element.rs

   1use crate::display_map::{BlockContext, ToDisplayPoint};
   2
   3use super::{
   4    DisplayPoint, Editor, EditorMode, EditorSettings, EditorSnapshot, EditorStyle, Input, Scroll,
   5    Select, SelectPhase, SoftWrap, MAX_LINE_LEN,
   6};
   7use crate::ToPoint;
   8use clock::ReplicaId;
   9use gpui::{
  10    color::Color,
  11    geometry::{
  12        rect::RectF,
  13        vector::{vec2f, Vector2F},
  14        PathBuilder,
  15    },
  16    json::{self, ToJson},
  17    keymap::Keystroke,
  18    text_layout::{self, RunStyle, TextLayoutCache},
  19    AppContext, Axis, Border, Element, ElementBox, Event, EventContext, FontCache, LayoutContext,
  20    MutableAppContext, PaintContext, Quad, Scene, SizeConstraint, ViewContext, WeakViewHandle,
  21};
  22use json::json;
  23use language::Chunk;
  24use smallvec::SmallVec;
  25use std::{
  26    cmp::{self, Ordering},
  27    collections::{BTreeMap, HashMap},
  28    fmt::Write,
  29    ops::Range,
  30};
  31
  32pub struct EditorElement {
  33    view: WeakViewHandle<Editor>,
  34    settings: EditorSettings,
  35}
  36
  37impl EditorElement {
  38    pub fn new(view: WeakViewHandle<Editor>, settings: EditorSettings) -> Self {
  39        Self { view, settings }
  40    }
  41
  42    fn view<'a>(&self, cx: &'a AppContext) -> &'a Editor {
  43        self.view.upgrade(cx).unwrap().read(cx)
  44    }
  45
  46    fn update_view<F, T>(&self, cx: &mut MutableAppContext, f: F) -> T
  47    where
  48        F: FnOnce(&mut Editor, &mut ViewContext<Editor>) -> T,
  49    {
  50        self.view.upgrade(cx).unwrap().update(cx, f)
  51    }
  52
  53    fn snapshot(&self, cx: &mut MutableAppContext) -> EditorSnapshot {
  54        self.update_view(cx, |view, cx| view.snapshot(cx))
  55    }
  56
  57    fn mouse_down(
  58        &self,
  59        position: Vector2F,
  60        alt: bool,
  61        shift: bool,
  62        mut click_count: usize,
  63        layout: &mut LayoutState,
  64        paint: &mut PaintState,
  65        cx: &mut EventContext,
  66    ) -> bool {
  67        if paint.gutter_bounds.contains_point(position) {
  68            click_count = 3; // Simulate triple-click when clicking the gutter to select lines
  69        } else if !paint.text_bounds.contains_point(position) {
  70            return false;
  71        }
  72
  73        let snapshot = self.snapshot(cx.app);
  74        let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
  75
  76        if shift && alt {
  77            cx.dispatch_action(Select(SelectPhase::BeginColumnar {
  78                position,
  79                overshoot,
  80            }));
  81        } else if shift {
  82            cx.dispatch_action(Select(SelectPhase::Extend {
  83                position,
  84                click_count,
  85            }));
  86        } else {
  87            cx.dispatch_action(Select(SelectPhase::Begin {
  88                position,
  89                add: alt,
  90                click_count,
  91            }));
  92        }
  93
  94        true
  95    }
  96
  97    fn mouse_up(&self, _position: Vector2F, cx: &mut EventContext) -> bool {
  98        if self.view(cx.app.as_ref()).is_selecting() {
  99            cx.dispatch_action(Select(SelectPhase::End));
 100            true
 101        } else {
 102            false
 103        }
 104    }
 105
 106    fn mouse_dragged(
 107        &self,
 108        position: Vector2F,
 109        layout: &mut LayoutState,
 110        paint: &mut PaintState,
 111        cx: &mut EventContext,
 112    ) -> bool {
 113        let view = self.view(cx.app.as_ref());
 114
 115        if view.is_selecting() {
 116            let rect = paint.text_bounds;
 117            let mut scroll_delta = Vector2F::zero();
 118
 119            let vertical_margin = layout.line_height.min(rect.height() / 3.0);
 120            let top = rect.origin_y() + vertical_margin;
 121            let bottom = rect.lower_left().y() - vertical_margin;
 122            if position.y() < top {
 123                scroll_delta.set_y(-scale_vertical_mouse_autoscroll_delta(top - position.y()))
 124            }
 125            if position.y() > bottom {
 126                scroll_delta.set_y(scale_vertical_mouse_autoscroll_delta(position.y() - bottom))
 127            }
 128
 129            let horizontal_margin = layout.line_height.min(rect.width() / 3.0);
 130            let left = rect.origin_x() + horizontal_margin;
 131            let right = rect.upper_right().x() - horizontal_margin;
 132            if position.x() < left {
 133                scroll_delta.set_x(-scale_horizontal_mouse_autoscroll_delta(
 134                    left - position.x(),
 135                ))
 136            }
 137            if position.x() > right {
 138                scroll_delta.set_x(scale_horizontal_mouse_autoscroll_delta(
 139                    position.x() - right,
 140                ))
 141            }
 142
 143            let font_cache = cx.font_cache.clone();
 144            let text_layout_cache = cx.text_layout_cache.clone();
 145            let snapshot = self.snapshot(cx.app);
 146            let (position, overshoot) = paint.point_for_position(&snapshot, layout, position);
 147
 148            cx.dispatch_action(Select(SelectPhase::Update {
 149                position,
 150                overshoot,
 151                scroll_position: (snapshot.scroll_position() + scroll_delta).clamp(
 152                    Vector2F::zero(),
 153                    layout.scroll_max(&font_cache, &text_layout_cache),
 154                ),
 155            }));
 156            true
 157        } else {
 158            false
 159        }
 160    }
 161
 162    fn key_down(&self, chars: &str, keystroke: &Keystroke, cx: &mut EventContext) -> bool {
 163        let view = self.view.upgrade(cx.app).unwrap();
 164
