element.rs

   1use super::{
   2    display_map::{BlockContext, ToDisplayPoint},
   3    Anchor, DisplayPoint, Editor, EditorMode, EditorSettings, EditorSnapshot, EditorStyle, Input,
   4    Scroll, Select, SelectPhase, SoftWrap, ToPoint, MAX_LINE_LEN,
   5};
   6use clock::ReplicaId;
   7use collections::{BTreeMap, HashMap};
   8use gpui::{
   9    color::Color,
  10    elements::layout_highlighted_chunks,
  11    fonts::{HighlightStyle, Underline},
  12    geometry::{
  13        rect::RectF,
  14        vector::{vec2f, Vector2F},
  15        PathBuilder,
  16    },
  17    json::{self, ToJson},
  18    keymap::Keystroke,
  19    text_layout::{self, RunStyle, TextLayoutCache},
  20    AppContext, Axis, Border, Element, ElementBox, Event, EventContext, LayoutContext,
  21    MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext, WeakViewHandle,
  22};
  23use json::json;
  24use language::Bias;
  25use smallvec::SmallVec;
  26use std::{
  27    cmp::{self, Ordering},
  28    fmt::Write,
  29    ops::Range,
  30};
  31
  32pub struct EditorElement {
  33    view: WeakViewHandle<Editor>,
  34    settings: EditorSettings,
  35}
  36
  37impl EditorElement {
  38    pub fn new(view: WeakViewHandle<Editor>, settings: EditorSettings) -> Self {
  39        Self { view, settings }
  40    }
  41
  42    fn view<'a>(&self, cx: &'a AppContext) -> &'a Editor {
  43        self.view.upgrade(cx).unwrap().read(cx)
  44    }
  45
  46    fn update_view<F, T>(&self, cx: &mut MutableAppContext, f: F) -> T
  47    where
  48        F: FnOnce(&mut Editor, &mut ViewContext<Editor>) -> T,
  49    {
  50        self.view.upgrade(cx).unwrap().update(cx, f)
  51    }
  52
  53    fn snapshot(&self, cx: &mut MutableAppContext) -> EditorSnapshot {
  54        self.update_view(cx, |view, cx| view.snapshot(cx))
  55    }
  56
  57    fn mouse_down(
  58        &self,
  59        position: Vector2F,
  60        alt: bool,
  61        shift: bool,
  62        mut click_count: usize,
  63        layout: &mut LayoutState,
  64        paint: &mut PaintState,
  65        cx: &mut EventContext,
  66    ) -> bool {
  67        if paint.gutter_bounds.contains_point(position) {
  68            click_count = 3; // Simulate triple-click when clicking the gutter to select lines
  69        } else if !paint.text_bounds.contains_point(position) {
  70            return false;
  71        }
  72
  73        let snapshot = self.snapshot(cx.app);
  74        let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
  75
  76        if shift && alt {
  77            cx.dispatch_action(Select(SelectPhase::BeginColumnar {
  78                position,
  79                overshoot,
  80            }));
  81        } else if shift {
  82            cx.dispatch_action(Select(SelectPhase::Extend {
  83                position,
  84                click_count,
  85            }));
  86        } else {
  87            cx.dispatch_action(Select(SelectPhase::Begin {
  88                position,
  89                add: alt,
  90                click_count,
  91            }));
  92        }
  93
  94        true
  95    }
  96
  97    fn mouse_up(&self, _position: Vector2F, cx: &mut EventContext) -> bool {
  98        if self.view(cx.app.as_ref()).is_selecting() {
  99            cx.dispatch_action(Select(SelectPhase::End));
 100            true
 101        } else {
 102            false
 103        }
 104    }
 105
 106    fn mouse_dragged(
 107        &self,
 108        position: Vector2F,
 109        layout: &mut LayoutState,
 110        paint: &mut PaintState,
 111        cx: &mut EventContext,
 112    ) -> bool {
 113        let view = self.view(cx.app.as_ref());
 114
 115        if view.is_selecting() {
 116            let rect = paint.text_bounds;
 117            let mut scroll_delta = Vector2F::zero();
 118
 119            let vertical_margin = layout.line_height.min(rect.height() / 3.0);
 120            let top = rect.origin_y() + vertical_margin;
 121            let bottom = rect.lower_left().y() - vertical_margin;
 122            if position.y() < top {
 123                scroll_delta.set_y(-scale_vertical_mouse_autoscroll_delta(top - position.y()))
 124            }
 125            if position.y() > bottom {
 126                scroll_delta.set_y(scale_vertical_mouse_autoscroll_delta(position.y() - bottom))
 127            }
 128
 129            let horizontal_margin = layout.line_height.min(rect.width() / 3.0);
 130            let left = rect.origin_x() + horizontal_margin;
 131            let right = rect.upper_right().x() - horizontal_margin;
 132            if position.x() < left {
 133                scroll_delta.set_x(-scale_horizontal_mouse_autoscroll_delta(
 134                    left - position.x(),
 135                ))
 136            }
 137            if position.x() > right {
 138                scroll_delta.set_x(scale_horizontal_mouse_autoscroll_delta(
 139                    position.x() - right,
 140                ))
 141            }
 142
 143            let snapshot = self.snapshot(cx.app);
 144            let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
 145
 146            cx.dispatch_action(Select(SelectPhase::Update {
 147                position,
 148                overshoot,
 149                scroll_position: (snapshot.scroll_position() + scroll_delta)
 150                    .clamp(Vector2F::zero(), layout.scroll_max),
 151            }));
 152            true
 153        } else {
 154            false
 155        }
 156    }
 157
 158    fn key_down(&self, chars: &str, keystroke: &Keystroke, cx: &mut EventContext) -> bool {
 159        let view = self.view.upgrade(cx.app).unwrap();
 160
 161        if view.is_focused(cx.app) {
 162            if chars.is_empty() {
 163                false
 164            } else {
 165                if chars.chars().any(|c| c.is_control()) || keystroke.cmd || keystroke.ctrl {
 166                    false
 167                } else {
 168                    cx.dispatch_action(Input(chars.to_string()));
 169                    true
 170                }
 171            }
 172        } else {
 173            false
 174        }
 175    }
 176
 177    fn scroll(
 178        &self,
 179        position: Vector2F,
 180        mut delta: Vector2F,
 181        precise: bool,
 182        layout: &mut LayoutState,
 183        paint: &mut PaintState,
 184        cx: &mut EventContext,
 185    ) -> bool {
 186        if !paint.bounds.contains_point(position) {
 187            return false;
 188        }
 189
 190        let snapshot = self.snapshot(cx.app);
