TouchTarget

TouchTarget — the last resort of the three hit-targeting mechanisms: the one that actually moves things.

Builder methods at a glance

size, reserve_space, child, child_id

API reference

📖 Full rustdoc API for this module

pub struct TouchTarget

Give an undersized control a conforming touch target, growing the layout around it when nothing cheaper will do — and only at TargetDensity::Touch.

When you need this, and when you do not

Teksilo has three ways to make a target reachable, and they are ordered by how much they disturb:

1. Widget::hit_outset — a thin grip claims the space around it. Hit-only; nothing moves. This is what a splitter gutter or a column resize strip uses.
2. The miss-only slop pass — an isolated small control catches a near miss. Hit-only; nothing moves. This is what a radio dot or a chart mark uses.
3. TouchTarget — this. The control genuinely needs room, because the thing beside it is also a target and there is no space to borrow. It changes layout, so siblings reflow.

Reach for (3) only when (1) and (2) cannot work: when a control sits in a tight row of other controls, so widening its hit area would take presses from its neighbours rather than from empty space. Everything else the density sweep already handles by projecting the recipes.

Why Touch only

At Compact and Comfortable this wrapper is the identity: it reports its child's own response, unchanged, and adds no hit outset. Compact is the density every existing layout was designed at and every layout golden was recorded at, and Comfortable is served by the recipes' own density projection, which raises a control's own dimensions rather than padding around it. Touch is the ladder where a 24 dp control still falls 20 dp short of the target and no recipe can close the gap from inside.

// A 16 dp close affordance in a dense tab strip: at Touch it is given a
// 44 dp slot and centred in it; at Compact nothing changes at all.
TouchTarget::new().child(close_button)

reserve_space

• reserve_space(true) (the default) — the slot reports at least size on both axes and centres the child in it. Siblings reflow.
• reserve_space(false) — the slot reports the child's own size and declares a Widget::hit_outset that brings the hit area up to size instead. Nothing moves; the target overlaps whatever is beside it. Use it when the row has slack in one direction but you cannot spend it.

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

Methods

pub fn new() -> Self

A new wrapper at the density's own target_size. Attach content with child or child_id.

pub fn size(mut self, dp: f32) -> Self

Override the target size, in dp. Defaults to the density's InputTokens::target_size (44 dp at Touch).

pub fn reserve_space(mut self, reserve: bool) -> Self

Whether the slot takes the room it needs (true, the default) or widens only the hit area (false). See the type docs.

pub fn child(mut self, widget: impl Widget + 'static) -> Self

Wrap an inline widget.

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

Wrap a pre-registered widget by id.