Make studio python more like studio C++

- C++ Platform UX: Added a "Copy Camera" button to copy XML camera definitions to clipboard.
  - C++ Platform UX: Extracted `SetSpeedIndex` and `GetExpectedLabelWidth` into reusable platform helpers.
  - C++ Platform UX: Fixed combo box widths and removed auto-hide tab bar flag from dockspace.
  - C++ Studio App: Deduplicated label width and speed index logic by adopting platform helpers.
  - C++ Studio App: Updated the toolbar layout to use a 2-column table.
  - Python Bindings: Added pybind definitions for `set_camera_index`, `set_speed_index`, and `camera_to_string`.
  - Python Studio App: Aligned toolbar UI with C++ using a 2-column table and fixed immediate theme switching.
  - Python Studio App: Added a Help menu displaying the MuJoCo version and Stats toggle.
  - Python Events: Added `-`/`=` shortcuts for simulation speed and `Esc`/`[`/`]` shortcuts for camera selection.

PiperOrigin-RevId: 922097319
Change-Id: Iec74afe37bf5c7a1ebf1cab4141e47fff5fe9274

src/experimental/platform/ux/gui.cc

@@ -316,8 +316,7 @@ ImVec4 ConfigureDockingLayout() {
     ImGui::Begin("Dockspace", nullptr, kWorkspaceFlags);
     const ImGuiDockNodeFlags kDockSpaceFlags =
         ImGuiDockNodeFlags_PassthruCentralNode |
-        ImGuiDockNodeFlags_NoDockingOverCentralNode |
+        ImGuiDockNodeFlags_NoDockingOverCentralNode;
-        ImGuiDockNodeFlags_AutoHideTabBar;
     ImGui::DockSpace(root, ImVec2(0.0f, 0.0f), kDockSpaceFlags);
     ImGui::End();
   }
@@ -426,9 +425,7 @@ void StepControlGui(const mjModel* model, StepControl* step_control,
                         ImGuiComboFlags_NoArrowButton)) {
     for (int n = 0; n < kPercentRealTime.size(); n++) {
       if (ImGui::Selectable(kPercentRealTime[n], (speed_index == n))) {
-        speed_index = std::clamp<int>(n, 0, kPercentRealTime.size() - 1);
+        SetSpeedIndex(step_control, speed_index, n);
-        float speed = std::stof(kPercentRealTime[speed_index]);
-        step_control->SetSpeed(speed);
       }
     }
     ImGui::EndCombo();
@@ -442,6 +439,17 @@ void StepControlGui(const mjModel* model, StepControl* step_control,
   }
 }
 
+void SetSpeedIndex(StepControl* step_control, int& speed_index,
+                   int request_idx) {
+  if (!step_control || request_idx == speed_index || kPercentRealTime.empty()) {
+    return;
+  }
+
+  speed_index = std::clamp<int>(request_idx, 0, kPercentRealTime.size() - 1);
+  float speed = std::stof(kPercentRealTime[speed_index]);
+  step_control->SetSpeed(speed);
+}
+
 bool ThemeSelectGui(GuiTheme* theme, const ImVec2& size) {
   static constexpr const char* ICON_DARKMODE = ICON_FA_CIRCLE;
   static constexpr const char* ICON_LIGHTMODE = ICON_FA_CIRCLE_O;
@@ -471,6 +479,7 @@ bool LabelSelectionGui(mjvOption* opts) {
   const std::string label_preview =
       opts->label == 0 ? std::string(ICON_LABEL) + " Label"
                        : std::string(ICON_LABEL) + " " + kLabelNames[opts->label];
+  ImGui::SetNextItemWidth(GetExpectedLabelWidth());
   if (ImGui::BeginCombo("##Label", label_preview.c_str(),
                         ImGuiComboFlags_NoArrowButton)) {
     for (int n = 0; n < IM_ARRAYSIZE(kLabelNames); n++) {
@@ -494,6 +503,7 @@ bool FrameSelectionGui(mjvOption* opts) {
   const std::string frame_preview =
       opts->frame == 0 ? std::string(ICON_FRAME) + " Frame"
                        : std::string(ICON_FRAME) + " " + kFrameNames[opts->frame];
+  ImGui::SetNextItemWidth(GetExpectedLabelWidth());
   if (ImGui::BeginCombo("##Frame", frame_preview.c_str(),
                         ImGuiComboFlags_NoArrowButton)) {
     for (int n = 0; n < IM_ARRAYSIZE(kFrameNames); n++) {
@@ -530,6 +540,19 @@ static std::string GetCameraName(const mjModel* model, const mjvCamera& camera,
 bool CameraSelectionGui(const mjModel* model, mjData* data, mjvCamera& camera,
                         int& index) {
   static constexpr const char* ICON_CAMERA = ICON_FA_CAMERA;
+  static constexpr const char* ICON_COPY_CAMERA = ICON_FA_COPY;
+
+  // Copy camera button.
+  const float btn_size = ImGui::GetFrameHeight();
+  const ImVec2 square_size(btn_size, btn_size);
+  if (ImGui::Button(ICON_COPY_CAMERA, square_size)) {
+    std::string camera_string = CameraToString(data, &camera);
+    MaybeSaveToClipboard(camera_string);
+  }
+  ImGui::SetItemTooltip("%s", "Copy Camera");
+  ImGui::SameLine(0, 0);
+
+  ImGui::SetNextItemWidth(GetExpectedLabelWidth());
 
