element.rs

   1use super::{
   2    display_map::{BlockContext, ToDisplayPoint},
   3    Anchor, DisplayPoint, Editor, EditorMode, EditorSnapshot, Input, Scroll, Select, SelectPhase,
   4    SoftWrap, ToPoint, MAX_LINE_LEN,
   5};
   6use crate::{
   7    display_map::{DisplaySnapshot, TransformBlock},
   8    EditorStyle, GoToDefinition,
   9};
  10use clock::ReplicaId;
  11use collections::{BTreeMap, HashMap};
  12use gpui::{
  13    color::Color,
  14    elements::*,
  15    fonts::{HighlightStyle, Underline},
  16    geometry::{
  17        rect::RectF,
  18        vector::{vec2f, Vector2F},
  19        PathBuilder,
  20    },
  21    json::{self, ToJson},
  22    platform::CursorStyle,
  23    text_layout::{self, Line, RunStyle, TextLayoutCache},
  24    AppContext, Axis, Border, CursorRegion, Element, ElementBox, Event, EventContext,
  25    LayoutContext, MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext,
  26    WeakViewHandle,
  27};
  28use json::json;
  29use language::{Bias, DiagnosticSeverity, Selection};
  30use settings::Settings;
  31use smallvec::SmallVec;
  32use std::{
  33    cmp::{self, Ordering},
  34    fmt::Write,
  35    iter,
  36    ops::Range,
  37};
  38
  39struct SelectionLayout {
  40    head: DisplayPoint,
  41    range: Range<DisplayPoint>,
  42}
  43
  44impl SelectionLayout {
  45    fn new<T: ToPoint + ToDisplayPoint + Clone>(
  46        selection: Selection<T>,
  47        line_mode: bool,
  48        map: &DisplaySnapshot,
  49    ) -> Self {
  50        if line_mode {
  51            let selection = selection.map(|p| p.to_point(&map.buffer_snapshot));
  52            let point_range = map.expand_to_line(selection.range());
  53            Self {
  54                head: selection.head().to_display_point(map),
  55                range: point_range.start.to_display_point(map)
  56                    ..point_range.end.to_display_point(map),
  57            }
  58        } else {
  59            let selection = selection.map(|p| p.to_display_point(map));
  60            Self {
  61                head: selection.head(),
  62                range: selection.range(),
  63            }
  64        }
  65    }
  66}
  67
  68pub struct EditorElement {
  69    view: WeakViewHandle<Editor>,
  70    style: EditorStyle,
  71    cursor_shape: CursorShape,
  72}
  73
  74impl EditorElement {
  75    pub fn new(
  76        view: WeakViewHandle<Editor>,
  77        style: EditorStyle,
  78        cursor_shape: CursorShape,
  79    ) -> Self {
  80        Self {
  81            view,
  82            style,
  83            cursor_shape,
  84        }
  85    }
  86
  87    fn view<'a>(&self, cx: &'a AppContext) -> &'a Editor {
  88        self.view.upgrade(cx).unwrap().read(cx)
  89    }
  90
  91    fn update_view<F, T>(&self, cx: &mut MutableAppContext, f: F) -> T
  92    where
  93        F: FnOnce(&mut Editor, &mut ViewContext<Editor>) -> T,
  94    {
  95        self.view.upgrade(cx).unwrap().update(cx, f)
  96    }
  97
  98    fn snapshot(&self, cx: &mut MutableAppContext) -> EditorSnapshot {
  99        self.update_view(cx, |view, cx| view.snapshot(cx))
 100    }
 101
 102    fn mouse_down(
 103        &self,
 104        position: Vector2F,
 105        cmd: bool,
 106        alt: bool,
 107        shift: bool,
 108        mut click_count: usize,
 109        layout: &mut LayoutState,
 110        paint: &mut PaintState,
 111        cx: &mut EventContext,
 112    ) -> bool {
 113        if paint.gutter_bounds.contains_point(position) {
 114            click_count = 3; // Simulate triple-click when clicking the gutter to select lines
 115        } else if !paint.text_bounds.contains_point(position) {
 116            return false;
 117        }
 118
 119        let snapshot = self.snapshot(cx.app);
 120        let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
 121
 122        if cmd {
 123            cx.dispatch_action(GoToDefinitionAt {
 124                location: Some(position),
 125            });
 126        } else if shift && alt {
 127            cx.dispatch_action(Select(SelectPhase::BeginColumnar {
 128                position,
 129                overshoot,
 130            }));
 131        } else if shift {
 132            cx.dispatch_action(Select(SelectPhase::Extend {
 133                position,
 134                click_count,
 135            }));
 136        } else {
 137            cx.dispatch_action(Select(SelectPhase::Begin {
 138                position,
 139                add: alt,
 140                click_count,
 141            }));
 142        }
 143
 144        true
 145    }
 146
 147    fn mouse_up(&self, _position: Vector2F, cx: &mut EventContext) -> bool {
 148        if self.view(cx.app.as_ref()).is_selecting() {
 149            cx.dispatch_action(Select(SelectPhase::End));
 150            true
 151        } else {
 152            false
 153        }
 154    }
 155
 156    fn mouse_dragged(
 157        &self,
 158        position: Vector2F,
 159        layout: &mut LayoutState,
 160        paint: &mut PaintState,
 161        cx: &mut EventContext,
 162    ) -> bool {
 163        let view = self.view(cx.app.as_ref());
 164
 165        if view.is_selecting() {
 166            let rect = paint.text_bounds;
 167            let mut scroll_delta = Vector2F::zero();
 168
 169            let vertical_margin = layout.line_height.min(rect.height() / 3.0);
 170            let top = rect.origin_y() + vertical_margin;
 171            let bottom = rect.lower_left().y() - vertical_margin;
 172            if position.y() < top {
 173                scroll_delta.set_y(-scale_vertical_mouse_autoscroll_delta(top - position.y()))
 174            }
 175            if position.y() > bottom {
 176                scroll_delta.set_y(scale_vertical_mouse_autoscroll_delta(position.y() - bottom))
 177            }
 178
 179            let horizontal_margin = layout.line_height.min(rect.width() / 3.0);
 180            let left = rect.origin_x() + horizontal_margin;
 181            let right = rect.upper_right().x() - horizontal_margin;
 182            if position.x() < left {
 183                scroll_delta.set_x(-scale_horizontal_mouse_autoscroll_delta(
 184                    left - position.x(),
 185                ))
 186            }
 187            if position.x() > right {
 188                scroll_delta.set_x(scale_horizontal_mouse_autoscroll_delta(
 189                    position.x() - right,
 190                ))
 191            }
 192
 193            let snapshot = self.snapshot(cx.app);
 194            let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
 195
 196            cx.dispatch_action(Select(SelectPhase::Update {
 197                position,
 198                overshoot,
 199                scroll_position: (snapshot.scroll_position() + scroll_delta)
 200                    .clamp(Vector2F::zero(), layout.scroll_max),
 201            }));
 202            true
 203        } else {
 204            false
 205        }
 206    }
 207
 208    fn key_down(&self, input: Option<&str>, cx: &mut EventContext) -> bool {
 209        let view = self.view.upgrade(cx.app).unwrap();
 210
 211        if view.is_focused(cx.app) {
 212            if let Some(input) = input {
 213                cx.dispatch_action(Input(input.to_string()));
 214                true
 215            } else {
 216                false
 217            }
 218        } else {
 219            false
 220        }
 221    }
 222
 223    fn scroll(
 224        &self,
 225        position: Vector2F,
 226        mut delta: Vector2F,
 227        precise: bool,
 228        layout: &mut LayoutState,
 229        paint: &mut PaintState,
 230        cx: &mut EventContext,
 231    ) -> bool {
 232        if !paint.bounds.contains_point(position) {
 233            return false;
 234        }
 235
 236        let snapshot = self.snapshot(cx.app);
 237        let max_glyph_width = layout.em_width;
 238        if !precise {
 239            delta *= vec2f(max_glyph_width, layout.line_height);
 240        }
 241
