Module: Jsong

Defined in:
lib/jsong.rb,
lib/jsong/version.rb

Constant Summary collapse

DEFAULT = 
{
  version: '1.0',
  transparency: true,
  size: {},
  layers: [{
    default_color: {
      red: 0,
      green: 0,
      blue: 0,
      alpha: 255
    },
    pixels: []
  }]
}.freeze
VERSION = 
"0.4.0"

Class Method Summary collapse

Class Method Details

.encode_pixel(px) ⇒ ChunkyPNG::Color

Converts a single pixel hash to a chunky png pixel.

Parameters:

  • px (Hash<String => Integer>) —

    Hash containing red, green, blue and alpha values.

Returns:

  • (ChunkyPNG::Color) 


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# File 'lib/jsong.rb', line 96

def Jsong.encode_pixel(px)
  r, g = px['red'],  px['green']
  b, a = px['blue'], px['alpha']

  ChunkyPNG::Color.rgba(r, g, b, a)
end

.from_jsong(text, file_name, yaml: false) ⇒ nil

Converts JSON-G or YAML-G data to an image.

Parameters:

  • text (String) —

    Raw JSON-G or YAML-G data.

  • file_name (String) —

    Target file name.

  • yaml (true, false) (defaults to: false) —

    Set to true if the data is in YAML-G.

Returns:

  • (nil) 


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# File 'lib/jsong.rb', line 71

def Jsong.from_jsong(text, file_name, yaml: false)
  text = text.read if text.respond_to? :read
  data = if yaml; YAML.load text; else; JSON.parse text; end
  default_color = Jsong.encode_pixel data['layers'][-1]['default_color']
  w, h = data['size']['width'], data['size']['height']

  png = ChunkyPNG::Image.new(w, h, default_color)
  png.metadata['Title'] = data['comment']

  data['layers'].reverse.each do |layer|
    layer['pixels'].each do |px|
      x, y = px['position']['x'], px['position']['y']
      pixel = Jsong.encode_pixel px['color']
      png.set_pixel x, y, pixel
    end
  end

  png.save(file_name, :interlace => true)
end

.rrggbbaa_to_jsong(i) ⇒ Hash<String => Integer>

Converts an integer to JSON-G hash.

Parameters:

  • i (Integer) —

    Base 10 colour value in hex format RRGGBBAA.

Returns:

  • (Hash<String => Integer>) —

    Hash with red, green, blue and alpha values



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# File 'lib/jsong.rb', line 108

def Jsong.rrggbbaa_to_jsong(i)
  {
    red: (i / 16777216).floor,
    green: (i / 65536).floor & 0xFF,
    blue: (i / 256).floor & 0xFF,
    alpha: i & 0xFF
  }
end

.to_jsong(file_name, comment: nil, pixel_comment: nil, yaml: false) ⇒ String

Converts a PNG image to JSON-G or YAML-G.

Parameters:

  • comment (String) (defaults to: nil) —

    Optional global comment string.

  • pixel_comment (String) (defaults to: nil) —

    Optional comment string for every pixel.

  • yaml (true, false) (defaults to: false) —

    Set to true if you need YAML-G.

Returns:

  • (String) —

    JSON-G or YAML-G data.



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# File 'lib/jsong.rb', line 29

def Jsong.to_jsong(file_name, comment: nil, pixel_comment: nil, yaml: false)
  image = ChunkyPNG::Image.from_file file_name

  if comment.nil? && image.metadata['Title']
    comment = image.metadata['Title']
  elsif comment.nil?
    comment = 'Created with ruby Jsong gem'
  end

  data = DEFAULT.dup

  data[:comment] = comment
  data[:size][:width] = image.width
  data[:size][:height] = image.height

  image.pixels.each_slice(image.width).with_index do |arr, y|
    arr.each_with_index do |pixel, x|
      data[:layers][0][:pixels] << {
        position: {
          x: x,
          y: y
        },
        color: Jsong.rrggbbaa_to_jsong(pixel),
        comment: pixel_comment || 'A pixel'
      }
    end
  end

  if yaml
    data.to_yaml
  else
    data.to_json
  end
end