Introduce snap_to and unsnap to scrollable::State
This commit is contained in:
Héctor Ramón
parent
f7d6e40bf0
commit
827577c179
@ -10,7 +10,7 @@ use crate::{
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Rectangle, Size, Vector, Widget,
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};
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use std::{cell::RefCell, f32, hash::Hash, u32};
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use std::{f32, hash::Hash, u32};
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/// A widget that can vertically display an infinite amount of content with a
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/// scrollbar.
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@ -24,8 +24,6 @@ pub struct Scrollable<'a, Message, Renderer: self::Renderer> {
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scroller_width: u16,
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content: Column<'a, Message, Renderer>,
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style: Renderer::Style,
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on_scroll: Option<Box<dyn Fn(f32, f32) -> Message>>,
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snap_to_bottom: bool,
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}
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impl<'a, Message, Renderer: self::Renderer> Scrollable<'a, Message, Renderer> {
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@ -40,36 +38,9 @@ impl<'a, Message, Renderer: self::Renderer> Scrollable<'a, Message, Renderer> {
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scroller_width: 10,
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content: Column::new(),
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style: Renderer::Style::default(),
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on_scroll: None,
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snap_to_bottom: false,
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}
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}
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/// Whether to set the [`Scrollable`] to snap to bottom when the user
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/// scrolls to bottom or not. This will keep the scrollable at the bottom
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/// even if new content is added to the scrollable.
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///
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/// [`Scrollable`]: struct.Scrollable.html
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pub fn snap_to_bottom(mut self, snap: bool) -> Self {
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self.snap_to_bottom = snap;
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self
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}
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/// Sets a function to call when the [`Scrollable`] is scrolled.
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///
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/// The function takes two `f32` as arguments. First is the percentage of
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/// where the scrollable is at right now. Second is the percentage of where
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/// the scrollable was *before*. `0.0` means top and `1.0` means bottom.
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///
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/// [`Scrollable`]: struct.Scrollable.html
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pub fn on_scroll<F>(mut self, message_constructor: F) -> Self
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where
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F: 'static + Fn(f32, f32) -> Message,
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{
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self.on_scroll = Some(Box::new(message_constructor));
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self
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}
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/// Sets the vertical spacing _between_ elements.
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///
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/// Custom margins per element do not exist in Iced. You should use this
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@ -215,7 +186,7 @@ where
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.map(|scrollbar| scrollbar.is_mouse_over(cursor_position))
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.unwrap_or(false);
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let mut event_status = {
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let event_status = {
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let cursor_position = if is_mouse_over && !is_mouse_over_scrollbar {
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Point::new(
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cursor_position.x,
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@ -240,78 +211,99 @@ where
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)
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};
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if let event::Status::Ignored = event_status {
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self.state.prev_offset = self.state.offset(bounds, content_bounds);
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if let event::Status::Captured = event_status {
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return event::Status::Captured;
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}
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if is_mouse_over {
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match event {
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Event::Mouse(mouse::Event::WheelScrolled { delta }) => {
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match delta {
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mouse::ScrollDelta::Lines { y, .. } => {
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// TODO: Configurable speed (?)
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self.state.scroll(y * 60.0, bounds, content_bounds);
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}
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mouse::ScrollDelta::Pixels { y, .. } => {
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self.state.scroll(y, bounds, content_bounds);
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}
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}
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return event::Status::Captured;
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}
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Event::Touch(event) => {
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match event {
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touch::Event::FingerPressed { .. } => {
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self.state.scroll_box_touched_at =
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Some(cursor_position);
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}
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touch::Event::FingerMoved { .. } => {
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if let Some(scroll_box_touched_at) =
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self.state.scroll_box_touched_at
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{
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let delta =
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cursor_position.y - scroll_box_touched_at.y;
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if is_mouse_over {
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match event {
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Event::Mouse(mouse::Event::WheelScrolled { delta }) => {
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match delta {
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mouse::ScrollDelta::Lines { y, .. } => {
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// TODO: Configurable speed (?)
