Added printCol function.

lib/esc_pos_printer.dart

@@ -7,4 +7,5 @@
 library esc_pos_printer;
 
 export './src/enums.dart';
+export './src/exceptions.dart';
 export './src/printer.dart';

lib/src/enums.dart

@@ -31,3 +31,20 @@ class PosBeepDuration {
   static const beep400ms = PosBeepDuration._internal(8);
   static const beep450ms = PosBeepDuration._internal(9);
 }
+
+// class PosCol {
+//   const PosCol._internal(this.value);
+//   final int value;
+//   static const col1 = PosCol._internal(1);
+//   static const col2 = PosCol._internal(2);
+//   static const col3 = PosCol._internal(3);
+//   static const col4 = PosCol._internal(4);
+//   static const col5 = PosCol._internal(5);
+//   static const col6 = PosCol._internal(6);
+//   static const col7 = PosCol._internal(7);
+//   static const col8 = PosCol._internal(8);
+//   static const col9 = PosCol._internal(9);
+//   static const col10 = PosCol._internal(10);
+//   static const col11 = PosCol._internal(11);
+//   static const col12 = PosCol._internal(12);
+// }

lib/src/exceptions.dart

+class PosRowException implements Exception {
+  PosRowException(this._msg);
+  String _msg;
+
+  @override
+  String toString() => 'PosRowException: $_msg';
+}

lib/src/printer.dart

 import 'dart:io';
 import 'dart:typed_data';
+import 'package:hex/hex.dart';
 import 'commands.dart';
 import 'enums.dart';
+import 'exceptions.dart';
 
 /// Printer.
 class Printer {
@@ -57,6 +59,36 @@ class Printer {
     reset();
   }
 
+  void printRow(List<int> cols, List<String> data) {
+    final validRange = cols.every((val) => val >= 1 && val <= 12);
+    if (!validRange) {
+      throw PosRowException('Column width should be between 1..12');
+    }
+    final validSum = cols.fold(0, (int sum, cur) => sum + cur) == 12;
+    if (!validSum) {
+      throw PosRowException('Total columns width must be equal 12');
+    }
+    if (cols.length != data.length) {
+      throw PosRowException("Columns number doesn't equal to data number");
+    }
+
+    for (int i = 0; i < cols.length; ++i) {
+      final colInd = cols.sublist(0, i).fold(0, (int sum, cur) => sum + cur);
+      _printCol(colInd, data[i]);
+    }
+
+    _socket.writeln();
+  }
+
+  void _printCol(int i, String data) {
+    final int pos = i == 0 ? 0 : (512 * i / 11 - 1).round();
+    final hexStr = pos.toRadixString(16).padLeft(3, '0');
+    final hexPair = HEX.decode(hexStr);
+    // print('dec: $pos \t hex: $hexStr \t pair $hexPair');
+    _socket.add(Uint8List.fromList([0x1b, 0x24, hexPair[1], hexPair[0]]));
+    _socket.write(data);
+  }
+
   void beep(
       {int count = 3, PosBeepDuration duration = PosBeepDuration.beep450ms}) {
     if (count <= 0) {

pubspec.yaml

@@ -10,6 +10,7 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
+  hex: ^0.1.2
 
 dev_dependencies:
   flutter_test: