Experimental Support for CUPS Printing, not working as of now.

Tanshu.Accounts.PointOfSale/App.config

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <connectionStrings>
-    <add name="FluentCon" connectionString="Server=sovereign;Initial Catalog=Pets;User ID=sa;Password=123456" />
+    <add name="FluentCon" connectionString="Server=.;Initial Catalog=Pets;User ID=sa;Password=123456" />
   </connectionStrings>
   <appSettings>
     <add key ="Location" value ="Office"/>

Tanshu.Accounts.PointOfSale/Controllers/BillController.cs

@@ -456,13 +456,15 @@ namespace Tanshu.Accounts.PointOfSale
             _saleForm.ClearBill(_bill);
         }
 
-        public void FormLoad()
+        public SaleFormState FormLoad()
         {
             ClearBill();
             if (_editVoucherID.HasValue)
             {
                 LoadBill(_editVoucherID.Value);
+                return SaleFormState.Billing;
             }
+            return SaleFormState.Waiting;
         }
 
         internal void SettleBill()

Tanshu.Accounts.Print/PlatformPrinter.cs

@@ -0,0 +1,8 @@
+namespace Tanshu.Accounts.Print
+{
+    // Cut Code for the printer Alt-29, Alt-86, Alt-49
+    internal abstract class PlatformPrinter
+    {
+        internal abstract bool Print(string printerName, string documentName, string printingText);
+    }
+}

Tanshu.Accounts.Print/PrinterLinux.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Tanshu.Accounts.Print
+{
+    internal class PrinterLinux : PlatformPrinter
+    {
+        #region API Declarations
+        // ReSharper disable InconsistentNaming
+        [DllImport("libcups", CharSet = CharSet.Ansi)]
+        static extern int cupsPrintFile(string printer, string filename, string title, int num_options, IntPtr options);
+        // int cupsPrintFile (const char *name, const char *filename, const char *title, int num_options, cups_option_t *options);
+
+        [DllImport("libcups", CharSet = CharSet.Ansi)]
+        static extern int cupsCreateJob(string http, string name, string title, int num_options, IntPtr options);
+        // int cupsCreateJob (http_t *http, const char *name, const char *title, int num_options, cups_option_t *options);
+
+        [DllImport("libcups", CharSet = CharSet.Ansi)]
+        static extern int cupsStartDocument(string http, string name, int job_id, string docname, string format, int last_document);
+        // http_status_t cupsStartDocument (http_t *http, const char *name, int job_id, const char *docname, const char *format, int last_document);
+
+        [DllImport("libcups", CharSet = CharSet.Ansi)]
+        static extern int cupsWriteRequestData(string http, string buffer, int length);
+        // http_status_t cupsWriteRequestData (http_t *http, const char *buffer, size_t length);
+
+        [DllImport("libcups", CharSet = CharSet.Ansi)]
+        static extern int cupsFinishDocument(string http, string name);
+        // ipp_status_t cupsFinishDocument (http_t *http, const char *name);
+        // ReSharper restore InconsistentNaming
+        #endregion
+
+        internal override bool Print(string printerName, string documentName, string printingText)
+        {
+            var cupsOption = new IntPtr(0);
+            const string CUPS_HTTP_DEFAULT = "CUPS_HTTP_DEFAULT";
+            var jobId = cupsCreateJob(CUPS_HTTP_DEFAULT, printerName, documentName, 0, cupsOption);
+            if (jobId > 0)
+            {
+                const string format = "CUPS_FORMAT_TEXT";
+                cupsStartDocument(CUPS_HTTP_DEFAULT, printerName, jobId, documentName, format, 1);
+                cupsWriteRequestData(CUPS_HTTP_DEFAULT, printingText, printingText.Length);
+                cupsFinishDocument(CUPS_HTTP_DEFAULT, printerName);
+            }
+            return jobId > 0;
+        }
+    }
+}

Tanshu.Accounts.Print/PrinterWindows.cs

@@ -1,12 +1,9 @@
 using System;
-using System.IO;
 using System.Runtime.InteropServices;
-using System.Collections.Generic;
-using System.Text;
 
 namespace Tanshu.Accounts.Print
 {
-    internal class RawPrinterHelper
+    internal class PrinterWindows : PlatformPrinter
     {
         // Cut Code for the printer Alt-29, Alt-86, Alt-49
         #region API Declarations
@@ -43,35 +40,28 @@ namespace Tanshu.Accounts.Print
         internal static extern bool WritePrinter(IntPtr hPrinter, IntPtr pBytes, Int32 dwCount, out Int32 dwWritten);
         #endregion
 
-        internal static bool PrintString(string printerName, string documentName, string printingText, char[] lineBreakChars)
+        internal override bool Print(string printerName, string documentName, string printingText)
         {
-            string[] PageText;
             IntPtr hPrinter = new IntPtr(0);
             // The printer handle.
-            Int32 dwError;
             // Last error -incase there was trouble.
             DOCINFOA di = new DOCINFOA();
             // Describes your document(name, port, data type).
-            bool bSuccess = false; // Your success code.
+            var bSuccess = false; // Your success code.
 
