# File lib/gd2/palette.rb, line 148
    def allocate(color)
      raise TypeError unless color.kind_of? Color
      c = SYM[:gdImageColorAllocateAlpha].call(@image.image_ptr,
        color.red, color.green, color.blue, color.alpha)[0]
      c == -1 ? raise(Palette::PaletteFullError, 'Palette is full') :
        get_color(c)
    end