refactor: extract gizmo drag overlay

Author: robertvokac

NEXT.md

@@ -20,7 +20,7 @@ replacing the former flat `src/MeshCraft/MeshCraftApplication_*.cpp` layout.
 `MeshCraft::Application::MeshCraftApplication`; the old public include remains
 a compatibility forwarder. Actual UI components currently cover Validation,
 Registry results, Toolbar tools/display/snap-surface/proportional/grid controls,
-Properties delegation, Camera Preset Overlay, and the View-menu panel/overlay/direction/focus/
+Properties delegation, Camera Preset Overlay, Gizmo Drag Overlay, and the View-menu panel/overlay/direction/focus/
 Camera-Bookmarks/Walk-Mode/Bloom-SSAO presentation, plus the Add/CSG and Help menu
 presentation and the Edit-history, clipboard, object-action, and
 selection-action groups, the Select-by-Type/Tag/Material, Align-Selection,
@@ -105,7 +105,7 @@ before when explicitly requested (`SYS-W14-##` rows).
 ## 2. Current status
 
 - **Last full build: clean after the current Phase 13 File-open-recent,
-  View-Bloom/SSAO, SSAO-regression, and Camera Preset Overlay slices.** Testing is enabled in the current Ninja Release tree, and
+  View-Bloom/SSAO, SSAO-regression, Camera Preset Overlay, and Gizmo Drag Overlay slices.** 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.
 - **Tests:** the fresh Release tree registers 182 tests. All passed again after
@@ -174,7 +174,7 @@ before when explicitly requested (`SYS-W14-##` rows).
   application into `MeshCraft::Application`, organized implementation files
   by application/UI ownership, and is extracting UI presentation through
   narrow contexts. Validation, Registry results, Toolbar controls, Properties
-  delegation, Camera Preset Overlay, and the View-menu directions/focus/overlays/panels/
+  delegation, Camera Preset Overlay, Gizmo Drag Overlay, and the View-menu directions/focus/overlays/panels/
   Camera-Bookmarks/Walk-Mode/Bloom-SSAO presentation, plus the Add/CSG and Help menu
   presentation and the Edit-history, clipboard, object-action, and
   selection-action groups, the Select-by-Type/Tag/Material, Align-Selection,
@@ -224,6 +224,14 @@ before when explicitly requested (`SYS-W14-##` rows).
   camera-preset regression still verifies the shared Front/Top/Right/Persp
   table; the extracted header compiles independently and the Xvfb `smoke_test`
   passed after the move.
+- **Recently implemented (2026-07-25):** the follow-up overlay audit moved the
+  cursor-following gizmo drag-delta display into
+  `Application::UI::GizmoDragOverlay`. Its context receives only axis index,
+  current/start transform values, unit, and rotation/snap snapshots. The
+  application retains gizmo and selection lifetime, transform inspection, and
+  every mutation path. It preserves the X/Y/Z colors, signed delta, units, and
+  Ctrl-or-grid rotation snap indicator; the header compiles independently and
+  the focused `mc3_commands` plus Xvfb `smoke_test` regressions passed.
 - **Recently implemented (2026-07-20 through 2026-07-25):** all 7
   raw-OpenGL(ES)-vs-CNA migrations, `AUD-082` through `AUD-088` — full
   detail with file:line evidence and
@@ -825,7 +833,7 @@ git stash pop && cmake --build b-release -j4 --target <affected-target>
 No actionable follow-up audit task remains: `AUD-089` through `AUD-092` are
 complete, while Android (`AUD-042`) is environment/owner deferred.
 `SYS-W3-01` has 12 completed subsystem phases and an active Phase 13 for
-application/UI ownership. The authorized Camera Bookmarks, Camera Preset Overlay, Walk Mode, View
+application/UI ownership. The authorized Camera Bookmarks, Camera Preset Overlay, Gizmo Drag Overlay, Walk Mode, View
 Bloom/SSAO, Help, Add/CSG, Edit-history, Edit-clipboard, and Edit-object-actions
 menu slices are implemented and verified, together with Edit-selection-actions,
 Edit-select-by-type/tag/material, Edit-copy-properties, Edit-grouping,
@@ -1073,7 +1081,12 @@ one item does not authorize the next.
    `Application::UI::CameraPresetOverlay`; camera mutation, document-camera
    lookup, selection, and rendering remain application-owned.
 
