element.rs

  1use super::{DisplayPoint, Editor, SelectAction, Snapshot};
  2use crate::time::ReplicaId;
  3use gpui::{
  4    color::Color,
  5    geometry::{
  6        rect::RectF,
  7        vector::{vec2f, Vector2F},
  8        PathBuilder,
  9    },
 10    json::{self, ToJson},
 11    text_layout::{self, TextLayoutCache},
 12    AfterLayoutContext, AppContext, Border, Element, Event, EventContext, FontCache, LayoutContext,
 13    MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext, WeakViewHandle,
 14};
 15use json::json;
 16use smallvec::SmallVec;
 17use std::{
 18    cmp::{self, Ordering},
 19    collections::{BTreeMap, HashMap},
 20    ops::Range,
 21};
 22
 23pub struct EditorElement {
 24    view: WeakViewHandle<Editor>,
 25}
 26
 27impl EditorElement {
 28    pub fn new(view: WeakViewHandle<Editor>) -> Self {
 29        Self { view }
 30    }
 31
 32    fn view<'a>(&self, cx: &'a AppContext) -> &'a Editor {
 33        self.view.upgrade(cx).unwrap().read(cx)
 34    }
 35
 36    fn update_view<F, T>(&self, cx: &mut MutableAppContext, f: F) -> T
 37    where
 38        F: FnOnce(&mut Editor, &mut ViewContext<Editor>) -> T,
 39    {
 40        self.view.upgrade(cx).unwrap().update(cx, f)
 41    }
 42
 43    fn snapshot(&self, cx: &mut MutableAppContext) -> Snapshot {
 44        self.update_view(cx, |view, cx| view.snapshot(cx))
 45    }
 46
 47    fn mouse_down(
 48        &self,
 49        position: Vector2F,
 50        cmd: bool,
 51        layout: &mut LayoutState,
 52        paint: &mut PaintState,
 53        cx: &mut EventContext,
 54    ) -> bool {
 55        if paint.text_bounds.contains_point(position) {
 56            let snapshot = self.snapshot(cx.app);
 57            let position = paint.point_for_position(&snapshot, layout, position);
 58            cx.dispatch_action("buffer:select", SelectAction::Begin { position, add: cmd });
 59            true
 60        } else {
 61            false
 62        }
 63    }
 64
 65    fn mouse_up(&self, _position: Vector2F, cx: &mut EventContext) -> bool {
 66        if self.view(cx.app.as_ref()).is_selecting() {
 67            cx.dispatch_action("buffer:select", SelectAction::End);
 68            true
 69        } else {
 70            false
 71        }
 72    }
 73
 74    fn mouse_dragged(
 75        &self,
 76        position: Vector2F,
 77        layout: &mut LayoutState,
 78        paint: &mut PaintState,
 79        cx: &mut EventContext,
 80    ) -> bool {
 81        let view = self.view(cx.app.as_ref());
 82
 83        if view.is_selecting() {
 84            let rect = paint.text_bounds;
 85            let mut scroll_delta = Vector2F::zero();
 86
 87            let vertical_margin = layout.line_height.min(rect.height() / 3.0);
 88            let top = rect.origin_y() + vertical_margin;
 89            let bottom = rect.lower_left().y() - vertical_margin;
 90            if position.y() < top {
 91                scroll_delta.set_y(-scale_vertical_mouse_autoscroll_delta(top - position.y()))
 92            }
 93            if position.y() > bottom {
 94                scroll_delta.set_y(scale_vertical_mouse_autoscroll_delta(position.y() - bottom))
 95            }
 96
 97            let horizontal_margin = layout.line_height.min(rect.width() / 3.0);
 98            let left = rect.origin_x() + horizontal_margin;
 99            let right = rect.upper_right().x() - horizontal_margin;
100            if position.x() < left {
101                scroll_delta.set_x(-scale_horizontal_mouse_autoscroll_delta(
102                    left - position.x(),
103                ))
104            }
105            if position.x() > right {
106                scroll_delta.set_x(scale_horizontal_mouse_autoscroll_delta(
107                    position.x() - right,
108                ))
109            }
110
111            let font_cache = cx.font_cache.clone();
112            let text_layout_cache = cx.text_layout_cache.clone();
113            let snapshot = self.snapshot(cx.app);
114            let position = paint.point_for_position(&snapshot, layout, position);
115
116            cx.dispatch_action(
117                "buffer:select",
118                SelectAction::Update {
119                    position,
120                    scroll_position: (snapshot.scroll_position() + scroll_delta).clamp(
121                        Vector2F::zero(),
122                        layout.scroll_max(&font_cache, &text_layout_cache),
123                    ),
124                },
125            );
126            true
127        } else {
128            false
129        }
130    }
131
132    fn key_down(&self, chars: &str, cx: &mut EventContext) -> bool {