   auto select = [&](int type, int idx) {
     if (ImGui::Selectable(GetCameraName(model, camera, type).c_str(),

src/experimental/platform/ux/gui.h

@@ -84,6 +84,10 @@ static constexpr std::array<const char*, 31> kPercentRealTime = {
 void StepControlGui(const mjModel* model, StepControl* step_control,
                     int& speed_index);
 
+// Sets the simulation speed index and updates the StepControl object.
+void SetSpeedIndex(StepControl* step_control, int& speed_index,
+                   int request_idx);
+
 // UX for selecting the GUI theme.
 bool ThemeSelectGui(GuiTheme* theme, const ImVec2& size = ImVec2(0, 0));
 

src/experimental/platform/ux/imgui_widgets.cc

@@ -386,6 +386,23 @@ void MaybeSaveToClipboard(const std::string& contents) {
   ImGui::SetClipboardText(contents.c_str());
 }
 
+float GetExpectedLabelWidth() {
+  static float expected_label_width = 0;
+  if (expected_label_width == 0) {
+    int longest = 0;
+    const char* longest_label = "";
+    for (int i = 0; i < mjNVISFLAG; ++i) {
+      int length = static_cast<int>(std::strlen(mjVISSTRING[i][0]));
+      if (length > longest) {
+        longest_label = mjVISSTRING[i][0];
+        longest = length;
+      }
+    }
+    expected_label_width = ImGui::CalcTextSize(longest_label).x + 16;
+  }
+  return expected_label_width;
+}
+
 ImPlotFlags ImPlot_SetupPlotFlags(ImVec2 plot_size) {
   ImPlotFlags flags = ImPlotFlags_None;
   if (plot_size.x > 0 && plot_size.y > 0) {

src/experimental/platform/ux/imgui_widgets.h

@@ -617,6 +617,9 @@ inline void EndBoxSection() { ImGui::EndTable(); }
 // Saves the given contents to the clipboard if the clipboard is available.
 void MaybeSaveToClipboard(const std::string& contents);
 
+// Returns the expected width of a UI label based on MuJoCo visualization flags.
+float GetExpectedLabelWidth();
+
 // Returns plot flags with title/legend conditionally hidden when the plot
 // area is too small.  `plot_size` is the final rendered size of the plot.
 ImPlotFlags ImPlot_SetupPlotFlags(ImVec2 plot_size);

src/experimental/studio/app.cc

@@ -826,14 +826,7 @@ void App::SaveSettings() {
 }
 
 void App::SetSpeedIndex(int idx) {
-  if (idx == tmp_.speed_index || platform::kPercentRealTime.empty()) {
+  platform::SetSpeedIndex(&step_control_, tmp_.speed_index, idx);
-    return;
-  }
-
-  tmp_.speed_index =
-      std::clamp<int>(idx, 0, platform::kPercentRealTime.size() - 1);
-  float speed = std::stof(platform::kPercentRealTime[tmp_.speed_index]);
-  step_control_.SetSpeed(speed);
 }
 
 void App::MoveCamera(platform::CameraMotion motion, mjtNum reldx,
@@ -1022,7 +1015,7 @@ void App::BuildGui() {
 }
 
 void App::ModelOptionsGui() {
-  const float min_width = GetExpectedLabelWidth();
+  const float min_width = platform::GetExpectedLabelWidth();
   const ImGuiChildFlags child_flags =
       ImGuiChildFlags_AutoResizeY | ImGuiChildFlags_AlwaysAutoResize;
   const ImGuiTreeNodeFlags node_flags =
@@ -1064,7 +1057,7 @@ void App::DataInspectorGui() {
     return;
   }
 
