RQRCode

https://github.com/whomwah/rqrcode
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RQRCode is a Ruby library for creating and rendering QR codes into various formats, adapted from...
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### Install dependencies and run benchmarks

Source: https://github.com/whomwah/rqrcode/blob/main/benchmark/README.md

Commands to install dependencies and run specific format benchmarks or all benchmarks. The all benchmarks run takes approximately 1-2 minutes.

```bash
# Install dependencies
bundle install

# Run specific format benchmarks
rake benchmark:svg
rake benchmark:png
rake benchmark:html
rake benchmark:ansi
rake benchmark:format_comparison

# Run all benchmarks (takes ~1-2 minutes)
rake benchmark:all
```

--------------------------------

### Install RQRCode manually

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

Install the rqrcode gem manually using the command line.

```bash
gem install rqrcode
```

--------------------------------

### Basic usage example

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-html.md

Generates a QR code and writes it to an HTML file with an accompanying stylesheet.

```ruby
require "rqrcode"

qrcode = RQRCode::QRCode.new("http://github.com/")
html = qrcode.as_html

# Use with a matching stylesheet
stylesheet = <<~CSS
  table { border-collapse: collapse; }
  td.black { width: 4px; height: 4px; background: #000; }
  td.white { width: 4px; height: 4px; background: #fff; }
CSS

File.write("/tmp/qrcode.html", "<style>#{stylesheet}</style>#{html}")
```

--------------------------------

### Basic SVG export example

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-svg.md

A simple example demonstrating how to generate a standalone SVG file from a QR code.

```ruby
require "rqrcode"

qrcode = RQRCode::QRCode.new("http://github.com/")
svg = qrcode.as_svg(
  color: "000",
  shape_rendering: "crispEdges",
  module_size: 11,
  standalone: true,
  use_path: true
)

File.write("/tmp/qrcode.svg", svg)
```

--------------------------------

### Run the RQRCode test suite

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

Commands to install dependencies and execute the test suite or specific specs.

```bash
$ bundle install
$ rake      # runs specs and standard:fix
$ rake spec # just runs the specs
```

--------------------------------

### Basic QR Code Initialization

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

A simple example demonstrating how to initialize a new RQRCode::QRCode instance with a URL string.

```ruby
require "rqrcode"

qr = RQRCode::QRCode.new("https://kyan.com")
# qr.qrcode is an RQRCodeCore::QRCode instance
```

--------------------------------

### Run RQRCode linting

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

Commands to install dependencies and run standardrb for code checking and fixing.

```bash
$ bundle install
$ rake standard # checks
$ rake standard:fix # fixes
```

--------------------------------

### Basic as_ansi example

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-ansi.md

Creates a QR code for a URL and outputs it as ANSI with default options. Requires the rqrcode gem.

```ruby
require "rqrcode"

qrcode = RQRCode::QRCode.new("http://github.com/")

ansi = qrcode.as_ansi(
  light: "\033[47m",
  dark: "\033[40m",
  fill_character: "  ",
  quiet_zone_size: 4
)

puts ansi
```

--------------------------------

### Basic RQRCode usage

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/rqrcode.md

Example showing how to access the version constant and generate an SVG representation of a QR code.

```ruby
require "rqrcode"

RQRCode::VERSION            # => "3.2.0"
qr = RQRCode::QRCode.new("hello")
qr.as_svg                   # => SVG string
```

--------------------------------

### Install RQRCode via Gemfile

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

Add the rqrcode gem to your application's Gemfile.

```ruby
gem "rqrcode", "~> 3.0"
```

--------------------------------

### Custom colors and characters example

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-ansi.md

Shows custom ANSI colors (red light, blue dark), single-space fill character, and standard quiet zone. Also demonstrates reading back the ANSI string and saving it to a file.

```ruby
require "rqrcode"

qrcode = RQRCode::QRCode.new("hello", level: :m)

# red background light cells, blue background dark cells, single-space cells,
# standard 4-module quiet zone
puts qrcode.as_ansi(
  light: "\033[41m",          # red
  dark: "\033[44m",           # blue
  fill_character: " ",
  quiet_zone_size: 4
)

# Read back / save
text = qrcode.as_ansi
File.write("/tmp/qrcode.ansi", text)
```