133        let view = self.view.upgrade(cx.app).unwrap();
134
135        if view.is_focused(cx.app) {
136            if chars.is_empty() {
137                false
138            } else {
139                if chars.chars().any(|c| c.is_control()) {
140                    false
141                } else {
142                    cx.dispatch_action("buffer:insert", chars.to_string());
143                    true
144                }
145            }
146        } else {
147            false
148        }
149    }
150
151    fn scroll(
152        &self,
153        position: Vector2F,
154        mut delta: Vector2F,
155        precise: bool,
156        layout: &mut LayoutState,
157        paint: &mut PaintState,
158        cx: &mut EventContext,
159    ) -> bool {
160        if !paint.bounds.contains_point(position) {
161            return false;
162        }
163
164        let snapshot = self.snapshot(cx.app);
165        let font_cache = &cx.font_cache;
166        let layout_cache = &cx.text_layout_cache;
167        let max_glyph_width = layout.em_width;
168        if !precise {
169            delta *= vec2f(max_glyph_width, layout.line_height);
170        }
171
172        let scroll_position = snapshot.scroll_position();
173        let x = (scroll_position.x() * max_glyph_width - delta.x()) / max_glyph_width;
174        let y = (scroll_position.y() * layout.line_height - delta.y()) / layout.line_height;
175        let scroll_position = vec2f(x, y).clamp(
176            Vector2F::zero(),
177            layout.scroll_max(font_cache, layout_cache),
178        );
179
180        cx.dispatch_action("buffer:scroll", scroll_position);
181
182        true
183    }
184
185    fn paint_background(
186        &self,
187        gutter_bounds: RectF,
188        text_bounds: RectF,
189        layout: &LayoutState,
190        cx: &mut PaintContext,
191    ) {
192        let bounds = gutter_bounds.union_rect(text_bounds);
193        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
194        let editor = self.view(cx.app);
195        let settings = editor.settings.borrow();
196        let theme = &settings.theme;
197        cx.scene.push_quad(Quad {
198            bounds: gutter_bounds,
199            background: Some(theme.editor.gutter_background),
200            border: Border::new(0., Color::transparent_black()),
201            corner_radius: 0.,
202        });
203        cx.scene.push_quad(Quad {
204            bounds: text_bounds,
205            background: Some(theme.editor.background),
206            border: Border::new(0., Color::transparent_black()),
207            corner_radius: 0.,
208        });
209
210        if !editor.single_line {
211            let mut active_rows = layout.active_rows.iter().peekable();
212            while let Some((start_row, contains_non_empty_selection)) = active_rows.next() {
213                let mut end_row = *start_row;
214                while active_rows.peek().map_or(false, |r| {
215                    *r.0 == end_row + 1 && r.1 == contains_non_empty_selection
216                }) {
217                    active_rows.next().unwrap();
218                    end_row += 1;
219                }
220
221                if !contains_non_empty_selection {
222                    let origin = vec2f(
223                        bounds.origin_x(),
224                        bounds.origin_y() + (layout.line_height * *start_row as f32) - scroll_top,
225                    );
226                    let size = vec2f(
227                        bounds.width(),
228                        layout.line_height * (end_row - start_row + 1) as f32,
229                    );
230                    cx.scene.push_quad(Quad {
231                        bounds: RectF::new(origin, size),
232                        background: Some(theme.editor.active_line_background),
233                        border: Border::default(),
234                        corner_radius: 0.,
235                    });
236                }
237            }
238        }
239    }
240
241    fn paint_gutter(&mut self, rect: RectF, layout: &LayoutState, cx: &mut PaintContext) {
242        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
243        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
244            if let Some(line) = line {
245                let line_origin = rect.origin()
246                    + vec2f(
247                        rect.width() - line.width() - layout.gutter_padding,
248                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
249                    );
250                line.paint(
251                    line_origin,