 191        let max_glyph_width = layout.em_width;
 192        if !precise {
 193            delta *= vec2f(max_glyph_width, layout.line_height);
 194        }
 195
 196        let scroll_position = snapshot.scroll_position();
 197        let x = (scroll_position.x() * max_glyph_width - delta.x()) / max_glyph_width;
 198        let y = (scroll_position.y() * layout.line_height - delta.y()) / layout.line_height;
 199        let scroll_position = vec2f(x, y).clamp(Vector2F::zero(), layout.scroll_max);
 200
 201        cx.dispatch_action(Scroll(scroll_position));
 202
 203        true
 204    }
 205
 206    fn paint_background(
 207        &self,
 208        gutter_bounds: RectF,
 209        text_bounds: RectF,
 210        layout: &LayoutState,
 211        cx: &mut PaintContext,
 212    ) {
 213        let bounds = gutter_bounds.union_rect(text_bounds);
 214        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 215        let editor = self.view(cx.app);
 216        let style = &self.settings.style;
 217        cx.scene.push_quad(Quad {
 218            bounds: gutter_bounds,
 219            background: Some(style.gutter_background),
 220            border: Border::new(0., Color::transparent_black()),
 221            corner_radius: 0.,
 222        });
 223        cx.scene.push_quad(Quad {
 224            bounds: text_bounds,
 225            background: Some(style.background),
 226            border: Border::new(0., Color::transparent_black()),
 227            corner_radius: 0.,
 228        });
 229
 230        if let EditorMode::Full = editor.mode {
 231            let mut active_rows = layout.active_rows.iter().peekable();
 232            while let Some((start_row, contains_non_empty_selection)) = active_rows.next() {
 233                let mut end_row = *start_row;
 234                while active_rows.peek().map_or(false, |r| {
 235                    *r.0 == end_row + 1 && r.1 == contains_non_empty_selection
 236                }) {
 237                    active_rows.next().unwrap();
 238                    end_row += 1;
 239                }
 240
 241                if !contains_non_empty_selection {
 242                    let origin = vec2f(
 243                        bounds.origin_x(),
 244                        bounds.origin_y() + (layout.line_height * *start_row as f32) - scroll_top,
 245                    );
 246                    let size = vec2f(
 247                        bounds.width(),
 248                        layout.line_height * (end_row - start_row + 1) as f32,
 249                    );
 250                    cx.scene.push_quad(Quad {
 251                        bounds: RectF::new(origin, size),
 252                        background: Some(style.active_line_background),
 253                        border: Border::default(),
 254                        corner_radius: 0.,
 255                    });
 256                }
 257            }
 258
 259            if let Some(highlighted_rows) = &layout.highlighted_rows {
 260                let origin = vec2f(
 261                    bounds.origin_x(),
 262                    bounds.origin_y() + (layout.line_height * highlighted_rows.start as f32)
 263                        - scroll_top,
 264                );
 265                let size = vec2f(
 266                    bounds.width(),
 267                    layout.line_height * highlighted_rows.len() as f32,
 268                );
 269                cx.scene.push_quad(Quad {
 270                    bounds: RectF::new(origin, size),
 271                    background: Some(style.highlighted_line_background),
 272                    border: Border::default(),
 273                    corner_radius: 0.,
 274                });
 275            }
 276        }
 277    }
 278
 279    fn paint_gutter(
 280        &mut self,
 281        bounds: RectF,
 282        visible_bounds: RectF,
 283        layout: &LayoutState,
 284        cx: &mut PaintContext,
 285    ) {
 286        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 287        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
 288            if let Some(line) = line {
 289                let line_origin = bounds.origin()
 290                    + vec2f(
 291                        bounds.width() - line.width() - layout.gutter_padding,
 292                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
 293                    );
 294                line.paint(line_origin, visible_bounds, layout.line_height, cx);
 295            }
 296        }
 297    }
 298
 299    fn paint_text(
 300        &mut self,
 301        bounds: RectF,
 302        visible_bounds: RectF,
 303        layout: &mut LayoutState,
 304        cx: &mut PaintContext,
 305    ) {
 306        let view = self.view(cx.app);
 307        let style = &self.settings.style;
 308        let local_replica_id = view.replica_id(cx);
 309        let scroll_position = layout.snapshot.scroll_position();
 310        let start_row = scroll_position.y() as u32;
 311        let scroll_top = scroll_position.y() * layout.line_height;
 312        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 313        let max_glyph_width = layout.em_width;
 314        let scroll_left = scroll_position.x() * max_glyph_width;
 315        let content_origin = bounds.origin() + layout.text_offset;
 316
 317        cx.scene.push_layer(Some(bounds));
 318
 319        for (range, color) in &layout.highlighted_ranges {
 320            self.paint_highlighted_range(
 321                range.clone(),
 322                start_row,
 323                end_row,
 324                *color,
 325                0.,
 326                0.15 * layout.line_height,
 327                layout,
 328                content_origin,
 329                scroll_top,
 330                scroll_left,
 331                bounds,
 332                cx,
 333            );
 334        }
 335
 336        let mut cursors = SmallVec::<[Cursor; 32]>::new();
 337        for (replica_id, selections) in &layout.selections {
 338            let style = style.replica_selection_style(*replica_id);
 339            let corner_radius = 0.15 * layout.line_height;
 340
 341            for selection in selections {
 342                self.paint_highlighted_range(
 343                    selection.start..selection.end,
 344                    start_row,
 345                    end_row,
 346                    style.selection,
 347                    corner_radius,
 348                    corner_radius * 2.,
 349                    layout,
 350                    content_origin,
