Reuse stroke sampler dispatch helper

docs/modernization/tasks.md

@@ -509,6 +509,11 @@ Done Checks:
 
 Progress Notes:
 
+- 2026-06-13: `Canvas::stroke_draw()` live-pass sampler dispatch now reuses a
+  retained helper builder for brush-tip, destination, pattern, and mixer
+  sampler callbacks; the live adapter still owns the concrete sampler objects.
+  Next slice should target another narrow `stroke_draw()` seam without
+  reopening landed texture or dual-pass helpers.
 - 2026-06-13: `Canvas::stroke_draw()` main-pass texture dispatch now reuses
   retained helper builders for texture-unit, brush-tip, pattern, and mixer
   callback wiring; the live adapter still owns the concrete textures and

src/canvas.cpp

@@ -731,32 +731,32 @@ void Canvas::stroke_draw()
             .slot = 0,
         },
     };
-    const pp::panopainter::LegacyCanvasStrokeSamplerDispatch live_pass_sampler_dispatch {
+    const pp::panopainter::LegacyCanvasStrokeSamplerDispatch live_pass_sampler_dispatch =
-        .bind_brush_tip_sampler = [&](int slot) {
+        pp::panopainter::make_legacy_canvas_stroke_sampler_dispatch(
-            m_sampler_brush.bind(slot);
+            [&](int slot) {
-        },
+                m_sampler_brush.bind(slot);
-        .unbind_brush_tip_sampler = [&] {
+            },
-            m_sampler_brush.unbind();
+            [&] {
-        },
+                m_sampler_brush.unbind();
-        .bind_stroke_destination_sampler = [&](int slot) {
+            },
-            m_sampler_nearest.bind(slot);
+            [&](int slot) {
-        },
+                m_sampler_nearest.bind(slot);
-        .unbind_stroke_destination_sampler = [&] {
+            },
-            m_sampler_nearest.unbind();
+            [&] {
-        },
+                m_sampler_nearest.unbind();
-        .bind_pattern_sampler = [&](int slot) {
+            },
-            m_sampler_stencil.bind(slot);
+            [&](int slot) {
-        },
+                m_sampler_stencil.bind(slot);
-        .unbind_pattern_sampler = [&] {
+            },
-            m_sampler_stencil.unbind();
+            [&] {
-        },
+                m_sampler_stencil.unbind();
-        .bind_mixer_sampler = [&](int slot) {
+            },
-            m_sampler.bind(slot);
+            [&](int slot) {
-        },
+                m_sampler.bind(slot);
-        .unbind_mixer_sampler = [&] {
+            },
-            m_sampler.unbind();
+            [&] {
-        },
+                m_sampler.unbind();
-    };
+            });
     const pp::panopainter::LegacyCanvasStrokeTextureInputDispatch main_pass_texture_dispatch {
         pp::panopainter::make_legacy_canvas_stroke_main_pass_texture_dispatch(
             [&](int texture_slot) {

src/legacy_canvas_stroke_execution_services.h

@@ -127,6 +127,28 @@ struct LegacyCanvasStrokeSamplerDispatch {
     std::function<void()> unbind_mixer_sampler;
 };
 
+[[nodiscard]] inline LegacyCanvasStrokeSamplerDispatch make_legacy_canvas_stroke_sampler_dispatch(
+    std::function<void(int)> bind_brush_tip_sampler,
+    std::function<void()> unbind_brush_tip_sampler,
+    std::function<void(int)> bind_stroke_destination_sampler,
+    std::function<void()> unbind_stroke_destination_sampler,
+    std::function<void(int)> bind_pattern_sampler,
+    std::function<void()> unbind_pattern_sampler,
+    std::function<void(int)> bind_mixer_sampler,
+    std::function<void()> unbind_mixer_sampler)
+{
+    return LegacyCanvasStrokeSamplerDispatch {
+        .bind_brush_tip_sampler = std::move(bind_brush_tip_sampler),
+        .unbind_brush_tip_sampler = std::move(unbind_brush_tip_sampler),
+        .bind_stroke_destination_sampler = std::move(bind_stroke_destination_sampler),
+        .unbind_stroke_destination_sampler = std::move(unbind_stroke_destination_sampler),
+        .bind_pattern_sampler = std::move(bind_pattern_sampler),
+        .unbind_pattern_sampler = std::move(unbind_pattern_sampler),
+        .bind_mixer_sampler = std::move(bind_mixer_sampler),
+        .unbind_mixer_sampler = std::move(unbind_mixer_sampler),
+    };
+}
+
 struct LegacyCanvasStrokeFaceDirtyRequest {
     pp::renderer::Extent2D extent {};
     glm::vec4 previous_accumulated_dirty_box {};