 165        if view.is_focused(cx.app) {
 166            if chars.is_empty() {
 167                false
 168            } else {
 169                if chars.chars().any(|c| c.is_control()) || keystroke.cmd || keystroke.ctrl {
 170                    false
 171                } else {
 172                    cx.dispatch_action(Input(chars.to_string()));
 173                    true
 174                }
 175            }
 176        } else {
 177            false
 178        }
 179    }
 180
 181    fn scroll(
 182        &self,
 183        position: Vector2F,
 184        mut delta: Vector2F,
 185        precise: bool,
 186        layout: &mut LayoutState,
 187        paint: &mut PaintState,
 188        cx: &mut EventContext,
 189    ) -> bool {
 190        if !paint.bounds.contains_point(position) {
 191            return false;
 192        }
 193
 194        let snapshot = self.snapshot(cx.app);
 195        let font_cache = &cx.font_cache;
 196        let layout_cache = &cx.text_layout_cache;
 197        let max_glyph_width = layout.em_width;
 198        if !precise {
 199            delta *= vec2f(max_glyph_width, layout.line_height);
 200        }
 201
 202        let scroll_position = snapshot.scroll_position();
 203        let x = (scroll_position.x() * max_glyph_width - delta.x()) / max_glyph_width;
 204        let y = (scroll_position.y() * layout.line_height - delta.y()) / layout.line_height;
 205        let scroll_position = vec2f(x, y).clamp(
 206            Vector2F::zero(),
 207            layout.scroll_max(font_cache, layout_cache),
 208        );
 209
 210        cx.dispatch_action(Scroll(scroll_position));
 211
 212        true
 213    }
 214
 215    fn paint_background(
 216        &self,
 217        gutter_bounds: RectF,
 218        text_bounds: RectF,
 219        layout: &LayoutState,
 220        cx: &mut PaintContext,
 221    ) {
 222        let bounds = gutter_bounds.union_rect(text_bounds);
 223        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 224        let editor = self.view(cx.app);
 225        let style = &self.settings.style;
 226        cx.scene.push_quad(Quad {
 227            bounds: gutter_bounds,
 228            background: Some(style.gutter_background),
 229            border: Border::new(0., Color::transparent_black()),
 230            corner_radius: 0.,
 231        });
 232        cx.scene.push_quad(Quad {
 233            bounds: text_bounds,
 234            background: Some(style.background),
 235            border: Border::new(0., Color::transparent_black()),
 236            corner_radius: 0.,
 237        });
 238
 239        if let EditorMode::Full = editor.mode {
 240            let mut active_rows = layout.active_rows.iter().peekable();
 241            while let Some((start_row, contains_non_empty_selection)) = active_rows.next() {
 242                let mut end_row = *start_row;
 243                while active_rows.peek().map_or(false, |r| {
 244                    *r.0 == end_row + 1 && r.1 == contains_non_empty_selection
 245                }) {
 246                    active_rows.next().unwrap();
 247                    end_row += 1;
 248                }
 249
 250                if !contains_non_empty_selection {
 251                    let origin = vec2f(
 252                        bounds.origin_x(),
 253                        bounds.origin_y() + (layout.line_height * *start_row as f32) - scroll_top,
 254                    );
 255                    let size = vec2f(
 256                        bounds.width(),
 257                        layout.line_height * (end_row - start_row + 1) as f32,
 258                    );
 259                    cx.scene.push_quad(Quad {
 260                        bounds: RectF::new(origin, size),
 261                        background: Some(style.active_line_background),
 262                        border: Border::default(),
 263                        corner_radius: 0.,
 264                    });
 265                }
 266            }
 267
 268            if let Some(highlighted_row) = layout.highlighted_row {
 269                let origin = vec2f(
 270                    bounds.origin_x(),
 271                    bounds.origin_y() + (layout.line_height * highlighted_row as f32) - scroll_top,
 272                );
 273                let size = vec2f(bounds.width(), layout.line_height);
 274                cx.scene.push_quad(Quad {
 275                    bounds: RectF::new(origin, size),
 276                    background: Some(style.highlighted_line_background),
 277                    border: Border::default(),
 278                    corner_radius: 0.,
 279                });
 280            }
 281        }
 282    }
 283
 284    fn paint_gutter(
 285        &mut self,
 286        bounds: RectF,
 287        visible_bounds: RectF,
 288        layout: &LayoutState,
 289        cx: &mut PaintContext,
 290    ) {
 291        let scroll_top = layout.snapshot.scroll_position().y() * layout.line_height;
 292        for (ix, line) in layout.line_number_layouts.iter().enumerate() {
 293            if let Some(line) = line {
 294                let line_origin = bounds.origin()
 295                    + vec2f(
 296                        bounds.width() - line.width() - layout.gutter_padding,
 297                        ix as f32 * layout.line_height - (scroll_top % layout.line_height),
 298                    );
 299                line.paint(line_origin, visible_bounds, layout.line_height, cx);
 300            }
 301        }
 302    }
 303
 304    fn paint_text(
 305        &mut self,
 306        bounds: RectF,
 307        visible_bounds: RectF,
 308        layout: &LayoutState,
 309        cx: &mut PaintContext,
 310    ) {
 311        let view = self.view(cx.app);
 312        let style = &self.settings.style;
 313        let local_replica_id = view.replica_id(cx);
 314        let scroll_position = layout.snapshot.scroll_position();
