QwtPlot: fixed event mgt + removed unnecessary QEvent.LayoutRequest

(caused high CPU usage with guiqwt.ImageWidget)

Author: PierreRaybaut

qwt/plot.py

@@ -1022,12 +1022,11 @@ def setCanvas(self, canvas):
                 canvas.show()
 
     def event(self, event):
-        ok = QFrame.event(self, event)
         if event.type() == QEvent.LayoutRequest:
             self.updateLayout()
         elif event.type() == QEvent.PolishRequest:
             self.replot()
-        return ok
+        return QFrame.event(self, event)
 
     def eventFilter(self, obj, event):
         if obj is self.__data.canvas:

qwt/scale_widget.py

@@ -509,14 +509,22 @@ def layoutScale(self, update_geometry=True):
 
         if update_geometry:
             self.updateGeometry()
-            #  for some reason updateGeometry does not send a LayoutRequest
-            #  event when the parent is not visible and has no layout
-            widget = self.parentWidget()
-            if widget and not widget.isVisible() and widget.layout() is None:
-                if widget.testAttribute(Qt.WA_WState_Polished):
-                    QApplication.postEvent(
-                        self.parentWidget(), QEvent(QEvent.LayoutRequest)
-                    )
+
+            # The following was removed because it caused a high CPU usage 
+            # in guiqwt.ImageWidget. The origin of these lines was an 
+            # attempt to transpose PythonQwt from Qwt 6.1.2 to Qwt 6.1.5.
+
+            #--> Begin of removed lines <--------------------------------------
+            # #  for some reason updateGeometry does not send a LayoutRequest
+            # #  event when the parent is not visible and has no layout
+            # widget = self.parentWidget()
+            # if widget and not widget.isVisible() and widget.layout() is None:
+            #     if widget.testAttribute(Qt.WA_WState_Polished):
+            #         QApplication.postEvent(
+            #             self.parentWidget(), QEvent(QEvent.LayoutRequest)
+            #         )
+            #--> End of removed lines <----------------------------------------
+
             self.update()
 
     def drawColorBar(self, painter, rect):