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(path) = buffer.path() {
 842                                filename =
 843                                    path.file_name().map(|f| f.to_string_lossy().to_string());
 844                                parent_path =
 845                                    path.parent().map(|p| p.to_string_lossy().to_string() + "/");
 846                            }
 847
 848                            Flex::row()
 849                                .with_child(
 850                                    Label::new(
 851                                        filename.unwrap_or_else(|| "untitled".to_string()),
 852                                        style.filename.text.clone().with_font_size(font_size),
 853                                    )
 854                                    .contained()
 855                                    .with_style(style.filename.container)
 856                                    .boxed(),
 857                                )
 858                                .with_children(parent_path.map(|path| {
 859                                    Label::new(
 860                                        path,
 861                                        style.path.text.clone().with_font_size(font_size),
 862                                    )
 863                                    .contained()
 864                                    .with_style(style.path.container)
 865                                    .boxed()
 866                                }))
 867                                .aligned()
 868                                .left()
 869                                .contained()
 870                                .with_style(style.container)
 871                                .with_padding_left(gutter_padding + scroll_x * em_width)
 872                                .expanded()
 873                                .named("path header block")
 874                        } else {
 875                            let text_style = self.style.text.clone();
 876                            Label::new("".to_string(), text_style)
 877                                .contained()
 878                                .with_padding_left(gutter_padding + scroll_x * em_width)
 879                                .named("collapsed context")
 880                        }
 881                    }
 882                };
 883
 884                element.layout(
 885                    SizeConstraint {
 886                        min: Vector2F::zero(),
 887                        max: vec2f(width, block.height() as f32 * line_height),
 888                    },
 889                    cx,
 890                );
 891                (block_row, element)
 892            })
 893            .collect()
 894    }
 895}
 896
 897impl Element for EditorElement {
 898    type LayoutState = LayoutState;
 899    type PaintState = PaintState;
 900
 901    fn layout(
 902        &mut self,
 903        constraint: SizeConstraint,
 904        cx: &mut LayoutContext,
 905    ) -> (Vector2F, Self::LayoutState) {
 906        let mut size = constraint.max;
 907        if size.x().is_infinite() {
 908            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 909        }
 910
 911        let snapshot = self.snapshot(cx.app);
 912        let style = self.style.clone();
 913        let line_height = style.text.line_height(cx.font_cache);
 914
 915        let gutter_padding;
 916        let gutter_width;
 917        let gutter_margin;
 918        if snapshot.mode == EditorMode::Full {
 919            gutter_padding = style.text.em_width(cx.font_cache) * style.gutter_padding_factor;
 920            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 921            gutter_margin = -style.text.descent(cx.font_cache);
 922        } else {
 923            gutter_padding = 0.0;
 924            gutter_width = 0.0;
 925            gutter_margin = 0.0;
 926        };
 927
 928        let text_width = size.x() - gutter_width;
 929        let em_width = style.text.em_width(cx.font_cache);
 930        let em_advance = style.text.em_advance(cx.font_cache);
 931        let overscroll = vec2f(em_width, 0.);
 932        let snapshot = self.update_view(cx.app, |view, cx| {
 933            let wrap_width = match view.soft_wrap_mode(cx) {
 934                SoftWrap::None => Some((MAX_LINE_LEN / 2) as f32 * em_advance),
 935                SoftWrap::EditorWidth => {
 936                    Some(text_width - gutter_margin - overscroll.x() - em_width)
 937                }
 938                SoftWrap::Column(column) => Some(column as f32 * em_advance),
 939            };
 940
 941            if view.set_wrap_width(wrap_width, cx) {
 942                view.snapshot(cx)
 943            } else {
 944                snapshot
