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ui: menu: Adjust scroll via required_size area caching.

pull/8/head
Blaž Hrastnik 2021-03-08 17:13:45 +09:00
parent 5ea610c41d
commit ddcf5156c0
1 changed files with 28 additions and 17 deletions
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45
helix-term/src/ui/menu.rs
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@ -8,7 +8,6 @@ use tui::{
}; };
use std::borrow::Cow; use std::borrow::Cow;
use std::cell::Cell;
use helix_core::Position; use helix_core::Position;
use helix_view::Editor; use helix_view::Editor;
@ -24,7 +23,8 @@ pub struct Menu<T> {
format_fn: Box<dyn Fn(&T) -> Cow<str>>, format_fn: Box<dyn Fn(&T) -> Cow<str>>,
callback_fn: Box<dyn Fn(&mut Editor, Option<&T>, MenuEvent)>, callback_fn: Box<dyn Fn(&mut Editor, Option<&T>, MenuEvent)>,
scroll: Cell<usize>, scroll: usize,
size: (u16, u16),
} }
impl<T> Menu<T> { impl<T> Menu<T> {
@ -40,7 +40,8 @@ impl<T> Menu<T> {
cursor: None, cursor: None,
format_fn: Box::new(format_fn), format_fn: Box::new(format_fn),
callback_fn: Box::new(callback_fn), callback_fn: Box::new(callback_fn),
scroll: Cell::new(0), scroll: 0,
size: (0, 0),
} }
} }
@ -48,11 +49,28 @@ impl<T> Menu<T> {
// TODO: wrap around to end // TODO: wrap around to end
let pos = self.cursor.map(|i| i.saturating_sub(1)).unwrap_or(0) % self.options.len(); let pos = self.cursor.map(|i| i.saturating_sub(1)).unwrap_or(0) % self.options.len();
self.cursor = Some(pos); self.cursor = Some(pos);
self.adjust_scroll();
} }
pub fn move_down(&mut self) { pub fn move_down(&mut self) {
let pos = self.cursor.map(|i| i + 1).unwrap_or(0) % self.options.len(); let pos = self.cursor.map(|i| i + 1).unwrap_or(0) % self.options.len();
self.cursor = Some(pos); self.cursor = Some(pos);
self.adjust_scroll();
}
fn adjust_scroll(&mut self) {
let win_height = self.size.1 as usize;
if let Some(cursor) = self.cursor {
let mut scroll = self.scroll;
if cursor > (win_height + scroll).saturating_sub(1) {
// scroll down
scroll += cursor - (win_height + scroll).saturating_sub(1)
} else if cursor < scroll {
// scroll up
scroll = cursor
}
self.scroll = scroll;
}
} }
pub fn selection(&self) -> Option<&T> { pub fn selection(&self) -> Option<&T> {
@ -156,30 +174,23 @@ impl<T> Component for Menu<T> {
let height = std::cmp::min(self.options.len(), MAX); let height = std::cmp::min(self.options.len(), MAX);
let height = std::cmp::min(height, viewport.1 as usize); let height = std::cmp::min(height, viewport.1 as usize);
Some((width as u16, height as u16)) self.size = (width as u16, height as u16);
// adjust scroll offsets if size changed
self.adjust_scroll();
Some(self.size)
} }
fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) { fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) {
let style = Style::default().fg(Color::Rgb(164, 160, 232)); // lavender let style = Style::default().fg(Color::Rgb(164, 160, 232)); // lavender
let selected = Style::default().fg(Color::Rgb(255, 255, 255)); let selected = Style::default().fg(Color::Rgb(255, 255, 255));
// TODO: instead of a cell, all these numbers should be precomputed in handle_event + init let scroll = self.scroll;
let mut scroll = self.scroll.get();
let len = self.options.len(); let len = self.options.len();
let win_height = area.height as usize; let win_height = area.height as usize;
if let Some(cursor) = self.cursor {
if cursor > (win_height + scroll).saturating_sub(1) {
// scroll down
scroll += cursor - (win_height + scroll).saturating_sub(1)
} else if cursor < scroll {
// scroll up
scroll = cursor
}
self.scroll.set(scroll);
}
fn div_ceil(a: usize, b: usize) -> usize { fn div_ceil(a: usize, b: usize) -> usize {
(a + b - 1) / a (a + b - 1) / a
} }