6a7761e620
The new `ElementContext` was originally introduced to ensure the element APIs could only be used inside of elements. Unfortunately, there were many places where some of those APIs needed to be used, so `WindowContext::with_element_context` was introduced, which defeated the original safety purposes of having a specific context for elements. This pull request merges `ElementContext` into `WindowContext` and adds (debug) runtime checks to APIs that can only be used during certain phases of element drawing. Release Notes: - N/A --------- Co-authored-by: Nathan Sobo <nathan@zed.dev>
75 lines
2.1 KiB
Rust
75 lines
2.1 KiB
Rust
use refineable::Refineable as _;
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use crate::{Bounds, Element, IntoElement, Pixels, Style, StyleRefinement, Styled, WindowContext};
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/// Construct a canvas element with the given paint callback.
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/// Useful for adding short term custom drawing to a view.
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pub fn canvas<T>(
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prepaint: impl 'static + FnOnce(Bounds<Pixels>, &mut WindowContext) -> T,
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paint: impl 'static + FnOnce(Bounds<Pixels>, T, &mut WindowContext),
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) -> Canvas<T> {
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Canvas {
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prepaint: Some(Box::new(prepaint)),
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paint: Some(Box::new(paint)),
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style: StyleRefinement::default(),
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}
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}
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/// A canvas element, meant for accessing the low level paint API without defining a whole
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/// custom element
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pub struct Canvas<T> {
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prepaint: Option<Box<dyn FnOnce(Bounds<Pixels>, &mut WindowContext) -> T>>,
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paint: Option<Box<dyn FnOnce(Bounds<Pixels>, T, &mut WindowContext)>>,
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style: StyleRefinement,
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}
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impl<T: 'static> IntoElement for Canvas<T> {
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type Element = Self;
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fn into_element(self) -> Self::Element {
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self
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}
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}
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impl<T: 'static> Element for Canvas<T> {
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type RequestLayoutState = Style;
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type PrepaintState = Option<T>;
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fn request_layout(
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&mut self,
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cx: &mut WindowContext,
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) -> (crate::LayoutId, Self::RequestLayoutState) {
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let mut style = Style::default();
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style.refine(&self.style);
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let layout_id = cx.request_layout(&style, []);
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(layout_id, style)
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}
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fn prepaint(
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&mut self,
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bounds: Bounds<Pixels>,
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_request_layout: &mut Style,
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cx: &mut WindowContext,
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) -> Option<T> {
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Some(self.prepaint.take().unwrap()(bounds, cx))
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}
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fn paint(
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&mut self,
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bounds: Bounds<Pixels>,
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style: &mut Style,
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prepaint: &mut Self::PrepaintState,
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cx: &mut WindowContext,
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) {
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let prepaint = prepaint.take().unwrap();
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style.paint(bounds, cx, |cx| {
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(self.paint.take().unwrap())(bounds, prepaint, cx)
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});
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}
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}
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impl<T> Styled for Canvas<T> {
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fn style(&mut self) -> &mut crate::StyleRefinement {
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&mut self.style
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}
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}
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