Only show 1000 lines of history in terminal

src/emulator.rs

@@ -47,7 +47,7 @@ impl SimId {
         match index {
             0 => Some(Self::Player1),
             1 => Some(Self::Player2),
-            _ => None
+            _ => None,
         }
     }
 }
@@ -239,7 +239,10 @@ impl Emulator {
         while self.sims.len() <= index {
             let new_index = self.sims.len();
             self.sims.push(Sim::new());
-            if self.stdouts.contains_key(&SimId::from_index(new_index).unwrap()) {
+            if self
+                .stdouts
+                .contains_key(&SimId::from_index(new_index).unwrap())
+            {
                 self.sims[new_index].watch_stdout(true);
             }
             self.sim_state[new_index].store(SimState::NoGame, Ordering::Release);

src/window/terminal.rs

@@ -1,4 +1,4 @@
-use std::sync::mpsc;
+use std::{collections::VecDeque, sync::mpsc};
 
 use egui::{
     Align, CentralPanel, Context, FontFamily, Label, RichText, ScrollArea, ViewportBuilder,
@@ -9,20 +9,24 @@ use crate::emulator::{EmulatorClient, EmulatorCommand, SimId};
 
 use super::AppWindow;
 
+const SCROLLBACK: usize = 1000;
+
 pub struct TerminalWindow {
     sim_id: SimId,
     receiver: mpsc::Receiver<String>,
-    text: String,
+    lines: VecDeque<String>,
 }
 
 impl TerminalWindow {
     pub fn new(sim_id: SimId, client: &EmulatorClient) -> Self {
         let (sender, receiver) = mpsc::channel();
         client.send_command(EmulatorCommand::WatchStdout(sim_id, sender));
+        let mut lines = VecDeque::new();
+        lines.push_back(String::new());
         Self {
             sim_id,
             receiver,
-            text: String::new(),
+            lines,
         }
     }
 }
@@ -44,17 +48,31 @@ impl AppWindow for TerminalWindow {
 
     fn show(&mut self, ctx: &Context) {
         if let Ok(text) = self.receiver.try_recv() {
-            self.text.push_str(&text);
+            let mut rest = text.as_str();
+            while let Some(index) = rest.find('\n') {
+                let (line, lines) = rest.split_at(index);
+                let current = self.lines.back_mut().unwrap();
+                current.push_str(line);
+                self.lines.push_back(String::new());
+                if self.lines.len() > SCROLLBACK {
+                    self.lines.pop_front();
+                }
+                rest = &lines[1..];
+            }
+            self.lines.back_mut().unwrap().push_str(rest);
         }
         CentralPanel::default().show(ctx, |ui| {
             ScrollArea::vertical()
                 .stick_to_bottom(true)
                 .auto_shrink([false, false])
+                .animated(false)
                 .show(ui, |ui| {
-                    let label = Label::new(RichText::new(&self.text).family(FontFamily::Monospace))
+                    for line in &self.lines {
+                        let label = Label::new(RichText::new(line).family(FontFamily::Monospace))
                             .halign(Align::LEFT)
                             .wrap();
                         ui.add(label);
+                    }
                 });
         });
     }