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    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::{Bias, Chunk};
  23use smallvec::SmallVec;
  24use std::{
  25    cmp::{self, Ordering},
  26    fmt::Write,
  27    ops::Range,
  28};
  29
  30pub struct EditorElement {
  31    view: WeakViewHandle<Editor>,
  32    settings: EditorSettings,
  33}
  34
  35impl EditorElement {
  36    pub fn new(view: WeakViewHandle<Editor>, settings: EditorSettings) -> Self {
  37        Self { view, settings }
  38    }
  39
  40    fn view<'a>(&self, cx: &'a AppContext) -> &'a Editor {
  41        self.view.upgrade(cx).unwrap().read(cx)
  42    }
  43
  44    fn update_view<F, T>(&self, cx: &mut MutableAppContext, f: F) -> T
  45    where
  46        F: FnOnce(&mut Editor, &mut ViewContext<Editor>) -> T,
  47    {
  48        self.view.upgrade(cx).unwrap().update(cx, f)
  49    }
  50
  51    fn snapshot(&self, cx: &mut MutableAppContext) -> EditorSnapshot {
  52        self.update_view(cx, |view, cx| view.snapshot(cx))
  53    }
  54
  55    fn mouse_down(
  56        &self,
  57        position: Vector2F,
  58        alt: bool,
  59        shift: bool,
  60        mut click_count: usize,
  61        layout: &mut LayoutState,
  62        paint: &mut PaintState,
  63        cx: &mut EventContext,
  64    ) -> bool {
  65        if paint.gutter_bounds.contains_point(position) {
  66            click_count = 3; // Simulate triple-click when clicking the gutter to select lines
  67        } else if !paint.text_bounds.contains_point(position) {
  68            return false;
  69        }
  70
  71        let snapshot = self.snapshot(cx.app);
  72        let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
  73
  74        if shift && alt {
  75            cx.dispatch_action(Select(SelectPhase::BeginColumnar {
  76                position,
  77                overshoot,
  78            }));
  79        } else if shift {
  80            cx.dispatch_action(Select(SelectPhase::Extend {
  81                position,
  82                click_count,
  83            }));
  84        } else {
  85            cx.dispatch_action(Select(SelectPhase::Begin {
  86                position,
  87                add: alt,
  88                click_count,
  89            }));
  90        }
  91
  92        true
  93    }
  94
  95    fn mouse_up(&self, _position: Vector2F, cx: &mut EventContext) -> bool {
  96        if self.view(cx.app.as_ref()).is_selecting() {
  97            cx.dispatch_action(Select(SelectPhase::End));
  98            true
  99        } else {
 100            false
 101        }
 102    }
 103
 104    fn mouse_dragged(
 105        &self,
 106        position: Vector2F,
 107        layout: &mut LayoutState,
 108        paint: &mut PaintState,
 109        cx: &mut EventContext,
 110    ) -> bool {
 111        let view = self.view(cx.app.as_ref());
 112
 113        if view.is_selecting() {
 114            let rect = paint.text_bounds;
 115            let mut scroll_delta = Vector2F::zero();
 116
 117            let vertical_margin = layout.line_height.min(rect.height() / 3.0);
 118            let top = rect.origin_y() + vertical_margin;
 119            let bottom = rect.lower_left().y() - vertical_margin;
 120            if position.y() < top {
 121                scroll_delta.set_y(-scale_vertical_mouse_autoscroll_delta(top - position.y()))
 122            }
 123            if position.y() > bottom {
 124                scroll_delta.set_y(scale_vertical_mouse_autoscroll_delta(position.y() - bottom))
 125            }
 126
 127            let horizontal_margin = layout.line_height.min(rect.width() / 3.0);
 128            let left = rect.origin_x() + horizontal_margin;
 129            let right = rect.upper_right().x() - horizontal_margin;
 130            if position.x() < left {
 131                scroll_delta.set_x(-scale_horizontal_mouse_autoscroll_delta(
 132                    left - position.x(),
 133                ))
 134            }
 135            if position.x() > right {
 136                scroll_delta.set_x(scale_horizontal_mouse_autoscroll_delta(
 137                    position.x() - right,
 138                ))
 139            }
 140
 141            let font_cache = cx.font_cache.clone();
 142            let text_layout_cache = cx.text_layout_cache.clone();
 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).clamp(
 150                    Vector2F::zero(),
 151                    layout.scroll_max(&font_cache, &text_layout_cache),
 152                ),
 153            }));
 154            true
 155        } else {
 156            false
 157        }
 158    }
 159
 160    fn key_down(&self, chars: &str, keystroke: &Keystroke, cx: &mut EventContext) -> bool {
 161        let view = self.view.upgrade(cx.app).unwrap();
 162
 163        if view.is_focused(cx.app) {
 164            if chars.is_empty() {
 165                false
 166            } else {
 167                if chars.chars().any(|c| c.is_control()) || keystroke.cmd || keystroke.ctrl {
 168                    false
 169                } else {
 170                    cx.dispatch_action(Input(chars.to_string()));
 171                    true
 172                }
 173            }
 174        } else {
 175            false
 176        }
 177    }
 178
 179    fn scroll(
 180        &self,
 181        position: Vector2F,
 182        mut delta: Vector2F,
 183        precise: bool,
 184        layout: &mut LayoutState,
 185        paint: &mut PaintState,
 186        cx: &mut EventContext,
 187    ) -> bool {
 188        if !paint.bounds.contains_point(position) {
 189            return false;
 190        }
 191
 192        let snapshot = self.snapshot(cx.app);
 193        let font_cache = &cx.font_cache;
 194        let layout_cache = &cx.text_layout_cache;
 195        let max_glyph_width = layout.em_width;
 196        if !precise {
 197            delta *= vec2f(max_glyph_width, layout.line_height);
 198        }
 199
 200        let scroll_position = snapshot.scroll_position();
 201        let x = (scroll_position.x() * max_glyph_width - delta.x()) / max_glyph_width;
 202        let y = (scroll_position.y() * layout.line_height - delta.y()) / layout.line_height;
 203        let scroll_position = vec2f(x, y).clamp(
 204            Vector2F::zero(),
 205            layout.scroll_max(font_cache, layout_cache),
 206        );
 207
 208        cx.dispatch_action(Scroll(scroll_position));
 209
 210        true
 211    }
 212
 213    fn paint_background(
