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::hover_popover::HoverAt;
   7use crate::{
   8    display_map::{DisplaySnapshot, TransformBlock},
   9    EditorStyle,
  10};
  11use clock::ReplicaId;
  12use collections::{BTreeMap, HashMap};
  13use gpui::{
  14    color::Color,
  15    elements::*,
  16    fonts::{HighlightStyle, Underline},
  17    geometry::{
  18        rect::RectF,
  19        vector::{vec2f, Vector2F},
  20        PathBuilder,
  21    },
  22    json::{self, ToJson},
  23    platform::CursorStyle,
  24    text_layout::{self, Line, RunStyle, TextLayoutCache},
  25    AppContext, Axis, Border, CursorRegion, Element, ElementBox, Event, EventContext,
  26    LayoutContext, MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext,
  27    WeakViewHandle,
  28};
  29use json::json;
  30use language::{Bias, DiagnosticSeverity, Selection};
  31use project::ProjectPath;
  32use settings::Settings;
  33use smallvec::SmallVec;
  34use std::{
  35    cmp::{self, Ordering},
  36    fmt::Write,
  37    iter,
  38    ops::Range,
  39};
  40
  41struct SelectionLayout {
  42    head: DisplayPoint,
  43    range: Range<DisplayPoint>,
  44}
  45
  46impl SelectionLayout {
  47    fn new<T: ToPoint + ToDisplayPoint + Clone>(
  48        selection: Selection<T>,
  49        line_mode: bool,
  50        map: &DisplaySnapshot,
  51    ) -> Self {
  52        if line_mode {
  53            let selection = selection.map(|p| p.to_point(&map.buffer_snapshot));
  54            let point_range = map.expand_to_line(selection.range());
  55            Self {
  56                head: selection.head().to_display_point(map),
  57                range: point_range.start.to_display_point(map)
  58                    ..point_range.end.to_display_point(map),
  59            }
  60        } else {
  61            let selection = selection.map(|p| p.to_display_point(map));
  62            Self {
  63                head: selection.head(),
  64                range: selection.range(),
  65            }
  66        }
  67    }
  68}
  69
  70pub struct EditorElement {
  71    view: WeakViewHandle<Editor>,
  72    style: EditorStyle,
  73    cursor_shape: CursorShape,
  74}
  75
  76impl EditorElement {
  77    pub fn new(
  78        view: WeakViewHandle<Editor>,
  79        style: EditorStyle,
  80        cursor_shape: CursorShape,
  81    ) -> Self {
  82        Self {
  83            view,
  84            style,
  85            cursor_shape,
  86        }
  87    }
  88
  89    fn view<'a>(&self, cx: &'a AppContext) -> &'a Editor {
  90        self.view.upgrade(cx).unwrap().read(cx)
  91    }
  92
  93    fn update_view<F, T>(&self, cx: &mut MutableAppContext, f: F) -> T
  94    where
  95        F: FnOnce(&mut Editor, &mut ViewContext<Editor>) -> T,
  96    {
  97        self.view.upgrade(cx).unwrap().update(cx, f)
  98    }
  99
 100    fn snapshot(&self, cx: &mut MutableAppContext) -> EditorSnapshot {
 101        self.update_view(cx, |view, cx| view.snapshot(cx))
 102    }
 103
 104    fn mouse_down(
 105        &self,
 106        position: Vector2F,
 107        _: bool,
 108        alt: bool,
 109        shift: bool,
 110        mut click_count: usize,
 111        layout: &mut LayoutState,
 112        paint: &mut PaintState,
 113        cx: &mut EventContext,
 114    ) -> bool {
 115        if paint.gutter_bounds.contains_point(position) {
 116            click_count = 3; // Simulate triple-click when clicking the gutter to select lines
 117        } else if !paint.text_bounds.contains_point(position) {
 118            return false;
 119        }
 120
 121        let snapshot = self.snapshot(cx.app);
 122        let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
 123
 124        if shift && alt {
 125            cx.dispatch_action(Select(SelectPhase::BeginColumnar {
 126                position,
 127                overshoot: overshoot.column(),
 128            }));
 129        } else if shift {
 130            cx.dispatch_action(Select(SelectPhase::Extend {
 131                position,
 132                click_count,
 133            }));
 134        } else {
 135            cx.dispatch_action(Select(SelectPhase::Begin {
 136                position,
 137                add: alt,
 138                click_count,
 139            }));
 140        }
 141
 142        true
 143    }
 144
 145    fn mouse_up(&self, _position: Vector2F, cx: &mut EventContext) -> bool {
 146        if self.view(cx.app.as_ref()).is_selecting() {
 147            cx.dispatch_action(Select(SelectPhase::End));
 148            true
 149        } else {
 150            false
 151        }
 152    }
 153
 154    fn mouse_dragged(
 155        &self,
 156        position: Vector2F,
 157        layout: &mut LayoutState,
 158        paint: &mut PaintState,
 159        cx: &mut EventContext,
 160    ) -> bool {
 161        let view = self.view(cx.app.as_ref());
 162
 163        if view.is_selecting() {
 164            let rect = paint.text_bounds;
 165            let mut scroll_delta = Vector2F::zero();
 166
 167            let vertical_margin = layout.line_height.min(rect.height() / 3.0);
 168            let top = rect.origin_y() + vertical_margin;
 169            let bottom = rect.lower_left().y() - vertical_margin;
 170            if position.y() < top {
 171                scroll_delta.set_y(-scale_vertical_mouse_autoscroll_delta(top - position.y()))
 172            }
 173            if position.y() > bottom {
 174                scroll_delta.set_y(scale_vertical_mouse_autoscroll_delta(position.y() - bottom))
 175            }
 176
 177            let horizontal_margin = layout.line_height.min(rect.width() / 3.0);
 178            let left = rect.origin_x() + horizontal_margin;
 179            let right = rect.upper_right().x() - horizontal_margin;
 180            if position.x() < left {
 181                scroll_delta.set_x(-scale_horizontal_mouse_autoscroll_delta(
 182                    left - position.x(),
 183                ))
 184            }
 185            if position.x() > right {
 186                scroll_delta.set_x(scale_horizontal_mouse_autoscroll_delta(
 187                    position.x() - right,
 188                ))
 189            }
 190
 191            let snapshot = self.snapshot(cx.app);
 192            let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
 193
 194            cx.dispatch_action(Select(SelectPhase::Update {
 195                position,
 196                overshoot: overshoot.column(),
 197                scroll_position: (snapshot.scroll_position() + scroll_delta)
 198                    .clamp(Vector2F::zero(), layout.scroll_max),
 199            }));
 200            true
 201        } else {
 202            false
 203        }
 204    }
 205
 206    fn key_down(&self, input: Option<&str>, cx: &mut EventContext) -> bool {
 207        let view = self.view.upgrade(cx.app).unwrap();
 208
 209        if view.is_focused(cx.app) {
 210            if let Some(input) = input {
 211                cx.dispatch_action(Input(input.to_string()));
 212                true
 213            } else {
 214                false
 215            }
 216        } else {
 217            false
 218        }
 219    }
 220
 221    fn scroll(
 222        &self,
 223        position: Vector2F,
 224        mut delta: Vector2F,
 225        precise: bool,
 226        layout: &mut LayoutState,
 227        paint: &mut PaintState,
 228        cx: &mut EventContext,
 229    ) -> bool {
 230        if !paint.bounds.contains_point(position) {
 231            return false;
 232        }
 233
 234        let snapshot = self.snapshot(cx.app);
 235        let max_glyph_width = layout.em_width;
 236        if !precise {
 237            delta *= vec2f(max_glyph_width, layout.line_height);
 238        }
 239
 240        let scroll_position = snapshot.scroll_position();
 241        let x = (scroll_position.x() * max_glyph_width - delta.x()) / max_glyph_width;
 242        let y = (scroll_position.y() * layout.line_height - delta.y()) / layout.line_height;
 243        let scroll_position = vec2f(x, y).clamp(Vector2F::zero(), layout.scroll_max);
 244
 245        cx.dispatch_action(Scroll(scroll_position));
 246
 247        true
 248    }
 249
 250    fn paint_background(
 251        &self,
 252        gutter_bounds: RectF,
 253        text_bounds: RectF,
 254        layout: &LayoutState,
 255        cx: &mut PaintContext,
 256    ) {
 257        let bounds = gutter_bounds.union_rect(text_bounds);
 258        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 259        let editor = self.view(cx.app);
 260        cx.scene.push_quad(Quad {
 261            bounds: gutter_bounds,
 262            background: Some(self.style.gutter_background),
 263            border: Border::new(0., Color::transparent_black()),
 264            corner_radius: 0.,
 265        });
 266        cx.scene.push_quad(Quad {
 267            bounds: text_bounds,
 268            background: Some(self.style.background),
 269            border: Border::new(0., Color::transparent_black()),
 270            corner_radius: 0.,
 271        });
 272
 273        if let EditorMode::Full = editor.mode {
 274            let mut active_rows = layout.active_rows.iter().peekable();
 275            while let Some((start_row, contains_non_empty_selection)) = active_rows.next() {
 276                let mut end_row = *start_row;
 277                while active_rows.peek().map_or(false, |r| {
 278                    *r.0 == end_row + 1 && r.1 == contains_non_empty_selection
 279                }) {
 280                    active_rows.next().unwrap();
 281                    end_row += 1;
 282                }
 283
 284                if !contains_non_empty_selection {
 285                    let origin = vec2f(
