diff options
Diffstat (limited to 'native/src/widget/scrollable.rs')
| -rw-r--r-- | native/src/widget/scrollable.rs | 180 |
1 files changed, 157 insertions, 23 deletions
diff --git a/native/src/widget/scrollable.rs b/native/src/widget/scrollable.rs index e23ab06a..68da2e67 100644 --- a/native/src/widget/scrollable.rs +++ b/native/src/widget/scrollable.rs @@ -4,8 +4,9 @@ use crate::event::{self, Event}; use crate::layout; use crate::mouse; use crate::overlay; +use crate::touch; use crate::{ - Align, Clipboard, Column, Element, Hasher, Layout, Length, Point, + Align, Clipboard, Column, Element, Hasher, Layout, Length, Padding, Point, Rectangle, Size, Vector, Widget, }; @@ -22,6 +23,7 @@ pub struct Scrollable<'a, Message, Renderer: self::Renderer> { scrollbar_margin: u16, scroller_width: u16, content: Column<'a, Message, Renderer>, + on_scroll: Option<Box<dyn Fn(f32) -> Message>>, style: Renderer::Style, } @@ -36,6 +38,7 @@ impl<'a, Message, Renderer: self::Renderer> Scrollable<'a, Message, Renderer> { scrollbar_margin: 0, scroller_width: 10, content: Column::new(), + on_scroll: None, style: Renderer::Style::default(), } } @@ -50,9 +53,9 @@ impl<'a, Message, Renderer: self::Renderer> Scrollable<'a, Message, Renderer> { self } - /// Sets the padding of the [`Scrollable`]. - pub fn padding(mut self, units: u16) -> Self { - self.content = self.content.padding(units); + /// Sets the [`Padding`] of the [`Scrollable`]. + pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self { + self.content = self.content.padding(padding); self } @@ -100,12 +103,22 @@ impl<'a, Message, Renderer: self::Renderer> Scrollable<'a, Message, Renderer> { } /// Sets the scroller width of the [`Scrollable`] . - /// Silently enforces a minimum value of 1. + /// + /// It silently enforces a minimum value of 1. pub fn scroller_width(mut self, scroller_width: u16) -> Self { self.scroller_width = scroller_width.max(1); self } + /// Sets a function to call when the [`Scrollable`] is scrolled. + /// + /// The function takes the new relative offset of the [`Scrollable`] + /// (e.g. `0` means top, while `1` means bottom). + pub fn on_scroll(mut self, f: impl Fn(f32) -> Message + 'static) -> Self { + self.on_scroll = Some(Box::new(f)); + self + } + /// Sets the style of the [`Scrollable`] . pub fn style(mut self, style: impl Into<Renderer::Style>) -> Self { self.style = style.into(); @@ -120,6 +133,24 @@ impl<'a, Message, Renderer: self::Renderer> Scrollable<'a, Message, Renderer> { self.content = self.content.push(child); self } + + fn notify_on_scroll( + &self, + bounds: Rectangle, + content_bounds: Rectangle, + messages: &mut Vec<Message>, + ) { + if content_bounds.height <= bounds.height { + return; + } + + if let Some(on_scroll) = &self.on_scroll { + messages.push(on_scroll( + self.state.offset.absolute(bounds, content_bounds) + / (content_bounds.height - bounds.height), + )); + } + } } impl<'a, Message, Renderer> Widget<Message, Renderer> @@ -161,9 +192,9 @@ where event: Event, layout: Layout<'_>, cursor_position: Point, - messages: &mut Vec<Message>, renderer: &Renderer, - clipboard: Option<&dyn Clipboard>, + clipboard: &mut dyn Clipboard, + messages: &mut Vec<Message>, ) -> event::Status { let bounds = layout.bounds(); let is_mouse_over = bounds.contains(cursor_position); @@ -204,9 +235,9 @@ where event.clone(), content, cursor_position, - messages, renderer, clipboard, + messages, ) }; @@ -227,6 +258,45 @@ where } } + self.notify_on_scroll(bounds, content_bounds, messages); + + return event::Status::Captured; + } + Event::Touch(event) => { + match event { + touch::Event::FingerPressed { .. } => { + self.state.scroll_box_touched_at = + Some(cursor_position); + } + touch::Event::FingerMoved { .. } => { + if let Some(scroll_box_touched_at) = + self.state.scroll_box_touched_at + { + let delta = + cursor_position.y - scroll_box_touched_at.y; + + self.state.scroll( + delta, + bounds, + content_bounds, + ); + + self.state.scroll_box_touched_at = + Some(cursor_position); + + self.notify_on_scroll( + bounds, + content_bounds, + messages, + ); + } + } + touch::Event::FingerLifted { .. } + | touch::Event::FingerLost { .. } => { + self.state.scroll_box_touched_at = None; + } + } + return event::Status::Captured; } _ => {} @@ -237,12 +307,15 @@ where match event { Event::Mouse(mouse::Event::ButtonReleased( mouse::Button::Left, - )) => { + )) + | Event::Touch(touch::Event::FingerLifted { .. }) + | Event::Touch(touch::Event::FingerLost { .. }) => { self.state.scroller_grabbed_at = None; return event::Status::Captured; } - Event::Mouse(mouse::Event::CursorMoved { .. }) => { + Event::Mouse(mouse::Event::CursorMoved { .. }) + | Event::Touch(touch::Event::FingerMoved { .. }) => { if let (Some(scrollbar), Some(scroller_grabbed_at)) = (scrollbar, self.state.scroller_grabbed_at) { @@ -255,6 +328,8 @@ where content_bounds, ); + self.notify_on_scroll(bounds, content_bounds, messages); + return event::Status::Captured; } } @@ -264,7 +339,8 @@ where match event { Event::Mouse(mouse::Event::ButtonPressed( mouse::Button::Left, - )) => { + )) + | Event::Touch(touch::Event::FingerPressed { .. }) => { if let Some(scrollbar) = scrollbar { if let Some(scroller_grabbed_at) = scrollbar.grab_scroller(cursor_position) @@ -281,6 +357,12 @@ where self.state.scroller_grabbed_at = Some(scroller_grabbed_at); + self.notify_on_scroll( + bounds, + content_bounds, + messages, + ); + return event::Status::Captured; } } @@ -382,10 +464,44 @@ where } /// The local state of a [`Scrollable`]. -#[derive(Debug, Clone, Copy, Default)] +#[derive(Debug, Clone, Copy)] pub struct State { scroller_grabbed_at: Option<f32>, - offset: f32, + scroll_box_touched_at: Option<Point>, + offset: Offset, +} + +impl Default for State { + fn default() -> Self { + Self { + scroller_grabbed_at: None, + scroll_box_touched_at: None, + offset: Offset::Absolute(0.0), + } + } +} + +/// The local state of a [`Scrollable`]. +#[derive(Debug, Clone, Copy)] +enum Offset { + Absolute(f32), + Relative(f32), +} + +impl Offset { + fn absolute(self, bounds: Rectangle, content_bounds: Rectangle) -> f32 { + match self { + Self::Absolute(absolute) => { + let hidden_content = + (content_bounds.height - bounds.height).max(0.0); + + absolute.min(hidden_content) + } + Self::Relative(percentage) => { + ((content_bounds.height - bounds.height) * percentage).max(0.0) + } + } + } } impl State { @@ -406,13 +522,14 @@ impl State { return; } - self.offset = (self.offset - delta_y) - .max(0.0) - .min((content_bounds.height - bounds.height) as f32); + self.offset = Offset::Absolute( + (self.offset.absolute(bounds, content_bounds) - delta_y) + .max(0.0) + .min((content_bounds.height - bounds.height) as f32), + ); } - /// Moves the scroll position to a relative amount, given the bounds of - /// the [`Scrollable`] and its contents. + /// Scrolls the [`Scrollable`] to a relative amount. /// /// `0` represents scrollbar at the top, while `1` represents scrollbar at /// the bottom. @@ -422,23 +539,40 @@ impl State { bounds: Rectangle, content_bounds: Rectangle, ) { + self.snap_to(percentage); + self.unsnap(bounds, content_bounds); + } + + /// Snaps the scroll position to a relative amount. + /// + /// `0` represents scrollbar at the top, while `1` represents scrollbar at + /// the bottom. + pub fn snap_to(&mut self, percentage: f32) { + self.offset = Offset::Relative(percentage.max(0.0).min(1.0)); + } + + /// Unsnaps the current scroll position, if snapped, given the bounds of the + /// [`Scrollable`] and its contents. + pub fn unsnap(&mut self, bounds: Rectangle, content_bounds: Rectangle) { self.offset = - ((content_bounds.height - bounds.height) * percentage).max(0.0); + Offset::Absolute(self.offset.absolute(bounds, content_bounds)); } /// Returns the current scrolling offset of the [`State`], given the bounds /// of the [`Scrollable`] and its contents. pub fn offset(&self, bounds: Rectangle, content_bounds: Rectangle) -> u32 { - let hidden_content = - (content_bounds.height - bounds.height).max(0.0).round() as u32; - - self.offset.min(hidden_content as f32) as u32 + self.offset.absolute(bounds, content_bounds) as u32 } /// Returns whether the scroller is currently grabbed or not. pub fn is_scroller_grabbed(&self) -> bool { self.scroller_grabbed_at.is_some() } + + /// Returns whether the scroll box is currently touched or not. + pub fn is_scroll_box_touched(&self) -> bool { + self.scroll_box_touched_at.is_some() + } } /// The scrollbar of a [`Scrollable`]. |