 351                    scroll_top,
 352                    scroll_left,
 353                    bounds,
 354                    cx,
 355                );
 356
 357                if view.show_local_cursors() || *replica_id != local_replica_id {
 358                    let cursor_position = selection.head();
 359                    if (start_row..end_row).contains(&cursor_position.row()) {
 360                        let cursor_row_layout =
 361                            &layout.line_layouts[(cursor_position.row() - start_row) as usize];
 362                        let x = cursor_row_layout.x_for_index(cursor_position.column() as usize)
 363                            - scroll_left;
 364                        let y = cursor_position.row() as f32 * layout.line_height - scroll_top;
 365                        cursors.push(Cursor {
 366                            color: style.cursor,
 367                            origin: content_origin + vec2f(x, y),
 368                            line_height: layout.line_height,
 369                        });
 370                    }
 371                }
 372            }
 373        }
 374
 375        if let Some(visible_text_bounds) = bounds.intersection(visible_bounds) {
 376            // Draw glyphs
 377            for (ix, line) in layout.line_layouts.iter().enumerate() {
 378                let row = start_row + ix as u32;
 379                line.paint(
 380                    content_origin
 381                        + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
 382                    visible_text_bounds,
 383                    layout.line_height,
 384                    cx,
 385                );
 386            }
 387        }
 388
 389        cx.scene.push_layer(Some(bounds));
 390        for cursor in cursors {
 391            cursor.paint(cx);
 392        }
 393        cx.scene.pop_layer();
 394
 395        if let Some((position, completions_list)) = layout.completions.as_mut() {
 396            cx.scene.push_stacking_context(None);
 397
 398            let cursor_row_layout = &layout.line_layouts[(position.row() - start_row) as usize];
 399            let x = cursor_row_layout.x_for_index(position.column() as usize) - scroll_left;
 400            let y = (position.row() + 1) as f32 * layout.line_height - scroll_top;
 401            let mut list_origin = content_origin + vec2f(x, y);
 402            let list_height = completions_list.size().y();
 403
 404            if list_origin.y() + list_height > bounds.lower_left().y() {
 405                list_origin.set_y(list_origin.y() - layout.line_height - list_height);
 406            }
 407
 408            completions_list.paint(
 409                list_origin,
 410                RectF::from_points(Vector2F::zero(), vec2f(f32::MAX, f32::MAX)), // Let content bleed outside of editor
 411                cx,
 412            );
 413
 414            cx.scene.pop_stacking_context();
 415        }
 416
 417        cx.scene.pop_layer();
 418    }
 419
 420    fn paint_highlighted_range(
 421        &self,
 422        range: Range<DisplayPoint>,
 423        start_row: u32,
 424        end_row: u32,
 425        color: Color,
 426        corner_radius: f32,
 427        line_end_overshoot: f32,
 428        layout: &LayoutState,
 429        content_origin: Vector2F,
 430        scroll_top: f32,
 431        scroll_left: f32,
 432        bounds: RectF,
 433        cx: &mut PaintContext,
 434    ) {
 435        if range.start != range.end {
 436            let row_range = if range.end.column() == 0 {
 437                cmp::max(range.start.row(), start_row)..cmp::min(range.end.row(), end_row)
 438            } else {
 439                cmp::max(range.start.row(), start_row)..cmp::min(range.end.row() + 1, end_row)
 440            };
 441
 442            let highlighted_range = HighlightedRange {
 443                color,
 444                line_height: layout.line_height,
 445                corner_radius,
 446                start_y: content_origin.y() + row_range.start as f32 * layout.line_height
 447                    - scroll_top,
 448                lines: row_range
 449                    .into_iter()
 450                    .map(|row| {
 451                        let line_layout = &layout.line_layouts[(row - start_row) as usize];
 452                        HighlightedRangeLine {
 453                            start_x: if row == range.start.row() {
 454                                content_origin.x()
 455                                    + line_layout.x_for_index(range.start.column() as usize)
 456                                    - scroll_left
 457                            } else {
 458                                content_origin.x() - scroll_left
 459                            },
 460                            end_x: if row == range.end.row() {
 461                                content_origin.x()
 462                                    + line_layout.x_for_index(range.end.column() as usize)
 463                                    - scroll_left
 464                            } else {
 465                                content_origin.x() + line_layout.width() + line_end_overshoot
 466                                    - scroll_left
 467                            },
 468                        }
 469                    })
 470                    .collect(),
 471            };
 472
 473            highlighted_range.paint(bounds, cx.scene);
 474        }
 475    }
 476
 477    fn paint_blocks(
 478        &mut self,
 479        bounds: RectF,
 480        visible_bounds: RectF,
 481        layout: &mut LayoutState,
 482        cx: &mut PaintContext,
 483    ) {
 484        let scroll_position = layout.snapshot.scroll_position();
 485        let scroll_left = scroll_position.x() * layout.em_width;
 486        let scroll_top = scroll_position.y() * layout.line_height;
 487
 488        for (row, element) in &mut layout.blocks {
 489            let origin = bounds.origin()
 490                + vec2f(-scroll_left, *row as f32 * layout.line_height - scroll_top);
 491            element.paint(origin, visible_bounds, cx);
 492        }
 493    }
 494
 495    fn max_line_number_width(&self, snapshot: &EditorSnapshot, cx: &LayoutContext) -> f32 {
 496        let digit_count = (snapshot.max_buffer_row() as f32).log10().floor() as usize + 1;
 497        let style = &self.settings.style;
 498
 499        cx.text_layout_cache
 500            .layout_str(
 501                "1".repeat(digit_count).as_str(),
 502                style.text.font_size,
