Removing colour bands in PyQGIS

Question

How do I remove unwanted colour from the palette from a Raster via the PyQGIS API? For example, remove black from the palette. It works manually within Layer Properties -> Symbology -> Band Rendering -> Paletted.

I have looked in 3.10 API docs but can't see how this is done.

https://qgis.org/pyqgis/3.10/core/QgsPalLayerSettings.html

Answer 1

• Get palette values

  classes = layer.renderer().classes()
  

• Remove any class

  del classes[0] # removes the first item
  

• Set layer renderer

  renderer = QgsPalettedRasterRenderer(provider, band, classes)
  layer.setRenderer(renderer)
  

Minimal sample code:

layer = iface.activeLayer()

renderer = layer.renderer()

provider = layer.dataProvider()
band = renderer.band()    
classes = renderer.classes()
del classes[0]  # remove the first color

renderer = QgsPalettedRasterRenderer(provider, band, classes)

layer.setRenderer(renderer)
layer.triggerRepaint()