[Qgis-user] Measuring Map Rendering Time using PyQGIS

[Alexandre Neto]

Hi,

I am looking for a way to audit a QGIS projects in terms of layer rendering
time.

I was able to measuring the rendering every time I refresh the the map
canvas, change layers or change extent, using the following code (inspired
by Anita code):

from datetime import datetime

def get_time():
    t1 = datetime.now()
    print('Rendering time:',t1-t0, 'seconds')

def reset_time():
    global t0
    t0 = datetime.now()

canvas = iface.mapCanvas()
canvas.mapCanvasRefreshed.connect(get_time)
canvas.extentsChanged.connect(reset_time)
canvas.layersChanged.connect(reset_time)

Now, I wanted to programmatically zoom in, zoom out, enable and disable
layers, etc... but If I give two or more of these commands together, each
command won't wait for the other to finish rendering, therefore I am unable
to measure the time.

For example:
iface.actionZoomFullExtent()
canvas.zoomByFactor(0.5)

Only returns the time for the last zoom to render.

I have tried using time.wait() but that stops the rendering all together.

Thanks,

Alexandre Neto
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