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_rows) = &layout.highlighted_rows {
 267                let origin = vec2f(
 268                    bounds.origin_x(),
 269                    bounds.origin_y() + (layout.line_height * highlighted_rows.start as f32)
 270                        - scroll_top,
 271                );
 272                let size = vec2f(
 273                    bounds.width(),
 274                    layout.line_height * highlighted_rows.len() as f32,
 275                );
 276                cx.scene.push_quad(Quad {
 277                    bounds: RectF::new(origin, size),
 278                    background: Some(style.highlighted_line_background),
 279                    border: Border::default(),
 280                    corner_radius: 0.,
 281                });
 282            }
 283        }
 284    }
 285
 286    fn paint_gutter(
 287        &mut self,
 288        bounds: RectF,
 289        visible_bounds: RectF,
 290        layout: &LayoutState,
 291        cx: &mut PaintContext,
 292    ) {
 293        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 294        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
 295            if let Some(line) = line {
 296                let line_origin = bounds.origin()
 297                    + vec2f(
 298                        bounds.width() - line.width() - layout.gutter_padding,
 299                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
 300                    );
 301                line.paint(line_origin, visible_bounds, layout.line_height, cx);
 302            }
 303        }
 304    }
 305
 306    fn paint_text(
 307        &mut self,
 308        bounds: RectF,
 309        visible_bounds: RectF,
 310        layout: &LayoutState,
 311        cx: &mut PaintContext,
 312    ) {
 313        let view = self.view(cx.app);
 314        let style = &self.settings.style;
 315        let local_replica_id = view.replica_id(cx);
 316        let scroll_position = layout.snapshot.scroll_position();
 317        let start_row = scroll_position.y() as u32;
 318        let scroll_top = scroll_position.y() * layout.line_height;
 319        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 320        let max_glyph_width = layout.em_width;
 321        let scroll_left = scroll_position.x() * max_glyph_width;
 322
 323        cx.scene.push_layer(Some(bounds));
 324
 325        // Draw selections
 326        let corner_radius = 2.5;
 327        let mut cursors = SmallVec::<[Cursor; 32]>::new();
 328
 329        let content_origin = bounds.origin() + layout.text_offset;
 330
 331        for (replica_id, selections) in &layout.selections {
 332            let style = style.replica_selection_style(*replica_id);
 333
 334            for selection in selections {
 335                if selection.start != selection.end {
 336                    let row_range = if selection.end.column() == 0 {
 337                        cmp::max(selection.start.row(), start_row)
 338                            ..cmp::min(selection.end.row(), end_row)
 339                    } else {
 340                        cmp::max(selection.start.row(), start_row)
 341                            ..cmp::min(selection.end.row() + 1, end_row)
 342                    };
 343
 344                    let selection = Selection {
 345                        color: style.selection,
 346                        line_height: layout.line_height,
 347                        start_y: content_origin.y() + row_range.start as f32 * layout.line_height
 348                            - scroll_top,
 349                        lines: row_range
 350                            .into_iter()
 351                            .map(|row| {
 352                                let line_layout = &layout.line_layouts[(row - start_row) as usize];
 353                                SelectionLine {
 354                                    start_x: if row == selection.start.row() {
 355                                        content_origin.x()
 356                                            + line_layout
 357                                                .x_for_index(selection.start.column() as usize)
 358                                            - scroll_left
 359                                    } else {
 360                                        content_origin.x() - scroll_left
 361                                    },
 362                                    end_x: if row == selection.end.row() {
 363                                        content_origin.x()
 364                                            + line_layout
 365                                                .x_for_index(selection.end.column() as usize)
 366                                            - scroll_left
 367                                    } else {
 368                                        content_origin.x()
 369                                            + line_layout.width()
 370                                            + corner_radius * 2.0
 371                                            - scroll_left
 372                                    },
 373                                }
 374                            })
 375                            .collect(),
 376                    };
 377
 378                    selection.paint(bounds, cx.scene);
 379                }
 380
 381                if view.show_local_cursors() || *replica_id != local_replica_id {