 286                        bounds.origin_x(),
 287                        bounds.origin_y() + (layout.line_height * *start_row as f32) - scroll_top,
 288                    );
 289                    let size = vec2f(
 290                        bounds.width(),
 291                        layout.line_height * (end_row - start_row + 1) as f32,
 292                    );
 293                    cx.scene.push_quad(Quad {
 294                        bounds: RectF::new(origin, size),
 295                        background: Some(self.style.active_line_background),
 296                        border: Border::default(),
 297                        corner_radius: 0.,
 298                    });
 299                }
 300            }
 301
 302            if let Some(highlighted_rows) = &layout.highlighted_rows {
 303                let origin = vec2f(
 304                    bounds.origin_x(),
 305                    bounds.origin_y() + (layout.line_height * highlighted_rows.start as f32)
 306                        - scroll_top,
 307                );
 308                let size = vec2f(
 309                    bounds.width(),
 310                    layout.line_height * highlighted_rows.len() as f32,
 311                );
 312                cx.scene.push_quad(Quad {
 313                    bounds: RectF::new(origin, size),
 314                    background: Some(self.style.highlighted_line_background),
 315                    border: Border::default(),
 316                    corner_radius: 0.,
 317                });
 318            }
 319        }
 320    }
 321
 322    fn paint_gutter(
 323        &mut self,
 324        bounds: RectF,
 325        visible_bounds: RectF,
 326        layout: &mut LayoutState,
 327        cx: &mut PaintContext,
 328    ) {
 329        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 330        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
 331            if let Some(line) = line {
 332                let line_origin = bounds.origin()
 333                    + vec2f(
 334                        bounds.width() - line.width() - layout.gutter_padding,
 335                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
 336                    );
 337                line.paint(line_origin, visible_bounds, layout.line_height, cx);
 338            }
 339        }
 340
 341        if let Some((row, indicator)) = layout.code_actions_indicator.as_mut() {
 342            let mut x = bounds.width() - layout.gutter_padding;
 343            let mut y = *row as f32 * layout.line_height - scroll_top;
 344            x += ((layout.gutter_padding + layout.gutter_margin) - indicator.size().x()) / 2.;
 345            y += (layout.line_height - indicator.size().y()) / 2.;
 346            indicator.paint(bounds.origin() + vec2f(x, y), visible_bounds, cx);
 347        }
 348    }
 349
 350    fn paint_text(
 351        &mut self,
 352        bounds: RectF,
 353        visible_bounds: RectF,
 354        layout: &mut LayoutState,
 355        paint: &mut PaintState,
 356        cx: &mut PaintContext,
 357    ) {
 358        let view = self.view(cx.app);
 359        let style = &self.style;
 360        let local_replica_id = view.replica_id(cx);
 361        let scroll_position = layout.snapshot.scroll_position();
 362        let start_row = scroll_position.y() as u32;
 363        let scroll_top = scroll_position.y() * layout.line_height;
 364        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 365        let max_glyph_width = layout.em_width;
 366        let scroll_left = scroll_position.x() * max_glyph_width;
 367        let content_origin = bounds.origin() + vec2f(layout.gutter_margin, 0.);
 368
 369        cx.scene.push_layer(Some(bounds));
 370        cx.scene.push_cursor_region(CursorRegion {
 371            bounds,
 372            style: CursorStyle::IBeam,
 373        });
 374
 375        for (range, color) in &layout.highlighted_ranges {
 376            self.paint_highlighted_range(
 377                range.clone(),
 378                start_row,
 379                end_row,
 380                *color,
 381                0.,
 382                0.15 * layout.line_height,
 383                layout,
 384                content_origin,
 385                scroll_top,
 386                scroll_left,
 387                bounds,
 388                cx,
 389            );
 390        }
 391
 392        let mut cursors = SmallVec::<[Cursor; 32]>::new();
 393        for (replica_id, selections) in &layout.selections {
 394            let selection_style = style.replica_selection_style(*replica_id);
 395            let corner_radius = 0.15 * layout.line_height;
 396
 397            for selection in selections {
 398                self.paint_highlighted_range(
 399                    selection.range.clone(),
 400                    start_row,
 401                    end_row,
 402                    selection_style.selection,
 403                    corner_radius,
 404                    corner_radius * 2.,
 405                    layout,
 406                    content_origin,
 407                    scroll_top,
 408                    scroll_left,
 409                    bounds,
 410                    cx,
 411                );
 412
 413                if view.show_local_cursors() || *replica_id != local_replica_id {
 414                    let cursor_position = selection.head;
 415                    if (start_row..end_row).contains(&cursor_position.row()) {
 416                        let cursor_row_layout =
 417                            &layout.line_layouts[(cursor_position.row() - start_row) as usize];
 418                        let cursor_column = cursor_position.column() as usize;
 419
 420                        let cursor_character_x = cursor_row_layout.x_for_index(cursor_column);
 421                        let mut block_width =
 422                            cursor_row_layout.x_for_index(cursor_column + 1) - cursor_character_x;
 423                        if block_width == 0.0 {
 424                            block_width = layout.em_width;
 425                        }
 426
 427                        let block_text =
 428                            if matches!(self.cursor_shape, CursorShape::Block) {
 429                                layout.snapshot.chars_at(cursor_position).next().and_then(
 430                                    |character| {
 431                                        let font_id =
 432                                            cursor_row_layout.font_for_index(cursor_column)?;
 433                                        let text = character.to_string();
 434
 435                                        Some(cx.text_layout_cache.layout_str(
 436                                            &text,
 437                                            cursor_row_layout.font_size(),
 438                                            &[(
 439                                                text.len(),
 440                                                RunStyle {
 441                                                    font_id,
 442                                                    color: style.background,
 443                                                    underline: Default::default(),
 444                                                },
 445                                            )],
 446                                        ))
 447                                    },
 448                                )
 449                            } else {
 450                                None
 451                            };
 452
 453                        let x = cursor_character_x - scroll_left;
 454                        let y = cursor_position.row() as f32 * layout.line_height - scroll_top;
 455                        cursors.push(Cursor {
 456                            color: selection_style.cursor,
 457                            block_width,
 458                            origin: content_origin + vec2f(x, y),
 459                            line_height: layout.line_height,
 460                            shape: self.cursor_shape,
 461                            block_text,
 462                        });
 463                    }
 464                }
 465            }
 466        }
 467
 468        if let Some(visible_text_bounds) = bounds.intersection(visible_bounds) {
 469            // Draw glyphs
 470            for (ix, line) in layout.line_layouts.iter().enumerate() {
 471                let row = start_row + ix as u32;
 472                line.paint(
 473                    content_origin
 474                        + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
 475                    visible_text_bounds,
 476                    layout.line_height,
 477                    cx,
 478                );
 479            }
 480        }
 481
 482        cx.scene.push_layer(Some(bounds));
 483        for cursor in cursors {
 484            cursor.paint(cx);
 485        }
 486        cx.scene.pop_layer();
 487
 488        if let Some((position, context_menu)) = layout.context_menu.as_mut() {
 489            cx.scene.push_stacking_context(None);
 490
 491            let cursor_row_layout = &layout.line_layouts[(position.row() - start_row) as usize];
 492            let x = cursor_row_layout.x_for_index(position.column() as usize) - scroll_left;
 493            let y = (position.row() + 1) as f32 * layout.line_height - scroll_top;
 494            let mut list_origin = content_origin + vec2f(x, y);
 495            let list_width = context_menu.size().x();
 496            let list_height = context_menu.size().y();
 497
 498            // Snap the right edge of the list to the right edge of the window if
 499            // its horizontal bounds overflow.
