1use crate::{
2 DisplayRow, Editor, EditorMode, LineWithInvisibles, RowExt, SelectionEffects,
3 display_map::ToDisplayPoint,
4 scroll::{ScrollOffset, WasScrolled},
5};
6use gpui::{Bounds, Context, Pixels, Window};
7use language::Point;
8use multi_buffer::Anchor;
9use std::cmp;
10
11#[derive(Debug, PartialEq, Eq, Clone, Copy)]
12pub enum Autoscroll {
13 Next,
14 Strategy(AutoscrollStrategy, Option<Anchor>),
15}
16
17impl Autoscroll {
18 /// scrolls the minimal amount to (try) and fit all cursors onscreen
19 pub fn fit() -> Self {
20 Self::Strategy(AutoscrollStrategy::Fit, None)
21 }
22
23 /// scrolls the minimal amount to fit the newest cursor
24 pub fn newest() -> Self {
25 Self::Strategy(AutoscrollStrategy::Newest, None)
26 }
27
28 /// scrolls so the newest cursor is vertically centered
29 pub fn center() -> Self {
30 Self::Strategy(AutoscrollStrategy::Center, None)
31 }
32
33 /// scrolls so the newest cursor is near the top
34 /// (offset by vertical_scroll_margin)
35 pub fn focused() -> Self {
36 Self::Strategy(AutoscrollStrategy::Focused, None)
37 }
38
39 /// Scrolls so that the newest cursor is roughly an n-th line from the top.
40 pub fn top_relative(n: usize) -> Self {
41 Self::Strategy(AutoscrollStrategy::TopRelative(n), None)
42 }
43
44 /// Scrolls so that the newest cursor is at the top.
45 pub fn top() -> Self {
46 Self::Strategy(AutoscrollStrategy::Top, None)
47 }
48
49 /// Scrolls so that the newest cursor is roughly an n-th line from the bottom.
50 pub fn bottom_relative(n: usize) -> Self {
51 Self::Strategy(AutoscrollStrategy::BottomRelative(n), None)
52 }
53
54 /// Scrolls so that the newest cursor is at the bottom.
55 pub fn bottom() -> Self {
56 Self::Strategy(AutoscrollStrategy::Bottom, None)
57 }
58
59 /// Applies a given auto-scroll strategy to a given anchor instead of a cursor.
60 /// E.G: Autoscroll::center().for_anchor(...) results in the anchor being at the center of the screen.
61 pub fn for_anchor(self, anchor: Anchor) -> Self {
62 match self {
63 Autoscroll::Next => self,
64 Autoscroll::Strategy(autoscroll_strategy, _) => {
65 Self::Strategy(autoscroll_strategy, Some(anchor))
66 }
67 }
68 }
69}
70
71impl Into<SelectionEffects> for Option<Autoscroll> {
72 fn into(self) -> SelectionEffects {
73 match self {
74 Some(autoscroll) => SelectionEffects::scroll(autoscroll),
75 None => SelectionEffects::no_scroll(),
76 }
77 }
78}
79
80#[derive(Debug, PartialEq, Eq, Default, Clone, Copy)]
81pub enum AutoscrollStrategy {
82 Fit,
83 Newest,
84 #[default]
85 Center,
86 Focused,
87 Top,
88 Bottom,
89 TopRelative(usize),
90 BottomRelative(usize),
91}
92
93impl AutoscrollStrategy {
94 fn next(&self) -> Self {
95 match self {
96 AutoscrollStrategy::Center => AutoscrollStrategy::Top,
97 AutoscrollStrategy::Top => AutoscrollStrategy::Bottom,
98 _ => AutoscrollStrategy::Center,
99 }
100 }
101}
102
103pub(crate) struct NeedsHorizontalAutoscroll(pub(crate) bool);
104
105impl Editor {
106 pub(crate) fn autoscroll_vertically(
107 &mut self,
108 bounds: Bounds<Pixels>,
109 line_height: Pixels,
110 max_scroll_top: ScrollOffset,
111 autoscroll_request: Option<(Autoscroll, bool)>,
112 window: &mut Window,
113 cx: &mut Context<Editor>,
114 ) -> (NeedsHorizontalAutoscroll, WasScrolled) {
115 let viewport_height = bounds.size.height;
116 let visible_lines = ScrollOffset::from(viewport_height / line_height);
117 let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
118 let mut scroll_position = self.scroll_manager.scroll_position(&display_map);
119 let original_y = scroll_position.y;
120 if let Some(last_bounds) = self.expect_bounds_change.take()
121 && scroll_position.y != 0.
