[fix] preserve CLI display aspect ratio across terminals

libs/terminal/include/terminal_renderer.h

@@ -21,6 +21,22 @@ struct Viewport {
   bool native = false, pixel_mode = false;
   int row_offset = 0; // Terminal rows reserved above the video area.
 };
+// Keep reported cell geometry across queries; never combine partial replies
+// from different query cycles. Pixel/cell window sizes use the full text area.
+class TerminalMetrics {
+public:
+  void BeginQuery();
+  void Report(const std::string &sequence);
+  void Apply(Viewport &) const;
+  bool Known() const { return cell_width_ > 0; }
+
+private:
+  bool SetCellSize(double width, double height);
+  double cell_width_ = 0, cell_height_ = 0;
+  int pixel_width_ = 0, pixel_height_ = 0, columns_ = 0, rows_ = 0;
+  bool queried_ = false, direct_reply_ = false;
+};
+inline constexpr char kTerminalSizeQuery[] = "\033[16t\033[14t\033[18t";
 struct Rect {
   int x, y, width, height;
 };
@@ -72,6 +88,7 @@ public:
   uint64_t mouse_reports = 0;
   uint64_t mouse_legacy_reports = 0, mouse_forwarded = 0;
   uint64_t mouse_send_failures = 0;
+  TerminalMetrics terminal_metrics;
 
 private:
   std::string pending_;

libs/terminal/src/input.cpp

@@ -238,6 +238,10 @@ void Input::Feed(const std::string &bytes, ControllerSession &s,
           return;
         std::string seq = pending_.substr(0, end + 1);
         pending_.erase(0, end + 1);
+        if (seq.back() == 't') {
+          terminal_metrics.Report(seq);
+          continue;
+        }
         if (seq == "\033[O") {
           control = false;
           s.SetControl(false);

libs/terminal/src/terminal_metrics.cpp

@@ -0,0 +1,67 @@
+#include "terminal_renderer.h"
+#include <charconv>
+#include <cmath>
+
+namespace crossdesk::terminal {
+void TerminalMetrics::BeginQuery() {
+  queried_ = true;
+  direct_reply_ = false;
+  pixel_width_ = pixel_height_ = columns_ = rows_ = 0;
+}
+
+bool TerminalMetrics::SetCellSize(double width, double height) {
+  if (width < 1 || height < 1 || width > 1024 || height > 1024 ||
+      width / height < .2 || width / height > 2)
+    return false;
+  cell_width_ = width;
+  cell_height_ = height;
+  return true;
+}
+
+void TerminalMetrics::Report(const std::string &sequence) {
+  if (!queried_ || sequence.size() < 9 || sequence.compare(0, 2, "\033[") ||
+      sequence.back() != 't')
+    return;
+  int type = 0, height = 0, width = 0;
+  const char *cur = sequence.data() + 2;
+  const char *end = sequence.data() + sequence.size() - 1;
+  for (int *value : {&type, &height, &width}) {
+    auto result = std::from_chars(cur, end, *value);
+    if (result.ec != std::errc{} || *value <= 0 || *value > 1048576)
+      return;
+    cur = result.ptr;
+    if (value != &width) {
+      if (cur == end || *cur++ != ';')
+        return;
+    } else if (cur != end) {
+      return;
+    }
+  }
+  if (type == 6) {
+    // CSI 16 t replies with character height, then width (not width/height).
+    if (SetCellSize(width, height))
+      direct_reply_ = true;
+  } else if (type == 4) {
+    pixel_width_ = width;
+    pixel_height_ = height;
+  } else if (type == 8) {
+    columns_ = width;
+    rows_ = height;
+  } else {
+    return;
+  }
+  // VTE supports text-area pixels/cells even when CSI 16 t is unavailable.
+  // Use reported full rows/columns, not the capped video viewport or status
+  // rows, and retain fractional cell dimensions for scaled terminal fonts.
+  if (!direct_reply_ && pixel_width_ && pixel_height_ && columns_ && rows_)
+    SetCellSize(double(pixel_width_) / columns_, double(pixel_height_) / rows_);
+}
+
+void TerminalMetrics::Apply(Viewport &viewport) const {
+  if (!Known())
+    return;
+  viewport.cell_aspect = cell_width_ / cell_height_;
+  viewport.pixel_width = int(std::lround(cell_width_ * viewport.columns));
+  viewport.pixel_height = int(std::lround(cell_height_ * viewport.rows));
+}
+} // namespace crossdesk::terminal