[Gimp-user] batch mode debugging

[saulgoode at flashingtwelve.brickfilms.com]

Quoting Milos Prudek <prudek at bvx.cz>:

>> It is my understanding that ALL Script-fus are run non-interactively.
>
> script-fu-fuzzy-border can run interactively. It is available in
> Right-click/Script-Fu/Decor/ menu in GIMP. It asks interactively for its
> parameters. Is it an interactive run?

The dialogs for Script-fus are generated and handled by the GIMP.  
Unlike plug-ins and other scripting languages, there is nothing that a  
Script-fu script has to do to interact with the user -- the parameters  
are defined by the dialogs before the 'script-fu-*' function is  
evaluated. This is why the function is considered non-interactive.

>> not have the same 'drawable' ID as before the flattening. If you do a
>> second 'gimp-image-get-active layer' after flattening then you will be
>> passing the proper 'drawable' ID to the save plug-in.
>
> OK. I tried to implement your idea:
>
>  (define (fuzzy-border-single filename)
>    (let* ((image (car (gimp-file-load RUN-NONINTERACTIVE filename filename)))
>           (drawable (car (gimp-image-get-active-layer image))))
>
>  (script-fu-fuzzy-border image drawable '(255 255
> 255) 120 TRUE 9 FALSE 0 FALSE TRUE)
>      (set! (drawable (car (gimp-image-get-active-layer image))))
>      (gimp-file-save RUN-NONINTERACTIVE image drawable filename filename)
>      (gimp-image-delete image)))
>
> But it outputs "batch command: experienced an execution error."
>
> I learned the basics of Scheme yesterday. Is this some kind of scope  
>  error? Am
> I changing a different "drawable" variable?

Sort of. You have a couple of unwanted parentheses in your 'set!'  
statement and 'drawable' is being treated as a function. The  
appropriate syntax would be:

(set! drawable (car (gimp-image-get-active-layer image)))


You're doing well for only your second day with Scheme. One thing that  
might help you in debugging scripts is using the Script-fu console. If  
you open the console ("Xtns->Script-fu->Script-fu Console") and  
execute your command providing appropriate parameters:

(fuzzy-border-single "/home/milos/somefile.jpg")

then the error messages produced will be somewhat more useful than  
"experienced an execution error".