element.rs

   1use crate::display_map::BlockContext;
   2
   3use super::{
   4    DisplayPoint, Editor, EditorMode, EditorSettings, EditorStyle, Input, Scroll, Select,
   5    SelectPhase, Snapshot, SoftWrap, MAX_LINE_LEN,
   6};
   7use clock::ReplicaId;
   8use gpui::{
   9    color::Color,
  10    geometry::{
  11        rect::RectF,
  12        vector::{vec2f, Vector2F},
  13        PathBuilder,
  14    },
  15    json::{self, ToJson},
  16    keymap::Keystroke,
  17    text_layout::{self, RunStyle, TextLayoutCache},
  18    AppContext, Axis, Border, Element, ElementBox, Event, EventContext, FontCache, LayoutContext,
  19    MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext, WeakViewHandle,
  20};
  21use json::json;
  22use language::Chunk;
  23use smallvec::SmallVec;
  24use std::{
  25    cmp::{self, Ordering},
  26    collections::{BTreeMap, HashMap},
  27    fmt::Write,
  28    ops::Range,
  29};
  30
  31pub struct EditorElement {
  32    view: WeakViewHandle<Editor>,
  33    settings: EditorSettings,
  34}
  35
  36impl EditorElement {
  37    pub fn new(view: WeakViewHandle<Editor>, settings: EditorSettings) -> Self {
  38        Self { view, settings }
  39    }
  40
  41    fn view<'a>(&self, cx: &'a AppContext) -> &'a Editor {
  42        self.view.upgrade(cx).unwrap().read(cx)
  43    }
  44
  45    fn update_view<F, T>(&self, cx: &mut MutableAppContext, f: F) -> T
  46    where
  47        F: FnOnce(&mut Editor, &mut ViewContext<Editor>) -> T,
  48    {
  49        self.view.upgrade(cx).unwrap().update(cx, f)
  50    }
  51
  52    fn snapshot(&self, cx: &mut MutableAppContext) -> Snapshot {
  53        self.update_view(cx, |view, cx| view.snapshot(cx))
  54    }
  55
  56    fn mouse_down(
  57        &self,
  58        position: Vector2F,
  59        alt: bool,
  60        shift: bool,
  61        mut click_count: usize,
  62        layout: &mut LayoutState,
  63        paint: &mut PaintState,
  64        cx: &mut EventContext,
  65    ) -> bool {
  66        if paint.gutter_bounds.contains_point(position) {
  67            click_count = 3; // Simulate triple-click when clicking the gutter to select lines
  68        } else if !paint.text_bounds.contains_point(position) {
  69            return false;
  70        }
  71
  72        let snapshot = self.snapshot(cx.app);
  73        let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
  74
  75        if shift && alt {
  76            cx.dispatch_action(Select(SelectPhase::BeginColumnar {
  77                position,
  78                overshoot,
  79            }));
  80        } else if shift {
  81            cx.dispatch_action(Select(SelectPhase::Extend {
  82                position,
  83                click_count,
  84            }));
  85        } else {
  86            cx.dispatch_action(Select(SelectPhase::Begin {
  87                position,
  88                add: alt,
  89                click_count,
  90            }));
  91        }
  92
  93        true
  94    }
  95
  96    fn mouse_up(&self, _position: Vector2F, cx: &mut EventContext) -> bool {
  97        if self.view(cx.app.as_ref()).is_selecting() {
  98            cx.dispatch_action(Select(SelectPhase::End));
  99            true
 100        } else {
 101            false
 102        }
 103    }
 104
 105    fn mouse_dragged(
 106        &self,
 107        position: Vector2F,
 108        layout: &mut LayoutState,
 109        paint: &mut PaintState,
 110        cx: &mut EventContext,
 111    ) -> bool {
 112        let view = self.view(cx.app.as_ref());
 113
 114        if view.is_selecting() {
 115            let rect = paint.text_bounds;
 116            let mut scroll_delta = Vector2F::zero();
 117
 118            let vertical_margin = layout.line_height.min(rect.height() / 3.0);
 119            let top = rect.origin_y() + vertical_margin;
 120            let bottom = rect.lower_left().y() - vertical_margin;
 121            if position.y() < top {
 122                scroll_delta.set_y(-scale_vertical_mouse_autoscroll_delta(top - position.y()))
 123            }
 124            if position.y() > bottom {
 125                scroll_delta.set_y(scale_vertical_mouse_autoscroll_delta(position.y() - bottom))
 126            }
 127
 128            let horizontal_margin = layout.line_height.min(rect.width() / 3.0);
 129            let left = rect.origin_x() + horizontal_margin;
 130            let right = rect.upper_right().x() - horizontal_margin;
 131            if position.x() < left {
 132                scroll_delta.set_x(-scale_horizontal_mouse_autoscroll_delta(
 133                    left - position.x(),
 134                ))
 135            }
 136            if position.x() > right {
 137                scroll_delta.set_x(scale_horizontal_mouse_autoscroll_delta(
 138                    position.x() - right,
 139                ))
 140            }
 141
 142            let font_cache = cx.font_cache.clone();
 143            let text_layout_cache = cx.text_layout_cache.clone();
 144            let snapshot = self.snapshot(cx.app);
 145            let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
 146
 147            cx.dispatch_action(Select(SelectPhase::Update {
 148                position,
 149                overshoot,
 150                scroll_position: (snapshot.scroll_position() + scroll_delta).clamp(
 151                    Vector2F::zero(),
 152                    layout.scroll_max(&font_cache, &text_layout_cache),
 153                ),
 154            }));
 155            true
 156        } else {
 157            false
 158        }
 159    }
 160
 161    fn key_down(&self, chars: &str, keystroke: &Keystroke, cx: &mut EventContext) -> bool {
 162        let view = self.view.upgrade(cx.app).unwrap();
