New Constraint: Layer Permutations

[monyarm]

I'd like to request a constraint to export layer group permutations,
for example if i have the structure

a
-1
-2
b
-1
-2

I'd like to get a1b1.png ,a1b2.png ,a2b1.png and a2b2.png.
Would such a feature be possible?

[khalim19]

Hi, could you elaborate on how the layers should be combined? Not sure if I understand - I'm assuming that for a1b1.png, a1 is the background/foreground?

Either way, I'll think about it, although this seems to be a candidate for a completely separate plug-in that creates these permutations and then Export Layers would be used to export all the created combinations.

[monyarm]

a and b are layer groups, while the digits are the actual layers in those groups.

[khalim19]

So when I take 1 from a and 1 from b, then a single layer a1b1 should be produced and exported? My question is, how they should be combined together, e.g. "first insert a1, then insert b1, then merge these two layers into one".

[monyarm]

The way they're ordered and combined would be how gimp normally does layers.
And you wouldn't be creating a layer a1b1, but rather would be disabling all layers except a1 and b1, and exporting that.

[khalim19]

You could try inserting the following code into Filters -> Python-Fu -> Console:

import itertools
import os


def get_layers_from_group(group):
    layers = []
    inner_groups = [group]
    
    while inner_groups:
        inner_group = inner_groups[0]
        del inner_groups[0]
        for child in inner_group.children:
            if isinstance(child, gimp.GroupLayer):
                inner_groups.append(child)
            else:
                layers.append(child)
    
    return layers


# output directory of your choosing
output_dirpath = r'C:\Users\khalim\Downloads\test'

# This assumes that the first image opened is the image you want to export layers from.
image = gimp.image_list()[0]

groups = image.layers
layers_per_group = []

for group in groups:
    layers_per_group.append(get_layers_from_group(group))

layer_visible_pairs = list(itertools.product(*layers_per_group))

for layer1, layer2 in layer_visible_pairs:
    for layer in layers:
        layer.visible = False
    
    layer1.visible = True
    layer2.visible = True
    
    image_copy = pdb.gimp_image_duplicate(image)
    final_layer = pdb.gimp_image_merge_visible_layers(image_copy, 0)
    
    filename = '-'.join([layer1.name, layer2.name]) + '.png'
    
    pdb.file_png_save(image_copy, final_layer, os.path.join(output_dirpath, filename), filename, 0, 9, 0, 0, 0, 0, 0)
    
    pdb.gimp_image_delete(image_copy)

This actually does not use Export Layers at all. If you still need to leverage additional features from Export Layers (such as custom procedures), I think the only way to achieve this is to:

1. move groups A and B under a single layer group
2. in Export Layers, uncheck Include layers and check Include layer groups and Only top-level layers
3. save settings (Settings -> Save Settings).
4. in the code above, replace the pdb.file_png_save(... line with

pdb.plug_in_export_layers(image, 'png', output_dirpath, None, 0)