Fix first cell when selection is off screen

Since the expansion of the selection was done after clamping it to the
grid, the selection would incorrectly move the clamped start over by one
cell when the start was to the right of the original column. By
resetting the side of the start point to `Left` before expanding, this
can be circumvented.

This also resolves a regression which broke backwards bracket selection.

Fixes #3223.

1 files changed, 6 insertions, 12 deletions

diff --git a/alacritty_terminal/src/grid/mod.rs b/alacritty_terminal/src/grid/mod.rs
index 53f7ebea..9c26fac0 100644
--- a/alacritty_terminal/src/grid/mod.rs
+++ b/alacritty_terminal/src/grid/mod.rs
@@ -158,22 +158,16 @@ impl<T: GridCell + PartialEq + Copy> Grid<T> {
         }
     }
 
-    pub fn buffer_to_visible(&self, point: impl Into<Point<usize>>) -> Point<usize> {
+    pub fn buffer_to_visible(&self, point: impl Into<Point<usize>>) -> Option<Point<usize>> {
         let mut point = point.into();
 
-        let offset = point.line.saturating_sub(self.display_offset);
-
-        if point.line < self.display_offset {
-            point.col = self.num_cols();
-            point.line = self.num_lines().0 - 1;
-        } else if offset >= *self.num_lines() {
-            point.col = Column(0);
-            point.line = 0;
-        } else {
-            point.line = self.lines.0 - offset - 1;
+        if point.line < self.display_offset || point.line >= self.display_offset + self.lines.0 {
+            return None;
         }
 
-        point
+        point.line = self.lines.0 + self.display_offset - point.line - 1;
+
+        Some(point)
     }
 
     pub fn visible_to_buffer(&self, point: Point) -> Point<usize> {