 214        &self,
 215        gutter_bounds: RectF,
 216        text_bounds: RectF,
 217        layout: &LayoutState,
 218        cx: &mut PaintContext,
 219    ) {
 220        let bounds = gutter_bounds.union_rect(text_bounds);
 221        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 222        let editor = self.view(cx.app);
 223        let style = &self.settings.style;
 224        cx.scene.push_quad(Quad {
 225            bounds: gutter_bounds,
 226            background: Some(style.gutter_background),
 227            border: Border::new(0., Color::transparent_black()),
 228            corner_radius: 0.,
 229        });
 230        cx.scene.push_quad(Quad {
 231            bounds: text_bounds,
 232            background: Some(style.background),
 233            border: Border::new(0., Color::transparent_black()),
 234            corner_radius: 0.,
 235        });
 236
 237        if let EditorMode::Full = editor.mode {
 238            let mut active_rows = layout.active_rows.iter().peekable();
 239            while let Some((start_row, contains_non_empty_selection)) = active_rows.next() {
 240                let mut end_row = *start_row;
 241                while active_rows.peek().map_or(false, |r| {
 242                    *r.0 == end_row + 1 && r.1 == contains_non_empty_selection
 243                }) {
 244                    active_rows.next().unwrap();
 245                    end_row += 1;
 246                }
 247
 248                if !contains_non_empty_selection {
 249                    let origin = vec2f(
 250                        bounds.origin_x(),
 251                        bounds.origin_y() + (layout.line_height * *start_row as f32) - scroll_top,
 252                    );
 253                    let size = vec2f(
 254                        bounds.width(),
 255                        layout.line_height * (end_row - start_row + 1) as f32,
 256                    );
 257                    cx.scene.push_quad(Quad {
 258                        bounds: RectF::new(origin, size),
 259                        background: Some(style.active_line_background),
 260                        border: Border::default(),
 261                        corner_radius: 0.,
 262                    });
 263                }
 264            }
 265
 266            if let Some(highlighted_row) = layout.highlighted_row {
 267                let origin = vec2f(
 268                    bounds.origin_x(),
 269                    bounds.origin_y() + (layout.line_height * highlighted_row as f32) - scroll_top,
 270                );
 271                let size = vec2f(bounds.width(), layout.line_height);
 272                cx.scene.push_quad(Quad {
 273                    bounds: RectF::new(origin, size),
 274                    background: Some(style.highlighted_line_background),
 275                    border: Border::default(),
 276                    corner_radius: 0.,
 277                });
 278            }
 279        }
 280    }
 281
 282    fn paint_gutter(
 283        &mut self,
 284        bounds: RectF,
 285        visible_bounds: RectF,
 286        layout: &LayoutState,
 287        cx: &mut PaintContext,
 288    ) {
 289        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 290        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
 291            if let Some(line) = line {
 292                let line_origin = bounds.origin()
 293                    + vec2f(
 294                        bounds.width() - line.width() - layout.gutter_padding,
 295                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
 296                    );
 297                line.paint(line_origin, visible_bounds, layout.line_height, cx);
 298            }
 299        }
 300    }
 301
 302    fn paint_text(
 303        &mut self,
 304        bounds: RectF,
 305        visible_bounds: RectF,
 306        layout: &LayoutState,
 307        cx: &mut PaintContext,
 308    ) {
 309        let view = self.view(cx.app);
 310        let style = &self.settings.style;
 311        let local_replica_id = view.replica_id(cx);
 312        let scroll_position = layout.snapshot.scroll_position();
 313        let start_row = scroll_position.y() as u32;
 314        let scroll_top = scroll_position.y() * layout.line_height;
 315        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 316        let max_glyph_width = layout.em_width;
 317        let scroll_left = scroll_position.x() * max_glyph_width;
 318
 319        cx.scene.push_layer(Some(bounds));
 320
 321        // Draw selections
 322        let corner_radius = 2.5;
 323        let mut cursors = SmallVec::<[Cursor; 32]>::new();
 324
 325        let content_origin = bounds.origin() + layout.text_offset;
 326
 327        for (replica_id, selections) in &layout.selections {
 328            let style = style.replica_selection_style(*replica_id);
 329
 330            for selection in selections {
 331                if selection.start != selection.end {
 332                    let row_range = if selection.end.column() == 0 {
 333                        cmp::max(selection.start.row(), start_row)
 334                            ..cmp::min(selection.end.row(), end_row)
 335                    } else {
 336                        cmp::max(selection.start.row(), start_row)
 337                            ..cmp::min(selection.end.row() + 1, end_row)
 338                    };
 339
 340                    let selection = Selection {
 341                        color: style.selection,
 342                        line_height: layout.line_height,
 343                        start_y: content_origin.y() + row_range.start as f32 * layout.line_height
 344                            - scroll_top,
 345                        lines: row_range
 346                            .into_iter()
 347                            .map(|row| {
 348                                let line_layout = &layout.line_layouts[(row - start_row) as usize];
 349                                SelectionLine {
 350                                    start_x: if row == selection.start.row() {
 351                                        content_origin.x()
 352                                            + line_layout
 353                                                .x_for_index(selection.start.column() as usize)
 354                                            - scroll_left
 355                                    } else {
 356                                        content_origin.x() - scroll_left
