element.rs

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