Improved Clipboard on Linux

samples/Myra.Samples.NonModalWindows/UI/MainPanel.cs

@@ -1,5 +1,6 @@
 /* Generated by MyraPad at 04.12.2019 21:54:46 */
 using Microsoft.Xna.Framework;
+using Myra.Graphics2D.UI;
 
 namespace Myra.Samples.NonModalWindows.UI
 {

src/Myra/TextCopy/Clipboard.cs

@@ -51,7 +51,10 @@ static Action<string> CreateSet()
 
             if (CurrentPlatform.OS == OS.Linux)
             {
-                return LinuxClipboard.SetText;
+                if(LinuxClipboard.SystemIsCompatible())
+                    return LinuxClipboard.SetText;
+                Console.WriteLine(LinuxClipboard.GetCompatibilityProblem());
+                UseLocalClipboard = true;
             }
 
             return s => throw new NotSupportedException();
@@ -71,7 +74,10 @@ static Func<string> CreateGet()
 
             if (CurrentPlatform.OS == OS.Linux)
             {
-                return LinuxClipboard.GetText;
+                if(LinuxClipboard.SystemIsCompatible())
+                    return LinuxClipboard.GetText;
+                Console.WriteLine(LinuxClipboard.GetCompatibilityProblem());
+                UseLocalClipboard = true;
             }
 
             return () => throw new NotSupportedException();

src/Myra/TextCopy/LinuxClipboard.cs

@@ -1,27 +1,98 @@
+using System;
 using System.IO;
 
 static class LinuxClipboard
 {
+    private enum ClipCmd
+    {
+        Incompatible,
+        XClip,
+        XSel, 
+    }
+    private static ClipCmd Cmd = ClipCmd.Incompatible;
+
+    public static string GetCompatibilityProblem()
+    {
+        return @"Myra: At least one package needs to be installed on the system: 'xclip', 'xsel'. Clipboard function will be limited.";
+    }
+
+    /// <summary>
+    /// Return true if 'xclip' or 'xsel' is installed on the system.
+    /// </summary>
+    public static bool SystemIsCompatible()
+    {
+        ClipCmd clipCmd = ClipCmd.Incompatible;
+
+        if(TestBashCommandExists("xsel --version")) //dash differences are intentional
+        {
+            clipCmd = ClipCmd.XSel;
+        }
+        else if (TestBashCommandExists("xclip -version"))
+        {
+            clipCmd = ClipCmd.XClip;
+        }
+
+        Cmd = clipCmd;
+        return Cmd != ClipCmd.Incompatible;
+    }
+    private static bool TestBashCommandExists(string cmd)
+    {
+        string bashMsg;
+        try
+        {
+            bashMsg = BashRunner.Run(cmd);
+        }
+        catch (Exception e)
+        {
+            bashMsg = e.Message;
+        }
+        return !bashMsg.Contains("Could not execute process.");
+    }
+
     public static void SetText(string text)
     {
         var tempFileName = Path.GetTempFileName();
         File.WriteAllText(tempFileName, text);
         try
         {
-            BashRunner.Run($"cat {tempFileName} | xclip");
+            switch (Cmd)
+            {
+                case ClipCmd.XClip:
+                    BashRunner.Run($"cat {tempFileName} | xclip -sel clip");
+                    break;
+                case ClipCmd.XSel:
+                    BashRunner.Run($"cat {tempFileName} | xsel -ib");
+                    break;
+                case ClipCmd.Incompatible:
+                    throw new SystemException(GetCompatibilityProblem());
+                default:
+                    throw new NotImplementedException(Cmd.ToString());
+            }
         }
         finally
         {
             File.Delete(tempFileName);
         }
     }
-
+    
     public static string GetText()
     {
         var tempFileName = Path.GetTempFileName();
         try
         {
-            BashRunner.Run($"xclip -o > {tempFileName}");
+            switch (Cmd)
+            {
+                case ClipCmd.XClip:
+                    BashRunner.Run($"xclip -o -sel clip > {tempFileName}");
+                    break;
+                case ClipCmd.XSel:
+                    BashRunner.Run($"xsel -ob > {tempFileName}");
+                    break;
+                case ClipCmd.Incompatible:
+                    throw new SystemException(GetCompatibilityProblem());
+                default:
+                    throw new NotImplementedException(Cmd.ToString());
+            }
             return File.ReadAllText(tempFileName);
         }
         finally