 357                                    },
 358                                    end_x: if row == selection.end.row() {
 359                                        content_origin.x()
 360                                            + line_layout
 361                                                .x_for_index(selection.end.column() as usize)
 362                                            - scroll_left
 363                                    } else {
 364                                        content_origin.x()
 365                                            + line_layout.width()
 366                                            + corner_radius * 2.0
 367                                            - scroll_left
 368                                    },
 369                                }
 370                            })
 371                            .collect(),
 372                    };
 373
 374                    selection.paint(bounds, cx.scene);
 375                }
 376
 377                if view.show_local_cursors() || *replica_id != local_replica_id {
 378                    let cursor_position = selection.head();
 379                    if (start_row..end_row).contains(&cursor_position.row()) {
 380                        let cursor_row_layout =
 381                            &layout.line_layouts[(cursor_position.row() - start_row) as usize];
 382                        let x = cursor_row_layout.x_for_index(cursor_position.column() as usize)
 383                            - scroll_left;
 384                        let y = cursor_position.row() as f32 * layout.line_height - scroll_top;
 385                        cursors.push(Cursor {
 386                            color: style.cursor,
 387                            origin: content_origin + vec2f(x, y),
 388                            line_height: layout.line_height,
 389                        });
 390                    }
 391                }
 392            }
 393        }
 394
 395        if let Some(visible_text_bounds) = bounds.intersection(visible_bounds) {
 396            // Draw glyphs
 397            for (ix, line) in layout.line_layouts.iter().enumerate() {
 398                let row = start_row + ix as u32;
 399                line.paint(
 400                    content_origin
 401                        + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
 402                    visible_text_bounds,
 403                    layout.line_height,
 404                    cx,
 405                );
 406            }
 407        }
 408
 409        cx.scene.push_layer(Some(bounds));
 410        for cursor in cursors {
 411            cursor.paint(cx);
 412        }
 413        cx.scene.pop_layer();
 414
 415        cx.scene.pop_layer();
 416    }
 417
 418    fn paint_blocks(
 419        &mut self,
 420        bounds: RectF,
 421        visible_bounds: RectF,
 422        layout: &mut LayoutState,
 423        cx: &mut PaintContext,
 424    ) {
 425        let scroll_position = layout.snapshot.scroll_position();
 426        let scroll_left = scroll_position.x() * layout.em_width;
 427        let scroll_top = scroll_position.y() * layout.line_height;
 428
 429        for (row, element) in &mut layout.blocks {
 430            let origin = bounds.origin()
 431                + vec2f(-scroll_left, *row as f32 * layout.line_height - scroll_top);
 432            element.paint(origin, visible_bounds, cx);
 433        }
 434    }
 435
 436    fn max_line_number_width(&self, snapshot: &EditorSnapshot, cx: &LayoutContext) -> f32 {
 437        let digit_count = (snapshot.max_buffer_row() as f32).log10().floor() as usize + 1;
 438        let style = &self.settings.style;
 439
 440        cx.text_layout_cache
 441            .layout_str(
 442                "1".repeat(digit_count).as_str(),
 443                style.text.font_size,
 444                &[(
 445                    digit_count,
 446                    RunStyle {
 447                        font_id: style.text.font_id,
 448                        color: Color::black(),
 449                        underline: None,
 450                    },
 451                )],
 452            )
 453            .width()
 454    }
 455
 456    fn layout_rows(
 457        &self,
 458        rows: Range<u32>,
 459        active_rows: &BTreeMap<u32, bool>,
 460        snapshot: &EditorSnapshot,
 461        cx: &LayoutContext,
 462    ) -> Vec<Option<text_layout::Line>> {
 463        let style = &self.settings.style;
 464        let include_line_numbers = snapshot.mode == EditorMode::Full;
 465        let mut line_number_layouts = Vec::with_capacity(rows.len());
 466        let mut line_number = String::new();
 467        for (ix, row) in snapshot
 468            .buffer_rows(rows.start)
 469            .take((rows.end - rows.start) as usize)
 470            .enumerate()
 471        {
 472            let display_row = rows.start + ix as u32;
 473            let color = if active_rows.contains_key(&display_row) {
 474                style.line_number_active
 475            } else {
 476                style.line_number
 477            };
 478            if let Some(buffer_row) = row {
 479                if include_line_numbers {
 480                    line_number.clear();
 481                    write!(&mut line_number, "{}", buffer_row + 1).unwrap();
 482                    line_number_layouts.push(Some(cx.text_layout_cache.layout_str(
 483                        &line_number,
 484                        style.text.font_size,
 485                        &[(
 486                            line_number.len(),
 487                            RunStyle {
 488                                font_id: style.text.font_id,
 489                                color,
 490                                underline: None,
 491                            },
 492                        )],
 493                    )));
 494                }
 495            } else {
 496                line_number_layouts.push(None);
 497            }
 498        }
 499
 500        line_number_layouts
 501    }
 502
 503    fn layout_lines(
 504        &mut self,
 505        mut rows: Range<u32>,
 506        snapshot: &mut EditorSnapshot,
 507        cx: &LayoutContext,
 508    ) -> Vec<text_layout::Line> {
 509        rows.end = cmp::min(rows.end, snapshot.max_point().row() + 1);
 510        if rows.start >= rows.end {
 511            return Vec::new();
 512        }
 513
 514        // When the editor is empty and unfocused, then show the placeholder.