 163
 164        if view.is_focused(cx.app) {
 165            if chars.is_empty() {
 166                false
 167            } else {
 168                if chars.chars().any(|c| c.is_control()) || keystroke.cmd || keystroke.ctrl {
 169                    false
 170                } else {
 171                    cx.dispatch_action(Input(chars.to_string()));
 172                    true
 173                }
 174            }
 175        } else {
 176            false
 177        }
 178    }
 179
 180    fn scroll(
 181        &self,
 182        position: Vector2F,
 183        mut delta: Vector2F,
 184        precise: bool,
 185        layout: &mut LayoutState,
 186        paint: &mut PaintState,
 187        cx: &mut EventContext,
 188    ) -> bool {
 189        if !paint.bounds.contains_point(position) {
 190            return false;
 191        }
 192
 193        let snapshot = self.snapshot(cx.app);
 194        let font_cache = &cx.font_cache;
 195        let layout_cache = &cx.text_layout_cache;
 196        let max_glyph_width = layout.em_width;
 197        if !precise {
 198            delta *= vec2f(max_glyph_width, layout.line_height);
 199        }
 200
 201        let scroll_position = snapshot.scroll_position();
 202        let x = (scroll_position.x() * max_glyph_width - delta.x()) / max_glyph_width;
 203        let y = (scroll_position.y() * layout.line_height - delta.y()) / layout.line_height;
 204        let scroll_position = vec2f(x, y).clamp(
 205            Vector2F::zero(),
 206            layout.scroll_max(font_cache, layout_cache),
 207        );
 208
 209        cx.dispatch_action(Scroll(scroll_position));
 210
 211        true
 212    }
 213
 214    fn paint_background(
 215        &self,
 216        gutter_bounds: RectF,
 217        text_bounds: RectF,
 218        layout: &LayoutState,
 219        cx: &mut PaintContext,
 220    ) {
 221        let bounds = gutter_bounds.union_rect(text_bounds);
 222        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 223        let start_row = layout.snapshot.scroll_position().y() as u32;
 224        let editor = self.view(cx.app);
 225        let style = &self.settings.style;
 226        cx.scene.push_quad(Quad {
 227            bounds: gutter_bounds,
 228            background: Some(style.gutter_background),
 229            border: Border::new(0., Color::transparent_black()),
 230            corner_radius: 0.,
 231        });
 232        cx.scene.push_quad(Quad {
 233            bounds: text_bounds,
 234            background: Some(style.background),
 235            border: Border::new(0., Color::transparent_black()),
 236            corner_radius: 0.,
 237        });
 238
 239        if let EditorMode::Full = editor.mode {
 240            let mut active_rows = layout.active_rows.iter().peekable();
 241            while let Some((start_row, contains_non_empty_selection)) = active_rows.next() {
 242                let mut end_row = *start_row;
 243                while active_rows.peek().map_or(false, |r| {
 244                    *r.0 == end_row + 1 && r.1 == contains_non_empty_selection
 245                }) {
 246                    active_rows.next().unwrap();
 247                    end_row += 1;
 248                }
 249
 250                if !contains_non_empty_selection {
 251                    let origin = vec2f(
 252                        bounds.origin_x(),
 253                        bounds.origin_y() + (layout.line_height * *start_row as f32) - scroll_top,
 254                    );
 255                    let size = vec2f(
 256                        bounds.width(),
 257                        layout.line_height * (end_row - start_row + 1) as f32,
 258                    );
 259                    cx.scene.push_quad(Quad {
 260                        bounds: RectF::new(origin, size),
 261                        background: Some(style.active_line_background),
 262                        border: Border::default(),
 263                        corner_radius: 0.,
 264                    });
 265                }
 266            }
 267
 268            if let Some(highlighted_row) = layout.highlighted_row {
 269                let origin = vec2f(
 270                    bounds.origin_x(),
 271                    bounds.origin_y() + (layout.line_height * highlighted_row as f32) - scroll_top,
 272                );
 273                let size = vec2f(bounds.width(), layout.line_height);
 274                cx.scene.push_quad(Quad {
 275                    bounds: RectF::new(origin, size),
 276                    background: Some(style.highlighted_line_background),
 277                    border: Border::default(),
 278                    corner_radius: 0.,
 279                });
 280            }
 281        }
 282    }
 283
 284    fn paint_gutter(
 285        &mut self,
 286        bounds: RectF,
 287        visible_bounds: RectF,
 288        layout: &LayoutState,
 289        cx: &mut PaintContext,
 290    ) {
 291        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 292        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
 293            if let Some(line) = line {
 294                let line_origin = bounds.origin()
 295                    + vec2f(
 296                        bounds.width() - line.width() - layout.gutter_padding,
 297                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
 298                    );
 299                line.paint(line_origin, visible_bounds, layout.line_height, cx);
 300            }
 301        }
 302    }
 303
 304    fn paint_text(
 305        &mut self,
 306        bounds: RectF,
 307        visible_bounds: RectF,
 308        layout: &LayoutState,
 309        cx: &mut PaintContext,
