实时变化的流程图
import streamlit as st
import graphviz
if 'num' not in st.session_state:
st.session_state.num = "1"
def update2():
st.session_state.num = "2"
def update3():
st.session_state.num = "3"
st.write(st.session_state.num)
st.button("Perform calculation 2", on_click=update2, key='key_2')
st.button("Perform calculation 3", on_click=update3, key='key_3')
graph= graphviz.Digraph(graph_attr={'rankdir':'LR'})
graph.edge(f'3', '12 ', label='3*4')
graph.edge(f'4', '12 ', label='4*3')
graph.edge('12 ', '12', label='max(0,12)')
graph.edge('12', '60', label='12*5')
graph.edge(st.session_state.num, '60', label='5*12')
graph.edge('60', '1600', label='(100 - 60)**2')
#red arrows
graph.edge('1600', '60', label='2*(100 - 60)=80', color='red')
graph.edge('60', '12', label='5*80=400', color='red',)
graph.edge('60', st.session_state.num, label='12*80=960', color='red')
graph.edge('12', '12 ', label='1*400=400', color='red')
graph.edge('12 ', '3', label='400*4=1600', color='red')
graph.edge('12 ', '4', label='400*3=1200', color='red')
st.graphviz_chart(graph)