--------------------------------

### RQRCodeCore::QRCode#initialize

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/rqrcode-core.md

Creates a new RQRCodeCore::QRCode instance. Accepts data as a String, an Array of Hashes with :data and :mode keys, or a QRSegment. Options include level, max_size, size, and mode. Runs the full encoding pipeline.

```APIDOC
## RQRCodeCore::QRCode#initialize

### Description
Creates a new RQRCodeCore::QRCode instance. Accepts data as a String, an Array of Hashes with :data and :mode keys, or a QRSegment. Options include level, max_size, size, and mode. Runs the full encoding pipeline.

### Method
Constructor

### Signature
```ruby
def initialize(data, *args)
```

### Parameters
#### data (String | Array<Hash> | QRSegment) - Required
- String: encoded as a single segment using options[:mode] (auto-detected from content otherwise).
- Array: every element must be a Hash with both :data and :mode keys; each becomes a QRSegment (multi-segment mode).
- QRSegment: used directly.
- Anything else raises QRCodeArgumentError.

#### *args (*) - Optional
A trailing Hash of options (extracted by extract_options!). Supported keys below.

### Options
- **level** (Symbol) - Optional - Default: :h - Error correction level: :l (7% restorable), :m (15%), :q (25%), :h (30%). Unknown symbols raise QRCodeArgumentError.
- **max_size** (Integer) - Optional - Default: RQRCodeCore::QRUtil.max_size (= 40) - Maximum allowed QR version. Passed as the recursion limit to minimum_version.
- **size** (Integer) - Optional - Default: smallest version that fits the data - Explicit QR version (1-40). size > max_size raises QRCodeArgumentError.
- **mode** (Symbol) - Optional - Default: auto (:number, :alphanumeric, or :byte_8bit depending on data) - Encoding mode for String data only: :number, :alphanumeric, :byte_8bit. Ignored for Array/QRSegment input.

### Return
A fully-encoded RQRCodeCore::QRCode. Construction runs the whole encoding pipeline: make -> prepare_common_patterns (position probes, alignment, timing) -> mask-pattern search over 8 patterns with QRUtil.get_lost_points -> map_data.

### Throws
RQRCodeCore::QRCodeArgumentError and RQRCodeCore::QRCodeRunTimeError - full catalog in errors.md.
```

--------------------------------

### Inline usage in a Rails view

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-html.md

Example of rendering the QR code directly within a Rails view template.

```ruby
# app/views/... — assuming @qr = RQRCode::QRCode.new(url)
<%= @qr.as_html.html_safe %>
```

--------------------------------

### new(string, *args)

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

Constructor for RQRCode::QRCode. Creates a new QR code instance by wrapping RQRCodeCore::QRCode with the given data and options.

```APIDOC
## new(string, *args)

### Description
Creates a new RQRCode::QRCode instance. The constructor forwards the data and options to RQRCodeCore::QRCode.new.

### Method
Constructor

### Signature
`RQRCode::QRCode.new(string, *args)`

### Parameters
- **string** (String | Array | RQRCodeCore::QRSegment) - Required - Data to encode: a String, an Array of Hashes with :data and :mode keys (multi-segment), or a QRSegment instance.
- **args** (*) - Optional - Optional positional argument: a single options Hash. Any trailing Hash is extracted and forwarded to RQRCodeCore::QRCode.new.

### Return
A new RQRCode::QRCode wrapping a RQRCodeCore::QRCode.

### Throws
Does not raise itself; forwards to RQRCodeCore::QRCode.new, which raises RQRCodeCore::QRCodeArgumentError (unknown error-correction level, invalid data type, oversized :size) and RQRCodeCore::QRCodeRunTimeError (data longer than maximum capacity).

### Example
```ruby
require "rqrcode"

qr = RQRCode::QRCode.new("https://kyan.com")
# qr.qrcode is an RQRCodeCore::QRCode instance
```

### Example with options and multi-segment data
```ruby
require "rqrcode"

qr = RQRCode::QRCode.new("QRCODE", size: 5, mode: :alphanumeric)
qr.qrcode.version # => 5
qr.qrcode.mode    # => :mode_alpha_numk

multi = RQRCode::QRCode.new([
  { data: "foo", mode: :byte_8bit },
  { data: "BAR1", mode: :alphanumeric }
])
multi.qrcode.multi_segment? # => true
```

### Example error handling
```ruby
require "rqrcode"

begin
  qr = RQRCode::QRCode.new("data", level: :z) # invalid correction level
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "Unknown error correction level `:z`"
end

begin
  qr = RQRCode::QRCode.new("data", level: :l, size: 41) # beyond max version 40
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "Given size greater than maximum possible size of 40"
end
```
```