 310    ) {
 311        let view = self.view(cx.app);
 312        let style = &self.settings.style;
 313        let local_replica_id = view.replica_id(cx);
 314        let scroll_position = layout.snapshot.scroll_position();
 315        let start_row = scroll_position.y() as u32;
 316        let scroll_top = scroll_position.y() * layout.line_height;
 317        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 318        let max_glyph_width = layout.em_width;
 319        let scroll_left = scroll_position.x() * max_glyph_width;
 320
 321        cx.scene.push_layer(Some(bounds));
 322
 323        // Draw selections
 324        let corner_radius = 2.5;
 325        let mut cursors = SmallVec::<[Cursor; 32]>::new();
 326
 327        let content_origin = bounds.origin() + layout.text_offset;
 328
 329        for (replica_id, selections) in &layout.selections {
 330            let style = style.replica_selection_style(*replica_id);
 331
 332            for selection in selections {
 333                if selection.start != selection.end {
 334                    let row_range = if selection.end.column() == 0 {
 335                        cmp::max(selection.start.row(), start_row)
 336                            ..cmp::min(selection.end.row(), end_row)
 337                    } else {
 338                        cmp::max(selection.start.row(), start_row)
 339                            ..cmp::min(selection.end.row() + 1, end_row)
 340                    };
 341
 342                    let selection = Selection {
 343                        color: style.selection,
 344                        line_height: layout.line_height,
 345                        start_y: content_origin.y() + row_range.start as f32 * layout.line_height
 346                            - scroll_top,
 347                        lines: row_range
 348                            .into_iter()
 349                            .map(|row| {
 350                                let line_layout = &layout.line_layouts[(row - start_row) as usize];
 351                                SelectionLine {
 352                                    start_x: if row == selection.start.row() {
 353                                        content_origin.x()
 354                                            + line_layout
 355                                                .x_for_index(selection.start.column() as usize)
 356                                            - scroll_left
 357                                    } else {
 358                                        content_origin.x() - scroll_left
 359                                    },
 360                                    end_x: if row == selection.end.row() {
 361                                        content_origin.x()
 362                                            + line_layout
 363                                                .x_for_index(selection.end.column() as usize)
 364                                            - scroll_left
 365                                    } else {
 366                                        content_origin.x()
 367                                            + line_layout.width()
 368                                            + corner_radius * 2.0
 369                                            - scroll_left
 370                                    },
 371                                }
 372                            })
 373                            .collect(),
 374                    };
 375
 376                    selection.paint(bounds, cx.scene);
 377                }
 378
 379                if view.show_local_cursors() || *replica_id != local_replica_id {
 380                    let cursor_position = selection.head();
 381                    if (start_row..end_row).contains(&cursor_position.row()) {
 382                        let cursor_row_layout =
 383                            &layout.line_layouts[(cursor_position.row() - start_row) as usize];
 384                        let x = cursor_row_layout.x_for_index(cursor_position.column() as usize)
 385                            - scroll_left;
 386                        let y = cursor_position.row() as f32 * layout.line_height - scroll_top;
 387                        cursors.push(Cursor {
 388                            color: style.cursor,
 389                            origin: content_origin + vec2f(x, y),
 390                            line_height: layout.line_height,
 391                        });
 392                    }
 393                }
 394            }
 395        }
 396
 397        if let Some(visible_text_bounds) = bounds.intersection(visible_bounds) {
 398            // Draw glyphs
 399            for (ix, line) in layout.line_layouts.iter().enumerate() {
 400                let row = start_row + ix as u32;
 401                line.paint(
 402                    content_origin
 403                        + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
 404                    visible_text_bounds,
 405                    layout.line_height,
 406                    cx,
 407                );
 408            }
 409        }
 410
 411        cx.scene.push_layer(Some(bounds));
 412        for cursor in cursors {
 413            cursor.paint(cx);
 414        }
 415        cx.scene.pop_layer();
 416
 417        cx.scene.pop_layer();
 418    }
 419
 420    fn paint_blocks(
 421        &mut self,
 422        bounds: RectF,
 423        visible_bounds: RectF,
 424        layout: &LayoutState,
 425        cx: &mut PaintContext,
 426    ) {
 427        for (row_range, block) in &layout.blocks {
 428            //
 429        }
 430    }
 431
 432    fn max_line_number_width(&self, snapshot: &Snapshot, cx: &LayoutContext) -> f32 {