 315        let start_row = scroll_position.y() as u32;
 316        let scroll_top = scroll_position.y() * layout.line_height;
 317        let end_row = ((scroll_top + bounds.height()) / layout.line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 318        let max_glyph_width = layout.em_width;
 319        let scroll_left = scroll_position.x() * max_glyph_width;
 320
 321        cx.scene.push_layer(Some(bounds));
 322
 323        // Draw selections
 324        let corner_radius = 2.5;
 325        let mut cursors = SmallVec::<[Cursor; 32]>::new();
 326
 327        let content_origin = bounds.origin() + layout.text_offset;
 328
 329        for (replica_id, selections) in &layout.selections {
 330            let style = style.replica_selection_style(*replica_id);
 331
 332            for selection in selections {
 333                if selection.start != selection.end {
 334                    let row_range = if selection.end.column() == 0 {
 335                        cmp::max(selection.start.row(), start_row)
 336                            ..cmp::min(selection.end.row(), end_row)
 337                    } else {
 338                        cmp::max(selection.start.row(), start_row)
 339                            ..cmp::min(selection.end.row() + 1, end_row)
 340                    };
 341
 342                    let selection = Selection {
 343                        color: style.selection,
 344                        line_height: layout.line_height,
 345                        start_y: content_origin.y() + row_range.start as f32 * layout.line_height
 346                            - scroll_top,
 347                        lines: row_range
 348                            .into_iter()
 349                            .map(|row| {
 350                                let line_layout = &layout.line_layouts[(row - start_row) as usize];
 351                                SelectionLine {
 352                                    start_x: if row == selection.start.row() {
 353                                        content_origin.x()
 354                                            + line_layout
 355                                                .x_for_index(selection.start.column() as usize)
 356                                            - scroll_left
 357                                    } else {
 358                                        content_origin.x() - scroll_left
 359                                    },
 360                                    end_x: if row == selection.end.row() {
 361                                        content_origin.x()
 362                                            + line_layout
 363                                                .x_for_index(selection.end.column() as usize)
 364                                            - scroll_left
 365                                    } else {
 366                                        content_origin.x()
 367                                            + line_layout.width()
 368                                            + corner_radius * 2.0
 369                                            - scroll_left
 370                                    },
 371                                }
 372                            })
 373                            .collect(),
 374                    };
 375
 376                    selection.paint(bounds, cx.scene);
 377                }
 378
 379                if view.show_local_cursors() || *replica_id != local_replica_id {
 380                    let cursor_position = selection.head();
 381                    if (start_row..end_row).contains(&cursor_position.row()) {
 382                        let cursor_row_layout =
 383                            &layout.line_layouts[(cursor_position.row() - start_row) as usize];
 384                        let x = cursor_row_layout.x_for_index(cursor_position.column() as usize)
 385                            - scroll_left;
 386                        let y = cursor_position.row() as f32 * layout.line_height - scroll_top;
 387                        cursors.push(Cursor {
 388                            color: style.cursor,
 389                            origin: content_origin + vec2f(x, y),
 390                            line_height: layout.line_height,
 391                        });
 392                    }
 393                }
 394            }
 395        }
 396
 397        if let Some(visible_text_bounds) = bounds.intersection(visible_bounds) {
 398            // Draw glyphs
 399            for (ix, line) in layout.line_layouts.iter().enumerate() {
 400                let row = start_row + ix as u32;
 401                line.paint(
 402                    content_origin
 403                        + vec2f(-scroll_left, row as f32 * layout.line_height - scroll_top),
 404                    visible_text_bounds,
 405                    layout.line_height,
 406                    cx,
 407                );
 408            }
 409        }
 410
 411        cx.scene.push_layer(Some(bounds));
 412        for cursor in cursors {
 413            cursor.paint(cx);
 414        }
 415        cx.scene.pop_layer();
 416
 417        cx.scene.pop_layer();
 418    }
 419
 420    fn paint_blocks(
 421        &mut self,
 422        text_bounds: RectF,
 423        visible_bounds: RectF,
 424        layout: &mut LayoutState,
 425        cx: &mut PaintContext,
 426    ) {
 427        let scroll_position = layout.snapshot.scroll_position();
 428        let scroll_left = scroll_position.x() * layout.em_width;
 429        let scroll_top = scroll_position.y() * layout.line_height;
 430
 431        for (row, element) in &mut layout.blocks {
 432            let origin = text_bounds.origin()
 433                + vec2f(-scroll_left, *row as f32 * layout.line_height - scroll_top);
 434            element.paint(origin, visible_bounds, cx);
