rouge-ruby/rouge · error · RuntimeError

invalid color: #{color}

Error message

invalid color: #{color}

What it means

Error "invalid color: #{color}" thrown in rouge-ruby/rouge.

Source

Thrown at lib/rouge/formatters/terminal256.rb:138

        def escape(attrs)
          return '' if attrs.empty?
          "\e[#{attrs.join(';')}m"
        end

        def self.color_index(color)
          @color_index_cache ||= {}
          @color_index_cache[color] ||= closest_color(*get_rgb(color))
        end

        def self.get_rgb(color)
          color = $1 if color =~ /#([0-9a-f]+)/i
          hexes = case color.size
          when 3
            color.chars.map { |c| "#{c}#{c}" }
          when 6
            color.scan(/../)
          else
            raise "invalid color: #{color}"
          end

          hexes.map { |h| h.to_i(16) }
        end

        def self.closest_color(r, g, b)
          @@colors_cache ||= {}
          key = (r << 16) + (g << 8) + b
          @@colors_cache.fetch(key) do
            distance = MAX_DISTANCE

            match = 0

            xterm_colors.each_with_index do |(cr, cg, cb), i|
              d = (r - cr)**2 + (g - cg)**2 + (b - cb)**2
              next if d >= distance

              match = i

View on GitHub (pinned to bd7dad7b09)

When it happens

Trigger: Thrown at lib/rouge/formatters/terminal256.rb:138 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of rouge-ruby/rouge@bd7dad7b09 (2026-08-23). Data as JSON: /api/errors/e3da267d4d98ab4a. Report an issue: GitHub.