 515        if snapshot.is_empty() && !snapshot.is_focused() {
 516            let placeholder_style = self.settings.style.placeholder_text();
 517            let placeholder_text = snapshot.placeholder_text();
 518            let placeholder_lines = placeholder_text
 519                .as_ref()
 520                .map_or("", AsRef::as_ref)
 521                .split('\n')
 522                .skip(rows.start as usize)
 523                .take(rows.len());
 524            return placeholder_lines
 525                .map(|line| {
 526                    cx.text_layout_cache.layout_str(
 527                        line,
 528                        placeholder_style.font_size,
 529                        &[(
 530                            line.len(),
 531                            RunStyle {
 532                                font_id: placeholder_style.font_id,
 533                                color: placeholder_style.color,
 534                                underline: None,
 535                            },
 536                        )],
 537                    )
 538                })
 539                .collect();
 540        }
 541
 542        let style = &self.settings.style;
 543        let mut prev_font_properties = style.text.font_properties.clone();
 544        let mut prev_font_id = style.text.font_id;
 545
 546        let mut layouts = Vec::with_capacity(rows.len());
 547        let mut line = String::new();
 548        let mut styles = Vec::new();
 549        let mut row = rows.start;
 550        let mut line_exceeded_max_len = false;
 551        let chunks = snapshot.chunks(rows.clone(), Some(&style.syntax));
 552
 553        let newline_chunk = Chunk {
 554            text: "\n",
 555            ..Default::default()
 556        };
 557        'outer: for chunk in chunks.chain([newline_chunk]) {
 558            for (ix, mut line_chunk) in chunk.text.split('\n').enumerate() {
 559                if ix > 0 {
 560                    layouts.push(cx.text_layout_cache.layout_str(
 561                        &line,
 562                        style.text.font_size,
 563                        &styles,
 564                    ));
 565                    line.clear();
 566                    styles.clear();
 567                    row += 1;
 568                    line_exceeded_max_len = false;
 569                    if row == rows.end {
 570                        break 'outer;
 571                    }
 572                }
 573
 574                if !line_chunk.is_empty() && !line_exceeded_max_len {
 575                    let highlight_style =
 576                        chunk.highlight_style.unwrap_or(style.text.clone().into());
 577                    // Avoid a lookup if the font properties match the previous ones.
