TextArea.ScrollToStart/End fixes

src/Eto.Gtk/Forms/Controls/TextAreaHandler.cs

@@ -371,20 +371,32 @@ public virtual void ScrollTo(Range<int> range)
 			Control.ScrollToMark(mark, 0, false, 0, 0);
 		}
 
+		double GetScrollX() => Control.Direction switch
+		{
+			Gtk.TextDirection.Rtl => Control.Justification switch
+			{
+				Gtk.Justification.Right => scroll.Hadjustment.Lower,
+				Gtk.Justification.Center => (scroll.Hadjustment.Upper - scroll.Hadjustment.Lower - scroll.Hadjustment.PageSize) / 2,
+				_ => scroll.Hadjustment.Upper,
+			},
+			_ => Control.Justification switch
+			{
+				Gtk.Justification.Right => scroll.Hadjustment.Upper,
+				Gtk.Justification.Center => (scroll.Hadjustment.Upper - scroll.Hadjustment.Lower - scroll.Hadjustment.PageSize) / 2,
+				_ => scroll.Hadjustment.Lower,
+			},
+		};
+
 		public virtual void ScrollToEnd()
 		{
-			var end = Control.Buffer.EndIter;
-			var mark = Control.Buffer.CreateMark(null, end, false);
-			Control.ScrollToMark(mark, 0, false, 0, 0);
+			scroll.Vadjustment.Value = scroll.Vadjustment.Upper - scroll.Vadjustment.PageSize;
+			scroll.Hadjustment.Value = GetScrollX();
 		}
 
 		public virtual void ScrollToStart()
 		{
-			var end = Control.Buffer.StartIter;
-			var mark = Control.Buffer.CreateMark(null, end, false);
-			Control.ScrollToMark(mark, 0, false, 0, 0);
-		}
-
-
+			scroll.Vadjustment.Value = scroll.Vadjustment.Lower;
+			scroll.Hadjustment.Value = GetScrollX();
+		}		
 	}
 }

src/Eto.Mac/Forms/Controls/TextAreaHandler.cs

@@ -452,11 +452,40 @@ public BorderType Border
 		}
 
 		public int TextLength => (int)Control.TextStorage.Length;
-
-		public void ScrollTo(Range<int> range) => Control.ScrollRangeToVisible(range.ToNS());
 
-		public void ScrollToStart() => ScrollTo(new Range<int>(0));
+		public void ScrollTo(Range<int> range)
+		{
+			var nsRange = range.ToNS();
+			Control.LayoutManager.EnsureLayoutForCharacterRange(nsRange);
+			Control.ScrollRangeToVisible(nsRange);
+		}
+
+		public void ScrollToStart()
+		{ 
+			Control.LayoutManager.EnsureLayoutForCharacterRange(new NSRange(0, Control.TextStorage.Length));
+			Control.ScrollRectToVisible(new CGRect(GetScrollX(), 0, 1, 1));
+		}
+
+		nfloat GetScrollX() => Control.UserInterfaceLayoutDirection switch
+		{
+			NSUserInterfaceLayoutDirection.RightToLeft => Control.Alignment switch
+			{
+				NSTextAlignment.Right => Control.Bounds.Left,
+				NSTextAlignment.Center => Control.Bounds.GetMidX() - Scroll.DocumentVisibleRect.Width / 2,
+				_ => Control.Bounds.Right,
+			},
+			_ => Control.Alignment switch
+			{
+				NSTextAlignment.Right => Control.Bounds.Right,
+				NSTextAlignment.Center => Control.Bounds.GetMidX() - Scroll.DocumentVisibleRect.Width / 2,
+				_ => Control.Bounds.Left,
+			},
+		};
 
-		public void ScrollToEnd() => ScrollTo(Range.FromLength(TextLength, 0));
+		public void ScrollToEnd()
+		{
+			Control.LayoutManager.EnsureLayoutForCharacterRange(new NSRange(0, Control.TextStorage.Length));
+			Control.ScrollPoint(new CGPoint(GetScrollX(), Control.Bounds.Bottom));
+		}
 	}
 }

src/Eto.WinForms/Forms/Controls/TextAreaHandler.cs

@@ -213,12 +213,15 @@ public override bool ShouldBubbleEvent(swf.Message msg)
 			return !intrinsicEvents.Contains((Win32.WM)msg.Msg) && base.ShouldBubbleEvent(msg);
 		}
 
