private OrientedSize ProcessSpacingAndOverflow(double spacing, OrientedSize desiredOriented, OrientedSize availableOriented, out bool isHiddenChanged)
{
var childrenCount = Panel.Elements.Count;
var orientation = Panel.Orientation;
var target = availableOriented.Direct;
isHiddenChanged = false;
// Current length is greater than available and we have no possibility to stretch down -> mark elements as hidden
var current = 0.0;
var visible = 0.0;
var hasHiddenChildren = false;
var visibleChildrenCount = 0;
if (desiredOriented.Direct.IsGreaterThan(availableOriented.Direct))
{
var stretchOverflow = FlexElementCollection.Mount(FlexElements.Capacity);
try
{
// Process Pinned Flexible
for (var index = 0; index < childrenCount; index++)
{
var flexElement = FlexElements[index];
if (CanPinStretch(flexElement) == false)
{
continue;
}
flexElement.StretchDirection = FlexStretchDirection.Shrink;
stretchOverflow.Add(flexElement);
Panel.SetIsHidden(Panel.Elements[index], false);
}
// Process Pinned
for (var index = 0; index < childrenCount; index++)
{
var child = Panel.Elements[index];
if (child.Visibility == Visibility.Collapsed)
{
continue;
}
var flexElement = FlexElements[index];
if (CanPin(flexElement) == false)
{
continue;
}
current += flexElement.ActualLength;
current += spacing;
visible = current;
Panel.SetIsHidden(Panel.Elements[index], false);
}
// Process Hide
for (var index = 0; index < childrenCount; index++)
{
var child = Panel.Elements[index];
if (child.Visibility == Visibility.Collapsed)
{
continue;
}
visibleChildrenCount++;
var flexElement = FlexElements[index];
if (CanPin(flexElement))
{
continue;
}
current += flexElement.ActualLength;
if (CanHide(flexElement) == false)
{
isHiddenChanged |= Panel.GetIsHidden(child);
Panel.SetIsHidden(child, false);
current += spacing;
visible = current;
continue;
}
var isOverflowed = current.IsGreaterThan(target, XamlConstants.LayoutComparisonPrecision);
current += spacing;
if (isOverflowed == false)
{
visible = current;
}
isHiddenChanged |= Panel.GetIsHidden(child) != isOverflowed;
hasHiddenChildren |= isOverflowed;
Panel.SetIsHidden(child, isOverflowed);
}
if (visibleChildrenCount > 0)
{
visible = visible - spacing;
}
Panel.HasHiddenChildren = hasHiddenChildren;
// Stretch Pinned
if (visible.IsGreaterThan(availableOriented.Direct) && stretchOverflow.Count > 0)
{
var currentPinStretch = stretchOverflow.Actual;
var pinStretchTarget = (currentPinStretch - (visible - availableOriented.Direct)).Clamp(0, availableOriented.Direct);
var pinStretchDesired = stretchOverflow.Stretch(FlexStretch.Fill, pinStretchTarget, FlexDistributor.Equalizer);
if (pinStretchDesired < currentPinStretch)
{
var pinStretchIndex = 0;
for (var index = 0; index < childrenCount; index++)
{
var flexElement = FlexElements[index];
if (CanPinStretch(flexElement))
{
FlexElements[index] = stretchOverflow[pinStretchIndex++].WithStretchDirection(FlexStretchDirection.Shrink).WithMaxLength(flexElement.ActualLength);
}
else
{
FlexElements[index] = FlexElements[index].WithStretchDirection(FlexStretchDirection.Shrink).WithShrinkPriority(short.MaxValue);
}
}
FinalMeasureItems(availableOriented, spacing, true);
return(OrientedSize.Create(orientation, availableOriented.Direct, desiredOriented.Indirect));
}
}
}
finally
{
FlexElementCollection.Release(stretchOverflow);
}
return(OrientedSize.Create(orientation, visible.Clamp(0, availableOriented.Direct), desiredOriented.Indirect));
}
for (var index = 0; index < childrenCount; index++)
{
var flexElement = FlexElements[index];
var child = Panel.Elements[index];
if (child.Visibility == Visibility.Collapsed)
{
continue;
}
visibleChildrenCount++;
current += flexElement.ActualLength;
current += spacing;
Panel.SetIsHidden(Panel.Elements[index], false);
}
Panel.HasHiddenChildren = false;
visible = Math.Max(0, current);
