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crates/strato-ui-core/src/elements/clipped_scrollable_test.rs

StratoSDK / crates / strato-ui-core / src / elements / clipped_scrollable_test.rs

1	use std::collections::HashSet;
2
3	use pathfinder_geometry::vector::vec2f;
4
5	use crate::{
6	elements::{Axis, ConstrainedBox, Empty, Flex, ParentElement, SavePosition, Stack},
7	platform::WindowStyle,
8	units::IntoPixels,
9	App, Element, Entity, Presenter, TypedActionView, WindowInvalidation,
10	};
11
12	use super::{ClippedScrollStateHandle, ClippedScrollable, ScrollTarget, ScrollToPositionMode};
13
14	macro_rules! assert_float_eq {
15	($lhs:expr, $rhs:expr) => {{
16	let lhs = $lhs;
17	let rhs = $rhs;
18	assert!(
19	(lhs - rhs).abs() < f32::EPSILON,
20	"{} ({}) != {} ({})",
21	lhs,
22	stringify!($lhs),
23	rhs,
24	stringify!($rhs)
25	);
26	}};
27	}
28
29	#[derive(Default)]
30	struct View {
31	scroll_handle: ClippedScrollStateHandle,
32	}
33
34	impl Entity for View {
35	type Event = ();
36	}
37
38	impl crate::core::View for View {
39	fn ui_name() -> &'static str {
40	"View"
41	}
42
43	fn render(&self, _: &crate::AppContext) -> Box<dyn crate::Element> {
44	let mut children = vec![];
45	for i in 0..10 {
46	children.push(
47	SavePosition::new(
48	ConstrainedBox::new(Empty::new().finish())
49	.with_height(20.)
50	.with_width(100.)
51	.finish(),
52	&format!("child_{i}"),
53	)
54	.finish(),
55	);
56	}
57
58	let mut stack = Stack::new();
59	stack.add_child(
60	ClippedScrollable::new(
61	Axis::Vertical,
62	Flex::column().with_children(children).finish(),
63	self.scroll_handle.clone(),
64	)
65	.finish(),
66	);
67	stack.finish()
68	}
69	}
70
71	impl TypedActionView for View {
72	type Action = ();
73	}
74
75	#[test]
76	fn test_scroll_to_position() {
77	App::test((), \|mut app\| async move {
78	let app = &mut app;
79	let (window_id, view) = app.add_window(WindowStyle::NotStealFocus, \|_\| View::default());
80
81	let mut presenter = Presenter::new(window_id);
82
83	let mut updated = HashSet::new();
84	updated.insert(app.root_view_id(window_id).unwrap());
85	let invalidation = WindowInvalidation {
86	updated,
87	..Default::default()
88	};
89
90	let scroll_state = view.read(app, \|view, _\| view.scroll_handle.clone());
91	let window_size = vec2f(100., 100.);
92	let scale_factor = 1.;
93
94	app.update(move \|ctx\| {
95	presenter.invalidate(invalidation.clone(), ctx);
96	// The `ClippedScrollable` has 10 elements in total, each with a height of 20.
97	// The window height is 100 so, with a scroll top of 0, the first 5 elements should be
98	// in view.
99	presenter.build_scene(window_size, scale_factor, None, ctx);
100
101	// An element fully below the scrollable area should be the last item in view
102	// after we scroll to it.
103	scroll_state.scroll_to_position(ScrollTarget {
104	position_id: "child_6".to_string(),
105	mode: ScrollToPositionMode::FullyIntoView,
106	});
107	presenter.invalidate(invalidation.clone(), ctx);
108	presenter.build_scene(window_size, scale_factor, None, ctx);
109	assert_float_eq!(scroll_state.scroll_start().as_f32(), 40.);
110
111	// An element fully above the scrollable area should be the first item in view after
112	// it's scrolled to.
113	scroll_state.scroll_to_position(ScrollTarget {
114	position_id: "child_1".to_string(),
115	mode: ScrollToPositionMode::FullyIntoView,
116	});
117	presenter.invalidate(invalidation.clone(), ctx);
118	presenter.build_scene(window_size, scale_factor, None, ctx);
119	assert_float_eq!(scroll_state.scroll_start().as_f32(), 20.);
120
121	// An element fully within the viewport should no-op.
122	scroll_state.scroll_to_position(ScrollTarget {
123	position_id: "child_3".to_string(),
124	mode: ScrollToPositionMode::FullyIntoView,
125	});
126	presenter.invalidate(invalidation.clone(), ctx);
127	presenter.build_scene(window_size, scale_factor, None, ctx);
128	assert_float_eq!(scroll_state.scroll_start().as_f32(), 20.);
129
130	// An element that is partially above the viewport should be scrolled fully within the viewport.
131	// First, make the scroll top 1.0 pixels. We need to call build scene after this so the
132	// position cache is updated appropriately.
133	scroll_state.clipped_scroll_data.lock().scroll_start_px = (1_f32).into_pixels();
134	presenter.invalidate(invalidation.clone(), ctx);
135	presenter.build_scene(window_size, scale_factor, None, ctx);
136
137	// Now we can invoke the scroll to position API and verify the correct result.
138	scroll_state.scroll_to_position(ScrollTarget {
139	position_id: "child_0".to_string(),
140	mode: ScrollToPositionMode::FullyIntoView,
141	});
142	presenter.invalidate(invalidation.clone(), ctx);
143	presenter.build_scene(window_size, scale_factor, None, ctx);
144	assert_float_eq!(scroll_state.scroll_start().as_f32(), 0.);
145
146	// An element that is partially below the viewport should be scrolled fully within the viewport.
147	// First, make the scroll top 1.0 pixels. We need to call build scene after this so the
148	// position cache is updated appropriately.
149	scroll_state.clipped_scroll_data.lock().scroll_start_px = (1_f32).into_pixels();
150	presenter.invalidate(invalidation.clone(), ctx);
151	presenter.build_scene(window_size, scale_factor, None, ctx);
152
153	// Now we can invoke the scroll to position API and verify the correct result.
154	scroll_state.scroll_to_position(ScrollTarget {
155	position_id: "child_5".to_string(),
156	mode: ScrollToPositionMode::FullyIntoView,
157	});
158	presenter.invalidate(invalidation.clone(), ctx);
159	presenter.build_scene(window_size, scale_factor, None, ctx);
160	assert_float_eq!(scroll_state.scroll_start().as_f32(), 20.);
161	});
162	});
163	}
164

Seregon/StratoSDK