1use std::{cmp, f32};
2
3use gpui::{px, Pixels, ViewContext};
4use language::Point;
5
6use crate::{display_map::ToDisplayPoint, Editor, EditorMode, LineWithInvisibles};
7
8#[derive(PartialEq, Eq, Clone, Copy)]
9pub enum Autoscroll {
10 Next,
11 Strategy(AutoscrollStrategy),
12}
13
14impl Autoscroll {
15 /// scrolls the minimal amount to (try) and fit all cursors onscreen
16 pub fn fit() -> Self {
17 Self::Strategy(AutoscrollStrategy::Fit)
18 }
19
20 /// scrolls the minimal amount to fit the newest cursor
21 pub fn newest() -> Self {
22 Self::Strategy(AutoscrollStrategy::Newest)
23 }
24
25 /// scrolls so the newest cursor is vertically centered
26 pub fn center() -> Self {
27 Self::Strategy(AutoscrollStrategy::Center)
28 }
29
30 /// scrolls so the neweset cursor is near the top
31 /// (offset by vertical_scroll_margin)
32 pub fn focused() -> Self {
33 Self::Strategy(AutoscrollStrategy::Focused)
34 }
35 /// Scrolls so that the newest cursor is roughly an n-th line from the top.
36 pub fn top_relative(n: usize) -> Self {
37 Self::Strategy(AutoscrollStrategy::TopRelative(n))
38 }
39}
40
41#[derive(PartialEq, Eq, Default, Clone, Copy)]
42pub enum AutoscrollStrategy {
43 Fit,
44 Newest,
45 #[default]
46 Center,
47 Focused,
48 Top,
49 Bottom,
50 TopRelative(usize),
51}
52
53impl AutoscrollStrategy {
54 fn next(&self) -> Self {
55 match self {
56 AutoscrollStrategy::Center => AutoscrollStrategy::Top,
57 AutoscrollStrategy::Top => AutoscrollStrategy::Bottom,
58 _ => AutoscrollStrategy::Center,
59 }
60 }
61}
62
63impl Editor {
64 pub fn autoscroll_vertically(
65 &mut self,
66 viewport_height: Pixels,
67 line_height: Pixels,
68 cx: &mut ViewContext<Editor>,
69 ) -> bool {
70 let visible_lines = viewport_height / line_height;
71 let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
72 let mut scroll_position = self.scroll_manager.scroll_position(&display_map);
73 let max_scroll_top = if matches!(self.mode, EditorMode::AutoHeight { .. }) {
74 (display_map.max_point().row() as f32 - visible_lines + 1.).max(0.)
75 } else {
76 display_map.max_point().row() as f32
77 };
78 if scroll_position.y > max_scroll_top {
79 scroll_position.y = max_scroll_top;
80 self.set_scroll_position(scroll_position, cx);
81 }
82
83 let Some((autoscroll, local)) = self.scroll_manager.autoscroll_request.take() else {
84 return false;
85 };
86
87 let mut target_top;
88 let mut target_bottom;
89 if let Some(first_highlighted_row) = &self.highlighted_display_rows(cx).first_entry() {
90 target_top = *first_highlighted_row.key() as f32;
91 target_bottom = target_top + 1.;
92 } else {
93 let selections = self.selections.all::<Point>(cx);
94 target_top = selections
95 .first()
96 .unwrap()
97 .head()
98 .to_display_point(&display_map)
99 .row() as f32;
100 target_bottom = selections
101 .last()
102 .unwrap()
103 .head()
104 .to_display_point(&display_map)
105 .row() as f32
106 + 1.0;
107
108 // If the selections can't all fit on screen, scroll to the newest.
109 if autoscroll == Autoscroll::newest()
110 || autoscroll == Autoscroll::fit() && target_bottom - target_top > visible_lines
111 {
112 let newest_selection_top = selections
113 .iter()
114 .max_by_key(|s| s.id)
115 .unwrap()
116 .head()
117 .to_display_point(&display_map)
118 .row() as f32;
119 target_top = newest_selection_top;
120 target_bottom = newest_selection_top + 1.;
121 }
122 }
123
124 let margin = if matches!(self.mode, EditorMode::AutoHeight { .. }) {
125 0.
