fix: preserve kitty graphics during host repaints

refs #1628

1 files changed, 22 insertions, 12 deletions

diff --git a/src/client/mod.rs b/src/client/mod.rs
index b1c363f2..23e331e8 100644
--- a/src/client/mod.rs
+++ b/src/client/mod.rs
@@ -87,6 +87,8 @@ struct ClientState {
     remote_image_paste_key: Option<(crossterm::event::KeyCode, crossterm::event::KeyModifiers)>,
     /// Whether outer focus gain should force a full host-terminal redraw.
     redraw_on_focus_gained: bool,
+    /// Whether the next semantic frame must repaint every cell without clearing the surface.
+    repaint_pending: bool,
     /// Whether this client draws the cursor into frame cells instead of using the host cursor.
     draw_host_cursor: bool,
 }
@@ -220,8 +222,8 @@ fn attach_scroll_action(
 }
 
 impl ClientState {
-    fn request_full_redraw(&mut self) {
-        self.blit_encoder = render_ansi::BlitEncoder::new();
+    fn request_repaint(&mut self) {
+        self.repaint_pending = true;
     }
 }
 
@@ -1302,6 +1304,7 @@ async fn run_client_loop(
         #[cfg(unix)]
         remote_image_paste_key: config.remote_image_paste_key,
         redraw_on_focus_gained: config.redraw_on_focus_gained,
+        repaint_pending: false,
         draw_host_cursor,
     };
     debug!(?negotiated_encoding, "client render encoding active");
@@ -1417,7 +1420,7 @@ async fn run_client_loop(
                         &events,
                         state.redraw_on_focus_gained,
                     ) {
-                        state.request_full_redraw();
+                        state.request_repaint();
                     }
                     if crate::raw_input::events_require_host_terminal_theme_query(&events) {
                         query_host_terminal_theme();
@@ -1489,7 +1492,7 @@ async fn run_client_loop(
                     &raw_events,
                     state.redraw_on_focus_gained,
                 ) {
-                    state.request_full_redraw();
+                    state.request_repaint();
                 }
                 let msg = ClientMessage::InputEvents { events };
                 if let Err(e) = write_to_server(&mut write_stream, &msg) {
@@ -1516,11 +1519,14 @@ async fn run_client_loop(
                         frame_data
                     };
                     let encoded = if state.draw_host_cursor {
+                        state.blit_encoder.encode_with_suppressed_visible_cursor(
+                            &frame_data,
+                            state.repaint_pending,
+                        )
+                    } else {
                         state
                             .blit_encoder
-                            .encode_with_suppressed_visible_cursor(&frame_data, false)
-                    } else {
-                        state.blit_encoder.encode(&frame_data, false)
+                            .encode(&frame_data, state.repaint_pending)
                     };
                     let mut stdout = io::stdout();
                     let graphics = if state.kitty_graphics_enabled {
@@ -1532,6 +1538,7 @@ async fn run_client_loop(
                         write_encoded_frame_with_graphics(&mut stdout, &encoded.bytes, graphics);
                     let _ = stdout.flush();
                     state.blit_encoder.commit(frame_data, encoded);
+                    state.repaint_pending = false;
                 }
                 ServerMessage::Terminal(frame) => {
                     if state.kitty_graphics_enabled && contains_kitty_graphics_bytes(&frame.bytes) {
@@ -1983,15 +1990,18 @@ fn write_encoded_frame_with_graphics(
     encoded: &[u8],
     graphics: &[u8],
 ) -> io::Result<()> {
-    writer.write_all(encoded)?;
     if graphics.is_empty() {
-        return Ok(());
+        return writer.write_all(encoded);
     }
 
+    let insertion = render_ansi::final_sync_output_end(encoded).unwrap_or(encoded.len());
+
+    writer.write_all(&encoded[..insertion])?;
     record_received_kitty_graphics(graphics);
     writer.write_all(b"\x1b7")?;
     writer.write_all(graphics)?;
-    writer.write_all(b"\x1b8")
+    writer.write_all(b"\x1b8")?;
+    writer.write_all(&encoded[insertion..])
 }
 
 fn contains_kitty_graphics_bytes(bytes: &[u8]) -> bool {
@@ -2360,7 +2370,7 @@ mod tests {
     }
 
     #[test]
-    fn graphics_bytes_are_written_after_blit_with_saved_cursor() {
+    fn graphics_bytes_are_written_inside_synchronized_blit_with_saved_cursor() {
         let mut output = Vec::new();
         write_encoded_frame_with_graphics(
             &mut output,
@@ -2371,7 +2381,7 @@ mod tests {
 
         assert_eq!(
             output,
-            b"\x1b[?2026htext\x1b[?2026lcursor\x1b7graphics\x1b8"
+            b"\x1b[?2026htext\x1b7graphics\x1b8\x1b[?2026lcursor"
         );
     }