 500            if list_origin.x() + list_width > cx.window_size.x() {
 501                list_origin.set_x((cx.window_size.x() - list_width).max(0.));
 502            }
 503
 504            if list_origin.y() + list_height > bounds.max_y() {
 505                list_origin.set_y(list_origin.y() - layout.line_height - list_height);
 506            }
 507
 508            context_menu.paint(
 509                list_origin,
 510                RectF::from_points(Vector2F::zero(), vec2f(f32::MAX, f32::MAX)), // Let content bleed outside of editor
 511                cx,
 512            );
 513
 514            cx.scene.pop_stacking_context();
 515        }
 516
 517        if let Some((position, hover_popover)) = layout.hover.as_mut() {
 518            cx.scene.push_stacking_context(None);
 519
 520            // This is safe because we check on layout whether the required row is available
 521            let hovered_row_layout = &layout.line_layouts[(position.row() - start_row) as usize];
 522            let size = hover_popover.size();
 523            let x = hovered_row_layout.x_for_index(position.column() as usize) - scroll_left;
 524            let y = position.row() as f32 * layout.line_height - scroll_top - size.y();
 525            let mut popover_origin = content_origin + vec2f(x, y);
 526
 527            if popover_origin.y() < 0.0 {
 528                popover_origin.set_y(popover_origin.y() + layout.line_height + size.y());
 529            }
 530
 531            let x_out_of_bounds = bounds.max_x() - (popover_origin.x() + size.x());
 532            if x_out_of_bounds < 0.0 {
 533                popover_origin.set_x(popover_origin.x() + x_out_of_bounds);
 534            }
 535
 536            hover_popover.paint(
 537                popover_origin,
 538                RectF::from_points(Vector2F::zero(), vec2f(f32::MAX, f32::MAX)), // Let content bleed outside of editor
 539                cx,
 540            );
 541
 542            paint.hover_bounds = Some(
 543                RectF::new(popover_origin, hover_popover.size()).dilate(Vector2F::new(0., 5.)),
 544            );
 545
 546            cx.scene.pop_stacking_context();
 547        }
 548
 549        cx.scene.pop_layer();
 550    }
 551
 552    fn paint_highlighted_range(
 553        &self,
 554        range: Range<DisplayPoint>,
 555        start_row: u32,
 556        end_row: u32,
 557        color: Color,
 558        corner_radius: f32,
 559        line_end_overshoot: f32,
 560        layout: &LayoutState,
 561        content_origin: Vector2F,
 562        scroll_top: f32,
 563        scroll_left: f32,
 564        bounds: RectF,
 565        cx: &mut PaintContext,
 566    ) {
 567        if range.start != range.end {
 568            let row_range = if range.end.column() == 0 {
 569                cmp::max(range.start.row(), start_row)..cmp::min(range.end.row(), end_row)
 570            } else {
 571                cmp::max(range.start.row(), start_row)..cmp::min(range.end.row() + 1, end_row)
 572            };
 573
 574            let highlighted_range = HighlightedRange {
 575                color,
 576                line_height: layout.line_height,
 577                corner_radius,
 578                start_y: content_origin.y() + row_range.start as f32 * layout.line_height
 579                    - scroll_top,
 580                lines: row_range
 581                    .into_iter()
 582                    .map(|row| {
 583                        let line_layout = &layout.line_layouts[(row - start_row) as usize];
 584                        HighlightedRangeLine {
 585                            start_x: if row == range.start.row() {
 586                                content_origin.x()
 587                                    + line_layout.x_for_index(range.start.column() as usize)
 588                                    - scroll_left
 589                            } else {
 590                                content_origin.x() - scroll_left
 591                            },
 592                            end_x: if row == range.end.row() {
 593                                content_origin.x()
 594                                    + line_layout.x_for_index(range.end.column() as usize)
 595                                    - scroll_left
 596                            } else {
 597                                content_origin.x() + line_layout.width() + line_end_overshoot
 598                                    - scroll_left
 599                            },
 600                        }
 601                    })
 602                    .collect(),
 603            };
 604
 605            highlighted_range.paint(bounds, cx.scene);
 606        }
 607    }
 608
 609    fn paint_blocks(
 610        &mut self,
 611        bounds: RectF,
 612        visible_bounds: RectF,
 613        layout: &mut LayoutState,
 614        cx: &mut PaintContext,
 615    ) {
 616        let scroll_position = layout.snapshot.scroll_position();
 617        let scroll_left = scroll_position.x() * layout.em_width;
 618        let scroll_top = scroll_position.y() * layout.line_height;
 619
 620        for (row, element) in &mut layout.blocks {
 621            let origin = bounds.origin()
 622                + vec2f(-scroll_left, *row as f32 * layout.line_height - scroll_top);
 623            element.paint(origin, visible_bounds, cx);
 624        }
 625    }
 626
 627    fn max_line_number_width(&self, snapshot: &EditorSnapshot, cx: &LayoutContext) -> f32 {
 628        let digit_count = (snapshot.max_buffer_row() as f32).log10().floor() as usize + 1;
 629        let style = &self.style;
 630
 631        cx.text_layout_cache
 632            .layout_str(
 633                "1".repeat(digit_count).as_str(),
 634                style.text.font_size,
 635                &[(
 636                    digit_count,
 637                    RunStyle {
 638                        font_id: style.text.font_id,
 639                        color: Color::black(),
 640                        underline: Default::default(),
 641                    },
 642                )],
 643            )
 644            .width()
 645    }
 646
 647    fn layout_line_numbers(
 648        &self,
 649        rows: Range<u32>,
 650        active_rows: &BTreeMap<u32, bool>,
 651        snapshot: &EditorSnapshot,
 652        cx: &LayoutContext,
 653    ) -> Vec<Option<text_layout::Line>> {
 654        let style = &self.style;
 655        let include_line_numbers = snapshot.mode == EditorMode::Full;
 656        let mut line_number_layouts = Vec::with_capacity(rows.len());
 657        let mut line_number = String::new();
 658        for (ix, row) in snapshot
 659            .buffer_rows(rows.start)
 660            .take((rows.end - rows.start) as usize)
 661            .enumerate()
 662        {
 663            let display_row = rows.start + ix as u32;
 664            let color = if active_rows.contains_key(&display_row) {
 665                style.line_number_active
 666            } else {
 667                style.line_number
 668            };
 669            if let Some(buffer_row) = row {
 670                if include_line_numbers {
 671                    line_number.clear();
 672                    write!(&mut line_number, "{}", buffer_row + 1).unwrap();
 673                    line_number_layouts.push(Some(cx.text_layout_cache.layout_str(
 674                        &line_number,
 675                        style.text.font_size,
 676                        &[(
 677                            line_number.len(),
 678                            RunStyle {
 679                                font_id: style.text.font_id,
 680                                color,
 681                                underline: Default::default(),
 682                            },
 683                        )],
 684                    )));
 685                }
 686            } else {
 687                line_number_layouts.push(None);
 688            }
 689        }
 690
 691        line_number_layouts
 692    }
 693
 694    fn layout_lines(
 695        &mut self,
 696        rows: Range<u32>,
 697        snapshot: &EditorSnapshot,
 698        cx: &LayoutContext,
 699    ) -> Vec<text_layout::Line> {
 700        if rows.start >= rows.end {
 701            return Vec::new();
 702        }
 703
 704        // When the editor is empty and unfocused, then show the placeholder.