 433        let digit_count = (snapshot.buffer_row_count() as f32).log10().floor() as usize + 1;
 434        let style = &self.settings.style;
 435
 436        cx.text_layout_cache
 437            .layout_str(
 438                "1".repeat(digit_count).as_str(),
 439                style.text.font_size,
 440                &[(
 441                    digit_count,
 442                    RunStyle {
 443                        font_id: style.text.font_id,
 444                        color: Color::black(),
 445                        underline: None,
 446                    },
 447                )],
 448            )
 449            .width()
 450    }
 451
 452    fn layout_rows(
 453        &self,
 454        rows: Range<u32>,
 455        active_rows: &BTreeMap<u32, bool>,
 456        snapshot: &Snapshot,
 457        cx: &LayoutContext,
 458    ) -> Vec<Option<text_layout::Line>> {
 459        let style = &self.settings.style;
 460        let include_line_numbers = snapshot.mode == EditorMode::Full;
 461        let mut line_number_layouts = Vec::with_capacity(rows.len());
 462        let mut line_number = String::new();
 463        for (ix, row) in snapshot
 464            .buffer_rows(rows.start)
 465            .take((rows.end - rows.start) as usize)
 466            .enumerate()
 467        {
 468            let display_row = rows.start + ix as u32;
 469            let color = if active_rows.contains_key(&display_row) {
 470                style.line_number_active
 471            } else {
 472                style.line_number
 473            };
 474            if let Some(buffer_row) = row {
 475                if include_line_numbers {
 476                    line_number.clear();
 477                    write!(&mut line_number, "{}", buffer_row + 1).unwrap();
 478                    line_number_layouts.push(Some(cx.text_layout_cache.layout_str(
 479                        &line_number,
 480                        style.text.font_size,
 481                        &[(
 482                            line_number.len(),
 483                            RunStyle {
 484                                font_id: style.text.font_id,
 485                                color,
 486                                underline: None,
 487                            },
 488                        )],
 489                    )));
 490                }
 491            } else {
 492                line_number_layouts.push(None);
 493            }
 494        }
 495
 496        line_number_layouts
 497    }
 498
 499    fn layout_lines(
 500        &mut self,
 501        mut rows: Range<u32>,
 502        snapshot: &mut Snapshot,
 503        cx: &LayoutContext,
 504    ) -> Vec<text_layout::Line> {
 505        rows.end = cmp::min(rows.end, snapshot.max_point().row() + 1);
 506        if rows.start >= rows.end {
 507            return Vec::new();
 508        }
 509
 510        // When the editor is empty and unfocused, then show the placeholder.
 511        if snapshot.is_empty() && !snapshot.is_focused() {
 512            let placeholder_style = self.settings.style.placeholder_text();
 513            let placeholder_text = snapshot.placeholder_text();
 514            let placeholder_lines = placeholder_text
 515                .as_ref()
 516                .map_or("", AsRef::as_ref)
 517                .split('\n')
 518                .skip(rows.start as usize)
 519                .take(rows.len());
 520            return placeholder_lines
 521                .map(|line| {
 522                    cx.text_layout_cache.layout_str(
 523                        line,
 524                        placeholder_style.font_size,
 525                        &[(
 526                            line.len(),
 527                            RunStyle {
 528                                font_id: placeholder_style.font_id,
 529                                color: placeholder_style.color,
 530                                underline: None,
 531                            },
 532                        )],
 533                    )
 534                })
 535                .collect();
 536        }
 537
 538        let style = &self.settings.style;
 539        let mut prev_font_properties = style.text.font_properties.clone();
 540        let mut prev_font_id = style.text.font_id;
 541
 542        let mut layouts = Vec::with_capacity(rows.len());
 543        let mut line = String::new();
 544        let mut styles = Vec::new();
 545        let mut row = rows.start;
 546        let mut line_exceeded_max_len = false;
 547        let chunks = snapshot.chunks(rows.clone(), Some(&style.syntax));
 548
 549        let newline_chunk = Chunk {
 550            text: "\n",
 551            ..Default::default()
 552        };
 553        'outer: for chunk in chunks.chain([newline_chunk]) {
 554            for (ix, mut line_chunk) in chunk.text.split('\n').enumerate() {
 555                if ix > 0 {
 556                    layouts.push(cx.text_layout_cache.layout_str(
 557                        &line,
 558                        style.text.font_size,
 559                        &styles,
 560                    ));
 561                    line.clear();
 562                    styles.clear();
 563                    row += 1;
 564                    line_exceeded_max_len = false;
 565                    if row == rows.end {
 566                        break 'outer;
 567                    }
 568                }
 569
 570                if !line_chunk.is_empty() && !line_exceeded_max_len {
 571                    let highlight_style =
 572                        chunk.highlight_style.unwrap_or(style.text.clone().into());
 573                    // Avoid a lookup if the font properties match the previous ones.
