protected void ArrangeChildOverride(View view, Rect frame)
{
view.Arranged = frame;
view.LayoutSlotWithMarginsAndAlignments = frame;
LayoutInformation.SetLayoutSlot(view, frame);
}
public void Arrange(Rect finalRect)
{
if (!(this is FrameworkElement))
{
return;
}
if (Visibility == Visibility.Collapsed || finalRect == default)
{
LayoutInformation.SetLayoutSlot(this, finalRect);
HideVisual();
_isArrangeValid = true;
return;
}
if (!_isArrangeValid || finalRect != LayoutSlot)
{
ShowVisual();
// We must store the updated slot before natively arranging the element,
// so the updated value can be read by indirect code that is being invoked on arrange.
// For instance, the EffectiveViewPort computation reads that value to detect slot changes (cf. PropagateEffectiveViewportChange)
LayoutInformation.SetLayoutSlot(this, finalRect);
ArrangeCore(finalRect);
_isArrangeValid = true;
}
}
public void Arrange(Rect finalRect)
{
if (!_isFrameworkElement)
{
return;
}
if (Visibility == Visibility.Collapsed
// If the layout is clipped, and the arranged size is empty, we can skip arranging children
// This scenario is particularly important for the Canvas which always sets its desired size
// zero, even after measuring its children.
|| (finalRect == default && (this is not ICustomClippingElement clipElement || clipElement.AllowClippingToLayoutSlot)))
{
LayoutInformation.SetLayoutSlot(this, finalRect);
HideVisual();
ClearLayoutFlags(LayoutFlag.ArrangeDirty);
return;
}
if (!IsArrangeDirty && finalRect == LayoutSlot)
{
return; // Calling Arrange would be a waste of CPU time here.
}
if (IsVisualTreeRoot)
{
ArrangeVisualTreeRoot(finalRect);
}
else
{
// If possible we avoid the try/finally which might be costly on some platforms
DoArrange(finalRect);
}
}
public void Arrange(Rect finalRect)
{
if (!(this is FrameworkElement))
{
return;
}
if (Visibility == Visibility.Collapsed
// If the layout is clipped, and the arranged size is empty, we can skip arranging children
// This scenario is particularly important for the Canvas which always sets its desired size
// zero, even after measuring its children.
|| (finalRect == default && (this is ICustomClippingElement clipElement ? clipElement.AllowClippingToLayoutSlot : true)))
{
LayoutInformation.SetLayoutSlot(this, finalRect);
HideVisual();
_isArrangeValid = true;
return;
}
if (_isArrangeValid && finalRect == LayoutSlot)
{
return;
}
if (IsVisualTreeRoot)
{
ArrangeVisualTreeRoot(finalRect);
}
else
{
// If possible we avoid the try/finally which might be costly on some platforms
DoArrange(finalRect);
}
}
public override void LayoutSubviews()
{
try
{
try
{
_inLayoutSubviews = true;
if (IsMeasureDirty)
{
// Add back the Margin (which is normally 'outside' the view's bounds) - the layouter will subtract it again
var availableSizeWithMargins = Bounds.Size.Add(Margin);
XamlMeasure(availableSizeWithMargins);
}
//if (IsArrangeDirty) // commented until the MEASURE_DIRTY_PATH is properly implemented for iOS
{
ClearLayoutFlags(LayoutFlag.ArrangeDirty);
OnBeforeArrange();
Rect finalRect;
var parent = Superview;
if (parent is UIElement ||
parent is ISetLayoutSlots
// In the case of ListViewItem inside native list, its parent's parent is ListViewBaseInternalContainer
|| parent?.Superview is ISetLayoutSlots
)
{
finalRect = LayoutSlotWithMarginsAndAlignments;
}
else
{
// Here the "arrange" is coming from a native element,
// so we convert those measurements to logical ones.
finalRect = RectFromUIRect(Frame);
// We also need to set the LayoutSlot as it was not by the parent.
// Note: This is only an approximation of the LayoutSlot as margin and alignment might already been applied at this point.