-2. **Fresh post-overlay boundary audit.** Identify the next coherent
+2. **First post-overlay follow-up — complete.** The cursor-following gizmo
+   drag-delta display is now `Application::UI::GizmoDragOverlay`. The
+   application computes a read-only transform/snap snapshot; axis colors,
+   signed delta, units, and snap presentation are component-owned.
+
+3. **Fresh post-overlay boundary audit.** Identify the next coherent
    presentation-only cluster before changing `MeshCraftApplication`; avoid a
    broad `Overlays.cpp` extraction or a context that exposes document/renderer
    internals.

include/MeshCraft/Application/UI/GizmoDragOverlay.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <string_view>
+
+namespace MeshCraft::Application::UI {
+
+struct GizmoDragOverlayContext {
+    int axisIndex;
+    float currentValue;
+    float startValue;
+    std::string_view unit{""};
+    bool isRotation;
+    bool snapEnabled;
+    float snapRotation;
+};
+
+class GizmoDragOverlay final {
+public:
+    static void draw(const GizmoDragOverlayContext& context);
+};
+
+} // namespace MeshCraft::Application::UI

plan.md

@@ -164,7 +164,7 @@ still internally consistent.
    research pass.
 6. **SYS-W3-01 (P2/W3), Phase 13 is active:** application/UI ownership is
    being reduced one narrow presentation slice at a time. The authorized
-   Camera Bookmarks, Camera Preset Overlay, Walk Mode, View Bloom/SSAO, Help, Add/CSG, Edit-history,
+   Camera Bookmarks, Camera Preset Overlay, Gizmo Drag Overlay, Walk Mode, View Bloom/SSAO, Help, Add/CSG, Edit-history,
    Edit-clipboard,
    Edit-object-actions, Edit-selection-actions, Edit-select-by-type,
    Edit-select-by-tag/material, Edit-copy-properties, Edit-grouping,
@@ -187,7 +187,10 @@ still internally consistent.
    resulting camera-preset/projection/look-through control candidate is now
    component-owned as `Application::UI::CameraPresetOverlay`; the application
    still owns `EditorCamera`, document-camera lookup, selection, and rendering.
-   The next Phase 13 action is a fresh narrow boundary audit.
+   The following narrow audit also moved the gizmo drag-delta presentation into
+   `Application::UI::GizmoDragOverlay`; the application supplies only axis,
+   transform snapshots, and snap state. The next Phase 13 action is a fresh
+   narrow boundary audit.
 
 ---
 
@@ -619,6 +622,10 @@ _All items in this workstream are DONE — archived to [`docs/history/plan_20260
   presentation. Its context carries only projection/look-through snapshots,
   an optional selected-camera name, and callbacks; the application retains
   camera reset/orbit mutation, document access, and all render-state decisions.
+  `Application::UI::GizmoDragOverlay` likewise owns the cursor-following
+  drag-delta presentation, including axis color, signed delta, units, and the
+  rotation snap indicator. `Overlays.cpp` retains gizmo/selection inspection
+  and supplies a read-only snapshot; the component cannot mutate scene state.
   The bookmark state remains the already-extracted
   `Editor::CameraBookmarks`; a `CameraBookmarksContext` exposes only the
   read-only slots plus Save/Restore callbacks, leaving camera mutation and
@@ -794,7 +801,8 @@ _All items in this workstream are DONE — archived to [`docs/history/plan_20260
   Edit-hide-selection, Edit-show-all-hidden, File-merge-scene,
   File-export-selection, File-export-GLB, File-export-OBJ, File-save,
   File-save-as, File-import-OBJ, File-new, File-open, File-open-recent, and
-  File-exit slices, the Bloom/SSAO controls, and the CameraPresetOverlay,
+  File-exit slices, the Bloom/SSAO controls, CameraPresetOverlay, and
+  GizmoDragOverlay,
   each incremental Release link and the same 147/147 + 35/35 partitions pass
   again.
   For the current MenuBar slices, the public UI header also compiles as a
@@ -804,7 +812,9 @@ _All items in this workstream are DONE — archived to [`docs/history/plan_20260
   normal and `MESHCRAFT_TEST_FORCE_SSAO=1` renders, rather than merely proving
   that the SSAO path exits cleanly. The CameraPresetOverlay also preserves the
   tested shared preset table while reducing `Overlays.cpp` to state snapshots
-  and callbacks. The next Phase 13 action is a fresh narrow-boundary audit.
+  and callbacks. GizmoDragOverlay follows the same boundary for a pure
+  read-only drag snapshot. The next Phase 13 action is a fresh narrow-boundary
+  audit.
   **SYS-W3-01 roadmap status after this session's investigation round:**
   Phases 1–12 done (Keybindings, Preferences, MacroRecorder, UndoManager,
   animation-override computation, WalkController, AudioPreview,