 435        }
 436    }
 437
 438    fn max_line_number_width(&self, snapshot: &EditorSnapshot, cx: &LayoutContext) -> f32 {
 439        let digit_count = (snapshot.buffer_row_count() as f32).log10().floor() as usize + 1;
 440        let style = &self.settings.style;
 441
 442        cx.text_layout_cache
 443            .layout_str(
 444                "1".repeat(digit_count).as_str(),
 445                style.text.font_size,
 446                &[(
 447                    digit_count,
 448                    RunStyle {
 449                        font_id: style.text.font_id,
 450                        color: Color::black(),
 451                        underline: None,
 452                    },
 453                )],
 454            )
 455            .width()
 456    }
 457
 458    fn layout_rows(
 459        &self,
 460        rows: Range<u32>,
 461        active_rows: &BTreeMap<u32, bool>,
 462        snapshot: &EditorSnapshot,
 463        cx: &LayoutContext,
 464    ) -> Vec<Option<text_layout::Line>> {
 465        let style = &self.settings.style;
 466        let include_line_numbers = snapshot.mode == EditorMode::Full;
 467        let mut line_number_layouts = Vec::with_capacity(rows.len());
 468        let mut line_number = String::new();
 469        for (ix, row) in snapshot
 470            .buffer_rows(rows.start)
 471            .take((rows.end - rows.start) as usize)
 472            .enumerate()
 473        {
 474            let display_row = rows.start + ix as u32;
 475            let color = if active_rows.contains_key(&display_row) {
 476                style.line_number_active
 477            } else {
 478                style.line_number
 479            };
 480            if let Some(buffer_row) = row {
 481                if include_line_numbers {
 482                    line_number.clear();
 483                    write!(&mut line_number, "{}", buffer_row + 1).unwrap();
 484                    line_number_layouts.push(Some(cx.text_layout_cache.layout_str(
 485                        &line_number,
 486                        style.text.font_size,
 487                        &[(
 488                            line_number.len(),
 489                            RunStyle {
 490                                font_id: style.text.font_id,
 491                                color,
 492                                underline: None,
 493                            },
 494                        )],
 495                    )));
 496                }
 497            } else {
 498                line_number_layouts.push(None);
 499            }
 500        }
 501
 502        line_number_layouts
 503    }
 504
 505    fn layout_lines(
 506        &mut self,
 507        mut rows: Range<u32>,
 508        snapshot: &mut EditorSnapshot,
 509        cx: &LayoutContext,
 510    ) -> Vec<text_layout::Line> {
 511        rows.end = cmp::min(rows.end, snapshot.max_point().row() + 1);
 512        if rows.start >= rows.end {
 513            return Vec::new();
 514        }
 515
 516        // When the editor is empty and unfocused, then show the placeholder.
 517        if snapshot.is_empty() && !snapshot.is_focused() {
 518            let placeholder_style = self.settings.style.placeholder_text();
 519            let placeholder_text = snapshot.placeholder_text();
 520            let placeholder_lines = placeholder_text
 521                .as_ref()
 522                .map_or("", AsRef::as_ref)
 523                .split('\n')
 524                .skip(rows.start as usize)
 525                .take(rows.len());
 526            return placeholder_lines
 527                .map(|line| {
 528                    cx.text_layout_cache.layout_str(
 529                        line,
 530                        placeholder_style.font_size,
 531                        &[(
 532                            line.len(),
 533                            RunStyle {
 534                                font_id: placeholder_style.font_id,
 535                                color: placeholder_style.color,
 536                                underline: None,
 537                            },
 538                        )],
 539                    )
 540                })
 541                .collect();
 542        }
 543
 544        let style = &self.settings.style;
 545        let mut prev_font_properties = style.text.font_properties.clone();
 546        let mut prev_font_id = style.text.font_id;
 547
 548        let mut layouts = Vec::with_capacity(rows.len());
 549        let mut line = String::new();
 550        let mut styles = Vec::new();
 551        let mut row = rows.start;
 552        let mut line_exceeded_max_len = false;
 553        let chunks = snapshot.chunks(rows.clone(), Some(&style.syntax));
 554
 555        let newline_chunk = Chunk {
 556            text: "\n",
 557            ..Default::default()
 558        };
 559        'outer: for chunk in chunks.chain([newline_chunk]) {
 560            for (ix, mut line_chunk) in chunk.text.split('\n').enumerate() {
 561                if ix > 0 {
 562                    layouts.push(cx.text_layout_cache.layout_str(
 563                        &line,
 564                        style.text.font_size,
 565                        &styles,
 566                    ));
 567                    line.clear();
 568                    styles.clear();
 569                    row += 1;
 570                    line_exceeded_max_len = false;
 571                    if row == rows.end {
 572                        break 'outer;
 573                    }
 574                }
 575
 576                if !line_chunk.is_empty() && !line_exceeded_max_len {
 577                    let highlight_style =
 578                        chunk.highlight_style.unwrap_or(style.text.clone().into());
 579                    // Avoid a lookup if the font properties match the previous ones.