 382                    let cursor_position = selection.head();
 383                    if (start_row..end_row).contains(&cursor_position.row()) {
 384                        let cursor_row_layout =
 385                            &layout.line_layouts[(cursor_position.row() - start_row) as usize];
 386                        let x = cursor_row_layout.x_for_index(cursor_position.column() as usize)
 387                            - scroll_left;
 388                        let y = cursor_position.row() as f32 * layout.line_height - scroll_top;
 389                        cursors.push(Cursor {
 390                            color: style.cursor,
 391                            origin: content_origin + vec2f(x, y),
 392                            line_height: layout.line_height,
 393                        });
 394                    }
 395                }
 396            }
 397        }
 398
 399        if let Some(visible_text_bounds) = bounds.intersection(visible_bounds) {
 400            // Draw glyphs
 401            for (ix, line) in layout.line_layouts.iter().enumerate() {
 402                let row = start_row + ix as u32;
 403                line.paint(
 404                    content_origin
 405                        + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
 406                    visible_text_bounds,
 407                    layout.line_height,
 408                    cx,
 409                );
 410            }
 411        }
 412
 413        cx.scene.push_layer(Some(bounds));
 414        for cursor in cursors {
 415            cursor.paint(cx);
 416        }
 417        cx.scene.pop_layer();
 418
 419        cx.scene.pop_layer();
 420    }
 421
 422    fn paint_blocks(
 423        &mut self,
 424        bounds: RectF,
 425        visible_bounds: RectF,
 426        layout: &mut LayoutState,
 427        cx: &mut PaintContext,
 428    ) {
 429        let scroll_position = layout.snapshot.scroll_position();
 430        let scroll_left = scroll_position.x() * layout.em_width;
 431        let scroll_top = scroll_position.y() * layout.line_height;
 432
 433        for (row, element) in &mut layout.blocks {
 434            let origin = bounds.origin()
 435                + vec2f(-scroll_left, *row as f32 * layout.line_height - scroll_top);
 436            element.paint(origin, visible_bounds, cx);
 437        }
 438    }
 439
 440    fn max_line_number_width(&self, snapshot: &EditorSnapshot, cx: &LayoutContext) -> f32 {
 441        let digit_count = (snapshot.max_buffer_row() as f32).log10().floor() as usize + 1;
 442        let style = &self.settings.style;
 443
 444        cx.text_layout_cache
 445            .layout_str(
 446                "1".repeat(digit_count).as_str(),
 447                style.text.font_size,
 448                &[(
 449                    digit_count,
 450                    RunStyle {
 451                        font_id: style.text.font_id,
 452                        color: Color::black(),
 453                        underline: None,
 454                    },
 455                )],
 456            )
 457            .width()
 458    }
 459
 460    fn layout_rows(
 461        &self,
 462        rows: Range<u32>,
 463        active_rows: &BTreeMap<u32, bool>,
 464        snapshot: &EditorSnapshot,
 465        cx: &LayoutContext,
 466    ) -> Vec<Option<text_layout::Line>> {
 467        let style = &self.settings.style;
 468        let include_line_numbers = snapshot.mode == EditorMode::Full;
 469        let mut line_number_layouts = Vec::with_capacity(rows.len());
 470        let mut line_number = String::new();
 471        for (ix, row) in snapshot
 472            .buffer_rows(rows.start)
 473            .take((rows.end - rows.start) as usize)
 474            .enumerate()
 475        {
 476            let display_row = rows.start + ix as u32;
 477            let color = if active_rows.contains_key(&display_row) {
 478                style.line_number_active
 479            } else {
 480                style.line_number
 481            };
 482            if let Some(buffer_row) = row {
 483                if include_line_numbers {
 484                    line_number.clear();
 485                    write!(&mut line_number, "{}", buffer_row + 1).unwrap();
 486                    line_number_layouts.push(Some(cx.text_layout_cache.layout_str(
 487                        &line_number,
 488                        style.text.font_size,
 489                        &[(
 490                            line_number.len(),
 491                            RunStyle {
 492                                font_id: style.text.font_id,
 493                                color,
 494                                underline: None,
 495                            },
 496                        )],
 497                    )));
 498                }
 499            } else {
 500                line_number_layouts.push(None);
 501            }
 502        }
 503
 504        line_number_layouts
 505    }
 506
 507    fn layout_lines(
 508        &mut self,
 509        mut rows: Range<u32>,
 510        snapshot: &mut EditorSnapshot,
 511        cx: &LayoutContext,
 512    ) -> Vec<text_layout::Line> {
 513        rows.end = cmp::min(rows.end, snapshot.max_point().row() + 1);
 514        if rows.start >= rows.end {
 515            return Vec::new();
 516        }
 517
 518        // When the editor is empty and unfocused, then show the placeholder.
