How do you manipulate an image with Python-Fu (console) in Gimp 3?

[joeyeroq]

I just installed gimp 3.0 and wanted to test the Python Console.
For example, in Gimp 2.10 you could print the layers of an image with this code in the console:

Code:

img = gimp.image_list()[0]
for layer in img.layers:
    print(layer.name)

How do you do this in Gimp 3?
   

[Ofnuts]

(03-22-2025, 10:26 PM)joeyeroq Wrote: I just installed gimp 3.0 and wanted to test the Python Console.
For example, in Gimp 2.10 you could print the layers of an image with this code in the console:

Code:

img = gimp.image_list()[0]
for layer in img.layers:
    print(layer.name)

How do you do this in Gimp 3?

Things have changed somewhat:

Code:

➤> img=Gimp.get_images()[0]
➤> for l in img.get_layers():
...     print(l.get_name())
...

In practice:

• The "PDB" thing is pretty much unused. It is only useful to call plugins
  
• Most of the code uses object methods directly: for instance, image.get_layers() instead of pdb.gimp_image_get_layers(image)
  
• But you no longer have the (rather incomplete) Python "façade" on the PDB (img.layers was such a thing, just a shortcut to pdb.gimp_image_get_layers(image)
  
• You have to learn to navigate the doc. To make it very short, 
  • there is a general object-oriented design (OOP), which is why the doc defines classes and such
    
  • but Gimp is written in C, with no built-in OOP support like you have in Python, so code examples don't look at all like OOP method calls. To make it worse C also mandates some low lever stuff (for instance if you pass an array you have to also explicitly pass its size)
    
  • but the Python interface re-introduces the OOP,  and removes the low level stuff so you can just pass a list.
    
• For instance in the code above, image.get_layers() comes from here, and doesn't look at al like the documented GimpLayer** gimp_image_get_layers (GimpImage* image)(*).
  

One of these days I'll make a tutorial on how to decode the doc, but I have 50 scripts to convert first...

(*) That coincidentally looks a lot like the 2.10 PDB call...

[joeyeroq]

(03-22-2025, 11:06 PM)Ofnuts Wrote:

(03-22-2025, 10:26 PM)joeyeroq Wrote: I just installed gimp 3.0 and wanted to test the Python Console.
For example, in Gimp 2.10 you could print the layers of an image with this code in the console:

Code:

img = gimp.image_list()[0]
for layer in img.layers:
    print(layer.name)

How do you do this in Gimp 3?

Things have changed somewhat:

Code:

➤> img=Gimp.get_images()[0]
➤> for l in img.get_layers():
...     print(l.get_name())
...

In practice:

• The "PDB" thing is pretty much unused. It is only useful to call plugins
  
• Most of the code uses object methods directly: for instance, image.get_layers() instead of pdb.gimp_image_get_layers(image)
  
• But you no longer have the (rather incomplete) Python "façade" on the PDB (img.layers was such a thing, just a shortcut to pdb.gimp_image_get_layers(image)
  
• You have to learn to navigate the doc. To make it very short, 
  • there is a general object-oriented design (OOP), which is why the doc defines classes and such
    
  • but Gimp is written in C, with no built-in OOP support like you have in Python, so code examples don't look at all like OOP method calls. To make it worse C also mandates some low lever stuff (for instance if you pass an array you have to also explicitly pass its size)
    
  • but the Python interface re-introduces the OOP,  and removes the low level stuff so you can just pass a list.
    
• For instance in the code above, image.get_layers() comes from here, and doesn't look at al like the documented GimpLayer** gimp_image_get_layers (GimpImage* image)(*).
  

One of these days I'll make a tutorial on how to decode the doc, but I have 50 scripts to convert first...

(*) That coincidentally looks a lot like the 2.10 PDB call...

Is there a difference between script and plugin in gimp 3?
Is it still possible to show a gimp python script in the menu, or does this only work for plugins in Gimp 3?
For example this simple script worked in gimp 2.10:
A file named python-fu-hello-warning.py in folder "C:\Users\USERNAME\AppData\Roaming\GIMP\2.10\plug-ins" with code:

Code:

#!/usr/bin/env python

# Hello Warning 

from gimpfu import *

def hello_warning():
     pdb.gimp_message("hello warning")

register(
    "python_fu_hello_warning",
    "Hello warning",
    "Hello warning TO ERROR CONSOLE",
    "Walter Moore",
    "Walter Moore",
    "2020",
    "Hello warning (Py)...",
    "",
    [],
    [],
    hello_warning, 
    menu="<Image>/File/HelloWarning"
)

main()

Is this still possible in Gimp 3?

[Ofnuts]

(03-23-2025, 02:36 PM)joeyeroq Wrote: Is there a difference between script and plugin in gimp 3?

Yes, but now you can also have plug-ins written in Scheme/script-fu (but as they say it's not because you can that you should...)

(03-23-2025, 02:36 PM)joeyeroq Wrote: Is it still possible to show a gimp python script in the menu, or does this only work for plugins in Gimp 3?

Python "scripts" have always been technically "plugins" (ie, they run in their own individual process)

(03-23-2025, 02:36 PM)joeyeroq Wrote: For example this simple script worked in gimp 2.10:
A file named python-fu-hello-warning.py in folder "C:\Users\USERNAME\AppData\Roaming\GIMP\2.10\plug-ins" with code:

Code:

#!/usr/bin/env python

# Hello Warning 

from gimpfu import *

def hello_warning():
     pdb.gimp_message("hello warning")

register(
    "python_fu_hello_warning",
    "Hello warning",
    "Hello warning TO ERROR CONSOLE",
    "Walter Moore",
    "Walter Moore",
    "2020",
    "Hello warning (Py)...",
    "",
    [],
    [],
    hello_warning, 
    menu="<Image>/File/HelloWarning"
)

main()

Is this still possible in Gimp 3?

Things have changed quite a lot:

• Python is Python V3 with slight syntax changes
  
• The registration process is different
  
• The API is different, you hardly use the PDB.
  

There are official tutorials.