 580                    let font_id = if highlight_style.font_properties == prev_font_properties {
 581                        prev_font_id
 582                    } else {
 583                        cx.font_cache
 584                            .select_font(
 585                                style.text.font_family_id,
 586                                &highlight_style.font_properties,
 587                            )
 588                            .unwrap_or(style.text.font_id)
 589                    };
 590
 591                    if line.len() + line_chunk.len() > MAX_LINE_LEN {
 592                        let mut chunk_len = MAX_LINE_LEN - line.len();
 593                        while !line_chunk.is_char_boundary(chunk_len) {
 594                            chunk_len -= 1;
 595                        }
 596                        line_chunk = &line_chunk[..chunk_len];
 597                        line_exceeded_max_len = true;
 598                    }
 599
 600                    let underline = if let Some(severity) = chunk.diagnostic {
 601                        Some(super::diagnostic_style(severity, true, style).text)
 602                    } else {
 603                        highlight_style.underline
 604                    };
 605
 606                    line.push_str(line_chunk);
 607                    styles.push((
 608                        line_chunk.len(),
 609                        RunStyle {
 610                            font_id,
 611                            color: highlight_style.color,
 612                            underline,
 613                        },
 614                    ));
 615                    prev_font_id = font_id;
 616                    prev_font_properties = highlight_style.font_properties;
 617                }
 618            }
 619        }
 620
 621        layouts
 622    }
 623
 624    fn layout_blocks(
 625        &mut self,
 626        rows: Range<u32>,
 627        snapshot: &EditorSnapshot,
 628        text_width: f32,
 629        line_height: f32,
 630        style: &EditorStyle,
 631        line_layouts: &[text_layout::Line],
 632        cx: &mut LayoutContext,
 633    ) -> Vec<(u32, ElementBox)> {
 634        let mut blocks = Vec::new();
 635
 636        blocks.extend(
 637            snapshot
 638                .blocks_in_range(rows.clone())
 639                .map(|(start_row, block)| {
 640                    let anchor_row = block
 641                        .position()
 642                        .to_point(&snapshot.buffer_snapshot)
 643                        .to_display_point(snapshot)
 644                        .row();
 645
 646                    let anchor_x = if rows.contains(&anchor_row) {
 647                        line_layouts[(anchor_row - rows.start) as usize]
 648                            .x_for_index(block.column() as usize)
 649                    } else {
 650                        layout_line(anchor_row, snapshot, style, cx.text_layout_cache)
 651                            .x_for_index(block.column() as usize)
 652                    };
 653
 654                    let mut element = block.render(&BlockContext { cx, anchor_x });
 655                    element.layout(
 656                        SizeConstraint {
 657                            min: Vector2F::zero(),
 658                            max: vec2f(text_width, block.height() as f32 * line_height),
 659                        },
 660                        cx,
 661                    );
 662                    (start_row, element)
 663                }),
 664        );
 665
 666        blocks.extend(
 667            snapshot
 668                .excerpt_headers_in_range(rows.clone())
 669                .map(|(rows, render)| {
 670                    let mut element = render(cx);
 671                    element.layout(
 672                        SizeConstraint {
 673                            min: Vector2F::zero(),
 674                            max: vec2f(text_width, rows.len() as f32 * line_height),
 675                        },
 676                        cx,
 677                    );
 678                    (rows.start, element)
 679                }),
 680        );
 681
 682        blocks
 683    }
 684}
 685
 686impl Element for EditorElement {
 687    type LayoutState = Option<LayoutState>;
 688    type PaintState = Option<PaintState>;
 689
 690    fn layout(
 691        &mut self,
 692        constraint: SizeConstraint,
 693        cx: &mut LayoutContext,
 694    ) -> (Vector2F, Self::LayoutState) {
 695        let mut size = constraint.max;
 696        if size.x().is_infinite() {
 697            unimplemented!("we don't yet handle an infinite width constraint on buffer elements");
 698        }
 699
 700        let snapshot = self.snapshot(cx.app);
 701        let style = self.settings.style.clone();
 702        let line_height = style.text.line_height(cx.font_cache);
 703
 704        let gutter_padding;
 705        let gutter_width;
 706        if snapshot.mode == EditorMode::Full {
 707            gutter_padding = style.text.em_width(cx.font_cache);
 708            gutter_width = self.max_line_number_width(&snapshot, cx) + gutter_padding * 2.0;
 709        } else {
 710            gutter_padding = 0.0;
 711            gutter_width = 0.0
 712        };
 713
 714        let text_width = size.x() - gutter_width;
 715        let text_offset = vec2f(-style.text.descent(cx.font_cache), 0.);
 716        let em_width = style.text.em_width(cx.font_cache);
 717        let em_advance = style.text.em_advance(cx.font_cache);
 718        let overscroll = vec2f(em_width, 0.);
 719        let wrap_width = match self.settings.soft_wrap {
 720            SoftWrap::None => None,
 721            SoftWrap::EditorWidth => Some(text_width - text_offset.x() - overscroll.x() - em_width),
 722            SoftWrap::Column(column) => Some(column as f32 * em_advance),
 723        };
 724        let snapshot = self.update_view(cx.app, |view, cx| {
 725            if view.set_wrap_width(wrap_width, cx) {
 726                view.snapshot(cx)
 727            } else {
 728                snapshot
 729            }
 730        });
 731
 732        let scroll_height = (snapshot.max_point().row() + 1) as f32 * line_height;
 733        if let EditorMode::AutoHeight { max_lines } = snapshot.mode {
 734            size.set_y(
 735                scroll_height
 736                    .min(constraint.max_along(Axis::Vertical))
 737                    .max(constraint.min_along(Axis::Vertical))
 738                    .min(line_height * max_lines as f32),
 739            )
 740        } else if size.y().is_infinite() {
 741            size.set_y(scroll_height);
 742        }
 743        let gutter_size = vec2f(gutter_width, size.y());
