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()
Example #3
0
def _forcibly_terminate_loop(loop: QtCore.QEventLoop):
    log("Forcibly ending event loop...")
    loop.exit(1)