pattern_generator.rb

module GeoPattern
  class PatternGenerator
    DEFAULTS = {
      base_color: '#933c3c'
    }

    FILL_COLOR_DARK  = "#222"
    FILL_COLOR_LIGHT = "#ddd"
    STROKE_COLOR     = "#000"
    STROKE_OPACITY   = 0.02
    OPACITY_MIN      = 0.02
    OPACITY_MAX      = 0.15

    private

    attr_reader :opts, :hash, :svg

    public

    def initialize(string, opts={})
      @opts       = DEFAULTS.merge(opts)
      @hash       = Digest::SHA1.hexdigest string
      @svg        = SVG.new

      generate_background
      generate_pattern
    end

    def svg_string
      svg.to_s
    end
    alias_method :to_s, :svg_string

    def base64_string
      Base64.strict_encode64(svg_string)
    end

    def uri_image
      "url(data:image/svg+xml;base64,#{base64_string});"
    end

    def generate_background
      color = if opts[:color]
                PatternHelpers.html_to_rgb(opts[:color])
              else
                PatternHelpers.html_to_rgb_for_string(hash, opts[:base_color])
              end

      svg.rect(0, 0, "100%", "100%", "fill" => color)
    end

    def generate_pattern
      puts SVG.as_comment('Using generator key is deprecated as of 1.3.1') if opts.key? :generator

      requested_patterns = (Array(opts[:generator]) | Array(opts[:patterns])).flatten.compact

      validator = PatternValidator.new
      validator.validate(requested_patterns)

      sieve = PatternSieve.new
      patterns = sieve.fetch(requested_patterns)

      generator = patterns[[PatternHelpers.hex_val(hash, 20, 1), patterns.length - 1].min]

      # Instantiate the generator with the needed references
      # and render the pattern to the svg object
      generator.new(svg, hash).render_to_svg
    end
  end
end