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self.state.scroll(
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y * 60.0,
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delta,
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bounds,
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content_bounds,
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);
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}
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mouse::ScrollDelta::Pixels { y, .. } => {
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self.state.scroll(y, bounds, content_bounds);
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}
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}
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event_status = event::Status::Captured;
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}
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Event::Touch(event) => {
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match event {
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touch::Event::FingerPressed { .. } => {
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self.state.scroll_box_touched_at =
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Some(cursor_position);
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}
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touch::Event::FingerMoved { .. } => {
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if let Some(scroll_box_touched_at) =
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self.state.scroll_box_touched_at
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{
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let delta = cursor_position.y
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- scroll_box_touched_at.y;
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self.state.scroll(
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delta,
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bounds,
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content_bounds,
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);
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self.state.scroll_box_touched_at =
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Some(cursor_position);
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}
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}
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touch::Event::FingerLifted { .. }
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| touch::Event::FingerLost { .. } => {
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self.state.scroll_box_touched_at = None;
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}
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}
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event_status = event::Status::Captured;
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touch::Event::FingerLifted { .. }
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| touch::Event::FingerLost { .. } => {
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self.state.scroll_box_touched_at = None;
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}
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}
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_ => {}
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return event::Status::Captured;
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}
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_ => {}
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}
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}
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if self.state.is_scroller_grabbed() {
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match event {
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Event::Mouse(mouse::Event::ButtonReleased(
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mouse::Button::Left,
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))
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| Event::Touch(touch::Event::FingerLifted { .. })
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| Event::Touch(touch::Event::FingerLost { .. }) => {
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self.state.scroller_grabbed_at = None;
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if self.state.is_scroller_grabbed() {
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match event {
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Event::Mouse(mouse::Event::ButtonReleased(
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mouse::Button::Left,
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))
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| Event::Touch(touch::Event::FingerLifted { .. })
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| Event::Touch(touch::Event::FingerLost { .. }) => {
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self.state.scroller_grabbed_at = None;
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event_status = event::Status::Captured;
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return event::Status::Captured;
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}
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Event::Mouse(mouse::Event::CursorMoved { .. })
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| Event::Touch(touch::Event::FingerMoved { .. }) => {
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if let (Some(scrollbar), Some(scroller_grabbed_at)) =
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(scrollbar, self.state.scroller_grabbed_at)
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{
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self.state.scroll_to(
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scrollbar.scroll_percentage(
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scroller_grabbed_at,
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cursor_position,
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),
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bounds,
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content_bounds,
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);
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return event::Status::Captured;
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}
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Event::Mouse(mouse::Event::CursorMoved { .. })
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| Event::Touch(touch::Event::FingerMoved { .. }) => {
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if let (Some(scrollbar), Some(scroller_grabbed_at)) =
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(scrollbar, self.state.scroller_grabbed_at)
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}
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_ => {}
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}
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} else if is_mouse_over_scrollbar {
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match event {
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Event::Mouse(mouse::Event::ButtonPressed(
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mouse::Button::Left,
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))
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| Event::Touch(touch::Event::FingerPressed { .. }) => {
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if let Some(scrollbar) = scrollbar {
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if let Some(scroller_grabbed_at) =
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scrollbar.grab_scroller(cursor_position)
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{
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self.state.scroll_to(
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scrollbar.scroll_percentage(
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@ -322,71 +314,18 @@ where
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content_bounds,
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);
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event_status = event::Status::Captured;
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self.state.scroller_grabbed_at =
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Some(scroller_grabbed_at);
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return event::Status::Captured;
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}
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}
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_ => {}
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}
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} else if is_mouse_over_scrollbar {
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match event {
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Event::Mouse(mouse::Event::ButtonPressed(
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mouse::Button::Left,
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))
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| Event::Touch(touch::Event::FingerPressed { .. }) => {
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if let Some(scrollbar) = scrollbar {
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if let Some(scroller_grabbed_at) =
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scrollbar.grab_scroller(cursor_position)
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{
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self.state.scroll_to(
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scrollbar.scroll_percentage(
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scroller_grabbed_at,
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cursor_position,
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),
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bounds,
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content_bounds,
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);
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self.state.scroller_grabbed_at =
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Some(scroller_grabbed_at);
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event_status = event::Status::Captured;
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}
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}
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}
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_ => {}
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}
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_ => {}
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}
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}
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if let event::Status::Captured = event_status {
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if self.snap_to_bottom {
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let new_offset = self.state.offset(bounds, content_bounds);
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if new_offset < self.state.prev_offset {
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self.state.snap_to_bottom = false;
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} else {
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let scroll_perc = new_offset as f32
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/ (content_bounds.height - bounds.height);
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if scroll_perc >= 1.0 - f32::EPSILON {
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self.state.snap_to_bottom = true;
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}
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}
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}
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if let Some(on_scroll) = &self.on_scroll {
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messages.push(on_scroll(
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self.state.offset(bounds, content_bounds) as f32
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/ (content_bounds.height - bounds.height),
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self.state.prev_offset as f32
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/ (content_bounds.height - bounds.height),
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));
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}
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event::Status::Captured
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} else {
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event::Status::Ignored
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}
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event::Status::Ignored
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}
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fn draw(
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@ -400,15 +339,6 @@ where
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let bounds = layout.bounds();
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let content_layout = layout.children().next().unwrap();
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let content_bounds = content_layout.bounds();
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if self.state.snap_to_bottom {
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self.state.scroll_to(1.0, bounds, content_bounds);
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}
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if let Some(scroll_to) = self.state.scroll_to.borrow_mut().take() {
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self.state.scroll_to(scroll_to, bounds, content_bounds);
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}
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let offset = self.state.offset(bounds, content_bounds);
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let scrollbar = renderer.scrollbar(
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bounds,
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@ -488,14 +418,44 @@ where
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}
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/// The local state of a [`Scrollable`].