252                    RectF::new(vec2f(0., 0.), vec2f(line.width(), layout.line_height)),
253                    cx,
254                );
255            }
256        }
257    }
258
259    fn paint_text(&mut self, bounds: RectF, layout: &LayoutState, cx: &mut PaintContext) {
260        let view = self.view(cx.app);
261        let settings = self.view(cx.app).settings.borrow();
262        let theme = &settings.theme.editor;
263        let scroll_position = layout.snapshot.scroll_position();
264        let start_row = scroll_position.y() as u32;
265        let scroll_top = scroll_position.y() * layout.line_height;
266        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
267        let max_glyph_width = layout.em_width;
268        let scroll_left = scroll_position.x() * max_glyph_width;
269
270        cx.scene.push_layer(Some(bounds));
271
272        // Draw selections
273        let corner_radius = 2.5;
274        let mut cursors = SmallVec::<[Cursor; 32]>::new();
275
276        let content_origin = bounds.origin() + layout.text_offset;
277
278        for (replica_id, selections) in &layout.selections {
279            let replica_theme = theme.replicas[*replica_id as usize % theme.replicas.len()];
280
281            for selection in selections {
282                if selection.start != selection.end {
283                    let range_start = cmp::min(selection.start, selection.end);
284                    let range_end = cmp::max(selection.start, selection.end);
285                    let row_range = if range_end.column() == 0 {
286                        cmp::max(range_start.row(), start_row)..cmp::min(range_end.row(), end_row)
287                    } else {
288                        cmp::max(range_start.row(), start_row)
289                            ..cmp::min(range_end.row() + 1, end_row)
290                    };
291
292                    let selection = Selection {
293                        color: replica_theme.selection,
294                        line_height: layout.line_height,
295                        start_y: content_origin.y() + row_range.start as f32 * layout.line_height
296                            - scroll_top,
297                        lines: row_range
298                            .into_iter()
299                            .map(|row| {
300                                let line_layout = &layout.line_layouts[(row - start_row) as usize];
301                                SelectionLine {
302                                    start_x: if row == range_start.row() {
303                                        content_origin.x()
304                                            + line_layout.x_for_index(range_start.column() as usize)
305                                            - scroll_left
306                                    } else {
307                                        content_origin.x() - scroll_left
308                                    },
309                                    end_x: if row == range_end.row() {
310                                        content_origin.x()
311                                            + line_layout.x_for_index(range_end.column() as usize)
312                                            - scroll_left
313                                    } else {
314                                        content_origin.x()
315                                            + line_layout.width()
316                                            + corner_radius * 2.0
317                                            - scroll_left
318                                    },
319                                }
320                            })
321                            .collect(),
322                    };
323
324                    selection.paint(bounds, cx.scene);
325                }
326
327                if view.cursors_visible() {
328                    let cursor_position = selection.end;
329                    if (start_row..end_row).contains(&cursor_position.row()) {
330                        let cursor_row_layout =
331                            &layout.line_layouts[(selection.end.row() - start_row) as usize];
332                        let x = cursor_row_layout.x_for_index(selection.end.column() as usize)
333                            - scroll_left;
334                        let y = selection.end.row() as f32 * layout.line_height - scroll_top;
335                        cursors.push(Cursor {
336                            color: replica_theme.cursor,
337                            origin: content_origin + vec2f(x, y),
338                            line_height: layout.line_height,
339                        });
340                    }
