Merge pull request #3 from mtking2/v0.1.2

ASCII compression

CHANGELOG.md

@@ -2,10 +2,14 @@
 
 * Your contribution here.
 
+### v0.1.2 (2019/10/10)
+
+* [#3](https://github.com/mtking2/img2zpl/pull/3): Add ASCII compression to conversion - [@mtking2](https://github.com/mtking2).
+
 ### v0.1.1 (2019/10/09)
 
-* [#2](https://github.com/mtking2/img2zpl/pull/2): Rename primary conversion method `.zpl` --> `.to_zpl` [@mtking2](https://github.com/mtking2).
+* [#2](https://github.com/mtking2/img2zpl/pull/2): Rename primary conversion method `.zpl` --> `.to_zpl` - [@mtking2](https://github.com/mtking2).
 
 ### v0.1.0 (2019/10/08)
-* [#1](https://github.com/mtking2/img2zpl/pull/1): Add functioning algorithm [@mtking2](https://github.com/mtking2).
+* [#1](https://github.com/mtking2/img2zpl/pull/1): Add functioning algorithm - [@mtking2](https://github.com/mtking2).
 * Initial public release - [@mtking2](https://github.com/mtking2).

Gemfile

@@ -3,6 +3,7 @@ source 'https://rubygems.org'
 group :development, :test do
   gem 'byebug'
   gem 'pry'
+  gem 'pry-nav'
 end
 
 gemspec

lib/img2zpl/image.rb

@@ -1,12 +1,11 @@
 class Img2Zpl::Image < MiniMagick::Image
 
-  def to_zpl(black_threshold: 0.5)
+  def to_zpl(black_threshold: 0.5, compress: true)
     bytes_per_row = (width % 8).positive? ? (width / 8) + 1 : (width / 8)
     byte_count = bytes_per_row * height
     data, line, previous_line, byte = '', '', '', ''
 
     get_pixels.each do |row|
-
       row.each_with_index do |column, i|
         r, g, b = column.map(&:to_i)
         byte << ((r + g + b) > (black_threshold * 765) ? '0' : '1')
@@ -15,18 +14,48 @@ def to_zpl(black_threshold: 0.5)
           byte = ''
         end
       end
-      data << (line == previous_line ? ':' : line.gsub(/0+$/, ',').gsub(/F+$/, '!'))
+
+      data << if compress
+        (line == previous_line ? ':' : line.gsub(/0+$/, ',').gsub(/F+$/, '!'))
+      else
+        line
+      end
+
       previous_line = line
       line = ''
     end
 
-    "^FO0,0^GFA,#{byte_count},#{byte_count},#{bytes_per_row},#{data}^FS"
+    _compress(data) if compress
+    "^GFA,#{byte_count},#{byte_count},#{bytes_per_row},#{data}^FS"
   end
 
   private
 
   def _compression_map
-    # TODO: finish compression map
+    map = {}
+    start = 'G'.ord
+    19.times { |i| map[i + 1] = (start+i).chr }
+    start = 'g'.ord
+    (20..400).step(20).each_with_index { |i, j| map[i] = (start+j).chr }
+    map
+  end
+
+  def _reduce(n)
+    str = ''
+    counts = _compression_map.keys.sort.reverse
+    counts.each do |c|
+      if c <= n
+        str << (_compression_map[c])
+        n -= c
+      end
+    end
+    str
+  end
+
+  def _compress(data)
+    data.gsub!(/([\da-zA-Z])(\1+)/) do |m|
+      "#{_reduce(m.length)}#{$1}"
+    end
   end
 
 end

lib/img2zpl/version.rb

@@ -1,3 +1,3 @@
 module Img2Zpl
-  VERSION = '0.1.1'
+  VERSION = '0.1.2'
 end

spec/img2zpl/image_spec.rb

@@ -4,13 +4,68 @@
 
   subject { described_class.open('spec/fixtures/default.jpg') }
 
-  it 'inherits from the MiniMagick::Image class' do
+  it 'should inherit from the MiniMagick::Image class' do
     expect(described_class.respond_to?(:open)).to be true
     expect(described_class.respond_to?(:read)).to be true
     expect(subject.respond_to?(:to_zpl)).to be true
   end
 
-  it 'zpl method returns a string' do
+  it 'should have the compression map' do
+    map = subject.send(:_compression_map)
+    expect(map[1]).to eq 'G'
+    expect(map[2]).to eq 'H'
+    expect(map[3]).to eq 'I'
+    expect(map[4]).to eq 'J'
+    expect(map[5]).to eq 'K'
+    expect(map[6]).to eq 'L'
+    expect(map[7]).to eq 'M'
+    expect(map[8]).to eq 'N'
+    expect(map[9]).to eq 'O'
+    expect(map[10]).to eq 'P'
+    expect(map[11]).to eq 'Q'
+    expect(map[12]).to eq 'R'
+    expect(map[13]).to eq 'S'
+    expect(map[14]).to eq 'T'
+    expect(map[15]).to eq 'U'
+    expect(map[16]).to eq 'V'
+    expect(map[17]).to eq 'W'
+    expect(map[18]).to eq 'X'
+    expect(map[19]).to eq 'Y'
+    expect(map[20]).to eq 'g'
+    expect(map[40]).to eq 'h'
+    expect(map[60]).to eq 'i'
+    expect(map[80]).to eq 'j'
+    expect(map[100]).to eq 'k'
+    expect(map[120]).to eq 'l'
+    expect(map[140]).to eq 'm'
+    expect(map[160]).to eq 'n'
+    expect(map[180]).to eq 'o'
+    expect(map[200]).to eq 'p'
+    expect(map[220]).to eq 'q'
+    expect(map[240]).to eq 'r'
+    expect(map[260]).to eq 's'
+    expect(map[280]).to eq 't'
+    expect(map[300]).to eq 'u'
+    expect(map[320]).to eq 'v'
+    expect(map[340]).to eq 'w'
+    expect(map[360]).to eq 'x'
+    expect(map[380]).to eq 'y'
+    expect(map[400]).to eq 'z'
+  end
+
+  it 'should properly compress ASCII data' do
+    d1 = '00000000000000000000000000000000000000000000000000000000008'
+    d2 = '5555555555555ADDDDDDDDDDDDDDDDDDDDDDD'
+    d3 = '00000000FFFFFFFFFFFFFFFFFFFFFFC0000000000000000000007FFFFFFFFF'
+    subject.send(:_compress, d1)
+    subject.send(:_compress, d2)
+    subject.send(:_compress, d3)
+    expect(d1).to eq 'hX08'
+    expect(d2).to eq 'S5AgID'
+    expect(d3).to eq 'N0gHFCgG07OF'
+  end
+
+  it 'should return a string when calling .to_zpl' do
     expect(subject.to_zpl).to be_kind_of String
   end
 

spec/spec_helper.rb

@@ -14,6 +14,10 @@
 #
 # See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
 require 'img2zpl'
+require 'byebug'
+require 'pry'
+require 'pry-nav'
+
 
 RSpec.configure do |config|
   # rspec-expectations config goes here. You can use an alternate