 945            }
 946        });
 947
 948        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
 949        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
 950            size.set_y(
 951                scroll_height
 952                    .min(constraint.max_along(Axis::Vertical))
 953                    .max(constraint.min_along(Axis::Vertical))
 954                    .min(line_height * max_lines as f32),
 955            )
 956        } else if let EditorMode::SingleLine = snapshot.mode {
 957            size.set_y(
 958                line_height
 959                    .min(constraint.max_along(Axis::Vertical))
 960                    .max(constraint.min_along(Axis::Vertical)),
 961            )
 962        } else if size.y().is_infinite() {
 963            size.set_y(scroll_height);
 964        }
 965        let gutter_size = vec2f(gutter_width, size.y());
 966        let text_size = vec2f(text_width, size.y());
 967
 968        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
 969            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
 970            let snapshot = view.snapshot(cx);
 971            (autoscroll_horizontally, snapshot)
 972        });
 973
 974        let scroll_position = snapshot.scroll_position();
 975        let start_row = scroll_position.y() as u32;
 976        let scroll_top = scroll_position.y() * line_height;
 977
 978        // Add 1 to ensure selections bleed off screen
 979        let end_row = 1 + cmp::min(
 980            ((scroll_top + size.y()) / line_height).ceil() as u32,
 981            snapshot.max_point().row(),
 982        );
 983
 984        let start_anchor = if start_row == 0 {
 985            Anchor::min()
 986        } else {
 987            snapshot
 988                .buffer_snapshot
 989                .anchor_before(DisplayPoint::new(start_row, 0).to_offset(&snapshot, Bias::Left))
 990        };
 991        let end_anchor = if end_row > snapshot.max_point().row() {
 992            Anchor::max()
 993        } else {
 994            snapshot
 995                .buffer_snapshot
 996                .anchor_before(DisplayPoint::new(end_row, 0).to_offset(&snapshot, Bias::Right))
 997        };
 998
 999        let mut selections: Vec<(ReplicaId, Vec<SelectionLayout>)> = Vec::new();
1000        let mut active_rows = BTreeMap::new();
1001        let mut highlighted_rows = None;
1002        let mut highlighted_ranges = Vec::new();
1003        self.update_view(cx.app, |view, cx| {
1004            let display_map = view.display_map.update(cx, |map, cx| map.snapshot(cx));
1005
1006            highlighted_rows = view.highlighted_rows();
1007            let theme = cx.global::<Settings>().theme.as_ref();
1008            highlighted_ranges = view.background_highlights_in_range(
1009                start_anchor.clone()..end_anchor.clone(),
1010                &display_map,
1011                theme,
1012            );
1013
1014            let mut remote_selections = HashMap::default();
1015            for (replica_id, line_mode, selection) in display_map
1016                .buffer_snapshot
1017                .remote_selections_in_range(&(start_anchor.clone()..end_anchor.clone()))
1018            {
1019                // The local selections match the leader's selections.
1020                if Some(replica_id) == view.leader_replica_id {
1021                    continue;
1022                }
1023                remote_selections
1024                    .entry(replica_id)
1025                    .or_insert(Vec::new())
1026                    .push(SelectionLayout::new(selection, line_mode, &display_map));
1027            }
1028            selections.extend(remote_selections);
1029
1030            if view.show_local_selections {
1031                let mut local_selections = view
1032                    .selections
1033                    .disjoint_in_range(start_anchor..end_anchor, cx);
1034                local_selections.extend(view.selections.pending(cx));
1035                for selection in &local_selections {
1036                    let is_empty = selection.start == selection.end;
1037                    let selection_start = snapshot.prev_line_boundary(selection.start).1;
1038                    let selection_end = snapshot.next_line_boundary(selection.end).1;
1039                    for row in cmp::max(selection_start.row(), start_row)
1040                        ..=cmp::min(selection_end.row(), end_row)
1041                    {
1042                        let contains_non_empty_selection =
1043                            active_rows.entry(row).or_insert(!is_empty);
1044                        *contains_non_empty_selection |= !is_empty;
1045                    }
1046                }
1047
1048                // Render the local selections in the leader's color when following.