 705        if snapshot.is_empty() && !snapshot.is_focused() {
 706            let placeholder_style = self
 707                .style
 708                .placeholder_text
 709                .as_ref()
 710                .unwrap_or_else(|| &self.style.text);
 711            let placeholder_text = snapshot.placeholder_text();
 712            let placeholder_lines = placeholder_text
 713                .as_ref()
 714                .map_or("", AsRef::as_ref)
 715                .split('\n')
 716                .skip(rows.start as usize)
 717                .chain(iter::repeat(""))
 718                .take(rows.len());
 719            return placeholder_lines
 720                .map(|line| {
 721                    cx.text_layout_cache.layout_str(
 722                        line,
 723                        placeholder_style.font_size,
 724                        &[(
 725                            line.len(),
 726                            RunStyle {
 727                                font_id: placeholder_style.font_id,
 728                                color: placeholder_style.color,
 729                                underline: Default::default(),
 730                            },
 731                        )],
 732                    )
 733                })
 734                .collect();
 735        } else {
 736            let style = &self.style;
 737            let chunks = snapshot.chunks(rows.clone(), true).map(|chunk| {
 738                let mut highlight_style = chunk
 739                    .syntax_highlight_id
 740                    .and_then(|id| id.style(&style.syntax));
 741
 742                if let Some(chunk_highlight) = chunk.highlight_style {
 743                    if let Some(highlight_style) = highlight_style.as_mut() {
 744                        highlight_style.highlight(chunk_highlight);
 745                    } else {
 746                        highlight_style = Some(chunk_highlight);
 747                    }
 748                }
 749
 750                let mut diagnostic_highlight = HighlightStyle::default();
 751
 752                if chunk.is_unnecessary {
 753                    diagnostic_highlight.fade_out = Some(style.unnecessary_code_fade);
 754                }
 755
 756                if let Some(severity) = chunk.diagnostic_severity {
 757                    // Omit underlines for HINT/INFO diagnostics on 'unnecessary' code.
 758                    if severity <= DiagnosticSeverity::WARNING || !chunk.is_unnecessary {
 759                        let diagnostic_style = super::diagnostic_style(severity, true, style);
 760                        diagnostic_highlight.underline = Some(Underline {
 761                            color: Some(diagnostic_style.message.text.color),
 762                            thickness: 1.0.into(),
 763                            squiggly: true,
 764                        });
 765                    }
 766                }
 767
 768                if let Some(highlight_style) = highlight_style.as_mut() {
 769                    highlight_style.highlight(diagnostic_highlight);
 770                } else {
 771                    highlight_style = Some(diagnostic_highlight);
 772                }
 773
 774                (chunk.text, highlight_style)
 775            });
 776            layout_highlighted_chunks(
 777                chunks,
 778                &style.text,
 779                &cx.text_layout_cache,
 780                &cx.font_cache,
 781                MAX_LINE_LEN,
 782                rows.len() as usize,
 783            )
 784        }
 785    }
 786
 787    fn layout_blocks(
 788        &mut self,
 789        rows: Range<u32>,
 790        snapshot: &EditorSnapshot,
 791        width: f32,
 792        gutter_padding: f32,
 793        gutter_width: f32,
 794        em_width: f32,
 795        text_x: f32,
 796        line_height: f32,
 797        style: &EditorStyle,
 798        line_layouts: &[text_layout::Line],
 799        cx: &mut LayoutContext,
 800    ) -> Vec<(u32, ElementBox)> {
 801        let editor = if let Some(editor) = self.view.upgrade(cx) {
 802            editor
 803        } else {
 804            return Default::default();
 805        };
 806
 807        let tooltip_style = cx.global::<Settings>().theme.tooltip.clone();
 808        let scroll_x = snapshot.scroll_position.x();
 809        snapshot
 810            .blocks_in_range(rows.clone())
 811            .map(|(block_row, block)| {
 812                let mut element = match block {
 813                    TransformBlock::Custom(block) => {
 814                        let align_to = block
 815                            .position()
 816                            .to_point(&snapshot.buffer_snapshot)
 817                            .to_display_point(snapshot);
 818                        let anchor_x = text_x
 819                            + if rows.contains(&align_to.row()) {
 820                                line_layouts[(align_to.row() - rows.start) as usize]
 821                                    .x_for_index(align_to.column() as usize)
 822                            } else {
 823                                layout_line(align_to.row(), snapshot, style, cx.text_layout_cache)
 824                                    .x_for_index(align_to.column() as usize)
 825                            };
 826
 827                        cx.render(&editor, |_, cx| {
 828                            block.render(&mut BlockContext {
 829                                cx,
 830                                anchor_x,
 831                                gutter_padding,
 832                                line_height,
 833                                scroll_x,
 834                                gutter_width,
 835                                em_width,
 836                            })
 837                        })
 838                    }
 839                    TransformBlock::ExcerptHeader {
 840                        key,
 841                        buffer,
 842                        range,
 843                        starts_new_buffer,
 844                        ..
