From a69caff450ff8201e16d0a0b4617114e03ed3c97 Mon Sep 17 00:00:00 2001
From: CossonLeo <20379044+cossonleo@users.noreply.github.com>
Date: Tue, 9 Nov 2021 10:11:45 +0800
Subject: [PATCH] search_impl will only align cursor center when it isn't in
 view (#959)

---
 helix-term/src/commands.rs | 22 +++++++++++++++++---
 helix-view/src/view.rs     | 41 ++++++++++++++++++++++++++++++--------
 2 files changed, 52 insertions(+), 11 deletions(-)

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 245fbe4ee..42163b8e0 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -1175,6 +1175,7 @@ fn search_impl(
     regex: &Regex,
     movement: Movement,
     direction: Direction,
+    scrolloff: usize,
 ) {
     let text = doc.text().slice(..);
     let selection = doc.selection(view.id);
@@ -1233,7 +1234,11 @@ fn search_impl(
         };
 
         doc.set_selection(view.id, selection);
-        align_view(doc, view, Align::Center);
+        if view.is_cursor_in_view(doc, 0) {
+            view.ensure_cursor_in_view(doc, scrolloff);
+        } else {
+            align_view(doc, view, Align::Center)
+        }
     };
 }
 
@@ -1257,6 +1262,8 @@ fn rsearch(cx: &mut Context) {
 // TODO: use one function for search vs extend
 fn searcher(cx: &mut Context, direction: Direction) {
     let reg = cx.register.unwrap_or('/');
+    let scrolloff = cx.editor.config.scrolloff;
+
     let (_, doc) = current!(cx.editor);
 
     // TODO: could probably share with select_on_matches?
@@ -1281,7 +1288,15 @@ fn searcher(cx: &mut Context, direction: Direction) {
             if event != PromptEvent::Update {
                 return;
             }
-            search_impl(doc, view, &contents, &regex, Movement::Move, direction);
+            search_impl(
+                doc,
+                view,
+                &contents,
+                &regex,
+                Movement::Move,
+                direction,
+                scrolloff,
+            );
         },
     );
 
@@ -1289,6 +1304,7 @@ fn searcher(cx: &mut Context, direction: Direction) {
 }
 
 fn search_next_or_prev_impl(cx: &mut Context, movement: Movement, direction: Direction) {
+    let scrolloff = cx.editor.config.scrolloff;
     let (view, doc) = current!(cx.editor);
     let registers = &cx.editor.registers;
     if let Some(query) = registers.read('/') {
@@ -1303,7 +1319,7 @@ fn search_next_or_prev_impl(cx: &mut Context, movement: Movement, direction: Dir
             .case_insensitive(case_insensitive)
             .build()
         {
-            search_impl(doc, view, &contents, &regex, movement, direction);
+            search_impl(doc, view, &contents, &regex, movement, direction, scrolloff);
         } else {
             // get around warning `mutable_borrow_reservation_conflict`
             // which will be a hard error in the future
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index 11f301550..6a624ded2 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -85,7 +85,12 @@ impl View {
         self.area.clip_left(OFFSET).clip_bottom(1) // -1 for statusline
     }
 
-    pub fn ensure_cursor_in_view(&mut self, doc: &Document, scrolloff: usize) {
+    //
+    pub fn offset_coords_to_in_view(
+        &self,
+        doc: &Document,
+        scrolloff: usize,
+    ) -> Option<(usize, usize)> {
         let cursor = doc
             .selection(self.id)
             .primary()
@@ -104,23 +109,43 @@ impl View {
 
         let last_col = self.offset.col + inner_area.width.saturating_sub(1) as usize;
 
-        if line > last_line.saturating_sub(scrolloff) {
+        let row = if line > last_line.saturating_sub(scrolloff) {
             // scroll down
-            self.offset.row += line - (last_line.saturating_sub(scrolloff));
+            self.offset.row + line - (last_line.saturating_sub(scrolloff))
         } else if line < self.offset.row + scrolloff {
             // scroll up
-            self.offset.row = line.saturating_sub(scrolloff);
-        }
+            line.saturating_sub(scrolloff)
+        } else {
+            self.offset.row
+        };
 
-        if col > last_col.saturating_sub(scrolloff) {
+        let col = if col > last_col.saturating_sub(scrolloff) {
             // scroll right
-            self.offset.col += col - (last_col.saturating_sub(scrolloff));
+            self.offset.col + col - (last_col.saturating_sub(scrolloff))
         } else if col < self.offset.col + scrolloff {
             // scroll left
-            self.offset.col = col.saturating_sub(scrolloff);
+            col.saturating_sub(scrolloff)
+        } else {
+            self.offset.col
+        };
+        if row == self.offset.row && col == self.offset.col {
+            None
+        } else {
+            Some((row, col))
         }
     }
 
+    pub fn ensure_cursor_in_view(&mut self, doc: &Document, scrolloff: usize) {
+        if let Some((row, col)) = self.offset_coords_to_in_view(doc, scrolloff) {
+            self.offset.row = row;
+            self.offset.col = col;
+        }
+    }
+
+    pub fn is_cursor_in_view(&mut self, doc: &Document, scrolloff: usize) -> bool {
+        self.offset_coords_to_in_view(doc, scrolloff).is_none()
+    }
+
     /// Calculates the last visible line on screen
     #[inline]
     pub fn last_line(&self, doc: &Document) -> usize {