refactor: extract export selection menu item

Author: robertvokac

NEXT.md

@@ -99,7 +99,7 @@ before when explicitly requested (`SYS-W14-##` rows).
 
 ## 2. Current status
 
-- **Last full build: clean after the current Phase 13 File-merge-scene
+- **Last full build: clean after the current Phase 13 File-export-selection
   slice.** Testing is enabled in the current Ninja Release tree, and
   `CCACHE_DISABLE=1 cmake --build b-release -j4` linked all targets successfully
   on EASYGL. Alternate-backend runtime qualification remains blocked.
@@ -790,8 +790,8 @@ Edit-snap-selection-to-grid, Edit-mirror-selection, Edit-group-scale,
 Edit-linear-array, Edit-scatter-along-curve, Edit-batch-rename,
 Edit-find-replace-names, Edit-randomize-transform, Edit-macro-recording,
 Edit-play-macro, Edit-macro-editor, Edit-lock-selection, Edit-reset-transform,
-Edit-transform-clipboard, Edit-isolate-selection, Edit-hide-selection, and
-Edit-show-all-hidden and File-merge-scene slices.
+Edit-transform-clipboard, Edit-isolate-selection, Edit-hide-selection,
+Edit-show-all-hidden, File-merge-scene, and File-export-selection slices.
 `EditHistoryContext` exposes only `canUndo`/`canRedo` plus Undo, Redo, and
 Open History callbacks; `Editor::UndoManager`, document replacement,
 selection restoration, dialog state, and keyboard handling remain
@@ -958,15 +958,15 @@ dispatch.
 buffers, source-file loading, document merging, undo, title and status updates,
 and error handling remain in their existing owners; `MenuBar` owns only the
 unchanged label and click dispatch.
+`FileExportSelectionContext` exposes only current-selection availability and one
+open-dialog callback. Selection state, dialog state and buffers, export
+implementation, document and error handling remain in their existing owners;
+`MenuBar` owns only the unchanged label, availability, and click dispatch.
 
-**Next candidate, not yet authorized:** continue Phase 13 with the single
-File-menu Export Selection… item, passing only current-selection availability
-and one open-dialog callback. Selection state, dialog state and buffers, export
-implementation, document and error handling would remain in their existing
-owners; `MenuBar` would own only the unchanged label, availability, and click
-dispatch. Other File items, later controls, and the View-menu Bloom/SSAO block
-remain outside that slice. Per `CLAUDE.md`, describe and confirm the
-Export-Selection item before implementing it.
+**Next candidate, not yet authorized:** identify the next narrow File-menu
+item before implementation. The remaining File controls and the View-menu
+Bloom/SSAO block remain outside this completed slice. Per `CLAUDE.md`, describe
+and confirm any next item before implementing it.
 
 ## 9. Do not do yet
 

include/MeshCraft/Application/UI/MenuBar.hpp

@@ -34,6 +34,11 @@ struct FileMergeSceneContext {
     std::function<void()> openDialog;
 };
 
+struct FileExportSelectionContext {
+    bool canExport;
+    std::function<void()> openDialog;
+};
+
 struct EditHistoryContext {
     bool canUndo;
     bool canRedo;
@@ -220,6 +225,7 @@ class MenuBar final {
 public:
     static void drawAddMenu(const std::function<void(Mc3::ObjectType)>& addPrimitive);
     static void drawFileMergeScene(const FileMergeSceneContext& context);
+    static void drawFileExportSelection(const FileExportSelectionContext& context);
     static void drawEditClipboard(const EditClipboardContext& context);
     static void drawEditCopyProperties(const EditCopyPropertiesContext& context);
     static void drawEditGrouping(const EditGroupingContext& context);

plan.md

@@ -174,8 +174,9 @@ still internally consistent.
    Edit-find-replace-names, Edit-randomize-transform, Edit-macro-recording,
    Edit-play-macro, Edit-macro-editor, Edit-lock-selection,
    Edit-reset-transform, Edit-transform-clipboard, Edit-isolate-selection,
-   Edit-hide-selection, Edit-show-all-hidden, and File-merge-scene menu slices
-   are implemented and verified. Their state remains in the existing
+   Edit-hide-selection, Edit-show-all-hidden, File-merge-scene, and
+   File-export-selection menu slices are implemented and verified. Their state
+   remains in the existing
    editor/application owners;
    `Application::UI::MenuBar` receives only the read-only values and callbacks
    required for presentation. Any further slice requires its own confirmation
@@ -774,8 +775,9 @@ _All items in this workstream are DONE — archived to [`docs/history/plan_20260
   Edit-find-replace-names, Edit-randomize-transform, Edit-macro-recording,
   Edit-play-macro, Edit-macro-editor, Edit-lock-selection,
   Edit-reset-transform, Edit-transform-clipboard, Edit-isolate-selection,
-  Edit-hide-selection, Edit-show-all-hidden, and File-merge-scene slices, each
-  incremental Release link and the same 147/147 + 34/34 partitions pass again.
+  Edit-hide-selection, Edit-show-all-hidden, File-merge-scene, and
+  File-export-selection slices, each incremental Release link and the same
+  147/147 + 34/34 partitions pass again.
   For the current MenuBar slices, the public UI header also compiles as a
   self-contained C++23 include, `undo_snapshot_lint_test.py` passes, and
   `git diff --check` is clean. A further Phase 13 slice requires separate

src/MeshCraft/Application/UI/MenuBar.cpp

@@ -90,16 +90,15 @@ float MeshCraftApplication::drawMenuBar()
             // black box (see runObjExport()'s own comment) rather than a
             // second from-scratch scene-traversal implementation.
             if (ImGui::MenuItem("Export OBJ...")) exportObj();
-            {
-                bool hasSel = !selection_.selection().empty();
-                if (!hasSel) ImGui::BeginDisabled();
-                if (ImGui::MenuItem("Export Selection...", nullptr, false, hasSel)) {
+            const UI::FileExportSelectionContext fileExportSelectionContext{
+                .canExport = !selection_.selection().empty(),
+                .openDialog = [this] {
                     selExportBuf_[0] = '\0';
                     selExportErr_[0] = '\0';
                     selExportOpen_   = true;
-                }
-                if (!hasSel) ImGui::EndDisabled();
-            }
+                },
+            };
+            UI::MenuBar::drawFileExportSelection(fileExportSelectionContext);
             const UI::FileMergeSceneContext fileMergeSceneContext{
                 .openDialog = [this] {
                     mergeSceneBuf_[0] = '\0';
@@ -586,6 +585,14 @@ void MenuBar::drawFileMergeScene(const FileMergeSceneContext& context) {
     if (ImGui::MenuItem("Merge Scene...")) context.openDialog();
 }
 
+void MenuBar::drawFileExportSelection(const FileExportSelectionContext& context) {
+    if (!context.canExport) ImGui::BeginDisabled();
+    if (ImGui::MenuItem("Export Selection...", nullptr, false, context.canExport)) {
+        context.openDialog();
+    }
+    if (!context.canExport) ImGui::EndDisabled();
+}
+
 void MenuBar::drawEditHistory(const EditHistoryContext& context) {
     if (ImGui::MenuItem("Undo", "Ctrl+Z", false, context.canUndo)) context.undo();
     if (ImGui::MenuItem("Redo", "Ctrl+Y", false, context.canRedo)) context.redo();