116 lines
3.1 KiB
Rust
116 lines
3.1 KiB
Rust
use crate::cache::{self, Cached};
|
|
use crate::core::Size;
|
|
use crate::geometry::{self, Frame};
|
|
|
|
pub use cache::Group;
|
|
|
|
/// A simple cache that stores generated geometry to avoid recomputation.
|
|
///
|
|
/// A [`Cache`] will not redraw its geometry unless the dimensions of its layer
|
|
/// change or it is explicitly cleared.
|
|
pub struct Cache<Renderer>
|
|
where
|
|
Renderer: geometry::Renderer,
|
|
{
|
|
raw: crate::Cache<Data<<Renderer::Geometry as Cached>::Cache>>,
|
|
}
|
|
|
|
#[derive(Debug, Clone)]
|
|
struct Data<T> {
|
|
bounds: Size,
|
|
geometry: T,
|
|
}
|
|
|
|
impl<Renderer> Cache<Renderer>
|
|
where
|
|
Renderer: geometry::Renderer,
|
|
{
|
|
/// Creates a new empty [`Cache`].
|
|
pub fn new() -> Self {
|
|
Cache {
|
|
raw: cache::Cache::new(),
|
|
}
|
|
}
|
|
|
|
/// Creates a new empty [`Cache`] with the given [`Group`].
|
|
///
|
|
/// Caches within the same group may reuse internal rendering storage.
|
|
///
|
|
/// You should generally group caches that are likely to change
|
|
/// together.
|
|
pub fn with_group(group: Group) -> Self {
|
|
Cache {
|
|
raw: crate::Cache::with_group(group),
|
|
}
|
|
}
|
|
|
|
/// Clears the [`Cache`], forcing a redraw the next time it is used.
|
|
pub fn clear(&self) {
|
|
self.raw.clear();
|
|
}
|
|
|
|
/// Draws geometry using the provided closure and stores it in the
|
|
/// [`Cache`].
|
|
///
|
|
/// The closure will only be called when
|
|
/// - the bounds have changed since the previous draw call.
|
|
/// - the [`Cache`] is empty or has been explicitly cleared.
|
|
///
|
|
/// Otherwise, the previously stored geometry will be returned. The
|
|
/// [`Cache`] is not cleared in this case. In other words, it will keep
|
|
/// returning the stored geometry if needed.
|
|
pub fn draw(
|
|
&self,
|
|
renderer: &Renderer,
|
|
bounds: Size,
|
|
draw_fn: impl FnOnce(&mut Frame<Renderer>),
|
|
) -> Renderer::Geometry {
|
|
use std::ops::Deref;
|
|
|
|
let state = self.raw.state();
|
|
|
|
let previous = match state.borrow().deref() {
|
|
cache::State::Empty { previous } => {
|
|
previous.as_ref().map(|data| data.geometry.clone())
|
|
}
|
|
cache::State::Filled { current } => {
|
|
if current.bounds == bounds {
|
|
return Cached::load(¤t.geometry);
|
|
}
|
|
|
|
Some(current.geometry.clone())
|
|
}
|
|
};
|
|
|
|
let mut frame = Frame::new(renderer, bounds);
|
|
draw_fn(&mut frame);
|
|
|
|
let geometry = frame.into_geometry().cache(self.raw.group(), previous);
|
|
let result = Cached::load(&geometry);
|
|
|
|
*state.borrow_mut() = cache::State::Filled {
|
|
current: Data { bounds, geometry },
|
|
};
|
|
|
|
result
|
|
}
|
|
}
|
|
|
|
impl<Renderer> std::fmt::Debug for Cache<Renderer>
|
|
where
|
|
Renderer: geometry::Renderer,
|
|
<Renderer::Geometry as Cached>::Cache: std::fmt::Debug,
|
|
{
|
|
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
|
write!(f, "{:?}", &self.raw)
|
|
}
|
|
}
|
|
|
|
impl<Renderer> Default for Cache<Renderer>
|
|
where
|
|
Renderer: geometry::Renderer,
|
|
{
|
|
fn default() -> Self {
|
|
Self::new()
|
|
}
|
|
}
|