terminal_element.rs

  1use alacritty_terminal::{
  2    ansi::{Color as AnsiColor, Color::Named, CursorShape as AlacCursorShape, NamedColor},
  3    grid::Dimensions,
  4    index::Point,
  5    term::{cell::Flags, TermMode},
  6};
  7use editor::{Cursor, CursorShape, HighlightedRange, HighlightedRangeLine};
  8use gpui::{
  9    color::Color,
 10    fonts::{Properties, Style::Italic, TextStyle, Underline, Weight},
 11    geometry::{
 12        rect::RectF,
 13        vector::{vec2f, Vector2F},
 14    },
 15    serde_json::json,
 16    text_layout::{Line, RunStyle},
 17    Element, Event, EventContext, FontCache, KeyDownEvent, ModelContext, MouseButton, MouseRegion,
 18    PaintContext, Quad, TextLayoutCache, WeakModelHandle, WeakViewHandle,
 19};
 20use itertools::Itertools;
 21use ordered_float::OrderedFloat;
 22use settings::Settings;
 23use theme::TerminalStyle;
 24use util::ResultExt;
 25
 26use std::{fmt::Debug, ops::RangeInclusive};
 27use std::{mem, ops::Range};
 28
 29use crate::{
 30    mappings::colors::convert_color,
 31    terminal_view::{DeployContextMenu, TerminalView},
 32    IndexedCell, Terminal, TerminalContent, TerminalSize,
 33};
 34
 35///The information generated during layout that is nescessary for painting
 36pub struct LayoutState {
 37    cells: Vec<LayoutCell>,
 38    rects: Vec<LayoutRect>,
 39    relative_highlighted_ranges: Vec<(RangeInclusive<Point>, Color)>,
 40    cursor: Option<Cursor>,
 41    background_color: Color,
 42    size: TerminalSize,
 43    mode: TermMode,
 44    display_offset: usize,
 45}
 46
 47///Helper struct for converting data between alacritty's cursor points, and displayed cursor points
 48struct DisplayCursor {
 49    line: i32,
 50    col: usize,
 51}
 52
 53impl DisplayCursor {
 54    fn from(cursor_point: Point, display_offset: usize) -> Self {
 55        Self {
 56            line: cursor_point.line.0 + display_offset as i32,
 57            col: cursor_point.column.0,
 58        }
 59    }
 60
 61    pub fn line(&self) -> i32 {
 62        self.line
 63    }
 64
 65    pub fn col(&self) -> usize {
 66        self.col
 67    }
 68}
 69
 70#[derive(Clone, Debug, Default)]
 71struct LayoutCell {
 72    point: Point<i32, i32>,
 73    text: Line,
 74}
 75
 76impl LayoutCell {
 77    fn new(point: Point<i32, i32>, text: Line) -> LayoutCell {
 78        LayoutCell { point, text }
 79    }
 80
 81    fn paint(
 82        &self,
 83        origin: Vector2F,
 84        layout: &LayoutState,
 85        visible_bounds: RectF,
 86        cx: &mut PaintContext,
 87    ) {
 88        let pos = {
 89            let point = self.point;
 90            vec2f(
 91                (origin.x() + point.column as f32 * layout.size.cell_width).floor(),
 92                origin.y() + point.line as f32 * layout.size.line_height,
 93            )
 94        };
 95
 96        self.text
 97            .paint(pos, visible_bounds, layout.size.line_height, cx);
 98    }
 99}
100
101#[derive(Clone, Debug, Default)]
102struct LayoutRect {
103    point: Point<i32, i32>,
104    num_of_cells: usize,
105    color: Color,
106}
107
108impl LayoutRect {
109    fn new(point: Point<i32, i32>, num_of_cells: usize, color: Color) -> LayoutRect {
110        LayoutRect {
111            point,
112            num_of_cells,
113            color,
114        }
115    }
116
117    fn extend(&self) -> Self {
118        LayoutRect {
119            point: self.point,
120            num_of_cells: self.num_of_cells + 1,
121            color: self.color,
122        }
123    }
124
125    fn paint(&self, origin: Vector2F, layout: &LayoutState, cx: &mut PaintContext) {
126        let position = {
127            let point = self.point;
128            vec2f(
129                (origin.x() + point.column as f32 * layout.size.cell_width).floor(),
130                origin.y() + point.line as f32 * layout.size.line_height,
131            )
132        };
133        let size = vec2f(
134            (layout.size.cell_width * self.num_of_cells as f32).ceil(),
135            layout.size.line_height,
136        );
137
138        cx.scene.push_quad(Quad {
139            bounds: RectF::new(position, size),
140            background: Some(self.color),
141            border: Default::default(),
142            corner_radius: 0.,
143        })
144    }
145}
146
147///The GPUI element that paints the terminal.
