import os
import math
from qgis.core import *
from qgis.gui import *
from qgis.PyQt.QtGui import *
from qgis.PyQt.QtCore import *
from qgis.PyQt.QtWidgets import *
from qgis.PyQt.QtXml import *

QgsApplication.setPrefixPath(r"C:/Program Files/QGIS 3.16/bin", True)
qgs = QgsApplication([], True)
qgs.initQgis()

project = QgsProject.instance()
project.read(r'E:/terrait/TianJin/LFServer/QGIS/Test.qgz')
print("FileName: " + project.fileName())

# layers = project.mapLayers().values()
# root = project.layerTreeRoot()

# layout = QgsPrintLayout(project)
layout = QgsLayout(project)
# layout.initializeDefaults()

with open(r"E:/terrait/TianJin/LFServer/QGIS/Template.qpt", 'r', encoding='utf-8') as f:
    template_content = f.read()
doc = QDomDocument()
doc.setContent(template_content)
layout.loadFromTemplate(doc, QgsReadWriteContext(), True)

map = layout.itemById(r'地图')
print(math.ceil(map.scale()))

exporter = QgsLayoutExporter(layout)
img_path = os.path.join(r"E:/terrait/TianJin/LFServer/QGIS", "render.png")
exporter.exportToImage(img_path, QgsLayoutExporter.ImageExportSettings())

qgs.exitQgis()