> > Von: "Amit Kumar Saha" <[EMAIL PROTECTED]>
> > Is there any way to make GIMP plugins themselves extensible. My point
> > here is that, can we make a GIMP plugin which allows itself modifiable
> > by a end-user to include a new functionality without much of a hassle
> > on part of the end-user.
The trick here isn't creating an extensible plugin. The trick is
defining what "without much hassle on the part of the end-user" really
means. Who's the end user? Joe Artist or Edward Engineer? Sven's
granny or a bunch of kernel developers?
In general, making a piece of software extensible requires two main
components: a grammer understandable by the core software and an API
accessible through that grammer to core functionality. One problem
you'll have to address is what parts of the API are visible to the
plugins and what parts are not.
To make a piece of software extendable you could ignore the API portion
and create a simple grammer that end users could use to essentially
configure the plugin. Imagine a simplistic scripting language that
simply sets a bunch of variables that the main plugin normally requires
you to set manually using a series of dialogs or tabs. Wouldn't even
require anything as complex as Perl or Python - it could just be a
series of name/value pairs. But this isn't really extension, its
More complex examples would include exactly what GIMP already does with
it's language extensions. You can load a dll easily enough or embed an
interpreter like Perl or Python. But is programming in Perl or Python
"easy" to your end user? A more common approach these days is to allow
extension via XML. You can easily embed an XML parser into a plugin
(I've used libXML2 in my plugins to save configuration data). But then
you have to decide if writing XML by hand is easy for your users. Not
to mention defining the XML Schema or DTD for the language. In the end,
though, what you've done is create a new programming language. If
you're doing that, and started with the intention of making it easy to
use, you might as well use a well known language like Perl or Python
You could provide a series of core features in the plugin that could be
used in a reorderable stack and then build a GUI that used drag and drop
to rearrange that stack. Sort of like arranging a series of existing
plugins to be run in any given order. The plugin would then process in
the order defined by the stack. The problem here is that you're simply
providing a mechanism for using existing features, not allowing the user
to extend that feature set.
So before you decide on the mechanism, you have to define who will use
it and what you're really trying to allow them to do.
> Does any one know of a method to do this or
> > any GIMP plugin which already does this?
I'm not aware of any plugins that provide this though it wouldn't
suprise me if someone had already done something similar. Plugin
interfaces are a standard part of many applications these days but I
think you'd be hard pressed to find any that don't require some level of
programming expertise to use.
Michael J. Hammel Senior Software Engineer
[EMAIL PROTECTED] http://graphics-muse.org
Memory is a Net - Oliver Wendell Holmes, Sr.
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