 578                    let font_id = if highlight_style.font_properties == prev_font_properties {
 579                        prev_font_id
 580                    } else {
 581                        cx.font_cache
 582                            .select_font(
 583                                style.text.font_family_id,
 584                                &highlight_style.font_properties,
 585                            )
 586                            .unwrap_or(style.text.font_id)
 587                    };
 588
 589                    if line.len() + line_chunk.len() > MAX_LINE_LEN {
 590                        let mut chunk_len = MAX_LINE_LEN - line.len();
 591                        while !line_chunk.is_char_boundary(chunk_len) {
 592                            chunk_len -= 1;
 593                        }
 594                        line_chunk = &line_chunk[..chunk_len];
 595                        line_exceeded_max_len = true;
 596                    }
 597
 598                    let underline = if let Some(severity) = chunk.diagnostic {
 599                        Some(super::diagnostic_style(severity, true, style).text)
 600                    } else {
 601                        highlight_style.underline
 602                    };
 603
 604                    line.push_str(line_chunk);
 605                    styles.push((
 606                        line_chunk.len(),
 607                        RunStyle {
 608                            font_id,
 609                            color: highlight_style.color,
 610                            underline,
 611                        },
 612                    ));
 613                    prev_font_id = font_id;
 614                    prev_font_properties = highlight_style.font_properties;
 615                }
 616            }
 617        }
 618
 619        layouts
 620    }
 621
 622    fn layout_blocks(
 623        &mut self,
 624        rows: Range<u32>,
 625        snapshot: &EditorSnapshot,
 626        width: f32,
 627        line_number_x: f32,
 628        text_x: f32,
 629        line_height: f32,
 630        style: &EditorStyle,
 631        line_layouts: &[text_layout::Line],
 632        cx: &mut LayoutContext,
 633    ) -> Vec<(u32, ElementBox)> {
 634        snapshot
 635            .blocks_in_range(rows.clone())
 636            .map(|(start_row, block)| {
 637                let anchor_row = block
 638                    .position()
 639                    .to_point(&snapshot.buffer_snapshot)
 640                    .to_display_point(snapshot)
 641                    .row();
 642
 643                let anchor_x = text_x + if rows.contains(&anchor_row) {
 644                    line_layouts[(anchor_row - rows.start) as usize]
 645                        .x_for_index(block.column() as usize)
 646                } else {
 647                    layout_line(anchor_row, snapshot, style, cx.text_layout_cache)
 648                        .x_for_index(block.column() as usize)
 649                };
 650
 651                let mut element = block.render(&BlockContext { cx, anchor_x, line_number_x, });
 652                element.layout(
 653                    SizeConstraint {
 654                        min: Vector2F::zero(),
 655                        max: vec2f(width, block.height() as f32 * line_height),
 656                    },
 657                    cx,
 658                );
 659                (start_row, element)
 660            })
 661            .collect()
 662    }
 663}
 664
 665impl Element for EditorElement {
 666    type LayoutState = Option<LayoutState>;
 667    type PaintState = Option<PaintState>;
 668
 669    fn layout(
 670        &mut self,
 671        constraint: SizeConstraint,
 672        cx: &mut LayoutContext,
 673    ) -> (Vector2F, Self::LayoutState) {
 674        let mut size = constraint.max;
 675        if size.x().is_infinite() {
 676            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 677        }
 678
 679        let snapshot = self.snapshot(cx.app);
 680        let style = self.settings.style.clone();
 681        let line_height = style.text.line_height(cx.font_cache);
 682
 683        let gutter_padding;
 684        let gutter_width;
 685        if snapshot.mode == EditorMode::Full {
 686            gutter_padding = style.text.em_width(cx.font_cache);
 687            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 688        } else {
 689            gutter_padding = 0.0;
 690            gutter_width = 0.0
 691        };
 692
 693        let text_width = size.x() - gutter_width;
 694        let text_offset = vec2f(-style.text.descent(cx.font_cache), 0.);
 695        let em_width = style.text.em_width(cx.font_cache);
 696        let em_advance = style.text.em_advance(cx.font_cache);
 697        let overscroll = vec2f(em_width, 0.);
 698        let wrap_width = match self.settings.soft_wrap {
 699            SoftWrap::None => None,
 700            SoftWrap::EditorWidth => Some(text_width - text_offset.x() - overscroll.x() - em_width),
 701            SoftWrap::Column(column) => Some(column as f32 * em_advance),
 702        };
 703        let snapshot = self.update_view(cx.app, |view, cx| {
 704            if view.set_wrap_width(wrap_width, cx) {
 705                view.snapshot(cx)
 706            } else {
 707                snapshot
 708            }
 709        });
 710
 711        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
 712        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
 713            size.set_y(
 714                scroll_height
 715                    .min(constraint.max_along(Axis::Vertical))
 716                    .max(constraint.min_along(Axis::Vertical))
 717                    .min(line_height * max_lines as f32),
 718            )
 719        } else if size.y().is_infinite() {
 720            size.set_y(scroll_height);
 721        }
 722        let gutter_size = vec2f(gutter_width, size.y());
 723        let text_size = vec2f(text_width, size.y());
 724
 725        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
 726            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
 727            let snapshot = view.snapshot(cx);
 728            (autoscroll_horizontally, snapshot)
 729        });
 730
 731        let scroll_position = snapshot.scroll_position();
 732        let start_row = scroll_position.y() as u32;
 733        let scroll_top = scroll_position.y() * line_height;
 734        let end_row = ((scroll_top + size.y()) / line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 735
 736        let start_anchor = if start_row == 0 {
 737            Anchor::min()
 738        } else {
 739            snapshot
 740                .buffer_snapshot
 741                .anchor_before(DisplayPoint::new(start_row, 0).to_offset(&snapshot, Bias::Left))
 742        };
 743        let end_anchor = if end_row > snapshot.max_point().row() {
