Extract preview dual pass live body

docs/modernization/debt.md

@@ -165,6 +165,10 @@ agent or engineer to remove them without reconstructing context from chat.
   `make_stroke_draw_immediate_main_live_pass_request(...)`; the retained path
   still owns the concrete frame mutation, sample shader setup, and final mixer
   unbind.
+- 2026-06-13: DEBT-0036 was narrowed again. `NodeStrokePreview::draw_stroke_immediate()`
+  now routes the dual-pass live body through
+  `execute_stroke_draw_immediate_dual_pass(...)`; the retained path still owns
+  the concrete frame mutation, shader setup, and preview copy behavior.
 - 2026-06-13: DEBT-0036 was narrowed again. `Canvas::draw_merge()` now routes
   the remaining per-layer branch orchestration through
   `execute_legacy_canvas_draw_merge_layer_composite(...)`; the retained path

docs/modernization/tasks.md

@@ -1745,6 +1745,36 @@ ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_composito
 cmake --build --preset windows-msvc-default --config Debug --target PanoPainter
 ```
 
+### STR-037 - Extract Preview Dual Pass Live Body
+
+Status: Done
+Score: no score movement
+Debt: `DEBT-0036`
+Scope: `src/node_stroke_preview.cpp`, `tests/paint_renderer/compositor_tests.cpp`
+
+Goal:
+
+Move the remaining `NodeStrokePreview::draw_stroke_immediate()` dual-pass live
+body into a retained helper so the callsite keeps only sequence orchestration
+and preview copy handling.
+
+Closeout: `a2e805f9`
+
+Done Checks:
+
+- `NodeStrokePreview::draw_stroke_immediate()` no longer owns the dual-pass live
+  body inline.
+- Regression coverage proves the helper preserves the dual-pass callback order
+  and preview copy behavior.
+- `docs/modernization/debt.md` records the reduced dual-pass live surface.
+
+Validation:
+
+```powershell
+ctest --preset desktop-fast --build-config Debug -R "pp_paint_renderer_compositor|pp_paint_renderer_stroke_execution" --output-onfailure
+cmake --build --preset windows-msvc-default --config Debug --target PanoPainter
+```
+
 ### STR-010 - Extract Remaining Draw Merge Composite Orchestration
 
 ### STR-016 - Extract Draw Merge Layer Composite Execution

src/node_stroke_preview.cpp

@@ -748,34 +748,13 @@ void NodeStrokePreview::draw_stroke_immediate()
                 bind_stroke_preview_dual_pass_textures(*dual_brush);
             },
             .execute_dual_pass = [&] {
-                pp::panopainter::execute_legacy_stroke_preview_live_pass(
+                execute_stroke_draw_immediate_dual_pass(
-                    [&] {
+                    *b,
-                        m_rtt.clear();
+                    pass_orchestration,
-                    },
+                    dual_brush,
-                    [&] {
+                    copy_stroke_destination,
-                        return stroke_draw_compute(m_dual_stroke, zoom);
+                    zoom,
-                    },
+                    size);
-                    [](auto& frame) {
-                        frame.col = { 0, 0, 0, 1 };
-                    },
-                    [&](auto& frame) {
-                        pp::panopainter::use_legacy_stroke_shader();
-                        pp::panopainter::apply_legacy_stroke_sample_uniforms(
-                            pp::panopainter::LegacyStrokeSampleUniforms {
-                                .color = frame.col,
-                                .alpha = frame.flow,
-                                .opacity = frame.opacity,
-                            });
-                    },
-                    [&](auto& frame) {
-                        /*auto rect =*/ stroke_draw_samples(frame.shapes, m_tex_dual, copy_stroke_destination);
-                    },
-                    [&] {
-                        copy_stroke_preview_framebuffer_to_texture(
-                            m_tex_dual,
-                            size,
-                            stroke_preview_composite_slots::kStroke);
-                    });
             },
             .capture_background = [&] {
                 execute_stroke_preview_background_capture_pass(
@@ -893,6 +872,46 @@ NodeStrokePreview::make_stroke_draw_immediate_main_live_pass_request(
     };
 }
 
+void NodeStrokePreview::execute_stroke_draw_immediate_dual_pass(
+    const Brush& brush,
+    const pp::panopainter::LegacyNodeStrokePreviewPassOrchestrationPlan& pass_orchestration,
+    std::shared_ptr<Brush> dual_brush,
+    bool copy_stroke_destination,
+    float zoom,
+    const glm::vec2& size)
+{
+    (void)pass_orchestration;
+    (void)dual_brush;
+    pp::panopainter::execute_legacy_stroke_preview_live_pass(
+        [&] {
+            m_rtt.clear();
+        },
+        [&] {
+            return stroke_draw_compute(m_dual_stroke, zoom);
+        },
+        [](auto& frame) {
+            frame.col = { 0, 0, 0, 1 };
+        },
+        [&](auto& frame) {
+            pp::panopainter::use_legacy_stroke_shader();
+            pp::panopainter::apply_legacy_stroke_sample_uniforms(
+                pp::panopainter::LegacyStrokeSampleUniforms {
+                    .color = frame.col,
+                    .alpha = frame.flow,
+                    .opacity = frame.opacity,
+                });
+        },
+        [&](auto& frame) {
+            /*auto rect =*/ stroke_draw_samples(frame.shapes, m_tex_dual, copy_stroke_destination);
+        },
+        [&] {
+            copy_stroke_preview_framebuffer_to_texture(
+                m_tex_dual,
+                size,
+                stroke_preview_composite_slots::kStroke);
+        });
+}
+
 Image NodeStrokePreview::render_to_image()
 {
     std::lock_guard<std::mutex> _lock(s_render_mutex);

src/node_stroke_preview.h

@@ -59,6 +59,13 @@ public:
         bool copy_stroke_destination,
         float zoom,
         const glm::vec2& size);
+    void execute_stroke_draw_immediate_dual_pass(
+        const Brush& brush,
+        const pp::panopainter::LegacyNodeStrokePreviewPassOrchestrationPlan& pass_orchestration,
+        std::shared_ptr<Brush> dual_brush,
+        bool copy_stroke_destination,
+        float zoom,
+        const glm::vec2& size);
     void draw_stroke();
     void draw_stroke_immediate();
     Image render_to_image();