class OpenlayersRenderer(QgsMapLayerRenderer):
def __init__(self, layer, context, webPage, layerType):
""" Initialize the object. This function is still run in the GUI thread.
Should refrain from doing any heavy work.
"""
QgsMapLayerRenderer.__init__(self, layer.id())
self.context = context
self.controller = OpenlayersController(None,
context, webPage, layerType)
self.loop = None
def render(self):
""" do the rendering. This function is called in the worker thread """
debug("[WORKER THREAD] Calling request() asynchronously", 3)
QMetaObject.invokeMethod(self.controller, "request")
# setup a timer that checks whether the rendering has not been stopped
# in the meanwhile
timer = QTimer()
timer.setInterval(50)
timer.timeout.connect(self.onTimeout)
timer.start()
debug("[WORKER THREAD] Waiting for the async request to complete", 3)
self.loop = QEventLoop()
self.controller.finished.connect(self.loop.exit)
self.loop.exec_()
debug("[WORKER THREAD] Async request finished", 3)
painter = self.context.painter()
painter.drawImage(0, 0, self.controller.img)
return True
def onTimeout(self):
""" periodically check whether the rendering should not be stopped """
if self.context.renderingStopped():
debug("[WORKER THREAD] Cancelling rendering", 3)
self.loop.exit()
class OpenlayersRenderer(QgsMapLayerRenderer):
def __init__(self, layer, context, webPage, layerType):
""" Initialize the object. This function is still run in the GUI thread.
Should refrain from doing any heavy work.
"""
QgsMapLayerRenderer.__init__(self, layer.id())
self.context = context
self.controller = OpenlayersController(None, context, webPage,
layerType)
self.loop = None
def render(self):
""" do the rendering. This function is called in the worker thread """
debug("[WORKER THREAD] Calling request() asynchronously", 3)
QMetaObject.invokeMethod(self.controller, "request")
# setup a timer that checks whether the rendering has not been stopped
# in the meanwhile
timer = QTimer()
timer.setInterval(50)
timer.timeout.connect(self.onTimeout)
timer.start()
debug("[WORKER THREAD] Waiting for the async request to complete", 3)
self.loop = QEventLoop()
self.controller.finished.connect(self.loop.exit)
self.loop.exec_()
debug("[WORKER THREAD] Async request finished", 3)
painter = self.context.painter()
painter.drawImage(0, 0, self.controller.img)
return True
def onTimeout(self):
""" periodically check whether the rendering should not be stopped """
if self.context.renderingStopped():
debug("[WORKER THREAD] Cancelling rendering", 3)
self.loop.exit()
def _forcibly_terminate_loop(loop: QtCore.QEventLoop):
log("Forcibly ending event loop...")
loop.exit(1)