Python_fu plugin won't load in gimp

Question

I am trying to write a gimp plugin using python_fu. I want it to take lots of identically sized layers and put them in a vertical line. This would be used for opening pdf files where each of the pages occupies one layer, and the plugin would put them in a line. When I run the plugin though, nothing appears in the menu. When I comment out the line with an asterisk above it the plugin loads in the menu.

%UserProfile%\.gimp-2.8\plug-ins\Array.py

from gimpfu import *

def plugin_main(timg, tdrawable, widthNum, heightNum):

    layers = gimp-image-get-layers(timg) #<< Gets a list of all the layers

    #Sets the WIDTH and HEIGHT to the size of the first image
    WIDTH = layers[0].width
    HEIGHT = layers[0].height

    #Loops through all layers and moves them
    for i in range(layers.length):
        location = float((i+1)*HEIGHT)
        #*****
        transformedimage = gimp-item-transform-2d(layers[i], 0.0, 0.0, 1.0, 1.0, 0.0, location) #<< When I comment this line out the plugin loads

    gimp-image-resize-to-layers() #<< Resizes the image to fit the moved layers

register(
        "python_fu_array",
        "Sets out your layers as tiles",
        "Sets out your layers as tiles",
        "author",
        "author",
        "2016",
        "<Image>/Image/Array",
        "RGB*, GRAY*",
        [],
        [],
        plugin_main)

main()

score 2 · Answer 1 · answered Nov 04 '16 at 12:23

2

Have a look at some existing Python-based plug-ins, for example https://git.gnome.org/browse/gimp/tree/plug-ins/pygimp/plug-ins/py-slice.py

Notice how some procedures are called there, for example in line 168: https://git.gnome.org/browse/gimp/tree/plug-ins/pygimp/plug-ins/py-slice.py#n168

temp_image = pdb.gimp_image_new (...)

There are two differences to your code:

the pdb prefix
underscores instead of hyphens/minuses

Change your plug-in to do it like this, and you'll get a few steps further.

answered Nov 04 '16 at 12:23

Michael Schumacher

528
8
16

1

ust to be totally clear: `gimp-item-transform-2d` in Python would mean a series of subtractions - not a variable name. GIMP api names in Python replace the `-` for `_`. And they are in the `pdb` namespace - so - change your problematic line for to contain `pdb.gimp_item_transform-2d(...)` instead of the current form. – jsbueno Nov 04 '16 at 13:54

score 0 · Answer 2 · answered Nov 04 '16 at 13:22

In addition to Michael's remark, the Python-fu interface defines python-style objects and classes for many Gimp concepts so you can very often avoid the pdb.* functions. For instance to iterate the image layers:

Your code: layers = gimp-image-get-layers(timg) #<< Gets a list of all the layers

#Sets the WIDTH and HEIGHT to the size of the first image
WIDTH = layers[0].width
HEIGHT = layers[0].height

#Loops through all layers and moves them
for i in range(layers.length):

Better code:

# better use the image height/width, layer h/w can be different
width=image.width
height=image.height

for position,layer in enumerate(image.layers):
    # etc....

We all do errors. You can weed out your biggest syntax blunders without even starting Gimp, by calling Python on your script in a command prompt. If it goes as far as complaining about gimpfu, you will stand a good chance that it will run under Gimp.

For good beginner Python advice: www.python-forum.io
For good beginner Gimp Python advice: www.gimp-forum.net

just another remark - this way to interact layers is no longer good, as it does not take layer groups into account. — jsbueno, Nov 04 '16 at 13:54
I wrote some post somewhere on SE about how to go into layer groups. — Michael Schumacher, Nov 04 '16 at 13:56
@jsbueno in the general case yes, but it can be good enough in many cases. The whole script looks like it expects a specific layer setup anyway. — xenoid, Nov 04 '16 at 20:37

Python_fu plugin won't load in gimp

2 Answers2