 574                    let font_id = if highlight_style.font_properties == prev_font_properties {
 575                        prev_font_id
 576                    } else {
 577                        cx.font_cache
 578                            .select_font(
 579                                style.text.font_family_id,
 580                                &highlight_style.font_properties,
 581                            )
 582                            .unwrap_or(style.text.font_id)
 583                    };
 584
 585                    if line.len() + line_chunk.len() > MAX_LINE_LEN {
 586                        let mut chunk_len = MAX_LINE_LEN - line.len();
 587                        while !line_chunk.is_char_boundary(chunk_len) {
 588                            chunk_len -= 1;
 589                        }
 590                        line_chunk = &line_chunk[..chunk_len];
 591                        line_exceeded_max_len = true;
 592                    }
 593
 594                    let underline = if let Some(severity) = chunk.diagnostic {
 595                        Some(super::diagnostic_style(severity, true, style).text)
 596                    } else {
 597                        highlight_style.underline
 598                    };
 599
 600                    line.push_str(line_chunk);
 601                    styles.push((
 602                        line_chunk.len(),
 603                        RunStyle {
 604                            font_id,
 605                            color: highlight_style.color,
 606                            underline,
 607                        },
 608                    ));
 609                    prev_font_id = font_id;
 610                    prev_font_properties = highlight_style.font_properties;
 611                }
 612            }
 613        }
 614
 615        layouts
 616    }
 617
 618    fn layout_blocks(
 619        &mut self,
 620        rows: Range<u32>,
 621        snapshot: &Snapshot,
 622        cx: &LayoutContext,
 623    ) -> Vec<(Range<u32>, ElementBox)> {
 624        snapshot
 625            .blocks_in_range(rows)
 626            .map(|(start_row, block)| {
 627                (
 628                    start_row..start_row + block.height(),
 629                    block.render(&BlockContext {
 630                        cx,
 631                        gutter_width: 0.0,
 632                        anchor_x: 0.0,
 633                    }),
 634                )
 635            })
 636            .collect()
 637    }
 638}
 639
 640impl Element for EditorElement {
 641    type LayoutState = Option<LayoutState>;
 642    type PaintState = Option<PaintState>;
 643
 644    fn layout(
 645        &mut self,
 646        constraint: SizeConstraint,
 647        cx: &mut LayoutContext,
 648    ) -> (Vector2F, Self::LayoutState) {
 649        let mut size = constraint.max;
 650        if size.x().is_infinite() {
 651            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 652        }
 653
 654        let snapshot = self.snapshot(cx.app);
 655        let style = self.settings.style.clone();
 656        let line_height = style.text.line_height(cx.font_cache);
 657
 658        let gutter_padding;
 659        let gutter_width;
 660        if snapshot.mode == EditorMode::Full {
 661            gutter_padding = style.text.em_width(cx.font_cache);
 662            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 663        } else {
 664            gutter_padding = 0.0;
 665            gutter_width = 0.0
 666        };
 667
 668        let text_width = size.x() - gutter_width;
 669        let text_offset = vec2f(-style.text.descent(cx.font_cache), 0.);
 670        let em_width = style.text.em_width(cx.font_cache);
 671        let em_advance = style.text.em_advance(cx.font_cache);
 672        let overscroll = vec2f(em_width, 0.);
 673        let wrap_width = match self.settings.soft_wrap {
 674            SoftWrap::None => None,
 675            SoftWrap::EditorWidth => Some(text_width - text_offset.x() - overscroll.x() - em_width),
 676            SoftWrap::Column(column) => Some(column as f32 * em_advance),
 677        };
 678        let snapshot = self.update_view(cx.app, |view, cx| {
 679            if view.set_wrap_width(wrap_width, cx) {
 680                view.snapshot(cx)
 681            } else {
 682                snapshot
 683            }
 684        });
 685
 686        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
 687        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
 688            size.set_y(
 689                scroll_height
 690                    .min(constraint.max_along(Axis::Vertical))
 691                    .max(constraint.min_along(Axis::Vertical))
 692                    .min(line_height * max_lines as f32),
 693            )
 694        } else if size.y().is_infinite() {
 695            size.set_y(scroll_height);
 696        }
 697        let gutter_size = vec2f(gutter_width, size.y());
 698        let text_size = vec2f(text_width, size.y());
 699
 700        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
 701            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
 702            let snapshot = view.snapshot(cx);
 703            (autoscroll_horizontally, snapshot)
 704        });
 705
 706        let scroll_position = snapshot.scroll_position();
 707        let start_row = scroll_position.y() as u32;
 708        let scroll_top = scroll_position.y() * line_height;
 709        let end_row = ((scroll_top + size.y()) / line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 710
