/// <summary>
/// Implements custom measure logic.
/// </summary>
/// <param name="constraint">Constraint to measure within.</param>
/// <returns>Desired size.</returns>
protected override Size MeasureOverride(Size constraint)
{
var bands = Bands;
var orientation = Orientation;
// Calculate the Size to Measure children with
var constrainedLength = new OrientedLength(orientation, constraint);
constrainedLength.PrimaryLength = double.PositiveInfinity;
constrainedLength.SecondaryLength /= bands;
var availableLength = constrainedLength.Size;
// Measure each child
var band = 0;
var levelLength = new OrientedLength(orientation);
var usedLength = new OrientedLength(orientation);
foreach (UIElement child in Children)
{
child.Measure(availableLength);
// Update for the band/level of this child
var desiredLength = new OrientedLength(orientation, child.DesiredSize);
levelLength.PrimaryLength = Math.Max(levelLength.PrimaryLength, desiredLength.PrimaryLength);
levelLength.SecondaryLength += desiredLength.SecondaryLength;
// Move to the next band
band = (band + 1) % bands;
if (0 == band)
{
// Update for the complete level; reset for the next one
usedLength.PrimaryLength += levelLength.PrimaryLength;
usedLength.SecondaryLength = Math.Max(usedLength.SecondaryLength, levelLength.SecondaryLength);
levelLength.PrimaryLength = 0;
levelLength.SecondaryLength = 0;
}
}
// Update for the partial level at the end
usedLength.PrimaryLength += levelLength.PrimaryLength;
usedLength.SecondaryLength = Math.Max(usedLength.SecondaryLength, levelLength.SecondaryLength);
// Return the used size
return usedLength.Size;
}
/// <summary>
/// Implements custom arrange logic.
/// </summary>
/// <param name="arrangeSize">Size to arrange to.</param>
/// <returns>Used size.</returns>
protected override Size ArrangeOverride(Size arrangeSize)
{
var bands = Bands;
var orientation = Orientation;
var count = Children.Count;
// Prepare the Rect to arrange children with
var arrangeLength = new OrientedLength(orientation, arrangeSize);
arrangeLength.SecondaryLength /= bands;
// Arrange each child
for (var i = 0; i < count; i += bands)
{
// Determine the length of the current level
arrangeLength.PrimaryLength = 0;
arrangeLength.SecondaryOffset = 0;
for (var band = 0; (band < bands) && (i + band < count); band++)
{
var desiredLength = new OrientedLength(orientation, Children[i + band].DesiredSize);
arrangeLength.PrimaryLength = Math.Max(arrangeLength.PrimaryLength, desiredLength.PrimaryLength);
}
// Arrange each band within the level
for (var band = 0; (band < bands) && (i + band < count); band++)
{
Children[i + band].Arrange(arrangeLength.Rect);
arrangeLength.SecondaryOffset += arrangeLength.SecondaryLength;
}
// Update for the next level
arrangeLength.PrimaryOffset += arrangeLength.PrimaryLength;
}
// Return the arranged size
return arrangeSize;
}