Backdrop

Backdrop is a full-viewport fill control typically used behind modal UI (dialogs, popups) to dim or clear the content underneath.

Backdrop

It renders a solid rune (space by default) across its bounds using the style resolved from BackdropStyle.

Key points:

It is stretched by default (HorizontalAlignment = Align.Stretch / VerticalAlignment = Align.Stretch).
It is commonly placed as the first child of a ZStack to provide a surface behind overlay content.
The fill style writes an explicit foreground so nested content that “inherits” colors (e.g. TextBlockStyle.Default) does not accidentally pick up foreground colors from whatever was rendered underneath.

Defaults

Default alignment: HorizontalAlignment = Align.Stretch, VerticalAlignment = Align.Stretch

Styling

Backdrop uses BackdropStyle from the visual environment.

BackdropStyle.Default is intended for modal dimming (it uses a dim text attribute and a theme-derived background).
BackdropStyle.ThemeBackground fills using the current theme background (useful as a generic background clearer for locally-themed regions).

Example

var overlay = new ZStack(
    new Backdrop(),
    new Dialog().Title("Modal").Content("Hello"));