AttachedSide

Layered drop-shadow helper for elevated surfaces.

Composes two Shadows underneath a rounded rect:

outer — the wide soft halo (typically theme.shape.shadow_*).
inner — the sharp short-blur rim that gives the surface a clearly "lifted" edge instead of a vague glow (typically the matching theme.shape.shadow_inner_*).

The inner token's geometry (offset_y, blur, color.rgb) is used verbatim. Only color.a is modulated: the painted alpha is density × inner.color.a(), with density ∈ [0.0, 1.0] provided by the per-component shadow_density field. This keeps every visual knob in the theme while letting individual surfaces dial intensity.

Common density presets:

1.0 — tooltips (full inner-rim alpha, punchy "lift").
~0.5 — cards, popovers, menus (moderate).
0.0 — disable inner rim entirely (single-layer outer only).

Attached side

Popovers, menus and combo-box dropdowns sit attached to the widget that opened them. On the side that touches the trigger, drawing a halo would visually cut the surface off from its anchor. Pass an AttachedSide to suppress shadow on that side.

// Typical usage inside a custom widget's paint() method:
use teksilo_widgets::shadow::{paint_layered_shadow, DENSITY_SURFACE};
paint_layered_shadow(
    canvas, bounds, radius,
    &ctx.theme.shape.shadow_sm,
    &ctx.theme.shape.shadow_inner_sm,
    DENSITY_SURFACE,
    None,
);

API reference

📖 Full rustdoc API for this module

Inner-rim alpha multiplier for tooltips — full intensity for maximum lift.

#![allow(unused)]
fn main() {
pub const DENSITY_TOOLTIP: f32 = 1.0;
}

`pub const DENSITY_SURFACE`

Inner-rim alpha multiplier for cards, popovers, and menus — moderate lift.

#![allow(unused)]
fn main() {
pub const DENSITY_SURFACE: f32 = 0.5;
}

`pub const DENSITY_DIALOG`

Inner-rim alpha multiplier for snackbars and dialogs — subtle lift.

#![allow(unused)]
fn main() {
pub const DENSITY_DIALOG: f32 = 0.3;
}

`pub enum AttachedSide`

Which geometric edge of the surface is attached to its trigger and should have shadow drawing suppressed on that side. Geometric (Top / Bottom / Left / Right), not RTL-aware — callers working in Leading/Trailing terms must resolve to a geometric side using the active layout direction before calling.

#![allow(unused)]
fn main() {
pub enum AttachedSide { /* variants */ }
}

Variants

Top — Suppress the shadow halo on the top edge (e.g. a dropdown opening downward).
Bottom — Suppress the shadow halo on the bottom edge (e.g. a popover opening upward).
Left — Suppress the shadow halo on the left edge.
Right — Suppress the shadow halo on the right edge.

`pub fn paint_layered_shadow(...)`

Paint a two-layer drop shadow behind a rounded rect.

The outer shadow is drawn unchanged. If density × inner.color.a() is above the sub-perceptual threshold (1/255), the inner shadow is drawn on top with its alpha scaled by density. This gives a "lift" look — a wide soft halo with a sharp close rim.

When attached is Some(side), both shadow draws are clipped so the penumbra on that side is hidden — matching the visual where the surface is attached to its anchor (popover under its trigger, dropdown under its combo box, etc.).

If both layers would be sub-perceptual (e.g. theme has zero alphas or density of 0), this function returns without emitting any draw commands.

// In a widget's paint() method:
use teksilo_widgets::shadow::{paint_layered_shadow, AttachedSide, DENSITY_SURFACE};
paint_layered_shadow(
    canvas, bounds, radius,
    &ctx.theme.shape.shadow_sm, &ctx.theme.shape.shadow_inner_sm,
    DENSITY_SURFACE, None,
);

#![allow(unused)]
fn main() {
pub fn paint_layered_shadow(
    canvas: &mut Canvas,
    bounds: Rect,
    radius: CornerRadius,
    outer: &Shadow,
    inner: &Shadow,
    density: f32,
    attached: Option<AttachedSide>,
);
}

Teksilo Documentation