fix scroll adjustement when using the arrow keysv0.11.6

(when there's a scrollbar)

Fix #112

2 files changed, 19 insertions, 7 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a45f05..e6f9918 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,10 @@
 ### master
-- backspace was previously bind to back if not consumed by input. This is removed
-- fix unsignificative events interpreted as previous event repetition
-- fix wrong background applied below sizes
+- backspace was previously bound to :back if not consumed by input. This is removed
+- fix unsignificative event interpreted as previous event repetition
+- fix wrong background applied on sizes in tree display
 - allow env vars used in verb execution to contain parameters (fix #114)
+- allow the use of arrow keys as triggers for verbs (fix #121)
+- fix scroll adjustement when using the arrow keys (when there's a scrollbar) (fix #112)
 
 <a name="v0.11.5"></a>
 ### v0.11.5 - 2020-01-10
diff --git a/src/flat_tree.rs b/src/flat_tree.rs
index 8822226..08fdceb 100644
--- a/src/flat_tree.rs
+++ b/src/flat_tree.rs
@@ -287,10 +287,20 @@ impl Tree {
         // we adjust the scroll
         let l = l as i32;
         let sel = self.selection as i32;
-        if dy < 0 && sel < self.scroll + 5 {
-            self.scroll = (self.scroll + 2 * dy).max(0);
-        } else if dy > 0 && l > page_height && sel > self.scroll + page_height - 5 {
-            self.scroll += 2 * dy;
+        if l > page_height {
+            if dy < 0 { // -1
+                if sel == l - 1 { // cycling
+                    self.scroll = l - page_height;
+                } else if sel < self.scroll + 5 {
+                    self.scroll = (self.scroll + 2 * dy).max(0);
+                }
+            } else { // +1
+                if sel == 0 { // cycling brought us back to top
+                    self.scroll = 0;
+                } else if sel > self.scroll + page_height - 5 {
+                    self.scroll = (self.scroll + 2 * dy).min(l - page_height);
+                }
+            }
         }
     }
     pub fn try_scroll(&mut self, dy: i32, page_height: i32) {