From 58cae8f2edf44e6bf0721543c61edb57bdf7d776 Mon Sep 17 00:00:00 2001
From: Richard Steinmetz <richard@steinmetz.cloud>
Date: Wed, 31 Mar 2021 21:11:16 +0200
Subject: Keep viewport in place during resize

Fixes #4879.

Co-authored-by: Christian Duerr <contact@christianduerr.com>
---
 alacritty_terminal/src/grid/resize.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'alacritty_terminal/src/grid/resize.rs')

diff --git a/alacritty_terminal/src/grid/resize.rs b/alacritty_terminal/src/grid/resize.rs
index eb8bef0c..10bc51f9 100644
--- a/alacritty_terminal/src/grid/resize.rs
+++ b/alacritty_terminal/src/grid/resize.rs
@@ -187,7 +187,7 @@ impl<T: GridCell + Default + PartialEq + Clone> Grid<T> {
 
                 cursor_line_delta += line_delta.0 as usize;
             } else if row.is_clear() {
-                if i + reversed.len() >= self.lines {
+                if i <= self.display_offset {
                     // Since we removed a line, rotate down the viewport.
                     self.display_offset = self.display_offset.saturating_sub(1);
                 }
@@ -354,6 +354,11 @@ impl<T: GridCell + Default + PartialEq + Clone> Grid<T> {
                         wrapped.resize_with(columns, T::default);
                     }
                     row = Row::from_vec(wrapped, occ);
+
+                    if i <= self.display_offset {
+                        // Since we added a new line, rotate up the viewport.
+                        self.display_offset += 1;
+                    }
                 }
             }
         }
-- 
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