如何将Altair图从一条Flask路由传递到另一条？

from flask import Flask, render_template_string
import altair as alt
import base64
import io

app = Flask(__name__)

@app.route('/')
def route1():
    chart = create_chart()  # 创建Altair图表
    chart_data = get_chart_data(chart)  # 获取图表数据
    encoded_image = encode_chart(chart_data)  # 将图表数据进行编码

    return render_template_string('<img src="data:image/png;base64,{{ image }}" />', image=encoded_image)

@app.route('/other_route')
def route2():
    encoded_image = request.args.get('chart_data')  # 从查询参数获取图表数据

    return render_template_string('<img src="data:image/png;base64,{{ image }}" />', image=encoded_image)

def create_chart():
    # 创建Altair图表
    chart = alt.Chart().mark_bar().encode(x='x:Q', y='y:Q').properties(width=300, height=200)

    return chart

def get_chart_data(chart):
    # 获取图表数据
    chart_data = chart.to_dict()

    return chart_data

def encode_chart(chart_data):
    # 将图表数据进行编码为base64格式
    chart_json = json.dumps(chart_data)
    chart_bytes = chart_json.encode('utf-8')
    encoded_image = base64.b64encode(chart_bytes).decode('utf-8')

    return encoded_image

if __name__ == '__main__':
    app.run()