RichTextKit/SkiaSharp on Android: Could not resolve type with token 0100000b from typeref (expected class 'System.ReadOnlySpan`1' in assembly 'mscorlib')

[mikegoatly]

Description

When running a MAUI project on Android using RichTextKit to render text on a SkiaSharp SKCanvasView control the following exception is thrown:

System.TypeLoadException
  Message=Could not resolve type with token 0100000b from typeref (expected class 'System.ReadOnlySpan`1' in assembly 'mscorlib, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e')

Repo here: https://github.com/mikegoatly/MauiExperiments/tree/main/MauiRichTextKit

I'm guessing that code is being trimmed that's needed?

Steps to Reproduce

1. Create a new MAUI project
2. Add a package reference to SkiaSharp.Views.Maui.Controls
3. Add .UseSkiaSharp() to MauiProgram
4. Change MainPage.xaml to have this as content:

<Grid>
    <sk:SKCanvasView PaintSurface="SKCanvasView_PaintSurface"/>
</Grid>

5. Add this to MainPage.xaml.cs:

private void SKCanvasView_PaintSurface(object sender, SkiaSharp.Views.Maui.SKPaintSurfaceEventArgs e)
{
  var text = new TextBlock();
  var styleManager = StyleManager.Default.Value;
  styleManager.FontSize(40);
  styleManager.HaloColor(SKColors.Red);
  styleManager.HaloWidth(4);
  styleManager.HaloBlur(2);
  
  text.AddText("Hello MAUI!", styleManager.CurrentStyle);
  
  text.Paint(e.Surface.Canvas, new SKPoint(100, 200));
}

Debug the app on Android (I'm using Pixel 5 - API 30 (Android 11.0 - API 30)) and get the error. Note that the app works fine when running as a Windows app.

Version with bug

Preview 13 (current)

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

Android 11 and up

Did you find any workaround?

No response

Relevant log output

No response

[Amir-Care]

Verified repro with Version 17.2.0 Preview 2.0 [32208.484.main] on Android and can works fine on Windwos.

• Throw exception:

  

Sample project: #5142.zip

[mattleibow]

I am wondering if you are using too old a SkiaSharp and RichTextKit? The latest version of vs brings maui p14 which is onky compatible with skia preview 232

[mikegoatly]

@mattleibow I've just updated the repo project to use SkiaSharp.Views.Maui.Controls 2.88.0-preview.232 and still get the same error.

The sample code is already running on the latest available version of RichTextKit, and the callstack at the point of error is:

0x2B in Topten.RichTextKit.TextBlock.CreateFontRun at C:\Users\Brad\Projects\RichTextKit\Topten.RichTextKit\TextBlock.cs:1305,17
0x65 in Topten.RichTextKit.TextBlock.FlushUnshapedRuns at C:\Users\Brad\Projects\RichTextKit\Topten.RichTextKit\TextBlock.cs:1236,17
0x367 in Topten.RichTextKit.TextBlock.BuildFontRuns at C:\Users\Brad\Projects\RichTextKit\Topten.RichTextKit\TextBlock.cs:1129,17
0xF6 in Topten.RichTextKit.TextBlock.Layout at C:\Users\Brad\Projects\RichTextKit\Topten.RichTextKit\TextBlock.cs:313,17
0xB in Topten.RichTextKit.TextBlock.Paint at C:\Users\Brad\Projects\RichTextKit\Topten.RichTextKit\TextBlock.cs:359,13
0x1E in Topten.RichTextKit.TextBlock.Paint at C:\Users\Brad\Projects\RichTextKit\Topten.RichTextKit\TextBlock.cs:419,13
0x76 in MauiRichTextKit.MainPage.SKCanvasView_PaintSurface at C:\Users\mikeg\source\repos\MauiExperiments\MauiRichTextKit\MauiRichTextKit\MainPage.xaml.cs:25,2
0xD in SkiaSharp.Views.Maui.Controls.SKCanvasView.OnPaintSurface at D:\a\1\s\source\SkiaSharp.Views.Forms\SkiaSharp.Views.Forms.Shared\SKCanvasView.cs:74,4
0x2 in SkiaSharp.Views.Maui.Controls.SKCanvasView.SkiaSharp.Views.Maui.ISKCanvasView.OnPaintSurface at D:\a\1\s\source\SkiaSharp.Views.Maui\SkiaSharp.Views.Maui.Controls\SKCanvasView.HandlerImpl.cs:33,4
0x52 in SkiaSharp.Views.Maui.Handlers.SKCanvasViewHandler.OnPaintSurface at D:\a\1\s\source\SkiaSharp.Views.Maui\SkiaSharp.Views.Maui.Core\Handlers\SKCanvasView\SKCanvasViewHandler.Android.cs:68,4
0xD in SkiaSharp.Views.Android.SKCanvasView.OnPaintSurface at D:\a\1\s\source\SkiaSharp.Views\SkiaSharp.Views.Android\SKCanvasView.cs:134,4
0xB6 in SkiaSharp.Views.Android.SKCanvasView.OnDraw at D:\a\1\s\source\SkiaSharp.Views\SkiaSharp.Views.Android\SKCanvasView.cs:113,4
0x11 in Android.Views.View.n_OnDraw_Landroid_graphics_Canvas_ at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net6.0/android-32/mcw/Android.Views.View.cs:18211,4
0x9 in Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PPL_V at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:110,5

Which is this line:

shaped = shaper.Shape(_textShapingBuffers, codePoints, style, direction, codePoints.Start, asFallbackFor, ResolveTextAlignment());

However because the error is a type resolution error, I don't think that line is actually to blame. Looking at what's going on in the TextShaper.Shape method that's being called, this is the first time I think the HarfBuzzSharp library will be invoked, so it's very possible that there's something being trimmed in that that's actually the problem here?