From 044b09922743d587d6bec42fe3f66c1ca569e3d3 Mon Sep 17 00:00:00 2001
From: Tim Culverhouse <tim@timculverhouse.com>
Date: Mon, 10 Jun 2024 05:43:59 -0500
Subject: [PATCH] widgets(terminal): handle scrolling_region in CUU, CUD

---
 src/widgets/terminal/Screen.zig   |  5 +----
 src/widgets/terminal/Terminal.zig | 24 ++++++++++++++++++------
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/widgets/terminal/Screen.zig b/src/widgets/terminal/Screen.zig
index ef3ab87..c83f86e 100644
--- a/src/widgets/terminal/Screen.zig
+++ b/src/widgets/terminal/Screen.zig
@@ -318,10 +318,7 @@ pub fn cursorLeft(self: *Screen, n: usize) void {
             self.scrolling_region.left,
         )
     else
-        self.cursor.col = @max(
-            self.cursor.col -| n,
-            0,
-        );
+        self.cursor.col = self.cursor.col -| n;
 }
 
 pub fn eraseRight(self: *Screen) void {
diff --git a/src/widgets/terminal/Terminal.zig b/src/widgets/terminal/Terminal.zig
index dc6d479..f84154e 100644
--- a/src/widgets/terminal/Terminal.zig
+++ b/src/widgets/terminal/Terminal.zig
@@ -255,18 +255,30 @@ fn run(self: *Terminal) !void {
             .ss3 => |ss3| std.log.err("unhandled ss3: {c}", .{ss3}),
             .csi => |seq| {
                 switch (seq.final) {
-                    'A' => {
+                    'A', 'k' => {
                         var iter = seq.iterator(u16);
                         const delta = iter.next() orelse 1;
-                        self.back_screen.cursor.row = self.back_screen.cursor.row -| delta;
+                        if (self.back_screen.withinScrollingRegion())
+                            self.back_screen.cursor.row = @max(
+                                self.back_screen.cursor.row -| delta,
+                                self.back_screen.scrolling_region.top,
+                            )
+                        else
+                            self.back_screen.cursor.row = self.back_screen.cursor.row -| delta;
                     },
                     'B' => { // CUD
                         var iter = seq.iterator(u16);
                         const delta = iter.next() orelse 1;
-                        self.back_screen.cursor.row = @min(
-                            self.back_screen.height - 1,
-                            self.back_screen.cursor.row + delta,
-                        );
+                        if (self.back_screen.withinScrollingRegion())
+                            self.back_screen.cursor.row = @min(
+                                self.back_screen.scrolling_region.bottom,
+                                self.back_screen.cursor.row + delta,
+                            )
+                        else
+                            self.back_screen.cursor.row = @min(
+                                self.back_screen.height - 1,
+                                self.back_screen.cursor.row + delta,
+                            );
                     },
                     'C' => {
                         self.back_screen.cursor.pending_wrap = false;