Readme update

README.md

@@ -61,9 +61,11 @@ You can also do things like create a backing fill to make sure the resist develo
 
 ## 0.8.9 (July 20, 2018)
 ### New features
-- The addition of the argument `max_cellname_length` added to `D.write_gds()`.  It is `28` by default, to guarantee maximum compatibility with other GDS software.
+- The addition of the argument `max_cellname_length` added to `D.write_gds()`.  It is `28` by default, to guarantee maximum compatibility with GDS specifications.
 - New documentation backend (contribution thanks to Alex Tait @atait)
-
+- Added `D.remap_layers()` which allows you to to move all polygons contained on a layer within your Device to another layer. See tutorial for details
+- Added `D.remove_layers()` which lets you remove all polygon geometry (optionally including labels) from a Device on the specified layers
+
 ### Bugfixes
 - Further fixes to `D.write_gds()` for rare edge cases
 

phidl/phidl_tutorial_example.py

@@ -458,21 +458,40 @@ def waveguide(width = 10, height = 1):
 E = pg.import_gds(filename = 'MyLayerSetPreview.gds')
 qp(E)
 
-# Now say we only wanted to get layers 2 and 3 from the file.  We can specify
-# a list of layers using the `layers` argument
-E2 = pg.import_gds(filename = 'MyLayerSetPreview.gds',
-                   layers = [4, 5], flatten = True)
-qp(E2)
 
-# We can also use the `layers` argument to map layers arbitrarily. Say we
-# wanted to move shapes on layer 4 to layer 5, but leave layer 6
-# on layer 6.  We can map layers 4->5, 6->6, and ignore layer 5  by passing a 
-# dict to the `layers` argument
-E3 = pg.import_gds(filename = 'MyLayerSetPreview.gds',
-                   layers = {4: 5, 6:6})
-qp(E3)
+# Similarly, we can import the same file but flatten the entire cell
+# heirarchy
+E2 = pg.import_gds(filename = 'MyLayerSetPreview.gds', flatten = True)
 
+#==============================================================================
+# Removing  layers
+#==============================================================================
+# Now say we only wanted to get layers 4 and 5 from an imported.  We can remove
+# the unwanted layers using the remove_layers() function
+D = pg.import_gds(filename = 'MyLayerSetPreview.gds')
+
+# We set "invert_selection" to True so that all layers EXCEPT 4 and 5
+# are removed
+D.remove_layers(layers = [4,5], invert_selection = True)
+qp(D)
+
+# If we later decide that we actually don't want layer 4, as well, we
+# can leave the `invert_selection` argument blank
+D.remove_layers(layers = [4])
+qp(D)
 
+#==============================================================================
+# Remapping layers
+#==============================================================================
+# Let's import our layerset preview again
+D = pg.import_gds(filename = 'MyLayerSetPreview.gds')
+
+# We can use the remap_layers() function to map layers arbitrarily. Say we
+# wanted to move shapes on layer 5 to layer 99, and layer 6 to layer 77
+# but leave the other layers alone.  We can map layers 5->99, 6->77, and leave
+# any other layers alone by passing a dict to the `layermap` argument
+D.remap_layers(layermap = {5: 99, 6:77})
+qp(D)