 503                &[(
 504                    digit_count,
 505                    RunStyle {
 506                        font_id: style.text.font_id,
 507                        color: Color::black(),
 508                        underline: None,
 509                    },
 510                )],
 511            )
 512            .width()
 513    }
 514
 515    fn layout_line_numbers(
 516        &self,
 517        rows: Range<u32>,
 518        active_rows: &BTreeMap<u32, bool>,
 519        snapshot: &EditorSnapshot,
 520        cx: &LayoutContext,
 521    ) -> Vec<Option<text_layout::Line>> {
 522        let style = &self.settings.style;
 523        let include_line_numbers = snapshot.mode == EditorMode::Full;
 524        let mut line_number_layouts = Vec::with_capacity(rows.len());
 525        let mut line_number = String::new();
 526        for (ix, row) in snapshot
 527            .buffer_rows(rows.start)
 528            .take((rows.end - rows.start) as usize)
 529            .enumerate()
 530        {
 531            let display_row = rows.start + ix as u32;
 532            let color = if active_rows.contains_key(&display_row) {
 533                style.line_number_active
 534            } else {
 535                style.line_number
 536            };
 537            if let Some(buffer_row) = row {
 538                if include_line_numbers {
 539                    line_number.clear();
 540                    write!(&mut line_number, "{}", buffer_row + 1).unwrap();
 541                    line_number_layouts.push(Some(cx.text_layout_cache.layout_str(
 542                        &line_number,
 543                        style.text.font_size,
 544                        &[(
 545                            line_number.len(),
 546                            RunStyle {
 547                                font_id: style.text.font_id,
 548                                color,
 549                                underline: None,
 550                            },
 551                        )],
 552                    )));
 553                }
 554            } else {
 555                line_number_layouts.push(None);
 556            }
 557        }
 558
 559        line_number_layouts
 560    }
 561
 562    fn layout_lines(
 563        &mut self,
 564        mut rows: Range<u32>,
 565        snapshot: &mut EditorSnapshot,
 566        cx: &LayoutContext,
 567    ) -> Vec<text_layout::Line> {
 568        rows.end = cmp::min(rows.end, snapshot.max_point().row() + 1);
 569        if rows.start >= rows.end {
 570            return Vec::new();
 571        }
 572
 573        // When the editor is empty and unfocused, then show the placeholder.
 574        if snapshot.is_empty() && !snapshot.is_focused() {
 575            let placeholder_style = self.settings.style.placeholder_text();
 576            let placeholder_text = snapshot.placeholder_text();
 577            let placeholder_lines = placeholder_text
 578                .as_ref()
 579                .map_or("", AsRef::as_ref)
 580                .split('\n')
 581                .skip(rows.start as usize)
 582                .take(rows.len());
 583            return placeholder_lines
 584                .map(|line| {
 585                    cx.text_layout_cache.layout_str(
 586                        line,
 587                        placeholder_style.font_size,
 588                        &[(
 589                            line.len(),
 590                            RunStyle {
 591                                font_id: placeholder_style.font_id,
 592                                color: placeholder_style.color,
 593                                underline: None,
 594                            },
 595                        )],
 596                    )
 597                })
 598                .collect();
 599        } else {
 600            let style = &self.settings.style;
 601            let chunks = snapshot
 602                .chunks(rows.clone(), Some(&style.syntax))
 603                .map(|chunk| {
 604                    let highlight = if let Some(severity) = chunk.diagnostic {
 605                        let diagnostic_style = super::diagnostic_style(severity, true, style);
 606                        let underline = Some(Underline {
 607                            color: diagnostic_style.message.text.color,
 608                            thickness: 1.0.into(),
 609                            squiggly: true,
 610                        });
 611                        if let Some(mut highlight) = chunk.highlight_style {
 612                            highlight.underline = underline;
 613                            Some(highlight)
 614                        } else {
 615                            Some(HighlightStyle {
 616                                underline,
 617                                color: style.text.color,
 618                                font_properties: style.text.font_properties,
 619                            })
 620                        }
 621                    } else {
 622                        chunk.highlight_style
 623                    };
 624                    (chunk.text, highlight)
 625                });
 626            layout_highlighted_chunks(
 627                chunks,
 628                &style.text,
 629                &cx.text_layout_cache,
 630                &cx.font_cache,
 631                MAX_LINE_LEN,
 632                rows.len() as usize,
 633            )
 634        }
 635    }
 636
 637    fn layout_blocks(
 638        &mut self,
 639        rows: Range<u32>,
 640        snapshot: &EditorSnapshot,
 641        width: f32,
 642        gutter_padding: f32,
 643        gutter_width: f32,
 644        em_width: f32,
 645        text_x: f32,
 646        line_height: f32,
 647        style: &EditorStyle,
 648        line_layouts: &[text_layout::Line],
 649        cx: &mut LayoutContext,
 650    ) -> Vec<(u32, ElementBox)> {
 651        snapshot
 652            .blocks_in_range(rows.clone())
 653            .map(|(start_row, block)| {
 654                let anchor_row = block
 655                    .position()
 656                    .to_point(&snapshot.buffer_snapshot)
 657                    .to_display_point(snapshot)
 658                    .row();
 659
 660                let anchor_x = text_x
 661                    + if rows.contains(&anchor_row) {
 662                        line_layouts[(anchor_row - rows.start) as usize]
 663                            .x_for_index(block.column() as usize)
 664                    } else {
