#!/usr/bin/env ruby
# encoding: utf-8

 Myname = 'cvcolor'
Version = '1.02'

Help=
<<'DOC'
= cvcolor - convert color name or rgb to color name, hsv, rgb, and cmyk

= Synopsis
cvcolor [colorname...] ['redvalue greenvalue bluevalue'...]	

== Options
   -h              print this help and exit
   -H, --help      print full documentation and exit
   -V, --version   print version and exit

= Description
Given one or more color names, or quoted rgb triplets, cvcolor will print
their rgb, hsv, and cmyk values.

An unknown color name is matched against the color database and the any
matches are reported.

With no arguments, cvcolor will accept one color name or 3 numerical rgb
values per line. The rgb values must either be in the range 0..1 or in the
range ..255. cvcolor responds with the corresponding (nearest) color name
and the rgb, hsv, and cmyk values.

Colors are taken from |/etc/X11/rgb.txt|, but colors with spaces in their
names are skipped (they have capitalized duplicates without spaces).

= Examples
  $ cvcolor DarkOliveGreen OliveDrab '.1 .2 .3' '25 50 75'
  DarkOliveGreen
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.333 0.420 0.184           85 107  47      556b2f
  HSV:      82 0.561 0.420
  CMYK:  0.086 0.000 0.235 0.580
  
  OliveDrab
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.420 0.557 0.137          107 142  35      6b8e23
  HSV:      79 0.754 0.557
  CMYK:  0.137 0.000 0.420 0.443
  
  nearest color: DarkSlateGray
  distance:      1.93%
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.100 0.200 0.300           26  51  77      1a334d
  HSV:     210 0.667 0.300
  CMYK:  0.200 0.100 0.000 0.700
  
  nearest color: gray20
  distance:      1.93%
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.098 0.196 0.294           25  50  75      19324b
  HSV:     210 0.667 0.294
  CMYK:  0.196 0.098 0.000 0.706
  
  $ cvcolor drab
  unknown color
  I know about OliveDrab OliveDrab1 OliveDrab2 OliveDrab3 OliveDrab4
  
  $ cvcolor darkolivegreen
  Database: DarkOliveGreen
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.333 0.420 0.184           85 107  47      556b2f
  HSV:      82 0.561 0.420
  CMYK:  0.086 0.000 0.235 0.580
  
  $ cvcolor Blue
  Database: blue
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.541 0.169 0.886          138  43 226      8a2be2
  HSV:     271 0.810 0.886
  CMYK:  0.345 0.718 0.000 0.114
  
  $ cvcolor '.1 .2. .3'
  nearest color: DarkSlateGray
  distance:      1.93%
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.100 0.200 0.300           26  51  77      1a334d
  HSV:     210 0.667 0.300
  CMYK:  0.200 0.100 0.000 0.700
  
  $ cvcolor '25.5 51 76.5'
  nearest color: DarkSlateGray
  distance:      1.93%
         ________0-1____________    ___0-255___    __00-ff__
  RGB:   0.100 0.200 0.300           26  51  77      1a334d
  HSV:     210 0.667 0.300
  CMYK:  0.200 0.100 0.000 0.700

= Author
[Wybo Dekker](wybodekker@me.com)

= Copyright
Released under the [GNU General Public License](www.gnu.org/copyleft/gpl.html)
DOC

require 'optparse'
require 'colorize'

def warn(*m) mess :magenta,*m if $op.verbose; end
def Warn(*m) mess :magenta,*m; end
def die(*m) mess :red,*m; exit 1; end

# print colored string(s), 1 line per argument
def mess(color,*m)
   name = Myname + ': '
   m.each do |v|
      STDERR.puts "#{name}#{v}".__send__(color)
      name.gsub!(/./,' ')
   end
end

def help
  system("echo \"#{Help}\" | less -P#{Myname}-#{Version.tr('.','·')}")
end

# convert rgb to hsv
def hsv(r,g,b)
   min = [r,g,b].min
   max = [r,g,b].max
   delta = max - min
   return 0,0,max if delta == 0 # R == G == B => gray
   s = delta/max
   h = case max
      when r then (g - b)/delta		# between yellow and magenta
      when g then 2 + (b - r)/delta	# between cyan and yellow
      else 4 + (r - g)/delta		# between magenta and cyan
   end
   h *= 60
   h += 360 if h < 0
   return h.to_i,s,max
end

