From 6eb853e3136dd320272bd67e2957774869c21e4b Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Wed, 10 May 2023 19:35:56 +0200
Subject: [PATCH] Reduce tearing when redrawing screen

---
 Cargo.toml      |  2 +-
 src/terminal.rs | 29 +++++++++++++++++++++--------
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index b1d625c..9641efb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ edition = "2021"
 
 [dependencies]
 async-trait = "0.1.64"
-crossterm = "0.26.0"
+crossterm = "0.26.1"
 unicode-linebreak = "0.1.4"
 unicode-segmentation = "1.10.1"
 unicode-width = "0.1.10"
diff --git a/src/terminal.rs b/src/terminal.rs
index e4352f1..db7dcdd 100644
--- a/src/terminal.rs
+++ b/src/terminal.rs
@@ -9,7 +9,10 @@ use crossterm::event::{
     PopKeyboardEnhancementFlags, PushKeyboardEnhancementFlags,
 };
 use crossterm::style::{PrintStyledContent, StyledContent};
-use crossterm::terminal::{Clear, ClearType, EnterAlternateScreen, LeaveAlternateScreen};
+use crossterm::terminal::{
+    BeginSynchronizedUpdate, Clear, ClearType, EndSynchronizedUpdate, EnterAlternateScreen,
+    LeaveAlternateScreen,
+};
 use crossterm::{ExecutableCommand, QueueableCommand};
 
 use crate::buffer::Buffer;
@@ -198,14 +201,11 @@ impl Terminal {
     /// After calling this function, the frame returned by [`Self::frame`] will
     /// be empty again and have no cursor position.
     pub fn present(&mut self) -> io::Result<()> {
-        if self.full_redraw {
-            self.out.queue(Clear(ClearType::All))?;
-            self.prev_frame_buffer.reset(); // Because the screen is now empty
-            self.full_redraw = false;
-        }
+        self.out.queue(BeginSynchronizedUpdate)?;
+        let result = self.draw_to_screen();
+        self.out.queue(EndSynchronizedUpdate)?;
+        result?;
 
-        self.draw_differences()?;
-        self.update_cursor()?;
         self.out.flush()?;
 
         mem::swap(&mut self.prev_frame_buffer, &mut self.frame.buffer);
@@ -244,6 +244,19 @@ impl Terminal {
         Ok(())
     }
 
+    fn draw_to_screen(&mut self) -> io::Result<()> {
+        if self.full_redraw {
+            self.out.queue(Clear(ClearType::All))?;
+            self.prev_frame_buffer.reset(); // Because the screen is now empty
+            self.full_redraw = false;
+        }
+
+        self.draw_differences()?;
+        self.update_cursor()?;
+
+        Ok(())
+    }
+
     fn draw_differences(&mut self) -> io::Result<()> {
         for (x, y, cell) in self.frame.buffer.cells() {
             if self.prev_frame_buffer.at(x, y) == cell {