 845                    } => {
 846                        let jump_icon = project::File::from_dyn(buffer.file()).map(|file| {
 847                            let jump_position = range
 848                                .primary
 849                                .as_ref()
 850                                .map_or(range.context.start, |primary| primary.start);
 851                            let jump_action = crate::Jump {
 852                                path: ProjectPath {
 853                                    worktree_id: file.worktree_id(cx),
 854                                    path: file.path.clone(),
 855                                },
 856                                position: language::ToPoint::to_point(&jump_position, buffer),
 857                                anchor: jump_position,
 858                            };
 859
 860                            enum JumpIcon {}
 861                            cx.render(&editor, |_, cx| {
 862                                MouseEventHandler::new::<JumpIcon, _, _>(*key, cx, |state, _| {
 863                                    let style = style.jump_icon.style_for(state, false);
 864                                    Svg::new("icons/jump.svg")
 865                                        .with_color(style.color)
 866                                        .constrained()
 867                                        .with_width(style.icon_width)
 868                                        .aligned()
 869                                        .contained()
 870                                        .with_style(style.container)
 871                                        .constrained()
 872                                        .with_width(style.button_width)
 873                                        .with_height(style.button_width)
 874                                        .boxed()
 875                                })
 876                                .with_cursor_style(CursorStyle::PointingHand)
 877                                .on_click({
 878                                    move |_, _, cx| cx.dispatch_action(jump_action.clone())
 879                                })
 880                                .with_tooltip(
 881                                    *key,
 882                                    "Jump to Buffer".to_string(),
 883                                    Some(Box::new(crate::OpenExcerpts)),
 884                                    tooltip_style.clone(),
 885                                    cx,
 886                                )
 887                                .aligned()
 888                                .flex_float()
 889                                .boxed()
 890                            })
 891                        });
 892
 893                        let padding = gutter_padding + scroll_x * em_width;
 894                        if *starts_new_buffer {
 895                            let style = &self.style.diagnostic_path_header;
 896                            let font_size =
 897                                (style.text_scale_factor * self.style.text.font_size).round();
 898
 899                            let mut filename = None;
 900                            let mut parent_path = None;
 901                            if let Some(file) = buffer.file() {
 902                                let path = file.path();
 903                                filename =
 904                                    path.file_name().map(|f| f.to_string_lossy().to_string());
 905                                parent_path =
 906                                    path.parent().map(|p| p.to_string_lossy().to_string() + "/");
 907                            }
 908
 909                            Flex::row()
 910                                .with_child(
 911                                    Label::new(
 912                                        filename.unwrap_or_else(|| "untitled".to_string()),
 913                                        style.filename.text.clone().with_font_size(font_size),
 914                                    )
 915                                    .contained()
 916                                    .with_style(style.filename.container)
 917                                    .aligned()
 918                                    .boxed(),
 919                                )
 920                                .with_children(parent_path.map(|path| {
 921                                    Label::new(
 922                                        path,
 923                                        style.path.text.clone().with_font_size(font_size),
 924                                    )
 925                                    .contained()
 926                                    .with_style(style.path.container)
 927                                    .aligned()
 928                                    .boxed()
 929                                }))
 930                                .with_children(jump_icon)
 931                                .contained()
 932                                .with_style(style.container)
 933                                .with_padding_left(padding)
 934                                .with_padding_right(padding)
 935                                .expanded()
 936                                .named("path header block")
 937                        } else {
 938                            let text_style = self.style.text.clone();
 939                            Flex::row()
 940                                .with_child(Label::new("".to_string(), text_style).boxed())
 941                                .with_children(jump_icon)
 942                                .contained()
 943                                .with_padding_left(padding)
 944                                .with_padding_right(padding)
 945                                .expanded()
 946                                .named("collapsed context")
 947                        }
 948                    }
 949                };
 950
 951                element.layout(
 952                    SizeConstraint {
 953                        min: Vector2F::zero(),
 954                        max: vec2f(width, block.height() as f32 * line_height),
 955                    },
 956                    cx,
 957                );
 958                (block_row, element)
 959            })
 960            .collect()
 961    }
 962}
 963
 964impl Element for EditorElement {
 965    type LayoutState = LayoutState;
 966    type PaintState = PaintState;
 967
 968    fn layout(
 969        &mut self,
 970        constraint: SizeConstraint,
 971        cx: &mut LayoutContext,
 972    ) -> (Vector2F, Self::LayoutState) {
 973        let mut size = constraint.max;
 974        if size.x().is_infinite() {
 975            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 976        }
 977
 978        let snapshot = self.snapshot(cx.app);
 979        let style = self.style.clone();
 980        let line_height = style.text.line_height(cx.font_cache);
 981
 982        let gutter_padding;
 983        let gutter_width;
 984        let gutter_margin;
 985        if snapshot.mode == EditorMode::Full {
 986            gutter_padding = style.text.em_width(cx.font_cache) * style.gutter_padding_factor;
 987            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 988            gutter_margin = -style.text.descent(cx.font_cache);
 989        } else {
 990            gutter_padding = 0.0;
 991            gutter_width = 0.0;
 992            gutter_margin = 0.0;
 993        };
 994
 995        let text_width = size.x() - gutter_width;
 996        let em_width = style.text.em_width(cx.font_cache);
 997        let em_advance = style.text.em_advance(cx.font_cache);
 998        let overscroll = vec2f(em_width, 0.);
 999        let snapshot = self.update_view(cx.app, |view, cx| {
1000            let wrap_width = match view.soft_wrap_mode(cx) {
1001                SoftWrap::None => Some((MAX_LINE_LEN / 2) as f32 * em_advance),
1002                SoftWrap::EditorWidth => {
1003                    Some(text_width - gutter_margin - overscroll.x() - em_width)
1004                }
1005                SoftWrap::Column(column) => Some(column as f32 * em_advance),
1006            };
1007
1008            if view.set_wrap_width(wrap_width, cx) {
1009                view.snapshot(cx)
1010            } else {
1011                snapshot
1012            }
1013        });
1014
1015        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
1016        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
1017            size.set_y(
1018                scroll_height
1019                    .min(constraint.max_along(Axis::Vertical))
1020                    .max(constraint.min_along(Axis::Vertical))
1021                    .min(line_height * max_lines as f32),
1022            )
1023        } else if let EditorMode::SingleLine = snapshot.mode {
1024            size.set_y(
1025                line_height
1026                    .min(constraint.max_along(Axis::Vertical))
1027                    .max(constraint.min_along(Axis::Vertical)),
1028            )
1029        } else if size.y().is_infinite() {
1030            size.set_y(scroll_height);
1031        }
1032        let gutter_size = vec2f(gutter_width, size.y());
1033        let text_size = vec2f(text_width, size.y());
1034
1035        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
1036            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
1037            let snapshot = view.snapshot(cx);
1038            (autoscroll_horizontally, snapshot)
1039        });
1040
1041        let scroll_position = snapshot.scroll_position();
1042        let start_row = scroll_position.y() as u32;
1043        let scroll_top = scroll_position.y() * line_height;
1044
1045        // Add 1 to ensure selections bleed off screen
1046        let end_row = 1 + cmp::min(
1047            ((scroll_top + size.y()) / line_height).ceil() as u32,
1048            snapshot.max_point().row(),
1049        );
1050
1051        let start_anchor = if start_row == 0 {
1052            Anchor::min()
1053        } else {
1054            snapshot
1055                .buffer_snapshot
1056                .anchor_before(DisplayPoint::new(start_row, 0).to_offset(&snapshot, Bias::Left))
1057        };
1058        let end_anchor = if end_row > snapshot.max_point().row() {
1059            Anchor::max()
1060        } else {
1061            snapshot
1062                .buffer_snapshot
1063                .anchor_before(DisplayPoint::new(end_row, 0).to_offset(&snapshot, Bias::Right))
1064        };
1065
1066        let mut selections: Vec<(ReplicaId, Vec<SelectionLayout>)> = Vec::new();
1067        let mut active_rows = BTreeMap::new();
1068        let mut highlighted_rows = None;
1069        let mut highlighted_ranges = Vec::new();
1070        self.update_view(cx.app, |view, cx| {
1071            let display_map = view.display_map.update(cx, |map, cx| map.snapshot(cx));
1072
1073            highlighted_rows = view.highlighted_rows();
1074            let theme = cx.global::<Settings>().theme.as_ref();
1075            highlighted_ranges = view.background_highlights_in_range(
1076                start_anchor.clone()..end_anchor.clone(),
1077                &display_map,
1078                theme,
1079            );
1080
1081            let mut remote_selections = HashMap::default();
1082            for (replica_id, line_mode, selection) in display_map
1083                .buffer_snapshot
1084                .remote_selections_in_range(&(start_anchor.clone()..end_anchor.clone()))
1085            {
1086                // The local selections match the leader's selections.