-  const float min_width = GetExpectedLabelWidth();
+  const float min_width = platform::GetExpectedLabelWidth();
   const ImGuiChildFlags child_flags =
       ImGuiChildFlags_AutoResizeY | ImGuiChildFlags_AlwaysAutoResize;
   const ImGuiTreeNodeFlags node_flags =
@@ -1424,15 +1417,14 @@ void App::ToolBarGui() {
               ImVec2(ImGui::GetStyle().ItemSpacing.x * 2.0f,
                      ImGui::GetStyle().ItemSpacing.y));
 
-    const float label_width = GetExpectedLabelWidth();
+    const float label_width = platform::GetExpectedLabelWidth();
-    const float copy_btn_width = ImGui::CalcTextSize(ICON_COPY_CAMERA).x +
+    const float copy_btn_width = ImGui::GetFrameHeight();
-                                 ImGui::GetStyle().FramePadding.x * 2;
     const float theme_width =
         ImGui::CalcTextSize(platform::ICON_FA_CIRCLE_O).x +
         ImGui::GetStyle().FramePadding.x * 2;
     const float sp = ImGui::GetStyle().ItemSpacing.x;
-    const float right_width = label_width + sp + label_width + sp +
+    const float right_width = copy_btn_width + label_width + sp +
-                              label_width + sp + copy_btn_width + sp +
+                              label_width + sp + label_width + sp +
                               theme_width;
     const float separator_width = ImGui::GetFrameHeight() * .6f;
 
@@ -1467,26 +1459,15 @@ void App::ToolBarGui() {
 
     ImGui::TableNextColumn();
 
-    if (ImGui::Button(ICON_COPY_CAMERA, square_size)) {
-      std::string camera_string = platform::CameraToString(data(), &camera_);
-      platform::MaybeSaveToClipboard(camera_string);
-    }
-    ImGui::SetItemTooltip("%s", "Copy Camera");
-
-    ImGui::SameLine(0, 0);
-    ImGui::SetNextItemWidth(GetExpectedLabelWidth());
     platform::CameraSelectionGui(model(), data(), camera_, ui_.camera_idx);
 
     ImGui::SameLine();
-    ImGui::SetNextItemWidth(GetExpectedLabelWidth());
     platform::LabelSelectionGui(&vis_options_);
 
     ImGui::SameLine();
-    ImGui::SetNextItemWidth(GetExpectedLabelWidth());
     platform::FrameSelectionGui(&vis_options_);
 
     ImGui::SameLine();
-    ImGui::SetNextItemWidth(GetExpectedLabelWidth());
     if (platform::ThemeSelectGui(&ui_.theme, square_size)) {
       platform::SetupTheme(ui_.theme);
       ImGui::GetIO().WantSaveIniSettings = true;
@@ -1836,27 +1817,6 @@ void App::FileDialogGui() {
   }
 }
 
-float App::GetExpectedLabelWidth() {
-  // Find the longest label which we'll use to set the minimum toggle button
-  // width. This isn't perfect because we may have labels that are longer, but
-  // it's a good enough approximation.
-  if (tmp_.expected_label_width == 0) {
-    int longest = 0;
-    const char* longest_label = "";
-    for (int i = 0; i < mjNVISFLAG; ++i) {
-      int length = static_cast<int>(strlen(mjVISSTRING[i][0]));
-      if (length > longest) {
-        longest_label = mjVISSTRING[i][0];
-        longest = length;
-      }
-    }
-    // Pad the width a bit to account for how the labels will be displayed
-    // (e.g. as button labels or besides checkboxes).
-    tmp_.expected_label_width = ImGui::CalcTextSize(longest_label).x + 16;
-  }
-  return tmp_.expected_label_width;
-}
-
 App::UiState::Dict App::UiState::ToDict() const {
   return {
       {"theme", std::to_string(static_cast<int>(theme))},

src/experimental/studio/app.h

@@ -224,8 +224,6 @@ class App {
   void SpecExplorerGui();
   void SpecEditorGui();
 
-  float GetExpectedLabelWidth();
-
   mjSpec* spec() { return model_holder_->spec(); }
   mjModel* model() { return model_holder_->model(); }
   mjData* data() { return model_holder_->data(); }