 242        let scroll_position = snapshot.scroll_position();
 243        let x = (scroll_position.x() * max_glyph_width - delta.x()) / max_glyph_width;
 244        let y = (scroll_position.y() * layout.line_height - delta.y()) / layout.line_height;
 245        let scroll_position = vec2f(x, y).clamp(Vector2F::zero(), layout.scroll_max);
 246
 247        cx.dispatch_action(Scroll(scroll_position));
 248
 249        true
 250    }
 251
 252    fn paint_background(
 253        &self,
 254        gutter_bounds: RectF,
 255        text_bounds: RectF,
 256        layout: &LayoutState,
 257        cx: &mut PaintContext,
 258    ) {
 259        let bounds = gutter_bounds.union_rect(text_bounds);
 260        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 261        let editor = self.view(cx.app);
 262        cx.scene.push_quad(Quad {
 263            bounds: gutter_bounds,
 264            background: Some(self.style.gutter_background),
 265            border: Border::new(0., Color::transparent_black()),
 266            corner_radius: 0.,
 267        });
 268        cx.scene.push_quad(Quad {
 269            bounds: text_bounds,
 270            background: Some(self.style.background),
 271            border: Border::new(0., Color::transparent_black()),
 272            corner_radius: 0.,
 273        });
 274
 275        if let EditorMode::Full = editor.mode {
 276            let mut active_rows = layout.active_rows.iter().peekable();
 277            while let Some((start_row, contains_non_empty_selection)) = active_rows.next() {
 278                let mut end_row = *start_row;
 279                while active_rows.peek().map_or(false, |r| {
 280                    *r.0 == end_row + 1 && r.1 == contains_non_empty_selection
 281                }) {
 282                    active_rows.next().unwrap();
 283                    end_row += 1;
 284                }
 285
 286                if !contains_non_empty_selection {
 287                    let origin = vec2f(
 288                        bounds.origin_x(),
 289                        bounds.origin_y() + (layout.line_height * *start_row as f32) - scroll_top,
 290                    );
 291                    let size = vec2f(
 292                        bounds.width(),
 293                        layout.line_height * (end_row - start_row + 1) as f32,
 294                    );
 295                    cx.scene.push_quad(Quad {
 296                        bounds: RectF::new(origin, size),
 297                        background: Some(self.style.active_line_background),
 298                        border: Border::default(),
 299                        corner_radius: 0.,
 300                    });
 301                }
 302            }
 303
 304            if let Some(highlighted_rows) = &layout.highlighted_rows {
 305                let origin = vec2f(
 306                    bounds.origin_x(),
 307                    bounds.origin_y() + (layout.line_height * highlighted_rows.start as f32)
 308                        - scroll_top,
 309                );
 310                let size = vec2f(
 311                    bounds.width(),
 312                    layout.line_height * highlighted_rows.len() as f32,
 313                );
 314                cx.scene.push_quad(Quad {
 315                    bounds: RectF::new(origin, size),
 316                    background: Some(self.style.highlighted_line_background),
 317                    border: Border::default(),
 318                    corner_radius: 0.,
 319                });
 320            }
 321        }
 322    }
 323
 324    fn paint_gutter(
 325        &mut self,
 326        bounds: RectF,
 327        visible_bounds: RectF,
 328        layout: &mut LayoutState,
 329        cx: &mut PaintContext,
 330    ) {
 331        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 332        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
 333            if let Some(line) = line {
 334                let line_origin = bounds.origin()
 335                    + vec2f(
 336                        bounds.width() - line.width() - layout.gutter_padding,
 337                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
 338                    );
 339                line.paint(line_origin, visible_bounds, layout.line_height, cx);
 340            }
 341        }
 342
 343        if let Some((row, indicator)) = layout.code_actions_indicator.as_mut() {
 344            let mut x = bounds.width() - layout.gutter_padding;
 345            let mut y = *row as f32 * layout.line_height - scroll_top;
 346            x += ((layout.gutter_padding + layout.gutter_margin) - indicator.size().x()) / 2.;
 347            y += (layout.line_height - indicator.size().y()) / 2.;
 348            indicator.paint(bounds.origin() + vec2f(x, y), visible_bounds, cx);
 349        }
 350    }
 351
 352    fn paint_text(
 353        &mut self,
 354        bounds: RectF,
 355        visible_bounds: RectF,
 356        layout: &mut LayoutState,
 357        cx: &mut PaintContext,
 358    ) {
 359        let view = self.view(cx.app);
 360        let style = &self.style;
 361        let local_replica_id = view.replica_id(cx);
 362        let scroll_position = layout.snapshot.scroll_position();
 363        let start_row = scroll_position.y() as u32;
 364        let scroll_top = scroll_position.y() * layout.line_height;
 365        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 366        let max_glyph_width = layout.em_width;
 367        let scroll_left = scroll_position.x() * max_glyph_width;
 368        let content_origin = bounds.origin() + vec2f(layout.gutter_margin, 0.);
 369
 370        cx.scene.push_layer(Some(bounds));
 371        cx.scene.push_cursor_region(CursorRegion {
 372            bounds,
 373            style: CursorStyle::IBeam,
 374        });
 375
 376        for (range, color) in &layout.highlighted_ranges {
 377            self.paint_highlighted_range(
 378                range.clone(),
 379                start_row,
 380                end_row,
 381                *color,
 382                0.,
 383                0.15 * layout.line_height,
 384                layout,
 385                content_origin,
 386                scroll_top,
 387                scroll_left,
 388                bounds,
 389                cx,
 390            );
 391        }
 392
 393        let mut cursors = SmallVec::<[Cursor; 32]>::new();
 394        for (replica_id, selections) in &layout.selections {
 395            let selection_style = style.replica_selection_style(*replica_id);
 396            let corner_radius = 0.15 * layout.line_height;
 397
 398            for selection in selections {
 399                self.paint_highlighted_range(
 400                    selection.range.clone(),
 401                    start_row,
 402                    end_row,
 403                    selection_style.selection,
 404                    corner_radius,
 405                    corner_radius * 2.,
 406                    layout,
 407                    content_origin,
 408                    scroll_top,
 409                    scroll_left,
 410                    bounds,
 411                    cx,
 412                );
 413
 414                if view.show_local_cursors() || *replica_id != local_replica_id {
 415                    let cursor_position = selection.head;
 416                    if (start_row..end_row).contains(&cursor_position.row()) {
 417                        let cursor_row_layout =
 418                            &layout.line_layouts[(cursor_position.row() - start_row) as usize];
 419                        let cursor_column = cursor_position.column() as usize;
 420
 421                        let cursor_character_x = cursor_row_layout.x_for_index(cursor_column);
 422                        let mut block_width =
 423                            cursor_row_layout.x_for_index(cursor_column + 1) - cursor_character_x;
 424                        if block_width == 0.0 {
 425                            block_width = layout.em_width;
 426                        }
 427
 428                        let block_text =