--------------------------------

### QR Code Error Handling

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

Examples of catching RQRCodeCore::QRCodeArgumentError when providing invalid correction levels or invalid sizes.

```ruby
require "rqrcode"

begin
  qr = RQRCode::QRCode.new("data", level: :z) # invalid correction level
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "Unknown error correction level `:z`"
end

begin
  qr = RQRCode::QRCode.new("data", level: :l, size: 41) # beyond max version 40
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "Given size greater than maximum possible size of 40"
end
```

--------------------------------

### QR Code with Options and Multi-segment Data

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

Demonstrates passing configuration options and using an array of hashes to define multi-segment QR code data.

```ruby
require "rqrcode"

# Options are forwarded to rqrcode_core
qr = RQRCode::QRCode.new("QRCODE", size: 5, mode: :alphanumeric)
qr.qrcode.version # => 5
qr.qrcode.mode    # => :mode_alpha_numk

# Multi-segment: array of hashes with data: and mode: keys
multi = RQRCode::QRCode.new([
  { data: "foo", mode: :byte_8bit },
  { data: "BAR1", mode: :alphanumeric }
])
multi.qrcode.multi_segment? # => true
```

--------------------------------

### inspect method

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/rqrcode-core.md

Returns a compact one-line summary of the QRCodeCore object state.

```ruby
def inspect
  "QRCodeCore: @data='#{@data}', @error_correct_level=#{@error_correct_level}, @version=#{@version}, @module_count=#{@module_count}"
end
```

--------------------------------

### as_png - AsPngOptions

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/types.md

Options for RQRCode::QRCode#as_png. Controls PNG rendering, including colors, sizing, and save constraints.

```APIDOC
## as_png - AsPngOptions

### Description
Options for RQRCode::QRCode#as_png. Controls PNG rendering, including colors, sizing, and save constraints.

### Options
- **fill** (ChunkyPNG color arg | Array) - Optional - Background color; Arrays (e.g. [r, g, b(, a)]) are splatted into ChunkyPNG::Color. Default: "white".
- **color** (ChunkyPNG color arg | Array) - Optional - Foreground color; same accepted inputs. Default: "black".
- **file** (String | false) - Optional - Save path; when present, image is saved and save constraints apply. Default: false.
- **size** (Integer) - Optional - Google-style total size; presence selects Google sizing. Default: 120.
- **border_modules** (Integer) - Optional - Border width in modules (Google sizing); also used as the border-module count in original sizing. Default: 4.
- **module_px_size** (Integer) - Optional - Pixels per module (original sizing). Default: 6.
- **resize_gte_to** (Integer | false) - Optional - Original sizing: derive module size so image is >= this size. Default: false.
- **resize_exactly_to** (Integer | false) - Optional - Original sizing: resize final image to exactly this square size. Default: false.
- **color_mode** (Integer) - Optional - Save constraint (only with file:). Default: ChunkyPNG::COLOR_GRAYSCALE.
- **bit_depth** (Integer) - Optional - Save constraint, indexed images (only with file:). Default: 1.
- **interlace** (Boolean) - Optional - Save constraint (only with file:). Default: omitted.
- **compression** (Integer 0-9 | Zlib constant) - Optional - Save constraint (only with file:). Default: omitted.

### Example
```ruby
{
  fill: ChunkyPNG::ColorArg | Array,   # default "white"
  color: ChunkyPNG::ColorArg | Array,  # default "black"
  file: String | false,                # default false
  size: Integer,                       # default 120
  border_modules: Integer,             # default 4
  module_px_size: Integer,             # default 6
  resize_gte_to: Integer | false,      # default false
  resize_exactly_to: Integer | false,  # default false
  color_mode: Integer,                 # default ChunkyPNG::COLOR_GRAYSCALE
  bit_depth: Integer,                  # default 1
  interlace: Boolean,                  # default: omitted (ChunkyPNG default)
  compression: Integer | Zlib const    # default: omitted (ChunkyPNG default)
}
```

### Accepted by
RQRCode::QRCode#as_png
```