 519        if snapshot.is_empty() && !snapshot.is_focused() {
 520            let placeholder_style = self.settings.style.placeholder_text();
 521            let placeholder_text = snapshot.placeholder_text();
 522            let placeholder_lines = placeholder_text
 523                .as_ref()
 524                .map_or("", AsRef::as_ref)
 525                .split('\n')
 526                .skip(rows.start as usize)
 527                .take(rows.len());
 528            return placeholder_lines
 529                .map(|line| {
 530                    cx.text_layout_cache.layout_str(
 531                        line,
 532                        placeholder_style.font_size,
 533                        &[(
 534                            line.len(),
 535                            RunStyle {
 536                                font_id: placeholder_style.font_id,
 537                                color: placeholder_style.color,
 538                                underline: None,
 539                            },
 540                        )],
 541                    )
 542                })
 543                .collect();
 544        }
 545
 546        let style = &self.settings.style;
 547        let mut prev_font_properties = style.text.font_properties.clone();
 548        let mut prev_font_id = style.text.font_id;
 549
 550        let mut layouts = Vec::with_capacity(rows.len());
 551        let mut line = String::new();
 552        let mut styles = Vec::new();
 553        let mut row = rows.start;
 554        let mut line_exceeded_max_len = false;
 555        let chunks = snapshot.chunks(rows.clone(), Some(&style.syntax));
 556
 557        let newline_chunk = Chunk {
 558            text: "\n",
 559            ..Default::default()
 560        };
 561        'outer: for chunk in chunks.chain([newline_chunk]) {
 562            for (ix, mut line_chunk) in chunk.text.split('\n').enumerate() {
 563                if ix > 0 {
 564                    layouts.push(cx.text_layout_cache.layout_str(
 565                        &line,
 566                        style.text.font_size,
 567                        &styles,
 568                    ));
 569                    line.clear();
 570                    styles.clear();
 571                    row += 1;
 572                    line_exceeded_max_len = false;
 573                    if row == rows.end {
 574                        break 'outer;
 575                    }
 576                }
 577
 578                if !line_chunk.is_empty() && !line_exceeded_max_len {
 579                    let highlight_style =
 580                        chunk.highlight_style.unwrap_or(style.text.clone().into());
 581                    // Avoid a lookup if the font properties match the previous ones.
 582                    let font_id = if highlight_style.font_properties == prev_font_properties {
 583                        prev_font_id
 584                    } else {
 585                        cx.font_cache
 586                            .select_font(
 587                                style.text.font_family_id,
 588                                &highlight_style.font_properties,
 589                            )
 590                            .unwrap_or(style.text.font_id)
 591                    };
 592
 593                    if line.len() + line_chunk.len() > MAX_LINE_LEN {
 594                        let mut chunk_len = MAX_LINE_LEN - line.len();
 595                        while !line_chunk.is_char_boundary(chunk_len) {
 596                            chunk_len -= 1;
 597                        }
 598                        line_chunk = &line_chunk[..chunk_len];
 599                        line_exceeded_max_len = true;
 600                    }
 601
 602                    let underline = if let Some(severity) = chunk.diagnostic {
 603                        Some(super::diagnostic_style(severity, true, style).text)
 604                    } else {
 605                        highlight_style.underline
 606                    };
 607
 608                    line.push_str(line_chunk);
 609                    styles.push((
 610                        line_chunk.len(),
 611                        RunStyle {
 612                            font_id,
 613                            color: highlight_style.color,
 614                            underline,
 615                        },
 616                    ));
 617                    prev_font_id = font_id;
 618                    prev_font_properties = highlight_style.font_properties;
 619                }
 620            }
 621        }
 622
 623        layouts
 624    }
 625
 626    fn layout_blocks(
 627        &mut self,
 628        rows: Range<u32>,