341                }
342            }
343        }
344
345        // Draw glyphs
346        for (ix, line) in layout.line_layouts.iter().enumerate() {
347            let row = start_row + ix as u32;
348            line.paint(
349                content_origin + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
350                RectF::new(
351                    vec2f(scroll_left, 0.),
352                    vec2f(bounds.width(), layout.line_height),
353                ),
354                cx,
355            );
356        }
357
358        cx.scene.push_layer(Some(bounds));
359        for cursor in cursors {
360            cursor.paint(cx);
361        }
362        cx.scene.pop_layer();
363
364        cx.scene.pop_layer();
365    }
366}
367
368impl Element for EditorElement {
369    type LayoutState = Option<LayoutState>;
370    type PaintState = Option<PaintState>;
371
372    fn layout(
373        &mut self,
374        constraint: SizeConstraint,
375        cx: &mut LayoutContext,
376    ) -> (Vector2F, Self::LayoutState) {
377        let mut size = constraint.max;
378        if size.x().is_infinite() {
379            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
380        }
381
382        let font_cache = &cx.font_cache;
383        let layout_cache = &cx.text_layout_cache;
384        let snapshot = self.snapshot(cx.app);
385        let line_height = snapshot.line_height(font_cache);
386
387        let gutter_padding;
388        let gutter_width;
389        if snapshot.gutter_visible {
390            gutter_padding = snapshot.em_width(cx.font_cache);
391            match snapshot.max_line_number_width(cx.font_cache, cx.text_layout_cache) {
392                Err(error) => {
393                    log::error!("error computing max line number width: {}", error);
394                    return (size, None);
395                }
396                Ok(width) => gutter_width = width + gutter_padding * 2.0,
397            }
398        } else {
399            gutter_padding = 0.0;
400            gutter_width = 0.0
401        };
402
403        let text_width = size.x() - gutter_width;
404        let text_offset = vec2f(-snapshot.font_descent(cx.font_cache), 0.);
405        let em_width = snapshot.em_width(font_cache);
406        let overscroll = vec2f(em_width, 0.);
407        let wrap_width = text_width - text_offset.x() - overscroll.x() - em_width;
408        let snapshot = self.update_view(cx.app, |view, cx| {
409            if view.set_wrap_width(wrap_width, cx) {
410                view.snapshot(cx)
411            } else {
412                snapshot
413            }
414        });
415        if size.y().is_infinite() {
416            size.set_y((snapshot.max_point().row() + 1) as f32 * line_height);
417        }
418        let gutter_size = vec2f(gutter_width, size.y());
419        let text_size = vec2f(text_width, size.y());
420
421        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
422            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
423            let snapshot = view.snapshot(cx);
424            (autoscroll_horizontally, snapshot)
425        });
426
427        let scroll_position = snapshot.scroll_position();
428        let start_row = scroll_position.y() as u32;
429        let scroll_top = scroll_position.y() * line_height;
430        let end_row = ((scroll_top + size.y()) / line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
431
432        let mut selections = HashMap::new();
433        let mut active_rows = BTreeMap::new();
434        self.update_view(cx.app, |view, cx| {
435            let replica_id = view.replica_id(cx);
436            for selection_set_id in view.active_selection_sets(cx).collect::<Vec<_>>() {
437                let mut set = Vec::new();
438                for selection in view.selections_in_range(
439                    selection_set_id,
440                    DisplayPoint::new(start_row, 0)..DisplayPoint::new(end_row, 0),
441                    cx,
442                ) {
443                    set.push(selection.clone());
444                    if selection_set_id.replica_id == replica_id {
445                        let is_empty = selection.start == selection.end;
446                        let mut selection_start;
447                        let mut selection_end;
448                        if selection.start < selection.end {
449                            selection_start = selection.start;
450                            selection_end = selection.end;
451                        } else {
452                            selection_start = selection.end;
453                            selection_end = selection.start;