148///We need to keep a reference to the view for mouse events, do we need it for any other terminal stuff, or can we move that to connection?
149pub struct TerminalElement {
150    terminal: WeakModelHandle<Terminal>,
151    view: WeakViewHandle<TerminalView>,
152    focused: bool,
153    cursor_visible: bool,
154}
155
156impl TerminalElement {
157    pub fn new(
158        view: WeakViewHandle<TerminalView>,
159        terminal: WeakModelHandle<Terminal>,
160        focused: bool,
161        cursor_visible: bool,
162    ) -> TerminalElement {
163        TerminalElement {
164            view,
165            terminal,
166            focused,
167            cursor_visible,
168        }
169    }
170
171    //Vec<Range<Point>> -> Clip out the parts of the ranges
172
173    fn layout_grid(
174        grid: &Vec<IndexedCell>,
175        text_style: &TextStyle,
176        terminal_theme: &TerminalStyle,
177        text_layout_cache: &TextLayoutCache,
178        font_cache: &FontCache,
179    ) -> (Vec<LayoutCell>, Vec<LayoutRect>) {
180        let mut cells = vec![];
181        let mut rects = vec![];
182
183        let mut cur_rect: Option<LayoutRect> = None;
184        let mut cur_alac_color = None;
185
186        let linegroups = grid.into_iter().group_by(|i| i.point.line);
187        for (line_index, (_, line)) in linegroups.into_iter().enumerate() {
188            for cell in line {
189                let mut fg = cell.fg;
190                let mut bg = cell.bg;
191                if cell.flags.contains(Flags::INVERSE) {
192                    mem::swap(&mut fg, &mut bg);
193                }
194
195                //Expand background rect range
196                {
197                    if matches!(bg, Named(NamedColor::Background)) {
198                        //Continue to next cell, resetting variables if nescessary
199                        cur_alac_color = None;
200                        if let Some(rect) = cur_rect {
201                            rects.push(rect);
202                            cur_rect = None
203                        }
204                    } else {
205                        match cur_alac_color {
206                            Some(cur_color) => {
207                                if bg == cur_color {
208                                    cur_rect = cur_rect.take().map(|rect| rect.extend());
209                                } else {
210                                    cur_alac_color = Some(bg);
211                                    if cur_rect.is_some() {
212                                        rects.push(cur_rect.take().unwrap());
213                                    }
214                                    cur_rect = Some(LayoutRect::new(
215                                        Point::new(line_index as i32, cell.point.column.0 as i32),
216                                        1,
217                                        convert_color(&bg, &terminal_theme),
218                                    ));
219                                }
220                            }
221                            None => {
222                                cur_alac_color = Some(bg);
223                                cur_rect = Some(LayoutRect::new(
224                                    Point::new(line_index as i32, cell.point.column.0 as i32),
225                                    1,
226                                    convert_color(&bg, &terminal_theme),
227                                ));
228                            }
229                        }
230                    }
231                }
232
233                //Layout current cell text
234                {
235                    let cell_text = &cell.c.to_string();
236                    if cell_text != " " {
237                        let cell_style = TerminalElement::cell_style(
238                            &cell,
239                            fg,
240                            terminal_theme,
241                            text_style,
242                            font_cache,
243                        );
244
245                        let layout_cell = text_layout_cache.layout_str(
246                            cell_text,
247                            text_style.font_size,
248                            &[(cell_text.len(), cell_style)],
249                        );
250
251                        cells.push(LayoutCell::new(
252                            Point::new(line_index as i32, cell.point.column.0 as i32),
253                            layout_cell,
254                        ))