 429                            if matches!(self.cursor_shape, CursorShape::Block) {
 430                                layout.snapshot.chars_at(cursor_position).next().and_then(
 431                                    |character| {
 432                                        let font_id =
 433                                            cursor_row_layout.font_for_index(cursor_column)?;
 434                                        let text = character.to_string();
 435
 436                                        Some(cx.text_layout_cache.layout_str(
 437                                            &text,
 438                                            cursor_row_layout.font_size(),
 439                                            &[(
 440                                                text.len(),
 441                                                RunStyle {
 442                                                    font_id,
 443                                                    color: style.background,
 444                                                    underline: Default::default(),
 445                                                },
 446                                            )],
 447                                        ))
 448                                    },
 449                                )
 450                            } else {
 451                                None
 452                            };
 453
 454                        let x = cursor_character_x - scroll_left;
 455                        let y = cursor_position.row() as f32 * layout.line_height - scroll_top;
 456                        cursors.push(Cursor {
 457                            color: selection_style.cursor,
 458                            block_width,
 459                            origin: content_origin + vec2f(x, y),
 460                            line_height: layout.line_height,
 461                            shape: self.cursor_shape,
 462                            block_text,
 463                        });
 464                    }
 465                }
 466            }
 467        }
 468
 469        if let Some(visible_text_bounds) = bounds.intersection(visible_bounds) {
 470            // Draw glyphs
 471            for (ix, line) in layout.line_layouts.iter().enumerate() {
 472                let row = start_row + ix as u32;
 473                line.paint(
 474                    content_origin
 475                        + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
 476                    visible_text_bounds,
 477                    layout.line_height,
 478                    cx,
 479                );
 480            }
 481        }
 482
 483        cx.scene.push_layer(Some(bounds));
 484        for cursor in cursors {
 485            cursor.paint(cx);
 486        }
 487        cx.scene.pop_layer();
 488
 489        if let Some((position, context_menu)) = layout.context_menu.as_mut() {
 490            cx.scene.push_stacking_context(None);
 491
 492            let cursor_row_layout = &layout.line_layouts[(position.row() - start_row) as usize];
 493            let x = cursor_row_layout.x_for_index(position.column() as usize) - scroll_left;
 494            let y = (position.row() + 1) as f32 * layout.line_height - scroll_top;
 495            let mut list_origin = content_origin + vec2f(x, y);
 496            let list_height = context_menu.size().y();
 497
 498            if list_origin.y() + list_height > bounds.lower_left().y() {
 499                list_origin.set_y(list_origin.y() - layout.line_height - list_height);
 500            }
 501
 502            context_menu.paint(
 503                list_origin,
 504                RectF::from_points(Vector2F::zero(), vec2f(f32::MAX, f32::MAX)), // Let content bleed outside of editor
 505                cx,
 506            );
 507
 508            cx.scene.pop_stacking_context();
 509        }
 510
 511        cx.scene.pop_layer();
 512    }
 513
 514    fn paint_highlighted_range(
 515        &self,
 516        range: Range<DisplayPoint>,
 517        start_row: u32,
 518        end_row: u32,
 519        color: Color,
 520        corner_radius: f32,
 521        line_end_overshoot: f32,
 522        layout: &LayoutState,
 523        content_origin: Vector2F,
 524        scroll_top: f32,
 525        scroll_left: f32,
 526        bounds: RectF,
 527        cx: &mut PaintContext,
 528    ) {
 529        if range.start != range.end {
 530            let row_range = if range.end.column() == 0 {
 531                cmp::max(range.start.row(), start_row)..cmp::min(range.end.row(), end_row)
 532            } else {
 533                cmp::max(range.start.row(), start_row)..cmp::min(range.end.row() + 1, end_row)
 534            };
 535
 536            let highlighted_range = HighlightedRange {
 537                color,
 538                line_height: layout.line_height,
 539                corner_radius,
 540                start_y: content_origin.y() + row_range.start as f32 * layout.line_height
 541                    - scroll_top,
 542                lines: row_range
 543                    .into_iter()
 544                    .map(|row| {
 545                        let line_layout = &layout.line_layouts[(row - start_row) as usize];
 546                        HighlightedRangeLine {
 547                            start_x: if row == range.start.row() {
 548                                content_origin.x()
 549                                    + line_layout.x_for_index(range.start.column() as usize)
 550                                    - scroll_left
 551                            } else {
 552                                content_origin.x() - scroll_left
 553                            },
 554                            end_x: if row == range.end.row() {
 555                                content_origin.x()
 556                                    + line_layout.x_for_index(range.end.column() as usize)
 557                                    - scroll_left
 558                            } else {
 559                                content_origin.x() + line_layout.width() + line_end_overshoot
 560                                    - scroll_left
 561                            },
 562                        }
 563                    })
 564                    .collect(),
 565            };
 566
 567            highlighted_range.paint(bounds, cx.scene);
 568        }
 569    }
 570
 571    fn paint_blocks(
 572        &mut self,
 573        bounds: RectF,
 574        visible_bounds: RectF,
 575        layout: &mut LayoutState,
 576        cx: &mut PaintContext,
 577    ) {
 578        let scroll_position = layout.snapshot.scroll_position();
 579        let scroll_left = scroll_position.x() * layout.em_width;
 580        let scroll_top = scroll_position.y() * layout.line_height;
 581
 582        for (row, element) in &mut layout.blocks {
 583            let origin = bounds.origin()
 584                + vec2f(-scroll_left, *row as f32 * layout.line_height - scroll_top);
 585            element.paint(origin, visible_bounds, cx);
 586        }
 587    }
 588
 589    fn max_line_number_width(&self, snapshot: &EditorSnapshot, cx: &LayoutContext) -> f32 {
 590        let digit_count = (snapshot.max_buffer_row() as f32).log10().floor() as usize + 1;
 591        let style = &self.style;
 592
 593        cx.text_layout_cache
 594            .layout_str(
 595                "1".repeat(digit_count).as_str(),
 596                style.text.font_size,
 597                &[(
 598                    digit_count,
 599                    RunStyle {
 600                        font_id: style.text.font_id,
 601                        color: Color::black(),
 602                        underline: Default::default(),
 603                    },
 604                )],
 605            )
 606            .width()
 607    }
 608
 609    fn layout_line_numbers(
 610        &self,
 611        rows: Range<u32>,
 612        active_rows: &BTreeMap<u32, bool>,
 613        snapshot: &EditorSnapshot,
