scroll.rs

  1mod actions;
  2pub(crate) mod autoscroll;
  3pub(crate) mod scroll_amount;
  4
  5use crate::editor_settings::{ScrollBeyondLastLine, ScrollbarAxes};
  6use crate::{
  7    display_map::{DisplaySnapshot, ToDisplayPoint},
  8    hover_popover::hide_hover,
  9    persistence::DB,
 10    Anchor, DisplayPoint, DisplayRow, Editor, EditorEvent, EditorMode, EditorSettings,
 11    InlayHintRefreshReason, MultiBufferSnapshot, RowExt, ToPoint,
 12};
 13pub use autoscroll::{Autoscroll, AutoscrollStrategy};
 14use core::fmt::Debug;
 15use gpui::{point, px, Along, App, Axis, Context, Global, Pixels, Task, Window};
 16use language::{Bias, Point};
 17pub use scroll_amount::ScrollAmount;
 18use settings::Settings;
 19use std::{
 20    cmp::Ordering,
 21    time::{Duration, Instant},
 22};
 23use util::ResultExt;
 24use workspace::{ItemId, WorkspaceId};
 25
 26pub const SCROLL_EVENT_SEPARATION: Duration = Duration::from_millis(28);
 27const SCROLLBAR_SHOW_INTERVAL: Duration = Duration::from_secs(1);
 28
 29#[derive(Default)]
 30pub struct ScrollbarAutoHide(pub bool);
 31
 32impl Global for ScrollbarAutoHide {}
 33
 34#[derive(Clone, Copy, Debug, PartialEq)]
 35pub struct ScrollAnchor {
 36    pub offset: gpui::Point<f32>,
 37    pub anchor: Anchor,
 38}
 39
 40impl ScrollAnchor {
 41    fn new() -> Self {
 42        Self {
 43            offset: gpui::Point::default(),
 44            anchor: Anchor::min(),
 45        }
 46    }
 47
 48    pub fn scroll_position(&self, snapshot: &DisplaySnapshot) -> gpui::Point<f32> {
 49        let mut scroll_position = self.offset;
 50        if self.anchor == Anchor::min() {
 51            scroll_position.y = 0.;
 52        } else {
 53            let scroll_top = self.anchor.to_display_point(snapshot).row().as_f32();
 54            scroll_position.y += scroll_top;
 55        }
 56        scroll_position
 57    }
 58
 59    pub fn top_row(&self, buffer: &MultiBufferSnapshot) -> u32 {
 60        self.anchor.to_point(buffer).row
 61    }
 62}
 63
 64#[derive(Debug, Clone)]
 65pub struct AxisPair<T: Clone> {
 66    pub vertical: T,
 67    pub horizontal: T,
 68}
 69
 70pub fn axis_pair<T: Clone>(horizontal: T, vertical: T) -> AxisPair<T> {
 71    AxisPair {
 72        vertical,
 73        horizontal,
 74    }
 75}
 76
 77impl<T: Clone> AxisPair<T> {
 78    pub fn as_xy(&self) -> (&T, &T) {
 79        (&self.horizontal, &self.vertical)
 80    }
 81}
 82
 83impl<T: Clone> Along for AxisPair<T> {
 84    type Unit = T;
 85
 86    fn along(&self, axis: gpui::Axis) -> Self::Unit {
 87        match axis {
 88            gpui::Axis::Horizontal => self.horizontal.clone(),
 89            gpui::Axis::Vertical => self.vertical.clone(),
 90        }
 91    }
 92
 93    fn apply_along(&self, axis: gpui::Axis, f: impl FnOnce(Self::Unit) -> Self::Unit) -> Self {
 94        match axis {
 95            gpui::Axis::Horizontal => Self {
 96                horizontal: f(self.horizontal.clone()),
 97                vertical: self.vertical.clone(),
 98            },
 99            gpui::Axis::Vertical => Self {
100                horizontal: self.horizontal.clone(),
101                vertical: f(self.vertical.clone()),
102            },
103        }
104    }
105}
106
107impl From<ScrollbarAxes> for AxisPair<bool> {
108    fn from(value: ScrollbarAxes) -> Self {
109        axis_pair(value.horizontal, value.vertical)
110    }
111}
112
113#[derive(Clone, Copy, Debug)]
114pub struct OngoingScroll {
115    last_event: Instant,
116    axis: Option<Axis>,
117}
118
119impl OngoingScroll {
120    fn new() -> Self {
121        Self {
122            last_event: Instant::now() - SCROLL_EVENT_SEPARATION,
123            axis: None,
124        }
125    }
126
127    pub fn filter(&self, delta: &mut gpui::Point<Pixels>) -> Option<Axis> {
128        const UNLOCK_PERCENT: f32 = 1.9;
129        const UNLOCK_LOWER_BOUND: Pixels = px(6.);
130        let mut axis = self.axis;
131
132        let x = delta.x.abs();
133        let y = delta.y.abs();
134        let duration = Instant::now().duration_since(self.last_event);
135        if duration > SCROLL_EVENT_SEPARATION {
