public UIElement Interpret(MenuViewMessage state)
{
var canvas = new Canvas {
HorizontalAlignment = HorizontalAlignment.Stretch
};
if (state == null)
{
return(canvas);
}
double position = state.Position;
double topOffset = Height / 2 - itemHeight * position;
int firstVisibleChildIdx = IntegerUtils.Clamp(
(int)Math.Floor(-(itemHeight + topOffset) / itemHeight),
0, state.Items.Count);
int lastVisibleChildIdx = IntegerUtils.Clamp(
(int)Math.Ceiling((Height - topOffset) / itemHeight),
0, state.Items.Count - 1);
for (int childIdx = firstVisibleChildIdx; childIdx <= lastVisibleChildIdx; ++childIdx)
{
var item = state.Items[childIdx];
var childElem = CreateItem(item);
canvas.Children.Add(childElem);
Canvas.SetTop(childElem, topOffset + itemHeight * childIdx);
childElem.Width = Width;
}
return(canvas);
}
public void TestClamp()
{
Assert.AreEqual(2, IntegerUtils.Clamp(1, 2, 4));
Assert.AreEqual(2, IntegerUtils.Clamp(2, 2, 4));
Assert.AreEqual(3, IntegerUtils.Clamp(3, 2, 4));
Assert.AreEqual(4, IntegerUtils.Clamp(4, 2, 4));
Assert.AreEqual(4, IntegerUtils.Clamp(5, 2, 4));
}
private int ToIndexClamped(Size2 size, int x, int y)
{
return(ToIndex(size,
IntegerUtils.Clamp(x, 0, size.Width - 1),
IntegerUtils.Clamp(y, 0, size.Height - 1)));
}
