TextFormatter port issues

[Gillibald]

The TextFormatter port aka Avalonia 11.0 support can be tested via: https://github.com/AvaloniaUI/AvaloniaEdit/tree/dev

Post your issues here if you find any. Our fork now follows more closely the original project's source.

[Gillibald]

@danipen

• Long lines support is broken again. Editing/selection/going home-end in very long line is super slow. You can find a test file

[Gillibald]

• Slow performance scrolling a file on macOS

[danipen]

• We're leaking thousands of ForegroundTextTransformations when scrolling a document.
  

[Gillibald]

Are we leaking TextLines as well?

[danipen]

No. It seems we're only leaking ForegroundTextTransformation objects in some kind of cycle.

[HendrikMennen]

Just tried this, most things work.
One thing I noticed is folding is broken:

 Specified argument was out of the range of valid values.
System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
   at Avalonia.Media.TextFormatting.Unicode.Codepoint.ReadAt(ReadOnlySlice`1 text, Int32 index, Int32& count) in /_/src/Avalonia.Base/Media/TextFormatting/Unicode/Codepoint.cs:line 170
   at Avalonia.Media.TextFormatting.Unicode.LineBreakEnumerator.NextCharClass() in /_/src/Avalonia.Base/Media/TextFormatting/Unicode/LineBreakEnumerator.cs:line 295
   at Avalonia.Media.TextFormatting.Unicode.LineBreakEnumerator.MoveNext() in /_/src/Avalonia.Base/Media/TextFormatting/Unicode/LineBreakEnumerator.cs:line 57
   at Avalonia.Media.TextFormatting.TextFormatterImpl.TryGetLineBreak(TextRun textRun, LineBreak& lineBreak) in /_/src/Avalonia.Base/Media/TextFormatting/TextFormatterImpl.cs:line 454
   at Avalonia.Media.TextFormatting.TextFormatterImpl.FetchTextRuns(ITextSource textSource, Int32 firstTextSourceIndex, TextEndOfLine& endOfLine, Int32& textSourceLength) in /_/src/Avalonia.Base/Media/TextFormatting/TextFormatterImpl.cs:line 407
   at Avalonia.Media.TextFormatting.TextFormatterImpl.FormatLine(ITextSource textSource, Int32 firstTextSourceIndex, Double paragraphWidth, TextParagraphProperties paragraphProperties, TextLineBreak previousLineBreak) in /_/src/Avalonia.Base/Media/TextFormatting/T
extFormatterImpl.cs:line 62
   at AvaloniaEdit.Rendering.TextView.BuildVisualLine(DocumentLine documentLine, TextRunProperties globalTextRunProperties, VisualLineTextParagraphProperties paragraphProperties, VisualLineElementGenerator[] elementGeneratorsArray, IVisualLineTransformer[] lineTra
nsformersArray, Size availableSize) in C:\Users\hmenn\source\repos\VHDP\AvaloniaEdit\src\AvaloniaEdit\Rendering\TextView.cs:line 1122
   at AvaloniaEdit.Rendering.TextView.CreateAndMeasureVisualLines(Size availableSize) in C:\Users\hmenn\source\repos\VHDP\AvaloniaEdit\src\AvaloniaEdit\Rendering\TextView.cs:line 1011
   at AvaloniaEdit.Rendering.TextView.MeasureOverride(Size availableSize) in C:\Users\hmenn\source\repos\VHDP\AvaloniaEdit\src\AvaloniaEdit\Rendering\TextView.cs:line 941
   at Avalonia.Layout.Layoutable.MeasureCore(Size availableSize) in /_/src/Avalonia.Base/Layout/Layoutable.cs:line 520
   at Avalonia.Layout.Layoutable.Measure(Size availableSize) in /_/src/Avalonia.Base/Layout/Layoutable.cs:line 385
   at Avalonia.Layout.LayoutManager.Measure(ILayoutable control) in /_/src/Avalonia.Base/Layout/LayoutManager.cs:line 274
   at Avalonia.Layout.LayoutManager.ExecuteMeasurePass() in /_/src/Avalonia.Base/Layout/LayoutManager.cs:line 250
   at Avalonia.Layout.LayoutManager.InnerLayoutPass() in /_/src/Avalonia.Base/Layout/LayoutManager.cs:line 232
   at Avalonia.Layout.LayoutManager.ExecuteLayoutPass() in /_/src/Avalonia.Base/Layout/LayoutManager.cs:line 145
   at Avalonia.Threading.JobRunner.RunJobs(Nullable`1 priority) in /_/src/Avalonia.Base/Threading/JobRunner.cs:line 38
   at Avalonia.Win32.Win32Platform.WndProc(IntPtr hWnd, UInt32 msg, IntPtr wParam, IntPtr lParam) in /_/src/Windows/Avalonia.Win32/Win32Platform.cs:line 287
   at Avalonia.Win32.Interop.UnmanagedMethods.DispatchMessage(MSG& lpmsg)
   at Avalonia.Win32.Win32Platform.RunLoop(CancellationToken cancellationToken) in /_/src/Windows/Avalonia.Win32/Win32Platform.cs:line 214
   at Avalonia.Threading.Dispatcher.MainLoop(CancellationToken cancellationToken) in /_/src/Avalonia.Base/Threading/Dispatcher.cs:line 61
   at Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime.Start(String[] args) in /_/src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs:line 120
   at Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime[T](T builder, String[] args, ShutdownMode shutdownMode) in /_/src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs:line 209
   at VHDPlus.Program.Main(String[] args) in C:\Users\hmenn\source\repos\VHDP\VHDPlus\Program.cs:line 95

