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use crate::direction::Direction;
use crate::event::{AnyCb, Event, EventResult};
use crate::view::{scroll, ScrollStrategy, Selector, View};
use crate::{Printer, Rect, Vec2, With};
/// Wraps a view in a scrollable area.
pub struct ScrollView<V> {
/// The wrapped view.
inner: V,
core: scroll::Core,
}
impl_scroller!(ScrollView<V>::core);
impl<V> ScrollView<V>
where
V: View,
{
/// Creates a new ScrollView around `view`.
pub fn new(inner: V) -> Self {
ScrollView {
inner,
core: scroll::Core::new(),
}
}
/// Returns the viewport in the inner content.
pub fn content_viewport(&self) -> Rect {
self.core.content_viewport()
}
/// Returns the size of the content view, as it was on the last layout
/// phase.
///
/// This is only the size the content _thinks_ it has, and may be larger
/// than the actual size used by this `ScrollView`.
pub fn inner_size(&self) -> Vec2 {
self.core.inner_size()
}
/// Returns `true` if the top row of the content is in view.
pub fn is_at_top(&self) -> bool {
self.content_viewport().top() == 0
}
/// Returns `true` if the bottom row of the content is in view.
pub fn is_at_bottom(&self) -> bool {
// The viewport indicates which row is in view.
// So the bottom row will be (height - 1)
(1 + self.content_viewport().bottom()) >= self.inner_size().y
}
/// Return `true` if the left-most column of the content is in view.
pub fn is_at_left_edge(&self) -> bool {
self.content_viewport().left() == 0
}
/// Return `true` if the right-most column of the content is in view.
pub fn is_at_right_edge(&self) -> bool {
// The viewport indicates which row is in view.
// So the right-most column will be (width - 1)
(1 + self.content_viewport().right()) >= self.inner_size().x
}
/// Defines the way scrolling is adjusted on content or size change.
///
/// The scroll strategy defines how the scrolling position is adjusted
/// when the size of the view or the content change.
///
/// It is reset to `ScrollStrategy::KeepRow` whenever the user scrolls
/// manually.
pub fn set_scroll_strategy(&mut self, strategy: ScrollStrategy) {
self.core.set_scroll_strategy(strategy);
}
/// Defines the way scrolling is adjusted on content or size change.
///
/// Chainable variant.
pub fn scroll_strategy(self, strategy: ScrollStrategy) -> Self {
self.with(|s| s.set_scroll_strategy(strategy))
}
/// Control whether scroll bars are visibile.
///
/// Defaults to `true`.
pub fn set_show_scrollbars(&mut self, show_scrollbars: bool) {
self.core.set_show_scrollbars(show_scrollbars);
}
/// Control whether scroll bars are visibile.
///
/// Chainable variant
pub fn show_scrollbars(self, show_scrollbars: bool) -> Self {
self.with(|s| s.set_show_scrollbars(show_scrollbars))
}
/// Sets the scroll offset to the given value
pub fn set_offset<S>(&mut self, offset: S)
where
S: Into<Vec2>,
{
self.core.set_offset(offset);
}
/// Controls whether this view can scroll vertically.
///
/// Defaults to `true`.
pub fn set_scroll_y(&mut self, enabled: bool) {
self.core.set_scroll_y(enabled);
}
/// Controls whether this view can scroll horizontally.
///
/// Defaults to `false`.
pub fn set_scroll_x(&mut self, enabled: bool) {
self.core.set_scroll_x(enabled);
}
/// Controls whether this view can scroll vertically.
///
/// Defaults to `true`.
///
/// Chainable variant.
pub fn scroll_y(self, enabled: bool) -> Self {
self.with(|s| s.set_scroll_y(enabled))
}
/// Controls whether this view can scroll horizontally.
///
/// Defaults to `false`.
///
/// Chainable variant.
pub fn scroll_x(self, enabled: bool) -> Self {
self.with(|s| s.set_scroll_x(enabled))
}
/// Programmatically scroll to the top of the view.
pub fn scroll_to_top(&mut self) {
self.core.scroll_to_top();
}
/// Programmatically scroll to the bottom of the view.
pub fn scroll_to_bottom(&mut self) {
self.core.scroll_to_bottom();
}
/// Programmatically scroll to the leftmost side of the view.
pub fn scroll_to_left(&mut self) {
self.core.scroll_to_left();
}
/// Programmatically scroll to the rightmost side of the view.
pub fn scroll_to_right(&mut self) {
self.core.scroll_to_right();
}
/// Programmatically scroll until the child's important area is in view.
pub fn scroll_to_important_area(&mut self) {
let important_area = self.inner.important_area(self.core.last_size());
self.core.scroll_to_rect(important_area);
}
/// Returns the wrapped view.
pub fn into_inner(self) -> V {
self.inner
}
inner_getters!(self.inner: V);
}
impl<V> View for ScrollView<V>
where
V: View,
{
fn draw(&self, printer: &Printer<'_, '_>) {
scroll::draw(self, printer, |s, p| s.inner.draw(p));
}
fn on_event(&mut self, event: Event) -> EventResult {
scroll::on_event(
self,
event,
|s, e| s.inner.on_event(e),
|s, si| s.inner.important_area(si),
)
}
fn layout(&mut self, size: Vec2) {
scroll::layout(
self,
size,
self.inner.needs_relayout(),
|s, si| s.inner.layout(si),
|s, c| s.inner.required_size(c),
);
}
fn needs_relayout(&self) -> bool {
self.core.needs_relayout() || self.inner.needs_relayout()
}
fn required_size(&mut self, constraint: Vec2) -> Vec2 {
scroll::required_size(
self,
constraint,
self.inner.needs_relayout(),
|s, c| s.inner.required_size(c),
)
}
fn call_on_any<'a>(&mut self, selector: &Selector<'_>, cb: AnyCb<'a>) {
// TODO: should we scroll_to_important_area here?
// The callback may change the focus or some other thing.
self.inner.call_on_any(selector, cb)
}
fn focus_view(&mut self, selector: &Selector<'_>) -> Result<(), ()> {
self.inner.focus_view(selector).map(|()| {
self.scroll_to_important_area();
})
}
fn take_focus(&mut self, source: Direction) -> bool {
// If the inner view takes focus, re-align the important area.
if self.inner.take_focus(source) {
self.scroll_to_important_area();
true
} else {
self.core.is_scrolling().any()
}
}
fn important_area(&self, size: Vec2) -> Rect {
scroll::important_area(self, size, |s, si| s.inner.important_area(si))
}
}