element.rs

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