scroll.rs

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