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use crate::{
canvas::{Frame, Geometry},
Primitive,
};
use iced_native::Size;
use std::{cell::RefCell, sync::Arc};
enum State {
Empty,
Filled {
bounds: Size,
primitive: Arc<Primitive>,
},
}
impl Default for State {
fn default() -> Self {
State::Empty
}
}
#[derive(Debug, Default)]
pub struct Cache {
state: RefCell<State>,
}
impl Cache {
pub fn new() -> Self {
Cache {
state: Default::default(),
}
}
pub fn clear(&mut self) {
*self.state.borrow_mut() = State::Empty;
}
pub fn draw(&self, bounds: Size, draw_fn: impl Fn(&mut Frame)) -> Geometry {
use std::ops::Deref;
if let State::Filled {
bounds: cached_bounds,
primitive,
} = self.state.borrow().deref()
{
if *cached_bounds == bounds {
return Geometry::from_primitive(Primitive::Cached {
cache: primitive.clone(),
});
}
}
let mut frame = Frame::new(bounds);
draw_fn(&mut frame);
let primitive = {
let geometry = frame.into_geometry();
Arc::new(geometry.into_primitive())
};
*self.state.borrow_mut() = State::Filled {
bounds,
primitive: primitive.clone(),
};
Geometry::from_primitive(Primitive::Cached { cache: primitive })
}
}
impl std::fmt::Debug for State {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
State::Empty => write!(f, "Empty"),
State::Filled { primitive, bounds } => f
.debug_struct("Filled")
.field("primitive", primitive)
.field("bounds", bounds)
.finish(),
}
}
}