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Sep 12, 2025
Merged

Avoid useless measure passes on iOS #31485

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9efb9fe
Avoid useless measure passes on iOS
albyrock87 Sep 4, 2025
712dc29
Refactor condition for simplicty
albyrock87 Sep 10, 2025
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6 changes: 4 additions & 2 deletions src/Controls/tests/DeviceTests/Elements/Button/ButtonTests.iOS.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -74,9 +74,11 @@ await InvokeOnMainThreadAsync(async () =>

// Wait for image to load and force the grid to measure itself again
await Task.Delay(1000);
#pragma warning disable CS0618 // Type or member is obsolete

// The layout and buttons are not connected to a window, so the measure invalidation won't propagate.
// Therefore, we have to invalidate and measure the layout manually.
layout.InvalidateMeasure();
layout.Measure(double.PositiveInfinity, double.PositiveInfinity);
#pragma warning restore CS0618 // Type or member is obsolete

await handler.ToPlatform().AssertContainsColor(Colors.Blue, MauiContext); // Grid renders
await handler.ToPlatform().AssertContainsColor(Colors.Red, MauiContext); // Image within button renders
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8 changes: 4 additions & 4 deletions src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue25671.cs
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Expand Up @@ -42,13 +42,13 @@ public async Task LayoutPassesShouldNotIncrease()
var arrangePasses = int.Parse(match.Groups[2].Value);

#if IOS
var maxMeasurePasses = 225;
var maxArrangePasses = 247;
var maxMeasurePasses = 203;
var maxArrangePasses = 214;

if (App.FindElement("HeadingLabel").GetText() == "CollectionViewHandler2")
{
maxMeasurePasses = 380;
maxArrangePasses = 295;
maxMeasurePasses = 373;
maxArrangePasses = 276;
}
#elif ANDROID
const int maxMeasurePasses = 353;
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51 changes: 42 additions & 9 deletions src/Core/src/Platform/iOS/MauiView.cs
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Expand Up @@ -35,6 +35,13 @@ public abstract class MauiView : UIView, ICrossPlatformLayoutBacking, IVisualTre
/// </summary>
double _lastMeasureWidth = double.NaN;

/// <summary>
/// Cached measured cross-platform size from the last measure operation tight to <see cref="_lastMeasureWidth"/> and <see cref="_lastMeasureHeight"/>.
/// Used to avoid redundant measure calls when constraints haven't changed.
/// NaN indicates no previous measure has been performed.
/// </summary>
Size? _lastMeasuredSize;

/// <summary>
/// Current safe area padding values (top, left, bottom, right) in device-independent units.
/// These values represent the insets needed to avoid system UI elements like status bars,
Expand Down Expand Up @@ -348,15 +355,34 @@ SafeAreaPadding GetAdjustedSafeAreaInsets()
/// <returns>True if the cached measure is still valid, false otherwise</returns>
protected bool IsMeasureValid(double widthConstraint, double heightConstraint)
{
return !HasFixedConstraints
&& widthConstraint == _lastMeasureWidth
return widthConstraint == _lastMeasureWidth
&& heightConstraint == _lastMeasureHeight;
}

/// <summary>
/// Caches the measure constraints and the resulting measured size from the last measure operation.
/// </summary>
/// <param name="widthConstraint">The width constraint used.</param>
/// <param name="heightConstraint">The height constraint used.</param>
[Obsolete("Use CacheMeasureConstraints(double widthConstraint, double heightConstraint, Size measuredSize) instead.")]
protected void CacheMeasureConstraints(double widthConstraint, double heightConstraint)
{
_lastMeasureWidth = widthConstraint;
_lastMeasureHeight = heightConstraint;
_lastMeasuredSize = null;
}

/// <summary>
/// Caches the measure constraints and the resulting measured size from the last measure operation.
/// </summary>
/// <param name="widthConstraint">The width constraint used.</param>
/// <param name="heightConstraint">The height constraint used.</param>
/// <param name="measuredSize">The resulting measured cross-platform size.</param>
protected void CacheMeasureConstraints(double widthConstraint, double heightConstraint, Size measuredSize)
{
_lastMeasureWidth = widthConstraint;
_lastMeasureHeight = heightConstraint;
_lastMeasuredSize = measuredSize;
}

/// <summary>
Expand All @@ -366,7 +392,7 @@ protected void CacheMeasureConstraints(double widthConstraint, double heightCons
/// <returns>True if the view has been measured, false otherwise</returns>
bool HasBeenMeasured()
{
return !double.IsNaN(_lastMeasureWidth) && !double.IsNaN(_lastMeasureHeight);
return _lastMeasuredSize.HasValue;
}

