Image Measure Returns (0,0) in AutoFit Layout on Windows – Is This a Known Issue?

Hi,

I'm encountering a platform-specific issue in .NET MAUI related to image measurement inside a custom auto-sized layout. I’ve created a custom layout called AutoFitStackLayout that uses a layout manager to measure and arrange children vertically. Here's a simplified version of the layout code:

public enum HeightMode

{

    AutoFit,

    Constrained

}

public class AutoFitStackLayout : Layout

{

    public static readonly BindableProperty HeightModeProperty = BindableProperty.Create(

        nameof(HeightMode), typeof(HeightMode), typeof(AutoFitStackLayout), HeightMode.AutoFit,

        propertyChanged: (b, o, n) => ((AutoFitStackLayout)b).InvalidateMeasure());

    public HeightMode HeightMode

    {

        get => (HeightMode)GetValue(HeightModeProperty);

        set => SetValue(HeightModeProperty, value);

    }

    public static readonly BindableProperty SpacingProperty = BindableProperty.Create(

        nameof(Spacing), typeof(double), typeof(AutoFitStackLayout), 0d,

        propertyChanged: (b, o, n) => ((AutoFitStackLayout)b).InvalidateMeasure());

    public double Spacing

    {

        get => (double)GetValue(SpacingProperty);

        set => SetValue(SpacingProperty, value);

    }

    protected override ILayoutManager CreateLayoutManager()

    {

        return new AutoFitStackLayoutManager(this);

    }

    private sealed class AutoFitStackLayoutManager : ILayoutManager

    {

        private readonly AutoFitStackLayout _layout;

        public AutoFitStackLayoutManager(AutoFitStackLayout layout)

        {

            _layout = layout;

        }

        public Size Measure(double widthConstraint, double heightConstraint)

        {

            var padding = _layout.Padding;

            double horizontalPadding = padding.HorizontalThickness;

            double verticalPadding = padding.VerticalThickness;

            double availableWidthForChildren = Math.Max(0, widthConstraint - horizontalPadding);

            double computedHeight = verticalPadding;

            double computedWidth = 0;

            double childHeightConstraint = _layout.HeightMode == HeightMode.AutoFit

                ? double.PositiveInfinity

                : Math.Max(0, heightConstraint - verticalPadding);

            int visibleCount = 0;

            foreach (var child in _layout.Children)

            {

                if (child.Visibility != Visibility.Visible)

                    continue;

                var childSize = child.Measure(availableWidthForChildren, childHeightConstraint);

                computedHeight += childSize.Height;

                computedWidth = Math.Max(computedWidth, childSize.Width);

                visibleCount++;

            }

            if (visibleCount > 1)

                computedHeight += (visibleCount - 1) * _layout.Spacing;

            computedWidth += horizontalPadding;

            if (_layout.HeightMode != HeightMode.AutoFit)

            {

                computedHeight = Math.Min(computedHeight, heightConstraint);

            }

            if (_layout.HeightMode == HeightMode.AutoFit)

            {

                _layout.HeightRequest = computedHeight;

            }

            return new Size(computedWidth, computedHeight);

        }

        public Size ArrangeChildren(Rect bounds)

        {

            double x = bounds.X + _layout.Padding.Left;

            double y = bounds.Y + _layout.Padding.Top;

            double contentWidth = Math.Max(0, bounds.Width - _layout.Padding.HorizontalThickness);

            foreach (var child in _layout.Children)

            {

                if (child.Visibility != Visibility.Visible)

                    continue;

                var desired = child.DesiredSize;

                double childHeight = desired.Height;

                var rect = new Rect(x, y, contentWidth, childHeight);

                child.Arrange(rect);

                y += childHeight + _layout.Spacing;

            }

            double totalHeight = Math.Max(bounds.Height, y - bounds.Y + _layout.Padding.Bottom - _layout.Spacing);

            return new Size(bounds.Width, totalHeight);

        }

    }

}

• Issue: When I use only an Image inside this layout, the measure call consistently returns (0,0) only on Windows. On other platforms like Android and iOS, the image eventually measures correctly after a few calls.
• Workaround I find: InvalidatedMeasure after Loaded the Layout.
• Questions:
  • Is this a known issue with image measurement in MAUI on Windows?
  • Is there a recommended workaround to ensure the image is measured correctly on the first pass?
  • Could this be related to how Windows handles image loading or layout invalidation?

Any insights or suggestions would be greatly appreciated!