+		TextAlignment _textAlignment;
+
 		public TextAlignment TextAlignment
 		{
-			get { return Control.SelectionAlignment.ToEto(); }
+			get => _textAlignment;
 			set
 			{
 				if (value == TextAlignment) return;
+				_textAlignment = value;
 				var sel = Selection;
 				Control.SelectAll();
 				Control.SelectionAlignment = value.ToSWF();
@@ -277,18 +280,23 @@ public void ScrollTo(Range<int> range)
 			Win32.SendMessage(Control.Handle, Win32.WM.EM_SETSCROLLPOS, IntPtr.Zero, ref scrollPosition);
 		}
 
+		Win32.SB GetScrollX() => Control.RightToLeft switch
+		{
+			swf.RightToLeft.Yes => Win32.SB.RIGHT,
+			_ => Win32.SB.LEFT
+		};
+
 		public void ScrollToStart()
 		{
 			Win32.SendMessage(Control.Handle, Win32.WM.VSCROLL, (IntPtr)Win32.SB.TOP, IntPtr.Zero);
-			Win32.SendMessage(Control.Handle, Win32.WM.HSCROLL, (IntPtr)Win32.SB.LEFT, IntPtr.Zero);
+			Win32.SendMessage(Control.Handle, Win32.WM.HSCROLL, (IntPtr)GetScrollX(), IntPtr.Zero);
 		}
 
 		public void ScrollToEnd()
 		{
 			Win32.SendMessage(Control.Handle, Win32.WM.VSCROLL, (IntPtr)Win32.SB.BOTTOM, IntPtr.Zero);
-			Win32.SendMessage(Control.Handle, Win32.WM.HSCROLL, (IntPtr)Win32.SB.LEFT, IntPtr.Zero);
+			Win32.SendMessage(Control.Handle, Win32.WM.HSCROLL, (IntPtr)GetScrollX(), IntPtr.Zero);
 		}
 
-
 	}
 }

src/Eto.Wpf/Forms/Controls/TextAreaHandler.cs

@@ -258,9 +258,33 @@ public virtual BorderType Border
 
 		public abstract void ScrollTo(Range<int> range);
 
-		public virtual void ScrollToEnd() => Control.ScrollToEnd();
+		double GetScrollX() => Control.FlowDirection switch
+		{
+			sw.FlowDirection.RightToLeft => Control.HorizontalContentAlignment switch
+			{
+				sw.HorizontalAlignment.Right => 0,
+				sw.HorizontalAlignment.Center => (Control.ExtentWidth - Control.ViewportWidth) / 2,
+				_ => Control.ExtentWidth,
+			},
+			_ => Control.HorizontalContentAlignment switch
+			{
+				sw.HorizontalAlignment.Right => Control.ExtentWidth,
+				sw.HorizontalAlignment.Center => (Control.ExtentWidth - Control.ViewportWidth) / 2,
+				_ => 0,
+			},
+		};
+
+		public virtual void ScrollToEnd()
+		{
+			Control.ScrollToVerticalOffset(Control.ExtentHeight);
+			Control.ScrollToHorizontalOffset(GetScrollX());
+		}
 
-		public virtual void ScrollToStart() => Control.ScrollToHome();
+		public virtual void ScrollToStart()
+		{
+			Control.ScrollToVerticalOffset(0);
+			Control.ScrollToHorizontalOffset(GetScrollX());
+		}
 
 		public abstract int TextLength { get; }
 

src/Eto/Forms/Controls/TextArea.cs

@@ -320,12 +320,12 @@ public void Append(string text, bool scrollToCursor = false)
 	public void ScrollTo(Range<int> range) => Handler.ScrollTo(range);
 
 	/// <summary>
-	/// Scrolls to the start of the text in the text area.
+	/// Scrolls to the start of the text aligned on the same horizontal side as <see cref="TextAlignment"/>.
 	/// </summary>
 	public void ScrollToStart() => Handler.ScrollToStart();
 
 	/// <summary>
-	/// Scrolls to the end of the text in the text area.
+	/// Scrolls to the end of the text aligned on the same horizontal side as <see cref="TextAlignment"/>.
 	/// </summary>
 	public void ScrollToEnd() => Handler.ScrollToEnd();
 

test/Eto.Test/Handlers/TabControlHandler.cs

@@ -30,7 +30,7 @@ public TabControlHandler()
 				},
 			};
 
-			ContentPanel = new Panel { BackgroundColor = Colors.White };
+			ContentPanel = new Panel { BackgroundColor = SystemColors.ControlBackground };
 			var layout = new DynamicLayout { Padding = Padding.Empty, Spacing = Size.Empty };
 			layout.BeginHorizontal();
 			layout.Add(tabs);

test/Eto.Test/LoremGenerator.cs

@@ -0,0 +1,53 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Eto.Test
+{
+    public static class LoremGenerator
+    {
+        private static readonly string[] Words = new[]
+        {
+            "lorem", "ipsum", "dolor", "sit", "amet", "consectetur", "adipiscing", "elit", "sed", "do",
+            "eiusmod", "tempor", "incididunt", "ut", "labore", "et", "dolore", "magna", "aliqua", "ut",
+            "enim", "ad", "minim", "veniam", "quis", "nostrud", "exercitation", "ullamco", "laboris",
+            "nisi", "ut", "aliquip", "ex", "ea", "commodo", "consequat", "duis", "aute", "irure", "dolor",
+            "in", "reprehenderit", "in", "voluptate", "velit", "esse", "cillum", "dolore", "eu", "fugiat",
+            "nulla", "pariatur", "excepteur", "sint", "occaecat", "cupidatat", "non", "proident", "sunt",
+            "in", "culpa", "qui", "officia", "deserunt", "mollit", "anim", "id", "est", "laborum"
+        };
+
+        public static string Generate(int wordCount, bool randomize = true)
+        {
+            var random = new Random();
+            var result = new List<string>();
+
+            for (int i = 0; i < wordCount; i++)
+            {
+                var word = Words[randomize ? random.Next(Words.Length) : i % Words.Length];
+                result.Add(word);
+            }
+
+            return string.Join(" ", result);
+        }
+
+        public static string GenerateLines(int lineCount, int maxWordsPerLine, bool randomize = true)
+		{
+			return GenerateLines(lineCount, 0, maxWordsPerLine, randomize);
+		}
+        public static string GenerateLines(int lineCount, int minWordsPerLine, int maxWordsPerLine, bool randomize = true)
+        {
+            var random = new Random();
+            var result = new List<string>();
+
+            for (int i = 0; i < lineCount; i++)
+            {
+                var line = Generate(random.Next(minWordsPerLine, maxWordsPerLine), randomize);
+                result.Add(line);
+            }
+
+            return string.Join("\n", result);
+        }
+    }
+}

test/Eto.Test/Sections/Controls/LabelSection.cs

@@ -62,7 +62,7 @@ Control MiddleLabel()
 				Text = "Middle Center Align",
 				TextAlignment = TextAlignment.Center,
 				VerticalAlignment = VerticalAlignment.Center,
-				BackgroundColor = Colors.AliceBlue
+				BackgroundColor = Colors.Gray
 			};
 		}
 
@@ -73,7 +73,7 @@ Control BottomLabel()
 				Text = "Bottom Center Align",
 				TextAlignment = TextAlignment.Center,
 				VerticalAlignment = VerticalAlignment.Bottom,
-				BackgroundColor = Colors.AliceBlue
+				BackgroundColor = Colors.Gray
 			};
 		}
 
@@ -125,7 +125,7 @@ Control WrapLabel()
 		{
 			var label = new Label
 			{
-				Text = Utility.LoremTextWithTwoParagraphs
+				Text = LoremGenerator.GenerateLines(2, 50, 100)
 			};
 
 			var wrapDropDown = new EnumDropDown<WrapMode>();

test/Eto.Test/Sections/Controls/RichTextAreaSection.cs

@@ -5,7 +5,7 @@ public class RichTextAreaSection : Panel
 	{
 		public static string RtfString = "{\\rtf1\\ansi\\ansicpg1252\\cocoartf1343\\cocoasubrtf160\r\n{\\fonttbl\\f0\\fswiss\\fcharset0 Helvetica;}\r\n{\\colortbl;\\red255\\green255\\blue255;}\r\n\\margl1440\\margr1440\\vieww10800\\viewh8400\\viewkind0\r\n\\pard\\tx566\\tx1133\\tx1700\\tx2267\\tx2834\\tx3401\\tx3968\\tx4535\\tx5102\\tx5669\\tx6236\\tx6803\\pardirnatural\r\n\r\n\\f0\\fs24 \\cf0 This is some \r\n\\b bold\r\n\\b0 , \r\n\\i italic\r\n\\i0 , and \\ul underline\\ulnone  text! \\\r\n\\\r\n\\pard\\tx566\\tx1133\\tx1700\\tx2267\\tx2834\\tx3401\\tx3968\\tx4535\\tx5102\\tx5669\\tx6236\\tx6803\\pardirnatural\\qr\r\n\\cf0 Some other text}";
 