1049                let local_replica_id = view.leader_replica_id.unwrap_or(view.replica_id(cx));
1050
1051                selections.push((
1052                    local_replica_id,
1053                    local_selections
1054                        .into_iter()
1055                        .map(|selection| {
1056                            SelectionLayout::new(selection, view.selections.line_mode, &display_map)
1057                        })
1058                        .collect(),
1059                ));
1060            }
1061        });
1062
1063        let line_number_layouts =
1064            self.layout_line_numbers(start_row..end_row, &active_rows, &snapshot, cx);
1065
1066        let mut max_visible_line_width = 0.0;
1067        let line_layouts = self.layout_lines(start_row..end_row, &snapshot, cx);
1068        for line in &line_layouts {
1069            if line.width() > max_visible_line_width {
1070                max_visible_line_width = line.width();
1071            }
1072        }
1073
1074        let style = self.style.clone();
1075        let longest_line_width = layout_line(
1076            snapshot.longest_row(),
1077            &snapshot,
1078            &style,
1079            cx.text_layout_cache,
1080        )
1081        .width();
1082        let scroll_width = longest_line_width.max(max_visible_line_width) + overscroll.x();
1083        let em_width = style.text.em_width(cx.font_cache);
1084        let max_row = snapshot.max_point().row();
1085        let scroll_max = vec2f(
1086            ((scroll_width - text_size.x()) / em_width).max(0.0),
1087            max_row.saturating_sub(1) as f32,
1088        );
1089
1090        self.update_view(cx.app, |view, cx| {
1091            let clamped = view.clamp_scroll_left(scroll_max.x());
1092            let autoscrolled;
1093            if autoscroll_horizontally {
1094                autoscrolled = view.autoscroll_horizontally(
1095                    start_row,
1096                    text_size.x(),
1097                    scroll_width,
1098                    em_width,
1099                    &line_layouts,
1100                    cx,
1101                );
1102            } else {
1103                autoscrolled = false;
1104            }
1105
1106            if clamped || autoscrolled {
1107                snapshot = view.snapshot(cx);
1108            }
1109        });
1110
1111        let mut context_menu = None;
1112        let mut code_actions_indicator = None;
1113        let mut hover = None;
1114        cx.render(&self.view.upgrade(cx).unwrap(), |view, cx| {
1115            let newest_selection_head = view
1116                .selections
1117                .newest::<usize>(cx)
1118                .head()
1119                .to_display_point(&snapshot);
1120
1121            let style = view.style(cx);
1122            if (start_row..end_row).contains(&newest_selection_head.row()) {
1123                if view.context_menu_visible() {
1124                    context_menu =
1125                        view.render_context_menu(newest_selection_head, style.clone(), cx);
1126                }
1127
1128                code_actions_indicator = view
1129                    .render_code_actions_indicator(&style, cx)
1130                    .map(|indicator| (newest_selection_head.row(), indicator));
1131            }
1132
1133            hover = view.hover_popover().and_then(|hover| {
1134                let (point, rendered) = hover.render(style.clone(), cx);
1135                if point.row() >= snapshot.scroll_position().y() as u32 {
1136                    if line_layouts.len() > (point.row() - start_row) as usize {
1137                        return Some((point, rendered));
1138                    }
1139                }
1140
1141                None
1142            });
1143        });
1144
1145        if let Some((_, context_menu)) = context_menu.as_mut() {
1146            context_menu.layout(
1147                SizeConstraint {
1148                    min: Vector2F::zero(),
1149                    max: vec2f(
1150                        f32::INFINITY,
1151                        (12. * line_height).min((size.y() - line_height) / 2.),
1152                    ),
1153                },
1154                cx,
1155            );
1156        }
1157
1158        if let Some((_, indicator)) = code_actions_indicator.as_mut() {
1159            indicator.layout(
1160                SizeConstraint::strict_along(Axis::Vertical, line_height * 0.618),
1161                cx,
1162            );
1163        }
1164
1165        if let Some((_, hover)) = hover.as_mut() {
1166            hover.layout(
1167                SizeConstraint {
1168                    min: Vector2F::zero(),
1169                    max: vec2f(
1170                        (120. * em_width).min(size.x()),
1171                        (size.y() - line_height) * 1. / 2.,
1172                    ),
1173                },