 744            Anchor::max()
 745        } else {
 746            snapshot
 747                .buffer_snapshot
 748                .anchor_before(DisplayPoint::new(end_row, 0).to_offset(&snapshot, Bias::Right))
 749        };
 750
 751        let mut selections = HashMap::default();
 752        let mut active_rows = BTreeMap::new();
 753        let mut highlighted_row = None;
 754        self.update_view(cx.app, |view, cx| {
 755            highlighted_row = view.highlighted_row();
 756            let display_map = view.display_map.update(cx, |map, cx| map.snapshot(cx));
 757
 758            let local_selections = view
 759                .local_selections_in_range(start_anchor.clone()..end_anchor.clone(), &display_map);
 760            for selection in &local_selections {
 761                let is_empty = selection.start == selection.end;
 762                let selection_start = snapshot.prev_line_boundary(selection.start).1;
 763                let selection_end = snapshot.next_line_boundary(selection.end).1;
 764                for row in cmp::max(selection_start.row(), start_row)
 765                    ..=cmp::min(selection_end.row(), end_row)
 766                {
 767                    let contains_non_empty_selection = active_rows.entry(row).or_insert(!is_empty);
 768                    *contains_non_empty_selection |= !is_empty;
 769                }
 770            }
 771            selections.insert(
 772                view.replica_id(cx),
 773                local_selections
 774                    .into_iter()
 775                    .map(|selection| crate::Selection {
 776                        id: selection.id,
 777                        goal: selection.goal,
 778                        reversed: selection.reversed,
 779                        start: selection.start.to_display_point(&display_map),
 780                        end: selection.end.to_display_point(&display_map),
 781                    })
 782                    .collect(),
 783            );
 784
 785            for (replica_id, selection) in display_map
 786                .buffer_snapshot
 787                .remote_selections_in_range(&(start_anchor..end_anchor))
 788            {
 789                selections
 790                    .entry(replica_id)
 791                    .or_insert(Vec::new())
 792                    .push(crate::Selection {
 793                        id: selection.id,
 794                        goal: selection.goal,
 795                        reversed: selection.reversed,
 796                        start: selection.start.to_display_point(&display_map),
 797                        end: selection.end.to_display_point(&display_map),
 798                    });
 799            }
 800        });
 801
 802        let line_number_layouts = self.layout_rows(start_row..end_row, &active_rows, &snapshot, cx);
 803
 804        let mut max_visible_line_width = 0.0;
 805        let line_layouts = self.layout_lines(start_row..end_row, &mut snapshot, cx);
 806        for line in &line_layouts {
 807            if line.width() > max_visible_line_width {
 808                max_visible_line_width = line.width();
 809            }
 810        }
 811
 812        let blocks = self.layout_blocks(
 813            start_row..end_row,
 814            &snapshot,
 815            size.x(),
 816            gutter_padding,
 817            gutter_width + text_offset.x(),
 818            line_height,
 819            &style,
 820            &line_layouts,
 821            cx,
 822        );
 823
 824        let mut layout = LayoutState {
 825            size,
 826            gutter_size,
 827            gutter_padding,
 828            text_size,
 829            overscroll,
 830            text_offset,
 831            snapshot,
 832            style: self.settings.style.clone(),
 833            active_rows,
 834            highlighted_row,
 835            line_layouts,
 836            line_number_layouts,
 837            blocks,
 838            line_height,
 839            em_width,
 840            em_advance,
 841            selections,
 842            max_visible_line_width,
 843        };
 844
 845        let scroll_max = layout.scroll_max(cx.font_cache, cx.text_layout_cache).x();
 846        let scroll_width = layout.scroll_width(cx.text_layout_cache);
 847        let max_glyph_width = style.text.em_width(&cx.font_cache);
 848        self.update_view(cx.app, |view, cx| {
 849            let clamped = view.clamp_scroll_left(scroll_max);
 850            let autoscrolled;
 851            if autoscroll_horizontally {
 852                autoscrolled = view.autoscroll_horizontally(
 853                    start_row,
 854                    layout.text_size.x(),
 855                    scroll_width,
 856                    max_glyph_width,
 857                    &layout.line_layouts,
 858                    cx,
 859                );
 860            } else {
 861                autoscrolled = false;
 862            }
 863
 864            if clamped || autoscrolled {
 865                layout.snapshot = view.snapshot(cx);
 866            }
 867        });
 868
 869        (size, Some(layout))
 870    }
 871
 872    fn paint(
 873        &mut self,
 874        bounds: RectF,
 875        visible_bounds: RectF,
 876        layout: &mut Self::LayoutState,
 877        cx: &mut PaintContext,
 878    ) -> Self::PaintState {
 879        if let Some(layout) = layout {
 880            cx.scene.push_layer(Some(bounds));
 881
 882            let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
 883            let text_bounds = RectF::new(
 884                bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
 885                layout.text_size,
 886            );
 887
 888            self.paint_background(gutter_bounds, text_bounds, layout, cx);
 889            if layout.gutter_size.x() > 0. {
 890                self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
 891            }
 892            self.paint_text(text_bounds, visible_bounds, layout, cx);
 893            self.paint_blocks(bounds, visible_bounds, layout, cx);
 894
 895            cx.scene.pop_layer();
 896
 897            Some(PaintState {
 898                bounds,
 899                gutter_bounds,
 900                text_bounds,
 901            })
 902        } else {
 903            None
 904        }
 905    }
 906
 907    fn dispatch_event(
 908        &mut self,
 909        event: &Event,
 910        _: RectF,
 911        layout: &mut Self::LayoutState,
 912        paint: &mut Self::PaintState,
 913        cx: &mut EventContext,
 914    ) -> bool {
 915        if let (Some(layout), Some(paint)) = (layout, paint) {
 916            match event {
 917                Event::LeftMouseDown {
 918                    position,
 919                    alt,
 920                    shift,
 921                    click_count,
 922                    ..
