nav-scrollabe: detect size to determine if needs scrolling, msg when ready

[?]

Jun 28, 2025, 9:47 AM

WIFVLV376GIMVTGVXBFWIPU7FR5O3SGIQ343KIJEBWB6UURTJZJQC

Dependencies

[2] 6YZAVBWU Initial commit
[3] 3SYSJKYL add app icon
[4] 23SFYK4Q big view refactor into a new crate
[5] SGHF5QCV cargo update
[6] WW36JYLR add iced_nav_scrollable widget crate
[7] KLR5FRIB add fs state read/write of repos
[8] IQDCHWCP load a pijul repo
[9] 6SW7UVSH update iced version

Change contents

edit in iced_nav_scrollable/src/lib.rs at line 6

[6.309]

[6.309]

use iced_futures::MaybeSend;
edit in iced_nav_scrollable/src/lib.rs at line 11

[6.378]→[6.378:457](∅→∅)

pub offsets_ready: bool,
pub offsets: Vec<f32>,
pub y_offset: f32,
replacement in iced_nav_scrollable/src/lib.rs at line 12

[6.485]→[6.485:533](∅→∅)

pub sections: IndexMap<container::Id, f32>,

[6.485]

[6.533]

pub height: f32,
pub offset: f32,
pub needs_scrolling: NeedsScrolling,
pub generation: usize,
pub section_heights: IndexMap<container::Id, f32>,
pub section_offsets: Vec<f32>,
pub pending_tasks: Option<usize>,
replacement in iced_nav_scrollable/src/lib.rs at line 24

[6.595]→[6.595:645](∅→∅)

GotHeight { id: container::Id, height: f32 },

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[6.645]

GotScrollableHeight {
height: f32,
generation: usize,
},
GotSectionHeight {
id: container::Id,
height: f32,
generation: usize,
},
edit in iced_nav_scrollable/src/lib.rs at line 36

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}

#[derive(Debug, Clone, Copy)]
pub enum NeedsScrolling {
Yes,
No,
replacement in iced_nav_scrollable/src/lib.rs at line 45

[6.787]→[6.787:861](∅→∅)

let (sections, tasks): (IndexMap<_, _>, Vec<_>) = (0..contents_count)

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[6.861]

let generation = 0;
let (section_heights, mut tasks): (IndexMap<_, _>, Vec<_>) = (0
..contents_count)
replacement in iced_nav_scrollable/src/lib.rs at line 54

[6.1017]→[6.1017:1115](∅→∅)

let task =
height_task(id.clone()).map(move |height| Msg::GotHeight {

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[6.1115]

let task = container_height_task(id.clone()).map(move |height| {
Msg::GotSectionHeight {
replacement in iced_nav_scrollable/src/lib.rs at line 58

[6.1185]→[6.1185:1205](∅→∅)

});

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generation,
}
});
edit in iced_nav_scrollable/src/lib.rs at line 66

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tasks
.push(scrollable_height_task(id.clone()).map(move |height| {
Msg::GotScrollableHeight { height, generation }
}));
// To be computed from sizes once tasks complete
let section_offsets = vec![0.0; section_heights.len()];
// 1 task to get the scrollable height
let pending_tasks = Some(contents_count + 1);
edit in iced_nav_scrollable/src/lib.rs at line 76

[6.1334]→[6.1334:1504](∅→∅)

offsets_ready: false,
// To be computed from sizes once tasks complete
offsets: vec![0.0; sections.len()],
y_offset: 0.0,
replacement in iced_nav_scrollable/src/lib.rs at line 77

[6.1520]→[6.1520:1542](∅→∅)

sections,

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[6.1542]

height: 0.0,
offset: 0.0,
needs_scrolling: NeedsScrolling::Yes,
generation,
section_heights,
section_offsets,
// 1 task to get the scrollable height
pending_tasks,
replacement in iced_nav_scrollable/src/lib.rs at line 94

[6.1687]→[6.1687:1751](∅→∅)

pub fn update(nav: &mut NavScrollable, msg: Msg) -> Task<Msg> {

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pub fn update<Message, MapFn, OnReady>(
nav: &mut NavScrollable,
msg: Msg,
map_msg: MapFn,
on_ready: OnReady,
) -> Task<Message>
where
Message: MaybeSend + 'static,
MapFn: Fn(Msg) -> Message + MaybeSend + 'static,
OnReady: Fn(NeedsScrolling) -> Message,
{
replacement in iced_nav_scrollable/src/lib.rs at line 108

[6.1832]→[6.1832:2110](∅→∅)

Task::batch(nav.sections.keys().map(|id| {
let id_clone = id.clone();
height_task(id.clone()).map(move |height| Msg::GotHeight {
id: id_clone.clone(),
height,
})
}))

