use std::{any::Any, cell::Cell, fmt::Debug, ops::Range, rc::Rc, sync::Arc}; use crate::{prelude::*, px, relative, IntoElement};use gpui::{ point, quad, Along, App, Axis as ScrollbarAxis, Bounds, ContentMask, Corners, Edges, Element, ElementId, Entity, EntityId, GlobalElementId, Hitbox, Hsla, LayoutId, MouseDownEvent, MouseMoveEvent, MouseUpEvent, Pixels, Point, ScrollHandle, ScrollWheelEvent, Size, Style, UniformListScrollHandle, Window,}; pub struct Scrollbar { thumb: Range<f32>, state: ScrollbarState, kind: ScrollbarAxis,} impl ScrollableHandle for UniformListScrollHandle { fn content_size(&self) -> Option<ContentSize> { Some(ContentSize { size: self.0.borrow().last_item_size.map(|size| size.contents)?, scroll_adjustment: None, }) } fn set_offset(&self, point: Point<Pixels>) { self.0.borrow().base_handle.set_offset(point); } fn offset(&self) -> Point<Pixels> { self.0.borrow().base_handle.offset() } fn viewport(&self) -> Bounds<Pixels> { self.0.borrow().base_handle.bounds() } fn as_any(&self) -> &dyn Any { self }} impl ScrollableHandle for ScrollHandle { fn content_size(&self) -> Option<ContentSize> { let last_children_index = self.children_count().checked_sub(1)?; let mut last_item = self.bounds_for_item(last_children_index)?; let mut scroll_adjustment = None; if last_children_index != 0 { // todo: PO: this is slightly wrong for horizontal scrollbar, as the last item is not necessarily the longest one. let first_item = self.bounds_for_item(0)?; last_item.size.height += last_item.origin.y; last_item.size.width += last_item.origin.x; scroll_adjustment = Some(first_item.origin); last_item.size.height -= first_item.origin.y; last_item.size.width -= first_item.origin.x; } Some(ContentSize { size: last_item.size, scroll_adjustment, }) } fn set_offset(&self, point: Point<Pixels>) { self.set_offset(point); } fn offset(&self) -> Point<Pixels> { self.offset() } fn viewport(&self) -> Bounds<Pixels> { self.bounds() } fn as_any(&self) -> &dyn Any { self }} #[derive(Debug)]pub struct ContentSize { pub size: Size<Pixels>, pub scroll_adjustment: Option<Point<Pixels>>,} pub trait ScrollableHandle: Debug + 'static { fn content_size(&self) -> Option<ContentSize>; fn set_offset(&self, point: Point<Pixels>); fn offset(&self) -> Point<Pixels>; fn viewport(&self) -> Bounds<Pixels>; fn as_any(&self) -> &dyn Any;} /// A scrollbar state that should be persisted across frames.#[derive(Clone, Debug)]pub struct ScrollbarState { // If Some(), there's an active drag, offset by percentage from the origin of a thumb. drag: Rc<Cell<Option<Pixels>>>, parent_id: Option<EntityId>, scroll_handle: Arc<dyn ScrollableHandle>,} impl ScrollbarState { pub fn new(scroll: impl ScrollableHandle) -> Self { Self { drag: Default::default(), parent_id: None, scroll_handle: Arc::new(scroll), } } /// Set a parent model which should be notified whenever this Scrollbar gets a scroll event. pub fn parent_entity<V: 'static>(mut self, v: &Entity<V>) -> Self { self.parent_id = Some(v.entity_id()); self } pub fn scroll_handle(&self) -> &Arc<dyn ScrollableHandle> { &self.scroll_handle } pub fn is_dragging(&self) -> bool { self.drag.get().is_some() } fn thumb_range(&self, axis: ScrollbarAxis) -> Option<Range<f32>> { const MINIMUM_THUMB_SIZE: f32 = 25.; let ContentSize { size: main_dimension_size, scroll_adjustment, } = self.scroll_handle.content_size()?; let