 744        let text_size = vec2f(text_width, size.y());
 745
 746        let (autoscroll_horizontally, mut snapshot) = self.update_view(cx.app, |view, cx| {
 747            let autoscroll_horizontally = view.autoscroll_vertically(size.y(), line_height, cx);
 748            let snapshot = view.snapshot(cx);
 749            (autoscroll_horizontally, snapshot)
 750        });
 751
 752        let scroll_position = snapshot.scroll_position();
 753        let start_row = scroll_position.y() as u32;
 754        let scroll_top = scroll_position.y() * line_height;
 755        let end_row = ((scroll_top + size.y()) / line_height).ceil() as u32 + 1; // Add 1 to ensure selections bleed off screen
 756
 757        let mut active_rows = BTreeMap::new();
 758        let mut highlighted_row = None;
 759        let selections = self.update_view(cx.app, |view, cx| {
 760            highlighted_row = view.highlighted_row();
 761            let selections = view.visible_selections(start_row..end_row, cx);
 762            for (replica_id, selections) in &selections {
 763                if *replica_id == view.replica_id(cx) {
 764                    for selection in selections {
 765                        let is_empty = selection.start == selection.end;
 766                        let selection_start = snapshot.prev_row_boundary(selection.start).0;
 767                        let selection_end = snapshot.next_row_boundary(selection.end).0;
 768                        for row in cmp::max(selection_start.row(), start_row)
 769                            ..=cmp::min(selection_end.row(), end_row)
 770                        {
 771                            let contains_non_empty_selection =
 772                                active_rows.entry(row).or_insert(!is_empty);
 773                            *contains_non_empty_selection |= !is_empty;
 774                        }
 775                    }
 776                }
 777            }
 778            selections
 779        });
 780
 781        let line_number_layouts = self.layout_rows(start_row..end_row, &active_rows, &snapshot, cx);
 782
 783        let mut max_visible_line_width = 0.0;
 784        let line_layouts = self.layout_lines(start_row..end_row, &mut snapshot, cx);
 785        for line in &line_layouts {
 786            if line.width() > max_visible_line_width {
 787                max_visible_line_width = line.width();
 788            }
 789        }
 790
 791        let blocks = self.layout_blocks(
 792            start_row..end_row,
 793            &snapshot,
 794            text_size.x(),
 795            line_height,
 796            &style,
 797            &line_layouts,
 798            cx,
 799        );
 800
 801        let mut layout = LayoutState {
 802            size,
 803            gutter_size,
 804            gutter_padding,
 805            text_size,
 806            overscroll,
 807            text_offset,
 808            snapshot,
 809            style: self.settings.style.clone(),
 810            active_rows,
 811            highlighted_row,
 812            line_layouts,
 813            line_number_layouts,
 814            blocks,
 815            line_height,
 816            em_width,
 817            em_advance,
 818            selections,
 819            max_visible_line_width,
 820        };
 821
 822        let scroll_max = layout.scroll_max(cx.font_cache, cx.text_layout_cache).x();
 823        let scroll_width = layout.scroll_width(cx.text_layout_cache);
 824        let max_glyph_width = style.text.em_width(&cx.font_cache);
 825        self.update_view(cx.app, |view, cx| {
 826            let clamped = view.clamp_scroll_left(scroll_max);
 827            let autoscrolled;
 828            if autoscroll_horizontally {
 829                autoscrolled = view.autoscroll_horizontally(
 830                    start_row,
 831                    layout.text_size.x(),
 832                    scroll_width,
 833                    max_glyph_width,
 834                    &layout.line_layouts,
 835                    cx,
 836                );
 837            } else {
 838                autoscrolled = false;
 839            }
 840
 841            if clamped || autoscrolled {
 842                layout.snapshot = view.snapshot(cx);
 843            }
 844        });
 845
 846        (size, Some(layout))
 847    }
 848
 849    fn paint(
 850        &mut self,
 851        bounds: RectF,
 852        visible_bounds: RectF,
 853        layout: &mut Self::LayoutState,
 854        cx: &mut PaintContext,
 855    ) -> Self::PaintState {
 856        if let Some(layout) = layout {
 857            cx.scene.push_layer(Some(bounds));
 858
 859            let gutter_bounds = RectF::new(bounds.origin(), layout.gutter_size);
 860            let text_bounds = RectF::new(
 861                bounds.origin() + vec2f(layout.gutter_size.x(), 0.0),
 862                layout.text_size,
 863            );
 864
 865            self.paint_background(gutter_bounds, text_bounds, layout, cx);
 866            if layout.gutter_size.x() > 0. {
 867                self.paint_gutter(gutter_bounds, visible_bounds, layout, cx);
 868            }
 869            self.paint_text(text_bounds, visible_bounds, layout, cx);
 870            self.paint_blocks(text_bounds, visible_bounds, layout, cx);
 871
 872            cx.scene.pop_layer();
 873
 874            Some(PaintState {
 875                bounds,
 876                gutter_bounds,
 877                text_bounds,
 878            })
 879        } else {
 880            None
 881        }
 882    }
 883
 884    fn dispatch_event(
 885        &mut self,
 886        event: &Event,
 887        _: RectF,
 888        layout: &mut Self::LayoutState,
 889        paint: &mut Self::PaintState,
 890        cx: &mut EventContext,
 891    ) -> bool {
 892        if let (Some(layout), Some(paint)) = (layout, paint) {
 893            match event {
 894                Event::LeftMouseDown {
 895                    position,
 896                    alt,
 897                    shift,
 898                    click_count,
 899                    ..
 900                } => self.mouse_down(*position, *alt, *shift, *click_count, layout, paint, cx),
 901                Event::LeftMouseUp { position } => self.mouse_up(*position, cx),
 902                Event::LeftMouseDragged { position } => {
 903                    self.mouse_dragged(*position, layout, paint, cx)
 904                }
 905                Event::ScrollWheel {
 906                    position,
 907                    delta,
 908                    precise,
 909                } => self.scroll(*position, *delta, *precise, layout, paint, cx),
 910                Event::KeyDown {
 911                    chars, keystroke, ..
