perf: fast display (row runs, bulk fills, pixel scroll), terminal draws changed cells only + scrolls pixels, print! batched (was IPC per fmt fragment), snake sleeps on timer

crates/servers/terminal-server/src/lib.rs

@@ -15,7 +15,7 @@ use libkos::input::{InputEvent, Key};
 use libkos::syscall;
 use types::badge::Badge;
 use types::bounded::CapSlot;
-use types::display::{Color, ScreenCoord};
+use types::display::{Color, Dimension, ScreenCoord};
 use types::terminal::{KEYS_BIT, TIMER_BIT};
 
 /// Where init put them (its manifest: own endpoint, then `uses`).
@@ -33,6 +33,8 @@ struct Screen {
     /// `KEYS_BIT`, the flush timer with `TIMER_BIT`.
     notify: CapSlot,
     timer: CapSlot,
+    /// The screen's height, all of which scrolls.
+    height: Dimension,
 }
 
 /// A key as the line editor wants it, if it is one.
@@ -65,6 +67,11 @@ impl server::Console for Screen {
         display::flush(DISPLAY);
     }
 
+    fn scroll(&mut self, rows: usize) {
+        let by = Dimension::new(u16::try_from(rows * CELL_HEIGHT).unwrap_or(u16::MAX));
+        display::scroll(DISPLAY, ScreenCoord::new(0), self.height, by, BG);
+    }
+
     fn flush_later(&mut self) {
         let at = syscall::get_time().raw() + FLUSH_DELAY;
         let _ = syscall::set_timer(self.timer, types::time::Ticks::from_raw(at));
@@ -116,6 +123,6 @@ pub fn run() -> ! {
     display::clear(DISPLAY, BG);
     let cols = w.raw() as usize / CELL_WIDTH;
     let rows = h.raw() as usize / CELL_HEIGHT;
-    let mut srv = server::TerminalServer::new(Screen { notify, timer }, cols, rows);
+    let mut srv = server::TerminalServer::new(Screen { notify, timer, height: h }, cols, rows);
     server_framework::serve(&mut srv, EP)
 }