Scale

Scale — wraps a child and animates a uniform 2D scale on its entire subtree when an external Prop<bool> toggles. Drives a progress: Signal<f32> ∈ [0, 1] (0 = invisible, 1 = at rest) and applies it as a centered (or origin-pivoted) scale transform via BuildContext::set_transform — the renderer's transform stack composes it onto the subtree.

let visible = ctx.signal(false);
ctx.add(Scale::new(visible.clone()).child(card));
visible.set(true);   // scale-in around the slot center

Two layout modes

Visual-only (default) — reflow=false. The slot stays at the child's natural size at all scale values; only the visual content shrinks/grows around the chosen origin. Use for: overlay enter/exit, "boop" feedback on a Card, focus emphasis. Pair with Center origin (the default).
Reflow — .reflow(true). The wrapper's layout_response returns child_size * progress, so siblings reflow as the child shrinks to nothing. The visual content scales by the same factor, fitting exactly within the shrunken slot. Use for: a Card that disappears by shrinking with surrounding cards filling the gap. Pair with TopLeading origin (so the visual stays anchored at the slot's top-left as it shrinks — otherwise the visual drifts while the slot shrinks).

Why this isn't just `Collapse`

Collapse animates only one axis (height by default) and "wipes" content via clipping — text inside stays at full size, only the visible portion shrinks. Scale shrinks uniformly on both axes, and text/icons visually get smaller. Different visual vocabulary, different use cases.

Reduced motion

Honours prefers-reduced-motion: snaps progress to its end value (visible / hidden) instead of tweening.

Builder methods at a glance

reflow, origin, duration, easing, child, child_id

API reference

📖 Full rustdoc API for this module

`pub enum ScaleOrigin`

Pivot point for the scale matrix, expressed relative to the wrapper's slot rectangle.

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

Variants

Center — Scale around the centre of the slot. Default for visual-only mode.
TopLeading — Pin the top-leading corner; content grows/shrinks toward the bottom-trailing.
TopTrailing — Pin the top-trailing corner; content grows/shrinks toward the bottom-leading.
BottomLeading — Pin the bottom-leading corner; content grows/shrinks toward the top-trailing.
BottomTrailing — Pin the bottom-trailing corner; content grows/shrinks toward the top-leading.

`pub struct Scale`

Wraps a child widget and animates a uniform 2D visual scale on its subtree when an external Prop<bool> toggles between visible and hidden.

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

Methods

`pub fn new(visible: impl Into<Prop<bool>>) -> Self`

Create a scale wrapper bound to visible; accepts a static bool or a reactive Signal<bool>. Defaults: visual-only (no layout reflow), Center origin, MotionTokens::duration_normal + easing_standard.

`pub fn reflow(mut self, reflow: bool) -> Self`

When true, the wrapper's reported size shrinks with progress (siblings reflow). Pair with .origin(ScaleOrigin::TopLeading) for the "card removal" pattern. Default: false (visual-only).

`pub fn origin(mut self, origin: ScaleOrigin) -> Self`

Pivot point for the scale matrix. Default Center for visual- only mode; consider TopLeading when reflow=true.

`pub fn duration(mut self, duration: Duration) -> Self`

Override the tween duration. Default: MotionTokens::duration_normal.

`pub fn easing(mut self, easing: Easing) -> Self`

Override the easing. Default: MotionTokens::easing_standard.

Inline child widget (deferred insertion).

`pub fn child_id(mut self, id: WidgetId) -> Self`

Pre-registered child by WidgetId.

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