--------------------------------

### Generate QR code string representation

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

Example usage of the #to_s method to render a QR code as a string with custom dark and light characters and quiet zone padding.

```ruby
require "rqrcode"

qr = RQRCode::QRCode.new("hello", size: 2)
puts qr.to_s
puts qr.to_s(dark: "@", light: ".")
puts qr.to_s(dark: "##", light: "  ", quiet_zone_size: 2)
```

--------------------------------

### Basic QR code generation

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

Create a basic QR code instance and output it as a string.

```ruby
require "rqrcode"

qr = RQRCode::QRCode.new("https://kyan.com")

puts qr.to_s
# to_s( dark: "x", light: " " ) # defaults
```

--------------------------------

### as_html instance method implementation

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-html.md

The core method that iterates through the QR code modules and constructs the HTML table string.

```ruby
def as_html
  qr = @qrcode
  module_count = qr.module_count

  estimated_size = (module_count * module_count * 26) + (module_count * 9) + 15
  result = String.new(capacity: estimated_size)

  result << TABLE_OPEN
  module_count.times do |row_index|
    result << TR_OPEN
    module_count.times do |col_index|
      result << (qr.checked?(row_index, col_index) ? TD_BLACK : TD_WHITE)
    end
    result << TR_CLOSE
  end
  result << TABLE_CLOSE

  result
end
```

--------------------------------

### RQRCode::QRCode.new

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/README.md

Creates a new QRCode instance with the given data and options. This is the main constructor for the RQRCode gem.

```APIDOC
## RQRCode::QRCode.new

### Description
Creates a new QRCode instance with the given data and options. This is the main constructor for the RQRCode gem.

### Method
new

### Endpoint
RQRCode::QRCode.new(data, options = {})

### Parameters
#### Path Parameters
- **data** (String) - Required - The data to encode into the QR code.

#### Query Parameters
- **size** (Integer) - Optional - The size of the QR code (default: 4).
- **level** (Symbol) - Optional - The error correction level (:l, :m, :q, :h).

### Request Example
```ruby
qr = RQRCode::QRCode.new("https://kyan.com", size: 8, level: :m)
```

### Response
#### Success Response (200)
- **qr** (RQRCode::QRCode) - The new QRCode instance.

#### Response Example
```ruby
#<RQRCode::QRCode:0x00007f...>
```
```

--------------------------------

### Access the RQRCode console

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

Command to launch the library console for interactive testing.

```bash
$ ./bin/console
```

--------------------------------

### as_png(options = {})

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

Generates a PNG image of the QR code. Returns a ChunkyPNG::Image, or a file path string when the `file:` option is provided.

```APIDOC
## as_png(options = {})

### Description
Generates a PNG image of the QR code. Returns a ChunkyPNG::Image, or a file path string when the `file:` option is provided.

### Method
as_png

### Parameters
- **options** (Hash) - Optional - Options for PNG generation, including `file:` to save to a file

### Returns
- **ChunkyPNG::Image** - PNG image object
- **String** - File path when `file:` option is given
```

--------------------------------

### Basic QR Code PNG Export

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-png.md

Demonstrates the basic usage of as_png to generate a QR code image and write it to a file.

```ruby
require "rqrcode"
require "chunky_png" # for constants only if needed

qrcode = RQRCode::QRCode.new("http://github.com/")
png = qrcode.as_png(
  bit_depth: 1,
  border_modules: 4,
  color_mode: ChunkyPNG::COLOR_GRAYSCALE,
  color: "black",
  fill: "white",
  size: 120
)

IO.binwrite("/tmp/github-qrcode.png", png.to_s)
```

--------------------------------

### RQRCode Quick Orientation

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/README.md

Demonstrates the basic usage of the RQRCode::QRCode class to generate a QR code and access its various rendering methods.

```ruby
require "rqrcode"

qr = RQRCode::QRCode.new("https://kyan.com", size: 8, level: :m)

qr.to_s                                   # => ASCII string of the matrix
qr.qrcode                                 # => RQRCodeCore::QRCode (encoding details)
qr.as_svg                                 # => SVG String
qr.as_png                                 # => ChunkyPNG::Image
qr.as_ansi                                # => String with ANSI color codes
qr.as_html                                # => HTML <table> String
```