126 } else {
127 ((visible_lines - (target_bottom - target_top)) / 2.0).floor()
128 };
129
130 let strategy = match autoscroll {
131 Autoscroll::Strategy(strategy) => strategy,
132 Autoscroll::Next => {
133 let last_autoscroll = &self.scroll_manager.last_autoscroll;
134 if let Some(last_autoscroll) = last_autoscroll {
135 if self.scroll_manager.anchor.offset == last_autoscroll.0
136 && target_top == last_autoscroll.1
137 && target_bottom == last_autoscroll.2
138 {
139 last_autoscroll.3.next()
140 } else {
141 AutoscrollStrategy::default()
142 }
143 } else {
144 AutoscrollStrategy::default()
145 }
146 }
147 };
148
149 match strategy {
150 AutoscrollStrategy::Fit | AutoscrollStrategy::Newest => {
151 let margin = margin.min(self.scroll_manager.vertical_scroll_margin);
152 let target_top = (target_top - margin).max(0.0);
153 let target_bottom = target_bottom + margin;
154 let start_row = scroll_position.y;
155 let end_row = start_row + visible_lines;
156
157 let needs_scroll_up = target_top < start_row;
158 let needs_scroll_down = target_bottom >= end_row;
159
160 if needs_scroll_up && !needs_scroll_down {
161 scroll_position.y = target_top;
162 self.set_scroll_position_internal(scroll_position, local, true, cx);
163 }
164 if !needs_scroll_up && needs_scroll_down {
165 scroll_position.y = target_bottom - visible_lines;
166 self.set_scroll_position_internal(scroll_position, local, true, cx);
167 }
168 }
169 AutoscrollStrategy::Center => {
170 scroll_position.y = (target_top - margin).max(0.0);
171 self.set_scroll_position_internal(scroll_position, local, true, cx);
172 }
173 AutoscrollStrategy::Focused => {
174 scroll_position.y =
175 (target_top - self.scroll_manager.vertical_scroll_margin).max(0.0);
176 self.set_scroll_position_internal(scroll_position, local, true, cx);
177 }
178 AutoscrollStrategy::Top => {
179 scroll_position.y = (target_top).max(0.0);
180 self.set_scroll_position_internal(scroll_position, local, true, cx);
181 }
182 AutoscrollStrategy::Bottom => {
183 scroll_position.y = (target_bottom - visible_lines).max(0.0);
184 self.set_scroll_position_internal(scroll_position, local, true, cx);
185 }
186 AutoscrollStrategy::TopRelative(lines) => {
187 scroll_position.y = target_top - lines as f32;
188 self.set_scroll_position_internal(scroll_position, local, true, cx);
189 }
190 }
191
192 self.scroll_manager.last_autoscroll = Some((
193 self.scroll_manager.anchor.offset,
194 target_top,
195 target_bottom,
196 strategy,
197 ));
198
199 true
200 }
201
202 pub(crate) fn autoscroll_horizontally(
203 &mut self,
204 start_row: u32,
205 viewport_width: Pixels,
206 scroll_width: Pixels,
207 max_glyph_width: Pixels,
208 layouts: &[LineWithInvisibles],
209 cx: &mut ViewContext<Self>,
210 ) -> bool {
211 let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
212 let selections = self.selections.all::<Point>(cx);
213
214 let mut target_left;
215 let mut target_right;
216
217 if self.highlighted_rows.is_empty() {
218 target_left = px(f32::INFINITY);
219 target_right = px(0.);
220 for selection in selections {
221 let head = selection.head().to_display_point(&display_map);
222 if head.row() >= start_row && head.row() < start_row + layouts.len() as u32 {
223 let start_column = head.column().saturating_sub(3);
224 let end_column = cmp::min(display_map.line_len(head.row()), head.column() + 3);
225 target_left = target_left.min(
226 layouts[(head.row() - start_row) as usize]
227 .line
228 .x_for_index(start_column as usize),
229 );
230 target_right = target_right.max(
231 layouts[(head.row() - start_row) as usize]
232 .line
233 .x_for_index(end_column as usize)
234 + max_glyph_width,
235 );
236 }
237 }
238 } else {
239 target_left = px(0.);
240 target_right = px(0.);
241 }
242
243 target_right = target_right.min(scroll_width);
244
245 if target_right - target_left > viewport_width {
246 return false;
247 }
248
249 let scroll_left = self.scroll_manager.anchor.offset.x * max_glyph_width;
250 let scroll_right = scroll_left + viewport_width;
251
252 if target_left < scroll_left {
253 self.scroll_manager.anchor.offset.x = target_left / max_glyph_width;
254 true
255 } else if target_right > scroll_right {
256 self.scroll_manager.anchor.offset.x = (target_right - viewport_width) / max_glyph_width;
257 true
258 } else {
259 false
260 }
261 }
262
263 pub fn request_autoscroll(&mut self, autoscroll: Autoscroll, cx: &mut ViewContext<Self>) {
264 self.scroll_manager.autoscroll_request = Some((autoscroll, true));
265 cx.notify();
266 }
267
268 pub(crate) fn request_autoscroll_remotely(
269 &mut self,
270 autoscroll: Autoscroll,
271 cx: &mut ViewContext<Self>,
272 ) {
273 self.scroll_manager.autoscroll_request = Some((autoscroll, false));
274 cx.notify();
275 }
276}