element.rs

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