 665                        layout_line(anchor_row, snapshot, style, cx.text_layout_cache)
 666                            .x_for_index(block.column() as usize)
 667                    };
 668
 669                let mut element = block.render(&BlockContext {
 670                    cx,
 671                    anchor_x,
 672                    gutter_padding,
 673                    line_height,
 674                    scroll_x: snapshot.scroll_position.x(),
 675                    gutter_width,
 676                    em_width,
 677                });
 678                element.layout(
 679                    SizeConstraint {
 680                        min: Vector2F::zero(),
 681                        max: vec2f(width, block.height() as f32 * line_height),
 682                    },
 683                    cx,
 684                );
 685                (start_row, element)
 686            })
 687            .collect()
 688    }
 689}
 690
 691impl Element for EditorElement {
 692    type LayoutState = LayoutState;
 693    type PaintState = PaintState;
 694
 695    fn layout(
 696        &mut self,
 697        constraint: SizeConstraint,
 698        cx: &mut LayoutContext,
 699    ) -> (Vector2F, Self::LayoutState) {
 700        let mut size = constraint.max;
 701        if size.x().is_infinite() {
 702            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 703        }
 704
 705        let snapshot = self.snapshot(cx.app);
 706        let style = self.settings.style.clone();
 707        let line_height = style.text.line_height(cx.font_cache);
 708
 709        let gutter_padding;
 710        let gutter_width;
 711        if snapshot.mode == EditorMode::Full {
 712            gutter_padding = style.text.em_width(cx.font_cache) * style.gutter_padding_factor;
 713            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 714        } else {
 715            gutter_padding = 0.0;
 716            gutter_width = 0.0
 717        };
 718
 719        let text_width = size.x() - gutter_width;
 720        let text_offset = vec2f(-style.text.descent(cx.font_cache), 0.);
 721        let em_width = style.text.em_width(cx.font_cache);
 722        let em_advance = style.text.em_advance(cx.font_cache);
 723        let overscroll = vec2f(em_width, 0.);
 724        let wrap_width = match self.settings.soft_wrap {
 725            SoftWrap::None => None,
 726            SoftWrap::EditorWidth => Some(text_width - text_offset.x() - overscroll.x() - em_width),
 727            SoftWrap::Column(column) => Some(column as f32 * em_advance),
 728        };
 729        let snapshot = self.update_view(cx.app, |view, cx| {
 730            if view.set_wrap_width(wrap_width, cx) {
 731                view.snapshot(cx)
 732            } else {
 733                snapshot
 734            }
 735        });
 736
 737        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
 738        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
 739            size.set_y(
 740                scroll_height
 741                    .min(constraint.max_along(Axis::Vertical))
 742                    .max(constraint.min_along(Axis::Vertical))
 743                    .min(line_height * max_lines as f32),
 744            )
 745        } else if size.y().is_infinite() {
 746            size.set_y(scroll_height);
 747        }
 748        let gutter_size = vec2f(gutter_width, size.y());
 749        let text_size = vec2f(text_width, size.y());
 750
 751        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
 752            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
 753            let snapshot = view.snapshot(cx);
 754            (autoscroll_horizontally, snapshot)
 755        });
 756
 757        let scroll_position = snapshot.scroll_position();
 758        let start_row = scroll_position.y() as u32;
 759        let scroll_top = scroll_position.y() * line_height;
 760        let end_row = ((scroll_top + size.y()) / line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 761
 762        let start_anchor = if start_row == 0 {
 763            Anchor::min()
 764        } else {
 765            snapshot
 766                .buffer_snapshot
 767                .anchor_before(DisplayPoint::new(start_row, 0).to_offset(&snapshot, Bias::Left))
 768        };
 769        let end_anchor = if end_row > snapshot.max_point().row() {
 770            Anchor::max()
 771        } else {
 772            snapshot
 773                .buffer_snapshot
 774                .anchor_before(DisplayPoint::new(end_row, 0).to_offset(&snapshot, Bias::Right))
 775        };
 776
 777        let mut selections = HashMap::default();
 778        let mut active_rows = BTreeMap::new();
 779        let mut highlighted_rows = None;
 780        let mut highlighted_ranges = Vec::new();
 781        self.update_view(cx.app, |view, cx| {
 782            let display_map = view.display_map.update(cx, |map, cx| map.snapshot(cx));
 783
 784            highlighted_rows = view.highlighted_rows();
 785            highlighted_ranges = view.highlighted_ranges_in_range(
 786                start_anchor.clone()..end_anchor.clone(),
 787                &display_map,
 788            );
 789
 790            let local_selections = view
 791                .local_selections_in_range(start_anchor.clone()..end_anchor.clone(), &display_map);
 792            for selection in &local_selections {
 793                let is_empty = selection.start == selection.end;
 794                let selection_start = snapshot.prev_line_boundary(selection.start).1;
 795                let selection_end = snapshot.next_line_boundary(selection.end).1;
 796                for row in cmp::max(selection_start.row(), start_row)
 797                    ..=cmp::min(selection_end.row(), end_row)
 798                {
 799                    let contains_non_empty_selection = active_rows.entry(row).or_insert(!is_empty);
 800                    *contains_non_empty_selection |= !is_empty;
 801                }
 802            }
 803            selections.insert(
 804                view.replica_id(cx),
 805                local_selections
 806                    .into_iter()
 807                    .map(|selection| crate::Selection {
 808                        id: selection.id,
 809                        goal: selection.goal,
 810                        reversed: selection.reversed,
 811                        start: selection.start.to_display_point(&display_map),
 812                        end: selection.end.to_display_point(&display_map),