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[6.2110]

let generation = nav.generation;
// 1 task to get the scrollable height
nav.pending_tasks = Some(nav.section_heights.len() + 1);
Task::batch(
nav.section_heights
.keys()
.map(|id| {
let id_clone = id.clone();
container_height_task(id.clone()).map(move |height| {
Msg::GotSectionHeight {
id: id_clone.clone(),
height,
generation,
}
})
})
.chain([scrollable_height_task(nav.id.clone()).map(
move |height| Msg::GotScrollableHeight {
height,
generation,
},
)]),
)
.map(map_msg)
}
Msg::GotScrollableHeight { height, generation } => {
if generation == nav.generation {
nav.height = height;

if let Some(offsets) = nav.pending_tasks.as_mut() {
*offsets -= 1;
update_offsets_if_ready(nav);
if nav.pending_tasks.is_none() {
return Task::done(on_ready(nav.needs_scrolling));
}
}
}
Task::none()
replacement in iced_nav_scrollable/src/lib.rs at line 148

[6.2120]→[6.2120:2240](∅→∅)

Msg::GotHeight { id, height } => {
reset_offsets(nav);
nav.sections.insert(id, height);

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Msg::GotSectionHeight {
id,
height,
generation,
} => {
if generation == nav.generation {
nav.section_heights.insert(id, height);

if let Some(offsets) = nav.pending_tasks.as_mut() {
*offsets -= 1;
update_offsets_if_ready(nav);
if nav.pending_tasks.is_none() {
return Task::done(on_ready(nav.needs_scrolling));
}
}
}
replacement in iced_nav_scrollable/src/lib.rs at line 167

[6.2312]→[6.2312:2369](∅→∅)

nav.y_offset = viewport.absolute_offset().y;

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nav.offset = viewport.absolute_offset().y;
replacement in iced_nav_scrollable/src/lib.rs at line 171

[6.2435]→[6.2435:2614](∅→∅)

update_offsets(nav);
if nav.offsets_ready {
if let Some(y) =
nav.offsets.iter().find(|offset| *offset > &nav.y_offset)

[6.2435]

[6.2614]

if nav.pending_tasks.is_none() {
if let Some(y) = nav
.section_offsets
.iter()
.find(|offset| *offset > &nav.offset)
replacement in iced_nav_scrollable/src/lib.rs at line 186

[6.2913]→[6.2913:2981](∅→∅)

update_offsets(nav);
if nav.offsets_ready {

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[6.2981]

if nav.pending_tasks.is_none() {
replacement in iced_nav_scrollable/src/lib.rs at line 188

[6.3018]→[6.3018:3047](∅→∅)

.offsets

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[6.3047]

.section_offsets
replacement in iced_nav_scrollable/src/lib.rs at line 191

[6.3102]→[6.3102:3162](∅→∅)

.find(|offset| *offset < &nav.y_offset)

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.find(|offset| *offset < &nav.offset)
replacement in iced_nav_scrollable/src/lib.rs at line 206

[6.3546]→[6.3546:3592](∅→∅)

pub fn view<'a, Message, Theme, Renderer, F>(

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[6.3592]

pub fn view<'a, Message, Theme, Renderer, MapFn>(
replacement in iced_nav_scrollable/src/lib.rs at line 210

[6.3724]→[6.3724:3740](∅→∅)

map_msg: F,

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map_msg: MapFn,
replacement in iced_nav_scrollable/src/lib.rs at line 216

[6.3909]→[6.3909:3941](∅→∅)

F: Fn(Msg) -> Message + 'a,

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MapFn: Fn(Msg) -> Message + 'a,
replacement in iced_nav_scrollable/src/lib.rs at line 218

[6.3943]→[6.3943:4211](∅→∅)

debug_assert_eq!(nav.sections.len(), children.len(), "The `NavScrollable` was most likely initialized with a count different from the number of actual children given to the the view function. Count is {}, but got {} children", nav.sections.len(), children.len());

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debug_assert_eq!(nav.section_heights.len(), children.len(), "The `NavScrollable` was most likely initialized with a count different from the number of actual children given to the the view function. Count is {}, but got {} children", nav.section_heights.len(), children.len());
replacement in iced_nav_scrollable/src/lib.rs at line 222

[6.4261]→[6.4261:4295](∅→∅)

.zip(nav.sections.keys())

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[6.4295]

.zip(nav.section_heights.keys())
replacement in iced_nav_scrollable/src/lib.rs at line 232

[6.4602]→[6.4602:4633](∅→∅)

nav.offsets_ready = false;

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[6.4633]

nav.section_offsets
.iter_mut()
.for_each(|offset| *offset = 0.0);
nav.generation = nav.generation.wrapping_add(1);
replacement in iced_nav_scrollable/src/lib.rs at line 238

[6.4636]→[6.4636:4774](∅→∅)

fn update_offsets(nav: &mut NavScrollable) {
if !nav.offsets_ready {
debug_assert_eq!(nav.sections.len(), nav.offsets.len());

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[6.4774]

fn update_offsets_if_ready(nav: &mut NavScrollable) {
if nav.pending_tasks == Some(0) {
debug_assert_eq!(nav.section_heights.len(), nav.section_offsets.len());
replacement in iced_nav_scrollable/src/lib.rs at line 242

[6.4805]→[6.4805:5103](∅→∅)

nav.sections.values().enumerate().for_each(|(i, height)| {
// The current offset is the value of the acc
nav.offsets[i] = acc;
// Increment the acc with the height of this section
acc += *height;
});
nav.offsets_ready = true;