136            //New ongoing scroll will start, determine axis
137            axis = if x <= y {
138                Some(Axis::Vertical)
139            } else {
140                Some(Axis::Horizontal)
141            };
142        } else if x.max(y) >= UNLOCK_LOWER_BOUND {
143            //Check if the current ongoing will need to unlock
144            match axis {
145                Some(Axis::Vertical) => {
146                    if x > y && x >= y * UNLOCK_PERCENT {
147                        axis = None;
148                    }
149                }
150
151                Some(Axis::Horizontal) => {
152                    if y > x && y >= x * UNLOCK_PERCENT {
153                        axis = None;
154                    }
155                }
156
157                None => {}
158            }
159        }
160
161        match axis {
162            Some(Axis::Vertical) => {
163                *delta = point(px(0.), delta.y);
164            }
165            Some(Axis::Horizontal) => {
166                *delta = point(delta.x, px(0.));
167            }
168            None => {}
169        }
170
171        axis
172    }
173}
174
175pub struct ScrollManager {
176    pub(crate) vertical_scroll_margin: f32,
177    anchor: ScrollAnchor,
178    ongoing: OngoingScroll,
179    autoscroll_request: Option<(Autoscroll, bool)>,
180    last_autoscroll: Option<(gpui::Point<f32>, f32, f32, AutoscrollStrategy)>,
181    show_scrollbars: bool,
182    hide_scrollbar_task: Option<Task<()>>,
183    dragging_scrollbar: AxisPair<bool>,
184    visible_line_count: Option<f32>,
185    forbid_vertical_scroll: bool,
186}
187
188impl ScrollManager {
189    pub fn new(cx: &mut App) -> Self {
190        ScrollManager {
191            vertical_scroll_margin: EditorSettings::get_global(cx).vertical_scroll_margin,
192            anchor: ScrollAnchor::new(),
193            ongoing: OngoingScroll::new(),
194            autoscroll_request: None,
195            show_scrollbars: true,
196            hide_scrollbar_task: None,
197            dragging_scrollbar: axis_pair(false, false),
198            last_autoscroll: None,
199            visible_line_count: None,
200            forbid_vertical_scroll: false,
201        }
202    }
203
204    pub fn clone_state(&mut self, other: &Self) {
205        self.anchor = other.anchor;
206        self.ongoing = other.ongoing;
207    }
208
209    pub fn anchor(&self) -> ScrollAnchor {
210        self.anchor
211    }
212
213    pub fn ongoing_scroll(&self) -> OngoingScroll {
214        self.ongoing
215    }
216
217    pub fn update_ongoing_scroll(&mut self, axis: Option<Axis>) {
218        self.ongoing.last_event = Instant::now();
219        self.ongoing.axis = axis;
220    }
221
222    pub fn scroll_position(&self, snapshot: &DisplaySnapshot) -> gpui::Point<f32> {
223        self.anchor.scroll_position(snapshot)
224    }
225
226    #[allow(clippy::too_many_arguments)]
227    fn set_scroll_position(
228        &mut self,
229        scroll_position: gpui::Point<f32>,
230        map: &DisplaySnapshot,
231        local: bool,
232        autoscroll: bool,
233        workspace_id: Option<WorkspaceId>,
234        window: &mut Window,
235        cx: &mut Context<Editor>,
236    ) {
237        if self.forbid_vertical_scroll {
238            return;
239        }
240        let (new_anchor, top_row) = if scroll_position.y <= 0. {
241            (
242                ScrollAnchor {
243                    anchor: Anchor::min(),
244                    offset: scroll_position.max(&gpui::Point::default()),
245                },
246                0,
247            )
248        } else {
249            let scroll_top = scroll_position.y;
250            let scroll_top = match EditorSettings::get_global(cx).scroll_beyond_last_line {
251                ScrollBeyondLastLine::OnePage => scroll_top,
252                ScrollBeyondLastLine::Off => {
253                    if let Some(height_in_lines) = self.visible_line_count {
254                        let max_row = map.max_point().row().0 as f32;
255                        scroll_top.min(max_row - height_in_lines + 1.).max(0.)
