zng

Module layer

source
Expand description

Window layers.

The window layers is a z-order stacking panel that fills the window content area, widgets can be inserted with a z-index that is the LayerIndex. Layers can be anchored to a normal widget, positioned relative to it with linked visibility.

The LAYERS service can be used to insert and remove layers, the example below uses it to toggle a an adorner positioned relative to the button that inserts and removes it.

use zng::prelude::*;

let inserted = var(false);
let anchored = WidgetId::new_unique();
Button! {
    on_click = hn!(inserted, |_| {
        if !inserted.get() {
            LAYERS.insert_anchored(LayerIndex::ADORNER, WIDGET.id(), layer::AnchorOffset::out_top(), Text! {
                id = anchored;
                txt = "Example";
                widget::background_color = colors::BLUE;
                layout::y = 5;
            });
        } else {
            LAYERS.remove(anchored);
        }
        inserted.set(!inserted.get());
    });
    layout::align = layout::Align::CENTER;
    child = Text!(inserted.map(|&o| if o { "Remove Layer" } else { "Insert Layer" }.into()));
}

Node operations always apply to the window content first then the layers, even with parallelism enabled, this means that layers always render over the window content and that layer widgets can react to normal widget updates within the same frame.

§Full API

See zng_wgt_layer for the full layers API.

Structs§

  • AnchorMode
    Defines what properties the layered widget takes from the anchor widget.
  • AnchorOffset
    Represents two points that position a layer widget with its anchor widget.
  • LAYERS
    Windows layers.
  • LayerIndex
    Represents a layer in a window.

Enums§

Statics§

Functions§