1087                if Some(replica_id) == view.leader_replica_id {
1088                    continue;
1089                }
1090                remote_selections
1091                    .entry(replica_id)
1092                    .or_insert(Vec::new())
1093                    .push(SelectionLayout::new(selection, line_mode, &display_map));
1094            }
1095            selections.extend(remote_selections);
1096
1097            if view.show_local_selections {
1098                let mut local_selections = view
1099                    .selections
1100                    .disjoint_in_range(start_anchor..end_anchor, cx);
1101                local_selections.extend(view.selections.pending(cx));
1102                for selection in &local_selections {
1103                    let is_empty = selection.start == selection.end;
1104                    let selection_start = snapshot.prev_line_boundary(selection.start).1;
1105                    let selection_end = snapshot.next_line_boundary(selection.end).1;
1106                    for row in cmp::max(selection_start.row(), start_row)
1107                        ..=cmp::min(selection_end.row(), end_row)
1108                    {
1109                        let contains_non_empty_selection =
1110                            active_rows.entry(row).or_insert(!is_empty);
1111                        *contains_non_empty_selection |= !is_empty;
1112                    }
1113                }
1114
1115                // Render the local selections in the leader's color when following.
1116                let local_replica_id = view.leader_replica_id.unwrap_or(view.replica_id(cx));
1117
1118                selections.push((
1119                    local_replica_id,
1120                    local_selections
1121                        .into_iter()
1122                        .map(|selection| {
1123                            SelectionLayout::new(selection, view.selections.line_mode, &display_map)
1124                        })
1125                        .collect(),
1126                ));
1127            }
1128        });
1129
1130        let line_number_layouts =
1131            self.layout_line_numbers(start_row..end_row, &active_rows, &snapshot, cx);
1132
1133        let mut max_visible_line_width = 0.0;
1134        let line_layouts = self.layout_lines(start_row..end_row, &snapshot, cx);
1135        for line in &line_layouts {
1136            if line.width() > max_visible_line_width {
1137                max_visible_line_width = line.width();
1138            }
1139        }
1140
1141        let style = self.style.clone();
1142        let longest_line_width = layout_line(
1143            snapshot.longest_row(),
1144            &snapshot,
1145            &style,
1146            cx.text_layout_cache,
1147        )
1148        .width();
1149        let scroll_width = longest_line_width.max(max_visible_line_width) + overscroll.x();
1150        let em_width = style.text.em_width(cx.font_cache);
1151        let max_row = snapshot.max_point().row();
1152        let scroll_max = vec2f(
1153            ((scroll_width - text_size.x()) / em_width).max(0.0),
1154            max_row.saturating_sub(1) as f32,
1155        );
1156
1157        self.update_view(cx.app, |view, cx| {
1158            let clamped = view.clamp_scroll_left(scroll_max.x());
1159            let autoscrolled;
1160            if autoscroll_horizontally {
1161                autoscrolled = view.autoscroll_horizontally(
1162                    start_row,
1163                    text_size.x(),
1164                    scroll_width,
1165                    em_width,
1166                    &line_layouts,
1167                    cx,
1168                );
1169            } else {
1170                autoscrolled = false;
1171            }
1172
1173            if clamped || autoscrolled {
1174                snapshot = view.snapshot(cx);
1175            }
1176        });
1177
1178        let mut context_menu = None;
1179        let mut code_actions_indicator = None;
1180        let mut hover = None;
1181        cx.render(&self.view.upgrade(cx).unwrap(), |view, cx| {
1182            let newest_selection_head = view
1183                .selections
1184                .newest::<usize>(cx)
1185                .head()
1186                .to_display_point(&snapshot);
1187
1188            let style = view.style(cx);
1189            if (start_row..end_row).contains(&newest_selection_head.row()) {
1190                if view.context_menu_visible() {
1191                    context_menu =
1192                        view.render_context_menu(newest_selection_head, style.clone(), cx);
1193                }
1194
1195                code_actions_indicator = view
1196                    .render_code_actions_indicator(&style, cx)
1197                    .map(|indicator| (newest_selection_head.row(), indicator));
1198            }
1199
1200            hover = view.hover_state.popover.clone().and_then(|hover| {
1201                let (point, rendered) = hover.render(&snapshot, style.clone(), cx);
1202                if point.row() >= snapshot.scroll_position().y() as u32 {
1203                    if line_layouts.len() > (point.row() - start_row) as usize {
1204                        return Some((point, rendered));
1205                    }
1206                }
1207
1208                None
1209            });
1210        });
1211
1212        if let Some((_, context_menu)) = context_menu.as_mut() {
1213            context_menu.layout(
1214                SizeConstraint {
1215                    min: Vector2F::zero(),
1216                    max: vec2f(
1217                        f32::INFINITY,
1218                        (12. * line_height).min((size.y() - line_height) / 2.),
1219                    ),
1220                },
1221                cx,
1222            );
1223        }
1224
1225        if let Some((_, indicator)) = code_actions_indicator.as_mut() {
1226            indicator.layout(
1227                SizeConstraint::strict_along(Axis::Vertical, line_height * 0.618),
1228                cx,
1229            );
1230        }
1231
1232        if let Some((_, hover)) = hover.as_mut() {
1233            hover.layout(
1234                SizeConstraint {
1235                    min: Vector2F::zero(),
1236                    max: vec2f(
1237                        (120. * em_width) // Default size
1238                            .min(size.x() / 2.) // Shrink to half of the editor width
1239                            .max(20. * em_width), // Apply minimum width of 20 characters
1240                        (16. * line_height) // Default size
1241                            .min(size.y() / 2.) // Shrink to half of the editor height
1242                            .max(4. * line_height), // Apply minimum height of 4 lines
1243                    ),
1244                },
1245                cx,
1246            );
1247        }
1248
1249        let blocks = self.layout_blocks(
1250            start_row..end_row,
1251            &snapshot,
1252            size.x().max(scroll_width + gutter_width),
1253            gutter_padding,
1254            gutter_width,
1255            em_width,
1256            gutter_width + gutter_margin,
1257            line_height,
1258            &style,
1259            &line_layouts,
1260            cx,
1261        );
1262
1263        (
1264            size,
1265            LayoutState {
1266                size,
1267                scroll_max,
1268                gutter_size,
1269                gutter_padding,
1270                text_size,
1271                gutter_margin,
1272                snapshot,
1273                active_rows,
1274                highlighted_rows,
1275                highlighted_ranges,
1276                line_layouts,
1277                line_number_layouts,
1278                blocks,
1279                line_height,
1280                em_width,
1281                em_advance,
1282                selections,
1283                context_menu,
1284                code_actions_indicator,
1285                hover,
1286            },
1287        )
1288    }
1289
1290    fn paint(
1291        &mut self,
1292        bounds: RectF,
1293        visible_bounds: RectF,
1294        layout: &mut Self::LayoutState,
1295        cx: &mut PaintContext,
1296    ) -> Self::PaintState {
1297        cx.scene.push_layer(Some(bounds));
1298
1299        let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
1300        let text_bounds = RectF::new(
1301            bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
1302            layout.text_size,
1303        );
1304
1305        let mut paint_state = PaintState {
1306            bounds,
1307            gutter_bounds,
1308            text_bounds,
1309            hover_bounds: None,
1310        };
1311
1312        self.paint_background(gutter_bounds, text_bounds, layout, cx);
1313        if layout.gutter_size.x() > 0. {
1314            self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
1315        }
1316        self.paint_text(text_bounds, visible_bounds, layout, &mut paint_state, cx);
1317
1318        if !layout.blocks.is_empty() {
1319            cx.scene.push_layer(Some(bounds));
1320            self.paint_blocks(bounds, visible_bounds, layout, cx);
1321            cx.scene.pop_layer();
1322        }
1323
1324        cx.scene.pop_layer();
1325
1326        paint_state
1327    }
1328
1329    fn dispatch_event(
1330        &mut self,
1331        event: &Event,
1332        _: RectF,
1333        _: RectF,
1334        layout: &mut LayoutState,
1335        paint: &mut PaintState,
1336        cx: &mut EventContext,
1337    ) -> bool {
1338        if let Some((_, context_menu)) = &mut layout.context_menu {
1339            if context_menu.dispatch_event(event, cx) {
1340                return true;
1341            }
1342        }
1343
1344        if let Some((_, indicator)) = &mut layout.code_actions_indicator {
1345            if indicator.dispatch_event(event, cx) {
1346                return true;
1347            }
1348        }
1349
1350        if let Some((_, hover)) = &mut layout.hover {
1351            if hover.dispatch_event(event, cx) {
1352                return true;
1353            }
1354        }
1355
1356        for (_, block) in &mut layout.blocks {
1357            if block.dispatch_event(event, cx) {
1358                return true;
1359            }
1360        }
1361
1362        match event {
1363            Event::LeftMouseDown {
1364                position,
1365                cmd,
1366                alt,
1367                shift,
1368                click_count,
1369                ..
