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use crate::{backend::Backend, buffer::Cell};
use crossterm::{
cursor::{CursorShape, Hide, MoveTo, SetCursorShape, Show},
execute, queue,
style::{
Attribute as CAttribute, Color as CColor, Print, SetAttribute, SetBackgroundColor,
SetForegroundColor, SetUnderlineColor,
},
terminal::{self, Clear, ClearType},
};
use helix_view::graphics::{Color, CursorKind, Modifier, Rect, UnderlineStyle};
use std::io::{self, Write};
fn vte_version() -> Option<usize> {
std::env::var("VTE_VERSION").ok()?.parse().ok()
}
/// Describes terminal capabilities like extended underline, truecolor, etc.
#[derive(Copy, Clone, Debug, Default)]
struct Capabilities {
/// Support for undercurled, underdashed, etc.
has_extended_underlines: bool,
}
impl Capabilities {
/// Detect capabilities from the terminfo database located based
/// on the $TERM environment variable. If detection fails, returns
/// a default value where no capability is supported.
pub fn from_env_or_default() -> Self {
match termini::TermInfo::from_env() {
Err(_) => Capabilities::default(),
Ok(t) => Capabilities {
// Smulx, VTE: https://unix.stackexchange.com/a/696253/246284
// Su (used by kitty): https://sw.kovidgoyal.net/kitty/underlines
has_extended_underlines: t.extended_cap("Smulx").is_some()
|| t.extended_cap("Su").is_some()
|| vte_version() >= Some(5102),
},
}
}
}
pub struct CrosstermBackend<W: Write> {
buffer: W,
capabilities: Capabilities,
}
impl<W> CrosstermBackend<W>
where
W: Write,
{
pub fn new(buffer: W) -> CrosstermBackend<W> {
CrosstermBackend {
buffer,
capabilities: Capabilities::from_env_or_default(),
}
}
}
impl<W> Write for CrosstermBackend<W>
where
W: Write,
{
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.buffer.write(buf)
}
fn flush(&mut self) -> io::Result<()> {
self.buffer.flush()
}
}
impl<W> Backend for CrosstermBackend<W>
where
W: Write,
{
fn draw<'a, I>(&mut self, content: I) -> io::Result<()>
where
I: Iterator<Item = (u16, u16, &'a Cell)>,
{
let mut fg = Color::Reset;
let mut bg = Color::Reset;
let mut underline_color = Color::Reset;
let mut underline_style = UnderlineStyle::Reset;
let mut modifier = Modifier::empty();
let mut last_pos: Option<(u16, u16)> = None;
for (x, y, cell) in content {
// Move the cursor if the previous location was not (x - 1, y)
if !matches!(last_pos, Some(p) if x == p.0 + 1 && y == p.1) {
map_error(queue!(self.buffer, MoveTo(x, y)))?;
}
last_pos = Some((x, y));
if cell.modifier != modifier {
let diff = ModifierDiff {
from: modifier,
to: cell.modifier,
};
diff.queue(&mut self.buffer)?;
modifier = cell.modifier;
}
if cell.fg != fg {
let color = CColor::from(cell.fg);
map_error(queue!(self.buffer, SetForegroundColor(color)))?;
fg = cell.fg;
}
if cell.bg != bg {
let color = CColor::from(cell.bg);
map_error(queue!(self.buffer, SetBackgroundColor(color)))?;
bg = cell.bg;
}
if cell.underline_color != underline_color {
let color = CColor::from(cell.underline_color);
map_error(queue!(self.buffer, SetUnderlineColor(color)))?;
underline_color = cell.underline_color;
}
let mut new_underline_style = cell.underline_style;
if !self.capabilities.has_extended_underlines {
match new_underline_style {
UnderlineStyle::Reset => (),
_ => new_underline_style = UnderlineStyle::Line,
}
}
