protected AttributedVertex getBasicBlockVertex(AttributedGraph graph, CodeBlock bb)
			throws CancelledException {

		String vertexId = getVertexId(bb);
		AttributedVertex vertex = graph.getVertex(vertexId);

		if (vertex != null) {
			return vertex;
		}

		String vertexName = bb.getName();
		vertex = graph.addVertex(vertexId, vertexName);

		// add attributes for this vertex -
		setVertexAttributes(vertex, bb, vertexName.equals(vertexId) ? false : isEntryNode(bb));

		if (showCode) {
			addSymbolAttribute(vertex, bb);
			addCodeAttribute(vertex, bb);
		}

		return vertex;
	}
Set the maximum number of code lines which will be used per block when
showCode is enabled.
@param maxLines maximum number of code lines
Ghidra/Features/ProgramGraph/src/main/java/ghidra/graph/program/BlockGraphTask.java