1370            } => self.mouse_down(
1371                *position,
1372                *cmd,
1373                *alt,
1374                *shift,
1375                *click_count,
1376                layout,
1377                paint,
1378                cx,
1379            ),
1380            Event::LeftMouseUp { position, .. } => self.mouse_up(*position, cx),
1381            Event::LeftMouseDragged { position } => {
1382                self.mouse_dragged(*position, layout, paint, cx)
1383            }
1384            Event::ScrollWheel {
1385                position,
1386                delta,
1387                precise,
1388            } => self.scroll(*position, *delta, *precise, layout, paint, cx),
1389            Event::KeyDown { input, .. } => self.key_down(input.as_deref(), cx),
1390            Event::MouseMoved { position, .. } => {
1391                if paint
1392                    .hover_bounds
1393                    .map_or(false, |hover_bounds| hover_bounds.contains_point(*position))
1394                {
1395                    return false;
1396                }
1397
1398                let point = if paint.text_bounds.contains_point(*position) {
1399                    let (point, overshoot) =
1400                        paint.point_for_position(&self.snapshot(cx), layout, *position);
1401                    if overshoot.is_zero() {
1402                        Some(point)
1403                    } else {
1404                        None
1405                    }
1406                } else {
1407                    None
1408                };
1409
1410                cx.dispatch_action(HoverAt { point });
1411                true
1412            }
1413            _ => false,
1414        }
1415    }
1416
1417    fn debug(
1418        &self,
1419        bounds: RectF,
1420        _: &Self::LayoutState,
1421        _: &Self::PaintState,
1422        _: &gpui::DebugContext,
1423    ) -> json::Value {
1424        json!({
1425            "type": "BufferElement",
1426            "bounds": bounds.to_json()
1427        })
1428    }
1429}
1430
1431pub struct LayoutState {
1432    size: Vector2F,
1433    scroll_max: Vector2F,
1434    gutter_size: Vector2F,
1435    gutter_padding: f32,
1436    gutter_margin: f32,
1437    text_size: Vector2F,
1438    snapshot: EditorSnapshot,
1439    active_rows: BTreeMap<u32, bool>,
1440    highlighted_rows: Option<Range<u32>>,
1441    line_layouts: Vec<text_layout::Line>,
1442    line_number_layouts: Vec<Option<text_layout::Line>>,
1443    blocks: Vec<(u32, ElementBox)>,
1444    line_height: f32,
1445    em_width: f32,
1446    em_advance: f32,
1447    highlighted_ranges: Vec<(Range<DisplayPoint>, Color)>,
1448    selections: Vec<(ReplicaId, Vec<SelectionLayout>)>,
1449    context_menu: Option<(DisplayPoint, ElementBox)>,
1450    code_actions_indicator: Option<(u32, ElementBox)>,
1451    hover: Option<(DisplayPoint, ElementBox)>,
1452}
1453
1454fn layout_line(
1455    row: u32,
1456    snapshot: &EditorSnapshot,
1457    style: &EditorStyle,
1458    layout_cache: &TextLayoutCache,
1459) -> text_layout::Line {
1460    let mut line = snapshot.line(row);
1461
1462    if line.len() > MAX_LINE_LEN {
1463        let mut len = MAX_LINE_LEN;
1464        while !line.is_char_boundary(len) {
1465            len -= 1;
1466        }
1467
1468        line.truncate(len);
1469    }
1470
1471    layout_cache.layout_str(
1472        &line,
1473        style.text.font_size,
1474        &[(
1475            snapshot.line_len(row) as usize,
1476            RunStyle {
1477                font_id: style.text.font_id,
1478                color: Color::black(),
1479                underline: Default::default(),
1480            },
1481        )],
1482    )
1483}
1484
1485pub struct PaintState {
1486    bounds: RectF,
1487    gutter_bounds: RectF,
1488    text_bounds: RectF,
1489    hover_bounds: Option<RectF>,
1490}
1491
1492impl PaintState {
1493    /// Returns two display points. The first is the nearest valid
1494    /// position in the current buffer and the second is the distance to the
1495    /// nearest valid position if there was overshoot.
1496    fn point_for_position(
1497        &self,
1498        snapshot: &EditorSnapshot,
1499        layout: &LayoutState,
1500        position: Vector2F,
1501    ) -> (DisplayPoint, DisplayPoint) {
1502        let scroll_position = snapshot.scroll_position();
1503        let position = position - self.text_bounds.origin();
1504        let y = position.y().max(0.0).min(layout.size.y());
1505        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
1506        let row_overshoot = row.saturating_sub(snapshot.max_point().row());
1507        let row = cmp::min(row, snapshot.max_point().row());
1508        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
1509        let x = position.x() + (scroll_position.x() * layout.em_width);
1510
1511        let column = if x >= 0.0 {
1512            line.index_for_x(x)
1513                .map(|ix| ix as u32)
1514                .unwrap_or_else(|| snapshot.line_len(row))
1515        } else {
1516            0
1517        };
1518        let column_overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
1519
1520        (
1521            DisplayPoint::new(row, column),
1522            DisplayPoint::new(row_overshoot, column_overshoot),
1523        )
1524    }
1525}
1526
1527#[derive(Copy, Clone, PartialEq, Eq)]
1528pub enum CursorShape {
1529    Bar,
1530    Block,
1531    Underscore,
1532}
1533
1534impl Default for CursorShape {
1535    fn default() -> Self {
1536        CursorShape::Bar
1537    }
1538}
1539
1540struct Cursor {
1541    origin: Vector2F,
1542    block_width: f32,
1543    line_height: f32,
1544    color: Color,
1545    shape: CursorShape,
1546    block_text: Option<Line>,
1547}
1548
1549impl Cursor {
1550    fn paint(&self, cx: &mut PaintContext) {
1551        let bounds = match self.shape {
1552            CursorShape::Bar => RectF::new(self.origin, vec2f(2.0, self.line_height)),
1553            CursorShape::Block => {
1554                RectF::new(self.origin, vec2f(self.block_width, self.line_height))
1555            }
1556            CursorShape::Underscore => RectF::new(
1557                self.origin + Vector2F::new(0.0, self.line_height - 2.0),
1558                vec2f(self.block_width, 2.0),
1559            ),
1560        };
1561
1562        cx.scene.push_quad(Quad {
1563            bounds,
1564            background: Some(self.color),
1565            border: Border::new(0., Color::black()),
1566            corner_radius: 0.,
1567        });
1568
1569        if let Some(block_text) = &self.block_text {
1570            block_text.paint(self.origin, bounds, self.line_height, cx);
1571        }
1572    }
1573}
1574
1575#[derive(Debug)]
1576struct HighlightedRange {
1577    start_y: f32,
1578    line_height: f32,
1579    lines: Vec<HighlightedRangeLine>,
1580    color: Color,
1581    corner_radius: f32,
1582}
1583
1584#[derive(Debug)]
1585struct HighlightedRangeLine {
1586    start_x: f32,
1587    end_x: f32,
1588}
1589
1590impl HighlightedRange {
1591    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1592        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1593            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1594            self.paint_lines(
1595                self.start_y + self.line_height,
1596                &self.lines[1..],
1597                bounds,
1598                scene,
1599            );
1600        } else {
1601            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1602        }
1603    }
1604
1605    fn paint_lines(
1606        &self,
1607        start_y: f32,
1608        lines: &[HighlightedRangeLine],
1609        bounds: RectF,
1610        scene: &mut Scene,
1611    ) {
1612        if lines.is_empty() {
1613            return;
1614        }
1615
1616        let mut path = PathBuilder::new();
1617        let first_line = lines.first().unwrap();
1618        let last_line = lines.last().unwrap();
1619
1620        let first_top_left = vec2f(first_line.start_x, start_y);
1621        let first_top_right = vec2f(first_line.end_x, start_y);
1622
1623        let curve_height = vec2f(0., self.corner_radius);
1624        let curve_width = |start_x: f32, end_x: f32| {
1625            let max = (end_x - start_x) / 2.;
1626            let width = if max < self.corner_radius {
1627                max
1628            } else {
1629                self.corner_radius
1630            };
1631
1632            vec2f(width, 0.)