 711        let mut selections = HashMap::new();
 712        let mut active_rows = BTreeMap::new();
 713        let mut highlighted_row = None;
 714        self.update_view(cx.app, |view, cx| {
 715            highlighted_row = view.highlighted_row();
 716            for selection_set_id in view.active_selection_sets(cx).collect::<Vec<_>>() {
 717                let replica_selections = view
 718                    .intersecting_selections(
 719                        selection_set_id,
 720                        DisplayPoint::new(start_row, 0)..DisplayPoint::new(end_row, 0),
 721                        cx,
 722                    )
 723                    .collect::<Vec<_>>();
 724                for selection in &replica_selections {
 725                    if selection_set_id == view.selection_set_id {
 726                        let is_empty = selection.start == selection.end;
 727                        let selection_start = snapshot.prev_row_boundary(selection.start).0;
 728                        let selection_end = snapshot.next_row_boundary(selection.end).0;
 729                        for row in cmp::max(selection_start.row(), start_row)
 730                            ..=cmp::min(selection_end.row(), end_row)
 731                        {
 732                            let contains_non_empty_selection =
 733                                active_rows.entry(row).or_insert(!is_empty);
 734                            *contains_non_empty_selection |= !is_empty;
 735                        }
 736                    }
 737                }
 738
 739                selections.insert(selection_set_id.replica_id, replica_selections);
 740            }
 741        });
 742
 743        let line_number_layouts = self.layout_rows(start_row..end_row, &active_rows, &snapshot, cx);
 744
 745        let mut max_visible_line_width = 0.0;
 746        let line_layouts = self.layout_lines(start_row..end_row, &mut snapshot, cx);
 747        for line in &line_layouts {
 748            if line.width() > max_visible_line_width {
 749                max_visible_line_width = line.width();
 750            }
 751        }
 752
 753        let blocks = self.layout_blocks(start_row..end_row, &snapshot, cx);
 754
 755        let mut layout = LayoutState {
 756            size,
 757            gutter_size,
 758            gutter_padding,
 759            text_size,
 760            overscroll,
 761            text_offset,
 762            snapshot,
 763            style: self.settings.style.clone(),
 764            active_rows,
 765            highlighted_row,
 766            line_layouts,
 767            line_number_layouts,
 768            blocks,
 769            line_height,
 770            em_width,
 771            em_advance,
 772            selections,
 773            max_visible_line_width,
 774        };
 775
 776        let scroll_max = layout.scroll_max(cx.font_cache, cx.text_layout_cache).x();
 777        let scroll_width = layout.scroll_width(cx.text_layout_cache);
 778        let max_glyph_width = style.text.em_width(&cx.font_cache);
 779        self.update_view(cx.app, |view, cx| {
 780            let clamped = view.clamp_scroll_left(scroll_max);
 781            let autoscrolled;
 782            if autoscroll_horizontally {
 783                autoscrolled = view.autoscroll_horizontally(
 784                    start_row,
 785                    layout.text_size.x(),
 786                    scroll_width,
 787                    max_glyph_width,
 788                    &layout.line_layouts,
 789                    cx,
 790                );
 791            } else {
 792                autoscrolled = false;
 793            }
 794
 795            if clamped || autoscrolled {
 796                layout.snapshot = view.snapshot(cx);
 797            }
 798        });
 799
 800        (size, Some(layout))
 801    }
 802
 803    fn paint(
 804        &mut self,
 805        bounds: RectF,
 806        visible_bounds: RectF,
 807        layout: &mut Self::LayoutState,
 808        cx: &mut PaintContext,
 809    ) -> Self::PaintState {
 810        if let Some(layout) = layout {
 811            cx.scene.push_layer(Some(bounds));
 812
 813            let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
 814            let text_bounds = RectF::new(
 815                bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
 816                layout.text_size,
 817            );
 818
 819            self.paint_background(gutter_bounds, text_bounds, layout, cx);
 820            if layout.gutter_size.x() > 0. {
 821                self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
 822            }
 823            self.paint_text(text_bounds, visible_bounds, layout, cx);
 824            self.paint_blocks(text_bounds, visible_bounds, layout, cx);
 825
 826            cx.scene.pop_layer();
 827
 828            Some(PaintState {
 829                bounds,
 830                gutter_bounds,
 831                text_bounds,
 832            })
 833        } else {
 834            None
 835        }
 836    }
 837
 838    fn dispatch_event(
 839        &mut self,
 840        event: &Event,
 841        _: RectF,
 842        layout: &mut Self::LayoutState,
 843        paint: &mut Self::PaintState,
 844        cx: &mut EventContext,
 845    ) -> bool {
 846        if let (Some(layout), Some(paint)) = (layout, paint) {
 847            match event {
 848                Event::LeftMouseDown {
 849                    position,
 850                    alt,
 851                    shift,
 852                    click_count,
 853                    ..