1174                cx,
1175            );
1176        }
1177
1178        let blocks = self.layout_blocks(
1179            start_row..end_row,
1180            &snapshot,
1181            size.x().max(scroll_width + gutter_width),
1182            gutter_padding,
1183            gutter_width,
1184            em_width,
1185            gutter_width + gutter_margin,
1186            line_height,
1187            &style,
1188            &line_layouts,
1189            cx,
1190        );
1191
1192        (
1193            size,
1194            LayoutState {
1195                size,
1196                scroll_max,
1197                gutter_size,
1198                gutter_padding,
1199                text_size,
1200                gutter_margin,
1201                snapshot,
1202                active_rows,
1203                highlighted_rows,
1204                highlighted_ranges,
1205                line_layouts,
1206                line_number_layouts,
1207                blocks,
1208                line_height,
1209                em_width,
1210                em_advance,
1211                selections,
1212                context_menu,
1213                code_actions_indicator,
1214                hover,
1215            },
1216        )
1217    }
1218
1219    fn paint(
1220        &mut self,
1221        bounds: RectF,
1222        visible_bounds: RectF,
1223        layout: &mut Self::LayoutState,
1224        cx: &mut PaintContext,
1225    ) -> Self::PaintState {
1226        cx.scene.push_layer(Some(bounds));
1227
1228        let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
1229        let text_bounds = RectF::new(
1230            bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
1231            layout.text_size,
1232        );
1233
1234        let mut paint_state = PaintState {
1235            bounds,
1236            gutter_bounds,
1237            text_bounds,
1238            hover_bounds: None,
1239        };
1240
1241        self.paint_background(gutter_bounds, text_bounds, layout, cx);
1242        if layout.gutter_size.x() > 0. {
1243            self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
1244        }
1245        self.paint_text(text_bounds, visible_bounds, layout, &mut paint_state, cx);
1246
1247        if !layout.blocks.is_empty() {
1248            cx.scene.push_layer(Some(bounds));
1249            self.paint_blocks(bounds, visible_bounds, layout, cx);
1250            cx.scene.pop_layer();
1251        }
1252
1253        cx.scene.pop_layer();
1254
1255        paint_state
1256    }
1257
1258    fn dispatch_event(
1259        &mut self,
1260        event: &Event,
1261        _: RectF,
1262        _: RectF,
1263        layout: &mut LayoutState,
1264        paint: &mut PaintState,
1265        cx: &mut EventContext,
1266    ) -> bool {
1267        if let Some((_, context_menu)) = &mut layout.context_menu {
1268            if context_menu.dispatch_event(event, cx) {
1269                return true;
1270            }
1271        }
1272
1273        if let Some((_, indicator)) = &mut layout.code_actions_indicator {
1274            if indicator.dispatch_event(event, cx) {
1275                return true;
1276            }
1277        }
1278
1279        if let Some((_, hover)) = &mut layout.hover {
1280            if hover.dispatch_event(event, cx) {
1281                return true;
1282            }
1283        }
1284
1285        for (_, block) in &mut layout.blocks {
1286            if block.dispatch_event(event, cx) {
1287                return true;
1288            }
1289        }
1290
1291        match event {
1292            Event::LeftMouseDown {
1293                position,
1294                cmd,
1295                alt,
1296                shift,
1297                click_count,
1298                ..
1299            } => self.mouse_down(
1300                *position,
1301                *cmd,
1302                *alt,
1303                *shift,
1304                *click_count,
1305                layout,
1306                paint,
1307                cx,
1308            ),
1309            Event::LeftMouseUp { position, .. } => self.mouse_up(*position, cx),
1310            Event::LeftMouseDragged { position } => {
1311                self.mouse_dragged(*position, layout, paint, cx)
1312            }
1313            Event::ScrollWheel {
1314                position,
1315                delta,
1316                precise,
1317            } => self.scroll(*position, *delta, *precise, layout, paint, cx),
1318            Event::KeyDown { input, .. } => self.key_down(input.as_deref(), cx),
1319            Event::MouseMoved { position, .. } => {
1320                if paint
1321                    .hover_bounds
1322                    .map_or(false, |hover_bounds| hover_bounds.contains_point(*position))
1323                {
1324                    return false;
1325                }
1326
