Region calculator using ImageMagick's convert command

im-text-region.rb

#!/usr/bin/env ruby

# im-text-region.rb - Region calculator using ImageMagick's convert command
#   by takehikom

# ruby $S/priv/rb/im-text-region.rb
# ruby $S/priv/rb/im-text-region.rb '和歌山' Meiryo-UI-Regular

class TextRegion
  def initialize(opt = {})
    @debug = opt[:debug] #|| true

    @str = opt[:str] || "-|-"
    @font = opt[:font] || "Liberation-Sans-Regular"
    @pointsize = opt[:pointsize] || 48
    @basename = opt[:basename] || setup_basename
    @direction = opt[:direction] || "center"

    @xpm_width = @pointsize * @str.length
    @xpm_height = @pointsize
    @region = [0, 0, 100, 100] # x1,y1,x2,y2

    setup_region
  end

  def setup_basename
    require "tempfile"
    t = Tempfile.open("tmsr")
    @basename = t.path
    puts "basename: #{@basename}" if @debug
    t.close!

    @basename
  end

  def setup_region
    init_xpm_size
    create_xpm
    analyze_xpm
  end

  def init_xpm_size
    ext = 2

    command = "convert -debug annotate xc:" +
      " -font %s -pointsize %d -annotate 0 '%s'" % [@font, @pointsize, @str] +
      " null: 2>&1 | grep Metrics:"
    puts command if @debug
    result = `#{command}`
    if /width:\s*(\d*(\.\d*)?)/ =~ result
      @xpm_width = $1.to_f.ceil.to_i + ext
    else
      raise "#{command} --- \"width:\" not found"
    end
    if /height:\s*(\d*(\.\d*)?)/ =~ result
      @xpm_height = $1.to_f.ceil.to_i + ext
    else
      raise "#{command} --- \"height:\" not found"
    end

    puts "xpm_image: #{@xpm_width}x#{@xpm_height}" if @debug
  end

  def create_xpm
    @xpmfile = @basename + ".xpm"
    command = "convert -size %dx%d xc:white" % [@xpm_width, @xpm_height] +
      " -fill black -font %s -pointsize %d" % [@font, @pointsize] +
      " -draw \"text %d,%d \'%s\'\"" % [0, @pointsize, @str] +
      " -colors 2 %s" % @xpmfile
    puts command if @debug
    system command
    if !test(?f, @xpmfile)
      raise "#{@xpmfile} not created"
    end
  end

  def analyze_xpm
    @color = [] # [[" ", "#067D067D067D"], [".", "#FDE6FDE6FDE6"]]
    @pixel = [] # ["...", "...", ...]
    open(@xpmfile) do |f_in|
      f_in.each_line do |line0|
        next unless /^\".*\",?/ =~ line0
        line = line0.strip.sub(/\"/, "").sub(/\",?/, "")
        next if /(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/ =~ line
        if /(.) c / =~ line
          @color << [$1, $']
        else
          @pixel << line
        end
      end
    end

    if @color.empty?
      raise "#{@xpmfile}: color not specified."
    elsif @color.length != 2
      raise "#{@xpmfile}: not a B/W image."
    elsif @pixel.empty?
      raise "#{@xpmfile}: image not specified."
    end

    if @debug
      puts "image: #{@pixel[0].length}x#{@pixel.length}"
      puts "color:"
      @color.each do |item|
        puts "  #{item[0]} => #{item[1]}"
      end
    end

    c_black, c_white = @color.
      sort_by { |item| item.last }.
      map { |item| item.first }
    puts "  black => \"#{c_black}\"" if @debug
    puts "  white => \"#{c_white}\"" if @debug

    x1 = @pixel[0].length
    x2 = -1
    y1 = @pixel.length
    y2 = -1

    @pixel.each_with_index do |line, i|
      next if (pos = line.index(c_black)).nil?

      if y1 == @pixel.length
        y1 = i
      end

      y2 = i

      if pos < x1
        x1 = pos
      end

      pos2 = line.rindex(c_black, -1)
      if pos2 && pos2 > x2
        x2 = pos2
      end
    end

    if x2 == -1 || y2 == -1
      raise "#{@xpmfile}: seems to be all-white."
    end

    @region = [x1, y1, x2, y2]
    puts "region: (%d,%d)-(%d,%d)" % @region if @debug

    File.delete(@xpmfile) unless @debug
  end

  def test_draw
    @pngfile1 = @basename + "1.png"
    ofst_x, ofst_y = get_offset
    puts "ofst: (#{ofst_x},#{ofst_y})" if @debug
    command = "convert -size 400x400 xc:skyblue" +
      " -stroke blue -strokewidth 1 -draw \"line 0,200 400,200\" -draw \"line 200,0 200,400\"" +
      " -stroke none -fill black -font %s -pointsize %d" % [@font, @pointsize] +
      " -draw \"text %d,%d \'%s\'\"" % [200 + ofst_x, 200 + ofst_y, @str] +
      " -quality 90 %s" % @pngfile1
    puts command if @debug
    system command

    @pngfile2 = @basename + "2.png"
    command = "convert -size %dx%d xc:white" % [@xpm_width, @xpm_height] +
      " -fill black -font %s -pointsize %d" % [@font, @pointsize] +
      " -draw \"text %d,%d \'%s\'\"" % [0, @pointsize, @str] +
      " -fill none -stroke red -strokewidth 1" +
      " -draw \"rectangle %d,%d %d,%d\"" % @region +
      " -draw \"line %d,%d %d,%d\"" % @region +
      " -draw \"line %d,%d %d,%d\"" % @region.values_at(0, 3, 2, 1) +
      " -quality 90 %s" % @pngfile2
    puts command if @debug
    system command
  end

  def get_offset(dir = @direction)
    # "northwest" "north"  "northeast"
    # "west"      "center" "east"
    # "southwest" "south"  "southeast"

    x = (@region[0] + @region[2]) * 0.5 * (-1)
    y = (@region[1] + @region[3]) * 0.5 * (-1) + @pointsize

    if /west|left/i =~ dir
      x = @region[0] * (-1)
    elsif /east|right/i =~ dir
      x = @region[2] * (-1)
    end
    if /north|up/i =~ dir
      y = @region[1] * (-1) + @pointsize
    elsif /south|low/i =~ dir
      y = @region[3] * (-1) + @pointsize
    end

    [x, y]
  end

  alias :start :test_draw
end

if __FILE__ == $0
  str       = ARGV.shift || "-|-"
  font      = ARGV.shift || "Liberation-Sans-Regular"
  pointsize = (ARGV.shift || 48).to_i
  basename  = ARGV.shift || "im-text-region"
  direction = ARGV.shift || "center"
  TextRegion.new(:str       => str,
                 :font      => font,
                 :pointsize => pointsize,
                 :basename  => basename,
                 :direction => direction).start
end