Blur

Blur — a wrapper widget that applies a Gaussian-equivalent blur to its child subtree, driven by a Prop<f32> radius (in logical pixels).

Public functions

Blur

Detailed description

Built on BuildContext::set_blur, a per-node paint scope parallel to set_opacity and set_transform. The framework's render walker emits BeginBlurredSubtree { bounds, radius } before this widget's paint and EndBlurredSubtree afterwards; the renderer redirects drawing into an intermediate texture, runs a dual-Kawase blur chain at the requested radius, and composites the blurred result back into the parent pass.

Sub-perceptual radii (< 0.5 px) skip the Begin/End pair entirely so animated 0 → target_radius enable patterns have zero per-frame cost when fully off.

// Static frosted-glass backdrop:
ctx.add(Blur::new(15.0).child(modal_backdrop));

// Click-to-reveal sensitive content:
let visible = ctx.signal(false);
let radius = visible.map(|&v| if v { 0.0 } else { 12.0 });
ctx.add(Blur::new(radius).child(secret_text));

// Animated frosted-glass on modal show:
let radius = ctx.animated_signal(0.0_f32);
ctx.animate().normal().standard().to_or_snap(&radius, 15.0);
ctx.add(Blur::new(radius).child(content));

Layout semantics

Blur does not change layout. The wrapped child reports its full natural size at all blur radii; only the visual paint output is affected.

Performance

Blur is the most expensive paint scope in the framework — every enabled blur scope drives N+M+1 small render passes per frame (N downsamples, M upsamples, +1 composite). Don't put it on widgets that animate every frame at full radius. For "fade-blur on reveal" patterns, animate the radius up to a static value and leave it there. See docs/animation.md §5.8.

Density

The picture above is the widget at TargetDensity::Compact, the mouse-and-keyboard ladder. Below is the same subject on the same canvas with only the ladder changed, so what moves is the density and nothing else — where the subject no longer fits, that is what the denser targets cost it at that size. See docs/density-and-targets.md.

Touch

API reference

📖 Full rustdoc API for this module

pub struct Blur

Import: use teksilo::widgets::Blur;

Wraps a child and applies a Gaussian-equivalent blur to the entire subtree, driven by an external Prop<f32> radius (logical pixels).

#![allow(unused)]
fn main() {
pub struct Blur { /* fields */ }
}

Methods

pub fn new(radius: impl Into<Prop<f32>>) -> Self

Build a blur wrapper bound to radius (in logical pixels). Accepts any Prop<f32> source — f32, Signal<f32>, or Prop<f32>. Sub-perceptual radii (< 0.5) are a no-op.

pub fn child(mut self, widget: impl teksilo_core::IntoTeksiChild) -> Self

Inline child widget (deferred insertion).

pub fn child_opt(self, widget: Option<impl teksilo_core::IntoTeksiChild>) -> Self

Attach widget when it is Some, and do nothing when it is None.

The conditional-child form. teksu!'s if without an else lowers to this, and it is what cond.then(|| w) is for in a builder chain. None adds no arena node, so nothing is laid out, painted, or published to the accessibility tree, and a stack applies no spacing around it.