# convert hsv to rgb
def rgb(h,s,v)

   # deliver gray for s == 0
   return v,v,v if s == 0

   # degrees => sectors
   h %= 360
   h /= 60
   sector = h.to_i
   secfract = h - sector
   p = v * (1 - s)
   q = v * (1 - s * secfract)
   t = v * (1 - s * (1 - secfract))
   return case sector
      when 0 then [v,t,p]	# red       - yellow
      when 1 then [q,v,p]	# yellow    - green
      when 2 then [p,v,t]	# green     - lightblue
      when 3 then [p,q,v]	# lightblue - darkblue
      when 4 then [t,p,v]	# darkblue  - magenta
      else        [v,p,q]       # magenta   - red
   end   
end

# convert rgb to cmyk
def cmyk(r,g,b)
  c = 1 - r
  m = 1 - g
  y = 1 - b
  k = [c,m,y].min
  c = c - k
  m = m - k
  y = y - k
  return [c,m,y,k]
end

# convert cmyk to rgb
def cmyk2rgb(c,m,y,k)
  c += k
  m += k
  y += k
  return [1-c,1-m,1-y]
end

def cvcolor(color)
   color = color.chomp
   return if color == ''
   mindist = 10.0
   if color =~ /[a-z]/i # color name?
      if @colors[color]
         rgb = @colors[color]
         hsv = hsv(*rgb)
      else
         known = Array.new
         @colors.each { |k,v|
            if k.downcase == color.downcase 
               print "Database: "
               cvcolor(k)
               return
            end
            known.push k if k =~ /#{color}/i 
         }
         puts "unknown color"
         puts "I know about #{known.join(' ')}\n\n" if known.size > 0
         return
      end
   else # no: rgb values
      rgb = color.split.collect { |x| x.to_f }
      unless rgb.size == 3
         die "I need either 3 rgb values or a color name"
         return
      end
      if rgb.max > 1 
         prefix = "I assume your values are ranged between 0..255\n"
         die(prefix+"but then, any value > 255 is an error") if rgb.max > 255
         die(prefix+"but then, any value < 0 is an error") if rgb.min < 0
         rgb.map! { |x| x/=255 }
      else 
         prefix = "I assume your values are ranged between 0..1\n"
         die(prefix+"but then, any value > 1 is an error") if rgb.max > 1
         die(prefix+"but then, any value < 0 is an error") if rgb.min < 0
      end
      hsv = hsv(*rgb)
      mindist = 10.0
      @colors.each { |c,ar| # find nearest color
         d = 0
         for i in 0..2 do d += (ar[i]-rgb[i])**2 end
         if d < mindist
            color = c
            mindist = d
         end
      }
   end
   if mindist == 10.0
     printf("%s\n",color)
   else
     printf("nearest color: %s\n",color)
     printf("distance:      %4.2f%%\n",mindist*100)
   end
   printf("       ________0-1____________    ___0-255___    __00-ff__\n")
   printf("RGB: %7.3f %5.3f %5.3f          %3d %3d %3d      %02x%02x%02x\n",
      *(rgb + rgb.map { |v| (v*255).round }*2))
   printf("HSV: %7d %5.3f %5.3f\n", hsv[0].round,hsv[1],hsv[2])
   printf("CMYK: %6.3f %5.3f %5.3f %5.3f\n\n",*cmyk(*rgb))
end

OptionParser.new(
   banner = <<~EOD,
	#{Myname} - convert color name or rgb to color name, hsv, rgb, and cmyk\n
	Usage: #{Myname} [colorname...] ['redvalue greenvalue bluevalue'...]\n
	Options:
	EOD
   width = 15,
   indent = ''
) do |opts|

  opts.on('-h','print this help and exit') do
     puts opts.to_a.delete_if { |x| x =~ /—$/}
     exit
  end
  opts.on('-H','--help', 'print full documentation and exit') do
     help
     exit
  end
  opts.on('-V','--version', 'print version and exit') do
      puts Version
      exit
  end
  opts.on('-I','—') do
     system("instscript #{Myname}")
     exit
  end
  opts.parse!
end

rgb = "/etc/X11/rgb.txt"
File.exist?(rgb) or die("File #{rgb} not found")
@colors = Hash.new
open(rgb) do |f|
  f.readlines.each do |l|
    next if l =~ /rgb\.txt/ # first line
    r,g,b,c = l.strip.split($;,4)
    next if c =~ / / # no colors with spaces
    @colors[c] = [r,g,b].collect { |x| x.to_f/255.0 }
  end
end

if ARGV.size > 0
   ARGV.each { |color| cvcolor(color) }
else
   puts "enter color names, one per line",
               "or whitespace separated rgb values",
	       "3 per line (range: 0..1 or 0..255)",
               "stop with an empty line",""
   Signal.trap("SIGINT") { exit }
   while c = gets
      c.chomp!
      break if c.empty?
      cvcolor(c)
   end
end