use refineable::Refineable as _;
use crate::{
App, Bounds, Element, ElementId, GlobalElementId, InspectorElementId, IntoElement, Pixels,
Style, StyleRefinement, Styled, Window,
};
pub fn canvas<T>(
prepaint: impl 'static + FnOnce(Bounds<Pixels>, &mut Window, &mut App) -> T,
paint: impl 'static + FnOnce(Bounds<Pixels>, T, &mut Window, &mut App),
) -> Canvas<T> {
Canvas {
prepaint: Some(Box::new(prepaint)),
paint: Some(Box::new(paint)),
style: StyleRefinement::default(),
}
}
pub struct Canvas<T> {
prepaint: Option<Box<dyn FnOnce(Bounds<Pixels>, &mut Window, &mut App) -> T>>,
paint: Option<Box<dyn FnOnce(Bounds<Pixels>, T, &mut Window, &mut App)>>,
style: StyleRefinement,
}
impl<T: 'static> IntoElement for Canvas<T> {
type Element = Self;
fn into_element(self) -> Self::Element {
self
}
}
impl<T: 'static> Element for Canvas<T> {
type RequestLayoutState = Style;
type PrepaintState = Option<T>;
fn id(&self) -> Option<ElementId> {
None
}
fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
None
}
fn request_layout(
&mut self,
_id: Option<&GlobalElementId>,
_inspector_id: Option<&InspectorElementId>,
window: &mut Window,
cx: &mut App,
) -> (crate::LayoutId, Self::RequestLayoutState) {
let mut style = Style::default();
style.refine(&self.style);
let layout_id = window.request_layout(style.clone(), [], cx);
(layout_id, style)
}
fn prepaint(
&mut self,
_id: Option<&GlobalElementId>,
_inspector_id: Option<&InspectorElementId>,
bounds: Bounds<Pixels>,
_request_layout: &mut Style,
window: &mut Window,
cx: &mut App,
) -> Option<T> {
Some(self.prepaint.take().unwrap()(bounds, window, cx))
}
fn paint(
&mut self,
_id: Option<&GlobalElementId>,
_inspector_id: Option<&InspectorElementId>,
bounds: Bounds<Pixels>,
style: &mut Style,
prepaint: &mut Self::PrepaintState,
window: &mut Window,
cx: &mut App,
) {
let prepaint = prepaint.take().unwrap();
style.paint(bounds, window, cx, |window, cx| {
(self.paint.take().unwrap())(bounds, prepaint, window, cx)
});
}
}
impl<T> Styled for Canvas<T> {
fn style(&mut self) -> &mut crate::StyleRefinement {
&mut self.style
}
}