README.Rmd

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# QRcode Generator for R <img src="man/figures/logo.svg" align="right" alt="A hexagon with the word qrcode and a qrcode linking to the DOI" width="120" />

A [QR code](https://en.wikipedia.org/wiki/QR_code) is a two-dimensional barcode developed by the Denso Wave company.

The current implementation handles three modes: numeric, alphanumeric and byte.
Kanji is currently not supported.
Please contact the maintainer if you need it.

- **Numeric**: only digits from 0 to 9
- **Alphanumeric**: all numeric characters, upper case `LETTERS`, and the characters `" "` (space), `"$"`, `"%"`, `"*"`, `"+"`, `"-"`, `"."`, `"/"` and `":"`
- **Byte**: All characters from the Latin 1 (ISO 8859-1) character set.

## Main functions

The main `qr_code()` function returns an object of the `qr_code` class.
This is a logical matrix with specific methods for printing and plotting.
The print version uses UTF-8 drawing symbols and the result depend on the font used.
For a better quality QR code it best to use `plot()` or `generate_svg()`.

```{r base}
library(qrcode)
code <- qr_code("QR CODE")
print(code)
```

```{r example, fig.path = "man/figures/", fig.alt = "A QR code displaying the value 'QR CODE'"}
plot(code)
```

```{r svg}
generate_svg(code, filename = "man/figures/qr.svg")
```

![A QR code displaying the value 'QR CODE'](man/figures/qr.svg)

## Installation

The `qrcode` package is available from CRAN, R universe and GitHub.

```{r eval = FALSE}
# install from CRAN
install.packages("qrcode")
# install from R universe
install.packages("qrcode", repos = "https://thierryo.r-universe.dev")
# install from GitHub use the remotes package
remotes::install_github("ThierryO/qrcode")
```

## Legacy code

The legacy function `qrcode_gen()` had several known bugs.
Because of these bugs, we re-implemented the code from scratch in version 0.1.4.
We created new functions.
The old functions are defunct since version 0.2.0.
We removed them in version 0.2.2.