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 *

def finished():
    img = render.renderedImage()
    # QgsProject.instance().homePath()
    image_location = os.path.join("e:/", "render.png")
    # save the image; e.g. img.save("/Users/myuser/render.png","png")
    img.save(image_location, "png")

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

# vlayer = iface.activeLayer()
project = QgsProject.instance()
project.read(r'E:/data/1.Natural_Earth/Test.qgz')

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

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

with open("E:/data/1.Natural_Earth/Layout.qpt", 'r', encoding='utf-8') as f:
    template_content = f.read()
doc = QDomDocument()
doc.setContent(template_content)
# doc = QDomDocument("E:/data/1.Natural_Earth/Layout.qpt")
#ele = layout.writeXml(doc, QgsReadWriteContext())
#layout.readLayoutXml(ele, doc, QgsReadWriteContext())
layout.loadFromTemplate(doc, QgsReadWriteContext(), False)

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

# collection = layout.pageCollection()
# page = QgsLayoutItemPage(layout)
# page.setPageSize('A4')
# collection.addPage(page)

layoutView = QgsLayoutView()
layoutView.setPreviewModeEnabled(True)
layoutView.setContentsMargins(0, 0, 0, 0)
layoutView.setCurrentLayout(layout)

# map = QgsLayoutItemMap(layout)
# # map.zoomToExtent(layers[0].extent())
# # map.attemptResize(QgsLayoutSize(2480, 1748, QgsUnitTypes.LayoutPixels))
# 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('A5', True)

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

# layout.updateBounds()
# layout.refresh()
# page.redraw()
# collection.redraw()

exporter = QgsLayoutExporter(layout)
img_path = os.path.join("e:/", "render.png")
exporter.exportToImage(img_path, QgsLayoutExporter.ImageExportSettings())

qgs.exitQgis()