Constrain offered boxes with independent widget size bounds

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iris-ai committed 2026-09-20 19:47:32 -04:00
1 parent 4cb6f6882a
commit 2ac0843cb2
18 files changed
+554 -379

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-68
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@@ -1,68 +0,0 @@
use crate::prelude::*;
/// Asks its child in the shorter of a cap and the box this widget was given,
/// and answers what the child used, held to the same cap.
///
/// A cap on the box is a widget rather than a [`SizeRule`] because a box is
/// whoever asked's to decide: a rule that read the box it was given would be
/// decided again by every path that hands a widget one, including the ones
/// that re-place a drawing without asking it anything, and the decision would
/// then depend on which path arrived last. A widget is drawn again whenever
/// its own box changes, so the comparison is made where the answer can be
/// kept -- `longer_than` narrows the windows this drawing holds for, and
/// `holds` says the box lengths.
///
/// The box is what a text wraps at and what a scroll takes its viewport from,
/// which is why capping the answer alone is not the same thing.
pub struct MaxSize {
pub inner: StrongWidget,
pub x: Option<Len>,
pub y: Option<Len>,
}
impl MaxSize {
fn max(&self, axis: Axis) -> Option<Len> {
match axis {
Axis::X => self.x,
Axis::Y => self.y,
}
}
}
impl Widget for MaxSize {
fn size_request(&self, requests: &mut SizeRequests, axis: Axis) -> Option<RequestedLen> {
let inner = requests.widget(&self.inner, axis)?;
Some(match self.max(axis) {
Some(max) => requests.min(inner, max.into()),
None => inner,
})
}
fn draw(&mut self, painter: &mut Painter) -> Size {
let align = painter.alignment();
let mut region = UiRegion::FULL;
for axis in Axis::BOTH {
let Some(max) = self.max(axis) else {
continue;
};
let own = painter.region_len(axis);
if painter.longer_than(own, max, axis) {
region[axis] = max.align(align[axis]);
}
}
let mut size = painter.widget_at(&self.inner, region).size();
for axis in Axis::BOTH {
// The child may draw past the box it was given -- a text too tall
// for it -- and the cap is a promise about the length as well. A
// share passes through: it is a length only to whoever divides
// one, and that is this widget's parent rather than this widget,
// which has already given the share the box the cap allows.
if let Some(max) = self.max(axis)
&& painter.longer_than(size[axis].without_leftover(), max, axis)
{
size[axis] = max.into();
}
}
size
}
}
-2
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@@ -1,5 +1,4 @@
mod layer;
mod max_size;
mod offset;
mod pad;
mod scroll;
@@ -7,7 +6,6 @@ mod span;
mod stack;
pub use layer::*;
pub use max_size::*;
pub use offset::*;
pub use pad::*;
pub use scroll::*;