1633        };
1634
1635        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1636        path.reset(first_top_right - top_curve_width);
1637        path.curve_to(first_top_right + curve_height, first_top_right);
1638
1639        let mut iter = lines.iter().enumerate().peekable();
1640        while let Some((ix, line)) = iter.next() {
1641            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1642
1643            if let Some((_, next_line)) = iter.peek() {
1644                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1645
1646                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1647                    Ordering::Equal => {
1648                        path.line_to(bottom_right);
1649                    }
1650                    Ordering::Less => {
1651                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1652                        path.line_to(bottom_right - curve_height);
1653                        if self.corner_radius > 0. {
1654                            path.curve_to(bottom_right - curve_width, bottom_right);
1655                        }
1656                        path.line_to(next_top_right + curve_width);
1657                        if self.corner_radius > 0. {
1658                            path.curve_to(next_top_right + curve_height, next_top_right);
1659                        }
1660                    }
1661                    Ordering::Greater => {
1662                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1663                        path.line_to(bottom_right - curve_height);
1664                        if self.corner_radius > 0. {
1665                            path.curve_to(bottom_right + curve_width, bottom_right);
1666                        }
1667                        path.line_to(next_top_right - curve_width);
1668                        if self.corner_radius > 0. {
1669                            path.curve_to(next_top_right + curve_height, next_top_right);
1670                        }
1671                    }
1672                }
1673            } else {
1674                let curve_width = curve_width(line.start_x, line.end_x);
1675                path.line_to(bottom_right - curve_height);
1676                if self.corner_radius > 0. {
1677                    path.curve_to(bottom_right - curve_width, bottom_right);
1678                }
1679
1680                let bottom_left = vec2f(line.start_x, bottom_right.y());
1681                path.line_to(bottom_left + curve_width);
1682                if self.corner_radius > 0. {
1683                    path.curve_to(bottom_left - curve_height, bottom_left);
1684                }
1685            }
1686        }
1687
1688        if first_line.start_x > last_line.start_x {
1689            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1690            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1691            path.line_to(second_top_left + curve_height);
1692            if self.corner_radius > 0. {
1693                path.curve_to(second_top_left + curve_width, second_top_left);
1694            }
1695            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1696            path.line_to(first_bottom_left - curve_width);
1697            if self.corner_radius > 0. {
1698                path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1699            }
1700        }
1701
1702        path.line_to(first_top_left + curve_height);
1703        if self.corner_radius > 0. {
1704            path.curve_to(first_top_left + top_curve_width, first_top_left);
1705        }
1706        path.line_to(first_top_right - top_curve_width);
1707
1708        scene.push_path(path.build(self.color, Some(bounds)));
1709    }
1710}
1711
1712fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1713    delta.powf(1.5) / 100.0
1714}
1715
1716fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1717    delta.powf(1.2) / 300.0
1718}
1719
1720#[cfg(test)]
1721mod tests {
1722    use std::sync::Arc;
1723
1724    use super::*;
1725    use crate::{
1726        display_map::{BlockDisposition, BlockProperties},
1727        Editor, MultiBuffer,
1728    };
1729    use settings::Settings;
1730    use util::test::sample_text;
1731
1732    #[gpui::test]
1733    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1734        cx.set_global(Settings::test(cx));
1735        let buffer = MultiBuffer::build_simple(&sample_text(6, 6, 'a'), cx);
1736        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1737            Editor::new(EditorMode::Full, buffer, None, None, None, cx)
1738        });
1739        let element = EditorElement::new(
1740            editor.downgrade(),
1741            editor.read(cx).style(cx),
1742            CursorShape::Bar,
1743        );
1744
1745        let layouts = editor.update(cx, |editor, cx| {
1746            let snapshot = editor.snapshot(cx);
1747            let mut presenter = cx.build_presenter(window_id, 30.);
1748            let mut layout_cx = presenter.build_layout_context(Vector2F::zero(), false, cx);
1749            element.layout_line_numbers(0..6, &Default::default(), &snapshot, &mut layout_cx)
1750        });
1751        assert_eq!(layouts.len(), 6);
1752    }
1753
1754    #[gpui::test]
1755    fn test_layout_with_placeholder_text_and_blocks(cx: &mut gpui::MutableAppContext) {
1756        cx.set_global(Settings::test(cx));
1757        let buffer = MultiBuffer::build_simple("", cx);
1758        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1759            Editor::new(EditorMode::Full, buffer, None, None, None, cx)
1760        });
1761
1762        editor.update(cx, |editor, cx| {
1763            editor.set_placeholder_text("hello", cx);
1764            editor.insert_blocks(
1765                [BlockProperties {
1766                    disposition: BlockDisposition::Above,
1767                    height: 3,
1768                    position: Anchor::min(),
1769                    render: Arc::new(|_| Empty::new().boxed()),
1770                }],
1771                cx,
1772            );
1773
1774            // Blur the editor so that it displays placeholder text.
1775            cx.blur();
1776        });
1777
1778        let mut element = EditorElement::new(
1779            editor.downgrade(),
1780            editor.read(cx).style(cx),
1781            CursorShape::Bar,
1782        );
1783
1784        let mut scene = Scene::new(1.0);
1785        let mut presenter = cx.build_presenter(window_id, 30.);
1786        let mut layout_cx = presenter.build_layout_context(Vector2F::zero(), false, cx);
1787        let (size, mut state) = element.layout(
1788            SizeConstraint::new(vec2f(500., 500.), vec2f(500., 500.)),
1789            &mut layout_cx,
1790        );
1791
1792        assert_eq!(state.line_layouts.len(), 4);
1793        assert_eq!(
1794            state
1795                .line_number_layouts
1796                .iter()
1797                .map(Option::is_some)
1798                .collect::<Vec<_>>(),
1799            &[false, false, false, true]
1800        );
1801
1802        // Don't panic.
1803        let bounds = RectF::new(Default::default(), size);
1804        let mut paint_cx = presenter.build_paint_context(&mut scene, bounds.size(), cx);
1805        element.paint(bounds, bounds, &mut state, &mut paint_cx);
1806    }
1807}