public IControl CreatePopover(
RectangleEdge prefferedContentEdge,
Func <PopoverState, IControl> content,
Func <PopoverState, IControl> popover)
{
var state = new PopoverState
{
IsVisible = new BehaviorSubject <bool>(false),
};
var contentFrameState = new ReplaySubject <Rectangle <Points> >(1);
var contentFrame = contentFrameState.Transpose();
var center = contentFrame.Center();
var arrow = Shapes.Rectangle(fill: Theme.PanelBackground)
.WithSize(new Size <Points>(13, 13))
.Rotate(Math.PI / 4)
;
var popoverContent = Control.Lazy(() => popover(state));
var desiredContentEdge = contentFrame.GetEdge(prefferedContentEdge)
.Add(popoverContent.DesiredSize.Height);
var desiredHostEdge = HostFrame.Switch().GetEdge(prefferedContentEdge);
var adjustedEdge = desiredContentEdge
.CombineLatest(desiredHostEdge, (a, b) => a >= b)
// Put popover on the opposite edge if there are not enough room for it on the preffered edge.
.Select(opposite => opposite ? prefferedContentEdge.Opposite() : prefferedContentEdge);
var arrowStartOffsetY = adjustedEdge
.Select(e =>
e.IsMinimal()
? contentFrame.GetEdge(e).Sub(arrow.DesiredSize.Height)
: contentFrame.GetEdge(e).Sub(4))
.Switch();
var contentStartOffsetY = adjustedEdge
.Select(e =>
e.IsMinimal()
? contentFrame.GetEdge(e).Sub(popoverContent.DesiredSize.Height).Sub(arrow.DesiredSize.Height.Div(2))
: contentFrame.GetEdge(e).Add(arrow.DesiredSize.Height.Div(2)).Sub(4))
.Switch();
var close = Command.Enabled(() => state.IsVisible.OnNext(false));
var popoverControl = Control.Lazy(() =>
Layout.Layer(self =>
{
var widthInterval = Observable.CombineLatest(
self.NativeFrame.Width,
popoverContent.DesiredSize.Width,
center.X,
(availableWidth, desiredWidth, desiredCenter) =>
{
desiredWidth += 8; // dropshadow compensation
var halfWidth = desiredWidth / 2;
return(Interval.FromOffsetLength(
offset:
desiredCenter - halfWidth <0
? 0
: desiredCenter + halfWidth> availableWidth
? availableWidth - desiredWidth
: desiredCenter - halfWidth,
length:
availableWidth.Min(desiredWidth)));
});
return(Observable.Return(
new[]
{
Shapes.Rectangle(fill: Color.AlmostTransparent).OnMouse(pressed: close),
arrow
.WithFixedPosition(
Rectangle.FromIntervals(
Interval.FromOffsetLength(center.X.Sub(arrow.DesiredSize.Width.Div(2)).Sub(4), arrow.DesiredSize.Width),
Interval.FromOffsetLength(arrowStartOffsetY, arrow.DesiredSize.Height))),
popoverContent
.WithBackground(
Shapes.Rectangle(fill: Theme.PanelBackground, cornerRadius: Observable.Return(new CornerRadius(2))))
.MakeHittable().Control
.WithFixedPosition(
Rectangle.FromIntervals(
widthInterval.Transpose(),
Interval.FromOffsetLength(contentStartOffsetY, popoverContent.DesiredSize.Height)))
}));
})
.DropShadow(radius: Observable.Return(new Points(4)), distance: Observable.Return(new Points(0.5))));
state.IsVisible.SubscribeUsing(isVisible =>
isVisible ? Popovers.AddTemporarily(popoverControl) : Disposable.Empty);
return(LayoutTracker.TrackVisualBounds(contentFrameState.OnNext, content(state)));
}