if (visibleChildrenCount > 0)
{
visible = visible - spacing;
}
return(OrientedSize.Create(orientation, visible.Clamp(0, availableOriented.Direct), desiredOriented.Indirect));
}
private Size ArrangeCoreImpl(Size finalSize)
{
var flexPanel = Panel;
var flexPanelEx = Panel as IFlexPanelEx;
var allowMeasure = flexPanelEx?.AllowMeasureInArrange ?? false;
var orientation = flexPanel.Orientation;
var useLayoutRounding = flexPanel.UseLayoutRounding;
var spacing = GetRoundSpacing(flexPanel.Spacing, useLayoutRounding);
for (var index = 0; index < flexPanel.Elements.Count; index++)
{
FlexElements[index] = FlexElements[index].WithUIElement(flexPanel.Elements[index], orientation);
}
var currentFlexElements = FlexElementCollection.Mount(FlexElements.Capacity);
try
{
FlexElements.CopyTo(currentFlexElements);
while (true)
{
var nextArrangePass = false;
var size = new OrientedSize(orientation);
var spacingDelta = 0.0;
var finalOriented = finalSize.AsOriented(orientation);
var finalIndirect = finalOriented.Indirect;
var currentPoint = new OrientedPoint(orientation);
var childFinalOriented = new OrientedSize(orientation);
// Stretch
Stretch(currentFlexElements, spacing, finalOriented.Direct, true);
for (var index = 0; index < flexPanel.Elements.Count; index++)
{
var child = flexPanel.Elements[index];
var flexElement = currentFlexElements[index];
if (child.Visibility == Visibility.Collapsed)
{
continue;
}
if (flexPanel.GetIsHidden(child))
{
child.Arrange(XamlConstants.ZeroRect);
flexElement.ActualLength = 0.0;
currentFlexElements[index] = flexElement;
continue;
}
var desiredOriented = child.DesiredSize.AsOriented(orientation);
childFinalOriented.Direct = flexElement.ActualLength;
childFinalOriented.Indirect = Math.Max(finalIndirect, desiredOriented.Indirect);
// Arrange Child
var rect = new Rect(XamlConstants.ZeroPoint, childFinalOriented.Size).Offset(currentPoint);
if (useLayoutRounding)
{
rect = rect.LayoutRound(RoundingMode.MidPointFromZero);
}
if (_measureInfinite && allowMeasure && desiredOriented.Direct.IsGreaterThan(childFinalOriented.Direct))
{
var remeasureOriented = desiredOriented;
remeasureOriented.ChangeDirect(childFinalOriented.Direct);
child.Measure(remeasureOriented.Size);
}
child.Arrange(rect);
var arrangeSize = GetActualArrangeSize(child);
if (arrangeSize.IsEmpty == false)
{
rect.Width = arrangeSize.Width;
rect.Height = arrangeSize.Height;
}
var finalChildDirect = rect.Size().AsOriented(orientation).Direct;
if (IsArrangeFixed(flexElement) == false && finalChildDirect.IsLessThan(childFinalOriented.Direct))
{
var length = finalChildDirect;
flexElement.SetLengths(length, length, length, length);
currentFlexElements[index] = flexElement;
nextArrangePass = true;
break;
}
if (useLayoutRounding)
{
var rectSize = rect.Size().AsOriented(orientation);
flexElement.ActualLength = rectSize.Direct;
currentPoint.Direct = Math.Max(0, (currentPoint.Direct + rectSize.Direct + spacing).LayoutRound(orientation, RoundingMode.MidPointFromZero));
}
else
{
var rectSize = rect.Size().AsOriented(orientation);
flexElement.ActualLength = rectSize.Direct;
currentPoint.Direct = Math.Max(0, currentPoint.Direct + rectSize.Direct + spacing);
}
currentFlexElements[index] = flexElement;
spacingDelta += spacing;
size = size.StackSize(childFinalOriented);
}
if (nextArrangePass)
{
continue;
}
if (spacingDelta.Equals(0.0) == false)
{
size.Direct = Math.Max(0, size.Direct + spacingDelta - spacing);
}
var result = finalSize;
if (orientation == Orientation.Horizontal)
{
result.Width = flexPanel.ShouldFill(Orientation.Horizontal) ? finalSize.Width : Math.Min(finalSize.Width, size.Width);
}
else
{
result.Height = flexPanel.ShouldFill(Orientation.Vertical) ? finalSize.Height : Math.Min(finalSize.Height, size.Height);
}
return(result);
}
}
finally
{
FlexElementCollection.Release(currentFlexElements);
}
}
