Extract draw merge branch dispatch object helper

src/canvas.cpp

@@ -514,6 +514,16 @@ static void execute_canvas_draw_merge_plane_final_composite(
     bool draw_checkerboard,
     bool use_blend);
 
+static pp::panopainter::LegacyCanvasDrawMergeLayerCompositeExecution make_canvas_draw_merge_branch_dispatch(
+    Canvas& canvas,
+    int plane_index,
+    int layer_index,
+    const std::shared_ptr<Layer>& layer,
+    const Brush& brush,
+    const glm::mat4& ortho,
+    bool copy_blend_destination,
+    bool draw_checkerboard);
+
 static void execute_canvas_draw_merge_branch_body(
     Canvas& canvas,
     int plane_index,
@@ -535,7 +545,28 @@ static void execute_canvas_draw_merge_branch_body(
         canvas.m_current_stroke && canvas.m_current_mode == kCanvasMode::Erase && canvas.m_show_tmp && canvas.m_current_layer_idx == layer_index,
         canvas.m_current_stroke && canvas.m_show_tmp && canvas.m_current_layer_idx == layer_index,
         use_blend,
-        pp::panopainter::LegacyCanvasDrawMergeLayerCompositeExecution {
+        make_canvas_draw_merge_branch_dispatch(
+            canvas,
+            plane_index,
+            layer_index,
+            layer,
+            brush,
+            ortho,
+            copy_blend_destination,
+            draw_checkerboard));
+}
+
+static pp::panopainter::LegacyCanvasDrawMergeLayerCompositeExecution make_canvas_draw_merge_branch_dispatch(
+    Canvas& canvas,
+    int plane_index,
+    int layer_index,
+    const std::shared_ptr<Layer>& layer,
+    const Brush& brush,
+    const glm::mat4& ortho,
+    bool copy_blend_destination,
+    bool draw_checkerboard)
+{
+    return pp::panopainter::LegacyCanvasDrawMergeLayerCompositeExecution {
         .execute_temporary_erase = [&] {
             execute_canvas_draw_merge_temporary_erase_dispatch(
                 canvas,
@@ -583,7 +614,7 @@ static void execute_canvas_draw_merge_branch_body(
                 make_canvas_draw_merge_layer_blend_dispatch(
                     canvas));
         },
-        });
+    };
 }
 
 static auto make_canvas_draw_merge_temporary_erase_dispatch(