content_size = main_dimension_size.along(axis).0; let mut current_offset = self.scroll_handle.offset().along(axis).min(px(0.)).abs().0; if let Some(adjustment) = scroll_adjustment.and_then(|adjustment| { let adjust = adjustment.along(axis).0; if adjust < 0.0 { Some(adjust) } else { None } }) { current_offset -= adjustment; } let viewport_size = self.scroll_handle.viewport().size.along(axis).0; if content_size < viewport_size { return None; } let visible_percentage = viewport_size / content_size; let thumb_size = MINIMUM_THUMB_SIZE.max(viewport_size * visible_percentage); if thumb_size > viewport_size { return None; } let max_offset = content_size - viewport_size; current_offset = current_offset.clamp(0., max_offset); let start_offset = (current_offset / max_offset) * (viewport_size - thumb_size); let thumb_percentage_start = start_offset / viewport_size; let thumb_percentage_end = (start_offset + thumb_size) / viewport_size; Some(thumb_percentage_start..thumb_percentage_end) }} impl Scrollbar { pub fn vertical(state: ScrollbarState) -> Option<Self> { Self::new(state, ScrollbarAxis::Vertical) } pub fn horizontal(state: ScrollbarState) -> Option<Self> { Self::new(state, ScrollbarAxis::Horizontal) } fn new(state: ScrollbarState, kind: ScrollbarAxis) -> Option<Self> { let thumb = state.thumb_range(kind)?; Some(Self { thumb, state, kind }) }} impl Element for Scrollbar { type RequestLayoutState = (); type PrepaintState = Hitbox; fn id(&self) -> Option<ElementId> { None } fn request_layout( &mut self, _id: Option<&GlobalElementId>, window: &mut Window, cx: &mut App, ) -> (LayoutId, Self::RequestLayoutState) { let mut style = Style::default(); style.flex_grow = 1.; style.flex_shrink = 1.; if self.kind == ScrollbarAxis::Vertical { style.size.width = px(12.).into(); style.size.height = relative(1.).into(); } else { style.size.width = relative(1.).into(); style.size.height = px(12.).into(); } (window.request_layout(style, None, cx), ()) } fn prepaint( &mut self, _id: Option<&GlobalElementId>, bounds: Bounds<Pixels>, _request_layout: &mut Self::RequestLayoutState, window: &mut Window, _: &mut App, ) -> Self::PrepaintState { window.with_content_mask(Some(ContentMask { bounds }), |window| { window.insert_hitbox(bounds, false) }) } fn paint( &mut self, _id: Option<&GlobalElementId>, bounds: Bounds<Pixels>, _request_layout: &mut Self::RequestLayoutState, _prepaint: &mut Self::PrepaintState, window: &mut Window, cx: &mut App, ) { window.with_content_mask(Some(ContentMask { bounds }), |window| { let colors = cx.theme().colors(); let thumb_background = colors .surface_background .blend(colors.scrollbar_thumb_background); let is_vertical = self.kind == ScrollbarAxis::Vertical; let extra_padding = px(5.0); let padded_bounds = if is_vertical { Bounds::from_corners( bounds.origin + point(Pixels::ZERO, extra_padding), bounds.bottom_right() - point(Pixels::ZERO, extra_padding * 3), ) } else { Bounds::from_corners( bounds.origin + point(extra_padding, Pixels::ZERO), bounds.bottom_right() - point(extra_padding * 3, Pixels::ZERO), ) }; let mut thumb_bounds = if is_vertical { let thumb_offset = self.thumb.start * padded_bounds.size.height; let thumb_end = self.thumb.end * padded_bounds.size.height; let thumb_upper_left = point( padded_bounds.origin.x, padded_bounds.origin.y + thumb_offset, ); let thumb_lower_right = point( padded_bounds.origin.x + padded_bounds.size.width, padded_bounds.origin.y + thumb_end, ); Bounds::from_corners(thumb_upper_left, thumb_lower_right) } else { let thumb_offset = self.thumb.start * padded_bounds.size.width; let thumb_end = self.thumb.end * padded_bounds.size.width; let thumb_upper_left = point( padded_bounds.origin.x + thumb_offset, padded_bounds.origin.y, ); let thumb_lower_right = point( padded_bounds.origin.x + thumb_end, padded_bounds.origin.y + padded_bounds.size.height, ); Bounds::from_corners(thumb_upper_left, thumb_lower_right) }; let corners = if is_vertical { thumb_bounds.size.width /= 1.5; Corners::all(thumb_bounds.size.width / 2.0) } else { thumb_bounds.size.height /= 1.5; Corners::all(thumb_bounds.size.height / 2.0) }; window.paint_quad(quad( thumb_bounds, corners, thumb_background, Edges::default(), Hsla::transparent_black(), )); let scroll = self.state.scroll_handle.clone(); let axis = self.kind; window.on_mouse_event({ let scroll = scroll.clone(); let state = self.state.clone(); move |event: &MouseDownEvent, phase, _, _| { if !(phase.bubble() && bounds.contains(&event.position)) { return; } if thumb_bounds.contains(&event.position) { let offset = event.position.along(axis) - thumb_bounds.origin.along(axis); state.drag.set(Some(offset)); } else if let Some(ContentSize { size: item_size, .. }) = scroll.content_size() { let click_offset = { let viewport_size = padded_bounds.size.along(axis); let thumb_size = thumb_bounds.size.along(axis); let thumb_start = (event.position.along(axis) - padded_bounds.origin.along(axis) - (thumb_size / 2.)) .clamp(px(0.), viewport_size - thumb_size); let max_offset = (item_size.along(axis) - viewport_size).max(px(0.)); let percentage = if viewport_size > thumb_size { thumb_start / (viewport_size - thumb_size) } else { 0. }; -max_offset * percentage }; match axis { ScrollbarAxis::Horizontal => { scroll.set_offset(point(click_offset, scroll.offset().y)); } ScrollbarAxis::Vertical => { scroll.set_offset(point(scroll.offset().x, click_offset)); } } } } }); window.on_mouse_event({ let scroll = scroll.clone(); move |event: &ScrollWheelEvent, phase, window, _| { if phase.bubble() && bounds.contains(&event.position) { let current_offset = scroll.offset(); scroll.set_offset( current_offset + event.delta.pixel_delta(window.line_height()), ); } } }); let state = self.state.clone(); let axis = self.kind; window.on_mouse_event(move |event: &MouseMoveEvent, _, _, cx| { if let Some(drag_state) = state.drag.get().filter(|_| event.dragging()) { if let Some(ContentSize { size: item_size, .. }) = scroll.content_size() { let drag_offset = { let viewport_size = padded_bounds.size.along(axis); let thumb_size = thumb_bounds.size.along(axis); let thumb_start = (event.position.along(axis) - padded_bounds.origin.along(axis) - drag_state) .clamp(px(0.), viewport_size - thumb_size); let max_offset = (item_size.along(axis) - viewport_size).max(px(0.)); let percentage = if viewport_size > thumb_size { thumb_start / (viewport_size - thumb_size) } else { 0. }; -max_offset * percentage }; match axis { ScrollbarAxis::Horizontal => { scroll.set_offset(point(drag_offset, scroll.offset().y)); } ScrollbarAxis::Vertical => { scroll.set_offset(point(scroll.offset().x, drag_offset)); } }; if let Some(id) = state.parent_id { cx.notify(id); } } } else { state.drag.set(None); } }); let state = self.state.clone(); window.on_mouse_event(move |_event: &MouseUpEvent, phase, _, cx| { if phase.bubble() { state.drag.take(); if let Some(id) = state.parent_id { cx.notify(id); } } }); }) }} impl IntoElement for Scrollbar { type Element = Self; fn into_element(self) -> Self::Element { self }}