[Gillibald]

Could you provide the actual text you tried to display?

[HendrikMennen]

The text is not relevant here I guess.
It's simply the folding feature that does not work yet:

[Gillibald]

As long it is simply reproducible for me this should be simple to fix

[danipen]

BTW @Gillibald this one is fixed with Avalonia 11:

Slow performance scrolling a file on macOS

So feel free to mark it as completed (checked).

[HendrikMennen]

@Gillibald Is there a setting to prevent this from happening? For Code I prefer <=

[Gillibald]

Currently not out of the box. There are plans to introduce an API that allows to enable / disable certain font features like liga etc.

If you don't want ligatures at all you need to register a custom text shaper that disables this feature or use a font that does not have this ligature.

[HendrikMennen]

Thank you I just changed to a different font.
One more thing I noticed is the flickering in this version.
Seems like before providing a new frame, the old frame is cleared first.
Here a gif a 0.5x speed:

[danipen]

Yes. That flickering is new in Avalonia 11.

Probably related (or same issue) to this: AvaloniaUI/Avalonia#8830

[danipen]

The IBeam mouse pointer is lost when hovering text:

[danipen]

Unfortunately the following PR doesn't fix the flickering issue while selecting text: AvaloniaUI/Avalonia#8918

@Gillibald any idea of what's going on there? This didn't happen on the stable 0.10.x

[Gillibald]

Will have a look next week. Probably some issue with the way VisualLine is being rendered.

[Gillibald]

@HendrikMennen I can't repro the folding issue with AvaloniaEdit.Demo I need a repro to fix your issue

[Gillibald]

@danipen #252

[HendrikMennen]

Its quite weird: For testing I used this folding strategy: https://github.com/icsharpcode/AvalonEdit/blob/master/ICSharpCode.AvalonEdit.Sample/BraceFoldingStrategy.cs

This works:

These examples crash:

I guess you used the builtin XmlFoldingStrategy to reproduce?
In that case use this xml code:

<Project Sdk="Microsoft.NET.Sdk">

  CRASH here ! <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
    <WarningsNotAsErrors>0612,0618</WarningsNotAsErrors>
	<PackageId>Avalonia.AvaloniaEdit</PackageId>
  </PropertyGroup>

</Project>

[Gillibald]

Y I was using the XmlFoldingStrategy. Let me try your implementation.