionMedium :Level M: 15% error recovery. Good default choice.
ErrorCorrectionMedium
// ErrorCorrectionQuart :Level Q: 25% error recovery.
ErrorCorrectionQuart
// ErrorCorrectionHighest :Level H: 30% error recovery.
ErrorCorrectionHighest
)
// WithErrorCorrectionLevel sets the error correction level.
func WithErrorCorrectionLevel(ecLevel ecLevel) EncodeOption {}
```
following are some shots:
### Built-in Writers
- [Standard Writer](./writer/standard/README.md), prints QRCode into file and stream
- [Terminal Writer](./writer/terminal/README.md), prints QRCode into terminal
Of course, you can also code your own writer, just implement [Writer](./writer/README.md) interface.
### Migrating from v1
`go-qrcode.v2` is a major upgrade from v1, and it is not backward compatible. `v2` redesigned
the API, and it is more flexible and powerful. Features are split into different modules (according to functionality).
- github.com/yeqown/go-qrcode/v2 **_core_**
- github.com/yeqown/go-qrcode/writer/standard **_writer/imageFile_**
- github.com/yeqown/go-qrcode/writer/terminal **_writer/terminal_**
Check [example/migrating-from-v1](./example/migrating-from-v1/main.go) for more details.
### Links
* [QRCode Tourist](https://www.thonky.com/qr-code-tutorial/)
* [QRCode Wiki](https://en.wikipedia.org/wiki/QR_code)
* [二维码详解 (QRCode analysis in CN-zh)](https://zhuanlan.zhihu.com/p/21463650)
* [数据编码 (How to encode data payload in QRCode in CN-zh)](https://zhuanlan.zhihu.com/p/25432676)