256                    } else {
257                        scroll_top
258                    }
259                }
260                ScrollBeyondLastLine::VerticalScrollMargin => {
261                    if let Some(height_in_lines) = self.visible_line_count {
262                        let max_row = map.max_point().row().0 as f32;
263                        scroll_top
264                            .min(max_row - height_in_lines + 1. + self.vertical_scroll_margin)
265                            .max(0.)
266                    } else {
267                        scroll_top
268                    }
269                }
270            };
271
272            let scroll_top_buffer_point =
273                DisplayPoint::new(DisplayRow(scroll_top as u32), 0).to_point(map);
274            let top_anchor = map
275                .buffer_snapshot
276                .anchor_at(scroll_top_buffer_point, Bias::Right);
277
278            (
279                ScrollAnchor {
280                    anchor: top_anchor,
281                    offset: point(
282                        scroll_position.x.max(0.),
283                        scroll_top - top_anchor.to_display_point(map).row().as_f32(),
284                    ),
285                },
286                scroll_top_buffer_point.row,
287            )
288        };
289
290        self.set_anchor(
291            new_anchor,
292            top_row,
293            local,
294            autoscroll,
295            workspace_id,
296            window,
297            cx,
298        );
299    }
300
301    #[allow(clippy::too_many_arguments)]
302    fn set_anchor(
303        &mut self,
304        anchor: ScrollAnchor,
305        top_row: u32,
306        local: bool,
307        autoscroll: bool,
308        workspace_id: Option<WorkspaceId>,
309        window: &mut Window,
310        cx: &mut Context<Editor>,
311    ) {
312        if self.forbid_vertical_scroll {
313            return;
314        }
315        self.anchor = anchor;
316        cx.emit(EditorEvent::ScrollPositionChanged { local, autoscroll });
317        self.show_scrollbar(window, cx);
318        self.autoscroll_request.take();
319        if let Some(workspace_id) = workspace_id {
320            let item_id = cx.entity().entity_id().as_u64() as ItemId;
321
322            cx.foreground_executor()
323                .spawn(async move {
324                    DB.save_scroll_position(
325                        item_id,
326                        workspace_id,
327                        top_row,
328                        anchor.offset.x,
329                        anchor.offset.y,
330                    )
331                    .await
332                    .log_err()
333                })
334                .detach()
335        }
336        cx.notify();
337    }
338
339    pub fn show_scrollbar(&mut self, window: &mut Window, cx: &mut Context<Editor>) {
340        if !self.show_scrollbars {
341            self.show_scrollbars = true;
342            cx.notify();
343        }
344
345        if cx.default_global::<ScrollbarAutoHide>().0 {
346            self.hide_scrollbar_task = Some(cx.spawn_in(window, |editor, mut cx| async move {
347                cx.background_executor()
348                    .timer(SCROLLBAR_SHOW_INTERVAL)
349                    .await;
350                editor
351                    .update(&mut cx, |editor, cx| {
352                        editor.scroll_manager.show_scrollbars = false;
353                        cx.notify();
354                    })
355                    .log_err();
356            }));
357        } else {
358            self.hide_scrollbar_task = None;
359        }
360    }
361
362    pub fn scrollbars_visible(&self) -> bool {
363        self.show_scrollbars
364    }
365
366    pub fn autoscroll_request(&self) -> Option<Autoscroll> {
367        self.autoscroll_request.map(|(autoscroll, _)| autoscroll)
368    }
369
370    pub fn is_dragging_scrollbar(&self, axis: Axis) -> bool {
371        self.dragging_scrollbar.along(axis)
372    }
373
374    pub fn set_is_dragging_scrollbar(
375        &mut self,
376        axis: Axis,
377        dragging: bool,
378        cx: &mut Context<Editor>,
379    ) {
380        self.dragging_scrollbar = self.dragging_scrollbar.apply_along(axis, |_| dragging);