src/MeshCraft/Application/UI/GizmoDragOverlay.cpp

@@ -0,0 +1,46 @@
+#include "MeshCraft/Application/UI/GizmoDragOverlay.hpp"
+
+#include <imgui.h>
+
+namespace MeshCraft::Application::UI {
+
+void GizmoDragOverlay::draw(const GizmoDragOverlayContext& context)
+{
+    ImVec2 mousePosition = ImGui::GetIO().MousePos;
+    ImGui::SetNextWindowPos(ImVec2(mousePosition.x + 18.0f, mousePosition.y - 10.0f),
+                            ImGuiCond_Always);
+    ImGui::SetNextWindowBgAlpha(0.75f);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(6, 4));
+    ImGui::Begin("##gizmoDelta", nullptr,
+        ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoInputs |
+        ImGuiWindowFlags_NoNav | ImGuiWindowFlags_NoMove |
+        ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoSavedSettings |
+        ImGuiWindowFlags_NoBringToFrontOnFocus);
+
+    static constexpr const char* kAxis[] = {"X", "Y", "Z"};
+    static const ImVec4 kAxisColor[] = {
+        {1.0f, 0.25f, 0.25f, 1.0f},
+        {0.25f, 1.0f, 0.25f, 1.0f},
+        {0.25f, 0.55f, 1.0f, 1.0f},
+    };
+    const float delta = context.currentValue - context.startValue;
+
+    ImGui::TextColored(kAxisColor[context.axisIndex], "%s", kAxis[context.axisIndex]);
+    ImGui::SameLine(0, 4);
+    if (delta >= 0.0f)
+        ImGui::TextColored(ImVec4(0.8f, 1.0f, 0.8f, 1.0f), "+%.4g%s", delta, context.unit.data());
+    else
+        ImGui::TextColored(ImVec4(1.0f, 0.8f, 0.8f, 1.0f), "%.4g%s", delta, context.unit.data());
+    ImGui::SameLine(0, 6);
+    ImGui::TextDisabled("(%.4g)", context.currentValue);
+    if (context.isRotation && (ImGui::GetIO().KeyCtrl || context.snapEnabled)) {
+        ImGui::SameLine(0, 6);
+        ImGui::TextColored(ImVec4(1.0f, 0.85f, 0.3f, 1.0f),
+                           "[snap %.4g\xc2\xb0]", context.snapRotation);
+    }
+
+    ImGui::End();
+    ImGui::PopStyleVar();
+}
+
+} // namespace MeshCraft::Application::UI

src/MeshCraft/Application/UI/Overlays.cpp

@@ -1,5 +1,6 @@
 #include "MeshCraft/Application/MeshCraftApplication.hpp"
 #include "MeshCraft/Application/UI/CameraPresetOverlay.hpp"
+#include "MeshCraft/Application/UI/GizmoDragOverlay.hpp"
 #include "MeshCraft/MeshCraftPrivate.hpp"
 #include "MeshCraft/EditorAlgorithms.hpp"
 #include "MeshCraft/Scene/SceneHierarchyPanel.hpp"
@@ -93,67 +94,36 @@ void MeshCraftApplication::drawStatsOverlay(int screenW, [[maybe_unused]] int sc
         (void)tlH2;
     }
 