 614        cx: &LayoutContext,
 615    ) -> Vec<Option<text_layout::Line>> {
 616        let style = &self.style;
 617        let include_line_numbers = snapshot.mode == EditorMode::Full;
 618        let mut line_number_layouts = Vec::with_capacity(rows.len());
 619        let mut line_number = String::new();
 620        for (ix, row) in snapshot
 621            .buffer_rows(rows.start)
 622            .take((rows.end - rows.start) as usize)
 623            .enumerate()
 624        {
 625            let display_row = rows.start + ix as u32;
 626            let color = if active_rows.contains_key(&display_row) {
 627                style.line_number_active
 628            } else {
 629                style.line_number
 630            };
 631            if let Some(buffer_row) = row {
 632                if include_line_numbers {
 633                    line_number.clear();
 634                    write!(&mut line_number, "{}", buffer_row + 1).unwrap();
 635                    line_number_layouts.push(Some(cx.text_layout_cache.layout_str(
 636                        &line_number,
 637                        style.text.font_size,
 638                        &[(
 639                            line_number.len(),
 640                            RunStyle {
 641                                font_id: style.text.font_id,
 642                                color,
 643                                underline: Default::default(),
 644                            },
 645                        )],
 646                    )));
 647                }
 648            } else {
 649                line_number_layouts.push(None);
 650            }
 651        }
 652
 653        line_number_layouts
 654    }
 655
 656    fn layout_lines(
 657        &mut self,
 658        rows: Range<u32>,
 659        snapshot: &EditorSnapshot,
 660        cx: &LayoutContext,
 661    ) -> Vec<text_layout::Line> {
 662        if rows.start >= rows.end {
 663            return Vec::new();
 664        }
 665
 666        // When the editor is empty and unfocused, then show the placeholder.
 667        if snapshot.is_empty() && !snapshot.is_focused() {
 668            let placeholder_style = self
 669                .style
 670                .placeholder_text
 671                .as_ref()
 672                .unwrap_or_else(|| &self.style.text);
 673            let placeholder_text = snapshot.placeholder_text();
 674            let placeholder_lines = placeholder_text
 675                .as_ref()
 676                .map_or("", AsRef::as_ref)
 677                .split('\n')
 678                .skip(rows.start as usize)
 679                .chain(iter::repeat(""))
 680                .take(rows.len());
 681            return placeholder_lines
 682                .map(|line| {
 683                    cx.text_layout_cache.layout_str(
 684                        line,
 685                        placeholder_style.font_size,
 686                        &[(
 687                            line.len(),
 688                            RunStyle {
 689                                font_id: placeholder_style.font_id,
 690                                color: placeholder_style.color,
 691                                underline: Default::default(),
 692                            },
 693                        )],
 694                    )
 695                })
 696                .collect();
 697        } else {
 698            let style = &self.style;
 699            let chunks = snapshot.chunks(rows.clone(), true).map(|chunk| {
 700                let mut highlight_style = chunk
 701                    .syntax_highlight_id
 702                    .and_then(|id| id.style(&style.syntax));
 703
 704                if let Some(chunk_highlight) = chunk.highlight_style {
 705                    if let Some(highlight_style) = highlight_style.as_mut() {
 706                        highlight_style.highlight(chunk_highlight);
 707                    } else {
 708                        highlight_style = Some(chunk_highlight);
 709                    }
 710                }
 711
 712                let mut diagnostic_highlight = HighlightStyle::default();
 713
 714                if chunk.is_unnecessary {
 715                    diagnostic_highlight.fade_out = Some(style.unnecessary_code_fade);
 716                }
 717
 718                if let Some(severity) = chunk.diagnostic_severity {
 719                    // Omit underlines for HINT/INFO diagnostics on 'unnecessary' code.
 720                    if severity <= DiagnosticSeverity::WARNING || !chunk.is_unnecessary {
 721                        let diagnostic_style = super::diagnostic_style(severity, true, style);
 722                        diagnostic_highlight.underline = Some(Underline {
 723                            color: Some(diagnostic_style.message.text.color),
 724                            thickness: 1.0.into(),
 725                            squiggly: true,
 726                        });
 727                    }
 728                }
 729
 730                if let Some(highlight_style) = highlight_style.as_mut() {
 731                    highlight_style.highlight(diagnostic_highlight);
 732                } else {
 733                    highlight_style = Some(diagnostic_highlight);
 734                }
 735
 736                (chunk.text, highlight_style)
 737            });
 738            layout_highlighted_chunks(
 739                chunks,
 740                &style.text,
 741                &cx.text_layout_cache,
 742                &cx.font_cache,
 743                MAX_LINE_LEN,
 744                rows.len() as usize,
 745            )
 746        }
 747    }
 748
 749    fn layout_blocks(
 750        &mut self,
 751        rows: Range<u32>,
 752        snapshot: &EditorSnapshot,
 753        width: f32,
 754        gutter_padding: f32,
 755        gutter_width: f32,
 756        em_width: f32,
 757        text_x: f32,
 758        line_height: f32,
 759        style: &EditorStyle,
 760        line_layouts: &[text_layout::Line],
 761        cx: &mut LayoutContext,
 762    ) -> Vec<(u32, ElementBox)> {
 763        let editor = if let Some(editor) = self.view.upgrade(cx) {
 764            editor
 765        } else {
 766            return Default::default();
 767        };
 768
 769        let scroll_x = snapshot.scroll_position.x();
 770        snapshot
 771            .blocks_in_range(rows.clone())
 772            .map(|(block_row, block)| {
 773                let mut element = match block {
 774                    TransformBlock::Custom(block) => {
 775                        let align_to = block
 776                            .position()
 777                            .to_point(&snapshot.buffer_snapshot)
 778                            .to_display_point(snapshot);
 779                        let anchor_x = text_x
 780                            + if rows.contains(&align_to.row()) {
 781                                line_layouts[(align_to.row() - rows.start) as usize]
 782                                    .x_for_index(align_to.column() as usize)
 783                            } else {
 784                                layout_line(align_to.row(), snapshot, style, cx.text_layout_cache)
 785                                    .x_for_index(align_to.column() as usize)
 786                            };
 787
 788                        cx.render(&editor, |_, cx| {
 789                            block.render(&mut BlockContext {
 790                                cx,
 791                                anchor_x,
 792                                gutter_padding,
 793                                line_height,
 794                                scroll_x,
 795                                gutter_width,
 796                                em_width,
 797                            })
 798                        })
 799                    }
 800                    TransformBlock::ExcerptHeader {
 801                        buffer,
 802                        starts_new_buffer,
 803                        ..