if new_underline_style != underline_style {
let attr = CAttribute::from(cell.underline_style);
map_error(queue!(self.buffer, SetAttribute(attr)))?;
underline_style = new_underline_style;
}
map_error(queue!(self.buffer, Print(&cell.symbol)))?;
}
map_error(queue!(
self.buffer,
SetUnderlineColor(CColor::Reset),
SetForegroundColor(CColor::Reset),
SetBackgroundColor(CColor::Reset),
SetAttribute(CAttribute::Reset)
))
}
fn hide_cursor(&mut self) -> io::Result<()> {
map_error(execute!(self.buffer, Hide))
}
fn show_cursor(&mut self, kind: CursorKind) -> io::Result<()> {
let shape = match kind {
CursorKind::Block => CursorShape::Block,
CursorKind::Bar => CursorShape::Line,
CursorKind::Underline => CursorShape::UnderScore,
CursorKind::Hidden => unreachable!(),
};
map_error(execute!(self.buffer, Show, SetCursorShape(shape)))
}
fn get_cursor(&mut self) -> io::Result<(u16, u16)> {
crossterm::cursor::position()
.map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))
}
fn set_cursor(&mut self, x: u16, y: u16) -> io::Result<()> {
map_error(execute!(self.buffer, MoveTo(x, y)))
}
fn clear(&mut self) -> io::Result<()> {
map_error(execute!(self.buffer, Clear(ClearType::All)))
}
fn size(&self) -> io::Result<Rect> {
let (width, height) =
terminal::size().map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))?;
Ok(Rect::new(0, 0, width, height))
}
fn flush(&mut self) -> io::Result<()> {
self.buffer.flush()
}
}
fn map_error(error: crossterm::Result<()>) -> io::Result<()> {
error.map_err(|e| io::Error::new(io::ErrorKind::Other, e.to_string()))
}
#[derive(Debug)]
struct ModifierDiff {
pub from: Modifier,
pub to: Modifier,
}
impl ModifierDiff {
fn queue<W>(&self, mut w: W) -> io::Result<()>
where
W: io::Write,
{
//use crossterm::Attribute;
let removed = self.from - self.to;
if removed.contains(Modifier::REVERSED) {
map_error(queue!(w, SetAttribute(CAttribute::NoReverse)))?;
}
if removed.contains(Modifier::BOLD) {
map_error(queue!(w, SetAttribute(CAttribute::NormalIntensity)))?;
if self.to.contains(Modifier::DIM) {
map_error(queue!(w, SetAttribute(CAttribute::Dim)))?;
}
}
if removed.contains(Modifier::ITALIC) {
map_error(queue!(w, SetAttribute(CAttribute::NoItalic)))?;
}
if removed.contains(Modifier::DIM) {
map_error(queue!(w, SetAttribute(CAttribute::NormalIntensity)))?;
}
if removed.contains(Modifier::CROSSED_OUT) {
map_error(queue!(w, SetAttribute(CAttribute::NotCrossedOut)))?;
}
if removed.contains(Modifier::SLOW_BLINK) || removed.contains(Modifier::RAPID_BLINK) {
map_error(queue!(w, SetAttribute(CAttribute::NoBlink)))?;
}
let added = self.to - self.from;
if added.contains(Modifier::REVERSED) {
map_error(queue!(w, SetAttribute(CAttribute::Reverse)))?;
}
if added.contains(Modifier::BOLD) {
map_error(queue!(w, SetAttribute(CAttribute::Bold)))?;
}
if added.contains(Modifier::ITALIC) {
map_error(queue!(w, SetAttribute(CAttribute::Italic)))?;
}
if added.contains(Modifier::DIM) {
map_error(queue!(w, SetAttribute(CAttribute::Dim)))?;
}
if added.contains(Modifier::CROSSED_OUT) {
map_error(queue!(w, SetAttribute(CAttribute::CrossedOut)))?;
}
if added.contains(Modifier::SLOW_BLINK) {
map_error(queue!(w, SetAttribute(CAttribute::SlowBlink)))?;
}
if added.contains(Modifier::RAPID_BLINK) {
map_error(queue!(w, SetAttribute(CAttribute::RapidBlink)))?;
}
Ok(())
}
}
|