255                    }
256                };
257            }
258
259            if cur_rect.is_some() {
260                rects.push(cur_rect.take().unwrap());
261            }
262        }
263        (cells, rects)
264    }
265
266    // Compute the cursor position and expected block width, may return a zero width if x_for_index returns
267    // the same position for sequential indexes. Use em_width instead
268    fn shape_cursor(
269        cursor_point: DisplayCursor,
270        size: TerminalSize,
271        text_fragment: &Line,
272    ) -> Option<(Vector2F, f32)> {
273        if cursor_point.line() < size.total_lines() as i32 {
274            let cursor_width = if text_fragment.width() == 0. {
275                size.cell_width()
276            } else {
277                text_fragment.width()
278            };
279
280            //Cursor should always surround as much of the text as possible,
281            //hence when on pixel boundaries round the origin down and the width up
282            Some((
283                vec2f(
284                    (cursor_point.col() as f32 * size.cell_width()).floor(),
285                    (cursor_point.line() as f32 * size.line_height()).floor(),
286                ),
287                cursor_width.ceil(),
288            ))
289        } else {
290            None
291        }
292    }
293
294    ///Convert the Alacritty cell styles to GPUI text styles and background color
295    fn cell_style(
296        indexed: &IndexedCell,
297        fg: AnsiColor,
298        style: &TerminalStyle,
299        text_style: &TextStyle,
300        font_cache: &FontCache,
301    ) -> RunStyle {
302        let flags = indexed.cell.flags;
303        let fg = convert_color(&fg, &style);
304
305        let underline = flags
306            .intersects(Flags::ALL_UNDERLINES)
307            .then(|| Underline {
308                color: Some(fg),
309                squiggly: flags.contains(Flags::UNDERCURL),
310                thickness: OrderedFloat(1.),
311            })
312            .unwrap_or_default();
313
314        let mut properties = Properties::new();
315        if indexed
316            .flags
317            .intersects(Flags::BOLD | Flags::BOLD_ITALIC | Flags::DIM_BOLD)
318        {
319            properties = *properties.weight(Weight::BOLD);
320        }
321        if indexed.flags.intersects(Flags::ITALIC | Flags::BOLD_ITALIC) {
322            properties = *properties.style(Italic);
323        }
324
325        let font_id = font_cache
326            .select_font(text_style.font_family_id, &properties)
327            .unwrap_or(text_style.font_id);
328
329        RunStyle {
330            color: fg,
331            font_id,
332            underline,
333        }
334    }
335
336    fn generic_button_handler<E>(
337        connection: WeakModelHandle<Terminal>,
338        origin: Vector2F,
339        f: impl Fn(&mut Terminal, Vector2F, E, &mut ModelContext<Terminal>),
340    ) -> impl Fn(E, &mut EventContext) {
341        move |event, cx| {
342            cx.focus_parent_view();
343            if let Some(conn_handle) = connection.upgrade(cx.app) {
344                conn_handle.update(cx.app, |terminal, cx| {
345                    f(terminal, origin, event, cx);
346
347                    cx.notify();
348                })
349            }
350        }
351    }
352
353    fn attach_mouse_handlers(
354        &self,
355        origin: Vector2F,
356        view_id: usize,
357        visible_bounds: RectF,
358        mode: TermMode,
359        cx: &mut PaintContext,
360    ) {
361        let connection = self.terminal;
362
363        let mut region = MouseRegion::new::<Self>(view_id, view_id, visible_bounds);
364
365        // Terminal Emulator controlled behavior:
366        region = region
367            // Start selections
368            .on_down(
369                MouseButton::Left,
370                TerminalElement::generic_button_handler(
371                    connection,
372                    origin,
373                    move |terminal, origin, e, _cx| {
374                        terminal.mouse_down(&e, origin);
375                    },
376                ),
377            )
378            // Update drag selections
379            .on_drag(MouseButton::Left, move |event, cx| {
380                if cx.is_parent_view_focused() {
381                    if let Some(conn_handle) = connection.upgrade(cx.app) {
382                        conn_handle.update(cx.app, |terminal, cx| {
383                            terminal.mouse_drag(event, origin);
384                            cx.notify();
385                        })
386                    }
387                }
388            })
389            // Copy on up behavior
390            .on_up(
391                MouseButton::Left,
392                TerminalElement::generic_button_handler(
393                    connection,
394                    origin,
395                    move |terminal, origin, e, _cx| {
396                        terminal.mouse_up(&e, origin);
397                    },
398                ),
399            )
400            // Handle click based selections
401            .on_click(
402                MouseButton::Left,
403                TerminalElement::generic_button_handler(
404                    connection,
405                    origin,
406                    move |terminal, origin, e, _cx| {
407                        terminal.left_click(&e, origin);
408                    },
409                ),
410            )
411            // Context menu
412            .on_click(MouseButton::Right, move |e, cx| {
413                let mouse_mode = if let Some(conn_handle) = connection.upgrade(cx.app) {
414                    conn_handle.update(cx.app, |terminal, _cx| terminal.mouse_mode(e.shift))
415                } else {
416                    // If we can't get the model handle, probably can't deploy the context menu
417                    true
418                };
419                if !mouse_mode {
420                    cx.dispatch_action(DeployContextMenu {
421                        position: e.position,
422                    });
423                }
424            })
425            .on_scroll(TerminalElement::generic_button_handler(
426                connection,
427                origin,
428                move |terminal, origin, e, _cx| {
429                    terminal.scroll_wheel(e, origin);
430                },
431            ));
432
433        // Mouse mode handlers:
434        // All mouse modes need the extra click handlers
435        if mode.intersects(TermMode::MOUSE_MODE) {
436            region = region
437                .on_down(
438                    MouseButton::Right,
439                    TerminalElement::generic_button_handler(
440                        connection,
441                        origin,
442                        move |terminal, origin, e, _cx| {
443                            terminal.mouse_down(&e, origin);
444                        },
445                    ),
446                )
447                .on_down(
448                    MouseButton::Middle,
449                    TerminalElement::generic_button_handler(
450                        connection,
451                        origin,
452                        move |terminal, origin, e, _cx| {
453                            terminal.mouse_down(&e, origin);
454                        },
455                    ),
456                )
457                .on_up(
458                    MouseButton::Right,
459                    TerminalElement::generic_button_handler(
460                        connection,
461                        origin,
462                        move |terminal, origin, e, _cx| {
463                            terminal.mouse_up(&e, origin);
464                        },
465                    ),
466                )
467                .on_up(
468                    MouseButton::Middle,
469                    TerminalElement::generic_button_handler(
470                        connection,
471                        origin,
472                        move |terminal, origin, e, _cx| {
473                            terminal.mouse_up(&e, origin);
474                        },
475                    ),
476                )
477        }
478        //Mouse move manages both dragging and motion events
479        if mode.intersects(TermMode::MOUSE_DRAG | TermMode::MOUSE_MOTION) {
480            region = region
481                //TODO: This does not fire on right-mouse-down-move events.
482                .on_move(move |event, cx| {
483                    if cx.is_parent_view_focused() {
484                        if let Some(conn_handle) = connection.upgrade(cx.app) {
485                            conn_handle.update(cx.app, |terminal, cx| {
486                                terminal.mouse_move(&event, origin);
487                                cx.notify();
488                            })
489                        }
490                    }
491                })
492        }
493
494        cx.scene.push_mouse_region(region);
495    }
496
497    ///Configures a text style from the current settings.
498    pub fn make_text_style(font_cache: &FontCache, settings: &Settings) -> TextStyle {
499        // Pull the font family from settings properly overriding
500        let family_id = settings
501            .terminal_overrides
502            .font_family
503            .as_ref()
504            .or(settings.terminal_defaults.font_family.as_ref())
505            .and_then(|family_name| font_cache.load_family(&[family_name]).log_err())
506            .unwrap_or(settings.buffer_font_family);
507
508        let font_size = settings
509            .terminal_overrides
510            .font_size
511            .or(settings.terminal_defaults.font_size)
512            .unwrap_or(settings.buffer_font_size);
513
514        let font_id = font_cache
515            .select_font(family_id, &Default::default())
516            .unwrap();
517
518        TextStyle {
519            color: settings.theme.editor.text_color,
520            font_family_id: family_id,
521            font_family_name: font_cache.family_name(family_id).unwrap(),
522            font_id,
523            font_size,
524            font_properties: Default::default(),
525            underline: Default::default(),
526        }
527    }
528}
529
530impl Element for TerminalElement {
531    type LayoutState = LayoutState;
532    type PaintState = ();
533
534    fn layout(
535        &mut self,
536        constraint: gpui::SizeConstraint,
537        cx: &mut gpui::LayoutContext,
538    ) -> (gpui::geometry::vector::Vector2F, Self::LayoutState) {
539        let settings = cx.global::<Settings>();
540        let font_cache = cx.font_cache();
541
542        //Setup layout information
543        let terminal_theme = settings.theme.terminal.clone(); //TODO: Try to minimize this clone.
544        let text_style = TerminalElement::make_text_style(font_cache, settings);
545        let selection_color = settings.theme.editor.selection.selection;
546        let match_color = settings.theme.search.match_background;
547        let dimensions = {
548            let line_height = font_cache.line_height(text_style.font_size);
549            let cell_width = font_cache.em_advance(text_style.font_id, text_style.font_size);
550            TerminalSize::new(line_height, cell_width, constraint.max)
551        };
552
553        let search_matches = if let Some(terminal_model) = self.terminal.upgrade(cx) {
554            terminal_model.read(cx).matches.clone()
555        } else {
556            Default::default()
557        };
558
559        let background_color = terminal_theme.background;
560        let terminal_handle = self.terminal.upgrade(cx).unwrap();
561
562        terminal_handle.update(cx.app, |terminal, cx| {
563            terminal.set_size(dimensions);
564            terminal.try_sync(cx)
565        });
566
567        let TerminalContent {
568            cells,
569            mode,
570            display_offset,
571            cursor_char,
572            selection,
573            cursor,
574            ..
575        } = &terminal_handle.read(cx).last_content;
576
577        // searches, highlights to a single range representations
578        let mut relative_highlighted_ranges = Vec::new();
579        for search_match in search_matches {
580            relative_highlighted_ranges.push((search_match, match_color))
581        }
582        if let Some(selection) = selection {
583            relative_highlighted_ranges.push((selection.start..=selection.end, selection_color));
584        }
585
586        // then have that representation be converted to the appropriate highlight data structure
587
588        let (cells, rects) = TerminalElement::layout_grid(
589            cells,
590            &text_style,
591            &terminal_theme,
592            cx.text_layout_cache,
593            cx.font_cache(),
594        );
595
596        //Layout cursor. Rectangle is used for IME, so we should lay it out even
597        //if we don't end up showing it.
598        let cursor = if let AlacCursorShape::Hidden = cursor.shape {
599            None
600        } else {
601            let cursor_point = DisplayCursor::from(cursor.point, *display_offset);
602            let cursor_text = {
603                let str_trxt = cursor_char.to_string();
604
605                let color = if self.focused {
606                    terminal_theme.background
607                } else {
608                    terminal_theme.foreground
609                };
610
611                cx.text_layout_cache.layout_str(
612                    &str_trxt,
613                    text_style.font_size,
614                    &[(
615                        str_trxt.len(),
616                        RunStyle {
617                            font_id: text_style.font_id,
618                            color,
619                            underline: Default::default(),
620                        },
621                    )],
622                )
623            };
624
625            TerminalElement::shape_cursor(cursor_point, dimensions, &cursor_text).map(
626                move |(cursor_position, block_width)| {
627                    let shape = match cursor.shape {
628                        AlacCursorShape::Block if !self.focused => CursorShape::Hollow,
629                        AlacCursorShape::Block => CursorShape::Block,
630                        AlacCursorShape::Underline => CursorShape::Underscore,
631                        AlacCursorShape::Beam => CursorShape::Bar,
632                        AlacCursorShape::HollowBlock => CursorShape::Hollow,
633                        //This case is handled in the if wrapping the whole cursor layout
634                        AlacCursorShape::Hidden => unreachable!(),
635                    };
636
637                    Cursor::new(
638                        cursor_position,
639                        block_width,
640                        dimensions.line_height,
641                        terminal_theme.cursor,
642                        shape,
643                        Some(cursor_text),
644                    )
645                },
646            )
647        };
648
649        //Done!
650        (
651            constraint.max,
652            LayoutState {
653                cells,
654                cursor,
655                background_color,
656                size: dimensions,
657                rects,
658                relative_highlighted_ranges,
659                mode: *mode,
660                display_offset: *display_offset,
661            },
662        )
663    }
664
665    fn paint(
666        &mut self,
667        bounds: gpui::geometry::rect::RectF,
668        visible_bounds: gpui::geometry::rect::RectF,
669        layout: &mut Self::LayoutState,
670        cx: &mut gpui::PaintContext,
671    ) -> Self::PaintState {
672        //Setup element stuff
673        let clip_bounds = Some(visible_bounds);
674
675        cx.paint_layer(clip_bounds, |cx| {
676            let origin = bounds.origin() + vec2f(layout.size.cell_width, 0.);
677
678            //Elements are ephemeral, only at paint time do we know what could be clicked by a mouse
679            self.attach_mouse_handlers(origin, self.view.id(), visible_bounds, layout.mode, cx);
680
681            cx.scene.push_cursor_region(gpui::CursorRegion {
682                bounds,
683                style: gpui::CursorStyle::IBeam,
684            });
685
686            cx.paint_layer(clip_bounds, |cx| {
687                //Start with a background color
688                cx.scene.push_quad(Quad {
689                    bounds: RectF::new(bounds.origin(), bounds.size()),
690                    background: Some(layout.background_color),
691                    border: Default::default(),
692                    corner_radius: 0.,
693                });
694
695                for rect in &layout.rects {
696                    rect.paint(origin, layout, cx)
697                }
698            });
699
700            //Draw Highlighted Backgrounds
701            cx.paint_layer(clip_bounds, |cx| {
702                for (relative_highlighted_range, color) in layout.relative_highlighted_ranges.iter()
703                {
704                    if let Some((start_y, highlighted_range_lines)) =
705                        to_highlighted_range_lines(relative_highlighted_range, layout, origin)
706                    {
707                        let hr = HighlightedRange {
708                            start_y, //Need to change this
709                            line_height: layout.size.line_height,
710                            lines: highlighted_range_lines,
711                            color: color.clone(),
712                            //Copied from editor. TODO: move to theme or something
713                            corner_radius: 0.15 * layout.size.line_height,
714                        };
715                        hr.paint(bounds, cx.scene);
716                    }
717                }
718            });
719
720            //Draw the text cells
721            cx.paint_layer(clip_bounds, |cx| {
722                for cell in &layout.cells {
723                    cell.paint(origin, layout, visible_bounds, cx);
724                }
725            });
726
727            //Draw cursor
728            if self.cursor_visible {
729                if let Some(cursor) = &layout.cursor {
730                    cx.paint_layer(clip_bounds, |cx| {
731                        cursor.paint(origin, cx);
732                    })
733                }
734            }
735        });
736    }
737
738    fn dispatch_event(
739        &mut self,
740        event: &gpui::Event,
741        _bounds: gpui::geometry::rect::RectF,
742        _visible_bounds: gpui::geometry::rect::RectF,
743        _layout: &mut Self::LayoutState,
744        _paint: &mut Self::PaintState,
745        cx: &mut gpui::EventContext,
746    ) -> bool {
747        if let Event::KeyDown(KeyDownEvent { keystroke, .. }) = event {
748            if !cx.is_parent_view_focused() {
749                return false;
750            }
751
752            if let Some(view) = self.view.upgrade(cx.app) {
753                view.update(cx.app, |view, cx| {
754                    view.clear_bel(cx);
755                    view.pause_cursor_blinking(cx);
756                })
757            }
758
759            self.terminal
760                .upgrade(cx.app)
761                .map(|model_handle| {
762                    model_handle.update(cx.app, |term, cx| {
763                        term.try_keystroke(
764                            keystroke,
765                            cx.global::<Settings>()
766                                .terminal_overrides
767                                .option_as_meta
768                                .unwrap_or(false),
769                        )
770                    })
771                })
772                .unwrap_or(false)
773        } else {
774            false
775        }
776    }
777
778    fn metadata(&self) -> Option<&dyn std::any::Any> {
779        None
780    }
781
782    fn debug(
783        &self,
784        _bounds: gpui::geometry::rect::RectF,
785        _layout: &Self::LayoutState,
786        _paint: &Self::PaintState,
787        _cx: &gpui::DebugContext,
788    ) -> gpui::serde_json::Value {
789        json!({
790            "type": "TerminalElement",
791        })
792    }
793
794    fn rect_for_text_range(
795        &self,
796        _: Range<usize>,
797        bounds: RectF,
798        _: RectF,
799        layout: &Self::LayoutState,
800        _: &Self::PaintState,
801        _: &gpui::MeasurementContext,
802    ) -> Option<RectF> {
803        // Use the same origin that's passed to `Cursor::paint` in the paint
804        // method bove.