 629        snapshot: &EditorSnapshot,
 630        width: f32,
 631        line_number_x: f32,
 632        text_x: f32,
 633        line_height: f32,
 634        style: &EditorStyle,
 635        line_layouts: &[text_layout::Line],
 636        cx: &mut LayoutContext,
 637    ) -> Vec<(u32, ElementBox)> {
 638        snapshot
 639            .blocks_in_range(rows.clone())
 640            .map(|(start_row, block)| {
 641                let anchor_row = block
 642                    .position()
 643                    .to_point(&snapshot.buffer_snapshot)
 644                    .to_display_point(snapshot)
 645                    .row();
 646
 647                let anchor_x = text_x
 648                    + if rows.contains(&anchor_row) {
 649                        line_layouts[(anchor_row - rows.start) as usize]
 650                            .x_for_index(block.column() as usize)
 651                    } else {
 652                        layout_line(anchor_row, snapshot, style, cx.text_layout_cache)
 653                            .x_for_index(block.column() as usize)
 654                    };
 655
 656                let mut element = block.render(&BlockContext {
 657                    cx,
 658                    anchor_x,
 659                    line_number_x,
 660                });
 661                element.layout(
 662                    SizeConstraint {
 663                        min: Vector2F::zero(),
 664                        max: vec2f(width, block.height() as f32 * line_height),
 665                    },
 666                    cx,
 667                );
 668                (start_row, element)
 669            })
 670            .collect()
 671    }
 672}
 673
 674impl Element for EditorElement {
 675    type LayoutState = Option<LayoutState>;
 676    type PaintState = Option<PaintState>;
 677
 678    fn layout(
 679        &mut self,
 680        constraint: SizeConstraint,
 681        cx: &mut LayoutContext,
 682    ) -> (Vector2F, Self::LayoutState) {
 683        let mut size = constraint.max;
 684        if size.x().is_infinite() {
 685            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 686        }
 687
 688        let snapshot = self.snapshot(cx.app);
 689        let style = self.settings.style.clone();
 690        let line_height = style.text.line_height(cx.font_cache);
 691
 692        let gutter_padding;
 693        let gutter_width;
 694        if snapshot.mode == EditorMode::Full {
 695            gutter_padding = style.text.em_width(cx.font_cache);
 696            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 697        } else {
 698            gutter_padding = 0.0;
 699            gutter_width = 0.0
 700        };
 701
 702        let text_width = size.x() - gutter_width;
 703        let text_offset = vec2f(-style.text.descent(cx.font_cache), 0.);
 704        let em_width = style.text.em_width(cx.font_cache);
 705        let em_advance = style.text.em_advance(cx.font_cache);
 706        let overscroll = vec2f(em_width, 0.);
 707        let wrap_width = match self.settings.soft_wrap {
 708            SoftWrap::None => None,
 709            SoftWrap::EditorWidth => Some(text_width - text_offset.x() - overscroll.x() - em_width),
 710            SoftWrap::Column(column) => Some(column as f32 * em_advance),
 711        };
 712        let snapshot = self.update_view(cx.app, |view, cx| {
 713            if view.set_wrap_width(wrap_width, cx) {
 714                view.snapshot(cx)
 715            } else {
 716                snapshot
 717            }
 718        });
 719
 720        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
 721        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
 722            size.set_y(
 723                scroll_height
 724                    .min(constraint.max_along(Axis::Vertical))
 725                    .max(constraint.min_along(Axis::Vertical))
 726                    .min(line_height * max_lines as f32),
 727            )
 728        } else if size.y().is_infinite() {
 729            size.set_y(scroll_height);
 730        }
 731        let gutter_size = vec2f(gutter_width, size.y());
 732        let text_size = vec2f(text_width, size.y());
 733
 734        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
 735            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
 736            let snapshot = view.snapshot(cx);
 737            (autoscroll_horizontally, snapshot)
 738        });
 739
 740        let scroll_position = snapshot.scroll_position();
 741        let start_row = scroll_position.y() as u32;
 742        let scroll_top = scroll_position.y() * line_height;
 743        let end_row = ((scroll_top + size.y()) / line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 744