--------------------------------

### as_png

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

The as_png method produces a PNG using the ChunkyPNG gem, returning a ChunkyPNG::Image instance. It supports options for fill and color, as well as ChunkyPNG constraints like color_mode, bit_depth, interlace, and compression. Two sizing algorithms are available: Google's Chart API inspired sizing and original sizing.

```APIDOC
## as_png

### Description
The will produce a PNG using the ChunkyPNG gem. The result will be a ChunkyPNG::Image instance.

### Method
as_png

### Parameters
#### Options
- **fill** (ChunkyPNG::Color) - Optional - Background color, defaults to 'white'. Use [] for multi args
- **color** (ChunkyPNG::Color) - Optional - Foreground color, defaults to 'black'. Use [] for multi args

When option :file is supplied you can use the following ChunkyPNG constraints:
- **color_mode** - Optional - The color mode to use. Use one of the ChunkyPNG::COLOR_* constants. (defaults to 'ChunkyPNG::COLOR_GRAYSCALE')
- **bit_depth** - Optional - The bit depth to use. This option is only used for indexed images. (defaults to 1 bit)
- **interlace** - Optional - Whether to use interlacing (true or false). (defaults to ChunkyPNG default)
- **compression** - Optional - The compression level for Zlib. This can be a value between 0 and 9, or a Zlib constant like Zlib::BEST_COMPRESSION (defaults to ChunkyPNG default)

There are two sizing algorithms.
* Original that can result in blurry and hard to scan images
* Google's Chart API inspired sizing that resizes the module size to fit within the given image size.

The Google one will be used when no options are given or when the new size option is used.

*Google Sizing*
- **size** - Optional - Total size of PNG in pixels. The module size is calculated so it fits. (defaults to 120)
- **border_modules** - Optional - Width of white border around the modules. (defaults to 4). -- DONT USE border_modules OPTION UNLESS YOU KNOW ABOUT THE QUIET ZONE NEEDS OF QR CODES --

*Original Sizing*
- **module_px_size** - Optional - Image size, in pixels.
- **border** - Optional - Border thickness, in pixels

It first creates an image where 1px = 1 module, then resizes. Defaults to 120x120 pixels, customizable by option.

### Request Example
```ruby
require "rqrcode"

qrcode = RQRCode::QRCode.new("http://github.com/")

# NOTE: showing with default options specified explicitly
png = qrcode.as_png(
  bit_depth: 1,
  border_modules: 4,
  color_mode: ChunkyPNG::COLOR_GRAYSCALE,
  color: "black",
  file: nil,
  fill: "white",
  module_px_size: 6,
  resize_exactly_to: false,
  resize_gte_to: false,
  size: 120
)

IO.binwrite("/tmp/github-qrcode.png", png.to_s)
```

### Response
#### Success Response
Returns a ChunkyPNG::Image instance.
```

--------------------------------

### QRSegment class implementation

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/rqrcode-core.md

The core implementation of the QRSegment class, showing initialization, size calculation, and writer selection.

```ruby
class QRSegment
  attr_reader :data, :mode

  def initialize(data:, mode: nil)
    @data = data
    @mode = QRMODE_NAME.dig(mode&.to_sym)

    # If mode is not explicitly found choose mode according to data type
    @mode ||= if RQRCodeCore::QRNumeric.valid_data?(@data)
      QRMODE_NAME[:number]
    elsif QRAlphanumeric.valid_data?(@data)
      QRMODE_NAME[:alphanumeric]
    else
      QRMODE_NAME[:byte_8bit]
    end
  end

  def size(version)
    4 + header_size(version) + content_size
  end

  def header_size(version)
    QRUtil.get_length_in_bits(QRMODE[mode], version)
  end

  def content_size
    chunk_size, bit_length, extra = case mode
    when :mode_number
      [3, QRNumeric::NUMBER_LENGTH[3], QRNumeric::NUMBER_LENGTH[data_length % 3] || 0]
    when :mode_alpha_numk
      [2, 11, 6]
    when :mode_8bit_byte
      [1, 8, 0]
    end

    (data_length / chunk_size) * bit_length + (((data_length % chunk_size) == 0) ? 0 : extra)
  end

  def writer
    case mode
    when :mode_number
      QRNumeric.new(data)
    when :mode_alpha_numk
      QRAlphanumeric.new(data)
    when :mode_multi
      QRMulti.new(data)
    else
      QR8bitByte.new(data)
    end
  end

  private

  def data_length
    data.bytesize
  end
end
```

