I did the following

pdb.file_jpeg_save(image, drawable, filename, raw_filename, quality, smoothing, optimize, progressive, ...))
pdb.gimp_image_add_layer(image, imagLayer, 0)
pdb.file_jpeg_save(image, drawable, filename, raw_filename, quality, smoothing, optimize, progressive, ...))

The first save ran without any issue but after I added a layer, I am unable to save it again. I got a message:

Calling error for procedure 'file-jpeg-save':
Procedure 'file-jpeg-save' has been called with an invalid ID for argument 'drawable'. Most likely a plug-in is trying to work on a layer that doesn't exist any longer.

It sounds like I need a new drawable after added a new layer,

But how do I do that?

The file-*-save procedure do not save the image, they save a layer. What happened in your case is likely that the initial layer is no more. If you merged things (gimp_image_flatten(), gimp_image_merge_down() and a few others) the result is a new layer, but the call returns the layer created. So you just have to keep that returned value.

If your image still has several layers at the end, instead of flattening you can also use gimp_layer_new_from_visible() and save the returned layer.

You need to create a new layer first before you add or insert the layer.

Thank you for the response.

I guessed that much. In fact, after the post, I did a pdb.gimp_image_merge_down to get a new layer but pdb.file_jpeg_save doesn't take layers as a parameter.

pdb.file_jpeg_save(image, drawable, filename, raw_filename, quality, smoothing, optimize, progressive, comment, subsmp, baseline, restart, dct)

I tried

pdb.gimp_image_set_active_layer(image, newLayer)

and that doesn't do anything.


So what do I do with the returned layer?

to get the layer again that you merged. Are you using GIMP's PPB or PDB? The procedure Browser is your best friend!

I have the new_layer returned by several procedures I tried. That's not the problem.

What do I do with it? pdb.file_jpeg_save doesn't accept layer as a parameter.

I am having trouble communicating. We are going back and forth without progress. You said " can be used for the save". My point is "pdb.file_jpeg_save doesn't accept layer as a parameter". So, if it doesn't accept layer as a parameter, how does it "used for the save"? It accepts drawable as parameter but not layer.

Of course it does. A layer is a drawable (a drawable is a layer, a channel or a mask), so the "drawable" parameter should be the layer returned by pdb.gimp_image_merge_down().

I think you should read the GIMP Python Documentation

LOFL! Is it that obvious? Great help! I completed my first plugin. I am very comfortable with Python. I just need to get familiar with GIMP specific details.

Thanks for all the help, folks.

Then you should have found this:

>>> layer=gimp.image_list()[0].active_layer
>>> layer.__class__.__mro__
(<type 'gimp.Layer'>, <type 'gimp.Drawable'>, <type 'gimp.Item'>, <type 'object'>)

Alright. You got me stumped. I know syntactically what these statements are but how would they have helped me realize "Drawable" means I can pass the "layer" to it?

For me as a newbie, I thought it's a typo for "Drawtable"!!!

When I started scripting and got stuck on the 'eccentricities' of Gimp I found that looking at other people's code was a big help.

Well, if you know Python, you know some OOP. Types within types within types. If I tell you something takes a Collection, but you have a Set, you'll wonder if the Set is a Collection. In any case this isn't civil engineering, the cost of trying something is nearly zero. And since you already had case that worked, did you try to check the type of what was passed in that call?