How to duplicate a master with Python?

Scripting
1

What is the scripting equivalent of “Duplicate Selected” in the app Masters pane “+” menu?
When I access font.masters[0], there is no duplicate() function and copy() gets me a master with no layers.
Thanks!

2

Does this help?

Also check out the Method Reporter mekkablue script, you can search all available methods of the GSFontMaster class.

3

Thanks, but this seems to only get me partway there. The newly created master has a layer, but the new layer has no paths in it.

In the app’s UI, “Duplicate master” creates a new master with duplicated layers and duplicated paths within them. I can probably loop to copy existing paths into the new layer for each glyph, but wondering if I’m missing something here. Thanks again.

4

I seem to get copied shapes on my new layer by invoking the suggested copy expression from the scripting doc page:

def duplicateMaster(font, originalMaster):
	masterCopy = originalMaster.copy()
	font.masters.append(masterCopy)
	font.copyInfoFrom_sourceFontMasterID_targetFontMasterID_(font, master.id, masterCopy.id)
	
	for glyph in font.glyphs:
		layer = glyph.layers[master.id]
		layerCopy = glyph.layers[masterCopy.id]
		layerCopy.width = layer.width
		layerCopy.shapes = copy.copy(layer.shapes)
	
	return masterCopy

But I get strange behavior in the editing UI when I do this with respect to where the curve points are. I think something is still “linking” the paths between the layers despite them having been copied by the font.copyInfoFrom_sourceFontMasterID_targetFontMasterID_ function?

Note that I also have to set the new layer’s width to match the original layer width. But I still don’t know exactly what else I’m missing out on here.

It would be nice to have a documented/standard recipe that performs the same behavior that I get from using the app UI’s “duplicate” master feature. Thanks.

5

There is actually a better API:

font.addFontMasterAndContent_(originalMaster)
1 Like
6

this copies the shapes object (the list containing the shapes), but not the shapes. Use copy.deepcopy(layer.shapes).

2 Likes
7

Ah, thank you Georg! This works and avoids the weird UI glitching I was seeing (which I can now guess at the cause of). I recommend updating the Python doc page here to use deepcopy instead for these examples. I was using the suggestion shown:

# copy shapes from another layer
import copy
layer.shapes = copy.copy(anotherlayer.shapes)

Thanks.