ZIm/crates/gpui/playground/src/hoverable.rs
Nathan Sobo 5996b6b46b Use RefinementCascade to compose pressability and hoverability
Co-Authored-By: Conrad Irwin <conrad@zed.dev>
2023-08-23 12:18:12 -06:00

78 lines
2.1 KiB
Rust

use crate::{
element::{Element, Layout},
layout_context::LayoutContext,
paint_context::PaintContext,
style::{Style, StyleHelpers, Styleable},
};
use anyhow::Result;
use gpui::platform::MouseMovedEvent;
use refineable::{CascadeSlot, Refineable, RefinementCascade};
use std::{cell::Cell, rc::Rc};
pub struct Hoverable<E: Styleable> {
hovered: Rc<Cell<bool>>,
cascade_slot: CascadeSlot,
hovered_style: <E::Style as Refineable>::Refinement,
child: E,
}
pub fn hoverable<E: Styleable>(mut child: E) -> Hoverable<E> {
Hoverable {
hovered: Rc::new(Cell::new(false)),
cascade_slot: child.style_cascade().reserve(),
hovered_style: Default::default(),
child,
}
}
impl<E: Styleable> Styleable for Hoverable<E> {
type Style = E::Style;
fn style_cascade(&mut self) -> &mut RefinementCascade<Self::Style> {
self.child.style_cascade()
}
fn declared_style(&mut self) -> &mut <Self::Style as Refineable>::Refinement {
&mut self.hovered_style
}
}
impl<V: 'static, E: Element<V> + Styleable> Element<V> for Hoverable<E> {
type Layout = E::Layout;
fn layout(&mut self, view: &mut V, cx: &mut LayoutContext<V>) -> Result<Layout<V, Self::Layout>>
where
Self: Sized,
{
self.child.layout(view, cx)
}
fn paint(
&mut self,
view: &mut V,
layout: &mut Layout<V, Self::Layout>,
cx: &mut PaintContext<V>,
) where
Self: Sized,
{
let bounds = layout.bounds(cx);
let order = layout.order(cx);
self.hovered.set(bounds.contains_point(cx.mouse_position()));
let slot = self.cascade_slot;
let style = self.hovered.get().then_some(self.hovered_style.clone());
self.style_cascade().set(slot, style);
let hovered = self.hovered.clone();
cx.on_event(order, move |view, event: &MouseMovedEvent, cx| {
if bounds.contains_point(event.position) != hovered.get() {
cx.repaint();
}
});
self.child.paint(view, layout, cx);
}
}
impl<E: Styleable<Style = Style>> StyleHelpers for Hoverable<E> {}