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

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

Constant Summary collapse

DIR_UP =

Direction constants for edge representation Edges stored as [start_x, start_y, direction] arrays instead of Struct

0
DIR_DOWN = 
1
DIR_LEFT = 
2
DIR_RIGHT = 
3
DIR_DELTAS =

Pre-computed end coordinate deltas: [dx, dy] for each direction

[
  [0, -1], # UP
  [0, 1],  # DOWN
  [-1, 0], # LEFT
  [1, 0]   # RIGHT
].freeze
DIR_PATH_COMMANDS =

SVG path commands indexed by direction constant

["v-", "v", "h-", "h"].freeze

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, options = {}) ⇒ Object 



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# File 'lib/rqrcode/export/svg.rb', line 36

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

  modules_array = @qrcode.modules
  module_count = modules_array.length
  matrix_size = module_count + 1

  # Edge matrix stores arrays of [x, y, direction] tuples
  edge_matrix = Array.new(matrix_size) { Array.new(matrix_size) }
  edge_count = 0

  # Process horizontal edges (between vertically adjacent cells)
  (module_count + 1).times do |row_index|
    module_count.times do |col_index|
      above = row_index > 0 && modules_array[row_index - 1][col_index]
      below = row_index < module_count && modules_array[row_index][col_index]

      if above && !below
        # Edge going left at (col+1, row)
        x = col_index + 1
        y = row_index
        (edge_matrix[y][x] ||= []) << [x, y, DIR_LEFT]
        edge_count += 1
      elsif !above && below
        # Edge going right at (col, row)
        x = col_index
        y = row_index
        (edge_matrix[y][x] ||= []) << [x, y, DIR_RIGHT]
        edge_count += 1
      end
    end
  end

  # Process vertical edges (between horizontally adjacent cells)
  module_count.times do |row_index|
    (module_count + 1).times do |col_index|
      left = col_index > 0 && modules_array[row_index][col_index - 1]
      right = col_index < module_count && modules_array[row_index][col_index]

      if left && !right
        # Edge going down at (col, row)
        x = col_index
        y = row_index
        (edge_matrix[y][x] ||= []) << [x, y, DIR_DOWN]
        edge_count += 1
      elsif !left && right
        # Edge going up at (col, row+1)
        x = col_index
        y = row_index + 1
        (edge_matrix[y][x] ||= []) << [x, y, DIR_UP]
        edge_count += 1
      end
    end
  end

  path_parts = []

  # Track search position to avoid re-scanning from beginning
  search_y = 0
  search_x = 0

  while edge_count > 0
    # Find next non-empty cell, starting from last position
    start_edge = nil
    found_y = search_y
    found_x = search_x

    # Continue from where we left off
    (search_y...matrix_size).each do |y|
      start_col = (y == search_y) ? search_x : 0
      (start_col...matrix_size).each do |x|
        cell = edge_matrix[y][x]
        next unless cell && !cell.empty?

        start_edge = cell.first
        found_y = y
        found_x = x
        break
      end
      break if start_edge
    end

    # Update search position for next iteration
    search_y = found_y
    search_x = found_x

    # Build path string directly without intermediate edge_loop array
    path_str = String.new(capacity: 64)
    path_str << "M" << start_edge[0].to_s << " " << start_edge[1].to_s

    current_edge = start_edge
    current_dir = nil
    current_count = 0

    while current_edge
      ex, ey, edir = current_edge

      # Remove edge from matrix
      cell = edge_matrix[ey][ex]
      cell.delete(current_edge)
      edge_matrix[ey][ex] = nil if cell.empty?
      edge_count -= 1

      # Accumulate consecutive edges in same direction
      if edir == current_dir
        current_count += 1
      else
        # Flush previous direction
        path_str << DIR_PATH_COMMANDS[current_dir] << current_count.to_s if current_dir
        current_dir = edir
        current_count = 1
      end

      # Find next edge at end coordinates
      delta = DIR_DELTAS[edir]
      next_x = ex + delta[0]
      next_y = ey + delta[1]
      next_cell = edge_matrix[next_y]&.[](next_x)
      current_edge = next_cell&.first
    end

    # Don't output the last direction segment - close path instead
    path_str << "z"
    path_parts << path_str
  end

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