[GIS] How to refresh QgsMapcanvas

pythonqgis

I am using Qgis 1.7 and I want to refresh the mapcanvas
so I am using refresh() function of QgsMapcanvas class
and Nothing is happening to the Map Canvas.
I am using Python for customizing

Best Answer

I use

self.iface.mapCanvas().refresh()

in Time Manager plugin and it works. You can check the source on Github.

Related Solutions

QGIS 2.6 – mapCanvas().refresh() Not Working in QGIS 2.6

It may very well be a bug as I also cannot get the canvas to refresh. You can try the following as a workaround:

myLayer.triggerRepaint()

To refresh all layers following function can be used:

def refresh_layers(self):
    for layer in qgis.utils.iface.mapCanvas().layers():
        layer.triggerRepaint()

QGIS – Difference Between iface.mapCanvas and QgsMapCanvas

On the one hand, QgsMapCanvas is a class. You can always create new canvas objects from it (as you did already in your second attempt).

On the other hand, iface.mapCanvas() is an instance, an object of the class QgsMapCanvas. iface.mapCanvas() is initialized when you load QGIS app with GUI (Python should be enabled to use it), and refers to the main canvas you see in QGIS GUI.

In a standalone app, iface is not initialized. QGIS app has no default canvas, and you are responsible for adding one to your app (which is optional, as you can have an app with no canvas). That's why you cannot call iface.mapCanvas() when working on a standalone app.

Best Answer

Related Solutions

QGIS 2.6 – mapCanvas().refresh() Not Working in QGIS 2.6

QGIS – Difference Between iface.mapCanvas and QgsMapCanvas

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