454                        };
455                        selection_start = snapshot.prev_row_boundary(selection_start).0;
456                        selection_end = snapshot.next_row_boundary(selection_end).0;
457                        for row in cmp::max(selection_start.row(), start_row)
458                            ..=cmp::min(selection_end.row(), end_row)
459                        {
460                            let contains_non_empty_selection =
461                                active_rows.entry(row).or_insert(!is_empty);
462                            *contains_non_empty_selection |= !is_empty;
463                        }
464                    }
465                }
466
467                selections.insert(selection_set_id.replica_id, set);
468            }
469        });
470
471        let line_number_layouts = if snapshot.gutter_visible {
472            let settings = self
473                .view
474                .upgrade(cx.app)
475                .unwrap()
476                .read(cx.app)
477                .settings
478                .borrow();
479            match snapshot.layout_line_numbers(
480                start_row..end_row,
481                &active_rows,
482                cx.font_cache,
483                cx.text_layout_cache,
484                &settings.theme,
485            ) {
486                Err(error) => {
487                    log::error!("error laying out line numbers: {}", error);
488                    return (size, None);
489                }
490                Ok(layouts) => layouts,
491            }
492        } else {
493            Vec::new()
494        };
495
496        let mut max_visible_line_width = 0.0;
497        let line_layouts = match snapshot.layout_lines(start_row..end_row, font_cache, layout_cache)
498        {
499            Err(error) => {
500                log::error!("error laying out lines: {}", error);
501                return (size, None);
502            }
503            Ok(layouts) => {
504                for line in &layouts {
505                    if line.width() > max_visible_line_width {
506                        max_visible_line_width = line.width();
507                    }
508                }
509
510                layouts
511            }
512        };
513
514        let mut layout = LayoutState {
515            size,
516            gutter_size,
517            gutter_padding,
518            text_size,
519            overscroll,
520            text_offset,
521            snapshot,
522            active_rows,
523            line_layouts,
524            line_number_layouts,
525            line_height,
526            em_width,
527            selections,
528            max_visible_line_width,
529        };
530
531        self.update_view(cx.app, |view, cx| {
532            let clamped = view.clamp_scroll_left(layout.scroll_max(font_cache, layout_cache).x());
533            let autoscrolled;
534            if autoscroll_horizontally {
535                autoscrolled = view.autoscroll_horizontally(
536                    start_row,
537                    layout.text_size.x(),
538                    layout.scroll_width(font_cache, layout_cache),
539                    layout.snapshot.em_width(font_cache),
540                    &layout.line_layouts,
541                    cx,
542                );
543            } else {
544                autoscrolled = false;
545            }
546
547            if clamped || autoscrolled {
548                layout.snapshot = view.snapshot(cx);
549            }
550        });
551
552        (size, Some(layout))
553    }
554
555    fn after_layout(&mut self, _: Vector2F, _: &mut Self::LayoutState, _: &mut AfterLayoutContext) {
556    }
557
558    fn paint(
559        &mut self,
560        bounds: RectF,
561        layout: &mut Self::LayoutState,
562        cx: &mut PaintContext,
563    ) -> Self::PaintState {
564        if let Some(layout) = layout {
565            cx.scene.push_layer(Some(bounds));
566
567            let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
568            let text_bounds = RectF::new(
569                bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
570                layout.text_size,
571            );
572
573            self.paint_background(gutter_bounds, text_bounds, layout, cx);
574            if layout.gutter_size.x() > 0. {
575                self.paint_gutter(gutter_bounds, layout, cx);
576            }
577            self.paint_text(text_bounds, layout, cx);
578
579            cx.scene.pop_layer();
580
581            Some(PaintState {
582                bounds,
583                text_bounds,
584            })
