Adding two new escape sequances to render a TUI correctly.

src/perform.rs

@@ -123,6 +123,8 @@ impl<CB: crate::callbacks::Callbacks> vte::Perform for WrappedScreen<CB> {
                 'S' => self.screen.su(canonicalize_params_1(params, 1)),
                 'T' => self.screen.sd(canonicalize_params_1(params, 1)),
                 'X' => self.screen.ech(canonicalize_params_1(params, 1)),
+                '`' => self.screen.hpa(canonicalize_params_1(params, 1)),
+                'b' => self.screen.rep(canonicalize_params_1(params, 1)),
                 'd' => self.screen.vpa(canonicalize_params_1(params, 1)),
                 'm' => self.screen.sgr(params, unhandled),
                 'r' => self.screen.decstbm(canonicalize_params_decstbm(

src/screen.rs

@@ -62,6 +62,8 @@ pub struct Screen {
     modes: u8,
     mouse_protocol_mode: MouseProtocolMode,
     mouse_protocol_encoding: MouseProtocolEncoding,
+
+    last_char: Option<char>,
 }
 
 impl Screen {
@@ -81,6 +83,8 @@ impl Screen {
             modes: 0,
             mouse_protocol_mode: MouseProtocolMode::default(),
             mouse_protocol_encoding: MouseProtocolEncoding::default(),
+
+            last_char: None,
         }
     }
 
@@ -880,6 +884,7 @@ impl Screen {
                 // that self.grid().pos().col has a valid value.
                 .unwrap();
             cell.set(c, attrs);
+            self.last_char = Some(c);
             self.grid_mut().col_inc(1);
             if width > 1 {
                 let pos = self.grid().pos();
@@ -1043,6 +1048,20 @@ impl Screen {
         self.grid_mut().col_set(col - 1);
     }
 
+    // CSI `  (HPA - Horizontal Position Absolute, equivalent to CHA)
+    pub(crate) fn hpa(&mut self, col: u16) {
+        self.cha(col);
+    }
+
+    // CSI b (REP - Repeat last printed character)
+    pub(crate) fn rep(&mut self, count: u16) {
+        if let Some(c) = self.last_char {
+            for _ in 0..count {
+                self.text(c);
+            }
+        }
+    }
+
     // CSI H
     pub(crate) fn cup(&mut self, (row, col): (u16, u16)) {
         self.grid_mut().set_pos(crate::grid::Pos {

tests/csi.rs

@@ -86,3 +86,53 @@ fn xtwinops() {
         "bbbbbcccccccccccccccccccc"
     );
 }
+
+#[test]
+fn hpa() {
+    let mut vt = vt100::Parser::default();
+
+    // HPA (CSI `) is equivalent to CHA (CSI G) - Horizontal Position Absolute
+    vt.process(b"hello");
+    assert_eq!(vt.screen().cursor_position(), (0, 5));
+
+    // Move to column 10 (1-indexed, so position 9)
+    vt.process(b"\x1b[10`");
+    assert_eq!(vt.screen().cursor_position(), (0, 9));
+
+    // Move to column 1 (default)
+    vt.process(b"\x1b[`");
+    assert_eq!(vt.screen().cursor_position(), (0, 0));
+
+    // Move to column 50
+    vt.process(b"\x1b[50`");
+    assert_eq!(vt.screen().cursor_position(), (0, 49));
+
+    // Clamp to screen width (80 columns, so max position is 79)
+    vt.process(b"\x1b[500`");
+    assert_eq!(vt.screen().cursor_position(), (0, 79));
+}
+
+#[test]
+fn rep() {
+    let mut vt = vt100::Parser::default();
+
+    // REP (CSI b) repeats the last printed character
+    vt.process(b"x\x1b[5b");
+    assert_eq!(vt.screen().rows(0, 80).next().unwrap(), "xxxxxx");
+    assert_eq!(vt.screen().cursor_position(), (0, 6));
+
+    // REP with default count of 1
+    vt.process(b"\x1b[Hy\x1b[b");
+    assert_eq!(vt.screen().rows(0, 80).next().unwrap(), "yyxxxx");
+    assert_eq!(vt.screen().cursor_position(), (0, 2));
+
+    // REP on a new line
+    vt.process(b"\x1b[2;1Ha\x1b[3b");
+    assert_eq!(vt.screen().rows(0, 80).nth(1).unwrap(), "aaaa");
+
+    // REP should not do anything if no character was printed yet
+    let mut vt2 = vt100::Parser::default();
+    vt2.process(b"\x1b[5b");
+    assert_eq!(vt2.screen().rows(0, 80).next().unwrap(), "");
+    assert_eq!(vt2.screen().cursor_position(), (0, 0));
+}