我已经为我的QGIS 2.8.1
编写了一个代码,该代码可以成功拍摄一个形状文件的屏幕截图,但不幸的是,当我尝试使用多个shapefile时,该代码不起作用。
因此,基本上,如果我将下面代码中的allFiles = ["C:/Shapefiles/Map_00721.shp"]
替换为allFiles = ["C:/Shapefiles/Map_00721.shp", "C:/Shapefiles/Map_00711.shp", "C:/Shapefiles/Map_00731.shp", "C:/Shapefiles/Map_00791.shp", "C:/Shapefiles/Map_00221.shp"]
,循环将遍历数组,而无需等待渲染和快照过程发生。
我尝试在下面的代码中使用time.sleep
,但是它也停止了shapefile的呈现,并且结果不符合预期。
import ogr,os
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from qgis.core import *
import qgis.utils
import glob
from time import sleep
import math
import processing
from processing.core.Processing import Processing
from PyQt4.QtCore import QTimer
Processing.initialize()
Processing.updateAlgsList()
OutputFileName = "ABC" # Temprory global placeholder for filename
canvas = iface.mapCanvas()
def startstuffs():
qgis.utils.iface.zoomToActiveLayer() #Zoom to Layer
scale=canvas.scale() # Get current Scale
scale = scale * 1.5
canvas.zoomScale(scale) # Zoomout a bit
QTimer.singleShot(2000,saveImg) # Jump to save img
def saveImg():
qgis.utils.iface.mapCanvas().saveAsImage(OutputFileName)
QgsMapLayerRegistry.instance().removeAllMapLayers()
#Add array of address below
allFiles = ["C:/Shapefiles/Map_00721.shp"]
filesLen = len(allFiles)
TexLayer = "C:/US_County_NAD27.shp"
for lop in range(filesLen):
currentShpFile = allFiles[lop]
currentShpFileName = currentShpFile.strip("C:/Shapefiles/")
OutputFileName = "C:/ImageOut/" + currentShpFileName + ".png"
wb = QgsVectorLayer(currentShpFile, currentShpFileName, 'ogr')
wbTex = QgsVectorLayer(TexLayer, 'CountyGrid', 'ogr')
QgsMapLayerRegistry.instance().addMapLayer(wb) # Add the shapefile
QgsMapLayerRegistry.instance().addMapLayer(wbTex) # Add the county shapefile
qgis.utils.iface.setActiveLayer(wb) # Makes wb as active shapefile
QTimer.singleShot(3000,startstuffs) #This start stuffs
print "Done!"
答案 0 :(得分:2)
避免使用time.sleep()
,因为那样会完全停止整个程序。而是使用processEvents()
,它可以让您的程序在后台呈现。
import time
def spin(seconds):
"""Pause for set amount of seconds, replaces time.sleep so program doesn't stall"""
time_end = time.time() + seconds
while time.time() < time_end:
QtGui.QApplication.processEvents()
此方法应可以快速修复,但从长远来看,可能会产生难以跟踪的问题。最好将带有事件循环的QTimer用于永久解决方案。