make row.contents_diff not require the row index

3 files changed, 14 insertions, 17 deletions

diff --git a/src/grid.rs b/src/grid.rs
index 0e0ff9d..075e604 100644
--- a/src/grid.rs
+++ b/src/grid.rs
@@ -176,12 +176,10 @@ impl Grid {
         let mut final_col = prev.pos.col;
         for (idx, (row, prev_row)) in self.rows().zip(prev.rows()).enumerate()
         {
-            let (mut new_contents, new_attrs, new_col) = row.contents_diff(
-                idx.try_into().unwrap(),
-                prev_row,
-                prev_attrs,
-            );
+            let (mut new_contents, new_attrs, new_col) =
+                row.contents_diff(prev_row, prev_attrs);
             if !new_contents.is_empty() {
+                contents.extend(format!("\x1b[{};1H", idx + 1).as_bytes());
                 final_row = idx.try_into().unwrap();
                 final_col = new_col;
             }
diff --git a/src/row.rs b/src/row.rs
index cf47374..fb31594 100644
--- a/src/row.rs
+++ b/src/row.rs
@@ -125,11 +125,10 @@ impl Row {
 
     pub fn contents_diff(
         &self,
-        row_idx: u16,
         prev: &Self,
         attrs: crate::attrs::Attrs,
     ) -> (Vec<u8>, crate::attrs::Attrs, u16) {
-        let mut needs_move = true;
+        let mut skip = 0;
         let mut contents = vec![];
         let mut prev_attrs = attrs;
         let mut final_col = 0;
@@ -137,14 +136,11 @@ impl Row {
             self.cells().zip(prev.cells()).enumerate()
         {
             if cell == prev_cell {
-                needs_move = true;
+                skip += 1;
             } else {
-                if needs_move {
-                    contents.extend(
-                        format!("\x1b[{};{}H", row_idx + 1, idx + 1)
-                            .as_bytes(),
-                    );
-                    needs_move = false;
+                if skip > 0 {
+                    contents.extend(format!("\x1b[{}C", skip).as_bytes());
+                    skip = 0;
                 }
 
                 let attrs = cell.attrs();
diff --git a/tests/window_contents.rs b/tests/window_contents.rs
index 17a54b5..1d351cb 100644
--- a/tests/window_contents.rs
+++ b/tests/window_contents.rs
@@ -329,7 +329,7 @@ fn diff() {
     let screen2 = parser.screen().clone();
     assert_eq!(
         screen2.contents_diff(&screen1),
-        b"\x1b[m\x1b[1;6H\x1b[32m bar"
+        b"\x1b[m\x1b[1;1H\x1b[5C\x1b[32m bar"
     );
     compare_diff(&screen1, &screen2, b"");
 
@@ -343,14 +343,17 @@ fn diff() {
 
     parser.process(b"\x1b[1;7H\x1b[32mbaz");
     let screen4 = parser.screen().clone();
-    assert_eq!(screen4.contents_diff(&screen3), b"\x1b[m\x1b[1;9H\x1b[32mz");
+    assert_eq!(
+        screen4.contents_diff(&screen3),
+        b"\x1b[m\x1b[1;1H\x1b[8C\x1b[32mz"
+    );
     compare_diff(&screen3, &screen4, b"\x1b[5C\x1b[32m bar\x1b[H\x1b[31mfoo");
 
     parser.process(b"\x1b[1;8H\x1b[X");
     let screen5 = parser.screen().clone();
     assert_eq!(
         screen5.contents_diff(&screen4),
-        b"\x1b[m\x1b[1;8H\x1b[X\x1b[C\x1b[1;8H"
+        b"\x1b[m\x1b[1;1H\x1b[7C\x1b[X\x1b[C\x1b[1;8H"
     );
     compare_diff(
         &screen4,