 854                } => self.mouse_down(*position, *alt, *shift, *click_count, layout, paint, cx),
 855                Event::LeftMouseUp { position } => self.mouse_up(*position, cx),
 856                Event::LeftMouseDragged { position } => {
 857                    self.mouse_dragged(*position, layout, paint, cx)
 858                }
 859                Event::ScrollWheel {
 860                    position,
 861                    delta,
 862                    precise,
 863                } => self.scroll(*position, *delta, *precise, layout, paint, cx),
 864                Event::KeyDown {
 865                    chars, keystroke, ..
 866                } => self.key_down(chars, keystroke, cx),
 867                _ => false,
 868            }
 869        } else {
 870            false
 871        }
 872    }
 873
 874    fn debug(
 875        &self,
 876        bounds: RectF,
 877        _: &Self::LayoutState,
 878        _: &Self::PaintState,
 879        _: &gpui::DebugContext,
 880    ) -> json::Value {
 881        json!({
 882            "type": "BufferElement",
 883            "bounds": bounds.to_json()
 884        })
 885    }
 886}
 887
 888pub struct LayoutState {
 889    size: Vector2F,
 890    gutter_size: Vector2F,
 891    gutter_padding: f32,
 892    text_size: Vector2F,
 893    style: EditorStyle,
 894    snapshot: Snapshot,
 895    active_rows: BTreeMap<u32, bool>,
 896    highlighted_row: Option<u32>,
 897    line_layouts: Vec<text_layout::Line>,
 898    line_number_layouts: Vec<Option<text_layout::Line>>,
 899    blocks: Vec<(Range<u32>, ElementBox)>,
 900    line_height: f32,
 901    em_width: f32,
 902    em_advance: f32,
 903    selections: HashMap<ReplicaId, Vec<text::Selection<DisplayPoint>>>,
 904    overscroll: Vector2F,
 905    text_offset: Vector2F,
 906    max_visible_line_width: f32,
 907}
 908
 909impl LayoutState {
 910    fn scroll_width(&self, layout_cache: &TextLayoutCache) -> f32 {
 911        let row = self.snapshot.longest_row();
 912        let longest_line_width = self.layout_line(row, &self.snapshot, layout_cache).width();
 913        longest_line_width.max(self.max_visible_line_width) + self.overscroll.x()
 914    }
 915
 916    fn scroll_max(&self, font_cache: &FontCache, layout_cache: &TextLayoutCache) -> Vector2F {
 917        let text_width = self.text_size.x();
 918        let scroll_width = self.scroll_width(layout_cache);
 919        let em_width = self.style.text.em_width(font_cache);
 920        let max_row = self.snapshot.max_point().row();
 921
 922        vec2f(
 923            ((scroll_width - text_width) / em_width).max(0.0),
 924            max_row.saturating_sub(1) as f32,
 925        )
 926    }
 927
 928    pub fn layout_line(
 929        &self,
 930        row: u32,
 931        snapshot: &Snapshot,
 932        layout_cache: &TextLayoutCache,
 933    ) -> text_layout::Line {
 934        let mut line = snapshot.line(row);
 935
 936        if line.len() > MAX_LINE_LEN {
 937            let mut len = MAX_LINE_LEN;
 938            while !line.is_char_boundary(len) {
 939                len -= 1;
 940            }
 941            line.truncate(len);
 942        }
 943
 944        layout_cache.layout_str(
 945            &line,
 946            self.style.text.font_size,
 947            &[(
 948                snapshot.line_len(row) as usize,
 949                RunStyle {
 950                    font_id: self.style.text.font_id,
 951                    color: Color::black(),
 952                    underline: None,
 953                },
 954            )],
 955        )
 956    }
 957}
 958
 959pub struct PaintState {
 960    bounds: RectF,
 961    gutter_bounds: RectF,
 962    text_bounds: RectF,
 963}
 964
 965impl PaintState {
 966    fn point_for_position(
 967        &self,
 968        snapshot: &Snapshot,
 969        layout: &LayoutState,
 970        position: Vector2F,
 971    ) -> (DisplayPoint, u32) {
 972        let scroll_position = snapshot.scroll_position();
 973        let position = position - self.text_bounds.origin();
 974        let y = position.y().max(0.0).min(layout.size.y());
 975        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
 976        let row = cmp::min(row, snapshot.max_point().row());
 977        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
 978        let x = position.x() + (scroll_position.x() * layout.em_width);
 979
 980        let column = if x >= 0.0 {
 981            line.index_for_x(x)
 982                .map(|ix| ix as u32)
 983                .unwrap_or_else(|| snapshot.line_len(row))
 984        } else {
 985            0
 986        };
 987        let overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
 988
 989        (DisplayPoint::new(row, column), overshoot)
 990    }
 991}
 992
 993struct Cursor {
 994    origin: Vector2F,
 995    line_height: f32,
 996    color: Color,
 997}
 998
 999impl Cursor {
1000    fn paint(&self, cx: &mut PaintContext) {
1001        cx.scene.push_quad(Quad {
1002            bounds: RectF::new(self.origin, vec2f(2.0, self.line_height)),
1003            background: Some(self.color),
1004            border: Border::new(0., Color::black()),
1005            corner_radius: 0.,
1006        });
1007    }
1008}
1009
1010#[derive(Debug)]
1011struct Selection {
1012    start_y: f32,
1013    line_height: f32,
1014    lines: Vec<SelectionLine>,
1015    color: Color,
1016}
1017
1018#[derive(Debug)]
1019struct SelectionLine {
1020    start_x: f32,
1021    end_x: f32,
1022}
1023
1024impl Selection {
1025    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1026        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1027            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1028            self.paint_lines(