585        } else {
586            None
587        }
588    }
589
590    fn dispatch_event(
591        &mut self,
592        event: &Event,
593        _: RectF,
594        layout: &mut Self::LayoutState,
595        paint: &mut Self::PaintState,
596        cx: &mut EventContext,
597    ) -> bool {
598        if let (Some(layout), Some(paint)) = (layout, paint) {
599            match event {
600                Event::LeftMouseDown { position, cmd } => {
601                    self.mouse_down(*position, *cmd, layout, paint, cx)
602                }
603                Event::LeftMouseUp { position } => self.mouse_up(*position, cx),
604                Event::LeftMouseDragged { position } => {
605                    self.mouse_dragged(*position, layout, paint, cx)
606                }
607                Event::ScrollWheel {
608                    position,
609                    delta,
610                    precise,
611                } => self.scroll(*position, *delta, *precise, layout, paint, cx),
612                Event::KeyDown { chars, .. } => self.key_down(chars, cx),
613                _ => false,
614            }
615        } else {
616            false
617        }
618    }
619
620    fn debug(
621        &self,
622        bounds: RectF,
623        _: &Self::LayoutState,
624        _: &Self::PaintState,
625        _: &gpui::DebugContext,
626    ) -> json::Value {
627        json!({
628            "type": "BufferElement",
629            "bounds": bounds.to_json()
630        })
631    }
632}
633
634pub struct LayoutState {
635    size: Vector2F,
636    gutter_size: Vector2F,
637    gutter_padding: f32,
638    text_size: Vector2F,
639    snapshot: Snapshot,
640    active_rows: BTreeMap<u32, bool>,
641    line_layouts: Vec<text_layout::Line>,
642    line_number_layouts: Vec<Option<text_layout::Line>>,
643    line_height: f32,
644    em_width: f32,
645    selections: HashMap<ReplicaId, Vec<Range<DisplayPoint>>>,
646    overscroll: Vector2F,
647    text_offset: Vector2F,
648    max_visible_line_width: f32,
649}
650
651impl LayoutState {
652    fn scroll_width(&self, font_cache: &FontCache, layout_cache: &TextLayoutCache) -> f32 {
653        let row = self.snapshot.longest_row();
654        let longest_line_width = self
655            .snapshot
656            .layout_line(row, font_cache, layout_cache)
657            .unwrap()
658            .width();
659        longest_line_width.max(self.max_visible_line_width) + self.overscroll.x()
660    }
661
662    fn scroll_max(&self, font_cache: &FontCache, layout_cache: &TextLayoutCache) -> Vector2F {
663        let text_width = self.text_size.x();
664        let scroll_width = self.scroll_width(font_cache, layout_cache);
665        let em_width = self.snapshot.em_width(font_cache);
666        let max_row = self.snapshot.max_point().row();
667
668        vec2f(
669            ((scroll_width - text_width) / em_width).max(0.0),
670            max_row.saturating_sub(1) as f32,
671        )
672    }
673}
674
675pub struct PaintState {
676    bounds: RectF,
677    text_bounds: RectF,
678}
679
680impl PaintState {
681    fn point_for_position(
682        &self,
683        snapshot: &Snapshot,
684        layout: &LayoutState,
685        position: Vector2F,
686    ) -> DisplayPoint {
687        let scroll_position = snapshot.scroll_position();
688        let position = position - self.text_bounds.origin();
689        let y = position.y().max(0.0).min(layout.size.y());
690        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
691        let row = cmp::min(row, snapshot.max_point().row());
692        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
693        let x = position.x() + (scroll_position.x() * layout.em_width);
694
695        let column = if x >= 0.0 {
696            line.index_for_x(x)
697                .map(|ix| ix as u32)
698                .unwrap_or(snapshot.line_len(row))
699        } else {
700            0
701        };
702
703        DisplayPoint::new(row, column)
704    }
705}
706
707struct Cursor {
708    origin: Vector2F,
709    line_height: f32,
710    color: Color,
711}
712
713impl Cursor {
714    fn paint(&self, cx: &mut PaintContext) {
715        cx.scene.push_quad(Quad {
716            bounds: RectF::new(self.origin, vec2f(2.0, self.line_height)),
717            background: Some(self.color),
718            border: Border::new(0., Color::black()),
719            corner_radius: 0.,
720        });
721    }
722}
723
724#[derive(Debug)]
725struct Selection {
726    start_y: f32,
727    line_height: f32,
728    lines: Vec<SelectionLine>,
729    color: Color,
730}
731
732#[derive(Debug)]
733struct SelectionLine {