             // Set up the DOCINFO structure. 
             di.pDocName = documentName;
             di.pDataType = "RAW";
-            PageText = printingText.Split(lineBreakChars );
 
-            if (OpenPrinter(printerName.Normalize(), out  hPrinter, System.IntPtr.Zero))
+            if (OpenPrinter(printerName.Normalize(), out hPrinter, IntPtr.Zero))
             {
                 if (StartDocPrinter(hPrinter, 1, di))
                 {
-                    for (int i = 0; i < PageText.Length; i++)
+                    if (!StartPagePrinter(hPrinter))
-                    {
+                        return false;
-                        if (StartPagePrinter(hPrinter))
-                        {
                     //Write your printer - specific bytes to the printer.
-                            bSuccess = SendLine(PageText[i], hPrinter);
+                    bSuccess = SendLine(printingText, hPrinter);
                     EndPagePrinter(hPrinter);
-                        }
-                    }
                     EndDocPrinter(hPrinter);
                 }
                 ClosePrinter(hPrinter);
@@ -79,14 +69,13 @@ namespace Tanshu.Accounts.Print
             // If you did not succeed, GetLastError may give more information about why not.
             if (bSuccess == false)
             {
-                dwError = Marshal.GetLastWin32Error();
+                Marshal.GetLastWin32Error();
             }
             return bSuccess;
         }// SendBytesToPrinter()
             
         internal static bool SendLine(string szString, IntPtr hPrinter)
         {
-            bool bSuccess = false;
             Int32 dwWritten = 0;
             Int32 dwCount = szString.Length; // How many characters are in the string?
 
@@ -95,9 +84,7 @@ namespace Tanshu.Accounts.Print
             // the string to ANSI text.
 
             // Write your bytes.
-            bSuccess = WritePrinter(hPrinter, pBytes, dwCount, out dwWritten);
+            return WritePrinter(hPrinter, pBytes, dwCount, out dwWritten);
-
-            return bSuccess;
         }
     }
 }

Tanshu.Accounts.Print/Tanshu.Accounts.Print.csproj

@@ -78,7 +78,10 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
-    <Compile Include="RawPrinterHelper.cs" />
+    <Compile Include="PlatformPrinter.cs" />
+    <Compile Include="PrinterLinux.cs" />
+    <Compile Include="ThermalPrinter.cs" />
+    <Compile Include="PrinterWindows.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Thermal.cs" />
   </ItemGroup>

Tanshu.Accounts.Print/Thermal.cs

@@ -239,19 +239,9 @@ namespace Tanshu.Accounts.Print
             MessageBox.Show(text);
             return true;
 #else
-            try
-            {
             text += printer.CutCode;
-                if (!RawPrinterHelper.PrintString(printer.Printer, documentName, text, new[] { ';' }))
+            if (!ThermalPrinter.Printer.Print(printer.Printer, documentName, text))
-                {
-                    GC.Collect();
                 MessageBox.Show("Error in PrintRAW Function. Please Report immediately");
-                }
-            }
-            catch (Exception ex)
-            {
-                throw ex;
-            }
             return true;
 #endif
         }

Tanshu.Accounts.Print/ThermalPrinter.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Tanshu.Accounts.Print
+{
+    internal class ThermalPrinter
+    {
+        private static readonly bool _runningOnLinux;
+        internal static PlatformPrinter Printer;
+        static ThermalPrinter()
+        {
+            _runningOnLinux = RunningOnLinux();
+            Printer = _runningOnLinux ? (PlatformPrinter)new PrinterLinux() : new PrinterWindows();
+        }
+
+        internal static bool RunningOnLinux()
+        {
+            var platform = (int)Environment.OSVersion.Platform;
+            if ((platform == 4) || (platform == 6) || (platform == 128))
+            {
+                if (Environment.GetEnvironmentVariable("not_supported_MONO_MWF_USE_NEW_X11_BACKEND") != null ||
+                    Environment.GetEnvironmentVariable("MONO_MWF_MAC_FORCE_X11") != null)
+                {
+                    return true;
+                }
+            }
+            return false;
+        }
+    }
+}