protected override void OnItemLayout(LayoutItemEventArgs args)
{
AnimatedWrapPanelItemState state;
var accuState =
args.AccumulateState as WrapPanelAccumulatedItemState
?? new WrapPanelAccumulatedItemState (args.LayoutItemState, AnimationDuration);
if (Orientation == Orientation.Vertical)
{
if (accuState.NextY + args.DesiredSize.Height > args.AvailableSize.Height)
{
accuState.X = accuState.NextX;
accuState.Y = 0;
accuState.NextX = 0;
}
else
{
accuState.Y = accuState.NextY;
}
accuState.NextX = Math.Max (accuState.NextX, accuState.X + args.DesiredSize.Width);
accuState.NextY = accuState.Y + args.DesiredSize.Height;
}
else
{
if (accuState.NextX + args.DesiredSize.Width > args.AvailableSize.Width)
{
accuState.X = 0;
accuState.Y = accuState.NextY;
accuState.NextY = 0;
}
else
{
accuState.X = accuState.NextX;
}
accuState.NextX = accuState.X + args.DesiredSize.Width;
accuState.NextY = Math.Max (accuState.NextY, accuState.Y + args.DesiredSize.Height);
}
args.AccumulateState = accuState;
var newX = accuState.X;
var newY = accuState.Y;
switch (args.LayoutItemState)
{
case LayoutItemState.IsMeasuring:
state =
new AnimatedWrapPanelItemState
{
TranslateTransform =
new TranslateTransform
{
X = newX,
Y = newY,
},
};
break;
case LayoutItemState.IsArranging:
state = args.State as AnimatedWrapPanelItemState;
if (state == null)
{
state =
new AnimatedWrapPanelItemState
{
TranslateTransform =
new TranslateTransform
{
X = newX,
Y = newY,
},
};
AnimateOpacity (args, accuState);
}
else if (
newX != state.TranslateTransform.X
|| newY != state.TranslateTransform.Y
)
{
AnimateOpacity (args, accuState);
}
if (newX != state.TranslateTransform.X)
{
accuState.ShowStoryboard.AnimateProperty (
state.TranslateTransform,
TranslateTransform.XProperty,
TimeSpan.Zero,
newX
);
}
if (newY != state.TranslateTransform.Y)
{
accuState.ShowStoryboard.AnimateProperty (
state.TranslateTransform,
TranslateTransform.YProperty,
TimeSpan.Zero,
newY
);
}
break;
default:
throw new ArgumentOutOfRangeException ();
}
args.State = state;
args.Transform = state.TranslateTransform;
}
protected abstract void OnItemLayout(LayoutItemEventArgs layoutItemEventArgs);
protected override Size ArrangeOverride(Size finalSize)
{
if (Children == null || Children.Count < 1)
{
return finalSize;
}
object accumulatedState = null;
try
{
var count = Children.Count;
for (var iter = 0; iter < Children.Count; ++iter)
{
var child = Children[iter];
var desiredSize = child.DesiredSize;
var args = new LayoutItemEventArgs
{
LayoutItemState = LayoutItemState.IsArranging,
UiElement = child,
AccumulateState = accumulatedState,
State = GetUIElementState (child),
AvailableSize = finalSize,
DesiredSize = desiredSize,
Count = count,
Index = iter,
Transform = child.RenderTransform,
};
OnItemLayout (args);
accumulatedState = args.AccumulateState;
child.RenderTransform = args.Transform ?? s_identityTransform;
SetUIElementState (child, args.State);
child.Arrange (new Rect (0, 0, child.DesiredSize.Width, child.DesiredSize.Height));
}
return finalSize;
}
finally
{
Common.Dispose (accumulatedState);
}
}
protected override Size MeasureOverride(Size availableSize)
{
if (Children == null || Children.Count < 1)
{
return new Size (0, 0);
}
var resultingRect = new Rect ();
object accumulatedState = null;
try
{
var count = Children.Count;
for (var iter = 0; iter < count; ++iter)
{
var child = Children[iter];
child.Measure (availableSize);
var desiredSize = child.DesiredSize;
var args = new LayoutItemEventArgs
{
LayoutItemState = LayoutItemState.IsMeasuring,
UiElement = child,
AccumulateState = accumulatedState,
State = GetUIElementState (child),
AvailableSize = availableSize,
DesiredSize = desiredSize,
Count = count,
Index = iter,
Transform = child.RenderTransform,
};
OnItemLayout (args);
accumulatedState = args.AccumulateState;
var childRect = (args.Transform ?? s_identityTransform).TransformBounds (new Rect (0, 0, desiredSize.Width, desiredSize.Height));
resultingRect.Union (childRect);
}
return availableSize.Merge (resultingRect.ToSize ());
}
finally
{
Common.Dispose (accumulatedState);
}
}
void AnimateOpacity(LayoutItemEventArgs args, WrapPanelAccumulatedItemState accuState)
{
args.UiElement.Opacity = 0;
accuState.ShowStoryboard.AnimateProperty (
args.UiElement,
OpacityProperty,
AnimationDuration,
1.0,
0.0
);
}