 804                    } => {
 805                        if *starts_new_buffer {
 806                            let style = &self.style.diagnostic_path_header;
 807                            let font_size =
 808                                (style.text_scale_factor * self.style.text.font_size).round();
 809
 810                            let mut filename = None;
 811                            let mut parent_path = None;
 812                            if let Some(path) = buffer.path() {
 813                                filename =
 814                                    path.file_name().map(|f| f.to_string_lossy().to_string());
 815                                parent_path =
 816                                    path.parent().map(|p| p.to_string_lossy().to_string() + "/");
 817                            }
 818
 819                            Flex::row()
 820                                .with_child(
 821                                    Label::new(
 822                                        filename.unwrap_or_else(|| "untitled".to_string()),
 823                                        style.filename.text.clone().with_font_size(font_size),
 824                                    )
 825                                    .contained()
 826                                    .with_style(style.filename.container)
 827                                    .boxed(),
 828                                )
 829                                .with_children(parent_path.map(|path| {
 830                                    Label::new(
 831                                        path,
 832                                        style.path.text.clone().with_font_size(font_size),
 833                                    )
 834                                    .contained()
 835                                    .with_style(style.path.container)
 836                                    .boxed()
 837                                }))
 838                                .aligned()
 839                                .left()
 840                                .contained()
 841                                .with_style(style.container)
 842                                .with_padding_left(gutter_padding + scroll_x * em_width)
 843                                .expanded()
 844                                .named("path header block")
 845                        } else {
 846                            let text_style = self.style.text.clone();
 847                            Label::new("".to_string(), text_style)
 848                                .contained()
 849                                .with_padding_left(gutter_padding + scroll_x * em_width)
 850                                .named("collapsed context")
 851                        }
 852                    }
 853                };
 854
 855                element.layout(
 856                    SizeConstraint {
 857                        min: Vector2F::zero(),
 858                        max: vec2f(width, block.height() as f32 * line_height),
 859                    },
 860                    cx,
 861                );
 862                (block_row, element)
 863            })
 864            .collect()
 865    }
 866}
 867
 868impl Element for EditorElement {
 869    type LayoutState = LayoutState;
 870    type PaintState = PaintState;
 871
 872    fn layout(
 873        &mut self,
 874        constraint: SizeConstraint,
 875        cx: &mut LayoutContext,
 876    ) -> (Vector2F, Self::LayoutState) {
 877        let mut size = constraint.max;
 878        if size.x().is_infinite() {
 879            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 880        }
 881
 882        let snapshot = self.snapshot(cx.app);
 883        let style = self.style.clone();
 884        let line_height = style.text.line_height(cx.font_cache);
 885
 886        let gutter_padding;
 887        let gutter_width;
 888        let gutter_margin;
 889        if snapshot.mode == EditorMode::Full {
 890            gutter_padding = style.text.em_width(cx.font_cache) * style.gutter_padding_factor;
 891            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 892            gutter_margin = -style.text.descent(cx.font_cache);
 893        } else {
 894            gutter_padding = 0.0;
 895            gutter_width = 0.0;
 896            gutter_margin = 0.0;
 897        };
 898
 899        let text_width = size.x() - gutter_width;
 900        let em_width = style.text.em_width(cx.font_cache);
 901        let em_advance = style.text.em_advance(cx.font_cache);
 902        let overscroll = vec2f(em_width, 0.);
 903        let snapshot = self.update_view(cx.app, |view, cx| {
 904            let wrap_width = match view.soft_wrap_mode(cx) {
 905                SoftWrap::None => Some((MAX_LINE_LEN / 2) as f32 * em_advance),
 906                SoftWrap::EditorWidth => {
 907                    Some(text_width - gutter_margin - overscroll.x() - em_width)
 908                }
 909                SoftWrap::Column(column) => Some(column as f32 * em_advance),
 910            };
 911
 912            if view.set_wrap_width(wrap_width, cx) {
 913                view.snapshot(cx)
 914            } else {
 915                snapshot
 916            }
 917        });
 918
 919        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
 920        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
 921            size.set_y(
 922                scroll_height
 923                    .min(constraint.max_along(Axis::Vertical))
 924                    .max(constraint.min_along(Axis::Vertical))
 925                    .min(line_height * max_lines as f32),
 926            )
 927        } else if let EditorMode::SingleLine = snapshot.mode {
 928            size.set_y(
 929                line_height
 930                    .min(constraint.max_along(Axis::Vertical))
 931                    .max(constraint.min_along(Axis::Vertical)),
 932            )
 933        } else if size.y().is_infinite() {
 934            size.set_y(scroll_height);
 935        }
 936        let gutter_size = vec2f(gutter_width, size.y());
 937        let text_size = vec2f(text_width, size.y());
 938
 939        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
 940            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
 941            let snapshot = view.snapshot(cx);
 942            (autoscroll_horizontally, snapshot)
 943        });
 944
 945        let scroll_position = snapshot.scroll_position();
 946        let start_row = scroll_position.y() as u32;
 947        let scroll_top = scroll_position.y() * line_height;
 948
 949        // Add 1 to ensure selections bleed off screen
 950        let end_row = 1 + cmp::min(
 951            ((scroll_top + size.y()) / line_height).ceil() as u32,
 952            snapshot.max_point().row(),
 953        );
 954
 955        let start_anchor = if start_row == 0 {
 956            Anchor::min()
 957        } else {
 958            snapshot
 959                .buffer_snapshot
 960                .anchor_before(DisplayPoint::new(start_row, 0).to_offset(&snapshot, Bias::Left))
 961        };
 962        let end_anchor = if end_row > snapshot.max_point().row() {
 963            Anchor::max()
 964        } else {
 965            snapshot
 966                .buffer_snapshot
 967                .anchor_before(DisplayPoint::new(end_row, 0).to_offset(&snapshot, Bias::Right))
 968        };
 969
 970        let mut selections: Vec<(ReplicaId, Vec<SelectionLayout>)> = Vec::new();
 971        let mut active_rows = BTreeMap::new();
 972        let mut highlighted_rows = None;
 973        let mut highlighted_ranges = Vec::new();
 974        self.update_view(cx.app, |view, cx| {
 975            let display_map = view.display_map.update(cx, |map, cx| map.snapshot(cx));
 976
 977            highlighted_rows = view.highlighted_rows();
 978            let theme = cx.global::<Settings>().theme.as_ref();
 979            highlighted_ranges = view.background_highlights_in_range(
 980                start_anchor.clone()..end_anchor.clone(),
 981                &display_map,
 982                theme,
 983            );
 984
 985            let mut remote_selections = HashMap::default();
 986            for (replica_id, line_mode, selection) in display_map
 987                .buffer_snapshot
 988                .remote_selections_in_range(&(start_anchor.clone()..end_anchor.clone()))
 989            {
 990                // The local selections match the leader's selections.