734    start_x: f32,
735    end_x: f32,
736}
737
738impl Selection {
739    fn paint(&self, bounds: RectF, scene: &mut Scene) {
740        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
741            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
742            self.paint_lines(
743                self.start_y + self.line_height,
744                &self.lines[1..],
745                bounds,
746                scene,
747            );
748        } else {
749            self.paint_lines(self.start_y, &self.lines, bounds, scene);
750        }
751    }
752
753    fn paint_lines(&self, start_y: f32, lines: &[SelectionLine], bounds: RectF, scene: &mut Scene) {
754        if lines.is_empty() {
755            return;
756        }
757
758        let mut path = PathBuilder::new();
759        let corner_radius = 0.15 * self.line_height;
760        let first_line = lines.first().unwrap();
761        let last_line = lines.last().unwrap();
762
763        let first_top_left = vec2f(first_line.start_x, start_y);
764        let first_top_right = vec2f(first_line.end_x, start_y);
765
766        let curve_height = vec2f(0., corner_radius);
767        let curve_width = |start_x: f32, end_x: f32| {
768            let max = (end_x - start_x) / 2.;
769            let width = if max < corner_radius {
770                max
771            } else {
772                corner_radius
773            };
774
775            vec2f(width, 0.)
776        };
777
778        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
779        path.reset(first_top_right - top_curve_width);
780        path.curve_to(first_top_right + curve_height, first_top_right);
781
782        let mut iter = lines.iter().enumerate().peekable();
783        while let Some((ix, line)) = iter.next() {
784            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
785
786            if let Some((_, next_line)) = iter.peek() {
787                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
788
789                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
790                    Ordering::Equal => {
791                        path.line_to(bottom_right);
792                    }
793                    Ordering::Less => {
794                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
795                        path.line_to(bottom_right - curve_height);
796                        path.curve_to(bottom_right - curve_width, bottom_right);
797                        path.line_to(next_top_right + curve_width);
798                        path.curve_to(next_top_right + curve_height, next_top_right);
799                    }
800                    Ordering::Greater => {
801                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
802                        path.line_to(bottom_right - curve_height);
803                        path.curve_to(bottom_right + curve_width, bottom_right);
804                        path.line_to(next_top_right - curve_width);
805                        path.curve_to(next_top_right + curve_height, next_top_right);
806                    }
807                }
808            } else {
809                let curve_width = curve_width(line.start_x, line.end_x);
810                path.line_to(bottom_right - curve_height);
811                path.curve_to(bottom_right - curve_width, bottom_right);
812
813                let bottom_left = vec2f(line.start_x, bottom_right.y());
814                path.line_to(bottom_left + curve_width);
815                path.curve_to(bottom_left - curve_height, bottom_left);
816            }
817        }
818
819        if first_line.start_x > last_line.start_x {
820            let curve_width = curve_width(last_line.start_x, first_line.start_x);
821            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
822            path.line_to(second_top_left + curve_height);
823            path.curve_to(second_top_left + curve_width, second_top_left);
824            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
825            path.line_to(first_bottom_left - curve_width);
826            path.curve_to(first_bottom_left - curve_height, first_bottom_left);
827        }
828
829        path.line_to(first_top_left + curve_height);
830        path.curve_to(first_top_left + top_curve_width, first_top_left);
831        path.line_to(first_top_right - top_curve_width);
832
833        scene.push_path(path.build(self.color, Some(bounds)));
834    }
835}
836
837fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
838    delta.powf(1.5) / 100.0
839}
840
841fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
842    delta.powf(1.2) / 300.0
843}