/// <summary>
Expand All @@ -378,6 +404,7 @@ protected void InvalidateConstraintsCache()
{
_lastMeasureWidth = double.NaN;
_lastMeasureHeight = double.NaN;
_lastMeasuredSize = null;
}

public ICrossPlatformLayout? CrossPlatformLayout
Expand Down Expand Up @@ -446,9 +473,14 @@ public override CGSize SizeThatFits(CGSize size)
var widthConstraint = (double)size.Width;
var heightConstraint = (double)size.Height;

var crossPlatformSize = CrossPlatformMeasure(widthConstraint, heightConstraint);
if (IsMeasureValid(widthConstraint, heightConstraint) && _lastMeasuredSize is { } crossPlatformSize)
{
return crossPlatformSize.ToCGSize();
}

crossPlatformSize = CrossPlatformMeasure(widthConstraint, heightConstraint);

CacheMeasureConstraints(widthConstraint, heightConstraint);
CacheMeasureConstraints(widthConstraint, heightConstraint, crossPlatformSize);

return crossPlatformSize.ToCGSize();
}
Expand Down Expand Up @@ -499,11 +531,12 @@ public override void LayoutSubviews()
// imposed by the parent (i.e. scroll view) with the current bounds, except when our bounds are fixed by constraints.
// But we _do_ need LayoutSubviews to make a measurement pass if the parent is something else (for example,
// the window); there's no guarantee that SizeThatFits has been called in that case.
if (!IsMeasureValid(widthConstraint, heightConstraint) && !this.IsFinalMeasureHandledBySuperView() ||
!HasBeenMeasured() && HasFixedConstraints)
var hasFixedConstraints = HasFixedConstraints;
if ((hasFixedConstraints || !IsMeasureValid(widthConstraint, heightConstraint)) && !this.IsFinalMeasureHandledBySuperView() ||
hasFixedConstraints && !HasBeenMeasured())
{
CrossPlatformMeasure(widthConstraint, heightConstraint);
CacheMeasureConstraints(widthConstraint, heightConstraint);
var crossPlatformSize = CrossPlatformMeasure(widthConstraint, heightConstraint);
CacheMeasureConstraints(widthConstraint, heightConstraint, crossPlatformSize);
}

CrossPlatformArrange(bounds);
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1 change: 1 addition & 0 deletions src/Core/src/PublicAPI/net-ios/PublicAPI.Unshipped.txt
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Expand Up @@ -59,6 +59,7 @@ Microsoft.Maui.Platform.MauiTimePicker.UpdateTime(System.TimeSpan? time) -> void
*REMOVED*Microsoft.Maui.Platform.MauiWebViewNavigationDelegate.DidFailNavigation(WebKit.WKWebView! webView, WebKit.WKNavigation! navigation, Foundation.NSError! error) -> void
*REMOVED*Microsoft.Maui.Platform.MauiWebViewNavigationDelegate.DidFailProvisionalNavigation(WebKit.WKWebView! webView, WebKit.WKNavigation! navigation, Foundation.NSError! error) -> void
*REMOVED*Microsoft.Maui.Platform.MauiWebViewNavigationDelegate.DidFinishNavigation(WebKit.WKWebView! webView, WebKit.WKNavigation! navigation) -> void
Microsoft.Maui.Platform.MauiView.CacheMeasureConstraints(double widthConstraint, double heightConstraint, Microsoft.Maui.Graphics.Size measuredSize) -> void
Microsoft.Maui.Platform.TextInputExtensions
Microsoft.Maui.Platform.UIApplicationExtensions
Microsoft.Maui.SafeAreaEdges
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1 change: 1 addition & 0 deletions src/Core/src/PublicAPI/net-maccatalyst/PublicAPI.Unshipped.txt
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Expand Up @@ -61,6 +61,7 @@ Microsoft.Maui.Platform.MauiTimePicker.UpdateTime(System.TimeSpan? time) -> void
*REMOVED*Microsoft.Maui.Platform.MauiWebViewNavigationDelegate.DidFailNavigation(WebKit.WKWebView! webView, WebKit.WKNavigation! navigation, Foundation.NSError! error) -> void
*REMOVED*Microsoft.Maui.Platform.MauiWebViewNavigationDelegate.DidFailProvisionalNavigation(WebKit.WKWebView! webView, WebKit.WKNavigation! navigation, Foundation.NSError! error) -> void
*REMOVED*Microsoft.Maui.Platform.MauiWebViewNavigationDelegate.DidFinishNavigation(WebKit.WKWebView! webView, WebKit.WKNavigation! navigation) -> void
Microsoft.Maui.Platform.MauiView.CacheMeasureConstraints(double widthConstraint, double heightConstraint, Microsoft.Maui.Graphics.Size measuredSize) -> void
Microsoft.Maui.Platform.TextInputExtensions
Microsoft.Maui.Platform.UIApplicationExtensions
Microsoft.Maui.SafeAreaEdges
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