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nav.section_heights
.values()
.enumerate()
.for_each(|(i, height)| {
// The current offset is the value of the acc
nav.section_offsets[i] = acc;
// Increment the acc with the height of this section
acc += *height;
});
nav.needs_scrolling = if acc > nav.height {
NeedsScrolling::Yes
} else {
NeedsScrolling::No
};
nav.pending_tasks = None;
}
}

/// Produces a [`Task`] that queries the height of the contents of [`Scrollable`] with the
/// given [`Id`].
fn scrollable_height_task(id: impl Into<scrollable::Id>) -> Task<f32> {
let id = id.into();

struct SizeOp {
target: advanced::widget::Id,
height: Option<f32>,
}

impl advanced::widget::Operation<f32> for SizeOp {
fn scrollable(
&mut self,
id: Option<&advanced::widget::Id>,
_bounds: Rectangle,
content_bounds: Rectangle,
_translation: iced::Vector,
_state: &mut dyn advanced::widget::operation::Scrollable,
) {
if id == Some(&self.target) {
dbg!(&_bounds, &content_bounds);
self.height = Some(content_bounds.height);
return;
}
}

fn container(
&mut self,
_id: Option<&advanced::widget::Id>,
_bounds: Rectangle,
operate_on_children: &mut dyn FnMut(
&mut dyn advanced::widget::Operation<f32>,
),
) {
operate_on_children(self);
}

fn finish(&self) -> advanced::widget::operation::Outcome<f32> {
advanced::widget::operation::Outcome::Some(
self.height.expect("Must be able to determine the size. If this even panics, make the height optional and re-try the task when None"),
)
}
edit in iced_nav_scrollable/src/lib.rs at line 303

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advanced::widget::operate(SizeOp {
target: id.into(),
height: None,
})
replacement in iced_nav_scrollable/src/lib.rs at line 312

[6.5208]→[6.5208:5268](∅→∅)

fn height_task(id: impl Into<container::Id>) -> Task<f32> {

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fn container_height_task(id: impl Into<container::Id>) -> Task<f32> {
edit in iced_nav_scrollable/Cargo.toml at line 13

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workspace = true
[dependencies.iced_futures]
edit in Cargo.toml at line 42

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[workspace.dependencies.iced_futures]
git = "https://github.com/iced-rs/iced"
rev = "c952ea8485b00e58bdff153989f708553272e131"
# path = "../iced/futures"
replacement in Cargo.lock at line 446

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version = "0.8.3"

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version = "0.8.4"
replacement in Cargo.lock at line 448

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checksum = "98922d6a4cfbcb08820c69d8eeccc05bb1f29bfa06b4f5b1dbfe9a868bd7608e"

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checksum = "19135c0c7a60bfee564dbe44ab5ce0557c6bf3884e5291a50be76a15640c4fbd"
replacement in Cargo.lock at line 1889

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version = "0.13.1"

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version = "0.13.3"
replacement in Cargo.lock at line 1891

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checksum = "3fb2d69b19215e18bb912fa30f7ce15846e301408695e44e0ef719f1da9e19f2"

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checksum = "4ae047235e33e2829703574b54fdec96bfbad892062d97fed2f76022287de61b"
edit in Cargo.lock at line 2102

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"iced_futures",
replacement in Cargo.lock at line 2438

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version = "0.2.2"

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version = "0.2.3"
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checksum = "14d75c7014ddab93c232bc6bb9f64790d3dfd1d605199acd4b40b6d69e691e9f"

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checksum = "f6970fe7a5300b4b42e62c52efa0187540a5bef546c60edaf554ef595d2e6f0b"
replacement in Cargo.lock at line 2644

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version = "0.3.1"

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version = "0.3.2"
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checksum = "f5d4a7da358eff58addd2877a45865158f0d78c911d43a5784ceb7bbf52833b0"

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checksum = "00810f1d8b74be64b13dbf3db89ac67740615d6c891f0e7b6179326533011a07"
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version = "1.0.16"

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version = "1.0.17"
replacement in Cargo.lock at line 4068

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checksum = "a65f2e60fbf1063868558d69c6beacf412dc755f9fc020f514b7955fc914fe30"

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checksum = "52717f9a02b6965224f95ca2a81e2e0c5c43baacd28ca057577988930b6c3d5b"
replacement in Cargo.lock at line 4233

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version = "0.11.12"

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version = "0.11.20"
replacement in Cargo.lock at line 4235

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checksum = "d6a5f31fcf7500f9401fea858ea4ab5525c99f2322cfcee732c0e6c74208c0c6"

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checksum = "5825c26fddd16ab9f515930d49028a630efec172e903483c94796cfe31893e6b"
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version = "0.4.17"

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version = "0.4.18"
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checksum = "0f6fe2e33d02a98ee64423802e16df3de99c43e5cf5ff983767e1128b394c8ac"

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checksum = "7384255a918371b5af158218d131530f694de9ad3815ebdd0453a940485cb0fa"