 745        let start_anchor = if start_row == 0 {
 746            Anchor::min()
 747        } else {
 748            snapshot
 749                .buffer_snapshot
 750                .anchor_before(DisplayPoint::new(start_row, 0).to_offset(&snapshot, Bias::Left))
 751        };
 752        let end_anchor = if end_row > snapshot.max_point().row() {
 753            Anchor::max()
 754        } else {
 755            snapshot
 756                .buffer_snapshot
 757                .anchor_before(DisplayPoint::new(end_row, 0).to_offset(&snapshot, Bias::Right))
 758        };
 759
 760        let mut selections = HashMap::default();
 761        let mut active_rows = BTreeMap::new();
 762        let mut highlighted_rows = None;
 763        self.update_view(cx.app, |view, cx| {
 764            highlighted_rows = view.highlighted_rows();
 765            let display_map = view.display_map.update(cx, |map, cx| map.snapshot(cx));
 766
 767            let local_selections = view
 768                .local_selections_in_range(start_anchor.clone()..end_anchor.clone(), &display_map);
 769            for selection in &local_selections {
 770                let is_empty = selection.start == selection.end;
 771                let selection_start = snapshot.prev_line_boundary(selection.start).1;
 772                let selection_end = snapshot.next_line_boundary(selection.end).1;
 773                for row in cmp::max(selection_start.row(), start_row)
 774                    ..=cmp::min(selection_end.row(), end_row)
 775                {
 776                    let contains_non_empty_selection = active_rows.entry(row).or_insert(!is_empty);
 777                    *contains_non_empty_selection |= !is_empty;
 778                }
 779            }
 780            selections.insert(
 781                view.replica_id(cx),
 782                local_selections
 783                    .into_iter()
 784                    .map(|selection| crate::Selection {
 785                        id: selection.id,
 786                        goal: selection.goal,
 787                        reversed: selection.reversed,
 788                        start: selection.start.to_display_point(&display_map),
 789                        end: selection.end.to_display_point(&display_map),
 790                    })
 791                    .collect(),
 792            );
 793
 794            for (replica_id, selection) in display_map
 795                .buffer_snapshot
 796                .remote_selections_in_range(&(start_anchor..end_anchor))
 797            {
 798                selections
 799                    .entry(replica_id)
 800                    .or_insert(Vec::new())
 801                    .push(crate::Selection {
 802                        id: selection.id,
 803                        goal: selection.goal,
 804                        reversed: selection.reversed,
 805                        start: selection.start.to_display_point(&display_map),
 806                        end: selection.end.to_display_point(&display_map),
 807                    });
 808            }
 809        });
 810
 811        let line_number_layouts = self.layout_rows(start_row..end_row, &active_rows, &snapshot, cx);
 812
 813        let mut max_visible_line_width = 0.0;
 814        let line_layouts = self.layout_lines(start_row..end_row, &mut snapshot, cx);
 815        for line in &line_layouts {
 816            if line.width() > max_visible_line_width {
 817                max_visible_line_width = line.width();
 818            }
 819        }
 820
 821        let blocks = self.layout_blocks(
 822            start_row..end_row,
 823            &snapshot,
 824            size.x(),
 825            gutter_padding,
 826            gutter_width + text_offset.x(),
 827            line_height,
 828            &style,
 829            &line_layouts,
 830            cx,
 831        );
 832
 833        let mut layout = LayoutState {
 834            size,
 835            gutter_size,
 836            gutter_padding,
 837            text_size,
 838            overscroll,
 839            text_offset,
 840            snapshot,
 841            style: self.settings.style.clone(),
 842            active_rows,
 843            highlighted_rows,
 844            line_layouts,
 845            line_number_layouts,
 846            blocks,
 847            line_height,
 848            em_width,
 849            em_advance,
 850            selections,
 851            max_visible_line_width,
 852        };
 853
 854        let scroll_max = layout.scroll_max(cx.font_cache, cx.text_layout_cache).x();
 855        let scroll_width = layout.scroll_width(cx.text_layout_cache);