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#[derive(Debug, Clone, Default)]
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#[derive(Debug, Clone, Copy)]
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pub struct State {
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scroller_grabbed_at: Option<f32>,
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scroll_box_touched_at: Option<Point>,
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prev_offset: u32,
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snap_to_bottom: bool,
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offset: RefCell<f32>,
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scroll_to: RefCell<Option<f32>>,
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offset: Offset,
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}
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impl Default for State {
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fn default() -> Self {
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Self {
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scroller_grabbed_at: None,
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scroll_box_touched_at: None,
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offset: Offset::Absolute(0.0),
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}
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}
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}
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/// The local state of a [`Scrollable`].
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#[derive(Debug, Clone, Copy)]
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enum Offset {
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Absolute(f32),
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Relative(f32),
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}
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impl Offset {
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fn absolute(self, bounds: Rectangle, content_bounds: Rectangle) -> f32 {
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match self {
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Self::Absolute(absolute) => {
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let hidden_content =
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(content_bounds.height - bounds.height).max(0.0);
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absolute.min(hidden_content)
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}
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Self::Relative(percentage) => {
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((content_bounds.height - bounds.height) * percentage).max(0.0)
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}
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}
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}
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}
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impl State {
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@ -516,51 +476,46 @@ impl State {
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return;
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}
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let offset_val = *self.offset.borrow();
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*self.offset.borrow_mut() = (offset_val - delta_y)
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.max(0.0)
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.min((content_bounds.height - bounds.height) as f32);
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self.offset = Offset::Absolute(
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(self.offset.absolute(bounds, content_bounds) - delta_y)
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.max(0.0)
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.min((content_bounds.height - bounds.height) as f32),
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);
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}
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/// Moves the scroll position to a relative amount, given the bounds of
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/// the [`Scrollable`] and its contents.
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/// Scrolls the [`Scrollable`] to a relative amount.
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///
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/// `0` represents scrollbar at the top, while `1` represents scrollbar at
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/// the bottom.
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pub fn scroll_to(
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&self,
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&mut self,
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percentage: f32,
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bounds: Rectangle,
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content_bounds: Rectangle,
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) {
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*self.offset.borrow_mut() =
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((content_bounds.height - bounds.height) * percentage).max(0.0);
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self.snap_to(percentage);
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self.unsnap(bounds, content_bounds);
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}
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/// Marks the scrollable to scroll to `perc` percentage (between 0.0 and 1.0)
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/// in the next `draw` call.
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/// Snaps the scroll position to a relative amount.
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///
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/// [`Scrollable`]: struct.Scrollable.html
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/// [`State`]: struct.State.html
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pub fn scroll_to_percentage(&mut self, perc: f32) {
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*self.scroll_to.borrow_mut() = Some(perc.max(0.0).min(1.0));
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/// `0` represents scrollbar at the top, while `1` represents scrollbar at
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/// the bottom.
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pub fn snap_to(&mut self, percentage: f32) {
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self.offset = Offset::Relative(percentage.max(0.0).min(1.0));
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}
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/// Marks the scrollable to scroll to bottom in the next `draw` call.
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///
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/// [`Scrollable`]: struct.Scrollable.html
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/// [`State`]: struct.State.html
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pub fn scroll_to_bottom(&mut self) {
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self.scroll_to_percentage(1.0);
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/// Unsnaps the current scroll position, if snapped, given the bounds of the
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/// [`Scrollable`] and its contents.
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pub fn unsnap(&mut self, bounds: Rectangle, content_bounds: Rectangle) {
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self.offset =
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Offset::Absolute(self.offset.absolute(bounds, content_bounds));
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}
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/// Returns the current scrolling offset of the [`State`], given the bounds
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/// of the [`Scrollable`] and its contents.
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pub fn offset(&self, bounds: Rectangle, content_bounds: Rectangle) -> u32 {
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let hidden_content =
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(content_bounds.height - bounds.height).max(0.0).round() as u32;
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self.offset.borrow().min(hidden_content as f32) as u32
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self.offset.absolute(bounds, content_bounds) as u32
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}
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/// Returns whether the scroller is currently grabbed or not.
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