 991                if Some(replica_id) == view.leader_replica_id {
 992                    continue;
 993                }
 994                remote_selections
 995                    .entry(replica_id)
 996                    .or_insert(Vec::new())
 997                    .push(SelectionLayout::new(selection, line_mode, &display_map));
 998            }
 999            selections.extend(remote_selections);
1000
1001            if view.show_local_selections {
1002                let mut local_selections = view
1003                    .selections
1004                    .disjoint_in_range(start_anchor..end_anchor, cx);
1005                local_selections.extend(view.selections.pending(cx));
1006                for selection in &local_selections {
1007                    let is_empty = selection.start == selection.end;
1008                    let selection_start = snapshot.prev_line_boundary(selection.start).1;
1009                    let selection_end = snapshot.next_line_boundary(selection.end).1;
1010                    for row in cmp::max(selection_start.row(), start_row)
1011                        ..=cmp::min(selection_end.row(), end_row)
1012                    {
1013                        let contains_non_empty_selection =
1014                            active_rows.entry(row).or_insert(!is_empty);
1015                        *contains_non_empty_selection |= !is_empty;
1016                    }
1017                }
1018
1019                // Render the local selections in the leader's color when following.
1020                let local_replica_id = view.leader_replica_id.unwrap_or(view.replica_id(cx));
1021
1022                selections.push((
1023                    local_replica_id,
1024                    local_selections
1025                        .into_iter()
1026                        .map(|selection| {
1027                            SelectionLayout::new(selection, view.selections.line_mode, &display_map)
1028                        })
1029                        .collect(),
1030                ));
1031            }
1032        });
1033
1034        let line_number_layouts =
1035            self.layout_line_numbers(start_row..end_row, &active_rows, &snapshot, cx);
1036
1037        let mut max_visible_line_width = 0.0;
1038        let line_layouts = self.layout_lines(start_row..end_row, &snapshot, cx);
1039        for line in &line_layouts {
1040            if line.width() > max_visible_line_width {
1041                max_visible_line_width = line.width();
1042            }
1043        }
1044
1045        let style = self.style.clone();
1046        let longest_line_width = layout_line(
1047            snapshot.longest_row(),
1048            &snapshot,
1049            &style,
1050            cx.text_layout_cache,
1051        )
1052        .width();
1053        let scroll_width = longest_line_width.max(max_visible_line_width) + overscroll.x();
1054        let em_width = style.text.em_width(cx.font_cache);
1055        let max_row = snapshot.max_point().row();
1056        let scroll_max = vec2f(
1057            ((scroll_width - text_size.x()) / em_width).max(0.0),
1058            max_row.saturating_sub(1) as f32,
1059        );
1060
1061        self.update_view(cx.app, |view, cx| {
1062            let clamped = view.clamp_scroll_left(scroll_max.x());
1063            let autoscrolled;
1064            if autoscroll_horizontally {
1065                autoscrolled = view.autoscroll_horizontally(
1066                    start_row,
1067                    text_size.x(),
1068                    scroll_width,
1069                    em_width,
1070                    &line_layouts,
1071                    cx,
1072                );
1073            } else {
1074                autoscrolled = false;
1075            }
1076
1077            if clamped || autoscrolled {
1078                snapshot = view.snapshot(cx);
1079            }
1080        });
1081
1082        let mut context_menu = None;
1083        let mut code_actions_indicator = None;
1084        cx.render(&self.view.upgrade(cx).unwrap(), |view, cx| {
1085            let newest_selection_head = view
1086                .selections
1087                .newest::<usize>(cx)
1088                .head()
1089                .to_display_point(&snapshot);
1090
1091            if (start_row..end_row).contains(&newest_selection_head.row()) {
1092                let style = view.style(cx);
1093                if view.context_menu_visible() {
1094                    context_menu = view.render_context_menu(newest_selection_head, style.clone());
1095                }
1096
1097                code_actions_indicator = view
1098                    .render_code_actions_indicator(&style, cx)
1099                    .map(|indicator| (newest_selection_head.row(), indicator));
1100            }
1101        });
1102
1103        if let Some((_, context_menu)) = context_menu.as_mut() {
1104            context_menu.layout(
1105                SizeConstraint {
1106                    min: Vector2F::zero(),
1107                    max: vec2f(
1108                        f32::INFINITY,
1109                        (12. * line_height).min((size.y() - line_height) / 2.),
1110                    ),
1111                },
1112                cx,
1113            );
1114        }
1115
1116        if let Some((_, indicator)) = code_actions_indicator.as_mut() {
1117            indicator.layout(
1118                SizeConstraint::strict_along(Axis::Vertical, line_height * 0.618),
1119                cx,
1120            );
1121        }
1122
1123        let blocks = self.layout_blocks(
1124            start_row..end_row,
1125            &snapshot,
1126            size.x().max(scroll_width + gutter_width),
1127            gutter_padding,
1128            gutter_width,
1129            em_width,
1130            gutter_width + gutter_margin,
1131            line_height,
1132            &style,
1133            &line_layouts,
1134            cx,
1135        );
1136
1137        (
1138            size,
1139            LayoutState {
1140                size,
1141                scroll_max,
1142                gutter_size,
1143                gutter_padding,
1144                text_size,
1145                gutter_margin,
1146                snapshot,
1147                active_rows,
1148                highlighted_rows,
1149                highlighted_ranges,
1150                line_layouts,
1151                line_number_layouts,
1152                blocks,
1153                line_height,
1154                em_width,
1155                em_advance,
1156                selections,
1157                context_menu,
1158                code_actions_indicator,
1159            },
1160        )
1161    }
1162
1163    fn paint(
1164        &mut self,
1165        bounds: RectF,
1166        visible_bounds: RectF,
1167        layout: &mut Self::LayoutState,
1168        cx: &mut PaintContext,
1169    ) -> Self::PaintState {
1170        cx.scene.push_layer(Some(bounds));
1171
1172        let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
1173        let text_bounds = RectF::new(
1174            bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
1175            layout.text_size,
1176        );
1177
1178        self.paint_background(gutter_bounds, text_bounds, layout, cx);
1179        if layout.gutter_size.x() > 0. {
1180            self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
1181        }
1182        self.paint_text(text_bounds, visible_bounds, layout, cx);
1183
1184        if !layout.blocks.is_empty() {
1185            cx.scene.push_layer(Some(bounds));
1186            self.paint_blocks(bounds, visible_bounds, layout, cx);
1187            cx.scene.pop_layer();
1188        }
1189
1190        cx.scene.pop_layer();
1191
1192        PaintState {
1193            bounds,
1194            gutter_bounds,
1195            text_bounds,
1196        }
1197    }
1198
1199    fn dispatch_event(
1200        &mut self,
1201        event: &Event,
1202        _: RectF,
1203        _: RectF,
1204        layout: &mut LayoutState,
1205        paint: &mut PaintState,
1206        cx: &mut EventContext,
1207    ) -> bool {
1208        if let Some((_, context_menu)) = &mut layout.context_menu {
1209            if context_menu.dispatch_event(event, cx) {
1210                return true;
1211            }
1212        }
1213
1214        if let Some((_, indicator)) = &mut layout.code_actions_indicator {
1215            if indicator.dispatch_event(event, cx) {
1216                return true;
1217            }
1218        }
1219
1220        for (_, block) in &mut layout.blocks {
1221            if block.dispatch_event(event, cx) {
1222                return true;
1223            }
1224        }
1225
1226        match event {
1227            Event::LeftMouseDown {
1228                position,
1229                cmd,
1230                alt,
1231                shift,
1232                click_count,
1233                ..
