fix(cellbuf): ensure inline mode first cursor movement moves to first…

… column

When using the relative cursor mode, the first cursor movement should
move the cursor to the first column before moving to the target
position. This is necessary to ensure that the cursor is in the correct
position on first render.

cellbuf/screen.go

@@ -239,6 +239,12 @@ func moveCursor(s *Screen, x, y int, overwrite bool) (seq string) {
 
 // moveCursor moves the cursor to the specified position.
 func (s *Screen) moveCursor(x, y int, overwrite bool) {
+	if s.opts.RelativeCursor && s.cur.X == -1 && s.cur.Y == -1 {
+		// First cursor movement in inline mode, move the cursor to the first
+		// column before moving to the target position.
+		s.buf.WriteByte('\r') //nolint:errcheck
+		s.cur.X, s.cur.Y = 0, 0
+	}
 	s.buf.WriteString(moveCursor(s, x, y, overwrite)) //nolint:errcheck
 	s.cur.X, s.cur.Y = x, y
 }
@@ -1334,10 +1340,6 @@ func (s *Screen) render() {
 	s.queuedText = false
 }
 
-// undefinedPos is the position used when the cursor position is undefined and
-// in its initial state.
-var undefinedPos = Pos(-1, -1)
-
 // Close writes the final screen update and resets the screen.
 func (s *Screen) Close() (err error) {
 	s.mu.Lock()
@@ -1372,11 +1374,7 @@ func (s *Screen) Close() (err error) {
 func (s *Screen) reset() {
 	s.cursorHidden = false
 	s.altScreenMode = false
-	if s.opts.RelativeCursor {
-		s.cur = Cursor{}
-	} else {
-		s.cur = Cursor{Position: undefinedPos}
-	}
+	s.cur = Cursor{Position: Pos(-1, -1)} // start at -1 to force a move
 	s.saved = s.cur
 	s.touch = make(map[int]lineData, s.newbuf.Height())
 	if s.curbuf != nil {