import os
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 = QgsLayoutItemMap(layout)
# # map.zoomToExtent(layers[0].extent())
# layout.addItem(map)

collection = layout.pageCollection()
collection.deletePage(0)
page = QgsLayoutItemPage(layout)
page.setPageSize('A5', True)
collection.addPage(page)
collection.redraw()

# collection = layout.pageCollection()
# page = collection.page(0)
# # QgsUnitTypes.LayoutCentimeters
# size = QgsLayoutSize(2480, 1748, QgsUnitTypes.LayoutPixels)
# page.setPageSize('A3', True)

# imgSetting = QgsLayoutExporter.ImageExportSettings()
# imgSetting.imageSize.width = 4096
# imgSetting.imageSize.heigth = 3507

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

qgs.exitQgis()