122 {
123 scroll_position.y +=
124 ScrollOffset::from((bounds.top() - last_bounds.top()) / line_height);
125 if scroll_position.y < 0. {
126 scroll_position.y = 0.;
127 }
128 }
129 if scroll_position.y > max_scroll_top {
130 scroll_position.y = max_scroll_top;
131 }
132
133 let editor_was_scrolled = if original_y != scroll_position.y {
134 self.set_scroll_position(scroll_position, window, cx)
135 } else {
136 WasScrolled(false)
137 };
138
139 let Some((autoscroll, local)) = autoscroll_request else {
140 return (NeedsHorizontalAutoscroll(false), editor_was_scrolled);
141 };
142
143 let mut target_top;
144 let mut target_bottom;
145 if let Some(first_highlighted_row) =
146 self.highlighted_display_row_for_autoscroll(&display_map)
147 {
148 target_top = first_highlighted_row.as_f64();
149 target_bottom = target_top + 1.;
150 } else {
151 let selections = self.selections.all::<Point>(&display_map);
152
153 target_top = selections
154 .first()
155 .unwrap()
156 .head()
157 .to_display_point(&display_map)
158 .row()
159 .as_f64();
160 target_bottom = selections
161 .last()
162 .unwrap()
163 .head()
164 .to_display_point(&display_map)
165 .row()
166 .next_row()
167 .as_f64();
168
169 let selections_fit = target_bottom - target_top <= visible_lines;
170 if matches!(
171 autoscroll,
172 Autoscroll::Strategy(AutoscrollStrategy::Newest, _)
173 ) || (matches!(autoscroll, Autoscroll::Strategy(AutoscrollStrategy::Fit, _))
174 && !selections_fit)
175 {
176 let newest_selection_top = selections
177 .iter()
178 .max_by_key(|s| s.id)
179 .unwrap()
180 .head()
181 .to_display_point(&display_map)
182 .row()
183 .as_f64();
184 target_top = newest_selection_top;
185 target_bottom = newest_selection_top + 1.;
186 }
187 }
188
189 let visible_sticky_headers = self.scroll_manager.sticky_header_line_count();
190
191 let margin = if matches!(self.mode, EditorMode::AutoHeight { .. }) {
192 0.
193 } else {
194 ((visible_lines - (target_bottom - target_top)) / 2.0).floor()
195 };
196
197 let strategy = match autoscroll {
198 Autoscroll::Strategy(strategy, _) => strategy,
199 Autoscroll::Next => self
200 .scroll_manager
201 .last_autoscroll
202 .as_ref()
203 .filter(|(offset, last_target_top, last_target_bottom, _)| {
204 self.scroll_manager.anchor.offset == *offset
205 && target_top == *last_target_top
206 && target_bottom == *last_target_bottom
207 })
208 .map(|(_, _, _, strategy)| strategy.next())
209 .unwrap_or_default(),
210 };
211 if let Autoscroll::Strategy(_, Some(anchor)) = autoscroll {
212 target_top = anchor.to_display_point(&display_map).row().as_f64();
213 target_bottom = target_top + 1.;
214 }
215
216 let was_autoscrolled = match strategy {
217 AutoscrollStrategy::Fit | AutoscrollStrategy::Newest => {
218 let margin = margin.min(self.scroll_manager.vertical_scroll_margin);
219 let target_top = (target_top - margin - visible_sticky_headers as f64).max(0.0);
220 let target_bottom = target_bottom + margin;
221 let start_row = scroll_position.y;
222 let end_row = start_row + visible_lines;
223
224 let needs_scroll_up = target_top < start_row;
225 let needs_scroll_down = target_bottom >= end_row;
226
227 if needs_scroll_up && !needs_scroll_down {
228 scroll_position.y = target_top;
229 } else if !needs_scroll_up && needs_scroll_down {
230 scroll_position.y = target_bottom - visible_lines;
231 }
232
233 if needs_scroll_up ^ needs_scroll_down {
234 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
235 } else {
236 WasScrolled(false)
237 }
238 }
239 AutoscrollStrategy::Center => {
240 scroll_position.y = (target_top - margin).max(0.0);
241 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
242 }
243 AutoscrollStrategy::Focused => {
244 let margin = margin.min(self.scroll_manager.vertical_scroll_margin);
245 scroll_position.y = (target_top - margin).max(0.0);
246 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
247 }
248 AutoscrollStrategy::Top => {
249 scroll_position.y = (target_top).max(0.0);
250 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
251 }
252 AutoscrollStrategy::Bottom => {
253 scroll_position.y = (target_bottom - visible_lines).max(0.0);
254 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
255 }
256 AutoscrollStrategy::TopRelative(lines) => {
257 scroll_position.y = target_top - lines as ScrollOffset;
258 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
259 }
260 AutoscrollStrategy::BottomRelative(lines) => {
261 scroll_position.y = target_bottom + lines as ScrollOffset;
262 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
263 }
264 };
265
266 self.scroll_manager.last_autoscroll = Some((
267 self.scroll_manager.anchor.offset,
268 target_top,
269 target_bottom,
270 strategy,
271 ));
272
273 let was_scrolled = WasScrolled(editor_was_scrolled.0 || was_autoscrolled.0);
274 (NeedsHorizontalAutoscroll(true), was_scrolled)
275 }
276
277 pub(crate) fn autoscroll_horizontally(
278 &mut self,
279 start_row: DisplayRow,
280 viewport_width: Pixels,
281 scroll_width: Pixels,
282 em_advance: Pixels,
283 layouts: &[LineWithInvisibles],
284 autoscroll_request: Option<(Autoscroll, bool)>,
285 window: &mut Window,
286 cx: &mut Context<Self>,
287 ) -> Option<gpui::Point<ScrollOffset>> {
288 let (_, local) = autoscroll_request?;
289 let em_advance = ScrollOffset::from(em_advance);
290 let viewport_width = ScrollOffset::from(viewport_width);
291 let scroll_width = ScrollOffset::from(scroll_width);
292
293 let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
294 let selections = self.selections.all::<Point>(&display_map);
295 let mut scroll_position = self.scroll_manager.scroll_position(&display_map);
296
297 let mut target_left;
298 let mut target_right: f64;
299
300 if self
301 .highlighted_display_row_for_autoscroll(&display_map)
302 .is_none()
303 {
304 target_left = f64::INFINITY;
305 target_right = 0.;
306 for selection in selections {
307 let head = selection.head().to_display_point(&display_map);
308 if head.row() >= start_row
309 && head.row() < DisplayRow(start_row.0 + layouts.len() as u32)
310 {
311 let start_column = head.column();
312 let end_column = cmp::min(display_map.line_len(head.row()), head.column());
313 target_left = target_left.min(ScrollOffset::from(
314 layouts[head.row().minus(start_row) as usize]
315 .x_for_index(start_column as usize)
316 + self.gutter_dimensions.margin,
317 ));
318 target_right = target_right.max(
319 ScrollOffset::from(
320 layouts[head.row().minus(start_row) as usize]
321 .x_for_index(end_column as usize),
322 ) + em_advance,
323 );
324 }
325 }
326 } else {
327 target_left = 0.;
328 target_right = 0.;
329 }
330
331 target_right = target_right.min(scroll_width);
332
333 if target_right - target_left > viewport_width {
334 return None;
335 }
336
337 let scroll_left = self.scroll_manager.anchor.offset.x * em_advance;
338 let scroll_right = scroll_left + viewport_width;
339
340 let was_scrolled = if target_left < scroll_left {
341 scroll_position.x = target_left / em_advance;
342 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
343 } else if target_right > scroll_right {
344 scroll_position.x = (target_right - viewport_width) / em_advance;
345 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
346 } else {
347 WasScrolled(false)
348 };
349
350 if was_scrolled.0 {
351 Some(scroll_position)
352 } else {
353 None
354 }
355 }
356
357 pub fn request_autoscroll(&mut self, autoscroll: Autoscroll, cx: &mut Context<Self>) {
358 self.scroll_manager.autoscroll_request = Some((autoscroll, true));
359 cx.notify();
360 }
361
362 pub(crate) fn request_autoscroll_remotely(
363 &mut self,
364 autoscroll: Autoscroll,
365 cx: &mut Context<Self>,
366 ) {
367 self.scroll_manager.autoscroll_request = Some((autoscroll, false));
368 cx.notify();
369 }
370}