 856        let max_glyph_width = style.text.em_width(&cx.font_cache);
 857        self.update_view(cx.app, |view, cx| {
 858            let clamped = view.clamp_scroll_left(scroll_max);
 859            let autoscrolled;
 860            if autoscroll_horizontally {
 861                autoscrolled = view.autoscroll_horizontally(
 862                    start_row,
 863                    layout.text_size.x(),
 864                    scroll_width,
 865                    max_glyph_width,
 866                    &layout.line_layouts,
 867                    cx,
 868                );
 869            } else {
 870                autoscrolled = false;
 871            }
 872
 873            if clamped || autoscrolled {
 874                layout.snapshot = view.snapshot(cx);
 875            }
 876        });
 877
 878        (size, Some(layout))
 879    }
 880
 881    fn paint(
 882        &mut self,
 883        bounds: RectF,
 884        visible_bounds: RectF,
 885        layout: &mut Self::LayoutState,
 886        cx: &mut PaintContext,
 887    ) -> Self::PaintState {
 888        if let Some(layout) = layout {
 889            cx.scene.push_layer(Some(bounds));
 890
 891            let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
 892            let text_bounds = RectF::new(
 893                bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
 894                layout.text_size,
 895            );
 896
 897            self.paint_background(gutter_bounds, text_bounds, layout, cx);
 898            if layout.gutter_size.x() > 0. {
 899                self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
 900            }
 901            self.paint_text(text_bounds, visible_bounds, layout, cx);
 902            self.paint_blocks(bounds, visible_bounds, layout, cx);
 903
 904            cx.scene.pop_layer();
 905
 906            Some(PaintState {
 907                bounds,
 908                gutter_bounds,
 909                text_bounds,
 910            })
 911        } else {
 912            None
 913        }
 914    }
 915
 916    fn dispatch_event(
 917        &mut self,
 918        event: &Event,
 919        _: RectF,
 920        layout: &mut Self::LayoutState,
 921        paint: &mut Self::PaintState,
 922        cx: &mut EventContext,
 923    ) -> bool {
 924        if let (Some(layout), Some(paint)) = (layout, paint) {
 925            match event {
 926                Event::LeftMouseDown {
 927                    position,
 928                    alt,
 929                    shift,
 930                    click_count,
 931                    ..
 932                } => self.mouse_down(*position, *alt, *shift, *click_count, layout, paint, cx),
 933                Event::LeftMouseUp { position } => self.mouse_up(*position, cx),
 934                Event::LeftMouseDragged { position } => {
 935                    self.mouse_dragged(*position, layout, paint, cx)
 936                }
 937                Event::ScrollWheel {
 938                    position,
 939                    delta,
 940                    precise,
 941                } => self.scroll(*position, *delta, *precise, layout, paint, cx),
 942                Event::KeyDown {
 943                    chars, keystroke, ..
 944                } => self.key_down(chars, keystroke, cx),
 945                _ => false,
 946            }
 947        } else {
 948            false
 949        }
 950    }
 951
 952    fn debug(
 953        &self,
 954        bounds: RectF,
 955        _: &Self::LayoutState,
 956        _: &Self::PaintState,
 957        _: &gpui::DebugContext,
 958    ) -> json::Value {
 959        json!({
 960            "type": "BufferElement",
 961            "bounds": bounds.to_json()
 962        })
 963    }
 964}
 965
 966pub struct LayoutState {
 967    size: Vector2F,
 968    gutter_size: Vector2F,
 969    gutter_padding: f32,
 970    text_size: Vector2F,
 971    style: EditorStyle,
 972    snapshot: EditorSnapshot,
 973    active_rows: BTreeMap<u32, bool>,
 974    highlighted_rows: Option<Range<u32>>,
 975    line_layouts: Vec<text_layout::Line>,
 976    line_number_layouts: Vec<Option<text_layout::Line>>,
 977    blocks: Vec<(u32, ElementBox)>,
 978    line_height: f32,
 979    em_width: f32,
 980    em_advance: f32,
 981    selections: HashMap<ReplicaId, Vec<text::Selection<DisplayPoint>>>,
 982    overscroll: Vector2F,
 983    text_offset: Vector2F,
 984    max_visible_line_width: f32,
 985}
 986
 987impl LayoutState {
 988    fn scroll_width(&self, layout_cache: &TextLayoutCache) -> f32 {
 989        let row = self.snapshot.longest_row();
 990        let longest_line_width =
 991            layout_line(row, &self.snapshot, &self.style, layout_cache).width();