-		static string LastText = Utility.LoremTextWithTwoParagraphs;
+		static string LastText = LoremGenerator.GenerateLines(4, 50);
 
 		public RichTextAreaSection()
 		{

test/Eto.Test/Sections/Controls/TextAreaSection.cs

@@ -10,7 +10,7 @@ public TextAreaSection()
 
 		Control Default()
 		{
-			var text = new TextArea { Text = Utility.LoremTextWithTwoParagraphs };
+			var text = new TextArea { Text = LoremGenerator.GenerateLines(3, 100) };
 			LogEvents(text);
 
 			return new TableLayout

test/Eto.Test/Sections/Drawing/FormattedTextSection.cs

@@ -23,7 +23,7 @@ public FormattedTextSection()
 
 			var formattedText = new FormattedText
 			{
-				Text = Utility.LoremTextWithTwoParagraphs,
+				Text = LoremGenerator.GenerateLines(2, 10, 30),
 				MaximumSize = new SizeF(500, 80),
 				Wrap = FormattedTextWrapMode.Word,
 				Trimming = FormattedTextTrimming.CharacterEllipsis,
@@ -34,7 +34,7 @@ public FormattedTextSection()
 
 			var formattedTextWithNewLines = new FormattedText
 			{
-				Text = Utility.LoremTextWithNewLines,
+				Text = LoremGenerator.GenerateLines(6, 10, 20),
 				Wrap = FormattedTextWrapMode.Word,
 				Trimming = FormattedTextTrimming.CharacterEllipsis,
 				ForegroundBrush = Brushes.White,

test/Eto.Test/UnitTests/Forms/Controls/LabelTests.cs

@@ -28,7 +28,7 @@ public void WrapModeNoneShouldAllowNewLines()
 			{
 				var label = new Label
 				{
-					Text = Utility.LoremTextWithTwoParagraphs,
+					Text = LoremGenerator.GenerateLines(2, 50),
 					Wrap = WrapMode.None
 				};
 				var layout = new PixelLayout

test/Eto.Test/UnitTests/Forms/Controls/TextAreaTests.cs

@@ -11,6 +11,28 @@ public class TextAreaTests : TextAreaTests<TextArea>
 	public class TextAreaTests<T> : TestBase
 		where T : TextArea, new()
 	{
+		[Test]
+		[ManualTest]
+		public void ScrollToEndShouldHaveValidStateAfterTextIsInserted() => ManualForm(
+			"TextArea should scroll to the end after each time text is inserted,\nand should be fully visible",
+			(form, label) =>
+		{
+			var textArea = new T { Size = new Size(400, 300) };
+
+			form.Shown += async (sender, e) =>
+			{
+				for (int i = 0; i < 20; i++)
+				{
+					textArea.Text += LoremGenerator.GenerateLines(10, 100);
+					textArea.ScrollToEnd();
+					await Task.Delay(200);
+				}
+			};
+
+			return textArea;
+		});
+
+
 		[Test]
 		public void CheckSelectionTextCaretAfterSettingText()
 		{

test/Eto.Test/UnitTests/Forms/MessageBoxTests.cs

@@ -7,14 +7,14 @@ public class MessageBoxTests : TestBase
 {
 	public static IEnumerable<string> GetMessages()
 	{
-		yield return Utility.GenerateLoremText(2);
-		yield return Utility.GenerateLoremText(10);
-		yield return Utility.GenerateLoremText(20);
-		yield return Utility.GenerateLoremText(100, true);
-		yield return Utility.GenerateLoremText(1000, true);
-		yield return Utility.GenerateLoremText(1000, false);
-		yield return Utility.GenerateLoremText(3000, true);
-		yield return Utility.GenerateLoremText(3000, false);
+		yield return LoremGenerator.Generate(2);
+		yield return LoremGenerator.Generate(10);
+		yield return LoremGenerator.Generate(20);
+		yield return LoremGenerator.GenerateLines(2, 100);
+		yield return LoremGenerator.GenerateLines(4, 1000);
+		yield return LoremGenerator.Generate(1000);
+		yield return LoremGenerator.GenerateLines(20, 300);
+		yield return LoremGenerator.Generate(3000);
 	}
 
 	[TestCaseSource(nameof(GetMessages))]