fix(compatibility): various ansi fixes (#1324)

* fix(compatibility): rotate scroll region up properly

* fix(compatibility): rotate scroll region down properly

* style(fmt): rustfmt

4 files changed, 161 insertions, 6 deletions

diff --git a/zellij-server/src/panes/grid.rs b/zellij-server/src/panes/grid.rs
index 320308e2..b74966f3 100644
--- a/zellij-server/src/panes/grid.rs
+++ b/zellij-server/src/panes/grid.rs
@@ -822,12 +822,17 @@ impl Grid {
             .scroll_region
             .or(Some((0, self.height.saturating_sub(1))))
         {
+            self.pad_lines_until(scroll_region_bottom, EMPTY_TERMINAL_CHARACTER);
             for _ in 0..count {
                 if self.cursor.y >= scroll_region_top && self.cursor.y <= scroll_region_bottom {
-                    self.pad_lines_until(scroll_region_bottom, EMPTY_TERMINAL_CHARACTER);
                     if self.viewport.get(scroll_region_bottom).is_some() {
                         self.viewport.remove(scroll_region_bottom);
                     }
+                    let mut pad_character = EMPTY_TERMINAL_CHARACTER;
+                    pad_character.styles = self.cursor.pending_styles;
+                    let columns = VecDeque::from(vec![pad_character; self.width]);
+                    self.viewport
+                        .insert(scroll_region_top, Row::from_columns(columns).canonical());
                 }
             }
             self.output_buffer.update_all_lines(); // TODO: only update scroll region lines
@@ -838,12 +843,14 @@ impl Grid {
             .scroll_region
             .or(Some((0, self.height.saturating_sub(1))))
         {
+            self.pad_lines_until(scroll_region_bottom, EMPTY_TERMINAL_CHARACTER);
+            let mut pad_character = EMPTY_TERMINAL_CHARACTER;
+            pad_character.styles = self.cursor.pending_styles;
             for _ in 0..count {
-                if self.cursor.y >= scroll_region_top && self.cursor.y <= scroll_region_bottom {
-                    self.pad_lines_until(scroll_region_top, EMPTY_TERMINAL_CHARACTER);
-                    self.viewport.remove(scroll_region_top);
-                    self.pad_lines_until(scroll_region_bottom, EMPTY_TERMINAL_CHARACTER);
-                }
+                self.viewport.remove(scroll_region_top);
+                let columns = VecDeque::from(vec![pad_character; self.width]);
+                self.viewport
+                    .insert(scroll_region_bottom, Row::from_columns(columns).canonical());
             }
             self.output_buffer.update_all_lines(); // TODO: only update scroll region lines
         }
diff --git a/zellij-server/src/panes/unit/grid_tests.rs b/zellij-server/src/panes/unit/grid_tests.rs
index 2790c585..b0e00f9a 100644
--- a/zellij-server/src/panes/unit/grid_tests.rs
+++ b/zellij-server/src/panes/unit/grid_tests.rs
@@ -1708,6 +1708,40 @@ pub fn scroll_down_ansi() {
 }
 