1327                let point = if paint.text_bounds.contains_point(*position) {
1328                    let (point, overshoot) =
1329                        paint.point_for_position(&self.snapshot(cx), layout, *position);
1330                    if overshoot.is_zero() {
1331                        Some(point)
1332                    } else {
1333                        None
1334                    }
1335                } else {
1336                    None
1337                };
1338
1339                cx.dispatch_action(HoverAt { point });
1340                true
1341            }
1342            _ => false,
1343        }
1344    }
1345
1346    fn debug(
1347        &self,
1348        bounds: RectF,
1349        _: &Self::LayoutState,
1350        _: &Self::PaintState,
1351        _: &gpui::DebugContext,
1352    ) -> json::Value {
1353        json!({
1354            "type": "BufferElement",
1355            "bounds": bounds.to_json()
1356        })
1357    }
1358}
1359
1360pub struct LayoutState {
1361    size: Vector2F,
1362    scroll_max: Vector2F,
1363    gutter_size: Vector2F,
1364    gutter_padding: f32,
1365    gutter_margin: f32,
1366    text_size: Vector2F,
1367    snapshot: EditorSnapshot,
1368    active_rows: BTreeMap<u32, bool>,
1369    highlighted_rows: Option<Range<u32>>,
1370    line_layouts: Vec<text_layout::Line>,
1371    line_number_layouts: Vec<Option<text_layout::Line>>,
1372    blocks: Vec<(u32, ElementBox)>,
1373    line_height: f32,
1374    em_width: f32,
1375    em_advance: f32,
1376    highlighted_ranges: Vec<(Range<DisplayPoint>, Color)>,
1377    selections: Vec<(ReplicaId, Vec<SelectionLayout>)>,
1378    context_menu: Option<(DisplayPoint, ElementBox)>,
1379    code_actions_indicator: Option<(u32, ElementBox)>,
1380    hover: Option<(DisplayPoint, ElementBox)>,
1381}
1382
1383fn layout_line(
1384    row: u32,
1385    snapshot: &EditorSnapshot,
1386    style: &EditorStyle,
1387    layout_cache: &TextLayoutCache,
1388) -> text_layout::Line {
1389    let mut line = snapshot.line(row);
1390
1391    if line.len() > MAX_LINE_LEN {
1392        let mut len = MAX_LINE_LEN;
1393        while !line.is_char_boundary(len) {
1394            len -= 1;
1395        }
1396
1397        line.truncate(len);
1398    }
1399
1400    layout_cache.layout_str(
1401        &line,
1402        style.text.font_size,
1403        &[(
1404            snapshot.line_len(row) as usize,
1405            RunStyle {
1406                font_id: style.text.font_id,
1407                color: Color::black(),
1408                underline: Default::default(),
1409            },
1410        )],
1411    )
1412}
1413
1414pub struct PaintState {
1415    bounds: RectF,
1416    gutter_bounds: RectF,
1417    text_bounds: RectF,
1418    hover_bounds: Option<RectF>,
1419}
1420
1421impl PaintState {
1422    /// Returns two display points. The first is the nearest valid
1423    /// position in the current buffer and the second is the distance to the
1424    /// nearest valid position if there was overshoot.
1425    fn point_for_position(
1426        &self,
1427        snapshot: &EditorSnapshot,
1428        layout: &LayoutState,
1429        position: Vector2F,
1430    ) -> (DisplayPoint, DisplayPoint) {
1431        let scroll_position = snapshot.scroll_position();
1432        let position = position - self.text_bounds.origin();
1433        let y = position.y().max(0.0).min(layout.size.y());
1434        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
1435        let row_overshoot = row.saturating_sub(snapshot.max_point().row());
1436        let row = cmp::min(row, snapshot.max_point().row());
1437        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
1438        let x = position.x() + (scroll_position.x() * layout.em_width);
1439
1440        let column = if x >= 0.0 {
1441            line.index_for_x(x)
1442                .map(|ix| ix as u32)
1443                .unwrap_or_else(|| snapshot.line_len(row))
1444        } else {
1445            0
1446        };
1447        let column_overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
1448
1449        (
1450            DisplayPoint::new(row, column),
1451            DisplayPoint::new(row_overshoot, column_overshoot),
1452        )
1453    }
1454}
1455
1456#[derive(Copy, Clone, PartialEq, Eq)]
1457pub enum CursorShape {
1458    Bar,
1459    Block,
1460    Underscore,
1461}
1462
1463impl Default for CursorShape {
1464    fn default() -> Self {
1465        CursorShape::Bar
1466    }
1467}
1468
1469struct Cursor {
1470    origin: Vector2F,
1471    block_width: f32,
1472    line_height: f32,
1473    color: Color,
1474    shape: CursorShape,
1475    block_text: Option<Line>,
1476}
1477
1478impl Cursor {
1479    fn paint(&self, cx: &mut PaintContext) {
1480        let bounds = match self.shape {
1481            CursorShape::Bar => RectF::new(self.origin, vec2f(2.0, self.line_height)),
1482            CursorShape::Block => {
