I want to write some plug-ins in Prolog.  I don't want to deal with any C pointers, while-loops or if-thens.  Although the code below doesn't make use of it, I want to make use of Prolog backtracking in order to find a correct solution through trial-and-error, such as filling a region with a texture that melds into all edges with no abrupt color differences.  I want to be able to write code such as this, in Prolog, for the blur function for example

blur(In, Out) :- blur(In, Out, In).   %the function needs to access input pixels more than %once (not just when they are at the head of the input list), so pass on another copy of the %input as the 3rd argument blur([], [], _). %when there is no more input, there is no more output, so stop blur( [X-Y-A-R-G-B | Input_Tail], [OX-OY-OA-OR-OG-OB | Output_Tail], Input) :-     %find all the neighbors of current pixel, average them, and unify result with head of     %the output list
    findall( X2-Y2-A2-R2-G2-B2, (
                                                 neighbor(X-Y, X2-Y2),                                                  member(X2-Y2-A2-R2-G2-B2, Input),              Neighbors),
   average_pixels(Neighbors, OX-OY-OA-OR-OG-OB),      blur(Input_Tail, Output_Tail, Input).   %recursion

I want to be able to deal with the input and output in the form of a Prolog list, one list for each layer.  And for multiple layers, a list of lists.  The code above is written for one layer.

Each pixel could come in the form of X-Y-A-R-G-B (integers separated by hyphens) where X and Y are the location coordinates, A is the alpha channel, and R-G-B are their respective RGB values.

I understand that processing the data in Prolog would come with performance drawbacks, but I want to make use of backtracking, and I don't want to be dealing with for-loops and array pointers when I'm defining the output.  If it needs to be optimized somebody could rewrite it into C. 

Is there anyone who has written plug-ins before in the C language that would be able to help me make a Gimp Prolog interface so that Prolog programs can be run from a Gimp plug-in.  I want to have a new plug-in under Filters->Prolog that will open up a list of *.pl files in the plug-ins directory (*.pl meaning Prolog file extension).  I can then choose a *.pl file and the plug-in will then communicate with Prolog.  So in other words, instead of compiling a plug-in for Gimp every time, this single plug-in will be able to run all Prolog programs in their *.pl form as soon as they are written. 

Preferring to work in Prolog I need some help from a C programmer to write this plug-in.  I'd appreciate any help from someone who has written a plug-in before.

Ryan

js, 

Thanks, I believe Python is the solution I was looking for.

- Ryan

--- On Thu, 12/3/09, Joao S. O. Bueno wrote:

From: Joao S. O. Bueno Subject: Re: [Gimp-developer] Gimp prolog interface To: "Ryan Eisele"
Cc: gimp-developer@lists.xcf.berkeley.edu Date: Thursday, December 3, 2009, 1:15 PM

Hi Ryan -

I strongly suggest you learn python instead, and us it for your scripts, instead.

It attends eveeryone of yoru requisites: - no dealing with pointers or memory allocation/deallocation - gimp data structures are provided as high level objects - the language syntax even allows for a funciotnal-like programing if you prefer that.

(for example to interact through layers, you just do: image = gimp.list_images()[0]
for layer in image.layers:
    #your code dealing with the "layer" object

When you get to the pixels you have then as a byte sequence, you then convert to a bytearray (python 2.6)  - to get all the green bytes for the pixels from such an array on a separate array, I could do:

green =[1::4]

Follow the tutorial in www.python.org docs, you could get proficient in the language in less than 1 hour - then check the pythons cripts that come with gimp for examples of the API use and pixel access.

  js   ->