--------------------------------

### as_png method definition

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-png.md

The as_png method signature and default options configuration.

```ruby
def as_png(options = {})
  default_img_options = {
    bit_depth: 1,
    border_modules: 4,
    color_mode: ChunkyPNG::COLOR_GRAYSCALE,
    color: "black",
    file: false,
    fill: "white",
    module_px_size: 6,
    resize_exactly_to: false,
    resize_gte_to: false,
    size: 120
  }

  googleis = options.length == 0 || !options[:size].nil?
  options = default_img_options.merge(options) # reverse_merge
  fill = ChunkyPNG::Color(*(options[:fill].is_a?(Array) ? options[:fill] : [options[:fill]]))
  color = ChunkyPNG::Color(*(options[:color].is_a?(Array) ? options[:color] : [options[:color]]))
  output_file = options[:file]
  module_px_size = nil
  border_px = nil
  png = nil

  if googleis
    ...
  else
    ...
  end
  ...
end
```

--------------------------------

### Render QR code as PNG

Source: https://github.com/whomwah/rqrcode/blob/main/README.md

The as_png method produces a ChunkyPNG::Image instance. It supports Google-inspired sizing or original sizing algorithms and various ChunkyPNG constraints.

```ruby
require "rqrcode"

qrcode = RQRCode::QRCode.new("http://github.com/")

# NOTE: showing with default options specified explicitly
png = qrcode.as_png(
  bit_depth: 1,
  border_modules: 4,
  color_mode: ChunkyPNG::COLOR_GRAYSCALE,
  color: "black",
  file: nil,
  fill: "white",
  module_px_size: 6,
  resize_exactly_to: false,
  resize_gte_to: false,
  size: 120
)

IO.binwrite("/tmp/github-qrcode.png", png.to_s)
```

--------------------------------

### RQRCode::QRCode.new / RQRCodeCore::QRCode.new

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/configuration.md

Constructor for creating a QR code object. Accepts a trailing Hash of options for configuration.

```APIDOC
## RQRCode::QRCode.new / RQRCodeCore::QRCode.new

### Description
Creates a QR code object with the given data and optional configuration options.

### Method
Constructor

### Parameters
#### Constructor Options
- **data** (String | Array<Hash with :data,:mode> | QRSegment) - Required (positional) - Payload to encode. Multi-segment via Hash array.
- **size** (Integer) - Optional - Explicit QR version (1-40). Default: smallest version that fits the data. Raises QRCodeArgumentError if > max_size.
- **max_size** (Integer) - Optional - Version ceiling; recursion limit for automatic sizing. Default: RQRCodeCore::QRUtil.max_size (40).
- **level** (Symbol) - Optional - Error correction level: :l (7%), :m (15%), :q (25%), :h (30%). Default: :h. Unknown values raise QRCodeArgumentError.
- **mode** (Symbol) - Optional - Encoding mode: :number, :alphanumeric, :byte_8bit. Default: auto based on content. Only used for String data.

### Example
```ruby
RQRCode::QRCode.new("Hello, world!", size: 5, level: :m)
```
```

--------------------------------

### #modules

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

Delegated method that returns the module matrix. Deprecated - use #qrcode.modules instead.

```APIDOC
## #modules

### Description
Delegated method that returns the module matrix. Deprecated - use #qrcode.modules instead.

### Method
`modules`

### Return
Array<Array<Boolean>> - `module_count` rows of `module_count` booleans; `true` = dark module, `false`/`nil` = light. `nil` cells occur during construction only; the finished matrix contains `true`/`false`.
```

