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

[MuthukumarMadasamy]

Hi everyone,
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:

// AutoFitStackLayout.cs
using Microsoft.Maui.Layouts;
using System;

namespace AutoFitLayoutSample
{
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!

[stephenquan]

I don't know if this is relevant, but in VerticalStackLayoutManager.cs, the child-filtering guard differs from the one in your code.

// From VerticalStackLayoutManager.cs
				if (child.Visibility == Visibility.Collapsed)
				{
					continue;
				}

// AutoFitStackLayout
                if (child.Visibility != Visibility.Visible)
                    continue;