cessen/led
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Simplified the screen buffer writing.

Browse Source 
Turns out the main reason it was so slow was because stdout isn't
buffered in Rust by default.  That actually makes a lot of sense,
but I'd forgotten.

Wrapping it in a BufWriter solves the performance issues much more
gracefully.
This commit is contained in:
Nathan Vegdahl 2018-01-01 03:10:32 -08:00
parent 1f62eb32a0
commit 2591aef6d4
1 changed files with 14 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
src/term_ui/screen.rs
View File

@ -1,7 +1,7 @@
use std;
use std::cell::RefCell;
use std::io;
use std::io::Write;
use std::io::{BufWriter, Write};
use super::smallstring::SmallString;
use unicode_width::UnicodeWidthStr;
@ -12,7 +12,7 @@ use termion::color;
use termion::raw::{IntoRawMode, RawTerminal};
pub(crate) struct Screen {
out: RefCell<AlternateScreen<RawTerminal<io::Stdout>>>,
out: RefCell<AlternateScreen<RawTerminal<BufWriter<io::Stdout>>>>,
buf: RefCell<Vec<Option<(Style, SmallString)>>>,
w: usize,
h: usize,
@ -25,7 +25,11 @@ impl Screen {
.take(w as usize * h as usize)
.collect();
Screen {
out: RefCell::new(AlternateScreen::from(io::stdout().into_raw_mode().unwrap())),
out: RefCell::new(AlternateScreen::from(
BufWriter::with_capacity(1 << 14, io::stdout())
.into_raw_mode()
.unwrap(),
)),
buf: RefCell::new(buf),
w: w as usize,
h: h as usize,
@ -56,39 +60,31 @@ impl Screen {
}
pub(crate) fn present(&self) {
let mut out = self.out.borrow_mut();
let buf = self.buf.borrow();
// Double the minimum needed space, because of formatting characters and such.
let mut tmp_string = String::with_capacity(self.w * self.h * 2);
tmp_string.push_str(&format!("{}", termion::cursor::Goto(1, 1)));
let mut last_style = Style(Color::Black, Color::Black);
write!(out, "{}", last_style).unwrap();
// Write everything to the tmp_string first.
for y in 0..self.h {
let mut x = 0;
let mut last_style = Style(Color::Black, Color::Black);
tmp_string.push_str(&format!("{}", last_style));
write!(out, "{}", termion::cursor::Goto(1, y as u16 + 2)).unwrap();
while x < self.w {
if let Some((style, ref text)) = buf[y * self.w + x] {
if style != last_style {
tmp_string.push_str(&format!("{}", style));
write!(out, "{}", style).unwrap();
last_style = style;
}
tmp_string.push_str(text);
write!(out, "{}", text).unwrap();
x += 1;
} else {
x += 1;
}
}
tmp_string.push_str(&format!("{}", termion::cursor::Goto(1, y as u16 + 2)));
}
// Write tmp_string to the screen all at once.
write!(
self.out.borrow_mut(),
"{}{}",
termion::cursor::Goto(0, 0),
tmp_string,
).unwrap();
// Make sure everything is written out
self.out.borrow_mut().flush().unwrap();
}