--------------------------------

### as_png options

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/configuration.md

Configuration options for the as_png method. Options are merged over defaults via default_img_options.merge(options). Two sizing branches: Google-style when no options or size is present; original sizing otherwise.

```APIDOC
## as_png options

### Description
Options for the as_png method, merged over defaults via default_img_options.merge(options). Two sizing branches: Google-style when no options are given or size is present; original sizing otherwise.

### Parameters

#### Options
- **fill** (ChunkyPNG color arg | Array) - Optional - Background color; Array splatted into ChunkyPNG::Color. Default: "white".
- **color** (ChunkyPNG color arg | Array) - Optional - Foreground color. Default: "black".
- **file** (String | false) - Optional - Path; when set, the image is saved and color_mode/bit_depth/interlace/compression apply. Default: false.
- **size** (Integer) - Optional - Google-style total image size in pixels; presence selects the Google branch. Default: 120.
- **border_modules** (Integer) - Optional - Google-style border width in modules (also used as border-module count in original sizing). Default: 4.
- **module_px_size** (Integer) - Optional - Original sizing: pixels per module. Default: 6.
- **resize_gte_to** (Integer | false) - Optional - Original sizing: derive module size so the image is at least this many pixels. Default: false.
- **resize_exactly_to** (Integer | false) - Optional - Original sizing: resize final image to exactly this many pixels. Default: false.
- **color_mode** (Integer (ChunkyPNG constant)) - Optional - Save constraint (only with file). Default: ChunkyPNG::COLOR_GRAYSCALE.
- **bit_depth** (Integer) - Optional - Save constraint, indexed images (only with file). Default: 1.
- **interlace** (Boolean) - Optional - Save constraint; applied only if the key is present (only with file). Default: ChunkyPNG default.
- **compression** (Integer 0-9 | Zlib constant) - Optional - Save constraint; applied only if the key is present (only with file). Default: ChunkyPNG default.

### Notes
- Options are merged over defaults via default_img_options.merge(options).
- Two sizing branches: Google-style when no options are given or size is present; original sizing otherwise.
```

--------------------------------

### inspect

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/rqrcode-core.md

Returns a compact one-line summary of the QR code object, overriding the default verbose inspect output.

```APIDOC
## inspect

### Description
Returns a compact one-line summary of the QR code object, including data, error correction level, version, and module count.

### Method
inspect

### Return
String - compact one-line summary. Example: QRCodeCore: @data='hello', @error_correct_level=2, @version=1, @module_count=21.
```

--------------------------------

### Require RQRCode

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/README.md

The entry point for the RQRCode gem.

```ruby
require "rqrcode"
```

--------------------------------

### RQRCode::QRCode Constructor

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/qrcode.md

The initialize method used to create a new QR code instance by forwarding arguments to RQRCodeCore::QRCode.

```ruby
def initialize(string, *args)
  @qrcode = RQRCodeCore::QRCode.new(string, *args)
end
```

--------------------------------

### as_html options

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/configuration.md

The as_html method takes no arguments.

```APIDOC
## as_html options

### Description
The as_html method takes no arguments.

```

--------------------------------

### Rect#build method implementation

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-svg.md

The build method for the Rect backend, which generates a <rect> element for every dark module in the QR code.

```ruby
def build(module_size, options = {})
  color = options[:color]
  offset_x = options[:offset_x].to_i
  offset_y = options[:offset_y].to_i

  @qrcode.modules.each_index do |c|
    @qrcode.modules.each_index do |r|
      next unless @qrcode.checked?(c, r)

      x = r * module_size + offset_x
      y = c * module_size + offset_y
      @result << %(<rect width="#{module_size}" height="#{module_size}" x="#{x}" y="#{y}" fill="#{color}"/>)
    end
  end
end
```

--------------------------------

### as_html

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/export-html.md

Renders the QR code as an HTML table string. It takes no arguments and returns a String containing a table with one row per module row, using CSS classes 'black' and 'white' for dark and light modules respectively.

```APIDOC
## as_html

### Description
Renders the QR code as an HTML table string. It takes no arguments and returns a String containing a table with one row per module row, using CSS classes 'black' and 'white' for dark and light modules respectively.

### Method
as_html

### Endpoint
N/A (Ruby instance method)

### Parameters
None

### Return
String - a UTF-8-safe preallocated string containing an HTML table representation of the QR code.

### Example
```ruby
require "rqrcode"

qrcode = RQRCode::QRCode.new("http://github.com/")
html = qrcode.as_html

# Use with a matching stylesheet
stylesheet = <<~CSS
  table { border-collapse: collapse; }
  td.black { width: 4px; height: 4px; background: #000; }
  td.white { width: 4px; height: 4px; background: #fff; }
CSS

