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Simplify uniform list scrolling logic

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This commit is contained in:
Kirill Bulatov 2024-01-10 13:44:08 +02:00
parent f57ff1c660
commit c197ea49ca
2 changed files with 67 additions and 121 deletions
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76
crates/gpui/src/elements/uniform_list.rs
View file

@ -1,7 +1,7 @@
use crate::{
point, px, size, AnyElement, AvailableSpace, BorrowWindow, Bounds, ContentMask, Element,
ElementId, InteractiveElement, InteractiveElementState, Interactivity, IntoElement, LayoutId,
Pixels, Point, Render, Size, StyleRefinement, Styled, View, ViewContext, WindowContext,
Pixels, Render, Size, StyleRefinement, Styled, View, ViewContext, WindowContext,
};
use smallvec::SmallVec;
use std::{cell::RefCell, cmp, ops::Range, rc::Rc};
@ -65,48 +65,18 @@ pub struct UniformList {
#[derive(Clone, Default)]
pub struct UniformListScrollHandle {
state: Rc<RefCell<Option<ScrollHandleState>>>,
deferred_scroll_to_item: Option<usize>,
}
#[derive(Clone, Debug)]
struct ScrollHandleState {
item_height: Pixels,
list_height: Pixels,
scroll_offset: Rc<RefCell<Point<Pixels>>>,
deferred_scroll_to_item: Rc<RefCell<Option<usize>>>,
}
impl UniformListScrollHandle {
pub fn new() -> Self {
Self {
state: Rc::new(RefCell::new(None)),
deferred_scroll_to_item: None,
deferred_scroll_to_item: Rc::new(RefCell::new(None)),
}
}
pub fn scroll_to_item(&mut self, ix: usize) {
if let Some(state) = &*self.state.borrow() {
let mut scroll_offset = state.scroll_offset.borrow_mut();
let item_top = state.item_height * ix;
let item_bottom = item_top + state.item_height;
let scroll_top = -scroll_offset.y;
if item_top < scroll_top {
scroll_offset.y = -item_top;
} else if item_bottom > scroll_top + state.list_height {
scroll_offset.y = -(item_bottom - state.list_height);
}
self.deferred_scroll_to_item = None;
} else {
self.deferred_scroll_to_item = Some(ix);
}
}
pub fn scroll_top(&mut self) -> Pixels {
if let Some(state) = &*self.state.borrow() {
-state.scroll_offset.borrow().y
} else {
Pixels::ZERO
}
self.deferred_scroll_to_item.replace(Some(ix));
}
}
@ -199,18 +169,14 @@ impl Element for UniformList {
let shared_scroll_offset = element_state
.interactive
.scroll_offset
.get_or_insert_with(|| {
if let Some(scroll_handle) = self.scroll_handle.as_ref() {
if let Some(scroll_handle) = scroll_handle.state.borrow().as_ref() {
return scroll_handle.scroll_offset.clone();
}
}
Rc::default()
})
.get_or_insert_with(|| Rc::default())
.clone();
let item_height = self.measure_item(Some(padded_bounds.size.width), cx).height;
let shared_scroll_to_item = self
.scroll_handle
.as_mut()
.and_then(|handle| handle.deferred_scroll_to_item.take());
self.interactivity.paint(
bounds,
@ -237,20 +203,18 @@ impl Element for UniformList {
scroll_offset.y = min_scroll_offset;
}
if let Some(scroll_handle) = self.scroll_handle.as_mut() {
scroll_handle.state.borrow_mut().replace(ScrollHandleState {
item_height,
list_height: padded_bounds.size.height,
scroll_offset: shared_scroll_offset.clone(),
});
if let Some(scroll_handle) = self.scroll_handle.as_mut() {
if scroll_handle.state.borrow().is_some() {
if let Some(ix) = scroll_handle.deferred_scroll_to_item.take() {
scroll_handle.scroll_to_item(ix);
scroll_offset = *shared_scroll_offset.borrow();
}
}
if let Some(ix) = shared_scroll_to_item {
let list_height = padded_bounds.size.height;
let mut updated_scroll_offset = shared_scroll_offset.borrow_mut();
let item_top = item_height * ix;
let item_bottom = item_top + item_height;
let scroll_top = -updated_scroll_offset.y;
if item_top < scroll_top {
updated_scroll_offset.y = -item_top;
} else if item_bottom > scroll_top + list_height {
updated_scroll_offset.y = -(item_bottom - list_height);
}
scroll_offset = *updated_scroll_offset;
}
let first_visible_element_ix =