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