-    // Gizmo drag delta overlay — shown near the mouse cursor while dragging
+    // Gizmo drag delta overlay — shown near the mouse cursor while dragging.
     if (gizmo_.isDragging() && selection_.hasSelection()) {
         const auto& sel0 = *selection_.selection().front();
-        int axIdx = gizmoDragAxisIdx_;
+        const int axisIndex = gizmoDragAxisIdx_;
         float curVal = 0.0f;
-        const char* unit = "";
-        const char* axName = "XYZ"[axIdx] == 'X' ? "X" : ("XYZ"[axIdx] == 'Y' ? "Y" : "Z");
-        static const char* kAxis[3] = {"X","Y","Z"};
+        std::string_view unit{""};
 
         switch (activeTool_) {
         case ActiveTool::Move:
-            curVal = sel0.transform.position[axIdx];
-            unit   = " u";
+            curVal = sel0.transform.position[axisIndex];
+            unit = " u";
             break;
         case ActiveTool::Rotate:
-            curVal = sel0.transform.rotation[axIdx];
-            unit   = "°";
+            curVal = sel0.transform.rotation[axisIndex];
+            unit = "°";
             break;
         case ActiveTool::Scale:
-            curVal = sel0.transform.scale[axIdx];
-            unit   = "";
+            curVal = sel0.transform.scale[axisIndex];
             break;
         default: break;
         }
-        float delta = curVal - gizmoDragStartVal_;
-
-        ImVec2 mp = ImGui::GetIO().MousePos;
-        ImGui::SetNextWindowPos(ImVec2(mp.x + 18.0f, mp.y - 10.0f), ImGuiCond_Always);
-        ImGui::SetNextWindowBgAlpha(0.75f);
-        ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(6, 4));
-        ImGui::Begin("##gizmoDelta", nullptr,
-            ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoInputs |
-            ImGuiWindowFlags_NoNav        | ImGuiWindowFlags_NoMove   |
-            ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoSavedSettings |
-            ImGuiWindowFlags_NoBringToFrontOnFocus);
-
-        // Axis label colored
-        static const ImVec4 kAxisCol[3] = {
-            {1.0f, 0.25f, 0.25f, 1.0f},
-            {0.25f, 1.0f, 0.25f, 1.0f},
-            {0.25f, 0.55f, 1.0f, 1.0f}
-        };
-        ImGui::TextColored(kAxisCol[axIdx], "%s", kAxis[axIdx]);
-        ImGui::SameLine(0, 4);
-        if (delta >= 0.0f)
-            ImGui::TextColored(ImVec4(0.8f, 1.0f, 0.8f, 1.0f), "+%.4g%s", delta, unit);
-        else
-            ImGui::TextColored(ImVec4(1.0f, 0.8f, 0.8f, 1.0f), "%.4g%s", delta, unit);
-        ImGui::SameLine(0, 6);
-        ImGui::TextDisabled("(%.4g)", curVal);
-        // Show snap indicator for rotate when Ctrl or snap grid is active
-        if (activeTool_ == ActiveTool::Rotate) {
-            bool ctrlDown = ImGui::GetIO().KeyCtrl;
-            if (ctrlDown || snapEnabled_) {
-                ImGui::SameLine(0, 6);
-                ImGui::TextColored(ImVec4(1.0f, 0.85f, 0.3f, 1.0f), "[snap %.4g\xc2\xb0]", snapRotate_);
-            }
-        }
-        ImGui::End();
-        ImGui::PopStyleVar();
-        (void)axName;
+        UI::GizmoDragOverlay::draw({
+            .axisIndex = axisIndex,
+            .currentValue = curVal,
+            .startValue = gizmoDragStartVal_,
+            .unit = unit,
+            .isRotation = activeTool_ == ActiveTool::Rotate,
+            .snapEnabled = snapEnabled_,
+            .snapRotation = snapRotate_,
+        });
     }
 
     // Measurement tool overlay