 992        longest_line_width.max(self.max_visible_line_width) + self.overscroll.x()
 993    }
 994
 995    fn scroll_max(&self, font_cache: &FontCache, layout_cache: &TextLayoutCache) -> Vector2F {
 996        let text_width = self.text_size.x();
 997        let scroll_width = self.scroll_width(layout_cache);
 998        let em_width = self.style.text.em_width(font_cache);
 999        let max_row = self.snapshot.max_point().row();
1000
1001        vec2f(
1002            ((scroll_width - text_width) / em_width).max(0.0),
1003            max_row.saturating_sub(1) as f32,
1004        )
1005    }
1006}
1007
1008fn layout_line(
1009    row: u32,
1010    snapshot: &EditorSnapshot,
1011    style: &EditorStyle,
1012    layout_cache: &TextLayoutCache,
1013) -> text_layout::Line {
1014    let mut line = snapshot.line(row);
1015
1016    if line.len() > MAX_LINE_LEN {
1017        let mut len = MAX_LINE_LEN;
1018        while !line.is_char_boundary(len) {
1019            len -= 1;
1020        }
1021        line.truncate(len);
1022    }
1023
1024    layout_cache.layout_str(
1025        &line,
1026        style.text.font_size,
1027        &[(
1028            snapshot.line_len(row) as usize,
1029            RunStyle {
1030                font_id: style.text.font_id,
1031                color: Color::black(),
1032                underline: None,
1033            },
1034        )],
1035    )
1036}
1037
1038pub struct PaintState {
1039    bounds: RectF,
1040    gutter_bounds: RectF,
1041    text_bounds: RectF,
1042}
1043
1044impl PaintState {
1045    fn point_for_position(
1046        &self,
1047        snapshot: &EditorSnapshot,
1048        layout: &LayoutState,
1049        position: Vector2F,
1050    ) -> (DisplayPoint, u32) {
1051        let scroll_position = snapshot.scroll_position();
1052        let position = position - self.text_bounds.origin();
1053        let y = position.y().max(0.0).min(layout.size.y());
1054        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
1055        let row = cmp::min(row, snapshot.max_point().row());
1056        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
1057        let x = position.x() + (scroll_position.x() * layout.em_width);
1058
1059        let column = if x >= 0.0 {
1060            line.index_for_x(x)
1061                .map(|ix| ix as u32)
1062                .unwrap_or_else(|| snapshot.line_len(row))
1063        } else {
1064            0
1065        };
1066        let overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
1067
1068        (DisplayPoint::new(row, column), overshoot)
1069    }
1070}
1071
1072struct Cursor {
1073    origin: Vector2F,
1074    line_height: f32,
1075    color: Color,
1076}
1077
1078impl Cursor {
1079    fn paint(&self, cx: &mut PaintContext) {
1080        cx.scene.push_quad(Quad {
1081            bounds: RectF::new(self.origin, vec2f(2.0, self.line_height)),
1082            background: Some(self.color),
1083            border: Border::new(0., Color::black()),
1084            corner_radius: 0.,
1085        });
1086    }
1087}
1088
1089#[derive(Debug)]
1090struct Selection {
1091    start_y: f32,
1092    line_height: f32,
1093    lines: Vec<SelectionLine>,
1094    color: Color,
1095}
1096
1097#[derive(Debug)]
1098struct SelectionLine {
1099    start_x: f32,
1100    end_x: f32,
1101}
1102
1103impl Selection {
1104    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1105        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1106            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1107            self.paint_lines(
1108                self.start_y + self.line_height,
1109                &self.lines[1..],
1110                bounds,
1111                scene,
1112            );
1113        } else {
1114            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1115        }
1116    }
1117
1118    fn paint_lines(&self, start_y: f32, lines: &[SelectionLine], bounds: RectF, scene: &mut Scene) {
1119        if lines.is_empty() {
1120            return;
1121        }
1122
1123        let mut path = PathBuilder::new();
1124        let corner_radius = 0.15 * self.line_height;
1125        let first_line = lines.first().unwrap();
1126        let last_line = lines.last().unwrap();
1127
1128        let first_top_left = vec2f(first_line.start_x, start_y);
1129        let first_top_right = vec2f(first_line.end_x, start_y);
1130
1131        let curve_height = vec2f(0., corner_radius);
1132        let curve_width = |start_x: f32, end_x: f32| {
1133            let max = (end_x - start_x) / 2.;
1134            let width = if max < corner_radius {
1135                max
1136            } else {
1137                corner_radius
1138            };
1139
1140            vec2f(width, 0.)
