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|
use crate::{
column,
input::{mouse, ButtonState},
layout, Element, Event, Hasher, Layout, Length, Point, Rectangle, Size,
Widget,
};
pub use iced_core::scrollable::State;
use std::f32;
use std::hash::Hash;
/// A scrollable [`Column`].
///
/// [`Column`]: ../column/struct.Column.html
pub type Scrollable<'a, Message, Renderer> =
iced_core::Scrollable<'a, Element<'a, Message, Renderer>>;
impl<'a, Message, Renderer> Widget<Message, Renderer>
for Scrollable<'a, Message, Renderer>
where
Renderer: self::Renderer + column::Renderer,
{
fn width(&self) -> Length {
Length::Fill
}
fn height(&self) -> Length {
self.height
}
fn layout(
&self,
renderer: &Renderer,
limits: &layout::Limits,
) -> layout::Node {
let limits = limits
.max_height(self.max_height)
.width(Length::Fill)
.height(self.height);
let child_limits = layout::Limits::new(
Size::new(limits.min().width, 0.0),
Size::new(limits.max().width, f32::INFINITY),
);
let content = self.content.layout(renderer, &child_limits);
let size = limits.resolve(content.size());
layout::Node::with_children(size, vec![content])
}
fn on_event(
&mut self,
event: Event,
layout: Layout<'_>,
cursor_position: Point,
messages: &mut Vec<Message>,
renderer: &Renderer,
) {
let bounds = layout.bounds();
let is_mouse_over = bounds.contains(cursor_position);
let content = layout.children().next().unwrap();
let content_bounds = content.bounds();
let is_mouse_over_scrollbar = renderer.is_mouse_over_scrollbar(
bounds,
content_bounds,
cursor_position,
);
// TODO: Event capture. Nested scrollables should capture scroll events.
if is_mouse_over {
match event {
Event::Mouse(mouse::Event::WheelScrolled { delta }) => {
match delta {
mouse::ScrollDelta::Lines { y, .. } => {
// TODO: Configurable speed (?)
self.state.scroll(y * 15.0, bounds, content_bounds);
}
mouse::ScrollDelta::Pixels { y, .. } => {
self.state.scroll(y, bounds, content_bounds);
}
}
}
_ => {}
}
}
if self.state.is_scrollbar_grabbed() || is_mouse_over_scrollbar {
match event {
Event::Mouse(mouse::Event::Input {
button: mouse::Button::Left,
state,
}) => match state {
ButtonState::Pressed => {
self.state.scroll_to(
cursor_position.y / (bounds.y + bounds.height),
bounds,
content_bounds,
);
self.state.scrollbar_grabbed_at = Some(cursor_position);
}
ButtonState::Released => {
self.state.scrollbar_grabbed_at = None;
}
},
Event::Mouse(mouse::Event::CursorMoved { .. }) => {
if let Some(scrollbar_grabbed_at) =
self.state.scrollbar_grabbed_at
{
let ratio = content_bounds.height / bounds.height;
let delta = scrollbar_grabbed_at.y - cursor_position.y;
self.state.scroll(
delta * ratio,
bounds,
content_bounds,
);
self.state.scrollbar_grabbed_at = Some(cursor_position);
}
}
_ => {}
}
}
let cursor_position = if is_mouse_over
&& !(is_mouse_over_scrollbar
|| self.state.scrollbar_grabbed_at.is_some())
{
Point::new(
cursor_position.x,
cursor_position.y
+ self.state.offset(bounds, content_bounds) as f32,
)
} else {
// TODO: Make `cursor_position` an `Option<Point>` so we can encode
// cursor availability.
// This will probably happen naturally once we add multi-window
// support.
Point::new(cursor_position.x, -1.0)
};
self.content.on_event(
event,
content,
cursor_position,
messages,
renderer,
)
}
fn draw(
&self,
renderer: &mut Renderer,
layout: Layout<'_>,
cursor_position: Point,
) -> Renderer::Output {
let bounds = layout.bounds();
let content_layout = layout.children().next().unwrap();
self::Renderer::draw(
renderer,
&self,
bounds,
content_layout,
cursor_position,
)
}
fn hash_layout(&self, state: &mut Hasher) {
std::any::TypeId::of::<Scrollable<'static, (), ()>>().hash(state);
self.height.hash(state);
self.max_height.hash(state);
self.content.hash_layout(state)
}
}
pub trait Renderer: crate::Renderer + Sized {
fn is_mouse_over_scrollbar(
&self,
bounds: Rectangle,
content_bounds: Rectangle,
cursor_position: Point,
) -> bool;
fn draw<Message>(
&mut self,
scrollable: &Scrollable<'_, Message, Self>,
bounds: Rectangle,
content_layout: Layout<'_>,
cursor_position: Point,
) -> Self::Output;
}
impl<'a, Message, Renderer> From<Scrollable<'a, Message, Renderer>>
for Element<'a, Message, Renderer>
where
Renderer: 'a + self::Renderer + column::Renderer,
Message: 'static,
{
fn from(
scrollable: Scrollable<'a, Message, Renderer>,
) -> Element<'a, Message, Renderer> {
Element::new(scrollable)
}
}
|
