From dc5efa534b80264f2e5a83ab60056c0834925aea Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Wed, 20 Nov 2019 06:06:36 -0500
Subject: handle wrapped cursors properly on output

---
 src/grid.rs | 48 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 2 deletions(-)

(limited to 'src/grid.rs')

diff --git a/src/grid.rs b/src/grid.rs
index 80d44ba..8076a6c 100644
--- a/src/grid.rs
+++ b/src/grid.rs
@@ -212,7 +212,29 @@ impl Grid {
             wrapping = row.wrapped();
         }
 
-        crate::term::MoveFromTo::new(prev_pos, self.pos).write_buf(contents);
+        // writing a character to the last column of a row doesn't wrap the
+        // cursor immediately - it waits until the next character is actually
+        // drawn. it is only possible for the cursor to have this kind of
+        // position after drawing a character though, so if we end in this
+        // position, we need to redraw the character at the end of the row.
+        if prev_pos != self.pos && self.pos.col >= self.size.cols {
+            let mut pos = Pos {
+                row: self.pos.row,
+                col: self.size.cols - 2,
+            };
+            if !self.visible_cell(pos).unwrap().is_wide() {
+                pos = Pos {
+                    row: self.pos.row,
+                    col: self.size.cols - 1,
+                };
+            }
+            crate::term::MoveFromTo::new(prev_pos, pos).write_buf(contents);
+            let cell = self.visible_cell(pos).unwrap();
+            contents.extend(cell.contents().as_bytes());
+        } else {
+            crate::term::MoveFromTo::new(prev_pos, self.pos)
+                .write_buf(contents);
+        }
 
         prev_attrs
     }
@@ -244,7 +266,29 @@ impl Grid {
             wrapping = row.wrapped();
         }
 
-        crate::term::MoveFromTo::new(prev_pos, self.pos).write_buf(contents);
+        // writing a character to the last column of a row doesn't wrap the
+        // cursor immediately - it waits until the next character is actually
+        // drawn. it is only possible for the cursor to have this kind of
+        // position after drawing a character though, so if we end in this
+        // position, we need to redraw the character at the end of the row.
+        if prev_pos != self.pos && self.pos.col >= self.size.cols {
+            let mut pos = Pos {
+                row: self.pos.row,
+                col: self.size.cols - 2,
+            };
+            if !self.visible_cell(pos).unwrap().is_wide() {
+                pos = Pos {
+                    row: self.pos.row,
+                    col: self.size.cols - 1,
+                };
+            }
+            crate::term::MoveFromTo::new(prev_pos, pos).write_buf(contents);
+            let cell = self.visible_cell(pos).unwrap();
+            contents.extend(cell.contents().as_bytes());
+        } else {
+            crate::term::MoveFromTo::new(prev_pos, self.pos)
+                .write_buf(contents);
+        }
 
         prev_attrs
     }
-- 
cgit v1.2.3-54-g00ecf