1141        };
1142
1143        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1144        path.reset(first_top_right - top_curve_width);
1145        path.curve_to(first_top_right + curve_height, first_top_right);
1146
1147        let mut iter = lines.iter().enumerate().peekable();
1148        while let Some((ix, line)) = iter.next() {
1149            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1150
1151            if let Some((_, next_line)) = iter.peek() {
1152                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1153
1154                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1155                    Ordering::Equal => {
1156                        path.line_to(bottom_right);
1157                    }
1158                    Ordering::Less => {
1159                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1160                        path.line_to(bottom_right - curve_height);
1161                        path.curve_to(bottom_right - curve_width, bottom_right);
1162                        path.line_to(next_top_right + curve_width);
1163                        path.curve_to(next_top_right + curve_height, next_top_right);
1164                    }
1165                    Ordering::Greater => {
1166                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1167                        path.line_to(bottom_right - curve_height);
1168                        path.curve_to(bottom_right + curve_width, bottom_right);
1169                        path.line_to(next_top_right - curve_width);
1170                        path.curve_to(next_top_right + curve_height, next_top_right);
1171                    }
1172                }
1173            } else {
1174                let curve_width = curve_width(line.start_x, line.end_x);
1175                path.line_to(bottom_right - curve_height);
1176                path.curve_to(bottom_right - curve_width, bottom_right);
1177
1178                let bottom_left = vec2f(line.start_x, bottom_right.y());
1179                path.line_to(bottom_left + curve_width);
1180                path.curve_to(bottom_left - curve_height, bottom_left);
1181            }
1182        }
1183
1184        if first_line.start_x > last_line.start_x {
1185            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1186            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1187            path.line_to(second_top_left + curve_height);
1188            path.curve_to(second_top_left + curve_width, second_top_left);
1189            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1190            path.line_to(first_bottom_left - curve_width);
1191            path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1192        }
1193
1194        path.line_to(first_top_left + curve_height);
1195        path.curve_to(first_top_left + top_curve_width, first_top_left);
1196        path.line_to(first_top_right - top_curve_width);
1197
1198        scene.push_path(path.build(self.color, Some(bounds)));
1199    }
1200}
1201
1202fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1203    delta.powf(1.5) / 100.0
1204}
1205
1206fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1207    delta.powf(1.2) / 300.0
1208}
1209
1210#[cfg(test)]
1211mod tests {
1212    use super::*;
1213    use crate::{Editor, EditorSettings, MultiBuffer};
1214    use std::sync::Arc;
1215    use util::test::sample_text;
1216
1217    #[gpui::test]
1218    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1219        let settings = EditorSettings::test(cx);
1220        let buffer = MultiBuffer::build_simple(&sample_text(6, 6, 'a'), cx);
1221        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1222            Editor::for_buffer(
1223                buffer,
1224                {
1225                    let settings = settings.clone();
1226                    Arc::new(move |_| settings.clone())
1227                },
1228                cx,
1229            )
1230        });
1231        let element = EditorElement::new(editor.downgrade(), settings);
1232
1233        let layouts = editor.update(cx, |editor, cx| {
1234            let snapshot = editor.snapshot(cx);
1235            let mut presenter = cx.build_presenter(window_id, 30.);
1236            let mut layout_cx = presenter.build_layout_context(false, cx);
1237            element.layout_rows(0..6, &Default::default(), &snapshot, &mut layout_cx)
1238        });
1239        assert_eq!(layouts.len(), 6);
1240    }
1241}