I have two equal sized images (1 and 2) with a single layer each. I would have thought the following would add the layer from 1 to 2



but instead I get an error


PS I'm not sure about the -1 but the documentation says


and I for the life of me can't find where "GIMP_PDB_INT32" is documented (nor any of the types).

PPS The script-fu community doesn't seem to have a strong presence on stackoverflow. Is this the preferred place to ask questions?

Greetings and welcome to GC, togakangaroo.

gimp-image-get-layers returns a list of all the layers in an image. You would need to parse the list to find the single layer you're after. You might find it easier to use gimp-image-get-active-drawable for a single layer. If you've created the layer previously, you could have just saved it for use with gimp-image-insert-layer.

The last argument in gimp-image-insert-layer is the layer position in the layer stack, so it just depends on where you want it inserted, as to what that value would be.

And yes, this is a great site to get help with GIMP Scripting. There are lots of knowledgeable members here.

Thanks for the reply. Does the fact that I do



Not get the first (and in this case, only) layer? What is car returning then?

As for GIMP_PDB_INT32, I understand it means position - where can I find documentation on possible values for that (ie I just put -1 because I saw it in an example and it got me past an error, I have no idea what it actually means).

You need to use the Procedure Browser (Help>>Procedure Browser) where the help for gimp-image-insert-layer says:



And try not to use fixed numbers for the image and layer id's as it's not going to work the moment you open another image.

Kevin

Kevin is right. Try to avoid using fixed numbers for the Image ID.

To copy a layer from an image (with only one layer) to another image, you could do something like this..

From your example, where the source-image=1 and the destination-image=2


An alternate solution, using the method you were initially asking about, would go something like this..


The layer-position is the position in the layer stack: 0 to n layers, where 0 is the top layer.

'gimp-image-get-layers' returns a list containing two elements. The second element of the list is an array of layer-IDs, and the first element is the number of layer-IDs in the array.

The first element (the number of layer-IDs) is provided for those programming languages (such as C) that do not know the size of an array. Script-fu, however, is always able to determine the size of an array (or a list) without needing a separate variable to keep track of it. This means that you can safely ignore the first element of the return value.

The second element of the returned list (i.e., the actual array of layer-IDs) can be accessed by taking the 'car' of the 'cdr' of the returned list, which can be abbreviated to the 'cadr'. The PDB "int32array" is converted to a Script-fu 'vector' before it is returned, and there a few different procedures available for working with a Scheme vector. The most important of these are:

• (vector-length v) -- return the number of elements in vector 'v'
• (vector-ref v n) - return the n'th element in the vector. The parameter 'n' should be in the range 0 to one less than the number of elements in the vector (in other words, the 'vector-length'); with n=0 being the first element and n=vector-length - 1 being the last.
• (vector-set! v n x) - set the value of the n'th element to 'x'. 'x' can be of any type you want, a number, a string, a list, even another vector.
• (vector->list v) - return a list having the same elements as the vector 'v'.

So to find the first (or only) layer in an image, you could use the expression: