use std::{cmp, f32};
use gpui::{px, Pixels, ViewContext};
use language::Point;
use crate::{display_map::ToDisplayPoint, Editor, EditorMode, LineWithInvisibles};
#[derive(PartialEq, Eq)]
pub enum Autoscroll {
Next,
Strategy(AutoscrollStrategy),
}
impl Autoscroll {
pub fn fit() -> Self {
Self::Strategy(AutoscrollStrategy::Fit)
}
pub fn newest() -> Self {
Self::Strategy(AutoscrollStrategy::Newest)
}
pub fn center() -> Self {
Self::Strategy(AutoscrollStrategy::Center)
}
}
#[derive(PartialEq, Eq, Default)]
pub enum AutoscrollStrategy {
Fit,
Newest,
#[default]
Center,
Top,
Bottom,
}
impl AutoscrollStrategy {
fn next(&self) -> Self {
match self {
AutoscrollStrategy::Center => AutoscrollStrategy::Top,
AutoscrollStrategy::Top => AutoscrollStrategy::Bottom,
_ => AutoscrollStrategy::Center,
}
}
}
impl Editor {
pub fn autoscroll_vertically(
&mut self,
viewport_height: Pixels,
line_height: Pixels,
cx: &mut ViewContext<Editor>,
) -> bool {
let visible_lines = f32::from(viewport_height / line_height);
let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
let mut scroll_position = self.scroll_manager.scroll_position(&display_map);
let max_scroll_top = if matches!(self.mode, EditorMode::AutoHeight { .. }) {
(display_map.max_point().row() as f32 - visible_lines + 1.).max(0.)
} else {
display_map.max_point().row() as f32
};
if scroll_position.y > max_scroll_top {
scroll_position.y = (max_scroll_top);
self.set_scroll_position(scroll_position, cx);
}
let Some((autoscroll, local)) = self.scroll_manager.autoscroll_request.take() else {
return false;
};
let mut target_top;
let mut target_bottom;
if let Some(highlighted_rows) = &self.highlighted_rows {
target_top = highlighted_rows.start as f32;
target_bottom = target_top + 1.;
} else {
let selections = self.selections.all::<Point>(cx);
target_top = selections
.first()
.unwrap()
.head()
.to_display_point(&display_map)
.row() as f32;
target_bottom = selections
.last()
.unwrap()
.head()
.to_display_point(&display_map)
.row() as f32
+ 1.0;
if autoscroll == Autoscroll::newest()
|| autoscroll == Autoscroll::fit() && target_bottom - target_top > visible_lines
{
let newest_selection_top = selections
.iter()
.max_by_key(|s| s.id)
.unwrap()
.head()
.to_display_point(&display_map)
.row() as f32;
target_top = newest_selection_top;
target_bottom = newest_selection_top + 1.;
}
}
let margin = if matches!(self.mode, EditorMode::AutoHeight { .. }) {
0.
} else {
((visible_lines - (target_bottom - target_top)) / 2.0).floor()
};
let strategy = match autoscroll {
Autoscroll::Strategy(strategy) => strategy,
Autoscroll::Next => {
let last_autoscroll = &self.scroll_manager.last_autoscroll;
if let Some(last_autoscroll) = last_autoscroll {
if self.scroll_manager.anchor.offset == last_autoscroll.0
&& target_top == last_autoscroll.1
&& target_bottom == last_autoscroll.2
{
last_autoscroll.3.next()
} else {
AutoscrollStrategy::default()
}
} else {
AutoscrollStrategy::default()
}
}
};
match strategy {
AutoscrollStrategy::Fit | AutoscrollStrategy::Newest => {
let margin = margin.min(self.scroll_manager.vertical_scroll_margin);
let target_top = (target_top - margin).max(0.0);
let target_bottom = target_bottom + margin;
let start_row = scroll_position.y;
let end_row = start_row + visible_lines;
let needs_scroll_up = target_top < start_row;
let needs_scroll_down = target_bottom >= end_row;
if needs_scroll_up && !needs_scroll_down {
scroll_position.y = (target_top);
self.set_scroll_position_internal(scroll_position, local, true, cx);
}
if !needs_scroll_up && needs_scroll_down {
scroll_position.y = (target_bottom - visible_lines);
self.set_scroll_position_internal(scroll_position, local, true, cx);
}
}
AutoscrollStrategy::Center => {
scroll_position.y = ((target_top - margin).max(0.0));
self.set_scroll_position_internal(scroll_position, local, true, cx);
}
AutoscrollStrategy::Top => {
scroll_position.y = ((target_top).max(0.0));
self.set_scroll_position_internal(scroll_position, local, true, cx);
}
AutoscrollStrategy::Bottom => {
scroll_position.y = ((target_bottom - visible_lines).max(0.0));
self.set_scroll_position_internal(scroll_position, local, true, cx);
}
}
self.scroll_manager.last_autoscroll = Some((
self.scroll_manager.anchor.offset,
target_top,
target_bottom,
strategy,
));
true
}
pub fn autoscroll_horizontally(
&mut self,
start_row: u32,
viewport_width: Pixels,
scroll_width: Pixels,
max_glyph_width: Pixels,
layouts: &[LineWithInvisibles],
cx: &mut ViewContext<Self>,
) -> bool {
let display_map = self.display_map.update(cx, |map, cx| map.snapshot(cx));
let selections = self.selections.all::<Point>(cx);
let mut target_left;
let mut target_right;
if self.highlighted_rows.is_some() {
target_left = px(0.);
target_right = px(0.);
} else {
target_left = px(f32::INFINITY);
target_right = px(0.);
for selection in selections {
let head = selection.head().to_display_point(&display_map);
if head.row() >= start_row && head.row() < start_row + layouts.len() as u32 {
let start_column = head.column().saturating_sub(3);
let end_column = cmp::min(display_map.line_len(head.row()), head.column() + 3);
target_left = target_left.min(
layouts[(head.row() - start_row) as usize]
.line
.x_for_index(start_column as usize),
);
target_right = target_right.max(
layouts[(head.row() - start_row) as usize]
.line
.x_for_index(end_column as usize)
+ max_glyph_width,
);
}
}
}
target_right = target_right.min(scroll_width);
if target_right - target_left > viewport_width {
return false;
}
let scroll_left = self.scroll_manager.anchor.offset.x * max_glyph_width;
let scroll_right = scroll_left + viewport_width;
if target_left < scroll_left {
self.scroll_manager.anchor.offset.x = (target_left / max_glyph_width).into();
true
} else if target_right > scroll_right {
self.scroll_manager.anchor.offset.x =
((target_right - viewport_width) / max_glyph_width).into();
true
} else {
false
}
}
pub fn request_autoscroll(&mut self, autoscroll: Autoscroll, cx: &mut ViewContext<Self>) {
self.scroll_manager.autoscroll_request = Some((autoscroll, true));
cx.notify();
}
pub(crate) fn request_autoscroll_remotely(
&mut self,
autoscroll: Autoscroll,
cx: &mut ViewContext<Self>,
) {
self.scroll_manager.autoscroll_request = Some((autoscroll, false));
cx.notify();
}
}