use std::{any::Any, cell::Cell, fmt::Debug, ops::Range, rc::Rc, sync::Arc};
use crate::{prelude::*, px, relative, IntoElement};
use gpui::{
point, quad, Along, App, Axis as ScrollbarAxis, Bounds, ContentMask, Corners, Edges, Element,
ElementId, Entity, EntityId, GlobalElementId, Hitbox, Hsla, LayoutId, MouseDownEvent,
MouseMoveEvent, MouseUpEvent, Pixels, Point, ScrollHandle, ScrollWheelEvent, Size, Style,
UniformListScrollHandle, Window,
};
pub struct Scrollbar {
thumb: Range<f32>,
state: ScrollbarState,
kind: ScrollbarAxis,
}
impl ScrollableHandle for UniformListScrollHandle {
fn content_size(&self) -> Option<ContentSize> {
Some(ContentSize {
size: self.0.borrow().last_item_size.map(|size| size.contents)?,
scroll_adjustment: None,
})
}
fn set_offset(&self, point: Point<Pixels>) {
self.0.borrow().base_handle.set_offset(point);
}
fn offset(&self) -> Point<Pixels> {
self.0.borrow().base_handle.offset()
}
fn viewport(&self) -> Bounds<Pixels> {
self.0.borrow().base_handle.bounds()
}
fn as_any(&self) -> &dyn Any {
self
}
}
impl ScrollableHandle for ScrollHandle {
fn content_size(&self) -> Option<ContentSize> {
let last_children_index = self.children_count().checked_sub(1)?;
let mut last_item = self.bounds_for_item(last_children_index)?;
let mut scroll_adjustment = None;
if last_children_index != 0 {
// todo: PO: this is slightly wrong for horizontal scrollbar, as the last item is not necessarily the longest one.
let first_item = self.bounds_for_item(0)?;
last_item.size.height += last_item.origin.y;
last_item.size.width += last_item.origin.x;
scroll_adjustment = Some(first_item.origin);
last_item.size.height -= first_item.origin.y;
last_item.size.width -= first_item.origin.x;
}
Some(ContentSize {
size: last_item.size,
scroll_adjustment,
})
}
fn set_offset(&self, point: Point<Pixels>) {
self.set_offset(point);
}
fn offset(&self) -> Point<Pixels> {
self.offset()
}
fn viewport(&self) -> Bounds<Pixels> {
self.bounds()
}
fn as_any(&self) -> &dyn Any {
self
}
}
#[derive(Debug)]
pub struct ContentSize {
pub size: Size<Pixels>,
pub scroll_adjustment: Option<Point<Pixels>>,
}
pub trait ScrollableHandle: Debug + 'static {
fn content_size(&self) -> Option<ContentSize>;
fn set_offset(&self, point: Point<Pixels>);
fn offset(&self) -> Point<Pixels>;
fn viewport(&self) -> Bounds<Pixels>;
fn as_any(&self) -> &dyn Any;
}
/// A scrollbar state that should be persisted across frames.
#[derive(Clone, Debug)]
pub struct ScrollbarState {
// If Some(), there's an active drag, offset by percentage from the origin of a thumb.
drag: Rc<Cell<Option<Pixels>>>,
parent_id: Option<EntityId>,
scroll_handle: Arc<dyn ScrollableHandle>,
}
impl ScrollbarState {
pub fn new(scroll: impl ScrollableHandle) -> Self {
Self {
drag: Default::default(),
parent_id: None,
scroll_handle: Arc::new(scroll),
}
}
/// Set a parent model which should be notified whenever this Scrollbar gets a scroll event.
