Module layer 

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

AnchorSize

Options for AnchorMode size constraints.

AnchorTransform

Options for AnchorMode::transform.

Statics

LAYERS_INSERT_CMD

Insert a layer widget on the scoped window.

LAYERS_REMOVE_CMD

Remove a layer widget on the scoped window.

Functions

adorner

P Custom layered foreground.

adorner_fn

P Custom layered foreground generated using a WidgetFn<()>.