GS1 support

CHANGELOG.md

@@ -1,3 +1,7 @@
+## [0.2.0] - 2024-02-11
+
+- Support GS1 DataMatrix
+
 ## [0.1.1] - 2021-09-02
 
 - Fix PNG bgcolor

Gemfile

@@ -4,3 +4,4 @@ gemspec
 
 gem 'rake', '~> 13.0'
 gem 'minitest', '~> 5.0'
+gem 'debug'

Gemfile.lock

@@ -0,0 +1,40 @@
+PATH
+  remote: .
+  specs:
+    dmtx (0.2.0)
+      builder
+      chunky_png
+
+GEM
+  remote: https://rubygems.org/
+  specs:
+    builder (3.2.4)
+    chunky_png (1.4.0)
+    debug (1.9.1)
+      irb (~> 1.10)
+      reline (>= 0.3.8)
+    io-console (0.7.2)
+    irb (1.11.2)
+      rdoc
+      reline (>= 0.4.2)
+    minitest (5.22.2)
+    psych (5.1.2)
+      stringio
+    rake (13.1.0)
+    rdoc (6.6.2)
+      psych (>= 4.0.0)
+    reline (0.4.2)
+      io-console (~> 0.5)
+    stringio (3.1.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  debug
+  dmtx!
+  minitest (~> 5.0)
+  rake (~> 13.0)
+
+BUNDLED WITH
+   2.1.4

README.md

@@ -42,6 +42,13 @@ dmtx.width
 dmtx.height
 => 16
 
+dmtx.encoding
+=> :ascii
+
+dmtx.encoded_message
+=> [68, 105, 118, 111, 108, 122, 33, 67, 98, 100, 112, 111,
+    62, 103, 49, 93, 99, 53, 117, 202, 250, 186, 232, 14]
+
 # Generate SVG
 dmtx.to_svg
 => "<svg xmlns= ..."
@@ -67,3 +74,9 @@ dmtx.to_i
 # Binary representation
 dmtx.to_i.to_s(2)
 => "1010101010101010101110101000001111010111111101101001101011101001100110010100111010111011111100111001011001001000100010000111010110110001101111001011001001101011110000011111110010101101101010111001101001000000111100101000110110101110011100101111111111111111"
+
+# Choose encoding
+Dmtx::DataMatrix.new('Chunky Bacon', encoding: :txt)
+
+# GS1 DataMatrix
+Dmtx::DataMatrix.new("\x1d01095011010209171719050810ABCD1234\x1d2110", encoding: :gs1)

lib/dmtx.rb

@@ -1,7 +1,7 @@
 require_relative 'dmtx/version'
 require_relative 'dmtx/data_matrix'
-require_relative 'dmtx/gs1_data_matrix'
 
 module Dmtx
   class Error < StandardError; end
+  class EncodingError < Error; end
 end

lib/dmtx/data_matrix.rb

@@ -6,7 +6,7 @@
 
 module Dmtx
   class DataMatrix
-    attr_reader :width, :height
+    attr_reader :width, :height, :encoded_message, :encoding
 
     C40 = [230,
            31, 0, 0,
@@ -43,16 +43,26 @@ class DataMatrix
            64, 8,  0,
            90, 9, 51,
            255, 8,  0]
-
-    def initialize(msg, rect: false)
+
+    # See https://www.gs1.org/standards/gs1-datamatrix-guideline/25
+    FNC1 = 29
+    FNC1_CODEWORD = 232
+
+    DEFAULT_ENCODINGS = %i[ascii c40 txt x12 edifact base gs1].freeze
+    ENCODINGS = (%i[gs1] + DEFAULT_ENCODINGS).freeze
+
+    def initialize(msg, rect: false, encoding: nil)
       @m = []
       @width = 0
       @height = 0
-      encode(msg, rect)
+      raise ArgumentError, "illegal encoding #{encoding.inspect}" if encoding && !ENCODINGS.include?(encoding)
+      @encoding, @encoded_message = encode_message(msg, encoding)
+      raise EncodingError, "illegal payload" unless @encoded_message
+      encode(@encoded_message, rect)
     end
 
