private void Scroll(double delta)
{
if (_selecting)
{
return;
}
_selecting = true;
var width = (float)ActualWidth;
var current = -(_selectedIndex * width);
var previous = current + width;
var next = current - width;
var maximum = next;
var minimum = previous;
if (_selectedIndex == 0)
{
minimum = current;
delta = delta > 0 ? delta : 0;
}
else if (_selectedIndex == 5)
{
maximum = current;
delta = delta < 0 ? delta : 0;
}
var offset = _layoutVisual.Offset;
var batch = _layoutVisual.Compositor.CreateScopedBatch(CompositionBatchTypes.Animation);
var animation = _layoutVisual.Compositor.CreateScalarKeyFrameAnimation();
animation.InsertKeyFrame(0, offset.X);
if (delta < 0)
{
// previous
_selectedIndex--;
_renderer?.SetPage(_selectedIndex);
animation.InsertKeyFrame(1, minimum);
}
else if (delta > 0)
{
// next
_selectedIndex++;
_renderer?.SetPage(_selectedIndex);
animation.InsertKeyFrame(1, maximum);
}
else
{
// back
animation.InsertKeyFrame(1, current);
}
_layoutVisual.StartAnimation("Offset.X", animation);
SetIndex(_selectedIndex);
batch.Completed += (s, args) =>
{
_selecting = false;
};
batch.End();
}
private void LayoutRoot_PointerWheelChanged(object sender, PointerRoutedEventArgs e)
{
if (_selecting)
{
return;
}
_selecting = true;
var point = e.GetCurrentPoint(LayoutRoot);
var delta = -point.Properties.MouseWheelDelta;
var width = (float)ActualWidth;
var current = -(_selectedIndex * width);
var previous = current + width;
var next = current - width;
var maximum = next;
var minimum = previous;
if (_selectedIndex == 0)
{
minimum = current;
delta = delta > 0 ? delta : 0;
}
else if (_selectedIndex == 5)
{
maximum = current;
delta = delta < 0 ? delta : 0;
}
var offset = _layoutVisual.Offset;
var batch = _layoutVisual.Compositor.CreateScopedBatch(CompositionBatchTypes.Animation);
var animation = _layoutVisual.Compositor.CreateScalarKeyFrameAnimation();
animation.InsertKeyFrame(0, offset.X);
if (delta < 0)
{
// previous
_selectedIndex--;
_renderer.SetPage(_selectedIndex);
animation.InsertKeyFrame(1, minimum);
}
else if (delta > 0)
{
// next
_selectedIndex++;
_renderer.SetPage(_selectedIndex);
animation.InsertKeyFrame(1, maximum);
}
else
{
// back
animation.InsertKeyFrame(1, current);
}
_layoutVisual.StartAnimation("Offset.X", animation);
batch.Completed += (s, args) =>
{
_selecting = false;
};
batch.End();
}