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use crate::internal::InternalLower;
use crate::lowering::{InternalIrBuilder, InternalLoweringCx};
use crate::ui::Widget;
use fission_ir::{
op::{LayoutOp, Op},
WidgetId,
};
use serde::{Deserialize, Serialize};
/// Absolutely positions a child within a [`ZStack`](super::ZStack).
///
/// Specify one or more edge offsets (`left`, `top`, `right`, `bottom`) and
/// optional explicit `width`/`height`. Omitting both horizontal offsets (or
/// both vertical offsets) leaves the child unconstrained on that axis.
///
/// # Example
///
/// ```rust,ignore
/// // Pin a badge to the top-right corner
/// Positioned {
/// top: Some(8.0),
/// right: Some(8.0),
/// child: Some(badge_widget),
/// ..Default::default()
/// }
/// ```
#[derive(Debug, Default, Clone, Serialize, Deserialize)]
pub struct Positioned {
/// Explicit node identity.
pub id: Option<WidgetId>,
/// Distance from the left edge of the parent.
pub left: Option<f32>,
/// Distance from the top edge of the parent.
pub top: Option<f32>,
/// Distance from the right edge of the parent.
pub right: Option<f32>,
/// Distance from the bottom edge of the parent.
pub bottom: Option<f32>,
/// Explicit width override.
pub width: Option<f32>,
/// Explicit height override.
pub height: Option<f32>,
/// The child widget to position.
pub child: Option<Widget>,
}
impl Positioned {}
impl InternalLower for Positioned {
fn lower(&self, cx: &mut InternalLoweringCx) -> WidgetId {
let id = self.id.map(Into::into).unwrap_or_else(|| cx.next_node_id());
cx.push_scope(id);
let child_id = if let Some(child) = &self.child {
Some(child.lower(cx))
} else {
None
};
let mut builder = InternalIrBuilder::new(
id,
Op::Layout(LayoutOp::Positioned {
left: self.left,
top: self.top,
right: self.right,
bottom: self.bottom,
width: self.width,
height: self.height,
}),
);
if let Some(cid) = child_id {
builder.add_child(cid);
}
cx.pop_scope();
builder.build(cx)
}
}