LayoutInformation.SetLayoutSlot(this, finalRect);
LayoutSlotWithMarginsAndAlignments = finalRect;
}
_layouter.Arrange(finalRect);
OnAfterArrange();
}
}
finally
{
_inLayoutSubviews = false;
}
}
catch (Exception e)
{
this.Log().Error($"Layout failed in {GetType()}", e);
}
}
public override void LayoutSubviews()
{
if (Visibility == Visibility.Collapsed)
{
// //Don't layout collapsed views
return;
}
try
{
try
{
_inLayoutSubviews = true;
if (IsMeasureDirty)
{
// Add back the Margin (which is normally 'outside' the view's bounds) - the layouter will subtract it again
XamlMeasure(Bounds.Size.Add(Margin));
}
OnBeforeArrange();
Rect finalRect;
var parent = Superview;
if (parent is UIElement || parent is ISetLayoutSlots)
{
finalRect = LayoutSlotWithMarginsAndAlignments;
}
else
{
// Here the "arrange" is coming from a native element,
// so we convert those measurements to logical ones.
finalRect = RectFromUIRect(Frame);
// We also need to set the LayoutSlot as it was not by the parent.
// Note: This is only an approximation of the LayoutSlot as margin and alignment might already been applied at this point.
LayoutInformation.SetLayoutSlot(this, finalRect);
LayoutSlotWithMarginsAndAlignments = finalRect;
}
_layouter.Arrange(finalRect);
OnAfterArrange();
}
finally
{
_inLayoutSubviews = false;
IsArrangeDirty = false;
}
}
catch (Exception e)
{
this.Log().Error($"Layout failed in {GetType()}", e);
}
}
private void DoArrange(Rect finalRect)
{
ShowVisual();
// We must store the updated slot before natively arranging the element,
// so the updated value can be read by indirect code that is being invoked on arrange.
// For instance, the EffectiveViewPort computation reads that value to detect slot changes (cf. PropagateEffectiveViewportChange)
LayoutInformation.SetLayoutSlot(this, finalRect);
ArrangeCore(finalRect);
_isArrangeValid = true;
}
private void DoArrange(Rect finalRect)
{
var isFirstArrange = !IsLayoutFlagSet(LayoutFlag.FirstArrangeDone);
var isDirty =
isFirstArrange ||
IsArrangeDirty ||
finalRect != LayoutSlot;
if (!isDirty && !IsArrangeDirtyPath)
{
return; // Nothing do to
}
var remainingTries = MaxLayoutIterations;
while (--remainingTries > 0)
{
if (IsMeasureDirtyOrMeasureDirtyPath)
{
DoMeasure(LastAvailableSize);
}
if (isDirty)
{
ShowVisual();
// We must store the updated slot before natively arranging the element,
// so the updated value can be read by indirect code that is being invoked on arrange.
// For instance, the EffectiveViewPort computation reads that value to detect slot changes (cf. PropagateEffectiveViewportChange)
LayoutInformation.SetLayoutSlot(this, finalRect);
// We must reset the flag **BEFORE** doing the actual arrange, so the elements are able to re-invalidate themselves
ClearLayoutFlags(LayoutFlag.ArrangeDirty | LayoutFlag.ArrangeDirtyPath);
ArrangeCore(finalRect);
SetLayoutFlags(LayoutFlag.FirstArrangeDone);
break;
}
else if (IsArrangeDirtyPath)
{
ClearLayoutFlags(LayoutFlag.ArrangeDirtyPath);
var children = GetChildren().GetEnumerator();
while (children.MoveNext())
{
var child = children.Current;
if (child is { IsArrangeDirtyOrArrangeDirtyPath : true })
private void DoArrange(Rect finalRect)
{
ShowVisual();
// We must store the updated slot before natively arranging the element,
// so the updated value can be read by indirect code that is being invoked on arrange.