1234            } => self.mouse_down(
1235                *position,
1236                *cmd,
1237                *alt,
1238                *shift,
1239                *click_count,
1240                layout,
1241                paint,
1242                cx,
1243            ),
1244            Event::LeftMouseUp { position, .. } => self.mouse_up(*position, cx),
1245            Event::LeftMouseDragged { position } => {
1246                self.mouse_dragged(*position, layout, paint, cx)
1247            }
1248            Event::ScrollWheel {
1249                position,
1250                delta,
1251                precise,
1252            } => self.scroll(*position, *delta, *precise, layout, paint, cx),
1253            Event::KeyDown { input, .. } => self.key_down(input.as_deref(), cx),
1254            _ => false,
1255        }
1256    }
1257
1258    fn debug(
1259        &self,
1260        bounds: RectF,
1261        _: &Self::LayoutState,
1262        _: &Self::PaintState,
1263        _: &gpui::DebugContext,
1264    ) -> json::Value {
1265        json!({
1266            "type": "BufferElement",
1267            "bounds": bounds.to_json()
1268        })
1269    }
1270}
1271
1272pub struct LayoutState {
1273    size: Vector2F,
1274    scroll_max: Vector2F,
1275    gutter_size: Vector2F,
1276    gutter_padding: f32,
1277    gutter_margin: f32,
1278    text_size: Vector2F,
1279    snapshot: EditorSnapshot,
1280    active_rows: BTreeMap<u32, bool>,
1281    highlighted_rows: Option<Range<u32>>,
1282    line_layouts: Vec<text_layout::Line>,
1283    line_number_layouts: Vec<Option<text_layout::Line>>,
1284    blocks: Vec<(u32, ElementBox)>,
1285    line_height: f32,
1286    em_width: f32,
1287    em_advance: f32,
1288    highlighted_ranges: Vec<(Range<DisplayPoint>, Color)>,
1289    selections: Vec<(ReplicaId, Vec<SelectionLayout>)>,
1290    context_menu: Option<(DisplayPoint, ElementBox)>,
1291    code_actions_indicator: Option<(u32, ElementBox)>,
1292}
1293
1294fn layout_line(
1295    row: u32,
1296    snapshot: &EditorSnapshot,
1297    style: &EditorStyle,
1298    layout_cache: &TextLayoutCache,
1299) -> text_layout::Line {
1300    let mut line = snapshot.line(row);
1301
1302    if line.len() > MAX_LINE_LEN {
1303        let mut len = MAX_LINE_LEN;
1304        while !line.is_char_boundary(len) {
1305            len -= 1;
1306        }
1307
1308        line.truncate(len);
1309    }
1310
1311    layout_cache.layout_str(
1312        &line,
1313        style.text.font_size,
1314        &[(
1315            snapshot.line_len(row) as usize,
1316            RunStyle {
1317                font_id: style.text.font_id,
1318                color: Color::black(),
1319                underline: Default::default(),
1320            },
1321        )],
1322    )
1323}
1324
1325pub struct PaintState {
1326    bounds: RectF,
1327    gutter_bounds: RectF,
1328    text_bounds: RectF,
1329}
1330
1331impl PaintState {
1332    fn point_for_position(
1333        &self,
1334        snapshot: &EditorSnapshot,
1335        layout: &LayoutState,
1336        position: Vector2F,
1337    ) -> (DisplayPoint, u32) {
1338        let scroll_position = snapshot.scroll_position();
1339        let position = position - self.text_bounds.origin();
1340        let y = position.y().max(0.0).min(layout.size.y());
1341        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
1342        let row = cmp::min(row, snapshot.max_point().row());
1343        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
1344        let x = position.x() + (scroll_position.x() * layout.em_width);
1345
1346        let column = if x >= 0.0 {
1347            line.index_for_x(x)
1348                .map(|ix| ix as u32)
1349                .unwrap_or_else(|| snapshot.line_len(row))
1350        } else {
1351            0
1352        };
1353        let overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
1354
1355        (DisplayPoint::new(row, column), overshoot)
1356    }
1357}
1358
1359#[derive(Copy, Clone, PartialEq, Eq)]
1360pub enum CursorShape {
1361    Bar,
1362    Block,
1363    Underscore,
1364}
1365
1366impl Default for CursorShape {
1367    fn default() -> Self {
1368        CursorShape::Bar
1369    }
1370}
1371
1372struct Cursor {
1373    origin: Vector2F,
1374    block_width: f32,
1375    line_height: f32,
1376    color: Color,
1377    shape: CursorShape,
1378    block_text: Option<Line>,
1379}
1380
1381impl Cursor {
1382    fn paint(&self, cx: &mut PaintContext) {
1383        let bounds = match self.shape {
1384            CursorShape::Bar => RectF::new(self.origin, vec2f(2.0, self.line_height)),
1385            CursorShape::Block => {
1386                RectF::new(self.origin, vec2f(self.block_width, self.line_height))
1387            }
1388            CursorShape::Underscore => RectF::new(
1389                self.origin + Vector2F::new(0.0, self.line_height - 2.0),
1390                vec2f(self.block_width, 2.0),
1391            ),
1392        };
1393
1394        cx.scene.push_quad(Quad {
1395            bounds,
1396            background: Some(self.color),
1397            border: Border::new(0., Color::black()),
1398            corner_radius: 0.,
1399        });
1400
1401        if let Some(block_text) = &self.block_text {
1402            block_text.paint(self.origin, bounds, self.line_height, cx);
1403        }
1404    }
1405}
1406
1407#[derive(Debug)]
1408struct HighlightedRange {
1409    start_y: f32,
1410    line_height: f32,
1411    lines: Vec<HighlightedRangeLine>,
1412    color: Color,
1413    corner_radius: f32,
1414}
1415
1416#[derive(Debug)]
1417struct HighlightedRangeLine {
1418    start_x: f32,
1419    end_x: f32,
1420}
1421
1422impl HighlightedRange {
1423    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1424        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1425            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1426            self.paint_lines(
1427                self.start_y + self.line_height,
1428                &self.lines[1..],
1429                bounds,
1430                scene,
1431            );
1432        } else {
1433            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1434        }
1435    }
1436
1437    fn paint_lines(
1438        &self,
1439        start_y: f32,
1440        lines: &[HighlightedRangeLine],
1441        bounds: RectF,
1442        scene: &mut Scene,
1443    ) {
1444        if lines.is_empty() {
1445            return;
1446        }
1447
1448        let mut path = PathBuilder::new();
1449        let first_line = lines.first().unwrap();
1450        let last_line = lines.last().unwrap();
1451
1452        let first_top_left = vec2f(first_line.start_x, start_y);
1453        let first_top_right = vec2f(first_line.end_x, start_y);
1454
1455        let curve_height = vec2f(0., self.corner_radius);
1456        let curve_width = |start_x: f32, end_x: f32| {
1457            let max = (end_x - start_x) / 2.;
1458            let width = if max < self.corner_radius {
1459                max
1460            } else {
1461                self.corner_radius
1462            };
1463
1464            vec2f(width, 0.)
