TextureToSkImage problem

antokhio · October 1, 2025, 8:30am

Hello, having a weirdo problem with TextureToSkImage, I suspect due to bug in caching:

texture-to-skimage-bug

The problem here is that the texture preview shows correctly but SKImage preview shows only first image.

In the code I see some sort of caching happening:

private static readonly PropertyKey<SKImage> SKImageView = new (nameof(SKImageView), typeof(TextureToSkImage));
private static readonly PropertyKey<Texture> NonSrgbTexture = new (nameof(NonSrgbTexture), typeof(TextureToSkImage));
...
texture.Tags.Set(SKImageView, image);
...

If i do:

texture.Tags.Clear();

Before sending texture, I can see that preview is starting to update, but perf drops dramatically.

If I connect DrawImage, i can clearly see that texture is updating:

Could use some guidance or direction what one should do…
I’m trying to consume it in Avalonia pipeline, and it shows same behavior as io box here

antokhio · October 1, 2025, 8:36am

Suspect the problem is here:

var image = texture.Tags.Get(SKImageView);
if (image is null)
{
   ... 
}

Basically it says “don’t update if already created”, but how to see updates on SKImage?

Elias · October 1, 2025, 9:22am

Indeed, this is an issue of the tooltip/IO box only. They assume the SKImage is immutable and only update if they get a new SKImage. In this case the texture stays the same though, therefor the SKImage returned is also the same. Maybe there’s a way to build a “new” SKImage around the same texture all the time? But that could also be misleading in other cases. Not entirely sure how to address this to be honest.

antokhio · October 1, 2025, 9:51am

@Elias Maybe we can add some sort of Force pin in meantime:

var image = texture.Tags.Get(SKImageView);
if (image is null || force)
{
   ... 
}

Also a problem that I can’t access D3D11Utils from VL.Skia.Egl if I want to override or extract, I can do this only in StandardLibs witch is not very convenient.

My latest attempt was to directly plug texture to avalonia, maybe it would be more direct way… Something like do TextureToImage inside avalonia control, but need access to D3D11Utils

Elias · October 2, 2025, 11:24am

Making D3D11Utils public is not really something we want to do. It somewhat locks us in / we can no longer modify it freely. Can you maybe provide a bigger picture about what you’re trying to do?

antokhio · October 2, 2025, 11:29am

I have an Avalonia control:

github.com/bj-rn/VL.Avalonia

VL.Avalonia/src/Skia/SkiaMediaControlBase.cs

ba367b24d


      
          
          namespace VL.Avalonia.Skia
          {
              public abstract class SkiaMediaControlBase : Control
              {
                  public SizeMode? Mode { get; set; }
                  public RectangleAnchor? Anchor { get; set; }
                  public abstract override void Render(DrawingContext context);
              }
          
              public class SkiaImageControl : SkiaMediaControlBase
              {
                  public SKImage? Image { get; set; }
                  public override void Render(DrawingContext context)
                  {
                      context.Custom(new SkiaImageDrawingOperation(Image, Bounds, Mode ?? SizeMode.AutoWidth, Anchor ?? RectangleAnchor.Center));
                      Dispatcher.UIThread.InvokeAsync(InvalidateVisual, DispatcherPriority.Background);
                  }
              }
          
              public class SkiaPictureControl : SkiaMediaControlBase

I have an Drawing Operation:

github.com/bj-rn/VL.Avalonia

VL.Avalonia/src/Skia/SkiaMediaDrawingOperationBase.cs

ba367b24d


      
          public override void Render(ImmediateDrawingContext context)
          {
              var leaseFeature = context.TryGetFeature<ISkiaSharpApiLeaseFeature>();
              if (leaseFeature != null)
              {
                  using var lease = leaseFeature.Lease();
                  var canvas = lease.SkCanvas;
          
                  canvas.Save();
          
                  if (Image != null)
                  {
                      var boundsRectangle = Bounds.FromRect();
                      var imageResolution = new Vector2(Image.Width, Image.Height);
          
                      AspectRatioUtils.FixAspectRatio(ref boundsRectangle, ref imageResolution, Mode, Anchor, out RectangleF bounds);
          
                      canvas.DrawImage(Image, bounds.ToRect().ToSKRect());
                  }
          
                  canvas.Restore();

I’m trying to use it like so:

But control only shows the first image.

Yes, I understand the consequences, but this kind of things make advanced stuff possible, I mean, I’m not expecting this to be “rock solid”, and I’m aware that it may break in future, however I don’t want to pollute repo with 10 millions deps I need to add this thing or some kind of reflection code that would still make me able to use it… I mean maybe some ExperimentalAttribute or UnstableApi that shows a warning would be sufficient…

Elias · October 2, 2025, 2:38pm

To summarize:

IO box / tooltip does not update properly for SKImage backed by mutating texture
Our DrawImage node works correctly
The canvas.DrawImage does not - are your sure it’s getting called every frame?

antokhio · October 2, 2025, 3:15pm

Yes I can see clearly that Render is called every frame… Just double check: