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 margin = if matches!(self.mode, EditorMode::AutoHeight { .. }) {
190 0.
191 } else {
192 ((visible_lines - (target_bottom - target_top)) / 2.0).floor()
193 };
194
195 let strategy = match autoscroll {
196 Autoscroll::Strategy(strategy, _) => strategy,
197 Autoscroll::Next => {
198 let last_autoscroll = &self.scroll_manager.last_autoscroll;
199 if let Some(last_autoscroll) = last_autoscroll {
200 if self.scroll_manager.anchor.offset == last_autoscroll.0
201 && target_top == last_autoscroll.1
202 && target_bottom == last_autoscroll.2
203 {
204 last_autoscroll.3.next()
205 } else {
206 AutoscrollStrategy::default()
207 }
208 } else {
209 AutoscrollStrategy::default()
210 }
211 }
212 };
213 if let Autoscroll::Strategy(_, Some(anchor)) = autoscroll {
214 target_top = anchor.to_display_point(&display_map).row().as_f64();
215 target_bottom = target_top + 1.;
216 }
217
218 let was_autoscrolled = match strategy {
219 AutoscrollStrategy::Fit | AutoscrollStrategy::Newest => {
220 let margin = margin.min(self.scroll_manager.vertical_scroll_margin);
221 let target_top = (target_top - margin).max(0.0);
222 let target_bottom = target_bottom + margin;
223 let start_row = scroll_position.y;
224 let end_row = start_row + visible_lines;
225
226 let needs_scroll_up = target_top < start_row;
227 let needs_scroll_down = target_bottom >= end_row;
228
229 if needs_scroll_up && !needs_scroll_down {
230 scroll_position.y = target_top;
231 } else if !needs_scroll_up && needs_scroll_down {
232 scroll_position.y = target_bottom - visible_lines;
233 }
234
235 if needs_scroll_up ^ needs_scroll_down {
236 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
237 } else {
238 WasScrolled(false)
239 }
240 }
241 AutoscrollStrategy::Center => {
242 scroll_position.y = (target_top - margin).max(0.0);
243 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
244 }
245 AutoscrollStrategy::Focused => {
246 let margin = margin.min(self.scroll_manager.vertical_scroll_margin);
247 scroll_position.y = (target_top - margin).max(0.0);
248 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
249 }
250 AutoscrollStrategy::Top => {
251 scroll_position.y = (target_top).max(0.0);
252 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
253 }
254 AutoscrollStrategy::Bottom => {
255 scroll_position.y = (target_bottom - visible_lines).max(0.0);
256 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
257 }
258 AutoscrollStrategy::TopRelative(lines) => {
259 scroll_position.y = target_top - lines as ScrollOffset;
260 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
261 }
262 AutoscrollStrategy::BottomRelative(lines) => {
263 scroll_position.y = target_bottom + lines as ScrollOffset;
264 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
265 }
266 };
267
268 self.scroll_manager.last_autoscroll = Some((
269 self.scroll_manager.anchor.offset,
270 target_top,
271 target_bottom,
272 strategy,
273 ));
274
275 let was_scrolled = WasScrolled(editor_was_scrolled.0 || was_autoscrolled.0);
276 (NeedsHorizontalAutoscroll(true), was_scrolled)
277 }
278
279 pub(crate) fn autoscroll_horizontally(
280 &mut self,
281 start_row: DisplayRow,
282 viewport_width: Pixels,
283 scroll_width: Pixels,
284 em_advance: Pixels,
285 layouts: &[LineWithInvisibles],
286 autoscroll_request: Option<(Autoscroll, bool)>,
287 window: &mut Window,
288 cx: &mut Context<Self>,
289 ) -> Option<gpui::Point<ScrollOffset>> {
290 let (_, local) = autoscroll_request?;
291 let em_advance = ScrollOffset::from(em_advance);
292 let viewport_width = ScrollOffset::from(viewport_width);
293 let scroll_width = ScrollOffset::from(scroll_width);
294
295 let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
296 let selections = self.selections.all::<Point>(&display_map);
297 let mut scroll_position = self.scroll_manager.scroll_position(&display_map);
298
299 let mut target_left;
300 let mut target_right: f64;
301
302 if self
303 .highlighted_display_row_for_autoscroll(&display_map)
304 .is_none()
305 {
306 target_left = f64::INFINITY;
307 target_right = 0.;
308 for selection in selections {
309 let head = selection.head().to_display_point(&display_map);
310 if head.row() >= start_row
311 && head.row() < DisplayRow(start_row.0 + layouts.len() as u32)
312 {
313 let start_column = head.column();
314 let end_column = cmp::min(display_map.line_len(head.row()), head.column());
315 target_left = target_left.min(ScrollOffset::from(
316 layouts[head.row().minus(start_row) as usize]
317 .x_for_index(start_column as usize)
318 + self.gutter_dimensions.margin,
319 ));
320 target_right = target_right.max(
321 ScrollOffset::from(
322 layouts[head.row().minus(start_row) as usize]
323 .x_for_index(end_column as usize),
324 ) + em_advance,
325 );
326 }
327 }
328 } else {
329 target_left = 0.;
330 target_right = 0.;
331 }
332
333 target_right = target_right.min(scroll_width);
334
335 if target_right - target_left > viewport_width {
336 return None;
337 }
338
339 let scroll_left = self.scroll_manager.anchor.offset.x * em_advance;
340 let scroll_right = scroll_left + viewport_width;
341
342 let was_scrolled = if target_left < scroll_left {
343 scroll_position.x = target_left / em_advance;
344 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
345 } else if target_right > scroll_right {
346 scroll_position.x = (target_right - viewport_width) / em_advance;
347 self.set_scroll_position_internal(scroll_position, local, true, window, cx)
348 } else {
349 WasScrolled(false)
350 };
351
352 if was_scrolled.0 {
353 Some(scroll_position)
354 } else {
355 None
356 }
357 }
358
359 pub fn request_autoscroll(&mut self, autoscroll: Autoscroll, cx: &mut Context<Self>) {
360 self.scroll_manager.autoscroll_request = Some((autoscroll, true));
361 cx.notify();
362 }
363
364 pub(crate) fn request_autoscroll_remotely(
365 &mut self,
366 autoscroll: Autoscroll,
367 cx: &mut Context<Self>,
368 ) {
369 self.scroll_manager.autoscroll_request = Some((autoscroll, false));
370 cx.notify();
371 }
372}