// For instance, the EffectiveViewPort computation reads that value to detect slot changes (cf. PropagateEffectiveViewportChange)
LayoutInformation.SetLayoutSlot(this, finalRect);
// We must reset the flag **BEFORE** doing the actual arrange, so the elements are able to re-invalidate themselves
ClearLayoutFlags(LayoutFlag.ArrangeDirty);
ArrangeCore(finalRect);
}
public void When_UpdateLayout_Then_TreeNotMeasuredUsingCachedValue()
{
if (Window.Current.RootElement is Panel root)
{
var sut = new Grid
{
HorizontalAlignment = HorizontalAlignment.Stretch,
VerticalAlignment = VerticalAlignment.Stretch
};
var originalRootAvailableSize = LayoutInformation.GetAvailableSize(root);
var originalRootDesiredSize = LayoutInformation.GetDesiredSize(root);
var originalRootLayoutSlot = LayoutInformation.GetLayoutSlot(root);
Size availableSize;
Rect layoutSlot;
try
{
LayoutInformation.SetAvailableSize(root, default);
LayoutInformation.SetDesiredSize(root, default);
LayoutInformation.SetLayoutSlot(root, default);
root.Children.Add(sut);
sut.UpdateLayout();
availableSize = LayoutInformation.GetAvailableSize(sut);
layoutSlot = LayoutInformation.GetLayoutSlot(sut);
}
finally
{
LayoutInformation.SetAvailableSize(root, originalRootAvailableSize);
LayoutInformation.SetDesiredSize(root, originalRootDesiredSize);
LayoutInformation.SetLayoutSlot(root, originalRootLayoutSlot);
root.Children.Remove(sut);
try { root.UpdateLayout(); }
catch { } // Make sure to restore visual tree if test has failed!
}
Assert.AreNotEqual(default, availableSize);
public void Arrange(Rect finalRect)
{
if (!(this is FrameworkElement))
{
return;
}
if (Visibility == Visibility.Collapsed || finalRect == default)
{
LayoutInformation.SetLayoutSlot(this, finalRect);
HideVisual();
_isArrangeValid = true;
return;
}
if (_isArrangeValid && finalRect == LayoutSlot)
{
return;
}
if (IsVisualTreeRoot)
{
try
{
_isLayoutingVisualTreeRoot = true;
DoArrange(finalRect);
}
finally
{
_isLayoutingVisualTreeRoot = false;
}
}
else
{
// If possible we avoid the try/finally which might be costly on some platforms
DoArrange(finalRect);
}
}
protected override void OnLayoutCore(bool changed, int left, int top, int right, int bottom)
{
try
{
base.OnLayoutCore(changed, left, top, right, bottom);
Rect finalRect;
if (TransientArrangeFinalRect is Rect tafr)
{
// If the parent element is from managed code,
// we can recover the "Arrange" with double accuracy.
// We use that because the conversion to android's "int" is loosing too much precision.
finalRect = tafr;
}
else
{
// Here the "arrange" is coming from a native element,
// so we convert those measurements to logical ones.
finalRect = new Rect(left, top, right - left, bottom - top).PhysicalToLogicalPixels();
// We also need to set the LayoutSlot as it was not set by the parent.
// Note: This is only an approximation of the LayoutSlot as margin and alignment might already been applied at this point.
LayoutInformation.SetLayoutSlot(this, finalRect);
LayoutSlotWithMarginsAndAlignments = finalRect;
}
if (this.Log().IsEnabled(Microsoft.Extensions.Logging.LogLevel.Debug))
{
this.Log().DebugFormat(
"[{0}/{1}] OnLayoutCore({2}, {3}, {4}, {5}) (parent: {5},{6})",
GetType(),
Name,
left, top, right, bottom,
MeasuredWidth,
MeasuredHeight
);
}
var previousSize = AssignedActualSize;
AssignedActualSize = finalRect.Size;
if (
// If the layout has changed, but the final size has not, this is just a translation.
// So unless there was a layout requested, we can skip arranging the children.
(changed && _lastLayoutSize != finalRect.Size)
// Even if nothing changed, but a layout was requested, arrange the children.
|| IsLayoutRequested
)
{
_lastLayoutSize = finalRect.Size;
OnBeforeArrange();
_layouter.Arrange(finalRect);
OnAfterArrange();
}
if (previousSize != finalRect.Size)
{
SizeChanged?.Invoke(this, new SizeChangedEventArgs(this, previousSize, finalRect.Size));
_renderTransform?.UpdateSize(finalRect.Size);
}
}
catch (Exception e)
{
Application.Current.RaiseRecoverableUnhandledExceptionOrLog(e, this);
}
}
