Added Columns property in order to get extra commands based off it

ESCPOS_NET/Emitters/BaseCommandEmitter/CharacterCommands.cs

@@ -1,9 +1,12 @@
 using ESCPOS_NET.Emitters.BaseCommandValues;
+using System;
 
 namespace ESCPOS_NET.Emitters
 {
     public abstract partial class BaseCommandEmitter : ICommandEmitter
     {
+        public int Columns { get; set; } = 42;
+
         /* Character Commands */
         public virtual byte[] SetStyles(PrintStyle style) => new byte[] { Cmd.ESC, Chars.StyleMode, (byte)style };
 
@@ -24,5 +27,58 @@ public abstract partial class BaseCommandEmitter : ICommandEmitter
         public virtual byte[] CodePage(CodePage codePage) => new byte[] { Cmd.ESC, Chars.CodePage, (byte)codePage };
 
         public virtual byte[] Color(Color color) => new byte[] { Cmd.ESC, Chars.Color, (byte)color };
+
+        public virtual byte[] HorizontalLine() => Print("".PadLeft(Columns, '-'));
+
+        public virtual byte[] HorizontalLine(char c) => Print("".PadLeft(Columns, c));
+
+        /// <summary>
+        /// Based on printer's column count provides a byte array for 1 full line where both texts fit, first one aligned to the left and the other to the right.
+        /// If total length of both texts is greater than printer's column count, Left Aligned text will get truncated to fit both and a whitespace will be added in between
+        /// </summary>
+        /// <param name="leftAlignedText">Text that will be aligned to the Left</param>
+        /// <param name="rightAlignedText">Text that will be aligned to the Right</param>
+        /// <returns>Byte array that contains a full line with one text aligned to the left and the other to the right.</returns>
+        /// <exception cref="ArgumentException"><paramref name="rightAlignedText"/> length is greater than column count.</exception>
+        /// <exception cref="ArgumentNullException"><paramref name="leftAlignedText"/> or <paramref name="rightAlignedText"/> is null.</exception>
+        public virtual byte[] SameLineLeftAndRightAlign(string leftAlignedText, string rightAlignedText)
+        {
+            if (leftAlignedText is null)
+            {
+                throw new ArgumentNullException(nameof(leftAlignedText));
+            }
+
+            if (rightAlignedText is null)
+            {
+                throw new ArgumentNullException(nameof(rightAlignedText));
+            }
+
+            int totalLength = leftAlignedText.Length + rightAlignedText.Length;
+            if (rightAlignedText.Length > Columns)
+            {
+                throw new ArgumentException($"Length of Right-Aligned text ({rightAlignedText.Length}) surpass the printer's column count ({Columns}).");
+            }
+
+            if (rightAlignedText.Length >= Columns - 1)
+            {
+                if (rightAlignedText.Length < Columns)
+                {
+                    rightAlignedText = $" {rightAlignedText}";
+                }
+                return Print(rightAlignedText);
+            }
+
+            string result;
+            if (totalLength >= Columns)
+            {
+                result = $"{leftAlignedText.Substring(0, Columns - (rightAlignedText.Length + 1))} {rightAlignedText}";
+            }
+            else
+            {
+                int padCount = Columns - totalLength;
+                result = $"{leftAlignedText}{rightAlignedText.PadLeft(padCount + rightAlignedText.Length, ' ')}";
+            }
+            return Print(result);
+        }
     }
 }

ESCPOS_NET/Emitters/ICommandEmitter.cs

@@ -6,6 +6,7 @@ namespace ESCPOS_NET.Emitters
     public interface ICommandEmitter
     {
         Encoding Encoding { get; set; }
+        int Columns { get; set; }
 
         /* Print Commands */
         byte[] PrintLine(string line = null);

README.md

@@ -71,7 +71,7 @@ printer.StartMonitoring();
 
 ## Step 2: Write a receipt to the printer
 ```csharp
-var e = new EPSON();
+var e = new EPSON{ Columns = 64 };
 printer.Write( // or, if using and immediate printer, use await printer.WriteAsync
   ByteSplicer.Combine(
     e.CenterAlign(),
@@ -97,13 +97,11 @@ printer.Write( // or, if using and immediate printer, use await printer.WriteAsy
     e.SetStyles(PrintStyle.FontB),
     e.PrintLine("1   TRITON LOW-NOISE IN-LINE MICROPHONE PREAMP"),
     e.PrintLine("    TRFETHEAD/FETHEAD                        89.95         89.95"),
-    e.PrintLine("----------------------------------------------------------------"),
-    e.RightAlign(),
-    e.PrintLine("SUBTOTAL         89.95"),
-    e.PrintLine("Total Order:         89.95"),
-    e.PrintLine("Total Payment:         89.95"),
+    e.HorizontalLine(),
+    e.SameLineLeftAndRightAlign("SUBTOTAL", "89.95"),
+    e.SameLineLeftAndRightAlign("Total Order:", "89.95"),
+    e.SameLineLeftAndRightAlign("Total Payment:", "89.95"),
     e.PrintLine(),
-    e.LeftAlign(),
     e.SetStyles(PrintStyle.Bold | PrintStyle.FontB),
     e.PrintLine("SOLD TO:                        SHIP TO:"),
     e.SetStyles(PrintStyle.FontB),