1465        };
1466
1467        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1468        path.reset(first_top_right - top_curve_width);
1469        path.curve_to(first_top_right + curve_height, first_top_right);
1470
1471        let mut iter = lines.iter().enumerate().peekable();
1472        while let Some((ix, line)) = iter.next() {
1473            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1474
1475            if let Some((_, next_line)) = iter.peek() {
1476                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1477
1478                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1479                    Ordering::Equal => {
1480                        path.line_to(bottom_right);
1481                    }
1482                    Ordering::Less => {
1483                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1484                        path.line_to(bottom_right - curve_height);
1485                        if self.corner_radius > 0. {
1486                            path.curve_to(bottom_right - curve_width, bottom_right);
1487                        }
1488                        path.line_to(next_top_right + curve_width);
1489                        if self.corner_radius > 0. {
1490                            path.curve_to(next_top_right + curve_height, next_top_right);
1491                        }
1492                    }
1493                    Ordering::Greater => {
1494                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1495                        path.line_to(bottom_right - curve_height);
1496                        if self.corner_radius > 0. {
1497                            path.curve_to(bottom_right + curve_width, bottom_right);
1498                        }
1499                        path.line_to(next_top_right - curve_width);
1500                        if self.corner_radius > 0. {
1501                            path.curve_to(next_top_right + curve_height, next_top_right);
1502                        }
1503                    }
1504                }
1505            } else {
1506                let curve_width = curve_width(line.start_x, line.end_x);
1507                path.line_to(bottom_right - curve_height);
1508                if self.corner_radius > 0. {
1509                    path.curve_to(bottom_right - curve_width, bottom_right);
1510                }
1511
1512                let bottom_left = vec2f(line.start_x, bottom_right.y());
1513                path.line_to(bottom_left + curve_width);
1514                if self.corner_radius > 0. {
1515                    path.curve_to(bottom_left - curve_height, bottom_left);
1516                }
1517            }
1518        }
1519
1520        if first_line.start_x > last_line.start_x {
1521            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1522            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1523            path.line_to(second_top_left + curve_height);
1524            if self.corner_radius > 0. {
1525                path.curve_to(second_top_left + curve_width, second_top_left);
1526            }
1527            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1528            path.line_to(first_bottom_left - curve_width);
1529            if self.corner_radius > 0. {
1530                path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1531            }
1532        }
1533
1534        path.line_to(first_top_left + curve_height);
1535        if self.corner_radius > 0. {
1536            path.curve_to(first_top_left + top_curve_width, first_top_left);
1537        }
1538        path.line_to(first_top_right - top_curve_width);
1539
1540        scene.push_path(path.build(self.color, Some(bounds)));
1541    }
1542}
1543
1544fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1545    delta.powf(1.5) / 100.0
1546}
1547
1548fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1549    delta.powf(1.2) / 300.0
1550}
1551
1552#[cfg(test)]
1553mod tests {
1554    use std::sync::Arc;
1555
1556    use super::*;
1557    use crate::{
1558        display_map::{BlockDisposition, BlockProperties},
1559        Editor, MultiBuffer,
1560    };
1561    use settings::Settings;
1562    use util::test::sample_text;
1563
1564    #[gpui::test]
1565    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1566        cx.set_global(Settings::test(cx));
1567        let buffer = MultiBuffer::build_simple(&sample_text(6, 6, 'a'), cx);
1568        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1569            Editor::new(EditorMode::Full, buffer, None, None, None, cx)
1570        });
1571        let element = EditorElement::new(
1572            editor.downgrade(),
1573            editor.read(cx).style(cx),
1574            CursorShape::Bar,
1575        );
1576
1577        let layouts = editor.update(cx, |editor, cx| {
1578            let snapshot = editor.snapshot(cx);
1579            let mut presenter = cx.build_presenter(window_id, 30.);
1580            let mut layout_cx = presenter.build_layout_context(Vector2F::zero(), false, cx);
1581            element.layout_line_numbers(0..6, &Default::default(), &snapshot, &mut layout_cx)
1582        });
1583        assert_eq!(layouts.len(), 6);
1584    }
1585
1586    #[gpui::test]
1587    fn test_layout_with_placeholder_text_and_blocks(cx: &mut gpui::MutableAppContext) {
1588        cx.set_global(Settings::test(cx));
1589        let buffer = MultiBuffer::build_simple("", cx);
1590        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1591            Editor::new(EditorMode::Full, buffer, None, None, None, cx)
1592        });
1593
1594        editor.update(cx, |editor, cx| {
1595            editor.set_placeholder_text("hello", cx);
1596            editor.insert_blocks(
1597                [BlockProperties {
1598                    disposition: BlockDisposition::Above,
1599                    height: 3,
1600                    position: Anchor::min(),
1601                    render: Arc::new(|_| Empty::new().boxed()),
1602                }],
1603                cx,
1604            );
1605
1606            // Blur the editor so that it displays placeholder text.
1607            cx.blur();
1608        });
1609
1610        let mut element = EditorElement::new(
1611            editor.downgrade(),
1612            editor.read(cx).style(cx),
1613            CursorShape::Bar,
1614        );
1615
1616        let mut scene = Scene::new(1.0);
1617        let mut presenter = cx.build_presenter(window_id, 30.);
1618        let mut layout_cx = presenter.build_layout_context(Vector2F::zero(), false, cx);
1619        let (size, mut state) = element.layout(
1620            SizeConstraint::new(vec2f(500., 500.), vec2f(500., 500.)),
1621            &mut layout_cx,
1622        );
1623
1624        assert_eq!(state.line_layouts.len(), 4);
1625        assert_eq!(
1626            state
1627                .line_number_layouts
1628                .iter()
1629                .map(Option::is_some)
1630                .collect::<Vec<_>>(),
1631            &[false, false, false, true]
1632        );
1633
1634        // Don't panic.
1635        let bounds = RectF::new(Default::default(), size);
1636        let mut paint_cx = presenter.build_paint_context(&mut scene, bounds.size(), cx);
1637        element.paint(bounds, bounds, &mut state, &mut paint_cx);
1638    }
1639}