381        cx.notify();
382    }
383
384    pub fn clamp_scroll_left(&mut self, max: f32) -> bool {
385        if max < self.anchor.offset.x {
386            self.anchor.offset.x = max;
387            true
388        } else {
389            false
390        }
391    }
392
393    pub fn set_forbid_vertical_scroll(&mut self, forbid: bool) {
394        self.forbid_vertical_scroll = forbid;
395    }
396
397    pub fn forbid_vertical_scroll(&self) -> bool {
398        self.forbid_vertical_scroll
399    }
400}
401
402impl Editor {
403    pub fn vertical_scroll_margin(&self) -> usize {
404        self.scroll_manager.vertical_scroll_margin as usize
405    }
406
407    pub fn set_vertical_scroll_margin(&mut self, margin_rows: usize, cx: &mut Context<Self>) {
408        self.scroll_manager.vertical_scroll_margin = margin_rows as f32;
409        cx.notify();
410    }
411
412    pub fn visible_line_count(&self) -> Option<f32> {
413        self.scroll_manager.visible_line_count
414    }
415
416    pub fn visible_row_count(&self) -> Option<u32> {
417        self.visible_line_count()
418            .map(|line_count| line_count as u32 - 1)
419    }
420
421    pub(crate) fn set_visible_line_count(
422        &mut self,
423        lines: f32,
424        window: &mut Window,
425        cx: &mut Context<Self>,
426    ) {
427        let opened_first_time = self.scroll_manager.visible_line_count.is_none();
428        self.scroll_manager.visible_line_count = Some(lines);
429        if opened_first_time {
430            cx.spawn_in(window, |editor, mut cx| async move {
431                editor
432                    .update(&mut cx, |editor, cx| {
433                        editor.refresh_inlay_hints(InlayHintRefreshReason::NewLinesShown, cx)
434                    })
435                    .ok()
436            })
437            .detach()
438        }
439    }
440
441    pub fn apply_scroll_delta(
442        &mut self,
443        scroll_delta: gpui::Point<f32>,
444        window: &mut Window,
445        cx: &mut Context<Self>,
446    ) {
447        if self.scroll_manager.forbid_vertical_scroll {
448            return;
449        }
450        let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
451        let position = self.scroll_manager.anchor.scroll_position(&display_map) + scroll_delta;
452        self.set_scroll_position_taking_display_map(position, true, false, display_map, window, cx);
453    }
454
455    pub fn set_scroll_position(
456        &mut self,
457        scroll_position: gpui::Point<f32>,
458        window: &mut Window,
459        cx: &mut Context<Self>,
460    ) {
461        if self.scroll_manager.forbid_vertical_scroll {
462            return;
463        }
464        self.set_scroll_position_internal(scroll_position, true, false, window, cx);
465    }
466
467    pub(crate) fn set_scroll_position_internal(
468        &mut self,
469        scroll_position: gpui::Point<f32>,
470        local: bool,
471        autoscroll: bool,
472        window: &mut Window,
473        cx: &mut Context<Self>,
474    ) {
475        let map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
476        self.set_scroll_position_taking_display_map(
477            scroll_position,
478            local,
479            autoscroll,
480            map,
481            window,
482            cx,
483        );
484    }
485
486    fn set_scroll_position_taking_display_map(
487        &mut self,
488        scroll_position: gpui::Point<f32>,
489        local: bool,
490        autoscroll: bool,
491        display_map: DisplaySnapshot,
492        window: &mut Window,
493        cx: &mut Context<Self>,
494    ) {
495        hide_hover(self, cx);
496        let workspace_id = self.workspace.as_ref().and_then(|workspace| workspace.1);
497
498        self.edit_prediction_preview
499            .set_previous_scroll_position(None);
500
501        self.scroll_manager.set_scroll_position(
502            scroll_position,
503            &display_map,
504            local,
505            autoscroll,
506            workspace_id,
507            window,
508            cx,
509        );
510
511        self.refresh_inlay_hints(InlayHintRefreshReason::NewLinesShown, cx);
512    }
513
514    pub fn scroll_position(&self, cx: &mut Context<Self>) -> gpui::Point<f32> {