 912                } => self.key_down(chars, keystroke, cx),
 913                _ => false,
 914            }
 915        } else {
 916            false
 917        }
 918    }
 919
 920    fn debug(
 921        &self,
 922        bounds: RectF,
 923        _: &Self::LayoutState,
 924        _: &Self::PaintState,
 925        _: &gpui::DebugContext,
 926    ) -> json::Value {
 927        json!({
 928            "type": "BufferElement",
 929            "bounds": bounds.to_json()
 930        })
 931    }
 932}
 933
 934pub struct LayoutState {
 935    size: Vector2F,
 936    gutter_size: Vector2F,
 937    gutter_padding: f32,
 938    text_size: Vector2F,
 939    style: EditorStyle,
 940    snapshot: EditorSnapshot,
 941    active_rows: BTreeMap<u32, bool>,
 942    highlighted_row: Option<u32>,
 943    line_layouts: Vec<text_layout::Line>,
 944    line_number_layouts: Vec<Option<text_layout::Line>>,
 945    blocks: Vec<(u32, ElementBox)>,
 946    line_height: f32,
 947    em_width: f32,
 948    em_advance: f32,
 949    selections: HashMap<ReplicaId, Vec<text::Selection<DisplayPoint>>>,
 950    overscroll: Vector2F,
 951    text_offset: Vector2F,
 952    max_visible_line_width: f32,
 953}
 954
 955impl LayoutState {
 956    fn scroll_width(&self, layout_cache: &TextLayoutCache) -> f32 {
 957        let row = self.snapshot.longest_row();
 958        let longest_line_width =
 959            layout_line(row, &self.snapshot, &self.style, layout_cache).width();
 960        longest_line_width.max(self.max_visible_line_width) + self.overscroll.x()
 961    }
 962
 963    fn scroll_max(&self, font_cache: &FontCache, layout_cache: &TextLayoutCache) -> Vector2F {
 964        let text_width = self.text_size.x();
 965        let scroll_width = self.scroll_width(layout_cache);
 966        let em_width = self.style.text.em_width(font_cache);
 967        let max_row = self.snapshot.max_point().row();
 968
 969        vec2f(
 970            ((scroll_width - text_width) / em_width).max(0.0),
 971            max_row.saturating_sub(1) as f32,
 972        )
 973    }
 974}
 975
 976fn layout_line(
 977    row: u32,
 978    snapshot: &EditorSnapshot,
 979    style: &EditorStyle,
 980    layout_cache: &TextLayoutCache,
 981) -> text_layout::Line {
 982    let mut line = snapshot.line(row);
 983
 984    if line.len() > MAX_LINE_LEN {
 985        let mut len = MAX_LINE_LEN;
 986        while !line.is_char_boundary(len) {
 987            len -= 1;
 988        }
 989        line.truncate(len);
 990    }
 991
 992    layout_cache.layout_str(
 993        &line,
 994        style.text.font_size,
 995        &[(
 996            snapshot.line_len(row) as usize,
 997            RunStyle {
 998                font_id: style.text.font_id,
 999                color: Color::black(),
1000                underline: None,
1001            },
1002        )],
1003    )
1004}
1005
1006pub struct PaintState {
1007    bounds: RectF,
1008    gutter_bounds: RectF,
1009    text_bounds: RectF,
1010}
1011
1012impl PaintState {
1013    fn point_for_position(
1014        &self,
1015        snapshot: &EditorSnapshot,
1016        layout: &LayoutState,
1017        position: Vector2F,
1018    ) -> (DisplayPoint, u32) {
1019        let scroll_position = snapshot.scroll_position();
1020        let position = position - self.text_bounds.origin();
1021        let y = position.y().max(0.0).min(layout.size.y());
1022        let row = ((y / layout.line_height) + scroll_position.y()) as u32;
1023        let row = cmp::min(row, snapshot.max_point().row());
1024        let line = &layout.line_layouts[(row - scroll_position.y() as u32) as usize];
1025        let x = position.x() + (scroll_position.x() * layout.em_width);
1026
1027        let column = if x >= 0.0 {
1028            line.index_for_x(x)
1029                .map(|ix| ix as u32)
1030                .unwrap_or_else(|| snapshot.line_len(row))
1031        } else {
1032            0
1033        };
1034        let overshoot = (0f32.max(x - line.width()) / layout.em_advance) as u32;
1035
1036        (DisplayPoint::new(row, column), overshoot)
1037    }
1038}
1039
1040struct Cursor {
1041    origin: Vector2F,
1042    line_height: f32,
1043    color: Color,
1044}
1045
1046impl Cursor {
1047    fn paint(&self, cx: &mut PaintContext) {
1048        cx.scene.push_quad(Quad {
1049            bounds: RectF::new(self.origin, vec2f(2.0, self.line_height)),
1050            background: Some(self.color),
1051            border: Border::new(0., Color::black()),
1052            corner_radius: 0.,
1053        });
1054    }
1055}
1056
1057#[derive(Debug)]
1058struct Selection {
1059    start_y: f32,
1060    line_height: f32,
1061    lines: Vec<SelectionLine>,
1062    color: Color,
1063}
1064
1065#[derive(Debug)]
1066struct SelectionLine {
1067    start_x: f32,
1068    end_x: f32,
1069}
1070
1071impl Selection {
1072    fn paint(&self, bounds: RectF, scene: &mut Scene) {
1073        if self.lines.len() >= 2 && self.lines[0].start_x > self.lines[1].end_x {
1074            self.paint_lines(self.start_y, &self.lines[0..1], bounds, scene);
1075            self.paint_lines(
1076                self.start_y + self.line_height,
1077                &self.lines[1..],
1078                bounds,
1079                scene,
1080            );
1081        } else {
1082            self.paint_lines(self.start_y, &self.lines, bounds, scene);
1083        }
1084    }
1085
1086    fn paint_lines(&self, start_y: f32, lines: &[SelectionLine], bounds: RectF, scene: &mut Scene) {
1087        if lines.is_empty() {
1088            return;
1089        }
1090
1091        let mut path = PathBuilder::new();
1092        let corner_radius = 0.15 * self.line_height;
1093        let first_line = lines.first().unwrap();
1094        let last_line = lines.last().unwrap();
1095
1096        let first_top_left = vec2f(first_line.start_x, start_y);
1097        let first_top_right = vec2f(first_line.end_x, start_y);
1098
1099        let curve_height = vec2f(0., corner_radius);
1100        let curve_width = |start_x: f32, end_x: f32| {
1101            let max = (end_x - start_x) / 2.;
1102            let width = if max < corner_radius {
1103                max
1104            } else {
1105                corner_radius
1106            };
1107
1108            vec2f(width, 0.)
