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MinSize

retroglyph_ui::widget

Trait MinSize 

Source 
pub trait MinSize {
    // Required method
    fn min_size(&self, density: Density) -> Size;
}
Expand description

A widget that can report the smallest size its content and Density allow, before ever being rendered.

This is a different question from Measure::height_for: height_for answers “how tall are you, given this width” (content wrapped into a fixed width); min_size answers “how small can you be at all” (a floor driven by both content and the Density a caller is targeting). Conflating the two into one trait/method would force every Measure impl to also take a Density it doesn’t need, and every MinSize impl to accept a width it can’t use to answer “how small can you get”. Kept separate on purpose; a widget can implement either, both, or neither.

Interactive widgets (Button, Tabs, Scrollbar, TextInput) are the intended implementors: Density::min_target_size exists specifically so a caller sizing a clickable/tappable control doesn’t have to invent its own touch-target floor, and min_size is how a widget applies that floor to its own content.

§Examples

use retroglyph_core::grid::Size;
use retroglyph_ui::interact::Density;
use retroglyph_ui::widget::MinSize;

struct FixedSize(Size);

impl MinSize for FixedSize {
    fn min_size(&self, density: Density) -> Size {
        self.0.max(density.min_target_size())
    }
}

let small = FixedSize(Size::new(1, 1));
assert_eq!(small.min_size(Density::Mouse), Density::Mouse.min_target_size());

Required Methods§

Source

fn min_size(&self, density: Density) -> Size

The smallest size, in cells, this widget can be drawn at without clipping its content or falling below density’s minimum interactive target size.

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§