 923                } => self.mouse_down(*position, *alt, *shift, *click_count, layout, paint, cx),
 924                Event::LeftMouseUp { position } => self.mouse_up(*position, cx),
 925                Event::LeftMouseDragged { position } => {
 926                    self.mouse_dragged(*position, layout, paint, cx)
 927                }
 928                Event::ScrollWheel {
 929                    position,
 930                    delta,
 931                    precise,
 932                } => self.scroll(*position, *delta, *precise, layout, paint, cx),
 933                Event::KeyDown {
 934                    chars, keystroke, ..
 935                } => self.key_down(chars, keystroke, cx),
 936                _ => false,
 937            }
 938        } else {
 939            false
 940        }
 941    }
 942
 943    fn debug(
 944        &self,
 945        bounds: RectF,
 946        _: &Self::LayoutState,
 947        _: &Self::PaintState,
 948        _: &gpui::DebugContext,
 949    ) -> json::Value {
 950        json!({
 951            "type": "BufferElement",
 952            "bounds": bounds.to_json()
 953        })
 954    }
 955}
 956
 957pub struct LayoutState {
 958    size: Vector2F,
 959    gutter_size: Vector2F,
 960    gutter_padding: f32,
 961    text_size: Vector2F,
 962    style: EditorStyle,
 963    snapshot: EditorSnapshot,
 964    active_rows: BTreeMap<u32, bool>,
 965    highlighted_row: Option<u32>,
 966    line_layouts: Vec<text_layout::Line>,
 967    line_number_layouts: Vec<Option<text_layout::Line>>,
 968    blocks: Vec<(u32, ElementBox)>,
 969    line_height: f32,
 970    em_width: f32,
 971    em_advance: f32,
 972    selections: HashMap<ReplicaId, Vec<text::Selection<DisplayPoint>>>,
 973    overscroll: Vector2F,
 974    text_offset: Vector2F,
 975    max_visible_line_width: f32,
 976}
 977
 978impl LayoutState {
 979    fn scroll_width(&self, layout_cache: &TextLayoutCache) -> f32 {
 980        let row = self.snapshot.longest_row();
 981        let longest_line_width =
 982            layout_line(row, &self.snapshot, &self.style, layout_cache).width();
 983        longest_line_width.max(self.max_visible_line_width) + self.overscroll.x()
 984    }
 985
 986    fn scroll_max(&self, font_cache: &FontCache, layout_cache: &TextLayoutCache) -> Vector2F {
 987        let text_width = self.text_size.x();
 988        let scroll_width = self.scroll_width(layout_cache);
 989        let em_width = self.style.text.em_width(font_cache);
 990        let max_row = self.snapshot.max_point().row();
 991
 992        vec2f(
 993            ((scroll_width - text_width) / em_width).max(0.0),
 994            max_row.saturating_sub(1) as f32,
 995        )
 996    }
 997}
 998
 999fn layout_line(
1000    row: u32,
1001    snapshot: &EditorSnapshot,
1002    style: &EditorStyle,
1003    layout_cache: &TextLayoutCache,
1004) -> text_layout::Line {
1005    let mut line = snapshot.line(row);
1006
1007    if line.len() > MAX_LINE_LEN {
1008        let mut len = MAX_LINE_LEN;
1009        while !line.is_char_boundary(len) {
1010            len -= 1;
1011        }
1012        line.truncate(len);
1013    }
1014
1015    layout_cache.layout_str(
1016        &line,
1017        style.text.font_size,
1018        &[(
1019            snapshot.line_len(row) as usize,
1020            RunStyle {
1021                font_id: style.text.font_id,
1022                color: Color::black(),
1023                underline: None,
1024            },
1025        )],
1026    )
1027}
1028
1029pub struct PaintState {
1030    bounds: RectF,
1031    gutter_bounds: RectF,
1032    text_bounds: RectF,
1033}
1034
1035impl PaintState {
1036    fn point_for_position(
1037        &self,
1038        snapshot: &EditorSnapshot,
1039        layout: &LayoutState,
1040        position: Vector2F,
1041    ) -> (DisplayPoint, u32) {
1042        let scroll_position = snapshot.scroll_position();
1043        let position = position - self.text_bounds.origin();
1044        let y = position.y().max(0.0).min(layout.size.y());
1045        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
1046        let row = cmp::min(row, snapshot.max_point().row());
1047        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
1048        let x = position.x() + (scroll_position.x() * layout.em_width);
1049
1050        let column = if x >= 0.0 {
1051            line.index_for_x(x)
1052                .map(|ix| ix as u32)
1053                .unwrap_or_else(|| snapshot.line_len(row))
1054        } else {
1055            0
1056        };
1057        let overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
1058
1059        (DisplayPoint::new(row, column), overshoot)
1060    }
1061}
1062
1063struct Cursor {
1064    origin: Vector2F,
1065    line_height: f32,
1066    color: Color,
1067}
1068
1069impl Cursor {
1070    fn paint(&self, cx: &mut PaintContext) {
1071        cx.scene.push_quad(Quad {
1072            bounds: RectF::new(self.origin, vec2f(2.0, self.line_height)),
1073            background: Some(self.color),
1074            border: Border::new(0., Color::black()),
1075            corner_radius: 0.,
1076        });
1077    }
1078}
1079
1080#[derive(Debug)]
1081struct Selection {
1082    start_y: f32,
1083    line_height: f32,
1084    lines: Vec<SelectionLine>,
1085    color: Color,
1086}
1087
1088#[derive(Debug)]
1089struct SelectionLine {
1090    start_x: f32,
1091    end_x: f32,
1092}
1093
1094impl Selection {
1095    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1096        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1097            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1098            self.paint_lines(
