2 Usage

2.1 Function

procedure
(qr-write data
output_file_path
[ #:mode mode
#:error_level error_level
#:module_width module_width
#:color color
#:express? express?
#:express_path express_path]
#:output_type output_type) → void?
  data : (string?)
  output_file_path : (path-string?)
  mode : string? = "B"
  error_level : string? = "H"
  module_width : natural? = 5
  color : (cons/c string? string?) = '("black" . "white")
  express? : boolean? = #f
  express_path : path-string? = "imgfile + '.write.express'"
  output_type : (or/c 'png 'svg)

output qr code image to file.

color’s form is ’(front_color . background_color).

use color "transparent" to set transparent(background).

if output_type is png, can use color-database<%> , but hex color is all available in all formats, recommended.

procedure
(qr-read image_file_path
[ #:express? express?
#:express_path express_path]) → string?
  image_file_path : (path-string?)
  express? : boolean? = #f
  express_path : path-string? = "imgfile + '.read.express'"

read qr code image’s content, if failed, return "".

2.2 Example

#lang racket

(require simple-qr)

;; block's default width is 5

(qr-write "https://github.com/simmone" "normal.png")

(qr-write "https://github.com/simmone" "normal_color.png" #:color '("#ffbb33" . "#0d47a1"))

(qr-write "https://github.com/simmone" "normal_trans.png" #:color '("#9933CC" . "transparent"))

(qr-write "https://github.com/simmone" "small.png" #:module_width 2)

(qr-write "https://github.com/simmone" "large.png" #:module_width 10)

(printf "~a\n~a\n~a\n"
        (qr-read "normal.png")
        (qr-read "small.png")
        (qr-read "large.png"))

(printf "~a\n" (qr-read "damaged.png"))

(qr-write "https://github.com/simmone" "normal.svg" #:output_type 'svg)

(qr-write "https://github.com/simmone" "normal_color.svg" #:color '("#ffbb33" . "#0d47a1") #:output_type 'svg)

(qr-write "https://github.com/simmone" "normal_trans.svg" #:color '("#9933CC" . "transparent") #:output_type 'svg)

2.3 Png

(qr-write "https://github.com/simmone" "normal.png")

(qr-write "https://github.com/simmone" "normal_color.png" #:color '("#ffbb33" . "#0d47a1"))

(qr-write "https://github.com/simmone" "normal_trans.png" #:color '("#9933CC" . "transparent"))

(qr-write "https://github.com/simmone" "small.png" #:module_width 2)

(qr-write "https://github.com/simmone" "large.png" #:module_width 10)

2.4 SVG

(qr-write "https://github.com/simmone" "normal.svg" #:output_type 'svg)

(qr-write "https://github.com/simmone" "normal_color.svg" #:color '("#ffbb33" . "#0d47a1") #:output_type 'svg)

(qr-write "https://github.com/simmone" "normal_trans.svg" #:color '("#9933CC" . "transparent") #:output_type 'svg)

2.5 Read and Correct

(printf "~a\n" (qr-read "damaged.png"))

https://github.com/simmone

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