 813                    })
 814                    .collect(),
 815            );
 816
 817            for (replica_id, selection) in display_map
 818                .buffer_snapshot
 819                .remote_selections_in_range(&(start_anchor..end_anchor))
 820            {
 821                selections
 822                    .entry(replica_id)
 823                    .or_insert(Vec::new())
 824                    .push(crate::Selection {
 825                        id: selection.id,
 826                        goal: selection.goal,
 827                        reversed: selection.reversed,
 828                        start: selection.start.to_display_point(&display_map),
 829                        end: selection.end.to_display_point(&display_map),
 830                    });
 831            }
 832        });
 833
 834        let line_number_layouts =
 835            self.layout_line_numbers(start_row..end_row, &active_rows, &snapshot, cx);
 836
 837        let mut max_visible_line_width = 0.0;
 838        let line_layouts = self.layout_lines(start_row..end_row, &mut snapshot, cx);
 839        for line in &line_layouts {
 840            if line.width() > max_visible_line_width {
 841                max_visible_line_width = line.width();
 842            }
 843        }
 844
 845        let style = self.settings.style.clone();
 846        let longest_line_width = layout_line(
 847            snapshot.longest_row(),
 848            &snapshot,
 849            &style,
 850            cx.text_layout_cache,
 851        )
 852        .width();
 853        let scroll_width = longest_line_width.max(max_visible_line_width) + overscroll.x();
 854        let em_width = style.text.em_width(cx.font_cache);
 855        let max_row = snapshot.max_point().row();
 856        let scroll_max = vec2f(
 857            ((scroll_width - text_size.x()) / em_width).max(0.0),
 858            max_row.saturating_sub(1) as f32,
 859        );
 860
 861        let mut completions = None;
 862        self.update_view(cx.app, |view, cx| {
 863            let clamped = view.clamp_scroll_left(scroll_max.x());
 864            let autoscrolled;
 865            if autoscroll_horizontally {
 866                autoscrolled = view.autoscroll_horizontally(
 867                    start_row,
 868                    text_size.x(),
 869                    scroll_width,
 870                    em_width,
 871                    &line_layouts,
 872                    cx,
 873                );
 874            } else {
 875                autoscrolled = false;
 876            }
 877
 878            if clamped || autoscrolled {
 879                snapshot = view.snapshot(cx);
 880            }
 881
 882            if view.has_completions() {
 883                let newest_selection_head = view
 884                    .newest_selection::<usize>(&snapshot.buffer_snapshot)
 885                    .head()
 886                    .to_display_point(&snapshot);
 887
 888                if (start_row..end_row).contains(&newest_selection_head.row()) {
 889                    let list = view.render_completions(cx).unwrap();
 890                    completions = Some((newest_selection_head, list));
 891                }
 892            }
 893        });
 894
 895        if let Some((_, completions_list)) = completions.as_mut() {
 896            completions_list.layout(
 897                SizeConstraint {
 898                    min: Vector2F::zero(),
 899                    max: vec2f(800., (12. * line_height).min((size.y() - line_height) / 2.)),
 900                },
 901                cx,
 902            );
 903        }
 904
 905        let blocks = self.layout_blocks(
 906            start_row..end_row,
 907            &snapshot,
 908            size.x().max(scroll_width + gutter_width),
 909            gutter_padding,
 910            gutter_width,
 911            em_width,
 912            gutter_width + text_offset.x(),
 913            line_height,
 914            &style,
 915            &line_layouts,
 916            cx,
 917        );
 918
 919        (
 920            size,
 921            LayoutState {
 922                size,
 923                scroll_max,
 924                gutter_size,
 925                gutter_padding,
 926                text_size,
 927                text_offset,
 928                snapshot,
 929                active_rows,
 930                highlighted_rows,
 931                highlighted_ranges,
 932                line_layouts,
 933                line_number_layouts,
 934                blocks,
 935                line_height,
 936                em_width,
 937                em_advance,
 938                selections,
 939                completions,
 940            },
 941        )
 942    }
 943
 944    fn paint(
 945        &mut self,
 946        bounds: RectF,
 947        visible_bounds: RectF,
 948        layout: &mut Self::LayoutState,
 949        cx: &mut PaintContext,
 950    ) -> Self::PaintState {
 951        cx.scene.push_layer(Some(bounds));
 952
 953        let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
 954        let text_bounds = RectF::new(
 955            bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
 956            layout.text_size,
 957        );
 958
 959        self.paint_background(gutter_bounds, text_bounds, layout, cx);
 960        if layout.gutter_size.x() > 0. {
 961            self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
 962        }
 963        self.paint_text(text_bounds, visible_bounds, layout, cx);
 964
 965        if !layout.blocks.is_empty() {
 966            cx.scene.push_layer(Some(bounds));
 967            self.paint_blocks(bounds, visible_bounds, layout, cx);
 968            cx.scene.pop_layer();
 969        }
 970
 971        cx.scene.pop_layer();
 972
 973        PaintState {
 974            bounds,
 975            gutter_bounds,
 976            text_bounds,
 977        }
 978    }
 979
 980    fn dispatch_event(
 981        &mut self,
 982        event: &Event,
 983        _: RectF,
 984        layout: &mut LayoutState,
 985        paint: &mut PaintState,
 986        cx: &mut EventContext,
 987    ) -> bool {
 988        if let Some((_, completion_list)) = &mut layout.completions {
 989            if completion_list.dispatch_event(event, cx) {
 990                return true;
 991            }
 992        }
 993
 994        match event {
 995            Event::LeftMouseDown {
 996                position,
 997                alt,
 998                shift,
 999                click_count,
1000                ..