pub fn parent_entity<V: 'static>(mut self, v: &Entity<V>) -> Self {
self.parent_id = Some(v.entity_id());
self
}
pub fn scroll_handle(&self) -> &Arc<dyn ScrollableHandle> {
&self.scroll_handle
}
pub fn is_dragging(&self) -> bool {
self.drag.get().is_some()
}
fn thumb_range(&self, axis: ScrollbarAxis) -> Option<Range<f32>> {
const MINIMUM_THUMB_SIZE: f32 = 25.;
let ContentSize {
size: main_dimension_size,
scroll_adjustment,
} = self.scroll_handle.content_size()?;
let content_size = main_dimension_size.along(axis).0;
let mut current_offset = self.scroll_handle.offset().along(axis).min(px(0.)).abs().0;
if let Some(adjustment) = scroll_adjustment.and_then(|adjustment| {
let adjust = adjustment.along(axis).0;
if adjust < 0.0 {
Some(adjust)
} else {
None
}
}) {
current_offset -= adjustment;
}
let viewport_size = self.scroll_handle.viewport().size.along(axis).0;
if content_size < viewport_size {
return None;
}
let visible_percentage = viewport_size / content_size;
let thumb_size = MINIMUM_THUMB_SIZE.max(viewport_size * visible_percentage);
if thumb_size > viewport_size {
return None;
}
let max_offset = content_size - viewport_size;
current_offset = current_offset.clamp(0., max_offset);
let start_offset = (current_offset / max_offset) * (viewport_size - thumb_size);
let thumb_percentage_start = start_offset / viewport_size;
let thumb_percentage_end = (start_offset + thumb_size) / viewport_size;
Some(thumb_percentage_start..thumb_percentage_end)
}
}
impl Scrollbar {
pub fn vertical(state: ScrollbarState) -> Option<Self> {
Self::new(state, ScrollbarAxis::Vertical)
}
pub fn horizontal(state: ScrollbarState) -> Option<Self> {
Self::new(state, ScrollbarAxis::Horizontal)
}
fn new(state: ScrollbarState, kind: ScrollbarAxis) -> Option<Self> {
let thumb = state.thumb_range(kind)?;
Some(Self { thumb, state, kind })
}
}
impl Element for Scrollbar {
type RequestLayoutState = ();
type PrepaintState = Hitbox;
fn id(&self) -> Option<ElementId> {
None
}
fn request_layout(
&mut self,
_id: Option<&GlobalElementId>,
window: &mut Window,
cx: &mut App,
) -> (LayoutId, Self::RequestLayoutState) {
let mut style = Style::default();
style.flex_grow = 1.;
style.flex_shrink = 1.;
if self.kind == ScrollbarAxis::Vertical {
style.size.width = px(12.).into();
style.size.height = relative(1.).into();
} else {
style.size.width = relative(1.).into();
style.size.height = px(12.).into();
}
(window.request_layout(style, None, cx), ())
}
fn prepaint(
&mut self,
_id: Option<&GlobalElementId>,
bounds: Bounds<Pixels>,
_request_layout: &mut Self::RequestLayoutState,
window: &mut Window,
_: &mut App,
) -> Self::PrepaintState {
window.with_content_mask(Some(ContentMask { bounds }), |window| {
window.insert_hitbox(bounds, false)
})
}
fn paint(
&mut self,
_id: Option<&GlobalElementId>,
bounds: Bounds<Pixels>,
_request_layout: &mut Self::RequestLayoutState,
_prepaint: &mut Self::PrepaintState,
window: &mut Window,
cx: &mut App,
) {
window.with_content_mask(Some(ContentMask { bounds }), |window| {
let colors = cx.theme().colors();
let thumb_background = colors
.surface_background
.blend(colors.scrollbar_thumb_background);
let is_vertical = self.kind == ScrollbarAxis::Vertical;
let extra_padding = px(5.0);
let padded_bounds = if is_vertical {
Bounds::from_corners(
bounds.origin + point(Pixels::ZERO, extra_padding),
bounds.bottom_right() - point(Pixels::ZERO, extra_padding * 3),
)
} else {
Bounds::from_corners(
bounds.origin + point(extra_padding, Pixels::ZERO),
bounds.bottom_right() - point(extra_padding * 3, Pixels::ZERO),
)
};
let mut thumb_bounds = if is_vertical {
let thumb_offset = self.thumb.start * padded_bounds.size.height;
let thumb_end = self.thumb.end * padded_bounds.size.height;
let thumb_upper_left = point(
padded_bounds.origin.x,