805        let mut origin = bounds.origin() + vec2f(layout.size.cell_width, 0.);
806
807        // TODO - Why is it necessary to move downward one line to get correct
808        // positioning? I would think that we'd want the same rect that is
809        // painted for the cursor.
810        origin += vec2f(0., layout.size.line_height);
811
812        Some(layout.cursor.as_ref()?.bounding_rect(origin))
813    }
814}
815
816fn to_highlighted_range_lines(
817    range: &RangeInclusive<Point>,
818    layout: &LayoutState,
819    origin: Vector2F,
820) -> Option<(f32, Vec<HighlightedRangeLine>)> {
821    // Step 1. Normalize the points to be viewport relative.
822    // When display_offset = 1, here's how the grid is arranged:
823    //-2,0 -2,1...
824    //--- Viewport top
825    //-1,0 -1,1...
826    //--------- Terminal Top
827    // 0,0  0,1...
828    // 1,0  1,1...
829    //--- Viewport Bottom
830    // 2,0  2,1...
831    //--------- Terminal Bottom
832
833    // Normalize to viewport relative, from terminal relative.
834    // lines are i32s, which are negative above the top left corner of the terminal
835    // If the user has scrolled, we use the display_offset to tell us which offset
836    // of the grid data we should be looking at. But for the rendering step, we don't
837    // want negatives. We want things relative to the 'viewport' (the area of the grid
838    // which is currently shown according to the display offset)
839    let unclamped_start = Point::new(
840        range.start().line + layout.display_offset,
841        range.start().column,
842    );
843    let unclamped_end = Point::new(range.end().line + layout.display_offset, range.end().column);
844
845    // Step 2. Clamp range to viewport, and return None if it doesn't overlap
846    if unclamped_end.line.0 < 0 || unclamped_start.line.0 > layout.size.num_lines() as i32 {
847        return None;
848    }
849
850    let clamped_start_line = unclamped_start.line.0.max(0) as usize;
851    let clamped_end_line = unclamped_end.line.0.min(layout.size.num_lines() as i32) as usize;
852    //Convert the start of the range to pixels
853    let start_y = origin.y() + clamped_start_line as f32 * layout.size.line_height;
854
855    // Step 3. Expand ranges that cross lines into a collection of single-line ranges.
856    //  (also convert to pixels)
857    let mut highlighted_range_lines = Vec::new();
858    for line in clamped_start_line..=clamped_end_line {
859        let mut line_start = 0;
860        let mut line_end = layout.size.columns();
861
862        if line == clamped_start_line {
863            line_start = unclamped_start.column.0 as usize;
864        }
865        if line == clamped_end_line {
866            line_end = unclamped_end.column.0 as usize + 1; //+1 for inclusive
867        }
868
869        highlighted_range_lines.push(HighlightedRangeLine {
870            start_x: origin.x() + line_start as f32 * layout.size.cell_width,
871            end_x: origin.x() + line_end as f32 * layout.size.cell_width,
872        });
873    }
874
875    Some((start_y, highlighted_range_lines))
876}