1029                self.start_y + self.line_height,
1030                &self.lines[1..],
1031                bounds,
1032                scene,
1033            );
1034        } else {
1035            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1036        }
1037    }
1038
1039    fn paint_lines(&self, start_y: f32, lines: &[SelectionLine], bounds: RectF, scene: &mut Scene) {
1040        if lines.is_empty() {
1041            return;
1042        }
1043
1044        let mut path = PathBuilder::new();
1045        let corner_radius = 0.15 * self.line_height;
1046        let first_line = lines.first().unwrap();
1047        let last_line = lines.last().unwrap();
1048
1049        let first_top_left = vec2f(first_line.start_x, start_y);
1050        let first_top_right = vec2f(first_line.end_x, start_y);
1051
1052        let curve_height = vec2f(0., corner_radius);
1053        let curve_width = |start_x: f32, end_x: f32| {
1054            let max = (end_x - start_x) / 2.;
1055            let width = if max < corner_radius {
1056                max
1057            } else {
1058                corner_radius
1059            };
1060
1061            vec2f(width, 0.)
1062        };
1063
1064        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1065        path.reset(first_top_right - top_curve_width);
1066        path.curve_to(first_top_right + curve_height, first_top_right);
1067
1068        let mut iter = lines.iter().enumerate().peekable();
1069        while let Some((ix, line)) = iter.next() {
1070            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1071
1072            if let Some((_, next_line)) = iter.peek() {
1073                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1074
1075                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1076                    Ordering::Equal => {
1077                        path.line_to(bottom_right);
1078                    }
1079                    Ordering::Less => {
1080                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1081                        path.line_to(bottom_right - curve_height);
1082                        path.curve_to(bottom_right - curve_width, bottom_right);
1083                        path.line_to(next_top_right + curve_width);
1084                        path.curve_to(next_top_right + curve_height, next_top_right);
1085                    }
1086                    Ordering::Greater => {
1087                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1088                        path.line_to(bottom_right - curve_height);
1089                        path.curve_to(bottom_right + curve_width, bottom_right);
1090                        path.line_to(next_top_right - curve_width);
1091                        path.curve_to(next_top_right + curve_height, next_top_right);
1092                    }
1093                }
1094            } else {
1095                let curve_width = curve_width(line.start_x, line.end_x);
1096                path.line_to(bottom_right - curve_height);
1097                path.curve_to(bottom_right - curve_width, bottom_right);
1098
1099                let bottom_left = vec2f(line.start_x, bottom_right.y());
1100                path.line_to(bottom_left + curve_width);
1101                path.curve_to(bottom_left - curve_height, bottom_left);
1102            }
1103        }
1104
1105        if first_line.start_x > last_line.start_x {
1106            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1107            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1108            path.line_to(second_top_left + curve_height);
1109            path.curve_to(second_top_left + curve_width, second_top_left);
1110            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1111            path.line_to(first_bottom_left - curve_width);
1112            path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1113        }
1114
1115        path.line_to(first_top_left + curve_height);
1116        path.curve_to(first_top_left + top_curve_width, first_top_left);
1117        path.line_to(first_top_right - top_curve_width);
1118
1119        scene.push_path(path.build(self.color, Some(bounds)));
1120    }
1121}
1122
1123fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1124    delta.powf(1.5) / 100.0
1125}
1126
1127fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1128    delta.powf(1.2) / 300.0
1129}
1130
1131#[cfg(test)]
1132mod tests {
1133    use super::*;
1134    use crate::{
1135        test::sample_text,
1136        {Editor, EditorSettings},
1137    };
1138    use language::Buffer;
1139
1140    #[gpui::test]
1141    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1142        let settings = EditorSettings::test(cx);
1143
1144        let buffer = cx.add_model(|cx| Buffer::new(0, sample_text(6, 6), cx));
1145        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1146            Editor::for_buffer(
1147                buffer,
1148                {
1149                    let settings = settings.clone();
1150                    move |_| settings.clone()
1151                },
1152                cx,
1153            )
1154        });
1155        let element = EditorElement::new(editor.downgrade(), settings);
1156
1157        let layouts = editor.update(cx, |editor, cx| {
1158            let snapshot = editor.snapshot(cx);
1159            let mut presenter = cx.build_presenter(window_id, 30.);
1160            let mut layout_cx = presenter.build_layout_context(false, cx);
1161            element.layout_rows(0..6, &Default::default(), &snapshot, &mut layout_cx)
1162        });
1163        assert_eq!(layouts.len(), 6);
1164    }
1165}