515        let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
516        self.scroll_manager.anchor.scroll_position(&display_map)
517    }
518
519    pub fn set_scroll_anchor(
520        &mut self,
521        scroll_anchor: ScrollAnchor,
522        window: &mut Window,
523        cx: &mut Context<Self>,
524    ) {
525        hide_hover(self, cx);
526        let workspace_id = self.workspace.as_ref().and_then(|workspace| workspace.1);
527        let top_row = scroll_anchor
528            .anchor
529            .to_point(&self.buffer().read(cx).snapshot(cx))
530            .row;
531        self.scroll_manager.set_anchor(
532            scroll_anchor,
533            top_row,
534            true,
535            false,
536            workspace_id,
537            window,
538            cx,
539        );
540    }
541
542    pub(crate) fn set_scroll_anchor_remote(
543        &mut self,
544        scroll_anchor: ScrollAnchor,
545        window: &mut Window,
546        cx: &mut Context<Self>,
547    ) {
548        hide_hover(self, cx);
549        let workspace_id = self.workspace.as_ref().and_then(|workspace| workspace.1);
550        let snapshot = &self.buffer().read(cx).snapshot(cx);
551        if !scroll_anchor.anchor.is_valid(snapshot) {
552            log::warn!("Invalid scroll anchor: {:?}", scroll_anchor);
553            return;
554        }
555        let top_row = scroll_anchor.anchor.to_point(snapshot).row;
556        self.scroll_manager.set_anchor(
557            scroll_anchor,
558            top_row,
559            false,
560            false,
561            workspace_id,
562            window,
563            cx,
564        );
565    }
566
567    pub fn scroll_screen(
568        &mut self,
569        amount: &ScrollAmount,
570        window: &mut Window,
571        cx: &mut Context<Self>,
572    ) {
573        if matches!(self.mode, EditorMode::SingleLine { .. }) {
574            cx.propagate();
575            return;
576        }
577
578        if self.take_rename(true, window, cx).is_some() {
579            return;
580        }
581
582        let cur_position = self.scroll_position(cx);
583        let Some(visible_line_count) = self.visible_line_count() else {
584            return;
585        };
586        let new_pos = cur_position + point(0., amount.lines(visible_line_count));
587        self.set_scroll_position(new_pos, window, cx);
588    }
589
590    /// Returns an ordering. The newest selection is:
591    ///     Ordering::Equal => on screen
592    ///     Ordering::Less => above the screen
593    ///     Ordering::Greater => below the screen
594    pub fn newest_selection_on_screen(&self, cx: &mut App) -> Ordering {
595        let snapshot = self.display_map.update(cx, |map, cx| map.snapshot(cx));
596        let newest_head = self
597            .selections
598            .newest_anchor()
599            .head()
600            .to_display_point(&snapshot);
601        let screen_top = self
602            .scroll_manager
603            .anchor
604            .anchor
605            .to_display_point(&snapshot);
606
607        if screen_top > newest_head {
608            return Ordering::Less;
609        }
610
611        if let Some(visible_lines) = self.visible_line_count() {
612            if newest_head.row() <= DisplayRow(screen_top.row().0 + visible_lines as u32) {
613                return Ordering::Equal;
614            }
615        }
616
617        Ordering::Greater
618    }
619
620    pub fn read_scroll_position_from_db(
621        &mut self,
622        item_id: u64,
623        workspace_id: WorkspaceId,
624        window: &mut Window,
625        cx: &mut Context<Editor>,
626    ) {
627        let scroll_position = DB.get_scroll_position(item_id, workspace_id);
628        if let Ok(Some((top_row, x, y))) = scroll_position {
629            let top_anchor = self
630                .buffer()
631                .read(cx)
632                .snapshot(cx)
633                .anchor_at(Point::new(top_row, 0), Bias::Left);
634            let scroll_anchor = ScrollAnchor {
635                offset: gpui::Point::new(x, y),
636                anchor: top_anchor,
637            };
638            self.set_scroll_anchor(scroll_anchor, window, cx);
639        }
640    }
641}