Restrict when point labels are displayed using PyQGIS

Question

I have a number of points that I'm visualising on a points layer, and labelling using PyQGIS. Unfortunately when zoomed out too much, the resultant map appears a mess of labels.

Can I use PyQGIS to specify that labels should only appear in certain circumstances? I was hoping to test with displaying labels:

• Only if there are less than a certain number of points currently being rendered/visible on the screen (e.g. 50) - I suspect this is the best solution
• Failing that, set to only display labels if the scale is less than 1:5000*

Is it possible to do either of the above using PyQGIS?

Edit: * I can do this manually in QGIS by enabling: Rendering > Label options > Scale dependent visibility and setting min/max scale values

Current code is along the lines of:

layer_settings = QgsPalLayerSettings()
layer_settings.drawLabels = True
layer_settings.fieldName = "Vehicle"
layer_settings.isExpression = True

label_settings = QgsVectorLayerSimpleLabeling(layer_settings)

points_layer.setLabeling(label_settings)
points_layer.setLabelsEnabled(True)

Answer 1

Use scaleVisibility and minimumScale attributes of QgsPalLayerSettings class.

# other stuff

layer_settings.scaleVisibility = True
layer_settings.minimumScale = 5000 # -> 1:5.000

#...

Also you can set maximum scale using layer_settings.maximumScale = 5000