File.write("/tmp/qrcode.html", "<style>#{stylesheet}</style>#{html}")
```

### Notes
- The method is included in RQRCode::QRCode via `RQRCode::QRCode.include RQRCode::Export::HTML`.
- The output uses CSS classes 'black' and 'white' for cells; consumers must supply the CSS themselves.
- The method does not raise exceptions; it calls `RQRCodeCore::QRCode#checked?` which may raise `RQRCodeCore::QRCodeRunTimeError` for out-of-range coordinates, but iteration is bounded by module_count so this cannot trigger.
```

--------------------------------

### Define RQRCode module entry point

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/rqrcode.md

The top-level namespace declaration in lib/rqrcode.rb that requires all core components and export modules.

```ruby
# frozen_string_literal: true

module RQRCode
  require "rqrcode_core"
  require "rqrcode/qrcode"
  require "rqrcode/export"
  require "rqrcode/version"
end
```

--------------------------------

### RQRCodeCore::QRCode Constructor

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/api-reference/rqrcode-core.md

The constructor initializes the QR code by processing input data and options, determining the version, and executing the encoding pipeline.

```ruby
def initialize(data, *args)
  options = extract_options!(args)

  level = (options[:level] || :h).to_sym
  max_size = options[:max_size] || QRUtil.max_size

  @data = case data
  when String
    QRSegment.new(data: data, mode: options[:mode])
  when Array
    raise QRCodeArgumentError, "Array must contain Hashes with :data and :mode keys" unless data.all? { |seg| seg.is_a?(Hash) && %i[data mode].all? { |s| seg.key? s } }
    data.map { |seg| QRSegment.new(**seg) }
  when QRSegment
    data
  else
    raise QRCodeArgumentError, "data must be a String, QRSegment, or an Array"
  end
  @error_correct_level = QRERRORCORRECTLEVEL[level]

  unless @error_correct_level
    raise QRCodeArgumentError, "Unknown error correction level `#{level.inspect}`"
  end

  size = options[:size] || minimum_version(limit: max_size)

  if size > max_size
    raise QRCodeArgumentError, "Given size greater than maximum possible size of #{QRUtil.max_size}"
  end

  @version = size
  @module_count = @version * 4 + QRPOSITIONPATTERNLENGTH
  @modules = Array.new(@module_count)
  @data_list = multi_segment? ? QRMulti.new(@data) : @data.writer
  @data_cache = nil
  make
end
```

--------------------------------

### Catching rqrcode exceptions in consumer code

Source: https://github.com/whomwah/rqrcode/blob/main/_autodocs/errors.md

Demonstrates how to rescue RQRCodeCore::QRCodeArgumentError and RQRCodeCore::QRCodeRunTimeError when providing invalid inputs or exceeding capacity limits.

```ruby
require "rqrcode"

begin
  qr = RQRCode::QRCode.new(123)                    # not a String/QRSegment/Array
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "data must be a String, QRSegment, or an Array"
end

begin
  qr = RQRCode::QRCode.new([{ data: "foo" }])      # missing :mode key
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "Array must contain Hashes with :data and :mode keys"
end

begin
  qr = RQRCode::QRCode.new("hello", level: :x)     # unknown level
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "Unknown error correction level `:x`"
end

begin
  qr = RQRCode::QRCode.new("hello", size: 41)      # > max version
rescue RQRCodeCore::QRCodeArgumentError => e
  puts e.message # => "Given size greater than maximum possible size of 40"
end

begin
  qr = RQRCode::QRCode.new("x" * 10_000, level: :h) # too long for any version
rescue RQRCodeCore::QRCodeRunTimeError => e
  puts e.message # => "Data length exceed maximum capacity of version 40"
end

# Through the delegated API
core = RQRCode::QRCode.new("hi").qrcode
begin
  core.checked?(999, 0)
rescue RQRCodeCore::QRCodeRunTimeError => e
  puts e.message # => "Invalid row/column pair: 999, 0"
end
```
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