     def inspect
-      "#<#{self.class.name}:0x#{object_id.to_s(16)} #{width}x#{height}>"
+      "#<#{self.class.name}:0x#{object_id.to_s(16)} #{width}x#{height}@#{encoding}>"
     end
 
     def to_i
@@ -76,7 +86,6 @@ def to_svg(dim: 256, pad: 2, bgcolor: nil, color: '#000')
       y = height
       while y > 0
         y -= 1
-        d = 0
         x = width
         while x > 0
           x -= 1
@@ -139,6 +148,23 @@ def ascii_encode(t)
       end
       result
     end
+
+    def gs1_encode(t)
+      bytes, result = t.bytes, []
+      while c = bytes.shift
+        if !bytes.empty? && c > 47 && c < 58 && bytes.first > 47 && bytes.first < 58
+          result << (c - 48) * 10 + bytes.shift + 82
+        elsif c > 127
+          result << 235
+          result << ((c - 127) & 255)
+        elsif c == FNC1
+          result << FNC1_CODEWORD
+        else
+          result << c + 1
+        end
+      end
+      result
+    end
 
     def base_encode(t)
       bytes, result = t.bytes, [231]
@@ -204,18 +230,27 @@ def text_encode(t, s)
       result.concat ascii_encode(bytes[(i - cc)..-1].to_a.pack('C*')) if cc > 0 || i < l
       result
     end
-
-    def encodings(msg)
-      { ascii: ascii_encode(msg),
-        c40: text_encode(msg, C40),
-        txt: text_encode(msg, TEXT),
-        x12: text_encode(msg, X12),
-        edifact: edifact_encode(msg),
-        base: base_encode(msg) }
+
+    def c40_encode(t)
+      text_encode(t, C40)
+    end
+
+    def txt_encode(t)
+      text_encode(t, TEXT)
+    end
+
+    def x12_encode(t)
+      text_encode(t, X12)
+    end
+
+    def encode_message(msg, encoding)
+      (encoding ? [encoding] : DEFAULT_ENCODINGS)
+        .map { |name| [name, send("#{name}_encode", msg)] }
+        .reject { |_, encoded| encoded.empty? }
+        .min_by { |_, encoded| encoded.size }
     end
 
-    def encode(text, rct)
-      enc = encodings(text).values.reject(&:empty?).min_by(&:size)
+    def encode(enc, rct)
       el = enc.size
       nc = nr = 1
       j = -1

lib/dmtx/version.rb

@@ -1,3 +1,3 @@
 module Dmtx
-  VERSION = '0.1.1'
+  VERSION = '0.2.0'
 end

test/dmtx_test.rb

@@ -33,9 +33,9 @@ def test_generate_data_matrix_svg
 
   def test_gs1_data_matrix_encodings
     # See example 2 at https://www.gs1.org/standards/gs1-datamatrix-guideline/25#2-Encoding-data+2-3-Human-readable-interpretation-(HRI)
-    data = "#{Dmtx::GS1DataMatrix::FNC1}01095011010209171719050810ABCD1234#{Dmtx::GS1DataMatrix::FNC1}2110"
-    encodings = Dmtx::GS1DataMatrix.new(data).encodings(data)
-    assert_equal %i[asci], encodings.keys
-    assert_equal 232, encodings[:asci].first
+    data = "#{Dmtx::DataMatrix::FNC1.chr}01095011010209171719050810ABCD1234#{Dmtx::DataMatrix::FNC1.chr}2110"
+    dmtx = Dmtx::DataMatrix.new(data, encoding: :gs1)
+    assert_equal :gs1, dmtx.encoding
+    assert_equal 232, dmtx.encoded_message.first
   end
 end