1099                self.start_y + self.line_height,
1100                &self.lines[1..],
1101                bounds,
1102                scene,
1103            );
1104        } else {
1105            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1106        }
1107    }
1108
1109    fn paint_lines(&self, start_y: f32, lines: &[SelectionLine], bounds: RectF, scene: &mut Scene) {
1110        if lines.is_empty() {
1111            return;
1112        }
1113
1114        let mut path = PathBuilder::new();
1115        let corner_radius = 0.15 * self.line_height;
1116        let first_line = lines.first().unwrap();
1117        let last_line = lines.last().unwrap();
1118
1119        let first_top_left = vec2f(first_line.start_x, start_y);
1120        let first_top_right = vec2f(first_line.end_x, start_y);
1121
1122        let curve_height = vec2f(0., corner_radius);
1123        let curve_width = |start_x: f32, end_x: f32| {
1124            let max = (end_x - start_x) / 2.;
1125            let width = if max < corner_radius {
1126                max
1127            } else {
1128                corner_radius
1129            };
1130
1131            vec2f(width, 0.)
1132        };
1133
1134        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1135        path.reset(first_top_right - top_curve_width);
1136        path.curve_to(first_top_right + curve_height, first_top_right);
1137
1138        let mut iter = lines.iter().enumerate().peekable();
1139        while let Some((ix, line)) = iter.next() {
1140            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1141
1142            if let Some((_, next_line)) = iter.peek() {
1143                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1144
1145                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1146                    Ordering::Equal => {
1147                        path.line_to(bottom_right);
1148                    }
1149                    Ordering::Less => {
1150                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1151                        path.line_to(bottom_right - curve_height);
1152                        path.curve_to(bottom_right - curve_width, bottom_right);
1153                        path.line_to(next_top_right + curve_width);
1154                        path.curve_to(next_top_right + curve_height, next_top_right);
1155                    }
1156                    Ordering::Greater => {
1157                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1158                        path.line_to(bottom_right - curve_height);
1159                        path.curve_to(bottom_right + curve_width, bottom_right);
1160                        path.line_to(next_top_right - curve_width);
1161                        path.curve_to(next_top_right + curve_height, next_top_right);
1162                    }
1163                }
1164            } else {
1165                let curve_width = curve_width(line.start_x, line.end_x);
1166                path.line_to(bottom_right - curve_height);
1167                path.curve_to(bottom_right - curve_width, bottom_right);
1168
1169                let bottom_left = vec2f(line.start_x, bottom_right.y());
1170                path.line_to(bottom_left + curve_width);
1171                path.curve_to(bottom_left - curve_height, bottom_left);
1172            }
1173        }
1174
1175        if first_line.start_x > last_line.start_x {
1176            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1177            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1178            path.line_to(second_top_left + curve_height);
1179            path.curve_to(second_top_left + curve_width, second_top_left);
1180            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1181            path.line_to(first_bottom_left - curve_width);
1182            path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1183        }
1184
1185        path.line_to(first_top_left + curve_height);
1186        path.curve_to(first_top_left + top_curve_width, first_top_left);
1187        path.line_to(first_top_right - top_curve_width);
1188
1189        scene.push_path(path.build(self.color, Some(bounds)));
1190    }
1191}
1192
1193fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1194    delta.powf(1.5) / 100.0
1195}
1196
1197fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1198    delta.powf(1.2) / 300.0
1199}
1200
1201#[cfg(test)]
1202mod tests {
1203    use super::*;
1204    use crate::{Editor, EditorSettings, MultiBuffer};
1205    use std::sync::Arc;
1206    use util::test::sample_text;
1207
1208    #[gpui::test]
1209    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1210        let settings = EditorSettings::test(cx);
1211        let buffer = MultiBuffer::build_simple(&sample_text(6, 6, 'a'), cx);
1212        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1213            Editor::for_buffer(
1214                buffer,
1215                {
1216                    let settings = settings.clone();
1217                    Arc::new(move |_| settings.clone())
1218                },
1219                cx,
1220            )
1221        });
1222        let element = EditorElement::new(editor.downgrade(), settings);
1223
1224        let layouts = editor.update(cx, |editor, cx| {
1225            let snapshot = editor.snapshot(cx);
1226            let mut presenter = cx.build_presenter(window_id, 30.);
1227            let mut layout_cx = presenter.build_layout_context(false, cx);
1228            element.layout_rows(0..6, &Default::default(), &snapshot, &mut layout_cx)
1229        });
1230        assert_eq!(layouts.len(), 6);
1231    }
1232}