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use crate::{input::mouse, Column, Element, Event, Layout, MouseCursor, Point};
use std::hash::Hasher;
use stretch::result;
pub struct Runtime {
cache: Cache,
events: Vec<Event>,
cursor_position: Point,
}
impl Runtime {
pub fn new() -> Runtime {
// We use this as a placeholder to initialize the cache.
// This way, we can avoid the overhead of using an `Option`
// in `compute`.
let root: Element<'_, (), ()> = Column::new().into();
let hasher = &mut crate::Hasher::default();
root.hash(hasher);
Runtime {
cache: Cache {
hash: hasher.finish(),
layout: root.compute_layout(&()),
},
events: Vec::new(),
cursor_position: Point::new(0.0, 0.0),
}
}
pub fn on_event(&mut self, event: Event) {
match event {
Event::Mouse(mouse::Event::CursorMoved { x, y }) => {
self.cursor_position = Point::new(x, y);
}
_ => {}
}
self.events.push(event);
}
pub fn compute<'a, Message, Renderer>(
&'a mut self,
root: Element<'a, Message, Renderer>,
renderer: &Renderer,
) -> Interface<'a, Message, Renderer> {
let hasher = &mut crate::Hasher::default();
root.hash(hasher);
let hash = hasher.finish();
if hash != self.cache.hash {
self.cache = Cache {
hash,
layout: root.compute_layout(renderer),
};
}
Interface {
root,
layout: &self.cache.layout,
events: &mut self.events,
cursor_position: self.cursor_position,
}
}
}
struct Cache {
hash: u64,
layout: result::Layout,
}
pub struct Interface<'a, Message, Renderer> {
root: Element<'a, Message, Renderer>,
layout: &'a result::Layout,
events: &'a mut Vec<Event>,
cursor_position: Point,
}
impl<'a, Message, Renderer> Interface<'a, Message, Renderer> {
pub fn update(&mut self) -> Vec<Message> {
let mut messages = Vec::new();
for event in self.events.drain(..) {
self.root.widget.on_event(
event,
Layout::new(&self.layout),
self.cursor_position,
&mut messages,
);
}
messages
}
pub fn draw(
&self,
renderer: &mut Renderer,
cursor_position: Point,
) -> MouseCursor {
let cursor = self.root.widget.draw(
renderer,
Layout::new(self.layout),
cursor_position,
);
cursor
}
}
|
