From de2a82625b639ee461e19d33f105ba6356665f2a Mon Sep 17 00:00:00 2001
From: Joe Lim <50560759+joelim-work@users.noreply.github.com>
Date: Sat, 18 Nov 2023 23:35:16 +1100
Subject: [PATCH] Fix `low`/`high` crash for big `scrolloff` values

---
 nav.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/nav.go b/nav.go
index f748619c..162a5bd0 100644
--- a/nav.go
+++ b/nav.go
@@ -1144,7 +1144,7 @@ func (nav *nav) high() bool {
 
 	old := dir.ind
 	beg := max(dir.ind-dir.pos, 0)
-	offs := gOpts.scrolloff
+	offs := min(nav.height/2, gOpts.scrolloff)
 	if beg == 0 {
 		offs = 0
 	}
@@ -1175,7 +1175,14 @@ func (nav *nav) low() bool {
 	old := dir.ind
 	beg := max(dir.ind-dir.pos, 0)
 	end := min(beg+nav.height, len(dir.files))
-	offs := gOpts.scrolloff
+
+	offs := min(nav.height/2, gOpts.scrolloff)
+	// use a smaller value for half when the height is even and scrolloff is
+	// maxed in order to stay at the same row when using both high and low
+	if nav.height%2 == 0 {
+		offs = min(nav.height/2-1, gOpts.scrolloff)
+	}
+
 	if end == len(dir.files) {
 		offs = 0
 	}