element.rs

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