Method DrawGraph

Engine/Editor/Source/UI/Tools/NodeGraph/EdNodeGraph.cpp:282–930

        {
            NodeEditor::PushStyleVar(NodeEditor::StyleVar_PivotAlignment, ImVec2(0.5f, 0.5f));
            NodeEditor::PushStyleVar(NodeEditor::StyleVar_PivotSize,      ImVec2(0, 0));
            NodeEditor::PushStyleVar(NodeEditor::StyleVar_PinRadius,      DotRadius);
            NodeEditor::BeginPin(OutputPin->GetPinGUID(), NodeEditor::PinKind::Output);
            NodeEditor::PinPivotRect(Center, Center);
            NodeEditor::PinRect(OutputRectMin, OutputRectMax);
            NodeEditor::EndPin();
            NodeEditor::PopStyleVar(3);
        }

        ImGui::PopID();
        NodeEditor::EndNode();

        NodeEditor::PopStyleColor(2);
        NodeEditor::PopStyleVar(3);

        // Painted on the node background list, so it sits behind wires but above the node background.
        if (ImDrawList* DrawList = NodeEditor::GetNodeBackgroundDrawList(Node->GetNodeID()))
        {
            DrawList->AddCircleFilled(Center, DotRadius + 1.5f, DotShadow, 16);
            DrawList->AddCircleFilled(Center, DotRadius,        DotColor,  16);
        }
    }

    CEdGraphNode* CEdNodeGraph::InsertRerouteOnLink(CEdNodeGraphPin* OutputPin, CEdNodeGraphPin* InputPin, ImVec2 CanvasPos)
    {
        if (OutputPin == nullptr || InputPin == nullptr)
        {
            return nullptr;
        }

        CClass* RerouteClass = GetRerouteNodeClass();
        if (RerouteClass == nullptr)
        {
            return nullptr;
        }

        CEdGraphNode* RerouteNode = CreateNode(RerouteClass);
        if (RerouteNode == nullptr)
        {
            return nullptr;
        }

        CEdNodeGraphPin* RerouteIn  = RerouteNode->GetInputPins().empty()  ? nullptr : RerouteNode->GetInputPins()[0].Get();
        CEdNodeGraphPin* RerouteOut = RerouteNode->GetOutputPins().empty() ? nullptr : RerouteNode->GetOutputPins()[0].Get();
        if (RerouteIn == nullptr || RerouteOut == nullptr)
        {
            return RerouteNode;
        }

        // Break the original wire and rebuild it as Source -> RerouteIn, RerouteOut -> Target.
        OutputPin->DisconnectFrom(InputPin);

        OutputPin->AddConnection(RerouteIn);
        RerouteIn->AddConnection(OutputPin);

        RerouteOut->AddConnection(InputPin);
        InputPin->AddConnection(RerouteOut);