 #[test]
+pub fn ansi_capital_t() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(
+        51,
+        112,
+        Palette::default(),
+        Rc::new(RefCell::new(LinkHandler::new())),
+        Rc::new(RefCell::new(None)),
+    );
+    let content = "foo\u{1b}[14Tbar".as_bytes();
+    for byte in content {
+        vte_parser.advance(&mut grid, *byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+pub fn ansi_capital_s() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(
+        51,
+        112,
+        Palette::default(),
+        Rc::new(RefCell::new(LinkHandler::new())),
+        Rc::new(RefCell::new(None)),
+    );
+    let content = "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nfoo\u{1b}[14Sbar".as_bytes();
+    for byte in content {
+        vte_parser.advance(&mut grid, *byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
 fn terminal_pixel_size_reports() {
     let mut vte_parser = vte::Parser::new();
     let mut grid = Grid::new(
diff --git a/zellij-server/src/panes/unit/snapshots/zellij_server__panes__grid__grid_tests__ansi_capital_s.snap b/zellij-server/src/panes/unit/snapshots/zellij_server__panes__grid__grid_tests__ansi_capital_s.snap
new file mode 100644
index 00000000..418f64bf
--- /dev/null
+++ b/zellij-server/src/panes/unit/snapshots/zellij_server__panes__grid__grid_tests__ansi_capital_s.snap
@@ -0,0 +1,57 @@
+---
+source: zellij-server/src/panes/./unit/grid_tests.rs
+assertion_line: 1741
+expression: "format!(\"{:?}\", grid)"
+---
+00 (C): 
+01 (C): 
+02 (C): 
+03 (C): 
+04 (C): 
+05 (C): 
+06 (C): foo
+07 (C):                                                                                                                 
+08 (C):                                                                                                                 
+09 (C):                                                                                                                 
+10 (C):                                                                                                                 
+11 (C):                                                                                                                 
+12 (C):                                                                                                                 
+13 (C):                                                                                                                 
+14 (C):                                                                                                                 
+15 (C):                                                                                                                 
+16 (C):                                                                                                                 
+17 (C):                                                                                                                 
+18 (C):                                                                                                                 
+19 (C):                                                                                                                 
+20 (C):    bar                                                                                                          
+21 (C):                                                                                                                 
+22 (C):                                                                                                                 
+23 (C):                                                                                                                 
+24 (C):                                                                                                                 
+25 (C):                                                                                                                 
+26 (C):                                                                                                                 
+27 (C):                                                                                                                 
+28 (C):                                                                                                                 
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+30 (C):                                                                                                                 
+31 (C):                                                                                                                 
+32 (C):                                                                                                                 
+33 (C):                                                                                                                 
+34 (C):                                                                                                                 
+35 (C):                                                                                                                 
+36 (C):                                                                                                                 
+37 (C):                                                                                                                 
+38 (C):                                                                                                                 
+39 (C):                                                                                                                 
+40 (C):                                                                                                                 
+41 (C):                                                                                                                 
+42 (C):                                                                                                                 
+43 (C):                                                                                                                 
+44 (C):                                                                                                                 
+45 (C):                                                                                                                 
+46 (C):                                                                                                                 
+47 (C):                                                                                                                 
+48 (C):                                                                                                                 
+49 (C):                                                                                                                 
+50 (C):                                                                                                                 
+
diff --git a/zellij-server/src/panes/unit/snapshots/zellij_server__panes__grid__grid_tests__ansi_capital_t.snap b/zellij-server/src/panes/unit/snapshots/zellij_server__panes__grid__grid_tests__ansi_capital_t.snap
new file mode 100644
index 00000000..125d3634
--- /dev/null
+++ b/zellij-server/src/panes/unit/snapshots/zellij_server__panes__grid__grid_tests__ansi_capital_t.snap
@@ -0,0 +1,57 @@
+---
+source: zellij-server/src/panes/./unit/grid_tests.rs
+assertion_line: 1724
+expression: "format!(\"{:?}\", grid)"
+---
+00 (C):    bar                                                                                                          
+01 (C):                                                                                                                 
+02 (C):                                                                                                                 
+03 (C):                                                                                                                 
+04 (C):                                                                                                                 
+05 (C):                                                                                                                 
+06 (C):                                                                                                                 
+07 (C):                                                                                                                 
+08 (C):                                                                                                                 
+09 (C):                                                                                                                 
+10 (C):                                                                                                                 
+11 (C):                                                                                                                 
+12 (C):                                                                                                                 
+13 (C):                                                                                                                 
+14 (C): foo
+15 (C):                                                                                                                 
+16 (C):                                                                                                                 
+17 (C):                                                                                                                 
+18 (C):                                                                                                                 
+19 (C):                                                                                                                 
+20 (C):                                                                                                                 
+21 (C):                                                                                                                 
+22 (C):                                                                                                                 
+23 (C):                                                                                                                 
+24 (C):                                                                                                                 
+25 (C):                                                                                                                 
+26 (C):                                                                                                                 
+27 (C):                                                                                                                 
+28 (C):                                                                                                                 
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+31 (C):                                                                                                                 
+32 (C):                                                                                                                 
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+35 (C):                                                                                                                 
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+46 (C):                                                                                                                 
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+48 (C):                                                                                                                 
+49 (C):                                                                                                                 
+50 (C):                                                                                                                 
+