1483                RectF::new(self.origin, vec2f(self.block_width, self.line_height))
1484            }
1485            CursorShape::Underscore => RectF::new(
1486                self.origin + Vector2F::new(0.0, self.line_height - 2.0),
1487                vec2f(self.block_width, 2.0),
1488            ),
1489        };
1490
1491        cx.scene.push_quad(Quad {
1492            bounds,
1493            background: Some(self.color),
1494            border: Border::new(0., Color::black()),
1495            corner_radius: 0.,
1496        });
1497
1498        if let Some(block_text) = &self.block_text {
1499            block_text.paint(self.origin, bounds, self.line_height, cx);
1500        }
1501    }
1502}
1503
1504#[derive(Debug)]
1505struct HighlightedRange {
1506    start_y: f32,
1507    line_height: f32,
1508    lines: Vec<HighlightedRangeLine>,
1509    color: Color,
1510    corner_radius: f32,
1511}
1512
1513#[derive(Debug)]
1514struct HighlightedRangeLine {
1515    start_x: f32,
1516    end_x: f32,
1517}
1518
1519impl HighlightedRange {
1520    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1521        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1522            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1523            self.paint_lines(
1524                self.start_y + self.line_height,
1525                &self.lines[1..],
1526                bounds,
1527                scene,
1528            );
1529        } else {
1530            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1531        }
1532    }
1533
1534    fn paint_lines(
1535        &self,
1536        start_y: f32,
1537        lines: &[HighlightedRangeLine],
1538        bounds: RectF,
1539        scene: &mut Scene,
1540    ) {
1541        if lines.is_empty() {
1542            return;
1543        }
1544
1545        let mut path = PathBuilder::new();
1546        let first_line = lines.first().unwrap();
1547        let last_line = lines.last().unwrap();
1548
1549        let first_top_left = vec2f(first_line.start_x, start_y);
1550        let first_top_right = vec2f(first_line.end_x, start_y);
1551
1552        let curve_height = vec2f(0., self.corner_radius);
1553        let curve_width = |start_x: f32, end_x: f32| {
1554            let max = (end_x - start_x) / 2.;
1555            let width = if max < self.corner_radius {
1556                max
1557            } else {
1558                self.corner_radius
1559            };
1560
1561            vec2f(width, 0.)
1562        };
1563
1564        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1565        path.reset(first_top_right - top_curve_width);
1566        path.curve_to(first_top_right + curve_height, first_top_right);
1567
1568        let mut iter = lines.iter().enumerate().peekable();
1569        while let Some((ix, line)) = iter.next() {
1570            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1571
1572            if let Some((_, next_line)) = iter.peek() {
1573                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1574
1575                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1576                    Ordering::Equal => {
1577                        path.line_to(bottom_right);
1578                    }
1579                    Ordering::Less => {
1580                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1581                        path.line_to(bottom_right - curve_height);
1582                        if self.corner_radius > 0. {
1583                            path.curve_to(bottom_right - curve_width, bottom_right);
1584                        }
1585                        path.line_to(next_top_right + curve_width);
1586                        if self.corner_radius > 0. {
1587                            path.curve_to(next_top_right + curve_height, next_top_right);
1588                        }
1589                    }
1590                    Ordering::Greater => {
1591                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1592                        path.line_to(bottom_right - curve_height);
1593                        if self.corner_radius > 0. {
1594                            path.curve_to(bottom_right + curve_width, bottom_right);
1595                        }
1596                        path.line_to(next_top_right - curve_width);
1597                        if self.corner_radius > 0. {
1598                            path.curve_to(next_top_right + curve_height, next_top_right);
1599                        }
1600                    }
1601                }
1602            } else {
1603                let curve_width = curve_width(line.start_x, line.end_x);
1604                path.line_to(bottom_right - curve_height);
1605                if self.corner_radius > 0. {
1606                    path.curve_to(bottom_right - curve_width, bottom_right);
1607                }
1608
1609                let bottom_left = vec2f(line.start_x, bottom_right.y());