1001            } => self.mouse_down(*position, *alt, *shift, *click_count, layout, paint, cx),
1002            Event::LeftMouseUp { position } => self.mouse_up(*position, cx),
1003            Event::LeftMouseDragged { position } => {
1004                self.mouse_dragged(*position, layout, paint, cx)
1005            }
1006            Event::ScrollWheel {
1007                position,
1008                delta,
1009                precise,
1010            } => self.scroll(*position, *delta, *precise, layout, paint, cx),
1011            Event::KeyDown {
1012                chars, keystroke, ..
1013            } => self.key_down(chars, keystroke, cx),
1014            _ => false,
1015        }
1016    }
1017
1018    fn debug(
1019        &self,
1020        bounds: RectF,
1021        _: &Self::LayoutState,
1022        _: &Self::PaintState,
1023        _: &gpui::DebugContext,
1024    ) -> json::Value {
1025        json!({
1026            "type": "BufferElement",
1027            "bounds": bounds.to_json()
1028        })
1029    }
1030}
1031
1032pub struct LayoutState {
1033    size: Vector2F,
1034    scroll_max: Vector2F,
1035    gutter_size: Vector2F,
1036    gutter_padding: f32,
1037    text_size: Vector2F,
1038    snapshot: EditorSnapshot,
1039    active_rows: BTreeMap<u32, bool>,
1040    highlighted_rows: Option<Range<u32>>,
1041    line_layouts: Vec<text_layout::Line>,
1042    line_number_layouts: Vec<Option<text_layout::Line>>,
1043    blocks: Vec<(u32, ElementBox)>,
1044    line_height: f32,
1045    em_width: f32,
1046    em_advance: f32,
1047    highlighted_ranges: Vec<(Range<DisplayPoint>, Color)>,
1048    selections: HashMap<ReplicaId, Vec<text::Selection<DisplayPoint>>>,
1049    text_offset: Vector2F,
1050    completions: Option<(DisplayPoint, ElementBox)>,
1051}
1052
1053fn layout_line(
1054    row: u32,
1055    snapshot: &EditorSnapshot,
1056    style: &EditorStyle,
1057    layout_cache: &TextLayoutCache,
1058) -> text_layout::Line {
1059    let mut line = snapshot.line(row);
1060
1061    if line.len() > MAX_LINE_LEN {
1062        let mut len = MAX_LINE_LEN;
1063        while !line.is_char_boundary(len) {
1064            len -= 1;
1065        }
1066        line.truncate(len);
1067    }
1068
1069    layout_cache.layout_str(
1070        &line,
1071        style.text.font_size,
1072        &[(
1073            snapshot.line_len(row) as usize,
1074            RunStyle {
1075                font_id: style.text.font_id,
1076                color: Color::black(),
1077                underline: None,
1078            },
1079        )],
1080    )
1081}
1082
1083pub struct PaintState {
1084    bounds: RectF,
1085    gutter_bounds: RectF,
1086    text_bounds: RectF,
1087}
1088
1089impl PaintState {
1090    fn point_for_position(
1091        &self,
1092        snapshot: &EditorSnapshot,
1093        layout: &LayoutState,
1094        position: Vector2F,
1095    ) -> (DisplayPoint, u32) {
1096        let scroll_position = snapshot.scroll_position();
1097        let position = position - self.text_bounds.origin();
1098        let y = position.y().max(0.0).min(layout.size.y());
1099        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
1100        let row = cmp::min(row, snapshot.max_point().row());
1101        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
1102        let x = position.x() + (scroll_position.x() * layout.em_width);
1103
1104        let column = if x >= 0.0 {
1105            line.index_for_x(x)
1106                .map(|ix| ix as u32)
1107                .unwrap_or_else(|| snapshot.line_len(row))
1108        } else {
1109            0
1110        };
1111        let overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
1112
1113        (DisplayPoint::new(row, column), overshoot)
1114    }
1115}
1116
1117struct Cursor {
1118    origin: Vector2F,
1119    line_height: f32,
1120    color: Color,
1121}
1122
1123impl Cursor {
1124    fn paint(&self, cx: &mut PaintContext) {
1125        cx.scene.push_quad(Quad {
1126            bounds: RectF::new(self.origin, vec2f(2.0, self.line_height)),
1127            background: Some(self.color),
1128            border: Border::new(0., Color::black()),
1129            corner_radius: 0.,
1130        });
1131    }
1132}
1133
1134#[derive(Debug)]
1135struct HighlightedRange {
1136    start_y: f32,
1137    line_height: f32,
1138    lines: Vec<HighlightedRangeLine>,
1139    color: Color,
1140    corner_radius: f32,
1141}
1142
1143#[derive(Debug)]
1144struct HighlightedRangeLine {
1145    start_x: f32,
1146    end_x: f32,
1147}
1148
1149impl HighlightedRange {
1150    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1151        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1152            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1153            self.paint_lines(
1154                self.start_y + self.line_height,
1155                &self.lines[1..],
1156                bounds,
1157                scene,
1158            );
1159        } else {
1160            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1161        }
1162    }
1163
1164    fn paint_lines(
1165        &self,
1166        start_y: f32,
1167        lines: &[HighlightedRangeLine],
1168        bounds: RectF,
1169        scene: &mut Scene,
1170    ) {
1171        if lines.is_empty() {
1172            return;
1173        }
1174
1175        let mut path = PathBuilder::new();
1176        let first_line = lines.first().unwrap();
1177        let last_line = lines.last().unwrap();
1178
1179        let first_top_left = vec2f(first_line.start_x, start_y);
1180        let first_top_right = vec2f(first_line.end_x, start_y);
1181
1182        let curve_height = vec2f(0., self.corner_radius);
1183        let curve_width = |start_x: f32, end_x: f32| {
1184            let max = (end_x - start_x) / 2.;
1185            let width = if max < self.corner_radius {
1186                max
1187            } else {
1188                self.corner_radius
1189            };
1190
1191            vec2f(width, 0.)
