Class: RQRCode::Export::SVG::Path

Inherits:
BaseOutputSVG show all
Defined in:
lib/rqrcode/export/svg.rb

Instance Attribute Summary

Attributes inherited from BaseOutputSVG

#result

Instance Method Summary collapse

Methods inherited from BaseOutputSVG

#initialize

Constructor Details

This class inherits a constructor from RQRCode::Export::SVG::BaseOutputSVG

Instance Method Details

#build(module_size, offset, color) ⇒ Object 



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# File 'lib/rqrcode/export/svg.rb', line 18

def build(module_size, offset, color)
  modules_array = @qrcode.modules
  matrix_width = matrix_height = modules_array.length + 1
  empty_row = [Array.new(matrix_width - 1, false)]
  edge_matrix = Array.new(matrix_height) { Array.new(matrix_width) }

  (empty_row + modules_array + empty_row).each_cons(2).with_index do |row_pair, row_index|
    first_row, second_row = row_pair

    # horizontal edges
    first_row.zip(second_row).each_with_index do |cell_pair, column_index|
      edge = case cell_pair
      when [true, false] then Edge.new column_index + 1, row_index, :left
      when [false, true] then Edge.new column_index, row_index, :right
      end

      (edge_matrix[edge.start_y][edge.start_x] ||= []) << edge if edge
    end

    # vertical edges
    ([false] + second_row + [false]).each_cons(2).each_with_index do |cell_pair, column_index|
      edge = case cell_pair
      when [true, false] then Edge.new column_index, row_index, :down
      when [false, true] then Edge.new column_index, row_index + 1, :up
      end

      (edge_matrix[edge.start_y][edge.start_x] ||= []) << edge if edge
    end
  end

  edge_count = edge_matrix.flatten.compact.count
  path = []

  while edge_count > 0
    edge_loop = []
    next_matrix_cell = edge_matrix.find(&:any?).find { |cell| cell&.any? }
    edge = next_matrix_cell.first

    while edge
      edge_loop << edge
      matrix_cell = edge_matrix[edge.start_y][edge.start_x]
      matrix_cell.delete edge
      edge_matrix[edge.start_y][edge.start_x] = nil if matrix_cell.empty?
      edge_count -= 1

      # try to find an edge continuing the current edge
      edge = edge_matrix[edge.end_y][edge.end_x]&.first
    end

    first_edge = edge_loop.first
    edge_loop_string = SVG_PATH_COMMANDS[:move]
    edge_loop_string += "#{first_edge.start_x} #{first_edge.start_y}"

    edge_loop.chunk(&:direction).to_a[0...-1].each do |direction, edges|
      edge_loop_string << "#{SVG_PATH_COMMANDS[direction]}#{edges.length}"
    end
    edge_loop_string << SVG_PATH_COMMANDS[:close]

    path << edge_loop_string
  end

  # Prefix hexadecimal colors unless using a named color (symbol)
  color = "##{color}" unless color.is_a?(Symbol)

  @result << %{<path d="#{path.join}" fill="#{color}" transform="translate(#{offset},#{offset}) scale(#{module_size})"/>}
end