padded_bounds.origin.y + thumb_offset,
);
let thumb_lower_right = point(
padded_bounds.origin.x + padded_bounds.size.width,
padded_bounds.origin.y + thumb_end,
);
Bounds::from_corners(thumb_upper_left, thumb_lower_right)
} else {
let thumb_offset = self.thumb.start * padded_bounds.size.width;
let thumb_end = self.thumb.end * padded_bounds.size.width;
let thumb_upper_left = point(
padded_bounds.origin.x + thumb_offset,
padded_bounds.origin.y,
);
let thumb_lower_right = point(
padded_bounds.origin.x + thumb_end,
padded_bounds.origin.y + padded_bounds.size.height,
);
Bounds::from_corners(thumb_upper_left, thumb_lower_right)
};
let corners = if is_vertical {
thumb_bounds.size.width /= 1.5;
Corners::all(thumb_bounds.size.width / 2.0)
} else {
thumb_bounds.size.height /= 1.5;
Corners::all(thumb_bounds.size.height / 2.0)
};
window.paint_quad(quad(
thumb_bounds,
corners,
thumb_background,
Edges::default(),
Hsla::transparent_black(),
));
let scroll = self.state.scroll_handle.clone();
let axis = self.kind;
window.on_mouse_event({
let scroll = scroll.clone();
let state = self.state.clone();
move |event: &MouseDownEvent, phase, _, _| {
if !(phase.bubble() && bounds.contains(&event.position)) {
return;
}
if thumb_bounds.contains(&event.position) {
let offset = event.position.along(axis) - thumb_bounds.origin.along(axis);
state.drag.set(Some(offset));
} else if let Some(ContentSize {
size: item_size, ..
}) = scroll.content_size()
{
let click_offset = {
let viewport_size = padded_bounds.size.along(axis);
let thumb_size = thumb_bounds.size.along(axis);
let thumb_start = (event.position.along(axis)
- padded_bounds.origin.along(axis)
- (thumb_size / 2.))
.clamp(px(0.), viewport_size - thumb_size);
let max_offset = (item_size.along(axis) - viewport_size).max(px(0.));
let percentage = if viewport_size > thumb_size {
thumb_start / (viewport_size - thumb_size)
} else {
0.
};
-max_offset * percentage
};
match axis {
ScrollbarAxis::Horizontal => {
scroll.set_offset(point(click_offset, scroll.offset().y));
}
ScrollbarAxis::Vertical => {
scroll.set_offset(point(scroll.offset().x, click_offset));
}
}
}
}
});
window.on_mouse_event({
let scroll = scroll.clone();
move |event: &ScrollWheelEvent, phase, window, _| {
if phase.bubble() && bounds.contains(&event.position) {
let current_offset = scroll.offset();
scroll.set_offset(
current_offset + event.delta.pixel_delta(window.line_height()),
);
}
}
});
let state = self.state.clone();
let axis = self.kind;
window.on_mouse_event(move |event: &MouseMoveEvent, _, _, cx| {
if let Some(drag_state) = state.drag.get().filter(|_| event.dragging()) {
if let Some(ContentSize {
size: item_size, ..
}) = scroll.content_size()
{
let drag_offset = {
let viewport_size = padded_bounds.size.along(axis);
let thumb_size = thumb_bounds.size.along(axis);
let thumb_start = (event.position.along(axis)
- padded_bounds.origin.along(axis)
- drag_state)
.clamp(px(0.), viewport_size - thumb_size);
let max_offset = (item_size.along(axis) - viewport_size).max(px(0.));
let percentage = if viewport_size > thumb_size {
thumb_start / (viewport_size - thumb_size)
} else {
0.
};
-max_offset * percentage
};
match axis {
ScrollbarAxis::Horizontal => {
scroll.set_offset(point(drag_offset, scroll.offset().y));
}
ScrollbarAxis::Vertical => {
scroll.set_offset(point(scroll.offset().x, drag_offset));
}
};
if let Some(id) = state.parent_id {
cx.notify(id);
}
}
} else {
state.drag.set(None);
}
});
let state = self.state.clone();
window.on_mouse_event(move |_event: &MouseUpEvent, phase, _, cx| {
if phase.bubble() {
state.drag.take();
if let Some(id) = state.parent_id {
cx.notify(id);
}
}
});
})
}
}
impl IntoElement for Scrollbar {
type Element = Self;
fn into_element(self) -> Self::Element {
self
}
}