1192        };
1193
1194        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1195        path.reset(first_top_right - top_curve_width);
1196        path.curve_to(first_top_right + curve_height, first_top_right);
1197
1198        let mut iter = lines.iter().enumerate().peekable();
1199        while let Some((ix, line)) = iter.next() {
1200            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1201
1202            if let Some((_, next_line)) = iter.peek() {
1203                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1204
1205                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1206                    Ordering::Equal => {
1207                        path.line_to(bottom_right);
1208                    }
1209                    Ordering::Less => {
1210                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1211                        path.line_to(bottom_right - curve_height);
1212                        if self.corner_radius > 0. {
1213                            path.curve_to(bottom_right - curve_width, bottom_right);
1214                        }
1215                        path.line_to(next_top_right + curve_width);
1216                        if self.corner_radius > 0. {
1217                            path.curve_to(next_top_right + curve_height, next_top_right);
1218                        }
1219                    }
1220                    Ordering::Greater => {
1221                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1222                        path.line_to(bottom_right - curve_height);
1223                        if self.corner_radius > 0. {
1224                            path.curve_to(bottom_right + curve_width, bottom_right);
1225                        }
1226                        path.line_to(next_top_right - curve_width);
1227                        if self.corner_radius > 0. {
1228                            path.curve_to(next_top_right + curve_height, next_top_right);
1229                        }
1230                    }
1231                }
1232            } else {
1233                let curve_width = curve_width(line.start_x, line.end_x);
1234                path.line_to(bottom_right - curve_height);
1235                if self.corner_radius > 0. {
1236                    path.curve_to(bottom_right - curve_width, bottom_right);
1237                }
1238
1239                let bottom_left = vec2f(line.start_x, bottom_right.y());
1240                path.line_to(bottom_left + curve_width);
1241                if self.corner_radius > 0. {
1242                    path.curve_to(bottom_left - curve_height, bottom_left);
1243                }
1244            }
1245        }
1246
1247        if first_line.start_x > last_line.start_x {
1248            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1249            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1250            path.line_to(second_top_left + curve_height);
1251            if self.corner_radius > 0. {
1252                path.curve_to(second_top_left + curve_width, second_top_left);
1253            }
1254            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1255            path.line_to(first_bottom_left - curve_width);
1256            if self.corner_radius > 0. {
1257                path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1258            }
1259        }
1260
1261        path.line_to(first_top_left + curve_height);
1262        if self.corner_radius > 0. {
1263            path.curve_to(first_top_left + top_curve_width, first_top_left);
1264        }
1265        path.line_to(first_top_right - top_curve_width);
1266
1267        scene.push_path(path.build(self.color, Some(bounds)));
1268    }
1269}
1270
1271fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1272    delta.powf(1.5) / 100.0
1273}
1274
1275fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1276    delta.powf(1.2) / 300.0
1277}
1278
1279#[cfg(test)]
1280mod tests {
1281    use super::*;
1282    use crate::{Editor, EditorSettings, MultiBuffer};
1283    use std::sync::Arc;
1284    use util::test::sample_text;
1285
1286    #[gpui::test]
1287    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1288        let settings = EditorSettings::test(cx);
1289        let buffer = MultiBuffer::build_simple(&sample_text(6, 6, 'a'), cx);
1290        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1291            Editor::for_buffer(
1292                buffer,
1293                {
1294                    let settings = settings.clone();
1295                    Arc::new(move |_| settings.clone())
1296                },
1297                cx,
1298            )
1299        });
1300        let element = EditorElement::new(editor.downgrade(), settings);
1301
1302        let layouts = editor.update(cx, |editor, cx| {
1303            let snapshot = editor.snapshot(cx);
1304            let mut presenter = cx.build_presenter(window_id, 30.);
1305            let mut layout_cx = presenter.build_layout_context(false, cx);
1306            element.layout_line_numbers(0..6, &Default::default(), &snapshot, &mut layout_cx)
1307        });
1308        assert_eq!(layouts.len(), 6);
1309    }
1310}