1109        };
1110
1111        let top_curve_width = curve_width(first_line.start_x, first_line.end_x);
1112        path.reset(first_top_right - top_curve_width);
1113        path.curve_to(first_top_right + curve_height, first_top_right);
1114
1115        let mut iter = lines.iter().enumerate().peekable();
1116        while let Some((ix, line)) = iter.next() {
1117            let bottom_right = vec2f(line.end_x, start_y + (ix + 1) as f32 * self.line_height);
1118
1119            if let Some((_, next_line)) = iter.peek() {
1120                let next_top_right = vec2f(next_line.end_x, bottom_right.y());
1121
1122                match next_top_right.x().partial_cmp(&bottom_right.x()).unwrap() {
1123                    Ordering::Equal => {
1124                        path.line_to(bottom_right);
1125                    }
1126                    Ordering::Less => {
1127                        let curve_width = curve_width(next_top_right.x(), bottom_right.x());
1128                        path.line_to(bottom_right - curve_height);
1129                        path.curve_to(bottom_right - curve_width, bottom_right);
1130                        path.line_to(next_top_right + curve_width);
1131                        path.curve_to(next_top_right + curve_height, next_top_right);
1132                    }
1133                    Ordering::Greater => {
1134                        let curve_width = curve_width(bottom_right.x(), next_top_right.x());
1135                        path.line_to(bottom_right - curve_height);
1136                        path.curve_to(bottom_right + curve_width, bottom_right);
1137                        path.line_to(next_top_right - curve_width);
1138                        path.curve_to(next_top_right + curve_height, next_top_right);
1139                    }
1140                }
1141            } else {
1142                let curve_width = curve_width(line.start_x, line.end_x);
1143                path.line_to(bottom_right - curve_height);
1144                path.curve_to(bottom_right - curve_width, bottom_right);
1145
1146                let bottom_left = vec2f(line.start_x, bottom_right.y());
1147                path.line_to(bottom_left + curve_width);
1148                path.curve_to(bottom_left - curve_height, bottom_left);
1149            }
1150        }
1151
1152        if first_line.start_x > last_line.start_x {
1153            let curve_width = curve_width(last_line.start_x, first_line.start_x);
1154            let second_top_left = vec2f(last_line.start_x, start_y + self.line_height);
1155            path.line_to(second_top_left + curve_height);
1156            path.curve_to(second_top_left + curve_width, second_top_left);
1157            let first_bottom_left = vec2f(first_line.start_x, second_top_left.y());
1158            path.line_to(first_bottom_left - curve_width);
1159            path.curve_to(first_bottom_left - curve_height, first_bottom_left);
1160        }
1161
1162        path.line_to(first_top_left + curve_height);
1163        path.curve_to(first_top_left + top_curve_width, first_top_left);
1164        path.line_to(first_top_right - top_curve_width);
1165
1166        scene.push_path(path.build(self.color, Some(bounds)));
1167    }
1168}
1169
1170fn scale_vertical_mouse_autoscroll_delta(delta: f32) -> f32 {
1171    delta.powf(1.5) / 100.0
1172}
1173
1174fn scale_horizontal_mouse_autoscroll_delta(delta: f32) -> f32 {
1175    delta.powf(1.2) / 300.0
1176}
1177
1178#[cfg(test)]
1179mod tests {
1180    use super::*;
1181    use crate::{Editor, EditorSettings, MultiBuffer};
1182    use std::sync::Arc;
1183    use util::test::sample_text;
1184
1185    #[gpui::test]
1186    fn test_layout_line_numbers(cx: &mut gpui::MutableAppContext) {
1187        let settings = EditorSettings::test(cx);
1188        let buffer = MultiBuffer::build_simple(&sample_text(6, 6, 'a'), cx);
1189        let (window_id, editor) = cx.add_window(Default::default(), |cx| {
1190            Editor::for_buffer(
1191                buffer,
1192                {
1193                    let settings = settings.clone();
1194                    Arc::new(move |_| settings.clone())
1195                },
1196                cx,
1197            )
1198        });
1199        let element = EditorElement::new(editor.downgrade(), settings);
1200
1201        let layouts = editor.update(cx, |editor, cx| {
1202            let snapshot = editor.snapshot(cx);
1203            let mut presenter = cx.build_presenter(window_id, 30.);
1204            let mut layout_cx = presenter.build_layout_context(false, cx);
1205            element.layout_rows(0..6, &Default::default(), &snapshot, &mut layout_cx)
1206        });
1207        assert_eq!(layouts.len(), 6);
1208    }
1209}