use std::fmt::Write;
use unicode_width::UnicodeWidthStr;
use crate::primitives::termtui::{
protocol::CursorStyle,
vt100::{
attrs::Attrs,
grid::{Grid, Pos},
Cell, Size,
},
};
pub struct ScreenDiffer {
cells: Vec<Cell>,
brush: Attrs,
pos: Pos,
cursor_pos: Option<Pos>,
cursor_style: CursorStyle,
}
pub trait BufferView {
fn size(&self) -> Size;
fn get_cell(&self, pos: Pos) -> Option<&Cell>;
fn get_cursor_pos(&self) -> Option<Pos>;
fn get_cursor_style(&self) -> CursorStyle;
}
impl ScreenDiffer {
pub fn new() -> Self {
Self {
cells: Vec::new(),
brush: Attrs::default(),
pos: Pos { row: 0, col: 0 },
cursor_pos: Some(Pos { col: 0, row: 0 }),
cursor_style: CursorStyle::default(),
}
}
pub fn diff<V: BufferView, W: Write>(&mut self, w: &mut W, view: &V) -> std::fmt::Result {
let prev = &mut self.cells;
let brush = &mut self.brush;
let size = view.size();
let mut full_rerender = false;
if (size.height * size.width) as usize != prev.len() {
full_rerender = true;
prev.resize((size.height * size.width) as usize, Cell::default());
}
for y in 0..size.height {
for x in 0..size.width {
let offset = (size.width * y + x) as usize;
let cell = view
.get_cell(Pos { col: x, row: y })
.cloned()
.unwrap_or_default();
let mut sep = {
let mut first = true;
move |w: &mut W| {
if first {
first = false;
Ok(())
} else {
write!(w, ";")
}
}
};
if full_rerender || cell != prev[offset] {
let attrs = *cell.attrs();
if *brush != attrs {
write!(w, "\x1b[")?;
if brush.fgcolor != attrs.fgcolor {
sep(w)?;
match attrs.fgcolor {
super::Color::Default => write!(w, "39")?,
super::Color::Idx(idx) => write!(w, "38;5;{}", idx)?,
super::Color::Rgb(r, g, b) => write!(w, "38;2;{r};{g};{b}")?,
}
}
if brush.bgcolor != attrs.bgcolor {
sep(w)?;
match attrs.bgcolor {
super::Color::Default => write!(w, "49")?,
super::Color::Idx(idx) => write!(w, "48;5;{}", idx)?,
super::Color::Rgb(r, g, b) => write!(w, "48;2;{r};{g};{b}")?,
}
}
if brush.bold() != attrs.bold() {
sep(w)?;
let value = if attrs.bold() { 1 } else { 22 };
write!(w, "{value}")?;
}
if brush.italic() != attrs.italic() {
sep(w)?;
let value = if attrs.italic() { 3 } else { 23 };
write!(w, "{value}")?;
}
if brush.underline() != attrs.underline() {
sep(w)?;
let value = if attrs.italic() { 4 } else { 24 };
write!(w, "{value}")?;
}
if brush.inverse() != attrs.inverse() {
sep(w)?;
let value = if attrs.inverse() { 7 } else { 27 };
write!(w, "{value}")?;
}
write!(w, "m")?;
*brush = attrs;
}
let pos = Pos { row: y, col: x };
if self.pos != pos {
write!(w, "\x1b[{};{}H", pos.row + 1, pos.col + 1)?;
self.pos = pos;
}
let c = if cell.width() > 0 {
cell.contents()
} else {
" "
};
write!(w, "{}", c)?;
self.pos.col = (size.width - 1).min(self.pos.col + c.width() as u16);
prev[offset] = cell;
}
}
}
if self.cursor_pos.is_some() != view.get_cursor_pos().is_some() {
if view.get_cursor_pos().is_some() {
write!(w, "\x1b[?25h")?;
} else {
write!(w, "\x1b[?25l")?;
}
}
if let Some(pos) = view.get_cursor_pos() {
if self.pos != pos {
write!(w, "\x1b[{};{}H", pos.row + 1, pos.col + 1)?;
}
self.pos = pos;
}
self.cursor_pos = view.get_cursor_pos();
if self.cursor_style != view.get_cursor_style() {
let cmd = match view.get_cursor_style() {
CursorStyle::Default => 0,
CursorStyle::BlinkingBlock => 1,
CursorStyle::SteadyBlock => 2,
CursorStyle::BlinkingUnderline => 3,
CursorStyle::SteadyUnderline => 4,
CursorStyle::BlinkingBar => 5,
CursorStyle::SteadyBar => 6,
};
write!(w, "\x1b[{} q", cmd)?;
self.cursor_style = view.get_cursor_style();
}
Ok(())
}
}
impl BufferView for Vec<Vec<Cell>> {
fn size(&self) -> Size {
Size {
height: self.len() as u16,
width: self.get(0).map_or(0, |row| row.len() as u16),
}
}
fn get_cell(&self, pos: Pos) -> Option<&Cell> {
self.get(pos.row as usize)
.map(|row| row.get(pos.col as usize))
.flatten()
}
fn get_cursor_pos(&self) -> Option<Pos> {
None
}
fn get_cursor_style(&self) -> CursorStyle {
CursorStyle::Default
}
}
impl BufferView for Grid {
fn size(&self) -> Size {
self.size()
}
fn get_cell(&self, pos: Pos) -> Option<&Cell> {
self.visible_cell(pos)
}
fn get_cursor_pos(&self) -> Option<Pos> {
self.cursor_pos
}
fn get_cursor_style(&self) -> CursorStyle {
self.cursor_style
}
}
#[cfg(test)]
mod tests {
use crate::primitives::termtui::vt100::Color;
use super::*;
#[test]
fn basic() {
let attrs = Attrs {
fgcolor: Color::Idx(4),
..Default::default()
};
let mut differ = ScreenDiffer::new();
let mut out = String::new();
let screen = vec![vec![
Cell::new("1"),
Cell::new("2"),
Cell::new("3").with_attrs(attrs),
Cell::new("4").with_attrs(attrs),
Cell::new("5"),
]];
differ.diff(&mut out, &screen).unwrap();
assert_eq!("12\x1b[38;5;4m34\x1b[39m5", out);
let screen = vec![vec![
Cell::new("1"),
Cell::new("_"),
Cell::new("3"),
Cell::new("4").with_attrs(attrs),
Cell::new("5"),
]];
out.clear();
differ.diff(&mut out, &screen).unwrap();
assert_eq!("\x1b[1;2H_3", out);
}
}