1610                path.line_to(bottom_left + curve_width);
1611                if self.corner_radius > 0. {
1612                    path.curve_to(bottom_left - curve_height, bottom_left);
1613                }
1614            }
1615        }
1616
1617        if first_line.start_x > last_line.start_x {
1618            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1619            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1620            path.line_to(second_top_left + curve_height);
1621            if self.corner_radius > 0. {
1622                path.curve_to(second_top_left + curve_width, second_top_left);
1623            }
1624            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1625            path.line_to(first_bottom_left - curve_width);
1626            if self.corner_radius > 0. {
1627                path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1628            }
1629        }
1630
1631        path.line_to(first_top_left + curve_height);
1632        if self.corner_radius > 0. {
1633            path.curve_to(first_top_left + top_curve_width, first_top_left);
1634        }
1635        path.line_to(first_top_right - top_curve_width);
1636
1637        scene.push_path(path.build(self.color, Some(bounds)));
1638    }
1639}
1640
1641fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1642    delta.powf(1.5) / 100.0
1643}
1644
1645fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1646    delta.powf(1.2) / 300.0
1647}
1648
1649#[cfg(test)]
1650mod tests {
1651    use std::sync::Arc;
1652
1653    use super::*;
1654    use crate::{
1655        display_map::{BlockDisposition, BlockProperties},
1656        Editor, MultiBuffer,
1657    };
1658    use settings::Settings;
1659    use util::test::sample_text;
1660
1661    #[gpui::test]
1662    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1663        cx.set_global(Settings::test(cx));
1664        let buffer = MultiBuffer::build_simple(&sample_text(6, 6, 'a'), cx);
1665        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1666            Editor::new(EditorMode::Full, buffer, None, None, None, cx)
1667        });
1668        let element = EditorElement::new(
1669            editor.downgrade(),
1670            editor.read(cx).style(cx),
1671            CursorShape::Bar,
1672        );
1673
1674        let layouts = editor.update(cx, |editor, cx| {
1675            let snapshot = editor.snapshot(cx);
1676            let mut presenter = cx.build_presenter(window_id, 30.);
1677            let mut layout_cx = presenter.build_layout_context(Vector2F::zero(), false, cx);
1678            element.layout_line_numbers(0..6, &Default::default(), &snapshot, &mut layout_cx)
1679        });
1680        assert_eq!(layouts.len(), 6);
1681    }
1682
1683    #[gpui::test]
1684    fn test_layout_with_placeholder_text_and_blocks(cx: &mut gpui::MutableAppContext) {
1685        cx.set_global(Settings::test(cx));
1686        let buffer = MultiBuffer::build_simple("", cx);
1687        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1688            Editor::new(EditorMode::Full, buffer, None, None, None, cx)
1689        });
1690
1691        editor.update(cx, |editor, cx| {
1692            editor.set_placeholder_text("hello", cx);
1693            editor.insert_blocks(
1694                [BlockProperties {
1695                    disposition: BlockDisposition::Above,
1696                    height: 3,
1697                    position: Anchor::min(),
1698                    render: Arc::new(|_| Empty::new().boxed()),
1699                }],
1700                cx,
1701            );
1702
1703            // Blur the editor so that it displays placeholder text.
1704            cx.blur();
1705        });
1706
1707        let mut element = EditorElement::new(
1708            editor.downgrade(),
1709            editor.read(cx).style(cx),
1710            CursorShape::Bar,
1711        );
1712
1713        let mut scene = Scene::new(1.0);
1714        let mut presenter = cx.build_presenter(window_id, 30.);
1715        let mut layout_cx = presenter.build_layout_context(Vector2F::zero(), false, cx);
1716        let (size, mut state) = element.layout(
1717            SizeConstraint::new(vec2f(500., 500.), vec2f(500., 500.)),
1718            &mut layout_cx,
1719        );
1720
1721        assert_eq!(state.line_layouts.len(), 4);
1722        assert_eq!(
1723            state
1724                .line_number_layouts
1725                .iter()
1726                .map(Option::is_some)
1727                .collect::<Vec<_>>(),
1728            &[false, false, false, true]
1729        );
1730
1731        // Don't panic.
1732        let bounds = RectF::new(Default::default(), size);
1733        let mut paint_cx = presenter.build_paint_context(&mut scene, bounds.size(), cx);
1734        element.paint(bounds, bounds, &mut state, &mut paint_cx);
1735    }
1736}